WorldWideScience

Sample records for predatory cladoceran cercopagis

  1. Predatory peace

    DEFF Research Database (Denmark)

    Lund, Christian

    2018-01-01

    The end of the civil war in Aceh brought peace, but it has been of a predatory nature. As a moment of rupture, the peace revealed interests, powers and dynamics, and it offered an opportunity for their reconfiguration. When unrest ceased, old agrarian conflicts between smallholders and planters r....... The study is based on fieldwork in areas where current land conflicts are played out, as well as on secondary sources.......The end of the civil war in Aceh brought peace, but it has been of a predatory nature. As a moment of rupture, the peace revealed interests, powers and dynamics, and it offered an opportunity for their reconfiguration. When unrest ceased, old agrarian conflicts between smallholders and planters...

  2. Predatory peace

    DEFF Research Database (Denmark)

    Lund, Christian

    2017-01-01

    The end of the civil war in Aceh brought peace, but it has been of a predatory nature. As a moment of rupture, the peace revealed interests, powers and dynamics, and it offered an opportunity for their reconfiguration. When unrest ceased, old agrarian conflicts between smallholders and planters r....... The study is based on fieldwork in areas where current land conflicts are played out, as well as on secondary sources.......The end of the civil war in Aceh brought peace, but it has been of a predatory nature. As a moment of rupture, the peace revealed interests, powers and dynamics, and it offered an opportunity for their reconfiguration. When unrest ceased, old agrarian conflicts between smallholders and planters...

  3. Cladoceran birth and death rates estimates

    OpenAIRE

    Gabriel, Wilfried; Taylor, B. E.; Kirsch-Prokosch, Susanne

    1987-01-01

    I. Birth and death rates of natural cladoceran populations cannot be measured directly. Estimates of these population parameters must be calculated using methods that make assumptions about the form of population growth. These methods generally assume that the population has a stable age distribution. 2. To assess the effect of variable age distributions, we tested six egg ratio methods for estimating birth and death rates with data from thirty-seven laboratory populations of Daphnia puli...

  4. Influence of exposure time on the distribution of cadmium within the cladoceran Ceriodaphnia dubia

    International Nuclear Information System (INIS)

    Munger, C.; Hare, L.; Craig, A.; Charest, P.-M.

    1998-01-01

    The internal distribution of a trace metal can be useful in determining in which body organ toxic effects are most likely to occur and the animal function most likely to be affected. In addition, because a metal's distribution within an organism is likely to influence the rate and efficiency with which it is transferred to a higher trophic level, laboratory measurements of trophic transfer could be influenced by exposure duration. We compared the internal distribution of cadmium (Cd) in a cladoceran crustacean (Ceriodaphnia dubia) destined as food for a predatory insect (Chaoborus) after either a 1 day or a lifetime of exposure of prey to the trace metal. Prey were exposed to 112+109 Cd in both water (10 nM) and their food (algae), as might occur in nature. The internal distribution of 109 Cd in the cladoceran was determined by whole-animal autoradiography. Both the amount and the tissue distribution of Cd in prey were the same after the short and the long term exposures, suggesting that metal accumulation parameters measured after short-term metal exposures can be valid for this animal. Cadmium was mainly accumulated in diverticula of the anterior midgut, a region reported to be responsible for nutrient absorption. We hypothesize that Cd is accumulated in the diverticula because of their purported role as sites of calcium uptake. (Copyright (c) 1998 Elsevier Science B.V., Amsterdam. All rights reserved.)

  5. Evolutionary and Ecological Consequences of Interspecific Hybridization in Cladocerans

    NARCIS (Netherlands)

    Schwenk, K.; Spaak, P.

    1995-01-01

    The evolutionary process of interspecific hybridization in cladocerans is reviewed based on ecological and population genetic data. The evolutionary consequences of hybridization, biogeographic patterns and fitness comparisons are analyzed within the conceptual framework of theories on

  6. Cladocerans (Branchiopoda) of a tropical estuary in Brazil

    OpenAIRE

    Paranaguá, M. N; Neumann-Leitão, S; Nogueira-Paranhos, J. D; Silva, T. A.; Matsumura-Tundisi, T.

    2005-01-01

    The study was conducted in the Capibaribe river estuary in Recife (Brazil) to assess the role played by cladocerans in a eutrophic environment. Samplings were carried out monthly at 4 fixed stations along the estuary from July 1987 to June 1988. Collections were made with a plankton net of 65 micrometers mesh size. Six cladocerans species were registered: Penilia avirostris, Diaphanosoma spinulosum, Chydorus barroisi, Ceriodaphnia rigaudi, Ilyocryptus spinifer, and Moina micrura. The most fre...

  7. Antibiotics from predatory bacteria

    Directory of Open Access Journals (Sweden)

    Juliane Korp

    2016-03-01

    Full Text Available Bacteria, which prey on other microorganisms, are commonly found in the environment. While some of these organisms act as solitary hunters, others band together in large consortia before they attack their prey. Anecdotal reports suggest that bacteria practicing such a wolfpack strategy utilize antibiotics as predatory weapons. Consistent with this hypothesis, genome sequencing revealed that these micropredators possess impressive capacities for natural product biosynthesis. Here, we will present the results from recent chemical investigations of this bacterial group, compare the biosynthetic potential with that of non-predatory bacteria and discuss the link between predation and secondary metabolism.

  8. Academic Nightmares: Predatory Publishing

    Science.gov (United States)

    Van Nuland, Sonya E.; Rogers, Kem A.

    2017-01-01

    Academic researchers who seek to publish their work are confronted daily with a barrage of e-mails from aggressive marketing campaigns that solicit them to publish their research with a specialized, often newly launched, journal. Known as predatory journals, they often promise high editorial and publishing standards, yet their exploitive business…

  9. Predatory Open Access in Rehabilitation.

    Science.gov (United States)

    Manca, Andrea; Martinez, Gianluca; Cugusi, Lucia; Dragone, Daniele; Mercuro, Giuseppe; Deriu, Franca

    2017-05-01

    Increasingly scholars and researchers are being solicited by predatory open access journals seeking manuscript submissions and abusing the author-pays model by charging authors with publishing fees without any or proper peer review. Such questionable editorial practices are threatening the reputation and credibility of scholarly publishing. To date, no investigation has been conducted on this phenomenon in the field of rehabilitation. This study attempts to identify specific predatory journals operating in this field to quantify the phenomenon and its geographic distribution. Beall's List has been used to this end which, although not perfect, is a comprehensive and up-to-date report of predatory publishers. Of the 1113 publishers on the list, 59 journals were identified, for a total of 5610 published articles. The median number of articles published by each journal was 21, and the median amount of article processing charges was $499. Only 1 out of 59 journals was included in the Directory of Open Access Journals, whereas 7 (12%) were indexed by PubMed. Most of the publishers were based in India (36%) followed by the United States (25%) and Pakistan (5%), and 25% were without a verifiable address. The data indicate that the threat of predatory publishing in rehabilitation is real. Physiatrists, physiotherapists, researchers, and academics operating in this field are advised to use the tools available to recognize predatory practices before considering publishing in open access journals. Copyright © 2017 American Congress of Rehabilitation Medicine. Published by Elsevier Inc. All rights reserved.

  10. Predatory senescence in ageing wolves.

    Science.gov (United States)

    MacNulty, Daniel R; Smith, Douglas W; Vucetich, John A; Mech, L David; Stahler, Daniel R; Packer, Craig

    2009-12-01

    It is well established that ageing handicaps the ability of prey to escape predators, yet surprisingly little is known about how ageing affects the ability of predators to catch prey. Research into long-lived predators has assumed that adults have uniform impacts on prey regardless of age. Here we use longitudinal data from repeated observations of individually-known wolves (Canis lupus) hunting elk (Cervus elaphus) in Yellowstone National Park to demonstrate that adult predatory performance declines with age and that an increasing ratio of senescent individuals in the wolf population depresses the rate of prey offtake. Because this ratio fluctuates independently of population size, predatory senescence may cause wolf populations of equal size but different age structure to have different impacts on prey populations. These findings suggest that predatory senescence is an important, though overlooked, factor affecting predator-prey dynamics.

  11. Predatory senescence in aging wolves

    Science.gov (United States)

    MacNulty, Daniel R.; Smith, Douglas W.; Vucetich, John A.; Mech, L. David; Stahler, Daniel R.; Packer, Craig

    2009-01-01

    It is well established that ageing handicaps the ability of prey to escape predators, yet surprisingly little is known about how ageing affects the ability of predators to catch prey. Research into long-lived predators has assumed that adults have uniform impacts on prey regardless of age. Here we use longitudinal data from repeated observations of individually-known wolves (Canis lupus) hunting elk (Cervus elaphus) in Yellowstone National Park to demonstrate that adult predatory performance declines with age and that an increasing ratio of senescent individuals in the wolf population depresses the rate of prey offtake. Because this ratio fluctuates independently of population size, predatory senescence may cause wolf populations of equal size but different age structure to have different impacts on prey populations. These findings suggest that predatory senescence is an important, though overlooked, factor affecting predator-prey dynamics.

  12. Predatory senescence in ageing wolves

    Science.gov (United States)

    MacNulty, D.R.; Smith, D.W.; Vucetich, J.A.; Mech, L.D.; Stahler, D.R.; Packer, C.

    2009-01-01

    It is well established that ageing handicaps the ability of prey to escape predators, yet surprisingly little is known about how ageing affects the ability of predators to catch prey. Research into long-lived predators has assumed that adults have uniform impacts on prey regardless of age. Here we use longitudinal data from repeated observations of individually-known wolves (Canis lupus) hunting elk (Cervus elaphus) in Yellowstone National Park to demonstrate that adult predatory performance declines with age and that an increasing ratio of senescent individuals in the wolf population depresses the rate of prey offtake. Because this ratio fluctuates independently of population size, predatory senescence may cause wolf populations of equal size but different age structure to have different impacts on prey populations. These findings suggest that predatory senescence is an important, though overlooked, factor affecting predator-prey dynamics. ?? 2009 Blackwell Publishing Ltd/CNRS.

  13. Cost of reproduction in selected species of zooplankton (rotifers and cladocerans)

    NARCIS (Netherlands)

    Sarma, S.S.S.; Nandini, S.; Gulati, R.D.

    2002-01-01

    Reproduction is an energetically costly biological process. Among the freshwater zooplankton, rotifers and cladocerans reproduce parthenogenetically and the cost of reproduction can be estimated using the life table data from demographic studies. Reduced probability of future survival or future

  14. Winter swarming behavior by the exotic cladoceran Daphnia lumholtzi Sars, 1885 in a Kentucky (USA) reservoir

    Science.gov (United States)

    Beaver, John R.; Renicker, Thomas R.; Tausz, Claudia E.; Young, Jade L.; Thomason, Jennifer C.; Wolf, Zachary L.; Russell, Amber L.; Cherry, Mac A.; Scotese, Kyle C.; Koenig, Dawn T.

    2018-01-01

    We describe swarming behavior in the invasive cladoceran Daphnia lumholtzi Sars, 1885 in a Kentucky, USA, reservoir during winter 2017. The taxon is a highly successful tropical invader and has spread throughout the lower latitude systems in the USA since its discovery in 1991. Other than a few isolated reports, the abundance of D. lumholtzi is often 10,000 organisms L-1) of sexually reproducing females of this exotic cladoceran at water column temperatures <10°C.

  15. Detecting Predatory Behaviour in Online Game Chats

    DEFF Research Database (Denmark)

    Gudnadottir, Elin Rut; Jensen, Alaina K.; Cheong, Yun-Gyung

    This paper describes a machine learning approach to detect sexually predatory behaviour in the massively multiplayer online game for children, MovieStarPlanet. The goal of this work is to take a chat log as an input and outputs its label as either the predatory category or the non......-predatory category. From the raw in-game chat logs provided by MovieStarPlanet, we first prepared three sub datasets via extensive preprocessing. Then, two machine learning algorithms, naive Bayes and Decision Tree, were employed to model the predatory behaviour using different feature sets. Our evaluation has...

  16. How does the Taquari River influence in the cladoceran assemblages in three oxbow lakes?

    Directory of Open Access Journals (Sweden)

    EA. Panarelli

    Full Text Available This study examined the cladoceran assemblages in three oxbow lakes of the Taquari River floodplain, near the transition between the plateau and the plain. We sought to answer the following questions: does the Taquari River function as a geographical barrier or dispersal corridor for Cladocera? Can different degrees of connection induce different structures in the assemblages in each lake? Cladocerans and limnological variables were sampled every other month for one year. Forty-one species were recorded, four of which were common to all the lakes. Our results indicated that the different degrees of connection between the river and the oxbow lakes favoured environmental heterogeneity and diversification in the cladoceran assemblages. The greatest dissimilarity between the two lakes connected with the river indicates that in this case the river functions better as a barrier than a dispersal corridor.

  17. Development of tolerance against toxic Microcystis aeruginosa in three cladocerans and the ecological implications

    International Nuclear Information System (INIS)

    Guo Nichun; Xie Ping

    2006-01-01

    This is the first experimental study to compare difference in the development of tolerance against toxic Microcystis among multi-species of cladocerans (Daphnia, Moina and Ceriodaphnia) pre-exposed to two M. aeruginosa PCC7820 strains (MC-containing and MC-free). Zooplankton were divided into S population (fed Scenedesmus), M-F population (fed Scenedesmus + MC-free Microcystis), and M-C population (fed Scenedesmus + MC-containing Microcystis). M-F and M-C populations were pre-exposed to Microcystis strains for 4 weeks, and their newborns were collected for experiments. A pre-exposure to MC-containing or MC-free Microcystis increased tolerance against toxic Microcystis. The marked increases in survival rate and median lethal time (LT 5 , 100-194% increase) in the M-C population of Ceriodaphnia suggest that small-sized cladocerans may develop stronger tolerance against Microcystis than large-sized ones when both groups are exposed to toxic Microcystis. This may explain why dominant Daphnia is usually replaced by small-sized cladocerans when cyanobacteria bloomed in summer in eutrophic lakes. - Three cladocerans pre-exposed to Microcystis developed different tolerance against toxic Microcystis, explaining zooplankton succession with blooms

  18. Development of tolerance against toxic Microcystis aeruginosa in three cladocerans and the ecological implications

    Energy Technology Data Exchange (ETDEWEB)

    Guo Nichun [Donghu Experimental Station of Lake Ecosystems, State Key Laboratory of Freshwater Ecology and Biotechnology of China, Institute of Hydrobiology, Chinese Academy of Sciences, Donghu South Road 7, Wuhan 430072 (China); Xie Ping [Donghu Experimental Station of Lake Ecosystems, State Key Laboratory of Freshwater Ecology and Biotechnology of China, Institute of Hydrobiology, Chinese Academy of Sciences, Donghu South Road 7, Wuhan 430072 (China)]. E-mail: xieping@ihb.ac.cn

    2006-10-15

    This is the first experimental study to compare difference in the development of tolerance against toxic Microcystis among multi-species of cladocerans (Daphnia, Moina and Ceriodaphnia) pre-exposed to two M. aeruginosa PCC7820 strains (MC-containing and MC-free). Zooplankton were divided into S population (fed Scenedesmus), M-F population (fed Scenedesmus + MC-free Microcystis), and M-C population (fed Scenedesmus + MC-containing Microcystis). M-F and M-C populations were pre-exposed to Microcystis strains for 4 weeks, and their newborns were collected for experiments. A pre-exposure to MC-containing or MC-free Microcystis increased tolerance against toxic Microcystis. The marked increases in survival rate and median lethal time (LT{sub 5}, 100-194% increase) in the M-C population of Ceriodaphnia suggest that small-sized cladocerans may develop stronger tolerance against Microcystis than large-sized ones when both groups are exposed to toxic Microcystis. This may explain why dominant Daphnia is usually replaced by small-sized cladocerans when cyanobacteria bloomed in summer in eutrophic lakes. - Three cladocerans pre-exposed to Microcystis developed different tolerance against toxic Microcystis, explaining zooplankton succession with blooms.

  19. Long-term trends in abundance of cladocerans in the Central Baltic Sea

    DEFF Research Database (Denmark)

    Möllmann, C.; Köster, Fritz; Kornilovs, G.

    2002-01-01

    on the abundance of cladoceran species was investigated. A clear affinity to higher temperature was found for B. coregoni maritima in summer as well as for E. nordmanni and Podon spp. in spring. In addition to temperature, association tests with salinity revealed besides species-specific preferences, regional...

  20. Seasonal dynamics and life histories of pelagic cladocerans (Crustacea; Cladocera in an acid boreal lake

    Directory of Open Access Journals (Sweden)

    Jens Petter NILSSEN

    2011-02-01

    Full Text Available In the surveyed anthropogenic acidified Lake Gjerstadvann with pH ≈ 5.2 situated in southern Norway, spatial and temporal distribution of three characteristic planktonic cladocerans inhabiting acidified boreal biotopes, Bosmina longispina, Holopedium gibberum, and Diaphanosoma brachyurum, were studied over a period of one year. The major pelagic predator was Eurasian perch, Perca fluviatilis. The local perch probably balanced the cladoceran community and facilitated co-existence of all three species of cladocerans by removing significant portions of B. longispina, which could also be the case in similar types of boreal lakes. Invertebrate predators such as the dipteran larvae Chaoborus flavicans and carnivorous copepods did not seem to influence the cladoceran community. B. longispina was perennial, whereas both H. gibberum and D. brachyurum were recorded only during the ice-free period. The life cycle of these free-living pelagic species ranged from 2-3 in D. brachyurum, 3 in H. gibberum to approximately 6 annual generations in B. longispina. Wintering took place as resting eggs in D. brachyurum and H. gibberum, while B. longispina produced resting eggs in addition to an active planktonic stay. The warm water tolerant D. brachyurum was mainly distributed above the thermocline, whereas H. gibberum also inhabited deeper strata, and B. longispina most vertical strata of the lake. Maximum seasonal clutch volume of B. longispina coincided in time with peak in food abundance and may be a useful parameter to identify planktonic food availability in such lakes. Knowledge of the autecology and life history of species is fundamental for understanding ecosystem stress, such as anthropogenic acidification and recovery through liming or by natural causes. Seasonal depth isoplots combined with life history studies of commonly co-occurring cladoceran species from natural acid and anthropogenic acidified lakes on the Northern Hemisphere seem to be uncommon

  1. Cladoceran-inferred environmental change during the LGM to Holocene transition from Onepoto maar paleolake, Auckland, New Zealand

    International Nuclear Information System (INIS)

    Kattel, G.R.; Augustinus, P.C.

    2010-01-01

    Subfossil cladocerans have rarely been used for paleoenvironmental reconstruction from New Zealand lake sediments, and here we detail the first examination of the response of cladocerans to past environments from an Auckland maar paleolake. Cladoceran remains were examined in the upper 230 cm of the lacustrine sediments spanning c. 9-31 cal. ka BP from Onepoto maar during which time the lake underwent significant changes. Lake level was relatively high during the Last Glacial Coldest Period (c. 28-18 cal. ka BP), with limited forest in the catchment, shoreline vegetation and low water temperature indicated by the presence of a planktonic taxon, Bosmina meridionalis, and a cold tolerant chydorid cladoceran Alona sp. (affinis type). However, the climate during the last glacial termination after c. 17.9 cal. ka BP changed abruptly, perhaps becoming extremely dry and windy, resulting in increased production of cladoceran resting eggs. Between c. 17.6 and 14.1 cal. ka BP, a gradually ameliorating climate with sustained windiness and dryness might have been unfavourable for hatching of chydorid cladoceran eggs and their recolonisation. After c. 14.1 cal. ka BP, continued climatic amelioration was accompanied by reduced lake levels inferred from high cladoceran littoral: planktonic ratios as well as increased cladoceran diversity and abundance of less cold tolerant chydorid taxa: Alona guttata, Alona sp. (intermedia type) and Alonella excisa. At c. 9 cal. ka BP, the maar crater rim was breached by the marine waters commensurate with postglacial sea-level rise, resulting in degraded water quality and production of a large number of cladoceran ephippia in the sediments. (author). 67 refs., 3 figs., 2 tabs.

  2. Lake depth rather than fish planktivory determines cladoceran community structure in Faroese lakes - evidence from contemporary data and sediments

    DEFF Research Database (Denmark)

    Amsinck, S.L.; Strzelczak, A.; Bjerring, R.

    2006-01-01

    development was inferred by cladoceran-based paleolimnological investigations of a 14C-dated sediment core covering the last ca 5700 years. 3. The 29 study lakes were overall shallow, small-sized, oligotrophic and dominated by brown trout (Salmo trutta). Cladoceran species richness was overall higher...... depth. A recent increase in inferred Zmax may, however, be an artefact induced by, for instance, eutrophication....

  3. Differences in susceptibility of five cladoceran species to two systemic insecticides, imidacloprid and fipronil.

    Science.gov (United States)

    Hayasaka, Daisuke; Korenaga, Tomoko; Suzuki, Kazutaka; Sánchez-Bayo, Francisco; Goka, Koichi

    2012-03-01

    Differences in susceptibility of five cladocerans to the neonicotinoid imidacloprid and the phenyl-pyrazole fipronil, which have been dominantly used in rice fields of Japan in recent years, were examined based on short-term (48-h), semi-static acute immobilization exposure tests. Additionally, we compared the species sensitivity distribution (SSD) patterns of both insecticides between two sets of species: the five tested cladocerans and all other aquatic organisms tested so far, using data from the ECOTOX database of U.S. Environmental Protection Agency (USEPA). The sensitivity of the test species to either imidacloprid or fipronil was consistent, spanning similar orders of magnitude (100 times). At the genus level, sensitivities to both insecticides were in the following descending order: Ceriodaphnia > Moina > Daphnia. A positive relationship was found between body lengths of each species and the acute toxicity (EC(50)) of the insecticides, in particular fipronil. Differences in SSD patterns of imidacloprid were found between the species groups compared, indicating that test cladocerans are much less susceptible than other aquatic species including amphibians, crustaceans, fish, insects, mollusks and worms. However, the SSD patterns for fipronil indicate no difference in sensitivity between cladocerans tested and other aquatic organisms despite the greater exposure, which overestimates the results, of our semi-static tests. From these results, Ceriodaphnia sp. should be considered as more sensitive bioindicators (instead of the standard Daphnia magna) for ecotoxicological assessments of aquatic ecosystems. In addition, we propose that ecotoxicity data associated with differences in susceptibility among species should be investigated whenever pesticides have different physicochemical properties and mode of action.

  4. Copper toxicity to different field-collected cladoceran species: intra-and inter-species sensitivity

    International Nuclear Information System (INIS)

    Bossuyt, Bart T.A.; Janssen, Colin R.

    2005-01-01

    The acute copper sensitivity of 44 European freshwater cladocerans, from four families (Daphniidae, Bosminidae, Macrothricidae, Chydoridae) and 13 genera (Daphnia, Ctenodaphnia, Ceriodaphnia, Simocephalus, Scapholeberis, Bosmina, Acantholeberis, Alona, Acroperus, Chydorus, Eurycercus, Disparalona and Pleuroxus) were assayed. The 48-h EC 50 s of field-collected organisms tested in reconstituted standard laboratory water ranged from 5.3 to 70.6 μg Cu L -1 . Only among Ctenodaphnia were significant intra-species differences observed. Significant inter-species differences were noted among Alonina and Daphnia. Between all genera tested, a maximum of a 12-fold difference in copper sensitivity was noted. Most animals were more sensitive than a laboratory D. magna clone. A weak non-significant increasing trend was noted between mean cladoceran 48-h EC 50 and ambient copper concentration of the different aquatic systems, suggesting acclimation/adaptation in the field. A positive relationship was also observed between the 48-h EC 50 of the field-collected cladoceran species (without the Chydoridae family) and the size of the organisms. - Zooplankton living in natural waters are more sensitive to copper than laboratory animals

  5. Copper toxicity to different field-collected cladoceran species: intra-and inter-species sensitivity

    Energy Technology Data Exchange (ETDEWEB)

    Bossuyt, Bart T.A. [Laboratory of Environmental Toxicology and Aquatic Ecology, Ghent University, J. Plateaustraat 22, B-9000 Ghent (Belgium)]. E-mail: bart.bossuyt@ugent.be; Janssen, Colin R. [Laboratory of Environmental Toxicology and Aquatic Ecology, Ghent University, J. Plateaustraat 22, B-9000 Ghent (Belgium)

    2005-07-15

    The acute copper sensitivity of 44 European freshwater cladocerans, from four families (Daphniidae, Bosminidae, Macrothricidae, Chydoridae) and 13 genera (Daphnia, Ctenodaphnia, Ceriodaphnia, Simocephalus, Scapholeberis, Bosmina, Acantholeberis, Alona, Acroperus, Chydorus, Eurycercus, Disparalona and Pleuroxus) were assayed. The 48-h EC{sub 50}s of field-collected organisms tested in reconstituted standard laboratory water ranged from 5.3 to 70.6 {mu}g Cu L{sup -1}. Only among Ctenodaphnia were significant intra-species differences observed. Significant inter-species differences were noted among Alonina and Daphnia. Between all genera tested, a maximum of a 12-fold difference in copper sensitivity was noted. Most animals were more sensitive than a laboratory D. magna clone. A weak non-significant increasing trend was noted between mean cladoceran 48-h EC{sub 50} and ambient copper concentration of the different aquatic systems, suggesting acclimation/adaptation in the field. A positive relationship was also observed between the 48-h EC{sub 50} of the field-collected cladoceran species (without the Chydoridae family) and the size of the organisms. - Zooplankton living in natural waters are more sensitive to copper than laboratory animals.

  6. Sedimentary Record of Cladoceran Functionality under Eutrophication and Re-Oligotrophication in Lake Maggiore, Northern Italy

    Directory of Open Access Journals (Sweden)

    Liisa Nevalainen

    2018-01-01

    Full Text Available We examined fossil Cladocera (Crustacea communities and their functional assemblages in a ~60-year sediment record from Lake Maggiore, northern Italy. Our main objective was to document the response of aquatic community functioning to environmental stress during eutrophication (1960–1985 and recovery (post-1985, and to identify environmental controls on cladoceran functionality. Of the functional groups, large filter feeders and oval epibenthos thrived prior to eutrophication (reference conditions pre-1960 and globular epibenthos and small filter feeders increased during eutrophication and as the lake recovered. Multivariate analyses suggested that bottom-up controls (i.e., total phosphorus were important for shaping functional assemblages but taxonomic community changes were likely related to top-down control by predators, particularly the predaceous cladoceran Bythotrephes longimanus. Functional diversity (FD was higher and Daphnia ephippia length (DEL larger during the reference and early eutrophication periods and decreased during eutrophication and recovery. Both FD (high and DEL (large were distinct during reference period, but were similar (FD low, DEL small between the eutrophication and recovery periods. The functional attributes and the assemblages did not recover post-eutrophication, suggesting that the system exhibited a clear shift to low FD and dominance of small filterers. Cladoceran functionality appears to be related to fundamental ecosystem functions, such as productivity, and may thus provide insights for long-term changes in ecological resilience.

  7. Development and application of a sediment toxicity test using the benthic cladoceran Chydorus sphaericus

    International Nuclear Information System (INIS)

    Dekker, T.; Greve, G.D.; Ter Laak, T.L.; Boivin, M.E.; Veuger, B.; Gortzak, G.; Dumfries, S.; Luecker, S.M.G.; Kraak, M.H.S.; Admiraal, W.; Geest, H.G. van der

    2006-01-01

    This study reports on the development and application of a whole sediment toxicity test using a benthic cladoceran Chydorus sphaericus, as an alternative for the use of pelagic daphnids. A C. sphaericus laboratory culture was started and its performance under control conditions was optimised. The test was firstly validated by determining dose-response relationships for aqueous cadmium and copper and ammonia, showing a sensitivity of C. sphaericus (96 h LC 5 values of 594 μg Cd/L, 191 μg Cu/L and 46 mg ammonia/L at pH 8) similar to that of daphnids. Next, sediment was introduced into the test system and a series of contaminated sediments from polluted locations were tested. A significant negative correlation between survival and toxicant concentrations was observed. It is concluded that the test developed in the present study using the benthic cladoceran C. sphaericus is suitable for routine laboratory sediment toxicity testing. - A test was developed for assaying sediment toxicity using a commonly occurring small-bodied cladoceran

  8. Ethical issues in publishing in predatory journals.

    Science.gov (United States)

    Ferris, Lorraine E; Winker, Margaret A

    2017-06-15

    Predatory journals, or journals that charge an article processing charge (APC) to authors, yet do not have the hallmarks of legitimate scholarly journals such as peer review and editing, Editorial Boards, editorial offices, and other editorial standards, pose a number of new ethical issues in journal publishing. This paper discusses ethical issues around predatory journals and publishing in them. These issues include misrepresentation; lack of editorial and publishing standards and practices; academic deception; research and funding wasted; lack of archived content; and undermining confidence in research literature. It is important that the scholarly community, including authors, institutions, editors, and publishers, support the legitimate scholarly research enterprise, and avoid supporting predatory journals by not publishing in them, serving as their editors or on the Editorial Boards, or permitting faculty to knowingly publish in them without consequences.

  9. Study of Predatory Open Access Nursing Journals.

    Science.gov (United States)

    Oermann, Marilyn H; Conklin, Jamie L; Nicoll, Leslie H; Chinn, Peggy L; Ashton, Kathleen S; Edie, Alison H; Amarasekara, Sathya; Budinger, Susan C

    2016-11-01

    The purpose of this study was to identify predatory journals in nursing, describe their characteristics and editorial standards, and document experiences of authors, peer reviewers, and editors affiliated with these journals. Using two sources that list predatory journals, the research team created a list of nursing journals. In Phase One, the team collected data on characteristics of predatory nursing journals such as types of articles published, article processing charge, and peer review process. In Phase Two, the team surveyed a sample of authors, reviewers, and editors to learn more about their experiences with their affiliated journals. Data from the review of predatory nursing journals were analyzed using descriptive statistics. Written comments were summarized and categorized. There were 140 predatory nursing journals from 75 publishers. Most journals were new, having been inaugurated in the past 1 to 2 years. One important finding was that many journals only published one or two volumes and then either ceased publishing or published fewer issues and articles after the first volume. Journal content varied widely, and some journals published content from dentistry and medicine, as well as nursing. Qualitative findings from the surveys confirmed previously published anecdotal evidence, including authors selecting journals based on spam emails and inability to halt publication of a manuscript, despite authors' requests to do so. Predatory journals exist in nursing and bring with them many of the "red flags" that have been noted in the literature, including lack of transparency about editorial processes and misleading information promoted on websites. The number of journals is high enough to warrant concern in the discipline about erosion of our scholarly literature. Nurses rely on the published literature to provide evidence for high-quality, safe care that promotes optimal patient outcomes. Research published in journals that do not adhere to the highest

  10. Environmental and spatial factors influencing the distribution of cladocerans in lakes across the central Canadian Arctic treeline region

    Directory of Open Access Journals (Sweden)

    John P. SMOL

    2010-02-01

    Full Text Available We examine the role of local environmental and spatial factors in explaining variation in the composition of cladoceran assemblages from surface sediments within a set of 50 lakes spanning a broad southwest to northeast transect across the central Canadian Arctic treeline region from Yellowknife (Northwest Territories to the northern boundary of the Thelon Game Sanctuary (Nunavut Territory. Within each lake, the cladoceran fauna was identified based on the subfossil exoskeletal remains preserved in recently deposited lake sediments. Physical and chemical limnological data were measured in August of 1996 and 1998. Spatial data were generated based on latitude and longitude using Principal Coordinates of Neighbors Matrices analysis (PCNM. The relationships between cladocerans and the measured environmental and spatial variables were examined using both unconstrained (Principal Components Analysis, PCA and constrained (Redundancy Analysis, RDA ordination techniques. Variance partitioning, based on partial RDAs, was used to identify the relative importance of significant environmental and spatial explanatory variables. Three environmental variables were identified as significantly influencing cladoceran community structure: surface water temperature, dissolved organic carbon (DOC, and total phosphorus (TP. Five PCNM-generated spatial variables were also significant in explaining cladoceran distributions. Variance partitioning attributed 14% of the variance in the distribution of Cladocera to spatial factors, an additional 10% to spatially-structured environmental variables, and 8% to environmental factors that were not spatially-structured. Within the central Canadian Arctic treeline region, spatial and other environmental processes had an important influence on the distribution of cladoceran communities. The strong influence of spatial factors was related to the large ecoclimatic gradient across treeline. The distribution patterns of cladocerans

  11. Predatory Journals, Peer Review, and Education Research

    Science.gov (United States)

    Beall, Jeffrey

    2017-01-01

    This commentary examines the problem of predatory journals, low-quality open-access journals that seek to earn revenue from scholarly authors without following scholarly publishing best practices. Seeking to accept as many papers as possible, they typically do not perform a standard peer review, leading to the publication of improperly vetted…

  12. Predatory publishing and cybercrime targeting academics.

    Science.gov (United States)

    Umlauf, Mary Grace; Mochizuki, Yuki

    2018-04-01

    The purpose of this report is to inform and warn academics about practices used by cybercriminals who seek to profit from unwary scholars and undermine the industry of science. This report describes the signs, symptoms, characteristics, and consequences of predatory publishing and related forms of consumer fraud. Methods to curb these cybercrimes include educating scholars and students about tactics used by predatory publishers; institutional changes in how faculty are evaluated using publications; soliciting cooperation from the industries that support academic publishing and indexing to curb incorporation of illegitimate journals; and taking an offensive position by reporting these consumer fraud crimes to the authorities. Over and above the problem of publishing good science in fraudulent journals, disseminating and citing poor-quality research threaten the credibility of science and of nursing. © 2018 John Wiley & Sons Australia, Ltd.

  13. Lateralization of eye use in cuttlefish: opposite direction for anti-predatory and predatory behaviors.

    Directory of Open Access Journals (Sweden)

    Alexandra Kerstin Schnell

    2016-12-01

    Full Text Available Vertebrates with laterally placed eyes typically exhibit preferential eye use for ecological activities such as scanning for predators or prey. Processing visual information predominately through the left or right visual field has been associated with specialized function of the left and right brain. Lateralized vertebrates often share a general pattern of lateralized brain function at the population level, whereby the left hemisphere controls routine behaviors and the right hemisphere controls emergency responses. Recent studies have shown evidence of preferential eye use in some invertebrates, but whether the visual fields are predominately associated with specific ecological activities remains untested. We used the European common cuttlefish, Sepia officinalis, to investigate whether the visual field they use is the same, or different, during anti-predatory and predatory behavior. To test for lateralization of anti-predatory behavior, individual cuttlefish were placed in a new environment with opaque walls, thereby obliging them to choose which eye to orient away from the opaque wall to scan for potential predators (i.e. vigilant scanning. To test for lateralization of predatory behavior, individual cuttlefish were placed in the apex of an isosceles triangular arena and presented with two shrimp in opposite vertexes, thus requiring the cuttlefish to choose between attacking a prey item to the left or to the right of them. Cuttlefish were significantly more likely to favor the left visual field to scan for potential predators and the right visual field for prey attack. Moreover, individual cuttlefish that were leftward directed for vigilant scanning were predominately rightward directed for prey attack. Lateralized individuals also showed faster decision-making when presented with prey simultaneously. Cuttlefish appear to have opposite directions of lateralization for anti-predatory and predatory behavior, suggesting that there is functional

  14. Lateralization of Eye Use in Cuttlefish: Opposite Direction for Anti-Predatory and Predatory Behaviors.

    Science.gov (United States)

    Schnell, Alexandra K; Hanlon, Roger T; Benkada, Aïcha; Jozet-Alves, Christelle

    2016-01-01

    Vertebrates with laterally placed eyes typically exhibit preferential eye use for ecological activities such as scanning for predators or prey. Processing visual information predominately through the left or right visual field has been associated with specialized function of the left and right brain. Lateralized vertebrates often share a general pattern of lateralized brain function at the population level, whereby the left hemisphere controls routine behaviors and the right hemisphere controls emergency responses. Recent studies have shown evidence of preferential eye use in some invertebrates, but whether the visual fields are predominately associated with specific ecological activities remains untested. We used the European common cuttlefish, Sepia officinalis , to investigate whether the visual field they use is the same, or different, during anti-predatory, and predatory behavior. To test for lateralization of anti-predatory behavior, individual cuttlefish were placed in a new environment with opaque walls, thereby obliging them to choose which eye to orient away from the opaque wall to scan for potential predators (i.e., vigilant scanning). To test for lateralization of predatory behavior, individual cuttlefish were placed in the apex of an isosceles triangular arena and presented with two shrimp in opposite vertexes, thus requiring the cuttlefish to choose between attacking a prey item to the left or to the right of them. Cuttlefish were significantly more likely to favor the left visual field to scan for potential predators and the right visual field for prey attack. Moreover, individual cuttlefish that were leftward directed for vigilant scanning were predominately rightward directed for prey attack. Lateralized individuals also showed faster decision-making when presented with prey simultaneously. Cuttlefish appear to have opposite directions of lateralization for anti-predatory and predatory behavior, suggesting that there is functional specialization of

  15. First records of a European cladoceran, Bythotrephes cederstroemi, in Lakes Erie and Huron

    Science.gov (United States)

    Bur, Michael T.; Klarer, David M.; Krieger, Kenneth A.

    1986-01-01

    Adult forms of the cladoceran Bythotrephes cederstroemi Schoedler (Cercopagidae), a widespread European freshwater zooplankter, occurred in the stomachs of four common species of Lake Erie fish (yellow perch, Perca flavescens; white perch, Morone americana; white bass, M. chrysops; and walleye, Stizostedion vitreum vitreum) collected in early October 1985. The fish were collected at several stations in the nearshore open waters of the central basin between Ashtabula and Huron, Ohio. Other investigators have seen this species in other locations in Lake Erie and also in Lake Huron. The report of B. cederstroemi in Lake Huron in December 1984 appears to be the first record of this species in North America.

  16. Biomonitoring of cyanotoxins in two tropical reservoirs by cladoceran toxicity bioassays.

    Science.gov (United States)

    da S Ferrão-Filho, Aloysio; Soares, Maria Carolina S; de Freitas Magalhães, Valeria; Azevedo, Sandra M F O

    2009-02-01

    This study evaluates the potential for the use of cladocerans in biomonitoring of cyanobacterial toxins. Two zooplankton species (Daphnia gessneri and Moina micrura) were cultivated in the laboratory for use in acute (48 h) and chronic (10 days) bioassays. Water samples were collected from two reservoirs and diluted in mineral water at four concentrations. Survivorship in the acute bioassays was used to calculate LC50, and survivorship and fecundity in chronic bioassays were used to calculate the intrinsic population growth rate (r) and the EC50. Analysis of phytoplankton in the water samples from one reservoir revealed that cyanobacteria were the dominant group, represented by the genera Anabaena, Cylindrospermopsis, and Microcystis. Results of bioassays showed adverse effects including death, paralysis, and reduced population growth rate, generally proportional to the reservoir water concentration. These effects may be related to the presence of cyanobacteria toxins (microcystins or saxitoxins) in the water.

  17. Carbon transfer from dissolved organic carbon to the cladoceran Bosmina: a mesocosm study

    Directory of Open Access Journals (Sweden)

    Tang Yali

    2017-01-01

    Full Text Available A mesocosm study illuminated possible transfer pathways for dissolved organic carbon from the water column to zooplankton. Organic carbon was added as 13C enriched glucose to 15 mesocosms filled with natural lake water. Stable isotope analysis and phospholipid fatty acids-based stable isotope probing were used to trace the incorporation of 13C into the cladoceran Bosmina and its potential food items. Glucose-C was shown to be assimilated into phytoplankton (including fungi and heterotrophic protists, bacteria and Bosmina, all of which became enriched with 13C during the experiment. The study suggests that bacteria play an important role in the transfer of glucose-C to Bosmina. Furthermore, osmotic algae, fungi and heterotrophic protists might also contribute to the isotopic signature changes observed in Bosmina. These findings help to clarify the contribution of dissolved organic carbon to zooplankton and its potential pathways.

  18. Predatory Journals and Perished Articles; a Letter to Editor

    OpenAIRE

    Narimani, Mashallah; Dadkhah, Mehdi

    2017-01-01

    In recent years, academic publishing has been faced with many destructive phenomena. “Predatory publishers” (or journals) are one challenge for  cholarly publishing. This term was introduced to academic societies for the first time by Jeffrey Beall in 2010. This letter to editor is about predatory journals and perished articles in the field of emergency medicine.

  19. Arbitral action and preventive methods against predatory journal practice

    Directory of Open Access Journals (Sweden)

    Sung Pil Park

    2018-02-01

    Full Text Available As open access model of journal publication increases, predatory journals, which deceive scholars to publish journals in fake database websites and exploit them for publishing fee, is also increasing. There are two types of predatory journals. First, journal hijacking and cybersquatting generally create fake database website by mimicking authentic database website, thereby defrauding scholars for publication fee. Second, journal phishing use scam emails to steal scholars’ personal information. If scholars suffered damage from predatory journals, scholars can take either arbitral or judicial actions. Arbitral action follows arbitrational resolution process termed Uniform Domain-Name Dispute-Resolution Policy. Scholars can join Uniform Domain-Name Dispute-Resolution Policy proceeding with legal entity that has right to authentic database website, which will result in cancellation or transfer of fake database website. In contrast, scholars can take judicial action under Anticybersquatting Consumer Protection Act, which may help scholars to recover an actual monetary damage from predatory journals. Nonetheless, taking precaution to avoid predatory journals is the best course of action, rather than going through arduous cure procedures. Scholars may prevent predatory journals by carefully examining fake database website names or email addresses, or observing unreasonable number of published article issues in predatory journal websites.

  20. Diversity and abundance of littoral cladocerans and copepods in nine Ecuadorian highland lakes

    Directory of Open Access Journals (Sweden)

    Leticia E Torres

    2006-03-01

    Full Text Available The diversity and abundance of littoral cladocerans and copepods were studied in nine lakes at Reserva Ecológica Cayambe-Coca (Páramo de Guamaní, Ecuador. Six samples were taken in the littoral zone of each lake using a 500 µm mesh plankton conic net. One species of cladocerans (Ephemeroporus acanthoides is reported for the first time in Ecuador. The diversity (H’ and evenness (E of the lakes were determined and correlated with PCA axes based on their environmental variables. The principal parameters that distinguished these lakes were altitude and pH, an unexpected finding considering that the altitudinal range was very small. Lake size is of secondary importance for this group of lakes. None of the environmental axes correlated with H’ or E; nevertheless, a larger than expected species richness was found in a small oligotrophic lake with a high level of DO. Based on our results, we hypothesize that altitude and pH are important factors determining the zooplankton diversity (directly or indirectly in highland lakes. Rev. Biol. Trop. 54 (1: 131-137. Epub 2006 Mar 31.La diversidad y abundancia de cladóceros y copépodos de la zona litoral de nueve lagos fue estudiada en la Reserva Ecológica Cayambe-Coca (Páramo de Guamaní, Ecuador. Seis muestras fueron tomadas en la zona litoral de cada lago utilizando una red conica para plancton de 500 µm de apertura. Una especie de cladócero (Ephemeroporus acanthoides es informada por primera vez en Ecuador. La diversidad (H’ y equitatividad (E fueron determinadas y correlacionadas con los ejes del PCA basado en variables ambientales de los lagos. Los principales parámetros que distinguen estos lagos fueron la altitud y el pH, hallazgo inesperado dado el estrecho ámbito altitudinal. El tamaño parece ser secundario en importancia para este grupo de lagos. No se encontró una correlación significativa entre ninguno de los ejes ambientales y los indices H’ o E; sin embargo, la riqueza de

  1. Behind the Spam: A ``Spectral Analysis'' of Predatory Publishers

    Science.gov (United States)

    Beall, Jeffrey

    2016-10-01

    Most researchers today are bombarded with spam email solicitations from questionable scholarly publishers. These emails solicit article manuscripts, editorial board service, and even ad hoc peer reviews. These ``predatory'' publishers exploit the scholarly publishing process, patterning themselves after legitimate scholarly publishers yet performing little or no peer review and quickly accepting submitted manuscripts and collecting fees from submitting authors. These counterfeit publishers and journals have published much junk science? especially in the field of cosmology? threatening the integrity of the academic record. This paper examines the current state of predatory publishing and advises researchers how to navigate scholarly publishing to best avoid predatory publishers and other scholarly publishing-related perils.

  2. Petro-States - Predatory or Developmental?

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2000-10-01

    Political attention is increasing on the glaring contradiction in most oil-rich countries between natural abundance and economic and social misery. How can it be that oil is not a blessing, but becomes a curse? Although drawing on economic analysis (Dutch disease), the analytical framework established in this report on Angola and Azerbaijan pays special attention to political and institutional factors and concentrates on the role of the state. Selected variables that are likely to decide whether the petro-states become ''predatory'' or ''developmental'' are studied for both countries. The analysis indicates a danger that oil resources will continue to trickle away instead of trickling down to the benefit of the broader Angolan and Azerbaijani population. Concerted action by international oil companies and the Bretton Woods institutions provides the best hope of moving the present political leadership in Angola and Azerbaijan into a developmental direction. (author)

  3. Global patterns in marine predatory fish

    DEFF Research Database (Denmark)

    van Denderen, Pieter Daniël; Lindegren, Martin; MacKenzie, Brian

    2017-01-01

    known. Here, we show how latitudinal differences in predatory fish can essentially be explained by the inflow of energy at the base of the pelagic and benthic food chain. A low productive benthic energy pathway favours large pelagic species, whereas equal productivities support large demersal......Large teleost (bony) fish are a dominant group of predators in the oceans and constitute a major source of food and livelihood for humans. These species differ markedly in morphology and feeding habits across oceanic regions; large pelagic species such as tunas and billfish typically occur...... in the tropics, whereas demersal species of gadoids and flatfish dominate boreal and temperate regions. Despite their importance for fisheries and the structuring of marine ecosystems, the underlying factors determining the global distribution and productivity of these two groups of teleost predators are poorly...

  4. Petro-States - Predatory or Developmental?

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2000-10-01

    Political attention is increasing on the glaring contradiction in most oil-rich countries between natural abundance and economic and social misery. How can it be that oil is not a blessing, but becomes a curse? Although drawing on economic analysis (Dutch disease), the analytical framework established in this report on Angola and Azerbaijan pays special attention to political and institutional factors and concentrates on the role of the state. Selected variables that are likely to decide whether the petro-states become ''predatory'' or ''developmental'' are studied for both countries. The analysis indicates a danger that oil resources will continue to trickle away instead of trickling down to the benefit of the broader Angolan and Azerbaijani population. Concerted action by international oil companies and the Bretton Woods institutions provides the best hope of moving the present political leadership in Angola and Azerbaijan into a developmental direction. (author)

  5. Environmental boundaries of marine cladoceran distributions in the NW Mediterranean: Implications for their expansion under global warming

    KAUST Repository

    Atienza, Dacha

    2016-08-10

    We studied the horizontal and vertical distributions of marine cladocerans across the Catalan Sea shelf (NW Mediterranean) in July and September 2003, and in June and July 2004. At the seasonal scale, Penilia avirostris appears first in June in the southern region, where temperatures are warmer, and its populations develop northward during the summer. Evadne-Pseudevadne did not show a clear pattern, likely because several species were pooled. In 2003 successive heat waves affecting southwestern Europe resulted in surface seawater temperatures about 2 °C higher than usual across the whole study region. These high temperatures were associated with much lower abundance of P. avirostris. Overall, the mesoscale distributions of cladocerans were associated with the presence of low salinity, productive and stratified waters of continental origin, and negatively linked to the intrusion of offshore waters. On the vertical scale P. avirostris was located within or above the thermocline, whereas Evadne-Pseudevadne was much shallower; no evidence of diel migration was detected in either group. Our study provides new insights regarding the environmental limits for marine cladocerans in the NW Mediterranean; in the particular case of P. avirostris that knowledge can define the likely boundaries of its new distributions as it expands poleward under climate change. © 2016 Elsevier B.V.

  6. Environmental boundaries of marine cladoceran distributions in the NW Mediterranean: Implications for their expansion under global warming

    Science.gov (United States)

    Atienza, Dacha; Sabatés, Ana; Isari, Stamatina; Saiz, Enric; Calbet, Albert

    2016-12-01

    We studied the horizontal and vertical distributions of marine cladocerans across the Catalan Sea shelf (NW Mediterranean) in July and September 2003, and in June and July 2004. At the seasonal scale, Penilia avirostris appears first in June in the southern region, where temperatures are warmer, and its populations develop northward during the summer. Evadne-Pseudevadne did not show a clear pattern, likely because several species were pooled. In 2003 successive heat waves affecting southwestern Europe resulted in surface seawater temperatures about 2 °C higher than usual across the whole study region. These high temperatures were associated with much lower abundance of P. avirostris. Overall, the mesoscale distributions of cladocerans were associated with the presence of low salinity, productive and stratified waters of continental origin, and negatively linked to the intrusion of offshore waters. On the vertical scale P. avirostris was located within or above the thermocline, whereas Evadne-Pseudevadne was much shallower; no evidence of diel migration was detected in either group. Our study provides new insights regarding the environmental limits for marine cladocerans in the NW Mediterranean; in the particular case of P. avirostris that knowledge can define the likely boundaries of its new distributions as it expands poleward under climate change.

  7. Genetic and Immunological Comparison of the Cladoceran Parasite Pasteuria ramosa with the Nematode Parasite Pasteuria penetrans▿

    Science.gov (United States)

    Schmidt, Liesbeth M.; Mouton, Laurence; Nong, Guang; Ebert, Dieter; Preston, James F.

    2008-01-01

    Pasteuria penetrans, an obligate endospore-forming parasite of Meloidogyne spp. (root knot nematodes), has been identified as a promising agent for biocontrol of these destructive agricultural crop pests. Pasteuria ramosa, an obligate parasite of water fleas (Daphnia spp.), has been shown to modulate cladoceran populations in natural ecosystems. Selected sporulation genes and an epitope associated with the spore envelope of these related species were compared. The sigE and spoIIAA/spoIIAB genes differentiate the two species to a greater extent than 16S rRNA and may serve as probes to differentiate the species. Single-nucleotide variations were observed in several conserved genes of five distinct populations of P. ramosa, and while most of these variations are silent single-nucleotide polymorphisms, a few result in conservative amino acid substitutions. A monoclonal antibody directed against an adhesin epitope present on P. penetrans P20 endospores, previously determined to be specific for Pasteuria spp. associated with several phytopathogenic nematodes, also detects an epitope associated with P. ramosa endospores. Immunoblotting provided patterns that differentiate P. ramosa from other Pasteuria spp. This monoclonal antibody thus provides a probe with which to detect and discriminate endospores of different Pasteuria spp. The presence of a shared adhesin epitope in two species with such ecologically distant hosts suggests that there is an ancient and ecologically significant recognition process in these endospore-forming bacilli that contributes to the virulence of both species in their respective hosts. PMID:17933927

  8. Genetic and immunological comparison of the cladoceran parasite Pasteuria ramosa with the nematode parasite Pasteuria penetrans.

    Science.gov (United States)

    Schmidt, Liesbeth M; Mouton, Laurence; Nong, Guang; Ebert, Dieter; Preston, James F

    2008-01-01

    Pasteuria penetrans, an obligate endospore-forming parasite of Meloidogyne spp. (root knot nematodes), has been identified as a promising agent for biocontrol of these destructive agricultural crop pests. Pasteuria ramosa, an obligate parasite of water fleas (Daphnia spp.), has been shown to modulate cladoceran populations in natural ecosystems. Selected sporulation genes and an epitope associated with the spore envelope of these related species were compared. The sigE and spoIIAA/spoIIAB genes differentiate the two species to a greater extent than 16S rRNA and may serve as probes to differentiate the species. Single-nucleotide variations were observed in several conserved genes of five distinct populations of P. ramosa, and while most of these variations are silent single-nucleotide polymorphisms, a few result in conservative amino acid substitutions. A monoclonal antibody directed against an adhesin epitope present on P. penetrans P20 endospores, previously determined to be specific for Pasteuria spp. associated with several phytopathogenic nematodes, also detects an epitope associated with P. ramosa endospores. Immunoblotting provided patterns that differentiate P. ramosa from other Pasteuria spp. This monoclonal antibody thus provides a probe with which to detect and discriminate endospores of different Pasteuria spp. The presence of a shared adhesin epitope in two species with such ecologically distant hosts suggests that there is an ancient and ecologically significant recognition process in these endospore-forming bacilli that contributes to the virulence of both species in their respective hosts.

  9. It's like night and day: Diel net-effects on Cercopagidae densities in the Laurentian Great Lakes

    Science.gov (United States)

    Armenio, Patricia M.; Bunnell, David B.; Adams, Jean V.; Watson, Nicole M.; Woelmer, Whitney

    2017-01-01

    In the Laurentian Great Lakes, zooplankters are often sampled using standard ≤153 μm mesh nets without regard to the time of day they are collected. We sampled Cercopagidae during 2013–2014 in northern Lake Huron during day, dusk, and night using two different nets (a 0.5 m wide 153 μm mesh “standard” net and a 0.75 m wide 285 μm mesh “Bythotrephes” net) to determine if there were any differences in their sampled densities. Bythotrephes densities with the standard net were approximately 2.07-fold greater when captured at night than during the day. No time of day bias occurred with the Bythotrephes net. Nighttime Bythotrephes densities did not differ between the two net types. Cercopagis densities did not vary with net type or the time of day in this study, but future work should revisit this result given our low sample size and the low occurrence of Cercopagis in Lake Huron. To reduce bias and calculate accurate density estimates, Cercopagidae should be sampled at night if using a standard net or any time of day with the Bythotrephes net. Given the large impact of invasive predatory cladocerans Bythotrephes longimanus and Cercopagis pengoi on food webs since their invasion in the Laurentian Great Lakes in the 1980s, proper estimation of their densities is essential.

  10. Acute sensitivity of three Cladoceran species to different types of microplastics in combination with thermal stress.

    Science.gov (United States)

    Jaikumar, Gayathri; Baas, Jan; Brun, Nadja R; Vijver, Martina G; Bosker, Thijs

    2018-08-01

    Microplastics (microplastics on freshwater ecosystems, especially under different environmental conditions. In the present study, the sensitivity of two temperate Cladoceran species, Daphnia magna and Daphnia pulex, and a smaller tropical species Ceriodaphnia dubia, to primary microplastics (PMP) and secondary (weathered) microplastics (SMP) was assessed. A prolonged acute toxicity assay (up to 72 or 96 h) was performed at 18°, 22°, and 26 °C, to determine the influence of temperature as an additional stressor and survival data were analysed using toxicokinetic-toxicodynamic (TK-TD) model. Acute sensitivity of D. magna and D. pulex to both PMP and SMP increased sharply with temperature, whereas that of C. dubia remained relatively stable across temperatures. C. dubia was the most sensitive species at 18 °C, followed by D. pulex and D. magna, which were of comparable sensitivity. However, this ranking was reversed at 26 °C as could be seen from the No Effect Concentration (NEC) estimates of the TK-TD model. In addition, SMP and PMP had a similar effect on D. magna and D. pulex, but PMP was more toxic to C. dubia. Effects on survival were strongly time-dependent and became substantially more severe after the standard 48 h test period. Our results indicate that sensitivity to microplastics may differ between species for different types of microplastics, and could be drastically influenced by temperature albeit at high exposure concentrations. Copyright © 2018 Elsevier Ltd. All rights reserved.

  11. Response of Zooplankton to Climate Variability: Droughts Create a Perfect Storm for Cladocerans in Shallow Eutrophic Lakes

    Directory of Open Access Journals (Sweden)

    Gaohua Ji

    2017-10-01

    Full Text Available A major attribute of the Earth’s climate that may be affected by global warming is the amplitude of variability in teleconnections. These global-scale processes involve links between oceanic conditions in one locale and weather in another, often distant, locale. An example is the El Niño Southern Oscillation (ENSO, which can affect rainfall and then the properties of lakes in Europe, Africa, North and South America. It affects rainfall, droughts and the depth of lakes in Florida, USA. It is predicted that the amplitude of variation in the ENSO will increase with global warming and, therefore, droughts will become more severe and periods of rain more intense. We investigated possible effects of climate on the zooplankton in shallow subtropical lakes by studying 16 years of monthly data from six shallow eutrophic lakes located north of Orlando, Florida. Results indicate that water depth and lake volume are tightly coupled with rainfall, as expected. During droughts, when lake depth and volume were greatly reduced, there were intensified cyanobacterial blooms, and the zooplankton shifted towards greater relative biomass of copepods compared to cladocerans. The change of zooplankton was likely due to the intensified selective fish predation in the reduced water volume, and/or selective adverse effects of cyanobacteria on cladocerans. The greatly reduced volume might lead to a ‘perfect storm’ of top-down and bottom-up factors that favor copepods over cladocerans. The mechanism needs further study. Regardless, this study documents a direct link between climate variability and zooplankton composition, and suggests how future changes in climate might affect plankton communities.

  12. CULTIVATION OF CLADOCERAN (CLADOCERA FOR INCREASING PROVISION OF YOUNG-OF-THE-YEAR CARP (CYPRINUS CARPIO WITH NATURAL FEEDS (REVIEW

    Directory of Open Access Journals (Sweden)

    A. Tuchapska

    2014-06-01

    Full Text Available Purpose. Natural feeds are important in pond fish diet because they contain all nutrients necessary for fish growth and development. The share of natural feeds in fish diet has great effect on fish growth and immunity, assimilation of artificial feeds. The main way of assured procurement of natural feeds for fish feeding at different stages of their development is artificial cultivation of aquatic organisms. However, cultivation of natural feeds is not virtually performed in aquaculture enterprises of Ukraine, therefore an analysis of available data on zooplankton cultivation is important for looking for optimal and economically profitable methods of enrichment of pond fish diet with natural feeds. Methodology. Methods of cladoceran cultivation were the object of the study, material for the study – literature data on ways and methods of zooplankton cultivation. Findings. Cultivation of various species of zooplankton is performed for feeding of pond fish on different life stages. Main object of cultivation in aquaculture is Daphnia magna Straus, juvenile forms of which are consumed by fish larvae, while adult organisms are the most valuable for yearlings and older fish. The efficiency of hydrobiont cultivation highly depends on the selected object, containers, where cladocerans are cultivated, optimum conditions, peculiarities of water supply, species, and application of fertilizers and feeds. Originality. The highest production of zooplankton can be obtained when cultivating D. magna in tanks with continuous flow and in net cages installed in ponds under condition of ensuring requirements of the culture in bacterial and algae feeds (due to application of fertilizers and feeding with feeds and microalgae taking into account their presence in water, which is in the tank-cultivator. Practical value. Simplicity of the methods and high efficiency of zooplankton cultivation for preparation of pond fish juveniles is the basis of its wide use in

  13. Body size and predatory performance in wolves: is bigger better?

    Science.gov (United States)

    MacNulty, Daniel R; Smith, Douglas W; Mech, L David; Eberly, Lynn E

    2009-05-01

    1. Large body size hinders locomotor performance in ways that may lead to trade-offs in predator foraging ability that limit the net predatory benefit of larger size. For example, size-related improvements in handling prey may come at the expense of pursuing prey and thus negate any enhancement in overall predatory performance due to increasing size. 2. This hypothesis was tested with longitudinal data from repeated observations of 94 individually known wolves (Canis lupus) hunting elk (Cervus elaphus) in Yellowstone National Park, USA. Wolf size was estimated from an individually based sex-specific growth model derived from body mass measurements of 304 wolves. 3. Larger size granted individual wolves a net predatory advantage despite substantial variation in its effect on the performance of different predatory tasks; larger size improved performance of a strength-related task (grappling and subduing elk) but failed to improve performance of a locomotor-related task (selecting an elk from a group) for wolves > 39 kg. 4. Sexual dimorphism in wolf size also explained why males outperformed females in each of the three tasks considered (attacking, selecting, and killing). 5. These findings support the generalization that bigger predators are overall better hunters, but they also indicate that increasing size ultimately limits elements of predatory behaviour that require superior locomotor performance. We argue that this could potentially narrow the dietary niche of larger carnivores as well as limit the evolution of larger size if prey are substantially more difficult to pursue than to handle.

  14. Body size and predatory performance in wolves: Is bigger better?

    Science.gov (United States)

    MacNulty, D.R.; Smith, D.W.; Mech, L.D.; Eberly, L.E.

    2009-01-01

    Large body size hinders locomotor performance in ways that may lead to trade-offs in predator foraging ability that limit the net predatory benefit of larger size. For example, size-related improvements in handling prey may come at the expense of pursuing prey and thus negate any enhancement in overall predatory performance due to increasing size. 2. This hypothesis was tested with longitudinal data from repeated observations of 94 individually known wolves (Canis lupus) hunting elk (Cervus elaphus) in Yellowstone National Park, USA. Wolf size was estimated from an individually based sex-specific growth model derived from body mass measurements of 304 wolves. 3. Larger size granted individual wolves a net predatory advantage despite substantial variation in its effect on the performance of different predatory tasks; larger size improved performance of a strength-related task (grappling and subduing elk) but failed to improve performance of a locomotor-related task (selecting an elk from a group) for wolves > 39 kg. 4. Sexual dimorphism in wolf size also explained why males outperformed females in each of the three tasks considered (attacking, selecting, and killing). 5. These findings support the generalization that bigger predators are overall better hunters, but they also indicate that increasing size ultimately limits elements of predatory behaviour that require superior locomotor performance. We argue that this could potentially narrow the dietary niche of larger carnivores as well as limit the evolution of larger size if prey are substantially more difficult to pursue than to handle. ?? 2009 British Ecological Society.

  15. on the Population Growth of the Cladoceran Ceriodaphnia quadrangula (O. F. Muller, 1785.

    Directory of Open Access Journals (Sweden)

    Sevgi Savaş

    2015-12-01

    Full Text Available Cladoceran Ceriodaphnia quadrangula (O.F. Muller, 1785’nın populasyon artışı üzerine sıcaklık ve besin (Scenedesmus acuminatus (von Lagerheim R. H. Chodat yoğunluğunun etkisi. Bu çalışmada, Ceriodaphnia quadrangula’nın populasyon artışı üzerine sıcaklık (20, 25 ve 30 ºC ve farklı besin (Scenedesmus acuminatus yoğunluğunun (15,30,45, 60 ve75x104 h/ml etkisi incelenmiştir. Deneme 16 aydınlık:8 saat karanlık ışık uygulamasında gerçekleştirilmiştir. Deneme başında, farklı besin yoğunlukları içeren her bir tüpe 1 adet 24 saatten genç birey konulmuş, birey sayısı ve büyüme hızı 25 gün süre ile belirlenmiştir. En yüksek birey sayısı (21,433±0,750 birey/ml ve büyüme hızı (0,240±0,004 25 ºC’de 45x104 h/ml’de belirlenmiştir. Besin yoğunluğunun artması, Ceriodaphnia quadrangula’nın birey sayısı ve büyüme hızını arttırmıştır. Farklı besin yoğunluklarının birey sayısına etkisi istatistiki olarak önemli (P0,05 olduğu bulunmuştur

  16. Predatory Publishing: An Emerging Threat to the Medical Literature.

    Science.gov (United States)

    Harvey, H Benjamin; Weinstein, Debra F

    2017-02-01

    The quality of medical literature is increasingly threatened by irresponsible publishing, leading to rising retraction rates, irreproducible results, and a flood of inconsequential publications that distract readers from more meaningful scholarship. "Predatory publishers" offer rapid publication with loose peer review, exploiting a system in which faculty seek longer bibliographies to achieve academic promotion. In this Commentary, the authors highlight some of the evidence that this problem exists and suggest actions to address it. Recommendations for protecting the medical literature include preventing predatory journals from being indexed by the National Library of Medicine; encouraging academic promotions committees to ensure that they prioritize value over volume of publications and that faculty understand that priority; excluding publications from predatory journals on curricula vitae and requiring that retractions are included; developing sanctions for repeated retractions or duplicate publications; and convening an expert panel to better elucidate this problem and determine strategies to combat it.

  17. Behind the Spam: A "Spectral Analysis" of Predatory Publishers

    Science.gov (United States)

    Beall, Jeffrey

    2015-08-01

    Most researchers today are bombarded with spam email solicitations from questionable scholarly publishers. These emails solicit article manuscripts, editorial board service, and even ad hoc peer reviews. These "predatory" publishers exploit the scholarly publishing process, patterning themselves after legitimate scholarly publishers yet performing little or no peer review and quickly accepting submitted manuscripts and collecting fees from submitting authors. These counterfeit publishers and journals have published much junk science — especially in the field of cosmology — threatening the integrity of the academic record. This presentation examines the current state of predatory publishing and related scams such as fake impact factors and advises researchers how to navigate scholarly publishing to best avoid predatory publishers and other scholarly publishing-related perils.

  18. Lead exposure potentiates predatory attack behavior in the cat

    International Nuclear Information System (INIS)

    Li Wenjie; Han Shenggao; Gregg, T.R.; Kemp, F.W.Francis W.; Davidow, A.L.; Louria, D.B.; Siegel, Allan; Bogden, J.D.

    2003-01-01

    Epidemiologic studies have demonstrated that environmental lead exposure is associated with aggressive behavior in children; however, numerous confounding variables limit the ability of these studies to establish a causal relationship. The study of aggressive behavior using a validated animal model was used to test the hypothesis that there is a causal relationship between lead exposure and aggression in the absence of confounding variables. We studied the effects of lead exposure on a feline model of aggression: predatory (quiet biting) attack of an anesthetized rat. Five cats were stimulated with a precisely controlled electrical current via electrodes inserted into the lateral hypothalamus. The response measure was the predatory attack threshold current (i.e., the current required to elicit an attack response on 50% of the trials). Blocks of trials were administered in which predatory attack threshold currents were measured three times a week for a total of 6-10 weeks, including before, during, and after lead exposure. Lead was incorporated into cat food 'treats' at doses of 50-150 mg/kg/day. Two of the five cats received a second period of lead exposure. Blood lead concentrations were measured twice a week and were <1, 21-77, and <20 μg/dL prior to, during, and after lead exposure, respectively. The predatory attack threshold decreased significantly during initial lead exposure in three of five cats and increased after the cessation of lead exposure in four of the five cats (P<0.01). The predatory attack thresholds and blood lead concentrations for each cat were inversely correlated (r=-0.35 to -0.74). A random-effects mixed model demonstrated a significant (P=0.0019) negative association between threshold current and blood lead concentration. The data of this study demonstrate that lead exposure enhances predatory aggression in the cat and provide experimental support for a causal relationship between lead exposure and aggressive behavior in humans

  19. Predatory behavior of the land flatworm Notogynaphallia abundans (Platyhelminthes: Tricladida

    Directory of Open Access Journals (Sweden)

    Maria E. T. Prasniski

    2009-12-01

    Full Text Available Land flatworms are carnivorous, mainly predators. However, knowledge on their predatory behavior and prey preference is very scarce. This paucity of data is a limiting factor in the study of their biology and organismal ecology, resulting in a very difficult task to breed them in the laboratory for prolonged periods if prey preference and predation frequency are unknown. We investigated the predatory behavior of Notogynaphallia abundans (Graff, 1899, Geoplaninae, based on laboratory experiments. In order to determine its predatory choices, we offered mollusks, earthworms, arthropods, and other land flatworms. Only land isopods were accepted, with an average consumption of 3.4 individuals per week. Linear regression showed a positive relationship between the number of consumed isopods and the increase/decrease in body mass. Consumption resulting in an increase in body mass was ca. four isopods per week. Predatory behavior, with a mean time-span of 28 min 45 s ± 15 min 47 s, includes encounter and capture of prey, immobilization, handling and feeding. Variation in the duration of this activity in N. abundans is clearly due to variations in the time necessary for transferring the prey from either the anterior or posterior thirds of the body to the mouth, as well as for external digestion and ingestion. In order to capture very active and fast-moving animals such as land isopods, N. abundans employs various strategies, using either the anterior or the posterior body regions to press the prey against the ground or against its own body, thus allowing it to deal with various responses by the prey, and thereby maximizing predatory success. Similar to other flatworms, both physical holding and entrapment in a mucous secretion are of fundamental importance for prey-immobilization. The different strategies employed by land flatworms in their predatory behavior are discussed, and behavioral plasticity in the capture and immobilization of prey in different

  20. Single and combined effects of microcystin- and saxitoxin-producing cyanobacteria on the fitness and antioxidant defenses of cladocerans.

    Science.gov (United States)

    da S Ferrão-Filho, Aloysio; de Abreu S Silva, Daniel; de Oliveira, Taissa A; de Magalhães, Valéria Freitas; Pflugmacher, Stephan; da Silva, Eduardo Mendes

    2017-10-01

    Cyanobacteria produce different toxic compounds that affect animal life, among them hepatotoxins and neurotoxins. Because cyanobacteria are able to produce a variety of toxic compounds at the same time, organisms may be, generally, subjected to their combined action. In the present study, we demonstrate the single and combined effects on cladocerans of cyanobacteria that produce microcystins (hepatotoxins) and saxitoxins (neurotoxins). Animals were exposed (either singly or combined) to 2 strains of cyanobacteria isolated from the same environment (Funil Reservoir, Rio de Janeiro, Brazil). The effects on clearance rate, mobility, survivorship, fecundity, population increase rate (r), and the antioxidant enzymes glutathione-S-transferase (GST) and catalase (CAT) were measured. Cladoceran species showed a variety of responses to cyanobacterial exposures, going from no effect to impairment of swimming movement, lower survivorship, fecundity, and general fitness (r). Animals ingested cyanobacteria in all treatments, although at lower rates than good food (green algae). Antioxidant defense responses were in accordance with fitness responses, suggesting that oxidative stress may be related to such effects. The present study emphasizes the need for testing combined actions of different classes of toxins, because this is often, and most likely, the scenario in a more eutrophic world with global climatic changes. Environ Toxicol Chem 2017;36:2689-2697. © 2017 SETAC. © 2017 SETAC.

  1. Are predatory journals undermining the credibility of science?

    DEFF Research Database (Denmark)

    Frandsen, Tove Faber

    2017-01-01

    as potential poor scientific standards journals. Citations to 124 potential predatory journals and poor scientific standards journals are looked up in Scopus and the citing authors analysed in regards to geographic location, publications and citations. The results show that the characteristics of the citing...

  2. Predatory mites avoid ovipositing near counter-attacking prey

    NARCIS (Netherlands)

    Faraji, F.; Janssen, A.; Sabelis, M.W.

    2001-01-01

    Attacking prey is not without risk; predators may endure counterattackby the prey. Here, we study the oviposition behaviour of a predatory mite(Iphiseius degenerans) in relation to its prey, thewesternflower thrips (Frankliniella occidentalis). This thrips iscapable of killing the eggs of the

  3. Purification and host specificity of predatory halobacteriovorax isolated from seawater

    Science.gov (United States)

    Halobacteriovorax (formerly Bacteriovorax) are small predatory bacteria found in the marine environment and may serve as biocontrol agents against pathogens in fish and shellfish. Four strains of Halobacteriovorax originally isolated in Vibrio parahaemolyticus O3:K6 host cells were separated from t...

  4. Responses of a Rocky Shore Gastropod to the Effluents of Predatory and Non-predatory Crabs: Avoidance and Attraction.

    Science.gov (United States)

    Marko, P B; Palmer, A R

    1991-12-01

    Laboratory experiments revealed that the rocky shore gastropod, Nucella lamellosa (Gmelin), could discriminate between the effluents of predatory and non-predatory crabs. N. lamellosa turned away from seawater that had passed over the large predatory crab, Cancer productus Randall. This avoidance behavior was observed in snails from two localities that, based on differences in shell form, presumably experienced different levels of predation intensity. The scent of the non-predatory crabs Pugettia producta (Randall) and Lopholithodes mandtii Brandt had no effect on the turning behavior of snails from either site. Surprisingly, snails from both sites were attracted to the scent of a small shore crab, Hemigrapsus nudus (Dana), but moved at random in response to a common prey item Balanus glandula Darwin. These results suggest that N. lamellosa can assess from a distance the relative risks posed by different species of crabs, and respond appropriately. The unexpected attraction to H. nudus suggests that N. lamellosa may use this effluent to home in from a distance on potential refugia, because H. nudus are often associated with crevices and the undersides of boulders where N. lamellosa would be less vulnerable to larger predators.

  5. Natural dissolved humic substances increase the lifespan and promote transgenerational resistance to salt stress in the cladoceran Moina macrocopa.

    Science.gov (United States)

    Suhett, Albert L; Steinberg, Christian E W; Santangelo, Jayme M; Bozelli, Reinaldo L; Farjalla, Vinicius F

    2011-07-01

    Evidence has accumulated that humic substances (HS) are not inert biogeochemicals. Rather, they cause stress symptoms and may modulate the life history of aquatic organisms. Nevertheless, it is still not clear how HS interact with additional stressors and if their effects are transgenerational. We tested the interactive effects of HS and salt to cladocerans, discussing their consequences for the persistence in fluctuating environments, such as coastal lagoons. We used life-table experiments to test the effects of natural HS from a polyhumic coastal lagoon (0, 5, 10, 20, 50, and 100 mg dissolved organic carbon (DOC) L(-1)) on the life-history of the cladoceran Moina macrocopa. We further tested the effects of HS (10 mg DOC L(-1)), within and across generations, on the resistance of M. macrocopa to salt stress (5.5 g L(-1)). HS at 5-20 mg DOC L(-1) extended the mean lifespan of M. macrocopa by ~30%. HS also increased body length at maturity by ~4% at 5-50 mg DOC L(-1) and stimulated male offspring production at all tested concentrations. Exposure to HS (even maternal only) alleviated the salt-induced reduction of somatic growth. Co-exposure to HS increased body volume by 12-22% relative to salt-only treatments, while pre-exposure to HS increased body volume by 40-56% in treatments with salt presence, when compared to non-pre-exposed animals. HS at environmentally realistic concentrations, by acting as mild chemical stressors, modify crucial life-history traits of M. macrocopa, favoring its persistence in fluctuating environments. Some of the effects of HS are even transgenerational.

  6. Lead exposure potentiates predatory attack behavior in the cat.

    Science.gov (United States)

    Li, Wenjie; Han, Shenggao; Gregg, Thomas R; Kemp, Francis W; Davidow, Amy L; Louria, Donald B; Siegel, Allan; Bogden, John D

    2003-07-01

    Epidemiologic studies have demonstrated that environmental lead exposure is associated with aggressive behavior in children; however, numerous confounding variables limit the ability of these studies to establish a causal relationship. The study of aggressive behavior using a validated animal model was used to test the hypothesis that there is a causal relationship between lead exposure and aggression in the absence of confounding variables. We studied the effects of lead exposure on a feline model of aggression: predatory (quiet biting) attack of an anesthetized rat. Five cats were stimulated with a precisely controlled electrical current via electrodes inserted into the lateral hypothalamus. The response measure was the predatory attack threshold current (i.e., the current required to elicit an attack response on 50% of the trials). Blocks of trials were administered in which predatory attack threshold currents were measured three times a week for a total of 6-10 weeks, including before, during, and after lead exposure. Lead was incorporated into cat food "treats" at doses of 50-150 mg/kg/day. Two of the five cats received a second period of lead exposure. Blood lead concentrations were measured twice a week and were cats and increased after the cessation of lead exposure in four of the five cats (Pcat were inversely correlated (r=-0.35 to -0.74). A random-effects mixed model demonstrated a significant (P=0.0019) negative association between threshold current and blood lead concentration. The data of this study demonstrate that lead exposure enhances predatory aggression in the cat and provide experimental support for a causal relationship between lead exposure and aggressive behavior in humans.

  7. Biology and Potential Biogeochemical Impacts of Novel Predatory Flavobacteria

    Science.gov (United States)

    2010-06-01

    the detection of predatory bacteria and to examine the environmental and ecological significance of the functional guild as a whole, a wider range...surfaces. The evidence for each of these ecological niches is distributed heterogeneously across the marine flavobacterial phylogeny . This...Anim Ecol 49: 666-685. 2. Lewis SM (1986) The Role of Herbivorous Fishes in the Organization of a Caribbean Reef Community. Ecological Monographs 56

  8. Individual- and population-level toxicity of the insecticide, spirotetramat and the agricultural adjuvant, Destiny to the Cladoceran, Ceriodaphnia dubia.

    Science.gov (United States)

    Chen, Xue Dong; Stark, John D

    2010-08-01

    The effects of the tetramic acid insecticide, spirotetramat and the agricultural adjuvant, Destiny, were evaluated on the Cladoceran, Ceriodaphnia dubia. These compounds were evaluated separately and as a mixture because they can be applied together for control of certain crop pests and therefore have the potential to enter surface water as a binary mixture. Acute mortality estimates (48 h) were developed followed by chronic exposure (8 days) studies where several population parameters were recorded. Acute LC50 and 95% CL for spirotetramat and Destiny were estimated to be 23.8 (14.5-35.4) and 26.71 (20.8-34.0) mg/l, respectively. Thus, spirotetramat and Destiny were equitoxic to C. dubia at LC50. For the chronic population study, C. dubia populations were exposed to a range of concentrations for spirotetramat and Destiny singly and as a mixture. Each chemical alone reduced the number of founding individuals, offspring/female, final population size, and population growth rate in a concentration-dependent manner. However, exposure to the mixture caused significantly greater reductions in these parameters than either compound alone. These results indicate that agricultural adjuvants and pesticides may cause more damage to aquatic organisms as a mixture than either product alone. Therefore, future evaluations of pesticide effects should consider the effects of adjuvants as a mixture with pesticides when these products are recommended to be applied together for pest control.

  9. Initiation of chromosomal replication in predatory bacterium Bdellovibrio bacteriovorus

    Directory of Open Access Journals (Sweden)

    Lukasz Makowski

    2016-11-01

    Full Text Available Bdellovibrio bacteriovorus is a small Gram-negative predatory bacterium that attacks other Gram-negative bacteria, including many animal, human, and plant pathogens. This bacterium exhibits a peculiar biphasic life cycle during which two different types of cells are produced: non-replicating highly motile cells (the free-living phase and replicating cells (the intracellular-growth phase. The process of chromosomal replication in B. bacteriovorus must therefore be temporally and spatially regulated to ensure that it is coordinated with cell differentiation and cell cycle progression. Recently, B. bacteriovorus has received considerable research interest due to its intriguing life cycle and great potential as a prospective antimicrobial agent. Although we know that chromosomal replication in bacteria is mainly regulated at the initiation step, no data exists about this process in B. bacteriovorus. We report the first characterization of key elements of initiation of chromosomal replication – DnaA protein and oriC region from the predatory bacterium, B. bacteriovorus. In vitro studies using different approaches demonstrate that the B. bacteriovorus oriC (BdoriC is specifically bound and unwound by the DnaA protein. Sequence comparison of the DnaA-binding sites enabled us to propose a consensus sequence for the B. bacteriovorus DnaA box (5’-NN(A/TTCCACA-3’. Surprisingly, in vitro analysis revealed that BdoriC is also bound and unwound by the host DnaA proteins (relatively distantly related from B. bacteriovorus. We compared the architecture of the DnaA–oriC complexes (orisomes in homologous (oriC and DnaA from B. bacteriovorus and heterologous (BdoriC and DnaA from prey, E. coli or P. aeruginosa systems. This work provides important new entry points toward improving our understanding of the initiation of chromosomal replication in this predatory bacterium.

  10. False gold: Safely navigating open access publishing to avoid predatory publishers and journals.

    Science.gov (United States)

    McCann, Terence V; Polacsek, Meg

    2018-04-01

    The aim of this study was to review and discuss predatory open access publishing in the context of nursing and midwifery and develop a set of guidelines that serve as a framework to help clinicians, educators and researchers avoid predatory publishers. Open access publishing is increasingly common across all academic disciplines. However, this publishing model is vulnerable to exploitation by predatory publishers, posing a threat to nursing and midwifery scholarship and practice. Guidelines are needed to help researchers recognize predatory journals and publishers and understand the negative consequences of publishing in them. Discussion paper. A literature search of BioMed Central, CINAHL, MEDLINE with Full Text and PubMed for terms related to predatory publishing, published in the period 2007-2017. Lack of awareness of the risks and pressure to publish in international journals, may result in nursing and midwifery researchers publishing their work in dubious open access journals. Caution should be taken prior to writing and submitting a paper, to avoid predatory publishers. The advantage of open access publishing is that it provides readers with access to peer-reviewed research as soon as it is published online. However, predatory publishers use deceptive methods to exploit open access publishing for their own profit. Clear guidelines are needed to help researchers navigate safely open access publishing. A deeper understanding of the risks of predatory publishing is needed. Clear guidelines should be followed by nursing and midwifery researchers seeking to publish their work in open access journals. © 2017 John Wiley & Sons Ltd.

  11. Format Aside: Applying Beall's Criteria to Assess the Predatory Nature of Both OA and Non-OA Library and Information Science Journals

    Science.gov (United States)

    Olivarez, Joseph D.; Bales, Stephen; Sare, Laura; vanDuinkerken, Wyoma

    2018-01-01

    Jeffrey Beall's blog listing of potential predatory journals and publishers, as well as his "Criteria for Determining Predatory Open-Access (OA) Publishers" are often looked at as tools to help researchers avoid publishing in predatory journals. While these "Criteria" have brought a greater awareness of OA predatory journals,…

  12. Increases of Chamber Height and Base Diameter Have Contrasting Effects on Grazing Rate of Two Cladoceran Species: Implications for Microcosm Studies

    Science.gov (United States)

    Pan, Ying; Zhang, Yunshu; Peng, Yan; Zhao, Qinghua; Sun, Shucun

    2015-01-01

    Aquatic microcosm studies often increase either chamber height or base diameter (to increase water volume) to test spatial ecology theories such as “scale” effects on ecological processes, but it is unclear whether the increase of chamber height or base diameter have the same effect on the processes, i.e., whether the effect of the shape of three-dimensional spaces is significant. We orthogonally manipulated chamber height and base diameter and determined swimming activity, average swimming velocity and grazing rates of the cladocerans Daphnia magna and Moina micrura (on two algae Scenedesmus quadricauda and Chlorella vulgaris; leading to four aquatic algae-cladoceran systems in total) under different microcosm conditions. Across all the four aquatic systems, increasing chamber height at a given base diameter significantly decreased the duration and velocity of horizontal swimming, and it tended to increase the duration but decrease the velocity of vertical swimming. These collectively led to decreases in both average swimming velocity and grazing rate of the cladocerans in the tall chambers (at a given base diameter), in accordance with the positive relationship between average swimming velocity and grazing rate. In contrast, an increase of base diameter at a given chamber height showed contrasting effects on the above parameters. Consistently, at a given chamber volume increasing ratio of chamber height to base diameter decreased the average swimming velocity and grazing rate across all the aquatic systems. In general, increasing chamber depth and base diameter may exert contrasting effects on zooplankton behavior and thus phytoplankton-zooplankton interactions. We suggest that spatial shape plays an important role in determining ecological process and thus should be considered in a theoretical framework of spatial ecology and also the physical setting of aquatic microcosm experiments. PMID:26273836

  13. Comments on cladocerans of crater lakes of the Nevado de Toluca Volcano (Central Mexico), with the description of a new species, Alona manueli sp. nov.

    Science.gov (United States)

    Sinev, Artem Y; Zawisza, Edyta

    2013-01-01

    Cladoceran communities of two lakes of Nevado de Toluca Volcano, Central Mexico, were studied. A new species of Aloninae, Alona manueli sp. nov., is described. It was previously confused with Palearctic Alona intermedia Sars, 1862, but clearly differs from it in the morphology of postabdomen, head shield and head pores, and thoracic limbs. Position of Alona manueli sp. nov. within the genus is unclear, it did not belong to any species-group within Alona s. lato. Other species recorded in the studied lakes are Alona ossiani Sinev, 1998, Alonella pulchella Herrick, 1884, Chydorus belonging to sphaericus-group, Eurycercus longirostris Hann, 1982 and Pleuroxus cf. denticulatus Birge, 1879.

  14. Sub-fossils of cladocerans in the surface sediment of 135 lakes as proxies for community structure of zooplankton, fish abundance and lake temperature

    DEFF Research Database (Denmark)

    Jeppesen, E.; Jensen, J. P.; Lauridsen, T. L.

    2003-01-01

    , which otherwise can be obtained only by long-term frequent contemporary sampling for several years. The contribution of Daphnia to the sum of Daphnia and Bosmina ephippia was negatively correlated with the abundance of fish expressed as catch per night in multi-mesh sized gill nets (CPUE). Yet, region...... to summer mean air temperature, and for Danish lakes also, albeit weakly, to fish CPUE but not to chlorophyll a. Apparently, temperature is the most important factor determining the ratio of parthenogenetic to ephippia producing specimens of Bosmina. We conclude that the sediment record of cladocerans...

  15. Constitutive and Operational Variation of Learning in Foraging Predatory Mites.

    Science.gov (United States)

    Seiter, Michael; Schausberger, Peter

    2016-01-01

    Learning is widely documented across animal taxa but studies stringently scrutinizing the causes of constitutive or operational variation of learning among populations and individuals are scarce. The ability to learn is genetically determined and subject to constitutive variation while the performance in learning depends on the immediate circumstances and is subject to operational variation. We assessed variation in learning ability and performance of plant-inhabiting predatory mites, Amblyseius swirskii, caused by population origin, rearing diet, and type of experience. Using an early learning foraging paradigm, we determined that homogeneous single prey environments did not select for reduced learning ability, as compared to natural prey-diverse environments, whereas a multi-generational pollen diet resulted in loss of learning, as compared to a diet of live prey. Associative learning produced stronger effects than non-associative learning but both types of experience produced persistent memory. Our study represents a key example of environmentally caused variation in learning ability and performance.

  16. Physical evidence of predatory behavior in Tyrannosaurus rex

    Science.gov (United States)

    DePalma, Robert A., II; Burnham, David A.; Martin, Larry D.; Rothschild, Bruce M.; Larson, Peter L.

    2013-07-01

    Feeding strategies of the large theropod, Tyrannosaurus rex, either as a predator or a scavenger, have been a topic of debate previously compromised by lack of definitive physical evidence. Tooth drag and bone puncture marks have been documented on suggested prey items, but are often difficult to attribute to a specific theropod. Further, postmortem damage cannot be distinguished from intravital occurrences, unless evidence of healing is present. Here we report definitive evidence of predation by T. rex: a tooth crown embedded in a hadrosaurid caudal centrum, surrounded by healed bone growth. This indicates that the prey escaped and lived for some time after the injury, providing direct evidence of predatory behavior by T. rex. The two traumatically fused hadrosaur vertebrae partially enclosing a T. rex tooth were discovered in the Hell Creek Formation of South Dakota.

  17. Predatory insects as bioindicators of heavy metal pollution

    International Nuclear Information System (INIS)

    Nummelin, Matti; Lodenius, Martin; Tulisalo, Esa; Hirvonen, Heikki; Alanko, Timo

    2007-01-01

    Heavy metal concentrations of different predatory insects were studied near by a steel factory and from control sites. Waterstriders (Gerridae), dragon fly larvae (Odonata), antlion larvae (Myrmeleontidae) and ants (Formicidae) were analyzed by AAS. In most cases the metal concentrations were higher near the factory, but e.g. waterstriders had higher cadmium concentrations in control area. Discriminant analysis clearly reveals that all these insect groups can be used as heavy metal indicators. However, the commonly used ants were the least effective in indicating the differences between the factory and control sites. Waterstriders are good in detecting differences in iron and manganese, but seem to be poor in accumulating nickel and lead. Antlions are efficient in detecting differences in iron. Antlions and ants are effective in accumulating manganese; as well antlions are efficient in accumulating cadmium. Waterstriders are poor in accumulating lead, but antlions and ants are effective. - Waterstriders, dragon fly larvae, antlion larvae, and ants can be used as heavy metal indicators

  18. Susceptibility of Select Agents to Predation by Predatory Bacteria

    Directory of Open Access Journals (Sweden)

    Riccardo Russo

    2015-12-01

    Full Text Available Select Agents are microorganisms and toxins considered to be exploitable as biological weapons. Although infections by many Select Agents can be treated by conventional antibiotics, the risk of an emerging or engineered drug resistant strain is of great concern. One group of microorganisms that is showing potential to control drug resistant Gram-negative bacteria are the predatory bacteria from the genera Bdellovibrio spp. and Micavibrio spp. In this study, we have examined the ability of Bdellovibrio bacteriovorus (B. bacteriovorus strain 109J, HD100 and Micavibrio aeruginosavorus (M. aeruginosavorus ARL-13 to prey on a variety of Select Agents. Our findings demonstrate that B. bacteriovorus and M. aeruginosavorus are able to prey efficiently on Yersinia pestis and Burkholderia mallei. Modest predation was also measured in co-cultures of B. bacteriovorus and Francisella tularensis. However, neither of the predators showed predation when Burkholderia pseudomallei and Brucella melitensis were used as prey.

  19. Evidence for predatory control of the invasive round goby

    Science.gov (United States)

    Madenjian, C.P.; Stapanian, M.A.; Witzel, L.D.; Einhouse, D.W.; Pothoven, S.A.; Whitford, H.L.

    2011-01-01

    We coupled bioenergetics modeling with bottom trawl survey results to evaluate the capacity of piscivorous fish in eastern Lake Erie to exert predatory control of the invading population of round goby Neogobius melanostomus. In the offshore (>20 m deep) waters of eastern Lake Erie, burbot Lota lota is a native top predator, feeding on a suite of prey fishes. The round goby invaded eastern Lake Erie during the late 1990s, and round goby population size increased dramatically during 1999–2004. According to annual bottom trawl survey results, round goby abundance in offshore waters peaked in 2004, but then declined during 2004–2008. Coincidentally, round goby became an important component of burbot diet beginning in 2003. Using bottom trawling and gill netting, we estimated adult burbot abundance and age structure in eastern Lake Erie during 2007. Diet composition and energy density of eastern Lake Erie burbot were also determined during 2007. This information, along with estimates of burbot growth, burbot mortality, burbot water temperature regime, and energy densities of prey fish from the literature, were incorporated into a bioenergetics model application to estimate annual consumption of round goby by the adult burbot population. Results indicated that the adult burbot population in eastern Lake Erie annually consumed 1,361 metric tons of round goby. Based on the results of bottom trawling, we estimated the biomass of yearling and older round goby in offshore waters eastern Lake Erie during 2007–2008 to be 2,232 metric tons. Thus, the adult burbot population was feeding on round goby at an annual rate equal to 61% of the estimated round goby standing stock. We concluded that the burbot population had high potential to exert predatory control on round goby in offshore waters of eastern Lake Erie.

  20. Predatory Publishing: How to Safely Navigate the Waters of Open Access.

    Science.gov (United States)

    Power, Helen

    2018-03-01

    Open access publishing enables scholarship to be openly accessible to everyone, which has countless benefits. However, the open access movement has opened the door for "predatory publishers" to take advantage of researchers surviving in this publish or perish academic landscape. Predatory journals are becoming increasingly common. Nursing researchers, instructors, and students need to be made aware of the dangers of predatory journals, and they need to know how to identify them. While there are blacklists and whitelists that can be used to aid in decision-making, it is critical to note that these lists can never be entirely up to date. This article incorporates a literature review which provides insights into newer trends in predatory and unethical publishing, including "journal hijacking" and "bogus impact factors". Extensive criteria for assessing emerging or unknown journals is compiled to aid researchers, students, educators, and the public in evaluating open access publications.

  1. Microbial community of predatory bugs of the genus Macrolophus (Hemiptera: Miridae)

    NARCIS (Netherlands)

    Machtelinckx, T.; Van Leeuwen, T.; Van De Wiele, T.; Boon, N.; De Vos, W.H.; Sanchez, J.A.; Nannini, M.; Gheysen, G.; De Clercq, P.

    2012-01-01

    Background: The predatory mirids of the genus Macrolophus are key natural enemies of various economically important agricultural pests. Both M. caliginosus and M. pygmaeus are commercially available for the augmentative biological control of arthropod pests in European greenhouses. The latter

  2. Business Associations as a Defensive Response to Post-Communist Predatory States

    Directory of Open Access Journals (Sweden)

    Paolo Sorbello

    2016-12-01

    Full Text Available Book review Building Business in Post-Communist Russia, Eastern Europe, and Eurasia: Collective Goods, Selective Incentives, and Predatory States, by Dinissa Duvanova, 2013, New York: Cambridge University Press.

  3. Invitation to Speak at a Conference: The Tempting Technique Adopted by Predatory Conferences' Organizers.

    Science.gov (United States)

    Asadi, Amin

    2018-03-08

    In recent years, predatory journals, conferences, and publishers have turned to an inevitable threat in scientific publishing. Researchers, regardless of their disciplines, should be aware of these predators and have to be able to recognize them. The main aim of the present paper is to raise awareness about the growing menace of fake invitations to speak at a scientific conference organized by predatory organizers and publishers. Some subtle signs to identify the fake invitations from the authentic ones have been introduced and discussed.

  4. The Use of Predatory Bacteria to Control Select Pathogens and Treat Respiratory Infections

    Science.gov (United States)

    2015-04-13

    V. et al. The development of a multiplex real-time PCR to quantify Fusarium DNA of trichothecene and fumonisin producing strains in maize ...AND ADDRESS (ES) U.S. Army Research Office P.O. Box 12211 Research Triangle Park, NC 27709-2211 Predatory bacteria, Bdellovibrio bacteriovorus...of Papers published in peer-reviewed journals : Number of Papers published in non peer-reviewed journals : Final Report: The Use of Predatory Bacteria

  5. Ranking predatory journals in dermatology: distinguishing the bad from the ugly.

    Science.gov (United States)

    Tosti, Antonella; Maddy, Austin J

    2017-07-01

    The scientific community depends on high-quality peer-reviewed research, which is being polluted with pseudoscience published in fake journals that have exploited the open-access model. This "predatory publishing" has made its way into the field of dermatology. In a recent study, we identified and listed these journals. The "predatory rate" was calculated for 76 journals in order to rank the journals based on specific criteria associated with unethical publishing. Of the 76 journals, 89.5% were classified as predatory journals and the remaining as journals involved in predatory practices. The field of dermatology is not immune to predatory publishers. This study validates Beall's list as well as other previous studies. Strategies to a solution include spreading awareness throughout academic institutions and dermatology departments as well as avoiding publishers that are involved in predatory practices. However, some journals may be able to make necessary adjustments and become legitimate contributors to the field. © 2017 The International Society of Dermatology.

  6. [Predatory journals: how their publishers operate and how to avoid them].

    Science.gov (United States)

    Kratochvíl, Jiří; Plch, Lukáš

    Authors who publish in scientific or scholarly journals today face the risk of publishing in so-called predatory journals. These journals exploit the noble idea of the Open Access movement, whose goal is to make the latest scientific findings available for free. Predatory journals, unlike the reputable ones working on an Open Access basis, neglect the review process and publish low-quality submissions. The basic attributes of predatory journals are a very quick review process or even none at all, failure to be transparent about author fees for publishing an article, misleading potential authors by imitating the names of well-established journals, and false information on indexing in renowned databases or assigned impact factor. Some preventive measures against publishing in predatory journals or drawing information from them are: a thorough credibility check of the journals webpages, verification of the journals indexing on Bealls List and in the following databases: Web of Science Core Collection, Scopus, ERIH PLUS and DOAJ. Asking other scientists or scholars about their experience with a given journal can also be helpful. Without these necessary steps authors face an increased risk of publishing in a journal of poor quality, which will prevent them from obtaining Research and Development Council points (awarded based on the Information Register of Research & Development results); even more importantly, it may damage their reputation as well as the good name of their home institution in the professional community.Key words: academic writing - medical journals - Open Access - predatory journals - predatory publishers - scientific publications.

  7. Potential predatory and legitimate biomedical journals: can you tell the difference? A cross-sectional comparison.

    Science.gov (United States)

    Shamseer, Larissa; Moher, David; Maduekwe, Onyi; Turner, Lucy; Barbour, Virginia; Burch, Rebecca; Clark, Jocalyn; Galipeau, James; Roberts, Jason; Shea, Beverley J

    2017-03-16

    The Internet has transformed scholarly publishing, most notably, by the introduction of open access publishing. Recently, there has been a rise of online journals characterized as 'predatory', which actively solicit manuscripts and charge publications fees without providing robust peer review and editorial services. We carried out a cross-sectional comparison of characteristics of potential predatory, legitimate open access, and legitimate subscription-based biomedical journals. On July 10, 2014, scholarly journals from each of the following groups were identified - potential predatory journals (source: Beall's List), presumed legitimate, fully open access journals (source: PubMed Central), and presumed legitimate subscription-based (including hybrid) journals (source: Abridged Index Medicus). MEDLINE journal inclusion criteria were used to screen and identify biomedical journals from within the potential predatory journals group. One hundred journals from each group were randomly selected. Journal characteristics (e.g., website integrity, look and feel, editors and staff, editorial/peer review process, instructions to authors, publication model, copyright and licensing, journal location, and contact) were collected by one assessor and verified by a second. Summary statistics were calculated. Ninety-three predatory journals, 99 open access, and 100 subscription-based journals were analyzed; exclusions were due to website unavailability. Many more predatory journals' homepages contained spelling errors (61/93, 66%) and distorted or potentially unauthorized images (59/93, 63%) compared to open access journals (6/99, 6% and 5/99, 5%, respectively) and subscription-based journals (3/100, 3% and 1/100, 1%, respectively). Thirty-one (33%) predatory journals promoted a bogus impact metric - the Index Copernicus Value - versus three (3%) open access journals and no subscription-based journals. Nearly three quarters (n = 66, 73%) of predatory journals had editors or

  8. Constitutive and Operational Variation of Learning in Foraging Predatory Mites.

    Directory of Open Access Journals (Sweden)

    Michael Seiter

    Full Text Available Learning is widely documented across animal taxa but studies stringently scrutinizing the causes of constitutive or operational variation of learning among populations and individuals are scarce. The ability to learn is genetically determined and subject to constitutive variation while the performance in learning depends on the immediate circumstances and is subject to operational variation. We assessed variation in learning ability and performance of plant-inhabiting predatory mites, Amblyseius swirskii, caused by population origin, rearing diet, and type of experience. Using an early learning foraging paradigm, we determined that homogeneous single prey environments did not select for reduced learning ability, as compared to natural prey-diverse environments, whereas a multi-generational pollen diet resulted in loss of learning, as compared to a diet of live prey. Associative learning produced stronger effects than non-associative learning but both types of experience produced persistent memory. Our study represents a key example of environmentally caused variation in learning ability and performance.

  9. Compensatory growth following transient intraguild predation risk in predatory mites.

    Science.gov (United States)

    Walzer, Andreas; Lepp, Natalia; Schausberger, Peter

    2015-05-01

    Compensatory or catch-up growth following growth impairment caused by transient environmental stress, due to adverse abiotic factors or food, is widespread in animals. Such growth strategies commonly balance retarded development and reduced growth. They depend on the type of stressor but are unknown for predation risk, a prime selective force shaping life history. Anti-predator behaviours by immature prey typically come at the cost of reduced growth rates with potential negative consequences on age and size at maturity. Here, we investigated the hypothesis that transient intraguild predation (IGP) risk induces compensatory or catch-up growth in the plant-inhabiting predatory mite Phytoseiulus persimilis . Immature P. persimilis were exposed in the larval stage to no, low or high IGP risk, and kept under benign conditions in the next developmental stage, the protonymph. High but not low IGP risk prolonged development of P. persimilis larvae, which was compensated in the protonymphal stage by increased foraging activity and accelerated development, resulting in optimal age and size at maturity. Our study provides the first experimental evidence that prey may balance developmental costs accruing from anti-predator behaviour by compensatory growth.

  10. Versatile aggressive mimicry of cicadas by an Australian predatory katydid.

    Directory of Open Access Journals (Sweden)

    David C Marshall

    Full Text Available BACKGROUND: In aggressive mimicry, a predator or parasite imitates a signal of another species in order to exploit the recipient of the signal. Some of the most remarkable examples of aggressive mimicry involve exploitation of a complex signal-response system by an unrelated predator species. METHODOLOGY/PRINCIPAL FINDINGS: We have found that predatory Chlorobalius leucoviridis katydids (Orthoptera: Tettigoniidae can attract male cicadas (Hemiptera: Cicadidae by imitating the species-specific wing-flick replies of sexually receptive female cicadas. This aggressive mimicry is accomplished both acoustically, with tegminal clicks, and visually, with synchronized body jerks. Remarkably, the katydids respond effectively to a variety of complex, species-specific Cicadettini songs, including songs of many cicada species that the predator has never encountered. CONCLUSIONS/SIGNIFICANCE: We propose that the versatility of aggressive mimicry in C. leucoviridis is accomplished by exploiting general design elements common to the songs of many acoustically signaling insects that use duets in pair-formation. Consideration of the mechanism of versatile mimicry in C. leucoviridis may illuminate processes driving the evolution of insect acoustic signals, which play a central role in reproductive isolation of populations and the formation of species.

  11. Versatile aggressive mimicry of cicadas by an Australian predatory katydid.

    Science.gov (United States)

    Marshall, David C; Hill, Kathy B R

    2009-01-01

    In aggressive mimicry, a predator or parasite imitates a signal of another species in order to exploit the recipient of the signal. Some of the most remarkable examples of aggressive mimicry involve exploitation of a complex signal-response system by an unrelated predator species. We have found that predatory Chlorobalius leucoviridis katydids (Orthoptera: Tettigoniidae) can attract male cicadas (Hemiptera: Cicadidae) by imitating the species-specific wing-flick replies of sexually receptive female cicadas. This aggressive mimicry is accomplished both acoustically, with tegminal clicks, and visually, with synchronized body jerks. Remarkably, the katydids respond effectively to a variety of complex, species-specific Cicadettini songs, including songs of many cicada species that the predator has never encountered. We propose that the versatility of aggressive mimicry in C. leucoviridis is accomplished by exploiting general design elements common to the songs of many acoustically signaling insects that use duets in pair-formation. Consideration of the mechanism of versatile mimicry in C. leucoviridis may illuminate processes driving the evolution of insect acoustic signals, which play a central role in reproductive isolation of populations and the formation of species.

  12. Killing the killer: predation between protists and predatory bacteria.

    Science.gov (United States)

    Johnke, Julia; Boenigk, Jens; Harms, Hauke; Chatzinotas, Antonis

    2017-05-01

    Predation by microbes is one of the main drivers of bacterial mortality in the environment. In most ecosystems multiple micropredators compete at least partially for the same bacterial resource. Predatory interactions between these micropredators might lead to shifts within microbial communities. Integrating these interactions is therefore crucial for the understanding of ecosystem functioning. In this study, we investigated the predation between two groups of micropredators, i.e. phagotrophic protists and Bdellovibrio and like organisms (BALOs). BALOs are obligate predators of Gram-negative bacteria. We hypothesised that protists can prey upon BALOs despite the small size and high swimming speed of the latter, which makes them potentially hard to capture. Predation experiments including three protists, i.e. one filter feeder and two interception feeder, showed that BALOs are a relevant prey for these protists. The growth rate on BALOs differed for the respective protists. The filter feeding ciliate was growing equally well on the BALOs and on Escherichia coli, whereas the two flagellate species grew less well on the BALOs compared to E. coli. However, BALOs might not be a favourable food source in resource-rich environments as they are not enabling all protists to grow as much as on bacteria of bigger volume. © FEMS 2017. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  13. The role of methyl salicylate in prey searching behavior of the predatory mite phytoseiulus persimilis.

    Science.gov (United States)

    De Boer, Jetske G; Dicke, Marcel

    2004-02-01

    Many carnivorous arthropods use herbivore-induced plant volatiles to locate their prey. These plant volatiles are blends of up to hundreds of compounds. It is often unknown which compounds in such a complex volatile blend represent the signal to the foraging carnivore. We studied the role of methyl salicylate (MeSA) as part of the volatile blend in the foraging behavior of the predatory mite Phytoseiulus persimilis by using a Y-tube olfactometer. MeSA is one of the compounds released by lima bean, infested with Tetranychus urticae--a prey species of the predatory mite. MeSA attracted satiated predatory mites in a dose-dependent way with optimum attraction at a dose of 0.2 microg. Predatory mites did not discriminate between a prey-induced lima bean volatile blend (that contains MeSA) and a prey-induced volatile blend to which an extra amount of synthetic MeSA had been added. However, they preferred a MeSA-containing volatile blend (induced by T. urticae) to an otherwise similar but MeSA-free blend (induced by jasmonic acid). Adding synthetic MeSA to the MeSA-free blend significantly increased the mites' choice for this odor, suggesting an important role for MeSA. This study is a new step toward unraveling the role of herbivore-induced plant volatiles in the foraging behavior of predatory arthropods.

  14. Beware of the predatory science journal: A potential threat to the integrity of medical research.

    Science.gov (United States)

    Johal, Jaspreet; Ward, Robert; Gielecki, Jerzy; Walocha, Jerzy; Natsis, Kostantinos; Tubbs, R Shane; Loukas, Marios

    2017-09-01

    The issue of predatory journals has become increasingly more prevalent over the past decade, as the open-access model of publishing has gained prominence. Although the open-access model is well intentioned to increase accessibility of biomedical research, it is vulnerable to exploitation by those looking to corrupt medical academia and circumvent ethics and research standards. Predatory journals will achieve publication by either soliciting unsuspecting researchers who have legitimate research but fall victim to these predators or researchers looking to quickly publish their research without a thorough review process. Some features of predatory journals are a quick non-peer-review process, falsely listing or exaggerating the credibility of editorial board members, and either lack of or falsification of institutional affiliations and database listings. These predatory journals are a serious threat to the integrity of medical research, as they will infect the available literature with unsubstantiated articles, and allow low-quality research. A number of steps can be taken to prevent the spread and increase awareness of predatory publishers, and these must be done to maintain the integrity of medical academia. Clin. Anat. 30:767-773, 2017. © 2017Wiley Periodicals, Inc. © 2017 Wiley Periodicals, Inc.

  15. The distribution and abundance of reef-associated predatory fishes on the Great Barrier Reef

    Science.gov (United States)

    Emslie, Michael J.; Cheal, Alistair J.; Logan, Murray

    2017-09-01

    Predatory fishes are important components of coral-reef ecosystems of the Great Barrier Reef (GBR) through both the ecological functions they perform and their high value to recreational and commercial fisheries, estimated at 30 million in 2014. However, management of GBR predatory fish populations is hampered by a lack of knowledge of their distribution and abundance, aside from that of the highly targeted coral trout ( Plectropomus spp. and Variola spp.). Furthermore, there is little information on how these fishes respond to environmental stressors such as coral bleaching, outbreaks of coral-feeding starfishes ( Acanthaster planci) and storms, which limits adaptive management of their populations as the frequency or severity of such natural disturbances increases under climate change. Here, we document the distribution and abundance of 48 species of reef-associated predatory fishes and assess their vulnerability to a range of natural disturbances. There were clear differences in predatory fish assemblages across the continental shelf, but many species were widespread, with few species restricted to either inshore or offshore waters. There was weak latitudinal structure with only a few species restricted to either the northern or southern GBR. On the whole, predatory fishes were surprisingly resistant to the effects of disturbance, with few clear changes in abundance or species richness following 66 documented disturbances of varying magnitudes.

  16. Ultimate Drivers and Proximate Correlates of Polyandry in Predatory Mites.

    Directory of Open Access Journals (Sweden)

    Peter Schausberger

    Full Text Available Polyandry is more widespread than anticipated from Bateman's principle but its ultimate (evolutionary causes and proximate (mechanistic correlates are more difficult to pinpoint than those of polygyny. Here, we combined mating experiments, quantification of reproductive traits and microsatellite genotyping to determine the fitness implications of polyandry in two predatory mite species, where males are highly polygynous (up to 45 fertilized females during life, whereas females range from monandry to various polyandry levels. The medium-level polyandrous (up to eight male mates possible Neoseiulus californicus received clear direct and indirect benefits: multiply mated females produced more offspring with higher survival chances over longer times than singly mated females. In contrast, singly and multiply mated females of the low-level polyandrous (commonly two male mates at maximum Phytoseiulus persimilis produced similar numbers of offspring having similar survival chances. In both species, multiple mating resulted in mixed offspring paternities, opening the chance for indirect fitness benefits such as enhanced genetic compatibility, complementarity and/or variability. However, the female re-mating likelihood and the paternity chance of non-first male mates were lower in P. persimilis than in N. californicus. Regarding proximate factors, in both species first mating duration and female re-mating likelihood were negatively correlated. Based on occasional fertilization failure of first male mates in P. persimilis, and mixed offspring paternities in both species, we argue that fertilization assurance and the chance to gain indirect fitness benefits are the ultimate drivers of polyandry in P. persimilis, whereas those of N. californicus are higher offspring numbers coupled with enhanced offspring viability and possibly other indirect fitness benefits. Overall, the adaptive significance and proximate events well reflected the polyandry levels. Our

  17. Ultimate Drivers and Proximate Correlates of Polyandry in Predatory Mites.

    Science.gov (United States)

    Schausberger, Peter; Patiño-Ruiz, J David; Osakabe, Masahiro; Murata, Yasumasa; Sugimoto, Naoya; Uesugi, Ryuji; Walzer, Andreas

    2016-01-01

    Polyandry is more widespread than anticipated from Bateman's principle but its ultimate (evolutionary) causes and proximate (mechanistic) correlates are more difficult to pinpoint than those of polygyny. Here, we combined mating experiments, quantification of reproductive traits and microsatellite genotyping to determine the fitness implications of polyandry in two predatory mite species, where males are highly polygynous (up to 45 fertilized females during life), whereas females range from monandry to various polyandry levels. The medium-level polyandrous (up to eight male mates possible) Neoseiulus californicus received clear direct and indirect benefits: multiply mated females produced more offspring with higher survival chances over longer times than singly mated females. In contrast, singly and multiply mated females of the low-level polyandrous (commonly two male mates at maximum) Phytoseiulus persimilis produced similar numbers of offspring having similar survival chances. In both species, multiple mating resulted in mixed offspring paternities, opening the chance for indirect fitness benefits such as enhanced genetic compatibility, complementarity and/or variability. However, the female re-mating likelihood and the paternity chance of non-first male mates were lower in P. persimilis than in N. californicus. Regarding proximate factors, in both species first mating duration and female re-mating likelihood were negatively correlated. Based on occasional fertilization failure of first male mates in P. persimilis, and mixed offspring paternities in both species, we argue that fertilization assurance and the chance to gain indirect fitness benefits are the ultimate drivers of polyandry in P. persimilis, whereas those of N. californicus are higher offspring numbers coupled with enhanced offspring viability and possibly other indirect fitness benefits. Overall, the adaptive significance and proximate events well reflected the polyandry levels. Our study provides a

  18. Anti-predatory particle swarm optimization: Solution to nonconvex economic dispatch problems

    Energy Technology Data Exchange (ETDEWEB)

    Selvakumar, A. Immanuel [Department of Electrical and Electronics Engineering, Karunya Institute of Technology and Sciences, Coimbatore 641114, Tamilnadu (India); Thanushkodi, K. [Department of Electronics and Instrumentation Engineering, Government College of Technology, Coimbatore 641013, Tamilnadu (India)

    2008-01-15

    This paper proposes a new particle swarm optimization (PSO) strategy namely, anti-predatory particle swarm optimization (APSO) to solve nonconvex economic dispatch problems. In the classical PSO, the movement of a particle (bird) is governed by three behaviors: inertial, cognitive and social. The cognitive and social behaviors are the components of the foraging activity, which help the swarm of birds to locate food. Another activity that is observed in birds is the anti-predatory nature, which helps the swarm to escape from the predators. In this work, the anti-predatory activity is modeled and embedded in the classical PSO to form APSO. This inclusion enhances the exploration capability of the swarm. To validate the proposed APSO model, it is applied to two test systems having nonconvex solution spaces. Satisfactory results are obtained when compared with previous approaches. (author)

  19. 40 CFR 180.1101 - Parasitic (parasitoid) and predatory insects; exemption from the requirement of a tolerance.

    Science.gov (United States)

    2010-07-01

    ... insects; exemption from the requirement of a tolerance. 180.1101 Section 180.1101 Protection of... predatory insects; exemption from the requirement of a tolerance. Parasitic (parasitoid) and predatory insects are exempted from the requirement of a tolerance for residues when they are used in accordance...

  20. Impacts of 2 species of predatory Reduviidae on bagworms in oil palm plantations

    Institute of Scientific and Technical Information of China (English)

    Syari Jamian; Ahmad Norhisham; Amal Ghazali; Azlina Zakaria; Badrul Azhar

    2017-01-01

    Integrated pest management (IPM) is widely practiced in commercial oil palm agriculture.This management system is intended to minimize the number of attacks by pest insects such as bagworms on crops,as well as curb economic loss with less dependency on chemical pesticides.One practice in IPM is the use of biological control agents such as predatory insects.In this study,we assessed the response of predatory natural enemies to pest outbreak and water stress,and document the habitat associations of potential pest predators.The abundances of 2 predatory insect species,namely Sycanus dichotomus and Cosmolestes picticeps (Hemiptera:Reduviidae),were compared bagworm outbreak sites and nonoutbreak sites within oil palm plantations.We also examined habitat characteristics that influence the abundances of both predatory species.We found that the abundance of C.picticeps was significantly higher in bagworm outbreak sites than in nonoutbreak sites.There were no significant differences in the abundance of S.dichotomus among outbreak and non-outbreak sites.Both species responded negatively to water stress in oil palm plantations.Concerning the relationship between predatory insect abundance and in situ habitat quality characteristics,our models explained 46.36% of variation for C.picticeps and 23.17% of variation for S.dichotomus.Both species of predatory insects thrived from the planting of multiple beneficial plants in oil palm plantations.The results suggest that C.picticeps can be used as a biological agent to control bagworm populations in oil palm plantations,but S.dichotomus has no or little potential for such ecosystem service.

  1. The surge of predatory open-access in neurosciences and neurology.

    Science.gov (United States)

    Manca, Andrea; Martinez, Gianluca; Cugusi, Lucia; Dragone, Daniele; Dvir, Zeevi; Deriu, Franca

    2017-06-14

    Predatory open access is a controversial publishing business model that exploits the open-access system by charging publication fees in the absence of transparent editorial services. The credibility of academic publishing is now seriously threatened by predatory journals, whose articles are accorded real citations and thus contaminate the genuine scientific records of legitimate journals. This is of particular concern for public health since clinical practice relies on the findings generated by scholarly articles. Aim of this study was to compile a list of predatory journals targeting the neurosciences and neurology disciplines and to analyze the magnitude and geographical distribution of the phenomenon in these fields. Eighty-seven predatory journals operate in neurosciences and 101 in neurology, for a total of 2404 and 3134 articles issued, respectively. Publication fees range 521-637 USD, much less than those charged by genuine open-access journals. The country of origin of 26.0-37.0% of the publishers was impossible to determine due to poor websites or provision of vague or non-credible locations. Of the rest 35.3-42.0% reported their headquarters in the USA, 19.0-39.2% in India, 3.0-9.8% in other countries. Although calling themselves "open-access", none of the journals retrieved was listed in the Directory of Open Access Journals. However, 14.9-24.7% of them were found to be indexed in PubMed and PubMed Central, which raises concerns on the criteria for inclusion of journals and publishers imposed by these popular databases. Scholars in the neurosciences are advised to use all the available tools to recognize predatory practices and avoid the downsides of predatory journals. Copyright © 2017 IBRO. Published by Elsevier Ltd. All rights reserved.

  2. A Fundamental Step in IPM on Grapevine: Evaluating the Side Effects of Pesticides on Predatory Mites

    Directory of Open Access Journals (Sweden)

    Alberto Pozzebon

    2015-10-01

    Full Text Available Knowledge on side effects of pesticides on non-target beneficial arthropods is a key point in Integrated Pest Management (IPM. Here we present the results of four experiments conducted in vineyards where the effects of chlorpyrifos, thiamethoxam, indoxacarb, flufenoxuron, and tebufenozide were evaluated on the generalist predatory mites Typhlodromus pyri Scheuten and Amblyseius andersoni (Chant, key biocontrol agents of herbivorous mites on grapevines. Results show that indoxacarb and tebufenozide had a low impact on the predatory mites considered here, while a significant impact was observed for chlorpyrifos, flufenoxuron, and thiamethoxam. The information obtained here should be considered in the design of IPM strategies on grapevine.

  3. Invitation to Speak at a Conference: The Tempting Technique Adopted by Predatory Conferences’ Organizers

    DEFF Research Database (Denmark)

    Asadi, Amin

    2018-01-01

    In recent years, predatory journals, conferences, and publishers have turned to an inevitable threat in scientific publishing. Researchers, regardless of their disciplines, should be aware of these predators and have to be able to recognize them. The main aim of the present paper is to raise awar...... awareness about the growing menace of fake invitations to speak at a scientific conference organized by predatory organizers and publishers. Some subtle signs to identify the fake invitations from the authentic ones have been introduced and discussed....

  4. Predatory Pricing: Persaingan Harga Minimarket dan Gadde-Gadde dalam Metafora Cerpen

    Directory of Open Access Journals (Sweden)

    Andi Sri Wahyuni

    2015-08-01

    Full Text Available This article is aimed to explore the determination of agressive cost of product (predatory pricing used by minimarket. Short story metaphor by Eka Kurniawan, “Kisah Seorang Kawan” as methodology. The “father” figure in this story has similiar condition with enterpreneur of gadde-gadde. The story begins with the attendant of “the rich merchant” who represent the arrival of minimarket in housing area at Makassar. Through the short story, strategy of predatory pricing could attract customer to move from gadde-gadde to minimarket. Finally, these changes could diminish small businesses which are become the primary economic sector.

  5. Factitious prey and artificial diets for predatory lady beetles: current situation, obstacles, and approaches for improvement

    Science.gov (United States)

    Predatory lady beetles (Coleoptera: Coccinellidae) are important natural enemies of many pests in crop ecosystems throughout the world. Although several species are currently mass-reared and sold by biocontrol companies, there is an urgent need to reduce rearing costs. Cost effective mass rearing of...

  6. The Role of Militia, Predatory State Authorities, and Rogue Capital in ...

    International Development Research Centre (IDRC) Digital Library (Canada)

    The Role of Militia, Predatory State Authorities, and Rogue Capital in the Horn of Africa. The nature of the relationship between militias, rogue capital, and the state in the Horn of Africa is largely unknown. New research will map militia presence in the region, and generate knowledge that could be used to develop national ...

  7. Leaf domatia do not affect population dynamics of the predatory mite Iphiseiodes zuluagai

    NARCIS (Netherlands)

    Ferreira, J.A.M.; Pallini, A.; Oliveira, C.L.; Sabelis, M.W.; Janssen, A.

    2010-01-01

    Leaves of plants of several families possess small cavities or tufts of hair where leaf veins bifurcate. These so-called acarodomatia are usually inhabited by predatory and fungivorous mites, which utilize domatia as shelter against adverse conditions or against other predators and cannibals. Plants

  8. The predatory mite Phytoseiulus persimilis does not perceive odor mixtures as strictly elemental objects

    NARCIS (Netherlands)

    van Wijk, M.; de Bruijn, P.J.A.; Sabelis, M.W.

    2010-01-01

    Phytoseiulus persimilis is a predatory mite that in absence of vision relies on the detection of herbivore-induced plant odors to locate its prey, the two-spotted spider-mite Tetranychus urticae. This herbivorous prey is feeding on leaves of a wide variety of plant species in different families. The

  9. Innate responses of the predatory mite Phytoseiulus persimilis to a herbivore-induced plant volatile

    NARCIS (Netherlands)

    Sznajder, B.; Sabelis, M.W.; Egas, M.

    2011-01-01

    The responses of the predatory mite P. persimilis to herbivore-induced plant volatiles are at least partly genetically determined. Thus, there is potential for the evolution of this behaviour by natural selection. We tested whether distinct predator genotypes with contrasting responses to a specific

  10. Potential long-term storage of the predatory mite Phytoseiulus persimilis

    Science.gov (United States)

    Increasing the ability to store mass-reared natural enemies during periods or seasons of low demand is a critical need of the biocontrol industry. We tested the hypothesis that cryoprotectant or carbohydrate molecules can enhance long-term cold storage of a predatory mite Phytoseiulus persimilis At...

  11. Morphology of the olfactory system in the predatory mite Phytoseiulus persimilis

    NARCIS (Netherlands)

    van Wijk, M.; Wadman, W.J.; Sabelis, M.W.

    2006-01-01

    The predatory mite Phytoseiulus persimilis locates its prey, the two-spotted spider mite, by means of herbivore-induced plant volatiles. The olfactory response to this quantitatively and qualitatively variable source of information is particularly well documented. The mites perform this task with a

  12. When do predatory mites (Phytoseiidae) attack? Understanding their diel and seasonal predation patterns.

    Science.gov (United States)

    Pérez-Sayas, Consuelo; Aguilar-Fenollosa, Ernestina; Hurtado, Mónica A; Jaques, Josep A; Pina, Tatiana

    2017-06-16

    Predatory mites of the Phytoseiidae family are considered one of the most important groups of natural enemies used in biological control. The behavioral patterns of arthropods can differ greatly daily and seasonally; however, there is a lack of literature related to Phytoseiidae diel and seasonal predation patterns. The predatory activity of three phytoseiid species (two Tetranychidae-specialists, Phytoseiulus persimilis and Neoseiulus californicus, and one omnivore, Euseius stipulatus) that occur naturally in Spanish citrus orchards was observed under laboratory conditions in winter and summer. The temperature and photoperiod of the climatic chamber where the mites were reared did not change during the experiment. Our study demonstrates that phytoseiids can exhibit diel and seasonal predatory patterns when feeding on Tetranychus urticae (Acari: Tetranychidae). Neoseiulus californicus was revealed to be a nocturnal predator in summer but diurnal in winter. In contrast, P. persimilis activity was maximal during the daytime, and E. stipulatus showed no clear daily predation patterns. The predatory patterns described in this study should be taken into account when designing laboratory studies and also in field samplings, especially when applying molecular techniques to unveil trophic relationships. © 2017 Institute of Zoology, Chinese Academy of Sciences.

  13. Predatory bacteria as natural modulators of Vibrio parahaemolyticus and Vibrio vulnificus in seawater and oysters

    Science.gov (United States)

    This study shows that naturally occurring Vibrio predatory bacteria (VPB) exert a major role in controlling pathogenic vibrios in seawater and shellfish. The growth and persistence of Vibrio parahaemolyticus (Vp) and Vibrio vulnificus (Vv) were assessed in natural seawater and in the Eastern oyster...

  14. Influence of mercury bioaccessibility on exposure assessment associated with consumption of cooked predatory fish in Spain.

    Science.gov (United States)

    Torres-Escribano, Silvia; Ruiz, Antonio; Barrios, Laura; Vélez, Dinoraz; Montoro, Rosa

    2011-04-01

    Predatory fish tend to accumulate high levels of mercury (Hg). Food safety assessment of these fish has been carried out on the raw product. However, the evaluation of the risk from Hg concentrations in raw fish might be modified if cooking and bioaccessibility (the contaminant fraction that solubilises from its matrix during gastrointestinal digestion and becomes available for intestinal absorption) were taken into account. Data on Hg bioaccessibility in raw predatory fish sold in Spain are scarce and no research on Hg bioaccessibility in cooked fish is available. The aim of the present study was to evaluate Hg bioaccessibility in various kinds of cooked predatory fish sold in Spain to estimate their health risk. Both Hg and bioaccessible Hg concentrations were analysed in raw and cooked fish (swordfish, tope shark, bonito and tuna). There were no changes in Hg concentrations during cooking. However, Hg bioaccessibility decreased significantly after cooking (42 ± 26% in raw fish and 26 ± 16% in cooked fish), thus reducing in swordfish and tope shark the Hg concentration to which the human organism would be exposed. In future, cooking and bioaccessibility should be considered in risk assessment of Hg concentrations in predatory fish. Copyright © 2011 Society of Chemical Industry.

  15. Characteristics of Hijacked Journals and Predatory Publishers: Our Observations in the Academic World.

    Science.gov (United States)

    Dadkhah, Mehdi; Maliszewski, Tomasz; Jazi, Mohammad Davarpanah

    2016-06-01

    The academic world today includes hijacked journals and predatory publishers that operate based on a 'pay and publish' model and function for financial reasons only. Here we present lesser known aspects and practices of these journals to researchers, showing the core of the problem. Copyright © 2016 Elsevier Ltd. All rights reserved.

  16. Serotonin Drives Predatory Feeding Behavior via Synchronous Feeding Rhythms in the Nematode Pristionchus pacificus

    Directory of Open Access Journals (Sweden)

    Misako Okumura

    2017-11-01

    Full Text Available Feeding behaviors in a wide range of animals are regulated by the neurotransmitter serotonin, although the exact neural circuits and associated mechanism are often unknown. The nematode Pristionchus pacificus can kill other nematodes by opening prey cuticles with movable teeth. Previous studies showed that exogenous serotonin treatment induces a predatory-like tooth movement and slower pharyngeal pumping in the absence of prey; however, physiological functions of serotonin during predation and other behaviors in P. pacificus remained completely unknown. Here, we investigate the roles of serotonin by generating mutations in Ppa-tph-1 and Ppa-bas-1, two key serotonin biosynthesis enzymes, and by genetic ablation of pharynx-associated serotonergic neurons. Mutations in Ppa-tph-1 reduced the pharyngeal pumping rate during bacterial feeding compared with wild-type. Moreover, the loss of serotonin or a subset of serotonergic neurons decreased the success of predation, but did not abolish the predatory feeding behavior completely. Detailed analysis using a high-speed camera revealed that the elimination of serotonin or the serotonergic neurons disrupted the timing and coordination of predatory tooth movement and pharyngeal pumping. This loss of synchrony significantly reduced the efficiency of successful predation events. These results suggest that serotonin has a conserved role in bacterial feeding and in addition drives the feeding rhythm of predatory behavior in Pristionchus.

  17. Elevating the predatory effect: Sensory-scanning foraging strategy by the lobate ctenophore Mnemiopsis leidyi

    DEFF Research Database (Denmark)

    Colin, Sean P.; MacPherson, Roshena; Gemmell, Brad

    2015-01-01

    The influential predatory role of the lobate comb jellyfish Mnemiopsis leidyi has largely been attributed to the generation of a hydrodynamically silent feeding current to entrain and initiate high encounter rates with prey. However, for high encounter rates to translate to high ingestion rates, ...

  18. Awareness of "predatory" open-access journals among prospective veterinary and medical authors attending scientific writing workshops

    Directory of Open Access Journals (Sweden)

    Mary M Christopher

    2015-08-01

    Full Text Available Authors face many choices when selecting a journal for publication. Prospective authors, especially trainees, may be unaware of predatory online journals or how to differentiate them from legitimate journals. In this study we assessed awareness of open-access and predatory journals among prospective authors attending scientific writing workshops; our long-term goal was to inform educational goals for the workshops. We surveyed participants of writing workshops at veterinary and medical schools and an international conference over a 1-year period. The survey included 14 statements for respondents to indicate agreement level on a Likert-like scale and four questions on awareness of resources about predatory journals; respondents also defined predatory journal. A total of 145 participants completed the survey: 106 (73.1% from veterinary schools and 86 (59.3% graduate students or residents. Fewer faculty (vs trainees agreed that open access was an important factor in deciding where to publish; faculty and postdoctoral researchers were more likely to expect to pay more to publish in an open-access journal. Most respondents (120/145, 82.7% agreed/strongly agreed that the decision to accept a manuscript should not be influenced by publication charges, but 50% (56/112 indicated they didn’t know how publishing costs were supported. Of the 142 respondents who answered, 33 (23.0% indicated awareness of the term predatory journal; 34 (23.9% were aware of the Directory of Open Access Journals; 24 (16.9% were aware of the Science sting article about predatory journals; and 7 (4.8% were aware of Beall’s list. Most (93/144, 64.5% definitions of predatory journals described poor but not predatory journal practices, and some respondents misunderstood the term completely. Mentors should help novice authors to be aware of predatory journals and to distinguish between legitimate and illegitimate open-access journals, thus selecting the best journal for their

  19. Awareness of "Predatory" Open-Access Journals among Prospective Veterinary and Medical Authors Attending Scientific Writing Workshops.

    Science.gov (United States)

    Christopher, Mary M; Young, Karen M

    2015-01-01

    Authors face many choices when selecting a journal for publication. Prospective authors, especially trainees, may be unaware of "predatory" online journals or how to differentiate them from legitimate journals. In this study, we assessed awareness of open-access and predatory journals among prospective authors attending scientific writing workshops; our long-term goal was to inform educational goals for the workshops. We surveyed participants of writing workshops at veterinary and medical schools and an international conference over a 1-year period. The survey included 14 statements for respondents to indicate agreement level on a Likert-like scale and four questions on awareness of resources about predatory journals; respondents also defined "predatory journal." A total of 145 participants completed the survey: 106 (73.1%) from veterinary schools and 86 (59.3%) graduate students or residents. Fewer faculty (vs trainees) agreed that open access was an important factor in deciding where to publish; faculty and postdoctoral researchers were more likely to expect to pay more to publish in an open-access journal. Most respondents (120/145, 82.7%) agreed/strongly agreed that the decision to accept a manuscript should not be influenced by publication charges, but 50% (56/112) indicated that they "didn't know" how publishing costs were supported. Of the 142 respondents who answered, 33 (23.0%) indicated awareness of the term "predatory journal"; 34 (23.9%) were aware of the Directory of Open Access Journals; 24 (16.9%) were aware of the Science "sting" article about predatory journals; and 7 (4.8%) were aware of Beall's list. Most (93/144, 64.5%) definitions of predatory journals described poor but not predatory journal practices, and some respondents misunderstood the term completely. Mentors should help novice authors to be aware of predatory journals and to distinguish between legitimate and illegitimate open-access journals, thus selecting the best journal for their

  20. Military Personnel: DOD's Predatory Lending Report Addressed Mandated Issues, but Support Is Limited for Some Findings and Recommendations

    National Research Council Canada - National Science Library

    Farrell, Brenda S

    2007-01-01

    ... (see the list of related GAO products at the end of this report). In conducting our review, we limited the scope of our work to the types of loans that DOD identified as being predatory in its mandated 2006 report...

  1. Psychological stress on female mice diminishes the developmental potential of oocytes: a study using the predatory stress model.

    Directory of Open Access Journals (Sweden)

    Yu-Xiang Liu

    Full Text Available Although the predatory stress experimental protocol is considered more psychological than the restraint protocol, it has rarely been used to study the effect of psychological stress on reproduction. Few studies exist on the direct effect of psychological stress to a female on developmental competence of her oocytes, and the direct effect of predatory maternal stress on oocytes has not been reported. In this study, a predatory stress system was first established for mice with cats as predators. Beginning 24 h after injection of equine chorionic gonadotropin, female mice were subjected to predatory stress for 24 h. Evaluation of mouse responses showed that the predatory stress system that we established increased anxiety-like behaviors and plasma cortisol concentrations significantly and continuously while not affecting food and water intake of the mice. In vitro experiments showed that whereas oocyte maturation and Sr(2+ activation or fertilization were unaffected by maternal predatory stress, rate of blastocyst formation and number of cells per blastocyst decreased significantly in stressed mice compared to non-stressed controls. In vivo embryo development indicated that both the number of blastocysts recovered per donor mouse and the average number of young per recipient after embryo transfer of blastocysts with similar cell counts were significantly lower in stressed than in unstressed donor mice. It is concluded that the predatory stress system we established was both effective and durative to induce mouse stress responses. Furthermore, predatory stress applied during the oocyte pre-maturation stage significantly impaired oocyte developmental potential while exerting no measurable impact on nuclear maturation, suggesting that cytoplasmic maturation of mouse oocytes was more vulnerable to maternal stress than nuclear maturation.

  2. Predatory behavior of Pseudodorus clavatus (Diptera, Syrphidae on aphids tended by ants

    Directory of Open Access Journals (Sweden)

    Alexandra Bächtold

    2013-12-01

    Full Text Available Predatory behavior of Pseudodorus clavatus (Diptera, Syrphidae on aphids tended by ants. In this study, we examined the interactions between myrmecophilous aphids, their ant-guards and a predatory syrphid species, Pseudodorus clavatus (F.. Larvae of this predator were found in the colonies of three aphid species: Aphis gossypii, A. spiraecola and Toxoptera sp., which were tended by eight ant species, especially Camponotus. Hoverfly larvae managed to infiltrate the aphid colonies and consume nymphs. Predator larvae exhibited inconspicuous movements and were not detected by ants which were commonly observed touching and antennating the larvae they come into contact. These results suggest that behavioral and chemical cues are involved in the infiltration and on the successful predation of syrphids upon aphids.

  3. Race, gender, and statistical representation: predatory mortgage lending and the US community reinvestment movement

    OpenAIRE

    Elvin K Wyly; Mona Atia; Elizabeth Lee; Pablo Mendez

    2007-01-01

    American mortgage markets, once arenas of discrimination by exclusion, now operate as venues of segmentation and discrimination by inclusion: credit is widely available, but its terms vary enormously. One market segment involves sophisticated predatory practices in which certain groups of borrowers are targeted for high-cost credit that strips out home equity and worsens the risks of delinquency, default, and foreclosure. Unfortunately, it has become more difficult to measure inequalities of ...

  4. Optimal strategies and complexity: a theoretical analysis of the anti-predatory behavior of the hare.

    Science.gov (United States)

    Focardi, S; Rizzotto, M

    1999-09-01

    Predator-prey relationships involving rabbits and hares are widely studied at a long-term population level, while the short-term ethological interactions between one predator and one prey are less well documented. We use a physiologically-based model of hare behavior, developed in the framework of artificial intelligence studies, to analyse its sophisticated anti-predatory behavior. The hares use to stand to the fox in order to inform it that its potential prey is alerted. The behavior of the hare is characterized by specific standing and flushing distances. We show that both hare survival probability and body condition depend on habitat cover, as well as on the ability of the predator to approach-undetected-a prey. We study two anti-predatory strategies, one based on the maximization of the survival probability and the other on the maximization of the body conditions of the hare. Despite the fact that the two strategies are not independent, they are characterized by quite different behavioral patterns. Field estimates of flushing and standing distances are consistent with survival maximization. There exists an optimal anti-predatory strategy, characterized by a flushing distance of 20 m and a standing distance of 30 m, which is optimal in a large set of environmental conditions with a sharp fitness advantage with respect to suboptimal strategies. These results improve our understanding of the anti-predatory behavior of the hare and lend credibility to the optimality approach in the behavioral analysis, showing that even for complex organisms, characterized by a large network of internal constraints and feedback, it is possible to identify simple optimal strategies with a large potential for selection.

  5. Response of planktonic cladocerans (Class: Branchiopoda) to short-term changes in environmental variables in the surface waters of the Bay of Biscay

    Science.gov (United States)

    d'Elbée, Jean; Lalanne, Yann; Castège, Iker; Bru, Noelle; D'Amico, Frank

    2014-08-01

    From January 2001 to December 2008, 73 surface plankton samples and 45 vertical profiles of sea temperature, salinity, dissolved oxygen and pH were collected on a monthly basis from a single sampling station located in the Bay of Biscay (43°37N; 1°43W) (North-East Atlantic). Two types of North Atlantic Oscillation (NAO) indexes were included in the data set and submitted to a Canonical Correspondence Analysis and Spearman non-parametric test. Significant breaks and levels in time series were tested using a data segmentation method. The temperature range varies from 11 °C to 25 °C. It begins to rise from April until August and then decline. Low salinity values occur in mid-spring (36 PSU) in autumn. Dissolved oxygen mean values were around 8 mg/l. In summer, when temperature and salinity are high, surface water layer is always accompanied with a significant deoxygenation, and the process reverses in winter. pH mean values range was 7.78-8.33. Seasonal and inter-annual variations of the two NAO indexes are strongly correlated to one another, but do not correlate with any hydrological or biological variable. Five of the seven cladocerans species which are present in the Bay of Biscay were found in this study. There is a strong pattern in species succession throughout the year: Evadne nordmanni is a vernal species, while Penilia avirostris and Pseudevadne tergestina occur mainly in summer and autumn. Evadne spinifera has a maximum abundance in spring, Podon intermedius in autumn, but they both occur throughout the year. However, for some thirty years, the presence of species has tended to become significantly extended throughout the year. During the 2001-2008 period, there was a noticeable decline and even a disappearance of the categories involved in sexual reproduction as well as those involved in parthenogenesis, in favor of non-breeding individuals.

  6. The effects of Copper and Zinc on survival, growth and reproduction of the cladoceran Daphnia longispina: introducing new data in an "old" issue.

    Science.gov (United States)

    Martins, Celso; Jesus, Fátima T; Nogueira, António J A

    2017-11-01

    Metal contamination is still a major environmental issue due to their continuous deposition and persistence. In this work we intended to assess the impact that Copper (Cu) and Zinc (Zn) exert in life-history parameters of Daphnia longispina, a common cladoceran in freshwater environments. Thus, we studied the effects of Cu (20-300 µg/L) and Zn (500-4000 µg/L) on the survival, growth, reproduction, feeding rate and population growth rate of D. longispina. Though survival was only reduced for the highest concentration of each metal, other endpoints were strongly affected by lower concentrations. Growth was affected by both metals, especially in the period 0-7 d, being significant for Cu ≥ 40 µg/L and Zn ≥ 500 µg/L. Indeed, growth endpoints at day 7 (body length and growth rate) were equally or more sensitive than the corresponding endpoints at day 21. The size at first reproduction decreased (significant for Cu ≥ 40 µg/L and Zn ≥ 500 µg/L). Reproduction decreased, which was partially explained by the reduced growth, but additional effects were supported by a direct effect of metals on reproduction (based on the relationship body length-brood size). Reduced growth and reproduction are likely a food mediated effect due to feeding inhibition caused by the metals. Globally, the studied endpoints were affected by Cu and Zn differently, supporting a chemical-specificity of the effects, with Zn causing more pronounced effects than Cu. This work presents an innovative approach to the effects of Cu and Zn to D. longispina, giving a general and comprehensive overview of those effects.

  7. Predatory Capacity in vitro of Native Nematophagous Fungi from Cundinamarca on Gastrointestinal Nematodes of Cattle

    Directory of Open Access Journals (Sweden)

    Dildo Márquez Lara

    2015-12-01

    Full Text Available Dependence and indiscriminate use of chemical anthelmintics as the sole method for controlling gastrointestinal nematodes (GIN of cattle causes problems in the environment, public health, and the productivity of cattle. It is important to develop non-chemical control strategies. Nematophagous fungi can be a viable and promising alternative for the control of these endoparasites. This study aimed to isolate, identify and evaluate in vitro the potential of nematophagous fungi from Cundinamarca on L3 larvae of gastrointestinal nematodes of cattle. 60 soil samples from cattle ranches were sown in Petri boxes containing agar-water for trapping fungi, and three strains of the fungus Arthrobotrys oligospora (L1, XVIII, and XXI and one of Arthrobotrys musiformis (XXIV were identified by morphometric keys. 1 x 106 conidia or chlamydospores of each fungi were used, which faced 100 nematode larvae. Isolate XXIV (A. musiformis showed greater predatory capacity (96.8% than isolates (A. oligospora XVIII, L1, and XXI (69.68, 71.1, and 87.62%, respectively. There were no statistically significant differences (p > 0.05 among the strains with more predatory capacity. This is the first record of in vitro identification and evaluation of the predatory capacity of A. oligospora and A. musiformis, native fungi from Cundinamarca. The results suggest that these fungi could be used as biocontrol agents of nematodes in cattle.

  8. Indirect effect of neem oil on Podisus nigrispinus (Hemiptera, Pentatomidae: biology and predatory capacity

    Directory of Open Access Journals (Sweden)

    Aniele Pianoscki de Campos

    2014-10-01

    Full Text Available This study evaluated the effects on the development and predatory capacity of Podisus nigrispinus fed on Spodoptera frugiperda that have ingested different concentrations of neem oil. The predatory capacity of Podisus nigrispinus was assessed, separating nymphs (fourth instar and adults (males and females. The treatments consisted of S. frugiperda larvae reared in neem oil aqueous solutions (0.077, 0.359 and 0.599%, deltamethrin EC 25 (0.100% and control arranged in a completely randomized design, with ten replicates. Insects were offered three larval densities (one, three and six, in the third or fourth instars. The predated larvae were examined at 24 and 48 hours after the beginning of the experiment. Biological parameters of Podisus nigrispinus were evaluated in groups of ten second-instar nymphs transferred to pots, in five replicates. Insects were offered 2-6 third and/or fourth-instar larvae reared in the same neem oil concentrations in a completely randomized design. The following parameters were evaluated: duration of each nymph stage (days, nymph mortality (%, weight of fifth-instar nymphs (mg, sex ratio, weight of males and females (mg and longevity of unfed adults (days. The predatory capacity of nymphs and adults of Podisus nigrispinus was influenced by the neem oil at the concentrations of 0.359% and 0.599% in the highest density. The concentration of 0.359% lengthened the nymphal stage and the concentration of 0.599% reduced the weight of males.

  9. Predatory activity of Butlerius nematodes and nematophagous fungi against Haemonchus contortus infective larvae

    Directory of Open Access Journals (Sweden)

    Manoel Eduardo da Silva

    Full Text Available Abstract The purpose of this study was to evaluate the predatory activity of the nematode Butlerius spp. and fungal isolates of Duddingtonia flagrans, Clonostachys rosea, Arthrobotrys musiformis and Trichoderma esau against H. contortus infective larvae (L3 in grass pots. Forty-eight plastic gardening pots containing 140 g of sterile soil were used. Panicum spp. grass seeds (200 mg were sown into each pot and individually watered with 10 mL of tap water. Twelve days after seeding, the pots were randomly divided into 6 groups (n=8. Two thousand H. contortus infective larvae (L3 were added to each group. Additionally, the following treatments were established: Group 1 – 2000 Butlerius spp. larvae; group 2 – A. musiformis (1x107 conidia; group 3 – T. esau (1x107 conidia; group 4 – C. rosea (1x107 conidia, group 5 – D. flagrans (1x107conidia and Group 6 – no biological controller (control group. The larval population of H. contortus exposed to Butlerius spp. was reduced by 61.9%. Population reductions of 90.4, 66.7, 61.9 and 85.7% were recorded in the pots containing A. musiformis, T. esau, C. rosea and D. flagrans, respectively. The results of this study indicate that the predatory nematode Butlerius spp. and the assessed fungi display an important predatory activity can be considered suitable potential biological control agents.

  10. Discriminating Between Legitimate and Predatory Open Access Journals: Report from the International Federation for Emergency Medicine Research Committee

    Directory of Open Access Journals (Sweden)

    Bhakti Hansoti

    2016-09-01

    Full Text Available Introduction: Open access (OA medical publishing is growing rapidly. While subscription-based publishing does not charge the author, OA does. This opens the door for “predatory” publishers who take authors’ money but provide no substantial peer review or indexing to truly disseminate research findings. Discriminating between predatory and legitimate OA publishers is difficult. Methods: We searched a number of library indexing databases that were available to us through the University of California, Irvine Libraries for journals in the field of emergency medicine (EM. Using criteria from Jeffrey Beall, University of Colorado librarian and an expert on predatory publishing, and the Research Committee of the International Federation for EM, we categorized EM journals as legitimate or likely predatory. Results: We identified 150 journal titles related to EM from all sources, 55 of which met our criteria for OA (37%, the rest subscription based. Of these 55, 25 (45% were likely to be predatory. We present lists of clearly legitimate OA journals, and, conversely, likely predatory ones. We present criteria a researcher can use to discriminate between the two. We present the indexing profiles of legitimate EM OA journals, to inform the researcher about degree of dissemination of research findings by journal. Conclusion: OA journals are proliferating rapidly. About half in EM are legitimate. The rest take substantial money from unsuspecting, usually junior, researchers and provide no value for true dissemination of findings. Researchers should be educated and aware of scam journals.

  11. Effects of azadirachtin on Tetranychus urticae (Acari: Tetranychidae) and its compatibility with predatory mites (Acari: Phytoseiidae) on strawberry.

    Science.gov (United States)

    Bernardi, Daniel; Botton, Marcos; da Cunha, Uemerson Silva; Bernardi, Oderlei; Malausa, Thibaut; Garcia, Mauro Silveira; Nava, Dori Edson

    2013-01-01

    The spider mite, Tetranychus urticae, is the major strawberry pest in Brazil. The main strategies for its control comprise synthetic acaricides and predatory mites. The recent register of a commercial formula of azadirachtin (Azamax(®) 12 g L(-1) ) can be viable for control of T. urticae. In this work, the effects of azadirachtin on T. urticae and its compatibility with predatory mites Neoseiulus californicus and Phytoseiulus macropilis in the strawberry crop were evaluated. Azadirachtin was efficient against T. urticae, with a mortality rate similar to that of abamectin. In addition, the azadirachtin showed lower biological persistence (7 days) than abamectin (21 days). Azadirachtin did not cause significant mortality of adult predatory mites (N. californicus and P. macropilis), but it did reduce fecundity by 50%. However, egg viability of the azadirachtin treatments was similar to that of the control (>80% viability). The use of azadirachtin and predatory mites is a valuable tool for controlling T. urticae in strawberry crop. Azadirachtin provided effective control of T. urticae and is compatible with the predatory mites N. californicus and P. macropilis. It is an excellent tool to be incorporated into integrated pest management for strawberry crop in Brazil. Copyright © 2012 Society of Chemical Industry.

  12. Does small equal predatory? Analysis of publication charges and transparency of editorial policies in Croatian open access journals.

    Science.gov (United States)

    Stojanovski, Jadranka; Marušić, Ana

    2017-06-15

    We approach the problem of "predatory" journals and publishers from the perspective of small scientific communities and small journals that may sometimes be perceived as "predatory". Among other characteristics of "predatory" journals two most relevant are their business model and the quality of the editorial work. We analysed 444 Croatian open access (OA) journals in the Hrčak (portal of Croatian scientific journals) digital journal repository for the presence of article processing charges as a business model and the transparency of editorial policies. The majority of journals do not charge authors or require submission or article processing charges, which clearly distinguishes them from "predatory" journals. Almost all Hrčak OA journals have publicly available information on editorial boards, including full names and affiliations, and detailed contact information for the editorial office at the Hrčak website. The journal names are unique and cannot be easily confused with another journal or intend to mislead about the journal's origin. While most journals provide information on peer review process, many do not provide guidelines for reviewers or other editorial and publication ethics standards. In order to clearly differentiate themselves from predatory journals, it is not enough for journals from small research communities to operate on non-commercial bases, but also to have transparent editorial policies.

  13. Reduced prefrontal and increased subcortical brain functioning assessed using positron emission tomography in predatory and affective murderers.

    Science.gov (United States)

    Raine, A; Meloy, J R; Bihrle, S; Stoddard, J; LaCasse, L; Buchsbaum, M S

    1998-01-01

    There appear to be no brain imaging studies investigating which brain mechanisms subserve affective, impulsive violence versus planned, predatory violence. It was hypothesized that affectively violent offenders would have lower prefrontal activity, higher subcortical activity, and reduced prefrontal/subcortical ratios relative to controls, while predatory violent offenders would show relatively normal brain functioning. Glucose metabolism was assessed using positron emission tomography in 41 comparisons, 15 predatory murderers, and nine affective murderers in left and right hemisphere prefrontal (medial and lateral) and subcortical (amygdala, midbrain, hippocampus, and thalamus) regions. Affective murderers relative to comparisons had lower left and right prefrontal functioning, higher right hemisphere subcortical functioning, and lower right hemisphere prefrontal/subcortical ratios. In contrast, predatory murderers had prefrontal functioning that was more equivalent to comparisons, while also having excessively high right subcortical activity. Results support the hypothesis that emotional, unplanned impulsive murderers are less able to regulate and control aggressive impulses generated from subcortical structures due to deficient prefrontal regulation. It is hypothesized that excessive subcortical activity predisposes to aggressive behaviour, but that while predatory murderers have sufficiently good prefrontal functioning to regulate these aggressive impulses, the affective murderers lack such prefrontal control over emotion regulation.

  14. The predatory mite Phytoseiulus persimilis does not perceive odor mixtures as strictly elemental objects.

    Science.gov (United States)

    van Wijk, Michiel; de Bruijn, Paulien J A; Sabelis, Maurice W

    2010-11-01

    Phytoseiulus persimilis is a predatory mite that in absence of vision relies on the detection of herbivore-induced plant odors to locate its prey, the two-spotted spider-mite Tetranychus urticae. This herbivorous prey is feeding on leaves of a wide variety of plant species in different families. The predatory mites respond to numerous structurally different compounds. However, typical spider-mite induced plant compounds do not attract more predatory mites than plant compounds not associated with prey. Because the mites are sensitive to many compounds, components of odor mixtures may affect each other's perception. Although the response to pure compounds has been well documented, little is known how interactions among compounds affect the response to odor mixtures. We assessed the relation between the mites' responses elicited by simple mixtures of two compounds and by the single components of these mixtures. The preference for the mixture was compared to predictions under three conceptual models, each based on one of the following assumptions: (1) the responses elicited by each of the individual components can be added to each other; (2) they can be averaged; or (3) one response overshadows the other. The observed response differed significantly from the response predicted under the additive response, average response, and overshadowing response model in 52, 36, and 32% of the experimental tests, respectively. Moreover, the behavioral responses elicited by individual compounds and their binary mixtures were determined as a function of the odor concentration. The relative contribution of each component to the behavioral response elicited by the mixture varied with the odor concentration, even though the ratio of both compounds in the mixture was kept constant. Our experiments revealed that compounds that elicited no response had an effect on the response elicited by binary mixtures that they were part of. The results are not consistent with the hypothesis that P

  15. Analysis of thirteen predatory publishers: a trap for eager-to-publish researchers.

    Science.gov (United States)

    Bolshete, Pravin

    2018-01-01

    To demonstrate a strategy employed by predatory publishers to trap eager-to-publish authors or researchers into submitting their work. This was a case study of 13 potential, possible, or probable predatory scholarly open-access publishers with similar characteristics. Eleven publishers were included from Beall's list and two additional publishers were identified from a Google web search. Each publisher's site was visited and its content analyzed. Publishers publishing biomedical journals were further explored and additional data was collected regarding their volumes, details of publications and editorial-board members. Overall, the look and feel of all 13 publishers was similar including names of publishers, website addresses, homepage content, homepage images, list of journals and subject areas, as if they were copied and pasted. There were discrepancies in article-processing charges within the publishers. None of the publishers identified names in their contact details and primarily included only email addresses. Author instructions were similar across all 13 publishers. Most publishers listed journals of varied subject areas including biomedical journals (12 publishers) covering different geographic locations. Most biomedical journals published none or very few articles. The highest number of articles published by any single biomedical journal was 28. Several editorial-board members were listed across more than one journals, with one member listed 81 times in different 69 journals (i.e. twice in 12 journals). There was a strong reason to believe that predatory publishers may have several publication houses with different names under a single roof to trap authors from different geographic locations.

  16. Engineering a predatory bacterium as a proficient killer agent for intracellular bio-products recovery

    DEFF Research Database (Denmark)

    Martinez, Virginia; Herencias, Cristina; Jurkevitch, Edouard

    2016-01-01

    This work examines the potential of the predatory bacterium Bdellovibrio bacteriovorus HD100, an obligate predator of other Gram-negative bacteria, as an external cell-lytic agent for recovering valuable intracellular bio-products produced by prey cultures. The bio-product targets to be recovered......% of that accumulated by the prey bacteria, even at high biomass concentrations. This innovative downstream process highlights how B. bacteriovorus can be used as a novel, biological lytic agent for the inexpensive, industrial scale recovery of intracellular products from different Gram-negative prey cultures....

  17. Levels of total mercury in predatory fish sold in Canada in 2005

    OpenAIRE

    Dabeka, R.W.; McKenzie, A.D.; Forsyth, D.S.

    2011-01-01

    Total mercury was analysed in 188 samples of predatory fish purchased at the retail level in Canada in 2005. The average concentrations (ng g−1, range) were: sea bass 329 (38–1367), red snapper 148 (36–431), orange roughy 543 (279–974), fresh water trout 55 (20–430), grouper 360 (8–1060), black cod 284 (71–651), Arctic char 37 (28–54), king fish 440 (42–923), tilefish 601 (79–1164) and marlin 854 (125–2346). The Canadian standard for maximum total mercury allowed in the edible portions of fis...

  18. 'Predatory' open access: a longitudinal study of article volumes and market characteristics.

    Science.gov (United States)

    Shen, Cenyu; Björk, Bo-Christer

    2015-10-01

    A negative consequence of the rapid growth of scholarly open access publishing funded by article processing charges is the emergence of publishers and journals with highly questionable marketing and peer review practices. These so-called predatory publishers are causing unfounded negative publicity for open access publishing in general. Reports about this branch of e-business have so far mainly concentrated on exposing lacking peer review and scandals involving publishers and journals. There is a lack of comprehensive studies about several aspects of this phenomenon, including extent and regional distribution. After an initial scan of all predatory publishers and journals included in the so-called Beall's list, a sample of 613 journals was constructed using a stratified sampling method from the total of over 11,000 journals identified. Information about the subject field, country of publisher, article processing charge and article volumes published between 2010 and 2014 were manually collected from the journal websites. For a subset of journals, individual articles were sampled in order to study the country affiliation of authors and the publication delays. Over the studied period, predatory journals have rapidly increased their publication volumes from 53,000 in 2010 to an estimated 420,000 articles in 2014, published by around 8,000 active journals. Early on, publishers with more than 100 journals dominated the market, but since 2012 publishers in the 10-99 journal size category have captured the largest market share. The regional distribution of both the publisher's country and authorship is highly skewed, in particular Asia and Africa contributed three quarters of authors. Authors paid an average article processing charge of 178 USD per article for articles typically published within 2 to 3 months of submission. Despite a total number of journals and publishing volumes comparable to respectable (indexed by the Directory of Open Access Journals) open access

  19. Non-target effects of the entomopathogenic fungus Metarhizium brunneum (BIPESCO 5/F52) on predatory arthropods

    DEFF Research Database (Denmark)

    Campos de Azevedo, Ana Gorete

    females in the presence of M. brunneum revealed that gravid A. aphidimyza are able to perceive the risk posed by M. brunneum and react to that by choosing a pathogen-free site for offspring. In conclusion, non-target effects of M. brunneum on predatory arthropods may be expected. However, knowledge......The overall objective of this PhD thesis was to investigate the interactions that may occur when combining natural enemies of an herbivore. This was done by assessing the non-target effects of the generalist entomopathogenic fungus Metarhizium brunneum on four different predatory arthropods...... of the life cycles of the predatory arthropods and the optimal timing for releasing the natural enemies can reduce the risk of antagonistic interactions. Findings confirm that A. aphidimyza females are able to change their oviposition behavior in the presence of the entomopathogen. It furthermore confirms...

  20. The rhetorical construction of the predatorial virus: a Burkian analysis of nonfiction accounts of the Ebola virus.

    Science.gov (United States)

    Weldon, R A

    2001-01-01

    Over the past 5 years, a new subgenre of horror films, referred to as plague films, has turned our focus to the threat of a hemorrhagic viral pandemic, comparable to the Spanish Flu epidemic of 1916. Based on the Ebola viral outbreaks of 1976, various writers have presented their accounts under the guise of increasing interest and prevention strategies. Disregarding inappropriate health care practices as the cause of these epidemics, accountability is refocused onto the rhetorically constructed, predatory nature of the virus. By employing Burke's theory of dramatism and pentadic analysis, the author examines this rhetorical construction of Ebola as a predatorial virus and its implications for public perceptions of public health endeavors.

  1. Prevalence of sensitization to the predatory mite Amblyseius cucumeris as a new occupational allergen in horticulture.

    Science.gov (United States)

    Groenewoud, G C M; de Graaf in 't Veld, C; vVan Oorschot-van Nes, A J; de Jong, N W; Vermeulen, A M; van Toorenenbergen, A W; Burdorf, A; de Groot, H; Gerth van Wijk, R

    2002-07-01

    Protection against thrips, a common pest in bell pepper horticulture is effectively possible without pesticides by using the commercially available predatory mite Amblyzeius cucumeris (Ac). The prevalence of sensitization to Ac among exposed greenhouse employees and its clinical relevance was studied. Four hundred and seventytwo employees were asked to fill in a questionnaire and were tested on location. Next to RAST, skin prick tests (SPTs) were performed with common inhalant allergens, the storage mite Tyrophagus putrescentiae (Tp) which serves as a temporary food source during the cultivation process and Ac. Furthermore, nasal challenge tests with Ac were carried out in 23 sensitized employees. SPTs positive to Ac were found in 109 employees (23%). Work-related symptoms were reported by 76.1%. Sensitization to Tp was found in 62 employees of whom 48 were also sensitized to Ac. Immunoglobulin (Ig)E-mediated allergy to inhalant allergens appeared to be an important risk factor for sensitization to Ac. Employees with rhinitis symptoms showed a significantly higher response to all Ac doses during the nasal challenge test compared with employees without rhinitis symptoms. The predatory mite Ac is a new occupational allergen in horticulture which can cause an IgE-mediated allergy in exposed employees. It is biologically active on the mucous membranes of the nose and therefore clinically relevant for the development of work-related symptoms.

  2. Side-effects of three pesticides on the predatory mite, Phytoseiulus persimilis (Acari: Phytoseiidae).

    Science.gov (United States)

    Kavousi, A; Talebi, K

    2003-01-01

    Side-effects of three commonly used pesticides in Iran were evaluated on an introduced strain of the predatory mite. Phytoseiulus persimilis Athias-Henriot, reared for about 10 years without exposure to any pesticides. Application of pesticides was carried out either to detached bean leaves using a Potter tower at 1 mg wet deposit per cm2 or by a hand sprayer on bean plants until run off. According to an EPPO decision making scheme, pirimiphos-methyl was found to be harmful (E=90.8%) and heptenophos harmless (E=-3.7%) to the predatory mite in the residual initial toxicity tests. For determination of the hazard class of malathion a field test was found to be necessary (E=59.8%). Categories of 1, 2, 3 were determined for heptenophos, malathion and primiphos-methyl, respectively, using IOBC classification. Despite being harmful, it is possible to use pirimiphos-methyl 10 days before release of P. persimilis. Investigation of the contribution of both lethal and sub-lethal effects to total impact indicated the dominance of lethality in the case of pirimiphos-methyl, while malathion acted by both mechanisms. Heptenophos did not have negative effects on fecundity of P. persimilis but rather caused a higher rate of fecundity in comparison with the control. The mortality found in the heptenophos test was not significantly different from the control.

  3. Horizontal transmission of Paranosema locustae (Microsporidia) in grasshopper populations via predatory natural enemies.

    Science.gov (United States)

    Wang-Peng, Shi; Zheng, Xuan; Jia, Wan-Tong; Li, Ao-Mei; Camara, Ibrahima; Chen, Hong-Xing; Tan, Shu-Qian; Liu, Yi-Qing; Ji, Rong

    2018-04-24

    Paranosema locustae Canning, 1953 (Microsporidia) provides effective control of grasshoppers. While horizontal transmission of P. locustae is known to occur, evidence for the mechanisms of such transmission via predatory natural enemies was found. We conducted a three-year laboratory and field study to assess the potential impact of feces both from grasshoppers Locusta migratoria L. and from their natural enemies on the persistence of P. locustae. We found that P. locustae persisted among grasshopper populations in treated areas and in adjacent untreated areas for up to two years, and the density of grasshoppers decreased in both areas. We showed that healthy grasshoppers could be infected by feeding on food contaminated by feces from their natural enemies. Predators of grasshoppers retained a large number of spores acquired from eating grasshoppers infected with P. locustae. Spores in the feces of the main natural enemy, the beetle Pterostichus gebleri Dejean 1828 in treated area showed clear viability. These results demonstrate that predatory natural enemies are important vectors for this microsporidian disease, and suggest that sustainable transmission and continuing population suppression might be achieved by horizontal transmission through natural enemies, which should be maximized to increase the effectiveness of P. locustae. This article is protected by copyright. All rights reserved.

  4. Predatory and fake scientific journals/publishers: A global outbreak with rising trend: A review

    Directory of Open Access Journals (Sweden)

    Lukić Tin

    2014-01-01

    Full Text Available In recent times some publishers are intensively exploiting the model of open access publishing. During the last several years, studies have shown that there was a substantial increase in the number of fake publishers and hijacked journals. These cyber criminals make money by stealing the identities of legitimate journals and collecting the article processing charges on the papers that are submitted. This is all accomplished by a well developed framework that includes web development steps, intensive e-mail marketing and victim selections. This review article strives to recommend that the Beall's list of predatory publishers and journals should be consulted every time when an author plans to submit scientific work to some of the journals that are indexed by Thomson Reuters/Institute for Scientific Information-ISI and covered by the Journal Citation Report. Also, the authors are advised to be 'up to date' with new information regarding this controversial topic by informing themselves through various web-sites and specialized scientific portals. The review paper itself strives to summarize the most recent investigations on predatory and spurious journals/publishers which affect the entire scientific community, thus representing an outbreak with rising trend not only on national and regional level, but on global level as well.

  5. Diversity and Antimicrobial Potential of Predatory Bacteria from the Peruvian Coastline.

    Science.gov (United States)

    Linares-Otoya, Luis; Linares-Otoya, Virginia; Armas-Mantilla, Lizbeth; Blanco-Olano, Cyntia; Crüsemann, Max; Ganoza-Yupanqui, Mayar L; Campos-Florian, Julio; König, Gabriele M; Schäberle, Till F

    2017-10-12

    The microbiome of three different sites at the Peruvian Pacific coast was analyzed, revealing a lower bacterial biodiversity at Isla Foca than at Paracas and Manglares, with 89 bacterial genera identified, as compared to 195 and 173 genera, respectively. Only 47 of the bacterial genera identified were common to all three sites. In order to obtain promising strains for the putative production of novel antimicrobials, predatory bacteria were isolated from these sampling sites, using two different bait organisms. Even though the proportion of predatory bacteria was only around 0.5% in the here investigated environmental microbiomes, by this approach in total 138 bacterial strains were isolated as axenic culture. 25% of strains showed antibacterial activity, thereby nine revealed activity against clinically relevant methicillin resistant Staphylococcus aureus (MRSA) and three against enterohemorrhagic Escherichia coli (EHEC) strains. Phylogeny and physiological characteristics of the active strains were investigated. First insights into the chemical basis of the antibacterial activity indicated the biosynthetic production of the known compounds ariakemicin, kocurin, naphthyridinomycin, pumilacidins, resistomycin, and surfactin. However, most compounds remained elusive until now. Hence, the obtained results implicate that the microbiome present at the various habitats at the Peruvian coastline is a promising source for heterotrophic bacterial strains showing high potential for the biotechnological production of antibiotics.

  6. Responses of predatory invertebrates to seeding density and plant species richness in experimental tallgrass prairie restorations

    Science.gov (United States)

    Nemec, Kristine T.; Allen, Craig R.; Danielson, Stephen D.; Helzer, Christopher J.

    2014-01-01

    In recent decades, agricultural producers and non-governmental organizations have restored thousands of hectares of former cropland in the central United States with native grasses and forbs. However, the ability of these grassland restorations to attract predatory invertebrates has not been well documented, even though predators provide an important ecosystem service to agricultural producers by naturally regulating herbivores. This study assessed the effects of plant richness and seeding density on the richness and abundance of surface-dwelling (ants, ground beetles, and spiders) and aboveground (ladybird beetles) predatory invertebrates. In the spring of 2006, twenty-four 55 m × 55 m-plots were planted to six replicates in each of four treatments: high richness (97 species typically planted by The Nature Conservancy), at low and high seeding densities, and low richness (15 species representing a typical Natural Resources Conservation Service Conservation Reserve Program mix, CP25), at low and high seeding densities. Ants, ground beetles, and spiders were sampled using pitfall traps and ladybird beetles were sampled using sweep netting in 2007–2009. The abundance of ants, ground beetles, and spiders showed no response to seed mix richness or seeding density but there was a significant positive effect of richness on ladybird beetle abundance. Seeding density had a significant positive effect on ground beetle and spider species richness and Shannon–Weaver diversity. These results may be related to differences in the plant species composition and relative amount of grass basal cover among the treatments rather than richness.

  7. Diversity and Antimicrobial Potential of Predatory Bacteria from the Peruvian Coastline

    Directory of Open Access Journals (Sweden)

    Luis Linares-Otoya

    2017-10-01

    Full Text Available The microbiome of three different sites at the Peruvian Pacific coast was analyzed, revealing a lower bacterial biodiversity at Isla Foca than at Paracas and Manglares, with 89 bacterial genera identified, as compared to 195 and 173 genera, respectively. Only 47 of the bacterial genera identified were common to all three sites. In order to obtain promising strains for the putative production of novel antimicrobials, predatory bacteria were isolated from these sampling sites, using two different bait organisms. Even though the proportion of predatory bacteria was only around 0.5% in the here investigated environmental microbiomes, by this approach in total 138 bacterial strains were isolated as axenic culture. 25% of strains showed antibacterial activity, thereby nine revealed activity against clinically relevant methicillin resistant Staphylococcus aureus (MRSA and three against enterohemorrhagic Escherichia coli (EHEC strains. Phylogeny and physiological characteristics of the active strains were investigated. First insights into the chemical basis of the antibacterial activity indicated the biosynthetic production of the known compounds ariakemicin, kocurin, naphthyridinomycin, pumilacidins, resistomycin, and surfactin. However, most compounds remained elusive until now. Hence, the obtained results implicate that the microbiome present at the various habitats at the Peruvian coastline is a promising source for heterotrophic bacterial strains showing high potential for the biotechnological production of antibiotics.

  8. Publishing Ethics and Predatory Practices: A Dilemma for All Stakeholders of Science Communication.

    Science.gov (United States)

    Gasparyan, Armen Yuri; Yessirkepov, Marlen; Diyanova, Svetlana N; Kitas, George D

    2015-08-01

    Publishing scholarly articles in traditional and newly-launched journals is a responsible task, requiring diligence from authors, reviewers, editors, and publishers. The current generation of scientific authors has ample opportunities for publicizing their research. However, they have to selectively target journals and publish in compliance with the established norms of publishing ethics. Over the past few years, numerous illegitimate or predatory journals have emerged in most fields of science. By exploiting gold Open Access publishing, these journals paved the way for low-quality articles that threatened to change the landscape of evidence-based science. Authors, reviewers, editors, established publishers, and learned associations should be informed about predatory publishing practices and contribute to the trustworthiness of scholarly publications. In line with this, there have been several attempts to distinguish legitimate and illegitimate journals by blacklisting unethical journals (the Jeffrey Beall's list), issuing a statement on transparency and best publishing practices (the Open Access Scholarly Publishers Association's and other global organizations' draft document), and tightening the indexing criteria by the Directory of Open Access Journals. None of these measures alone turned to be sufficient. All stakeholders of science communication should be aware of multiple facets of unethical practices and publish well-checked and evidence-based articles.

  9. State-dependent and odour-mediated anemotatic responses of the predatory mite Phytoseiulus persimilis in a wind tunnel

    NARCIS (Netherlands)

    van Tilborg, M.; Sabelis, M.W.; Roessingh, P.

    2004-01-01

    Anemotaxis in the predatory mite Phytoseiulus persimilis (both well-fed and starved), has previously been studied on a wire grid under slight turbulent airflow conditions yielding weak, yet distinct, gradients in wind speed and odour concentration (Sabelis and Van der Weel 1993). Such conditions

  10. Visual Detection of Speckles in the Fish Xenotoca variata by the Predatory Snake Thamnophis melanogaster in Water of Different Turbidity.

    Science.gov (United States)

    Manjarrez, Javier; Rivas-González, Eric; Venegas-Barrera, Crystian S; Moyaho, Alejandro

    2015-01-01

    Semi-aquatic snakes integrate visual and chemical stimuli, and prey detection and capture success are therefore linked to the display of visual predatory behavior. The snake Thamnophis melanogaster responds preferentially to individuals of the fish Xenotoca variata with a greater number of bright, colorful spots (lateral speckles) compared with those with a smaller number; however, water turbidity can reduce underwater visibility and effect the vulnerability of fish. In this study, we tested whether the presence of iridescent speckles on the flanks of male X. variata interacted with water turbidity to modify the predatory behavior displayed by the snake T. melanogaster. We predicted that in an experimental laboratory test, the snakes would increase the frequency of their predatory behavior to the extent that the water turbidity decreases. The snakes were tested at six different levels of water turbidity, in combination with three categories of male fish (with few, a median number of, or many speckles). The results showed that in a pool with high or zero turbidity, the number of speckles is not a determining factor in the deployment of the predatory behavior of the snake T. melanogaster toward X. variata. Our findings suggest that snakes can view the fish at intermediate percentages of turbidity, but the number of speckles in male X. variata is irrelevant as an interspecific visual signal in environments with insufficient luminosity. The successful capture of aquatic prey is influenced by integration between chemical and visual signals, according to environmental factors that may influence the recognition of individual traits.

  11. Karnyothrips flavipes, a previously unreported predatory thrips of the coffee berry borer: DNA-based gut content analysis

    Science.gov (United States)

    A new predator of the coffee berry borer, Hypothenemus hampei, was found in the coffee growing area of Kisii in Western Kenya. Field observations, laboratory trials and gut content analysis using molecular tools have confirmed the role of the predatory thrips Karnyothrips flavipes Jones (Phlaeothrip...

  12. How to Recognize and Avoid Potential, Possible, or Probable Predatory Open-Access Publishers, Standalone, and Hijacked Journals.

    Science.gov (United States)

    Danevska, Lenche; Spiroski, Mirko; Donev, Doncho; Pop-Jordanova, Nada; Polenakovic, Momir

    2016-11-01

    The Internet has enabled an easy method to search through the vast majority of publications and has improved the impact of scholarly journals. However, it can also pose threats to the quality of published articles. New publishers and journals have emerged so-called open-access potential, possible, or probable predatory publishers and journals, and so-called hijacked journals. It was our aim to increase the awareness and warn scholars, especially young researchers, how to recognize these journals and how to avoid submission of their papers to these journals. Review and critical analysis of the relevant published literature, Internet sources and personal experience, thoughts, and observations of the authors. The web blog of Jeffrey Beall, University of Colorado, was greatly consulted. Jeffrey Beall is a Denver academic librarian who regularly maintains two lists: the first one, of potential, possible, or probable predatory publishers and the second one, of potential, possible, or probable predatory standalone journals. Aspects related to this topic presented by other authors have been discussed as well. Academics should bear in mind how to differentiate between trustworthy and reliable journals and predatory ones, considering: publication ethics, peer-review process, international academic standards, indexing and abstracting, preservation in digital repositories, metrics, sustainability, etc.

  13. Top layer enhances biological ontrol of thrips in ornamentals :"Predatory mites survive better on rich soil cover

    NARCIS (Netherlands)

    Hoogstraten, van K.; Grosman, A.H.

    2014-01-01

    An organic top layer over the soil or substrate can enhance the biological control of thrips in roses and alstroemerias. The top layer contains food for prey mites, which in turn serve as food for predatory mites. In this way the predators survive longer. Thus, as the thrips population increases, an

  14. Identification of volatiles that are used in discrimination between plants infested with prey or nonprey herbivores by a predatory mite

    NARCIS (Netherlands)

    Boer, de J.G.; Posthumus, M.A.; Dicke, M.

    2004-01-01

    Carnivorous arthropods can use herbivore-induced plant volatiles to locate their herbivorous prey. In the field, carnivores are confronted with information from plants infested with herbivores that may differ in their suitability as prey. Discrimination by the predatory mite Phytoseiulus persimilis

  15. Best practices for scholarly authors in the age of predatory journals.

    Science.gov (United States)

    Beall, J

    2016-02-01

    'Continuous effort, not strength or intelligence, is the key to understanding our potential.' Margaret J Wheatley. The focus of any academic or research author is to share his or her findings, and to gain respect and reward for publishing. The ideal journal is one that not only publishes an article quickly but also helps the author to improve the article before publication through peer review, selects only the best research so that the author's article lies alongside other high quality articles, and provides maximum (and long-term) visibility and access to the article. Unfortunately, in the real world, authors need to make tradeoffs between high quality journals, those that work quickly, those that are willing to accept the article and those that provide the best access. Into this mix has come the potential of open access as a means of increasing visibility: journals publish the article without a subscription barrier so anyone, anywhere, can read the article. However, the growth of open access (pushed by institutions, grant bodies and governments as a means of improving human health and knowledge) has come with some unforeseen consequences. In this article, Jeffrey Beall discusses one recent phenomenon that has arisen from the open access movement: that of 'predatory publishers'. These are individuals or companies that use the open access financial system (author pays, rather than library subscribes) to defraud authors and readers by promising reputable publishing platforms but delivering nothing of the sort. They frequently have imaginary editorial boards, do not operate any peer review or quality control, are unclear about payment requirements and opaque about ownership or location, include plagiarised content and publish whatever somebody will pay them to publish. Predatory publishers generally make false promises to authors and behave unethically. They also undermine the scholarly information and publishing environment with a deluge of poor quality, unchecked

  16. Laboratory and field efficacy of Pedalium murex and predatory copepod, Mesocyclops longisetus on rural malaria vector, Anopheles culicifacies

    Directory of Open Access Journals (Sweden)

    Thangadurai Chitra

    2013-04-01

    Full Text Available Objective: To test the potentiality of the leaf extract of Pedalium murex (P. murex and predatory copepod Mesocyclops longisetus (M. longisetus in individual and combination in controlling the rural malarial vector, Anopheles culicifacies (An. culicifacies in laboratory and field studies. Methods: P. murex leaves were collected from in and around Erode, Tamilnadu, India. The active compounds were extracted with 300 mL of methanol for 8 h in a Soxhlet apparatus. Laboratory studies on larvicidal and pupicidal effects of methanolic extract of P. murex tested against the rural malarial vector, An. culicifacies were significant. Results: Evaluated lethal concentrations (LC50 of P. murex extract were 2.68, 3.60, 4.50, 6.44 and 7.60 mg/L for I, II, III, IV and pupae of An. culicifacies, respectively. Predatory copepod, M. longisetus was examined for their predatory efficacy against the malarial vector, An. culicifacies. M. longisetus showed effective predation on the early instar (47% and 36% on I and II instar when compared with the later ones (3% and 1% on III and IV instar. Predatory efficacy of M. longisetus was increased (70% and 45% on I and II instar when the application was along with the P. murex extract. Conclusions: Predator survival test showed that the methanolic extract of P. murex is non-toxic to the predatory copepod, M. longisetus. Experiments were also conducted to evaluate the efficacy of methanolic extract of P. murex and M. longisetus in the direct breeding sites (paddy fields of An. culicifacies. Reduction in larval density was very high and sustained for a long time in combined treatment of P. murex and M. longisetus.

  17. Calcium isotopes offer clues on resource partitioning among Cretaceous predatory dinosaurs.

    Science.gov (United States)

    Hassler, A; Martin, J E; Amiot, R; Tacail, T; Godet, F Arnaud; Allain, R; Balter, V

    2018-04-11

    Large predators are overabundant in mid-Cretaceous continental dinosaur assemblages of North Africa. Such unbalanced ecosystem structure involves, among predatory dinosaurs, typical abelisaurid or carcharodontosaurid theropods co-occurring with long-snouted spinosaurids of debated ecology. Here, we report calcium (Ca) isotope values from tooth enamel (expressed as δ 44/42 Ca) to investigate resource partitioning in mid-Cretaceous assemblages from Niger (Gadoufaoua) and Morocco (Kem Kem Beds). In both assemblages, spinosaurids display a distinct isotopic signature, the most negative in our dataset. This distinct taxonomic clustering in Ca isotope values observed between spinosaurids and other predators provides unambiguous evidence for niche partitioning at the top of the trophic chains: spinosaurids foraged on aquatic environments while abelisaurid and carcharodontosaurid theropods relied almost exclusively on terrestrial resources. © 2018 The Author(s).

  18. Morphology of the olfactory system in the predatory mite Phytoseiulus persimilis.

    Science.gov (United States)

    van Wijk, Michiel; Wadman, Wytse J; Sabelis, Maurice W

    2006-01-01

    The predatory mite Phytoseiulus persimilis locates its prey, the two-spotted spider mite, by means of herbivore-induced plant volatiles. The olfactory response to this quantitatively and qualitatively variable source of information is particularly well documented. The mites perform this task with a peripheral olfactory system that consists of just five putative olfactory sensilla that reside in a dorsal field at the tip of their first pair of legs. The receptor cells innervate a glomerular olfactory lobe just ventral of the first pedal ganglion. We have made a 3D reconstruction of the caudal half of the olfactory lobe in adult females. The glomerular organization as well as the glomerular innervation appears conserved across different individuals. The adult females have, by approximation, a 1:1 ratio of olfactory receptor cells to olfactory glomeruli.

  19. The skull of the giant predatory pliosaur Rhomaleosaurus cramptoni: implications for plesiosaur phylogenetics

    Science.gov (United States)

    Smith, Adam S.; Dyke, Gareth J.

    2008-10-01

    The predatory pliosaurs were among the largest creatures ever to inhabit the oceans, some reaching gigantic proportions greater than 15 m in length. Fossils of this subclade of plesiosaurs are known from sediments all over the world, ranging in age from the Hettangian (approximately 198 Myr) to the Turonian (approximately 92 Myr). However, due to a lack of detailed studies and because only incomplete specimens are usually reported, pliosaur evolution remains poorly understood. In this paper, we describe the three dimensionally preserved skull of the giant Jurassic pliosaur Rhomaleosaurus cramptoni. The first phylogenetic analysis dedicated to in-group relationships of pliosaurs allows us to hypothesise a number of well-supported lineages that correlate with marine biogeography and the palaeoecology of these reptiles. Rhomaleosaurids comprised a short-lived and early diverging lineage within pliosaurs, whose open-water top-predator niche was filled by other pliosaur taxa by the mid-late Jurassic.

  20. Large predatory coral trout species unlikely to meet increasing energetic demands in a warming ocean

    KAUST Repository

    Johansen, J.L.

    2015-09-08

    Increased ocean temperature due to climate change is raising metabolic demands and energy requirements of marine ectotherms. If productivity of marine systems and fisheries are to persist, individual species must compensate for this demand through increasing energy acquisition or decreasing energy expenditure. Here we reveal that the most important coral reef fishery species in the Indo-west Pacific, the large predatory coral trout Plectropomus leopardus (Serranidae), can behaviourally adjust food intake to maintain body-condition under elevated temperatures, and acclimate over time to consume larger meals. However, these increased energetic demands are unlikely to be met by adequate production at lower trophic levels, as smaller prey species are often the first to decline in response to climate-induced loss of live coral and structural complexity. Consequently, ubiquitous increases in energy consumption due to climate change will increase top-down competition for a dwindling biomass of prey, potentially distorting entire food webs and associated fisheries.

  1. Predatory fishes affect trophic cascades and apparent competition in temperate reefs.

    Science.gov (United States)

    Frid, Alejandro; Marliave, Jeff

    2010-08-23

    We provide evidence for a trophic cascade involving apex predators and mesopredators of marine temperate reefs, lingcod and rockfish, respectively. We measured spatio-temporal variation in the relative abundance of lingcod, subadult rockfish and two shrimp groups eaten by rockfish (Pandalus sp. and three smaller-bodied genera aggregated). Lingcod had an indirect positive effect on shrimps, as mediated by the direct negative effects of lingcod on rockfish and of rockfish on shrimps. These top-down effects on shrimps, however, were stronger for Pandalus than for small-bodied shrimps. Further, abundances of Pandalus and small-bodied shrimps were negatively correlated and the latter had a stronger positive effect on rockfish, suggesting that rockfish mediated asymmetrical apparent competition between shrimps. Our results indicate mechanisms by which predatory fishes may influence the structure of marine communities.

  2. Distribution of Po-210 in two species of predatory marine fish from the Brazilian coast

    International Nuclear Information System (INIS)

    Mársico, E.T.; Ferreira, M.S.; São Clemente, S.C.; Gouvea, R.C.S.; Jesus, E.F.O.; Conti, C.C.; Conte Junior, C.A.; Kelecom, A.G.A.C.

    2014-01-01

    Polonium-210 ( 210 Po) concentration was quantified in the muscle tissue and organs of two predatory marine fishes (Genypterus brasiliensis and Cynoscion microlepidotus) from Cabo Frio, Rio de Janeiro, Brazil. The species C. microlepidotus, a benthic carnivore, registered higher 210 Po in its tissue. The organs associated with digestion displayed the maximum radionuclide compared with other organs. The average activity was 2 mBq kg −1 for G. brasiliensis and it was 6 mBq kg −1 for C. microlepidotus. The activity concentrations varied significantly between the species and among organs. -- Highlights: • We analyzed the distribution of 210 Po in two species of predator marine fish. • 210 Po tends to accumulate in some organs, which make this radionuclide radiotoxic. • The consumption of small quantities of fish can represent high potential of 210 Po exposure. • Data about 210 Po bioaccumulation in tropical predator marine fish are limited

  3. Predatory behavior of grizzly bears feeding on elk calves in Yellowstone National Park

    Science.gov (United States)

    French, Steven P.; French, Marilynn G.

    1990-01-01

    Grizzly bears (Ursus arctos horribilis) were observed preying on elk calves (Cervus elaphus) on 60 occasions in Yellowstone National Park, with 29 confirmed kills. Some bears were deliberate predators and effectively preyed on elk calves for short periods each spring, killing up to 1 calf daily. Primary hunting techniques were searching and chasing although some bears used a variety of techniques during a single hunt. They hunted both day and night and preyed on calves in the open and in the woods. Excess killing occurred when circumstances permitted. One bear caught 5 calves in a 15-minute interval. Elk used a variety of antipredator defenses and occasionally attacked predacious bears. The current level of this feeding behavior appears to be greater than previously reported. This is probably related to the increased availability of calves providing a greater opportunity for learning, and the adaptation of a more predatory behavior by some grizzly bears in Yellowstone.

  4. Avoidance response of juvenile Pacific treefrogs to chemical cues of introduced predatory bullfrogs.

    Science.gov (United States)

    Chivers, D P; Wildy, E L; Kiesecker, J M; Blaustein, A R

    2001-08-01

    Bullfrogs (Rana catesbeiana), native to eastern North America, were introduced into Oregon in the 1930's. Bullfrogs are highly efficient predators that are known to eat a variety of prey including other amphibians. In laboratory experiments, we investigated whether juvenile Pacific treefrogs (Hyla regilla) recognize adult bullfrogs as a predatory threat. The ability of prey animals to acquire recognition of an introduced predator has important implications for survival of the prey. We found that treefrogs from a population that co-occurred with bullfrogs showed a strong avoidance of chemical cues of bullfrogs. In contrast, treefrogs from a population that did not co-occur with bullfrogs, did not respond to the bullfrog cues. Additional experiments showed that both populations of treefrogs use chemical cues to mediate predation risk. Treefrogs from both populations avoided chemical alarm cues from injured conspecifics.

  5. Ecological release and venom evolution of a predatory marine snail at Easter Island.

    Science.gov (United States)

    Duda, Thomas F; Lee, Taehwan

    2009-05-20

    Ecological release is coupled with adaptive radiation and ecological diversification yet little is known about the molecular basis of phenotypic changes associated with this phenomenon. The venomous, predatory marine gastropod Conus miliaris has undergone ecological release and exhibits increased dietary breadth at Easter Island. We examined the extent of genetic differentiation of two genes expressed in the venom of C. miliaris among samples from Easter Island, American Samoa and Guam. The population from Easter Island exhibits unique frequencies of alleles that encode distinct peptides at both loci. Levels of divergence at these loci exceed observed levels of divergence observed at a mitochondrial gene region at Easter Island. Patterns of genetic variation at two genes expressed in the venom of this C. miliaris suggest that selection has operated at these genes and contributed to the divergence of venom composition at Easter Island. These results show that ecological release is associated with strong selection pressures that promote the evolution of new phenotypes.

  6. Large predatory coral trout species unlikely to meet increasing energetic demands in a warming ocean

    KAUST Repository

    Johansen, J.L.; Pratchett, M.S.; Messmer, V.; Coker, Darren James; Tobin, A.J.; Hoey, A.S.

    2015-01-01

    Increased ocean temperature due to climate change is raising metabolic demands and energy requirements of marine ectotherms. If productivity of marine systems and fisheries are to persist, individual species must compensate for this demand through increasing energy acquisition or decreasing energy expenditure. Here we reveal that the most important coral reef fishery species in the Indo-west Pacific, the large predatory coral trout Plectropomus leopardus (Serranidae), can behaviourally adjust food intake to maintain body-condition under elevated temperatures, and acclimate over time to consume larger meals. However, these increased energetic demands are unlikely to be met by adequate production at lower trophic levels, as smaller prey species are often the first to decline in response to climate-induced loss of live coral and structural complexity. Consequently, ubiquitous increases in energy consumption due to climate change will increase top-down competition for a dwindling biomass of prey, potentially distorting entire food webs and associated fisheries.

  7. Laboratory evaluation of the effect of Beauveria bassiana on the predatory mite Phytoseiulus persimilis (Acari: Phytoseiidae).

    Science.gov (United States)

    Ullah, Mohammad Shaef; Lim, Un Taek

    2017-09-01

    Tetranychus urticae Koch (Acari: Tetranychidae), a major pest of many agricultural crops, is mainly controlled with chemical acaricides. However, predatory mites and entomopathogens have been proposed as alternative control agents. In this study, the effect of the BotaniGard ® GHA strain of Beauveria bassiana on the survival, longevity, fecundity, and egg hatch rate of the predatory mite Phytoseiulus persimilis Athias-Henriot (Acari: Phytoseiidae) were studied under laboratory conditions. When B. bassiana was applied directly to P. persimilis eggs at a concentration of 1×10 8 conidia/ml, corrected hatchability was less than 5%, and the corrected mortality of nymphs and adults was not significantly different from control 10days after treatment. Phytoseiulus persimilis nymphs that hatched from treated eggs showed no significant change in their development time, adult female longevity, hatch rate, survival rates over time, or offspring sex ratio. However, significant negative effects on fecundity and life table parameters (net reproductive rate, intrinsic rate of natural increase, mean generation time, finite rate of increase, and doubling time) were found when B. bassiana was applied to the adult stage. Spraying B. bassiana at 1×10 8 conidia/ml on newly emerged adults of P. persimilis caused 44% reduction in the oviposition period, 26% in adult longevity, and 63% in fecundity. Due to these negative effects, B. bassiana should be used with careful adjustment of application timing (first spray B. bassiana and then release P. persimilis) to supplement biological mite control systems using P. persimilis. Copyright © 2017 Elsevier Inc. All rights reserved.

  8. Repeated Evolution of Power-Amplified Predatory Strikes in Trap-Jaw Spiders.

    Science.gov (United States)

    Wood, Hannah M; Parkinson, Dilworth Y; Griswold, Charles E; Gillespie, Rosemary G; Elias, Damian O

    2016-04-25

    Small animals possess intriguing morphological and behavioral traits that allow them to capture prey, including innovative structural mechanisms that produce ballistic movements by amplifying power [1-6]. Power amplification occurs when an organism produces a relatively high power output by releasing slowly stored energy almost instantaneously, resulting in movements that surpass the maximal power output of muscles [7]. For example, trap-jaw, power-amplified mechanisms have been described for several ant genera [5, 8], which have evolved some of the fastest known movements in the animal kingdom [6]. However, power-amplified predatory strikes were not previously known in one of the largest animal classes, the arachnids. Mecysmaucheniidae spiders, which occur only in New Zealand and southern South America, are tiny, cryptic, ground-dwelling spiders that rely on hunting rather than web-building to capture prey [9]. Analysis of high-speed video revealed that power-amplified mechanisms occur in some mecysmaucheniid species, with the fastest species being two orders of magnitude faster than the slowest species. Molecular phylogenetic analysis revealed that power-amplified cheliceral strikes have evolved four times independently within the family. Furthermore, we identified morphological innovations that directly relate to cheliceral function: a highly modified carapace in which the cheliceral muscles are oriented horizontally; modification of a cheliceral sclerite to have muscle attachments; and, in the power-amplified species, a thicker clypeus and clypeal apodemes. These structural innovations may have set the stage for the parallel evolution of ballistic predatory strikes. Copyright © 2016 Elsevier Ltd. All rights reserved.

  9. Mercury Bioaccumulation Response to Recent Hg Pollution Abatement in an Oceanic Predatory Fish, Blue Marlin, Versus the Response in a Coastal Predatory Species, Bluefish, in the Western North Atlantic Ocean

    Science.gov (United States)

    Barber, R. T.; Cross, F. A.

    2015-12-01

    The consumption of marine fish, especially predatory species high in the food chain, is the major route through which people in developed countries are exposed to mercury. Recent work on a coastal species, bluefish (Pomatomus saltatrix), determined that the mercury concentration in fish from the U. S. Mid-Atlantic coast decreased 43% from 1972 to 2011. This mercury decline in a coastal marine fish parallels the mercury decline in many freshwater fish in the U.S. and Canada during the same time period. The result heightens interest in determining whether or not there has been any change in mercury concentration in oceanic predatory fish species, that is, fish that are permanent residents of the open ocean, during the past four decades. To answer this question we compared mercury analyses we made in the 1970s on tournament-caught blue marlin (Makaira nigricans) with those we made from 1998 to 2013. This comparison indicates that from the 1970s to 2013 mercury concentration in blue marlin caught in the western North Atlantic Ocean off the U.S. east coast has declined about 45%, a decline that is remarkably similar to the decline reported in coastal bluefish. These results suggest that a large area of the western North Atlantic Ocean is responding to reductions in emissions of mercury in the U.S. and Canada with reduced mercury bioaccumulation in predatory fish.

  10. Effect of the entomopathogenic fungus Lecanicillium muscariumon the predatory mite Phytoseiulus persimilis as a non-target organism.

    Science.gov (United States)

    Donka, András; Sermann, Helga; Büttner, Carmen

    2008-01-01

    In biological control, different benefit organisms have to combine for an effective management. If entomopathogenic fungi will be integrated, than it has to be considered also the effect on non-target organisms Like beneficial arthropods. Because of the high importance of predatory mite Phytoseiulus persimilis in biological control it was to determine side effects of Leconicillium muscarium on this species. In two standardised biotests in petri dish and on plants (P. vulgaris) individuals were dipped in suspension or set down on leafs after spraying with L. muscarium at different spore density. Results indicate pathogenicity for the predatory mite in principle. But the dimension of infection risk decrease, all the more conditions approach to practical sequence. Under practical conditions on plants and in practical relevant concentration of 10(6) and 10(7) sp./ml no risk is to expect on the plant.

  11. Analysis of Genetic Variation and Phylogeny of the Predatory Bug, Pilophorus typicus, in Japan using Mitochondrial Gene Sequences

    OpenAIRE

    Ito, Katsura; Nishikawa, Hiroshi; Shimada, Takuji; Ogawa, Kohei; Minamiya, Yukio; Tomoda, Masafumi; Nakahira, Kengo; Kodama, Rika; Fukuda, Tatsuya; Arakawa, Ryo

    2011-01-01

    Pilophorus typicus (Distant) (Heteroptera: Miridae) is a predatory bug occurring in East, Southeast, and South Asia. Because the active stages of P. typicus prey on various agricultural pest insects and mites, this species is a candidate insect as an indigenous natural enemy for use in biological control programs. However, the mass releasing of introduced natural enemies into agricultural fields may incur the risk of affecting the genetic integrity of species through hybridization with a loca...

  12. The Potential Application and Risks Associated With the Use of Predatory Bacteria as a Biocontrol Agent Against Wound Infections

    Science.gov (United States)

    2014-09-01

    antibiotics or phage therapy, the selective pressure of predation does not generate genetically stable resistant variants in the host. Since the...bacteria as a live antibiotic , examining the potential risk of predatory bacteria on non-microbial host is essential for the development of a safe...profile, and mice wound size. These experiments use either cyclophosphamide treated mice ( immunocompromised model) or normal mice. Treatment was done

  13. Toxicity of the herbicide glufosinate-ammonium to predatory insects and mites of Tetranychus urticae (Acari: Tetranychidae) under laboratory conditions.

    Science.gov (United States)

    Ahn, Y J; Kim, Y J; Yoo, J K

    2001-02-01

    The toxicities of the herbicide glufosinate-ammonium to three predatory insect and two predatory mite species of Tetranychus urticae Koch were determined in the laboratory by the direct contact application. At a concentration of 540 ppm (a field application rate for weed control in apple orchards), glufosinate-ammonium was almost nontoxic to eggs of Amblyseius womersleyi Schicha, Phytoseiulus persimilis Athias-Henriot, and T. urticae but highly toxic to nymphs and adults of these three mite species, indicating that a common mode of action between predatory and phytophagous mites might be involved. In tests with predatory insects using 540 ppm, glufosinate-ammonium revealed little or no harm to larvae and pupae of Chrysopa pallens Rambur but was slightly harmful to eggs (71.2% mortality), nymphs (65.0% mortality), and adults (57.7% mortality) of Orius strigicollis Poppius. The herbicide showed no direct effect on eggs and adults of Harmonia axyridis (Pallas) but was harmful, slightly harmful, and harmless to first instars (100% mortality), fourth instars (51.1% mortality), and pupae (24.5% mortality), respectively. The larvae and nymphs of predators died within 12 h after treatment, suggesting that the larvicidal and nymphicidal action may be attributable to a direct effect rather than an inhibitory action of chitin synthesis. On the basis of our data, glufosinate-ammonium caused smaller effects on test predators than on T. urticae with the exception of P. persimilis, although the mechanism or cause of selectivity remains unknown. Glufosinate-ammonium merits further study as a key component of integrated pest management.

  14. Disease prevalence and transmission of Microsporidium phytoseiuli infecting the predatory mite, Phytoseiulus persimilis (Acari: Phytoseiidae).

    Science.gov (United States)

    Bjørnson, S; Keddie, B A

    2001-02-01

    Isolated colonies of the predatory mite, Phytoseiulus persimilis, were used to gain information regarding prevalence and transmission of Microsporidium phytoseiuli. Two colonies of P. persimilis were reared on spider mite (Tetranychus urticae)-infested bean plants in isolated cages. Disease prevalence of predators from Colony 1 remained relatively low (between 0 and 15%) over 57 weeks of observation whereas disease prevalence of predators from Colony 2 increased over 3 months (from 12 to 100%). Disease prevalence among predators from Colony 1 had increased to 100% 2 months after weekly sampling had ceased for this colony and periodic sampling confirmed that disease prevalence among individuals of both colonies remained at 100%. Microsporidian spores were not detected in randomly chosen samples of T. urticae prey mites that were removed and examined biweekly during this period. Although numerous microsporidian spores were observed in smear preparations of fecal pellets examined by light microscopy, spores were not observed on leaf surfaces or predator feces when examined by SEM. The latter appeared as intact aggregates composed of numerous dumbbell-shaped crystals and it is unlikely that spores are liberated from intact fecal pellets onto leaf surfaces. Vertical transmission of M. phytoseiuli was 100%; horizontal transmission was low (14.3%) and occurred only when immature P. persimilis were permitted to develop in contact with infected immature and adult predators. The mean number of eggs produced per mated pair was highest when uninfected females were mated with uninfected males (63.2 eggs per mated pair). Although mean egg production decreased when one or both parents were infected, not all differences were significant. Male predatory mites did not contribute to infection of their progeny. Results suggest that routine examination of P. persimilis for microsporidian spores is essential for the management of M. phytoseiuli within P. persimilis colonies. Low disease

  15. Stickleback increase in the Baltic Sea - A thorny issue for coastal predatory fish

    Science.gov (United States)

    Bergström, Ulf; Olsson, Jens; Casini, Michele; Eriksson, Britas Klemens; Fredriksson, Ronny; Wennhage, Håkan; Appelberg, Magnus

    2015-09-01

    In the Baltic Sea, the mesopredator three-spined stickleback (Gasterosteus aculeatus) spends a large part of its life cycle in the open sea, but reproduces in shallow coastal habitats. In coastal waters, it may occur in high abundances, is a potent predator on eggs and larvae of fish, and has been shown to induce trophic cascades with resulting eutrophication symptoms through regulation of invertebrate grazers. Despite its potential significance for the coastal food web, little is known about its life history and population ecology. This paper provides a description of life history traits, migration patterns and spatiotemporal development of the species in the Baltic Sea during the past decades, and tests the hypothesis that stickleback may have a negative impact on populations of coastal predatory fish. Offshore and coastal data during the last 30 years show that stickleback has increased fourfold in the Bothnian Sea, 45-fold in the Central Baltic Sea and sevenfold in the Southern Baltic Sea. The abundances are similar in the two northern basins, and two orders of magnitude lower in the Southern Baltic Sea. The coastward spawning migration of sticklebacks from offshore areas peaks in early May, with most spawners being two years of age at a mean length of 65 mm. The early juvenile stage is spent at the coast, whereafter sticklebacks perform a seaward feeding migration in early autumn at a size of around 35 mm. A negative spatial relation between the abundance of stickleback and early life stages of perch and pike at coastal spawning areas was observed in spatial survey data, indicating strong interactions between the species. A negative temporal relationship was observed also between adult perch and stickleback in coastal fish monitoring programmes supporting the hypothesis that stickleback may have negative population level effects on coastal fish predators. The recent increase in stickleback populations in different basins of the Baltic Sea in combination with

  16. Accelerated proteomic visualization of individual predatory venoms of Conus purpurascens reveals separately evolved predation-evoked venom cabals.

    Science.gov (United States)

    Himaya, S W A; Marí, Frank; Lewis, Richard J

    2018-01-10

    Cone snail venoms have separately evolved for predation and defense. Despite remarkable inter- and intra-species variability, defined sets of synergistic venom peptides (cabals) are considered essential for prey capture by cone snails. To better understand the role of predatory cabals in cone snails, we used a high-throughput proteomic data mining and visualisation approach. Using this approach, the relationship between the predatory venom peptides from nine C. purpurascens was systematically analysed. Surprisingly, potentially synergistic levels of κ-PVIIA and δ-PVIA were only identified in five of nine specimens. In contrast, the remaining four specimens lacked significant levels of these known excitotoxins and instead contained high levels of the muscle nAChR blockers ψ-PIIIE and αA-PIVA. Interestingly, one of nine specimens expressed both cabals, suggesting that these sub-groups might represent inter-breeding sub-species of C. purpurascens. High throughput cluster analysis also revealed these two cabals clustered with distinct groups of venom peptides that are presently uncharacterised. This is the first report showing that the cone snails of the same species can deploy two separate and distinct predatory cabals for prey capture and shows that the cabals deployed by this species can be more complex than presently realized. Our semi-automated proteomic analysis facilitates the deconvolution of complex venoms to identify co-evolved families of peptides and help unravel their evolutionary relationships in complex venoms.

  17. Predatory functional response and prey choice identify predation differences between native/invasive and parasitised/unparasitised crayfish.

    Science.gov (United States)

    Haddaway, Neal R; Wilcox, Ruth H; Heptonstall, Rachael E A; Griffiths, Hannah M; Mortimer, Robert J G; Christmas, Martin; Dunn, Alison M

    2012-01-01

    Invasive predators may change the structure of invaded communities through predation and competition with native species. In Europe, the invasive signal crayfish Pacifastacus leniusculus is excluding the native white clawed crayfish Austropotamobius pallipes. This study compared the predatory functional responses and prey choice of native and invasive crayfish and measured impacts of parasitism on the predatory strength of the native species. Invasive crayfish showed a higher (>10%) prey (Gammarus pulex) intake rate than (size matched) natives, reflecting a shorter (16%) prey handling time. The native crayfish also showed greater selection for crustacean prey over molluscs and bloodworm, whereas the invasive species was a more generalist predator. A. pallipes parasitised by the microsporidian parasite Thelohania contejeani showed a 30% reduction in prey intake. We suggest that this results from parasite-induced muscle damage, and this is supported by a reduced (38%) attack rate and increased (30%) prey handling time. Our results indicate that the per capita (i.e., functional response) difference between the species may contribute to success of the invader and extinction of the native species, as well as decreased biodiversity and biomass in invaded rivers. In addition, the reduced predatory strength of parasitized natives may impair their competitive abilities, facilitating exclusion by the invader.

  18. Cladocerans from gut contents of fishes associated to macrophytes from Taquari River Basin, MS, Brazil Cladóceros do conteúdo estomacal de peixes associados a macrófitas da Bacia do Rio Taquari, MS, Brasil

    Directory of Open Access Journals (Sweden)

    Adriana Maria Güntzel

    2012-03-01

    Full Text Available AIM: The aim of this study was to identify the cladocerans species from the gut contents of fishes sampled in an oxbow lake from Taquari River Basin, MS, with the specific view of investigating the importance of these crustaceans in the fishes diets; METHODS: Sampling was carried out in April and August of 2005 (dry season and January of 2006 (wet season. The fish were captured with a sieve. In the laboratory, individuals were identified and stomachs were removed and weighed. The stomach contents were identified, and a Feeding Index calculated; RESULTS: The items most consumed by fishes were filamentous algae, Cladocera and detritus. The Cladocera were especially important in the August and January samples, and consisted primarily of Chydoridae; cladocerans were most consumed by species of Serrapinnus and by Mesonauta festivus. Fish fed more in April, with decreases occurring in stomach fullness on the other two sampling dates. CONCLUSIONS: Cladocerans associated with macrophytes may be an important food source for small fish individuals in marginal lakes from Taquari River Basin. The relative importance of the Chydoridae in the guts may have been due to the high relative abundance and species richness of this group in the environment. A short discussion on fish feeding habits was included in the text.OBJETIVO: Este estudo teve por objetivo identificar as espécies de cladóceros presentes no conteúdo estomacal de peixes amostrados em uma lagoa marginal da Bacia do Rio Taquari, MS, visando avaliar a importância destes crustáceos na dieta dos peixes; MÉTODOS: A amostragem foi realizada em abril e agosto de 2005 (estação seca e janeiro de 2006 (estação chuvosa. Os peixes foram capturados com um peneirão. Em laboratório, os indivíduos foram identificados até o nível de espécie e os estômagos removidos e pesados. O conteúdo estomacal foi identificado e um Índice Alimentar calculado. RESULTADOS: Os itens mais consumidos pelos peixes

  19. Use of feathers to assess polychlorinated biphenyl and organochlorine pesticide exposure in top predatory bird species of Pakistan

    International Nuclear Information System (INIS)

    Abbasi, Naeem Akhtar; Eulaers, Igor; Jaspers, Veerle L.B.; Chaudhry, Muhammad Jamshed Iqbal; Frantz, Adrien; Ambus, Per Lennart; Covaci, Adrian; Malik, Riffat Naseem

    2016-01-01

    Little is known about the levels of organochlorines (OCs) in predatory bird species from Asia or the factors governing their concentrations. This study is the first report on concentrations of polychlorinated biphenyls (PCBs) and organochlorine pesticides (OCPs) in predatory birds of Pakistan. The concentrations of PCBs and OCPs were investigated using tail feathers of ten different species of predatory birds. In addition, concentration differences among body, tail, primary and secondary feathers were investigated for six individuals of black kite (Milvus migrans). Ranges of concentrations were highest for dichlorodiphenyldichloroethylene (p,p′-DDE: 0.11–2163 ng g − 1 dry wt.) followed by dichlorodiphenyltrichloroethane (p,p′-DDT: 0.36–345 ng g − 1 dry wt.), hexachlorobenzene (HCB: 0.02–34 ng g − 1 dry wt.), ∑ PCBs (0.03–16 ng g − 1 dry wt.) and trans-nonachlor (TN; 0.01–0.13 ng g − 1 dry wt.). CB 118, 153, 138, and 180 along with p,p′-DDE were found as the most prevalent compounds. ∑ PCBs and ∑ DDTs were significantly different among species (both p < 0.01) and omnivorous, scavengers, carnivorous and piscivorous trophic guilds (all p < 0.03). Only ∑ PCBs were significantly differentamong different families of birds (p < 0.01). Values of stable isotopes (δ 13 C and δ 15 N) differed significantly (all p < 0.01) among species, families, trophic guilds as well as terrestrial and aquatic habitat but not between nocturnal and diurnal predators (p = 0.22 for δ 13 C; p = 0.50 for δ 15 N). Concentrations of ∑ PCBs, ∑ DDTs and trans-nonachlor, but not HCB (p = 0.86), were significantly different among different feather types (all p < 0.01). Trophic and taxonomic affiliation as well as dietary carbon sources (δ 13 C) for species were identified as the variables best explaining the observed variation in exposure to the studied compounds. The significance of contributing factors responsible for OC contamination differences in

  20. Use of feathers to assess polychlorinated biphenyl and organochlorine pesticide exposure in top predatory bird species of Pakistan

    Energy Technology Data Exchange (ETDEWEB)

    Abbasi, Naeem Akhtar [Environmental Biology and Ecotoxicology Laboratory, Department of Environmental Sciences, Faculty of Biological Sciences, Quaid-i-Azam University, Islamabad 45320 (Pakistan); Eulaers, Igor [Department of Bioscience, Aarhus University, Frederiksborgvej 399, P.O. Box 358, 4000 Roskilde (Denmark); Jaspers, Veerle L.B., E-mail: veerle.jaspers@ntnu.no [Environmental Toxicology, Department of Biology, Norwegian University of Science and Technology (NTNU), Trondheim (Norway); Chaudhry, Muhammad Jamshed Iqbal [Environmental Biology and Ecotoxicology Laboratory, Department of Environmental Sciences, Faculty of Biological Sciences, Quaid-i-Azam University, Islamabad 45320 (Pakistan); WWF-Pakistan, Ferozpur Road, PO Box 5180, Lahore 54600 (Pakistan); Frantz, Adrien [Sorbonne Universités, UPMC Univ Paris 06, UPEC, Paris 7, CNRS, INRA, IRD, Institut d' Ecologie et des Sciences de l' Environnement de Paris, F-75005 Paris (France); Ambus, Per Lennart [Center for Permafrost, Department of Geosciences and Natural Resource Management, University of Copenhagen, Øster Voldgade 10, 1350 København K (Denmark); Covaci, Adrian [Toxicological Centre, University of Antwerp, Universiteitsplein 1, 2610 Wilrijk (Belgium); Malik, Riffat Naseem, E-mail: r_n_malik2000@yahoo.co.uk [Environmental Biology and Ecotoxicology Laboratory, Department of Environmental Sciences, Faculty of Biological Sciences, Quaid-i-Azam University, Islamabad 45320 (Pakistan)

    2016-11-01

    Little is known about the levels of organochlorines (OCs) in predatory bird species from Asia or the factors governing their concentrations. This study is the first report on concentrations of polychlorinated biphenyls (PCBs) and organochlorine pesticides (OCPs) in predatory birds of Pakistan. The concentrations of PCBs and OCPs were investigated using tail feathers of ten different species of predatory birds. In addition, concentration differences among body, tail, primary and secondary feathers were investigated for six individuals of black kite (Milvus migrans). Ranges of concentrations were highest for dichlorodiphenyldichloroethylene (p,p′-DDE: 0.11–2163 ng g{sup −} {sup 1} dry wt.) followed by dichlorodiphenyltrichloroethane (p,p′-DDT: 0.36–345 ng g{sup −} {sup 1} dry wt.), hexachlorobenzene (HCB: 0.02–34 ng g{sup −} {sup 1} dry wt.), ∑ PCBs (0.03–16 ng g{sup −} {sup 1} dry wt.) and trans-nonachlor (TN; 0.01–0.13 ng g{sup −} {sup 1} dry wt.). CB 118, 153, 138, and 180 along with p,p′-DDE were found as the most prevalent compounds. ∑ PCBs and ∑ DDTs were significantly different among species (both p < 0.01) and omnivorous, scavengers, carnivorous and piscivorous trophic guilds (all p < 0.03). Only ∑ PCBs were significantly differentamong different families of birds (p < 0.01). Values of stable isotopes (δ{sup 13}C and δ{sup 15}N) differed significantly (all p < 0.01) among species, families, trophic guilds as well as terrestrial and aquatic habitat but not between nocturnal and diurnal predators (p = 0.22 for δ{sup 13}C; p = 0.50 for δ{sup 15}N). Concentrations of ∑ PCBs, ∑ DDTs and trans-nonachlor, but not HCB (p = 0.86), were significantly different among different feather types (all p < 0.01). Trophic and taxonomic affiliation as well as dietary carbon sources (δ{sup 13}C) for species were identified as the variables best explaining the observed variation in exposure to the studied compounds. The significance of

  1. Increasing temperature decreases the predatory effect of the intertidal shanny Lipophrys pholis on an amphipod prey

    KAUST Repository

    South, J.

    2017-11-15

    Interactions between Lipophrys pholis and its amphipod prey Echinogammarus marinus were used to investigate the effect of changing water temperatures, comparing current and predicted mean summer temperatures. Contrary to expectations, predator attack rates significantly decreased with increasing temperature. Handling times were significantly longer at 19° C than at 17 and 15° C and the maximum feeding estimate was significantly lower at 19° C than at 17° C. Functional-response type changed from a destabilizing type II to the more stabilizing type III with a temperature increase to 19° C. This suggests that a temperature increase can mediate refuge for prey at low densities. Predatory pressure by teleosts may be dampened by a large increase in temperature (here from 15 to 19° C), but a short-term and smaller temperature increase (to 17° C) may increase destabilizing resource consumption due to high maximum feeding rates; this has implications for the stability of important intertidal ecosystems during warming events.

  2. Traces (ichnospecies Oichnus paraboloides of predatory gastropods on bivalve shells from the Seogwipo Formation, Jejudo, Korea

    Directory of Open Access Journals (Sweden)

    Dal-Yong Kong

    2015-12-01

    Full Text Available Circular to subcircular drill holes were identified on the bivalve shells collected from the Seogwipo Formation, Jejudo, Korea. A great majority of the drill holes (>70% were found on the surfaces of a bivalve species Glycymeris rotunda. They are characterized by a beveled sharp edge and paraboloid in cross section with larger outer borehole diameter (OBD; mean 4.21 mm and smaller inner borehole diameter (mean 2.94 mm. Walls of the drill holes are generally smooth, and walls ornamented with etched relief-like structures were also recognized. A slightly raised central boss observed in an incomplete specimen may indicate a failure of predator’s attack. All drill holes collected are classified as a single ichnospecies Oichnus paraboloides Bromley, 1981. They are interpreted as boring traces produced by predatory gastropods, particularly naticid gastropods. Most O. paraboloides boreholes are observed in the central area of shell surfaces; a few boreholes lie marginally, which may reflect a borehole-site selectivity. No correlation between size of prey (shell height and size of predator (OBD is recognized. It is likely, however, that drilled shells of about 30 mm in height represent optimal prey size for naticid predators that lived in a benthic Seogwipo community.

  3. Population dynamics of interacting predatory mites, Phytoseiulus persimilis and Neoseiulus californicus, held on detached bean leaves.

    Science.gov (United States)

    Walzer, A; Blümel, S; Schausberger, P

    2001-01-01

    The success of combined release of the predatory mites Phytoseiulus persimilis and Neoseiulus californicus in suppression of spider mites may be related to the effects of the interactions between the two predators on their population dynamics. We studied population growth and persistence of the specialist P persimilis and the generalist N. californicus reared singly versus reared in combination after simultaneous and successive predator introductions on detached bean leaf arenas with abundant prey, Tetranychus urticae. and with diminishing prey. When reared singly with abundant prey, either predator population persisted at high densities to the end of the experiment. In every predator combination system with abundant prey and various initial predator:predator ratios N. californicus displaced P persimilis. When held singly with diminishing prey, the population of P. persimilis grew initially faster than the population of N. californicus but both species reached similar population peaks. Irrespective whether reared singly or in combination. N. californicus persisted three to five times longer after prey depletion than did P. persimilis. Regarding the crucial interactions in the predator combination systems, we conclude that intraguild predation was a stronger force than food competition and finally resulted in the displacement of P. persimilis. Previous studies showed that intraguild predation between the specialist P. persimilis and the generalist N. californicus is strongly asymmetric favoring the generalist. We discuss the implications of potential interactions between P. persimilis and N. californicus to biological control of spider mites.

  4. The predatory mite Phytoseiulus persimilis adjusts patch-leaving to own and progeny prey needs.

    Science.gov (United States)

    Vanas, V; Enigl, M; Walzer, A; Schausberger, P

    2006-01-01

    Integration of optimal foraging and optimal oviposition theories suggests that predator females should adjust patch leaving to own and progeny prey needs to maximize current and future reproductive success. We tested this hypothesis in the predatory mite Phytoseiulus persimilis and its patchily distributed prey, the two-spotted spider mite Tetranychus urticae. In three separate experiments we assessed (1) the minimum number of prey needed to complete juvenile development, (2) the minimum number of prey needed to produce an egg, and (3) the ratio between eggs laid and spider mites left when a gravid P. persimilis female leaves a patch. Experiments (1) and (2) were the pre-requirements to assess the fitness costs associated with staying or leaving a prey patch. Immature P. persimilis needed at least 7 and on average 14+/-3.6 (SD) T. urticae eggs to reach adulthood. Gravid females needed at least 5 and on average 8.5+/-3.1 (SD) T. urticae eggs to produce an egg. Most females left the initial patch before spider mite extinction, leaving prey for progeny to develop to adulthood. Females placed in a low density patch left 5.6+/-6.1 (SD) eggs per egg laid, whereas those placed in a high density patch left 15.8+/-13.7 (SD) eggs per egg laid. The three experiments in concert suggest that gravid P. persimilis females are able to balance the trade off between optimal foraging and optimal oviposition and adjust patch-leaving to own and progeny prey needs.

  5. Integration of multiple cues allows threat-sensitive anti-intraguild predator responses in predatory mites

    Science.gov (United States)

    Walzer, Andreas; Schausberger, Peter

    2013-01-01

    Intraguild (IG) prey is commonly confronted with multiple IG predator species. However, the IG predation (IGP) risk for prey is not only dependent on the predator species, but also on inherent (intraspecific) characteristics of a given IG predator such as its life-stage, sex or gravidity and the associated prey needs. Thus, IG prey should have evolved the ability to integrate multiple IG predator cues, which should allow both inter- and intraspecific threat-sensitive anti-predator responses. Using a guild of plant-inhabiting predatory mites sharing spider mites as prey, we evaluated the effects of single and combined cues (eggs and/or chemical traces left by a predator female on the substrate) of the low risk IG predator Neoseiulus californicus and the high risk IG predator Amblyseius andersoni on time, distance and path shape parameters of the larval IG prey Phytoseiulus persimilis. IG prey discriminated between traces of the low and high risk IG predator, with and without additional presence of their eggs, indicating interspecific threat-sensitivity. The behavioural changes were manifest in distance moved, activity and path shape of IG prey. The cue combination of traces and eggs of the IG predators conveyed other information than each cue alone, allowing intraspecific threat-sensitive responses by IG prey apparent in changed velocities and distances moved. We argue that graded responses to single and combined IG predator cues are adaptive due to minimization of acceptance errors in IG prey decision making. PMID:23750040

  6. Intraguild interactions between the predatory mites Neoseiulus californicus and Phytoseiulus persimilis.

    Science.gov (United States)

    Cakmak, Ibrahim; Janssen, Arne; Sabelis, Maurice W

    2006-01-01

    Species at the same trophic level may interact through competition for food, but can also interact through intraguild predation. Intraguild predation is widespread at the second and third trophic level and the effects may cascade down to the plant level. The effects of intraguild predation can be modified by antipredator behaviour in the intraguild prey. We studied intraguild predation and antipredator behaviour in two species of predatory mite, Neoseiulus californicus and Phytoseiulus persimilis, which are both used for control of the two-spotted spider mite in greenhouse and outdoor crops. Using a Y-tube olfactometer, we assessed in particular whether each of the two predators avoids odours emanating from prey patches occupied by the heterospecific predator. Furthermore, we measured the occurrence and rate of intraguild predation of different developmental stages of P. persimilis and N. californicus on bean leaves in absence or in presence of the shared prey. Neither of the two predator species avoided prey patches with the heterospecific competitor, both when inexperienced with the other predator and when experienced with prey patches occupied by the heterospecific predator. Intraguild experiments showed that N. californicus is a potential intraguild predator of P. persimilis. However, P. persimilis did not suffer much from intraguild predation as long as the shared prey was present. This is probably because N. californicus prefers to feed on two-spotted spider mites rather than on its intraguild prey.

  7. Plant architecture and prey distribution influence foraging behavior of the predatory mite Phytoseiulus persimilis (Acari: Phytoseiidae).

    Science.gov (United States)

    Gontijo, Lessando M; Nechols, James R; Margolies, David C; Cloyd, Raymond A

    2012-01-01

    The arrangement, number, and size of plant parts may influence predator foraging behavior, either directly, by altering the rate or pattern of predator movement, or, indirectly, by affecting the distribution and abundance of prey. We report on the effects of both plant architecture and prey distribution on foraging by the predatory mite, Phytoseiulus persimilis Athias-Henriot (Acari: Phytoseiidae), on cucumber (Cucumis sativus L.). Plants differed in leaf number (2- or 6-leafed), and there were associated differences in leaf size, plant height, and relative proportions of plant parts; but all had the same total surface area. The prey, the twospotted spider mite Tetranychus urticae Koch (Acari: Tetranychidae), were distributed either on the basal leaf or on all leaves. The effect of plant architecture on predator foraging behavior varied depending on prey distribution. The dimensions of individual plant parts affected time allocated to moving and feeding, but they did not appear to influence the frequency with which predators moved among different plant parts. Overall, P. persimilis moved less, and fed upon prey longer, on 6-leafed plants with prey on all leaves than on plants representing other treatment combinations. Our findings suggest that both plant architecture and pattern of prey distribution should be considered, along with other factors such as herbivore-induced plant volatiles, in augmentative biological control programs.

  8. Acaricomes phytoseiuli gen. nov., sp. nov., isolated from the predatory mite Phytoseiulus persimilis.

    Science.gov (United States)

    Pukall, Rüdiger; Schumann, Peter; Schütte, Conny; Gols, Rieta; Dicke, Marcel

    2006-02-01

    A Gram-positive, rod-shaped, non-spore-forming bacterium, strain CSCT, was isolated from diseased, surface-sterilized specimens of the predatory mite Phytoseiulus persimilis Athias-Henriot and subjected to polyphasic taxonomic analysis. Comparative analysis of the 16S rRNA gene sequence revealed that the strain was a new member of the family Micrococcaceae. Nearest phylogenetic neighbours were determined as Renibacterium salmoninarum (94.0%), Arthrobacter globiformis (94.8%) and Arthrobacter russicus (94.6%). Although the predominant fatty acids (anteiso C15:0), cell-wall sugars (galactose, glucose) and polar lipids (diphosphatidylglycerol, phosphatidylglycerol, phosphatidylinositol) are in accordance with those of members of the genus Arthrobacter, strain CSCT can be distinguished from members of the genus Arthrobacter by biochemical tests, the absence of a rod-coccus life cycle and the occurrence of the partially saturated menaquinone MK-10(H2) as the predominant menaquinone. The DNA G+C content is 57.7 mol%. On the basis of morphological, chemotaxonomic and phylogenetic differences from other species of the Micrococcaceae, a novel genus and species are proposed, Acaricomes phytoseiuli gen. nov., sp. nov. The type strain is CSCT (=DSM 14247T=CCUG 49701T).

  9. Increasing temperature decreases the predatory effect of the intertidal shanny Lipophrys pholis on an amphipod prey

    KAUST Repository

    South, J.; Welsh, D.; Anton, A.; Sigwart, J. D.; Dick, J. T. A.

    2017-01-01

    Interactions between Lipophrys pholis and its amphipod prey Echinogammarus marinus were used to investigate the effect of changing water temperatures, comparing current and predicted mean summer temperatures. Contrary to expectations, predator attack rates significantly decreased with increasing temperature. Handling times were significantly longer at 19° C than at 17 and 15° C and the maximum feeding estimate was significantly lower at 19° C than at 17° C. Functional-response type changed from a destabilizing type II to the more stabilizing type III with a temperature increase to 19° C. This suggests that a temperature increase can mediate refuge for prey at low densities. Predatory pressure by teleosts may be dampened by a large increase in temperature (here from 15 to 19° C), but a short-term and smaller temperature increase (to 17° C) may increase destabilizing resource consumption due to high maximum feeding rates; this has implications for the stability of important intertidal ecosystems during warming events.

  10. Effects of Beauveria bassiana on predation and behavior of the predatory mite Phytoseiulus persimilis.

    Science.gov (United States)

    Wu, Shengyong; Xing, Zhenlong; Sun, Weinan; Xu, Xuenong; Meng, Ruixia; Lei, Zhongren

    2018-03-01

    Determination of intraguild interactions between entomopathogens and predators is important when attempting to use a combination of these two natural enemy groups for biological control of their shared arthropod pest species. This study assessed the effects of Beauveria bassiana on the predation and associated behavior of the predatory mite, Phytoseiulus persimilis, against Tetranychus urticae. The functional response tests showed that P. persimilis exhibited a Holling type II response on the spider mite, Tetranychus urticae, when treated with either a B. bassiana or Tween-80 suspension. There were no significant differences between the treatments in the number of T. urticae consumed. The laboratory choice test indicated that P. persimilis displayed a significant avoidance response to B. bassiana on bean leaves immediately following spray application. They also spent significantly longer time in self-grooming behavior on leaf disks sprayed with fungal conidia than on discs treated with Tween-80. There were no significant differences in the predation rates on T. urticae eggs between the different treatments. The potted plant investigations indicated that P. persimilis showed significant aversion behavior to the initial fungal spray, but gradually dispersed over the entire bean plants. Observations using scanning electron microscopy revealed that fungal conidia were attached to the body of P. persimilis after mounting the leaf disk treated with B. bassiana, which would account for its varied behavioral responses. Our study suggests that fungal spray did not affect the predation capability of P. persimilis and poses a negligible risk to their behavior. Copyright © 2018 Elsevier Inc. All rights reserved.

  11. Population-level effects of abamectin, azadirachtin and fenpyroximate on the predatory mite Neoseiulus baraki.

    Science.gov (United States)

    Lima, Debora B; Melo, José W S; Gondim, Manoel G C; Guedes, Raul N C; Oliveira, José E M

    2016-10-01

    The coconut production system, in which the coconut mite Aceria guerreronis is considered a key pest, provides an interesting model for integration of biological and chemical control. In Brazil, the most promising biological control agent for the coconut mite is the phytoseiid predator Neoseiulus baraki. However, acaricides are widely used to control the coconut mite, although they frequently produce unsatisfactory results. In this study, we evaluated the simultaneous direct effect of dry residue contact and contaminated prey ingestion of the main acaricides used on coconut palms (i.e., abamectin, azadirachtin and fenpyroximate) on life-history traits of N. baraki and their offspring. These acaricides are registered, recommended and widely used against A. guerreronis in Brazil, and they were tested at their label rates. The offspring of the exposed predators was also evaluated by estimating the instantaneous rate of population increase (r i ). Abamectin compromised female performance, whereas fenpyroximate did not affect the exposed females (F0). Nonetheless, fenpyroximate strongly compromised the offspring (F1) net reproductive rate (R0), intrinsic rate of population growth (r i ), and doubling time (DT). In contrast, fenpyroximate did not have such effects on the 2nd generation (F2) of predators with acaricide-exposed grandparents. Azadirachtin did not affect the predators, suggesting that this acaricide can be used in association with biological control by this predatory species. In contrast, the use of abamectin and fenpyroximate is likely to lead to adverse consequences in the biological control of A. guerreronis using N. baraki.

  12. The use of artificial crabs for testing predatory behavior and health in the octopus.

    Science.gov (United States)

    Amodio, Piero; Andrews, Paul; Salemme, Marinella; Ponte, Giovanna; Fiorito, Graziano

    2014-01-01

    The willingness of the cephalopod mollusc Octopus vulgaris to attack a live crab is traditionally used as a method to assess the overall health and welfare of octopuses in the laboratory. This method requires placing a crab in the home tank of an animal, measuring the time (latency) taken for the octopus to initiate an attack and withdrawing the crab immediately prior to capture. The same crab is commonly used to assess multiple octopuses as part of daily welfare assessment. Growing concern for the welfare of crustaceans and a review of all laboratory practices for the care and welfare of cephalopods following the inclusion of this taxon in 2010/63/EU prompted a study of the utility of an artificial crab to replace a live crab in the assessment of octopus health. On consecutive days O. vulgaris (N=21) were presented with a live, a dead or an artificial crab, and the latency to attack measured. Despite differences in the predatory performance towards the three different crab alternatives, octopuses readily attacked the artificial (and the dead) crab, showing that they can generalize and respond appropriately towards artificial prey. Researchers should consider using an artificial crab to replace the use of a live crab as part of the routine health assessment of O. vulgaris.

  13. Aphid secondary symbionts do not affect prey attractiveness to two species of predatory lady beetles.

    Directory of Open Access Journals (Sweden)

    Jennifer L Kovacs

    Full Text Available Heritable symbionts have been found to mediate interactions between host species and their natural enemies in a variety of organisms. Aphids, their facultative symbionts, and their potential fitness effects have been particularly well-studied. For example, the aphid facultative symbiont Regiella can protect its host from infection from a fungal pathogen, and aphids with Hamiltonella are less likely to be parasitized by parasitic wasps. Recent work has also found there to be negative fitness effects for the larvae of two species of aphidophagous lady beetles that consumed aphids with facultative symbionts. In both species, larvae that consumed aphids with secondary symbionts were significantly less likely to survive to adulthood. In this study we tested whether adult Harmonia axyridis and Hippodamia convergens lady beetles avoided aphids with symbionts in a series of choice experiments. Adults of both lady beetle species were as likely to choose aphids with symbionts as those without, despite the potential negative fitness effects associated with consuming aphids with facultative symbionts. This may suggest that under natural conditions aphid secondary symbionts are not a significant source of selection for predatory lady beetles.

  14. Combined Venom Gland Transcriptomic and Venom Peptidomic Analysis of the Predatory Ant Odontomachus monticola

    Directory of Open Access Journals (Sweden)

    Kohei Kazuma

    2017-10-01

    Full Text Available Ants (hymenoptera: Formicidae have adapted to many different environments and have become some of the most prolific and successful insects. To date, 13,258 ant species have been reported. They have been classified into 333 genera and 17 subfamilies. Except for a few Formicinae, Dolichoderinae, and members of other subfamilies, most ant species have a sting with venom. The venoms are composed of formic acid, alkaloids, hydrocarbons, amines, peptides, and proteins. Unlike the venoms of other animals such as snakes and spiders, ant venoms have seldom been analyzed comprehensively, and their compositions are not yet completely known. In this study, we used both transcriptomic and peptidomic analyses to study the composition of the venom produced by the predatory ant species Odontomachus monticola. The transcriptome analysis yielded 49,639 contigs, of which 92 encoded toxin-like peptides and proteins with 18,106,338 mapped reads. We identified six pilosulin-like peptides by transcriptomic analysis in the venom gland. Further, we found intact pilosulin-like peptide 1 and truncated pilosulin-like peptides 2 and 3 by peptidomic analysis in the venom. Our findings related to ant venom peptides and proteins may lead the way towards development and application of novel pharmaceutical and biopesticidal resources.

  15. Canalization of body size matters for lifetime reproductive success of male predatory mites (Acari: Phytoseiidae).

    Science.gov (United States)

    Walzer, Andreas; Schausberger, Peter

    2014-04-01

    The adaptive canalization hypothesis predicts that highly fitness-relevant traits are canalized via past selection, resulting in low phenotypic plasticity and high robustness to environmental stress. Accordingly, we hypothesized that the level of phenotypic plasticity of male body size of the predatory mites Phytoseiulus persimilis (low plasticity) and Neoseiulus californicus (high plasticity) reflects the effects of body size variation on fitness, especially male lifetime reproductive success (LRS). We first generated small and standard-sized males of P. persimilis and N. californicus by rearing them to adulthood under limited and ample prey supply, respectively. Then, adult small and standard-sized males were provided with surplus virgin females throughout life to assess their mating and reproductive traits. Small male body size did not affect male longevity or the number of fertilized females but reduced male LRS of P. persimilis but not N. californicus . Proximately, the lower LRS of small than standard-sized P. persimilis males correlated with shorter mating durations, probably decreasing the amount of transferred sperm. Ultimately, we suggest that male body size is more strongly canalized in P. persimilis than N. californicus because deviation from standard body size has larger detrimental fitness effects in P. persimilis than N. californicus .

  16. Differential effects of ethanol on feline rage and predatory attack behavior: an underlying neural mechanism.

    Science.gov (United States)

    Schubert, K; Shaikh, M B; Han, Y; Poherecky, L; Siegel, A

    1996-08-01

    Previous studies have shown that, at certain dose levels, ethanol can exert a powerful, facilitatory effect on aggressive behavior in both animals and humans. In the cat, however, it was discovered that ethanol differentially alters two forms of aggression that are common to this species. Defensive rage behavior is significantly enhanced, whereas predatory attack behavior is suppressed by ethanol administration. One possible mechanism governing alcohol's potentiation of defensive rage behavior is that it acts on the descending pathway from the medial hypothalamus to the midbrain periaqueductal gray (PAG)-an essential pathway for the expression of defensive rage behavior that uses excitatory amino acids as a neurotransmitter. This hypothesis is supported by the finding that the excitatory effects of alcohol on defensive rage behavior are blocked by administration of the N-methyl-D-aspartate antagonist alpha-2-amino-7-phosphoheptanoic acid (AP-7) when microinjected into the periaqueductal gray, a primary neuronal target of descending fibers from the medial hypothalamus that mediate the expression of defensive rage behavior. Thus, the present study establishes for the first time a specific component of the neural circuit for defensive rage behavior over which the potentiating effects of ethanol are mediated.

  17. Physiological selectivity and activity reduction of insecticides by rainfall to predatory wasps of Tuta absoluta.

    Science.gov (United States)

    Barros, Emerson C; Bacci, Leandro; Picanco, Marcelo C; Martins, Júlio C; Rosado, Jander F; Silva, Gerson A

    2015-01-01

    In this study, we carried out three bioassays with nine used insecticides in tomato crops to identify their efficiency against tomato leaf miner Tuta absoluta, the physiological selectivity and the activity reduction of insecticides by three rain regimes to predatory wasps Protonectarina sylveirae and Polybia scutellaris. We assessed the mortality caused by the recommended doses of abamectin, beta-cyfluthrin, cartap, chlorfenapyr, etofenprox, methamidophos, permethrin, phenthoate and spinosad to T. absoluta and wasps at the moment of application. In addition, we evaluated the wasp mortality due to the insecticides for 30 days on plants that did not receive rain and on plants that received 4 or 125 mm of rain. Spinosad, cartap, chlorfenapyr, phenthoate, abamectin and methamidophos caused mortality higher than 90% to T. absoluta, whereas the pyrethroids beta-cyfluthrin, etofenprox and permethrin caused mortality between 8.5% and 46.25%. At the moment of application, all the insecticides were highly toxic to the wasps, causing mortality higher than 80%. In the absence of rain, all the insecticides continued to cause high mortality to the wasps for 30 days after the application. The toxicity of spinosad and methamidophos on both wasp species; beta-cyfluthrin on P. sylveirae and chlorfenapyr and abamectin on P. scutellaris, decreased when the plants received 4 mm of rain. In contrast, the other insecticides only showed reduced toxicity on the wasps when the plants received 125 mm of rain.

  18. Simulating ocean acidification and CO2 leakages from carbon capture and storage to assess the effects of pH reduction on cladoceran Moina mongolica Daday and its progeny.

    Science.gov (United States)

    Wang, Zaosheng; Wang, Youshao; Yan, Changzhou

    2016-07-01

    In order to evaluate the effects of pH reduction in seawater as a result of increasing levels of atmospheric CO2, laboratory-scale experiments simulating the scenarios of ocean acidification (OA) and CO2 leakages of carbon capture and storage (CCS) were performed using the model organism Moina mongolica Daday. The LpH50s calculated in cladoceran toxicity tests showed that M. mongolica exhibited intermediate sensitivity to OA, which varied among species and with ontogeny, when compared with different phyla or classes of marine biota. Survival, reproduction and fecundity of parthenogenetic females were evaluated after 21-day exposures. Results showed that increased acidity significantly reduced the rate of reproduction of M. mongolica resulting in a decreased intrinsic rate of natural increase (rm) across the gradients of pH reduction. The analysis of macromolecule contents in neonates suggested that nutritional status in progeny from all broods were significantly reduced as seawater pH decreased, with increasing magnitude in latter broods, except the contents of protein from two former broods and lipids from the first brood. Our findings clearly showed that for this ecologically and economically important fish species, the negative effects of pH reduction on both "quantity" and "quality" of progeny may have far-reaching implications, providing direct evidence that OA could influence the energetic transfer of marine food web and ecosystem functions in acidified oceans in the future. Copyright © 2016 Elsevier Ltd. All rights reserved.

  19. Hypoxia, blackwater and fish kills: experimental lethal oxygen thresholds in juvenile predatory lowland river fishes.

    Directory of Open Access Journals (Sweden)

    Kade Small

    Full Text Available Hypoxia represents a growing threat to biodiversity in freshwater ecosystems. Here, aquatic surface respiration (ASR and oxygen thresholds required for survival in freshwater and simulated blackwater are evaluated for four lowland river fishes native to the Murray-Darling Basin (MDB, Australia. Juvenile stages of predatory species including golden perch Macquaria ambigua, silver perch Bidyanus bidyanus, Murray cod Maccullochella peelii, and eel-tailed catfish Tandanus tandanus were exposed to experimental conditions of nitrogen-induced hypoxia in freshwater and hypoxic blackwater simulations using dried river red gum Eucalyptus camaldulensis leaf litter. Australia's largest freshwater fish, M. peelii, was the most sensitive to hypoxia but given that we evaluated tolerances of juveniles (0.99 ± 0.04 g; mean mass ±SE, the low tolerance of this species could not be attributed to its large maximum attainable body mass (>100,000 g. Concentrations of dissolved oxygen causing 50% mortality (LC50 in freshwater ranged from 0.25 ± 0.06 mg l(-1 in T. tandanus to 1.58 ± 0.01 mg l(-1 in M. peelii over 48 h at 25-26 °C. Logistic models predicted that first mortalities may start at oxygen concentrations ranging from 2.4 mg l(-1 to 3.1 mg l(-1 in T. tandanus and M. peelii respectively within blackwater simulations. Aquatic surface respiration preceded mortality and this behaviour is documented here for the first time in juveniles of all four species. Despite the natural occurrence of hypoxia and blackwater events in lowland rivers of the MDB, juvenile stages of these large-bodied predators are vulnerable to mortality induced by low oxygen concentration and water chemistry changes associated with the decomposition of organic material. Given the extent of natural flow regime alteration and climate change predictions of rising temperatures and more severe drought and flooding, acute episodes of hypoxia may represent an underappreciated risk to riverine fish

  20. Early social isolation impairs development, mate choice and grouping behaviour of predatory mites.

    Science.gov (United States)

    Schausberger, Peter; Gratzer, Marian; Strodl, Markus A

    2017-05-01

    The social environment early in life is a key determinant of developmental, physiological and behavioural trajectories across vertebrate and invertebrate animals. One crucial variable is the presence/absence of conspecifics. For animals usually reared in groups, social isolation after birth or hatching can be a highly stressful circumstance, with potentially long-lasting consequences. Here, we assessed the effects of social deprivation (isolation) early in life, that is, absence of conspecifics, versus social enrichment, that is, presence of conspecifics, on developmental time, body size at maturity, mating behaviour and group-living in the plant-inhabiting predatory mite Phytoseiulus persimilis . Socially deprived protonymphs developed more slowly and were less socially competent in grouping behaviour than socially enriched protonymphs. Compromised social competence in grouping behaviour was evident in decreased activity, fewer mutual encounters and larger interindividual distances, all of which may entail severe fitness costs. In female choice/male competition, socially deprived males mated earlier than socially enriched males; in male choice/female competition, socially deprived females were more likely to mate than socially enriched females. In neither mate choice situation did mating duration or body size at maturity differ between socially deprived and enriched mating opponents. Social isolation-induced shifts in mating behaviour may be interpreted as increased attractiveness or competitiveness or, more likely, as hastiness and reduced ability to assess mate quality. Overall, many of the social isolation-induced behavioural changes in P. persimilis are analogous to those observed in other animals such as cockroaches, fruit flies, fishes or rodents. We argue that, due to their profound and persistent effects, early social deprivation or enrichment may be important determinants in shaping animal personalities.

  1. Integration of multiple intraguild predator cues for oviposition decisions by a predatory mite

    Science.gov (United States)

    Walzer, Andreas; Schausberger, Peter

    2012-01-01

    In mutual intraguild predation (IGP), the role of individual guild members is strongly context dependent and, during ontogeny, can shift from an intraguild (IG) prey to a food competitor or to an IG predator. Consequently, recognition of an offspring's predator is more complex for IG than classic prey females. Thus, IG prey females should be able to modulate their oviposition decisions by integrating multiple IG predator cues and by experience. Using a guild of plant-inhabiting predatory mites sharing the spider mite Tetranychus urticae as prey and passing through ontogenetic role shifts in mutual IGP, we assessed the effects of single and combined direct cues of the IG predator Amblyseius andersoni (eggs and traces left by a female on the substrate) on prey patch selection and oviposition behaviour of naïve and IG predator-experienced IG prey females of Phytoseiulus persimilis. The IG prey females preferentially resided in patches without predator cues when the alternative patch contained traces of predator females or the cue combination. Preferential egg placement in patches without predator cues was only apparent in the choice situation with the cue combination. Experience increased the responsiveness of females exposed to the IG predator cue combination, indicated by immediate selection of the prey patch without predator cues and almost perfect oviposition avoidance in patches with the cue combination. We argue that the evolution of the ability of IG prey females to evaluate offspring's IGP risk accurately is driven by the irreversibility of oviposition and the functionally complex relationships between predator guild members. PMID:23264692

  2. Social familiarity modulates group living and foraging behaviour of juvenile predatory mites

    Science.gov (United States)

    Strodl, Markus A.; Schausberger, Peter

    2012-04-01

    Environmental stressors during early life may have persistent consequences for phenotypic development and fitness. In group-living species, an important stressor during juvenile development is the presence and familiarity status of conspecific individuals. To alleviate intraspecific conflicts during juvenile development, many animals evolved the ability to discriminate familiar and unfamiliar individuals based on prior association and use this ability to preferentially associate with familiar individuals. Assuming that familiar neighbours require less attention than unfamiliar ones, as predicted by limited attention theory, assorting with familiar individuals should increase the efficiency in other tasks. We assessed the influence of social familiarity on within-group association behaviour, development and foraging of juvenile life stages of the group-living, plant-inhabiting predatory mite Phytoseiulus persimilis. The observed groups consisted either of mixed-age familiar and unfamiliar juvenile mites or of age-synchronized familiar or unfamiliar juvenile mites or of pairs of familiar or unfamiliar larvae. Overall, familiar mites preferentially grouped together and foraged more efficiently, i.e. needed less prey at similar developmental speed and body size at maturity, than unfamiliar mites. Preferential association of familiar mites was also apparent in the inter-exuviae distances. Social familiarity was established by imprinting in the larval stage, was not cancelled or overridden by later conspecific contacts and persisted into adulthood. Life stage had an effect on grouping with larvae being closer together than nymphal stages. Ultimately, optimized foraging during the developmental phase may relax within-group competition, enhance current and future food supply needed for optimal development and optimize patch exploitation and leaving under limited food.

  3. Innate responses of the predatory mite Phytoseiulus persimilis to a herbivore-induced plant volatile.

    Science.gov (United States)

    Sznajder, B; Sabelis, M W; Egas, M

    2011-06-01

    The responses of the predatory mite P. persimilis to herbivore-induced plant volatiles are at least partly genetically determined. Thus, there is potential for the evolution of this behaviour by natural selection. We tested whether distinct predator genotypes with contrasting responses to a specific herbivore-induced plant volatile, i.e. methyl salicylate (MeSa), could be found in a base population collected in the field (Sicily). To this end, we imposed purifying selection on individuals within iso-female lines of P. persimilis such that the lines were propagated only via the individual that showed either a preference or avoidance of MeSa. The responses of the lines were characterized as the mean proportion of individuals choosing MeSa when given a choice between MeSa and clean air. Significant variation in predator responses was detected among iso-female lines, thus confirming the presence of a genetic component for this behaviour. Nevertheless, we did not find a significant difference in the response to MeSa between the lines that were selected to avoid MeSa and the lines selected to prefer MeSa. Instead, in the course of selection the lines selected to avoid MeSa shifted their mean response towards a preference for MeSa. An inverse, albeit weaker, shift was detected for the lines selected to prefer MeSa. We discuss the factors that may have caused the apparent lack of a response to selection within iso-female line in this study and propose experimental approaches that address them.

  4. Interdependent effects of male and female body size plasticity on mating behaviour of predatory mites.

    Science.gov (United States)

    Walzer, Andreas; Schausberger, Peter

    2015-02-01

    The adaptive canalization hypothesis predicts that traits with low phenotypic plasticity are more fitness relevant, because they have been canalized via strong past selection, than traits with high phenotypic plasticity. Based on differing male body size plasticities of the predatory mites Phytoseiulus persimilis (low plasticity) and Neoseiulus californicus (high plasticity), we accordingly hypothesized that small male body size entails higher costs in female choice and male-male competition in P. persimilis than N. californicus . Males of both species are highly polygynous but females differ in the level of polyandry (low level in P. persimilis ; medium level in N. californicus ). We videotaped the mating interactions in triplets of either P. persimilis or N. californicus , consisting of a virgin female (small or standard-sized) and a small and a standard-sized male. Mating by both small and standard-sized P. persimilis females was biased towards standard-sized males, resulting from the interplay between female preference for standard-sized males and the inferiority of small males in male-male competition. In contrast, mating by N. californicus females was equally balanced between small and standard-sized males. Small N. californicus males were more aggressive ('Napoleon complex') in male-male competition, reducing the likelihood of encounter between the standard-sized male and the female, and thus counterbalancing female preference for standard-sized males. Our results support the hypothesis that male body size is more important to fitness in the low-level polyandrous P. persimilis than in the medium-level polyandrous N. californicus and provide a key example of the implications of sexually selected body size plasticity on mating behaviour.

  5. Maternal manipulation of hatching asynchrony limits sibling cannibalism in the predatory mite Phytoseiulus persimilis.

    Science.gov (United States)

    Schausberger, P; Hoffmann, D

    2008-11-01

    1. Sibling cannibalism is a common phenomenon in the animal kingdom but entails a high risk of direct and inclusive fitness loss for the mother and her offspring. Therefore, mechanisms limiting sibling cannibalism are expected to be selected for. One way of maternal manipulation of sibling cannibalism is to influence hatching asynchrony between nearby laid eggs. This has rarely been tested experimentally. 2. We examined the ability of ovipositing females of the cannibalistic predatory mite Phytoseiulus persimilis to influence the occurrence of sibling cannibalism among offspring by manipulating hatching asynchrony of nearby laid eggs. 3. In the first experiment, we assessed the occurrence of sibling cannibalism in relation to the hatching interval (24 h and 48 h) between nearby laid eggs. In the second experiment, we tested whether ovipositing females discriminate sites containing young (24-h old) and old (48-h old) eggs, fresh and old traces (metabolic waste products and possibly pheromones) left by the same female (24 h and 48 h ago), or young eggs plus fresh female traces and old eggs plus old female traces. Both experiments were conducted with and without prey. 4. Without prey, siblings were more likely to cannibalize each other if the hatching interval between nearby laid eggs was short (24 h). Cannibalism occurred less often when senior siblings (protonymphs) experienced a delay in the opportunity to cannibalize junior siblings (larvae). 5. Independent of prey availability, females preferentially added new eggs to sites containing old eggs plus old female traces but did neither distinguish between young and old eggs presented without own traces nor between fresh and old traces presented without eggs. 6. We discuss cue perception and use by P. persimilis females and contrast the outcome of our experiments and theoretical predictions of sibling cannibalism. We conclude that P. persimilis mothers increase hatching asynchrony of nearby laid eggs to prevent

  6. Balancing in- and out-breeding by the predatory mite Phytoseiulus persimilis.

    Science.gov (United States)

    Atalay, Demet; Schausberger, Peter

    2018-02-01

    In- and out-breeding depressions are commonly observed phenomena in sexually reproducing organisms with a patchy distribution pattern, and spatial segmentation and/or isolation of groups. At the genetic level, inbreeding depression is due to increased homozygosity, whereas outbreeding depression is due to inferior genetic compatibility of mates. Optimal outbreeding theory suggests that intermediate levels of mate relatedness should provide for the highest fitness gains. Here, we assessed the fitness consequences of genetic relatedness between mates in plant-inhabiting predatory mites Phytoseiulus persimilis, which are obligatory sexually reproducing but haplo-diploid. Both females and males arise from fertilized eggs but males lose the paternal chromosome set during embryogenesis, dubbed pseudo-arrhenotoky. Phytoseiulus persimilis are highly efficacious in reducing crop-damaging spider mite populations and widely used in biological control. Using iso-female lines of two populations, from Sicily and Greece, we assessed the fecundity of females, and sex ratio of their offspring, that mated with either a sibling, a male from the same population or a male from the other population. Additionally, we recorded mating latency and duration. Females mating with a male from the same population produced more eggs, with a lower female bias, over a longer time than females mating with a sibling or with a male from the other population. Mating latency was unaffected by mate relatedness; mating duration was disproportionally long in sibling couples, likely indicating female reluctance to mate and sub-optimal spermatophore transfer. Our study provides a rare example of in- and out-breeding depression in a haplo-diploid arthropod, supporting the optimal outbreeding theory.

  7. Nocturnal herbivore-induced plant volatiles attract the generalist predatory earwig Doru luteipes Scudder

    Science.gov (United States)

    Naranjo-Guevara, Natalia; Peñaflor, Maria Fernanda G. V.; Cabezas-Guerrero, Milton F.; Bento, José Maurício S.

    2017-10-01

    Numerous studies have demonstrated that entomophagous arthropods use herbivore-induced plant volatile (HIPV) blends to search for their prey or host. However, no study has yet focused on the response of nocturnal predators to volatile blends emitted by prey damaged plants. We investigated the olfactory behavioral responses of the night-active generalist predatory earwig Doru luteipes Scudder (Dermaptera: Forficulidae) to diurnal and nocturnal volatile blends emitted by maize plants ( Zea mays) attacked by either a stem borer ( Diatraea saccharalis) or a leaf-chewing caterpillar ( Spodoptera frugiperda), both suitable lepidopteran prey. Additionally, we examined whether the earwig preferred odors emitted from short- or long-term damaged maize. We first determined the earwig diel foraging rhythm and confirmed that D. luteipes is a nocturnal predator. Olfactometer assays showed that during the day, although the earwigs were walking actively, they did not discriminate the volatiles of undamaged maize plants from those of herbivore damaged maize plants. In contrast, at night, earwigs preferred volatiles emitted by maize plants attacked by D. saccharalis or S. frugiperda over undamaged plants and short- over long-term damaged maize. Our GC-MS analysis revealed that short-term damaged nocturnal plant volatile blends were comprised mainly of fatty acid derivatives (i.e., green leaf volatiles), while the long-term damaged plant volatile blend contained mostly terpenoids. We also observed distinct volatile blend composition emitted by maize damaged by the different caterpillars. Our results showed that D. luteipes innately uses nocturnal herbivore-induced plant volatiles to search for prey. Moreover, the attraction of the earwig to short-term damaged plants is likely mediated by fatty acid derivatives.

  8. Discovery of Bioactive Metabolites in Biofuel Microalgae That Offer Protection against Predatory Bacteria

    Directory of Open Access Journals (Sweden)

    Christopher eBagwell

    2016-04-01

    systems while ensuring the protection of biomass from predatory losses.

  9. Residency and movement patterns of an apex predatory shark (Galeocerdo cuvier at the Galapagos Marine Reserve.

    Directory of Open Access Journals (Sweden)

    David Acuña-Marrero

    Full Text Available The potential effectiveness of marine protected areas (MPAs as a conservation tool for large sharks has been questioned due to the limited spatial extent of most MPAs in contrast to the complex life history and high mobility of many sharks. Here we evaluated the movement dynamics of a highly migratory apex predatory shark (tiger shark Galeocerdo cuvier at the Galapagos Marine Reserve (GMR. Using data from satellite tracking passive acoustic telemetry, and stereo baited remote underwater video, we estimated residency, activity spaces, site fidelity, distributional abundances and migration patterns from the GMR and in relation to nesting beaches of green sea turtles (Chelonia mydas, a seasonally abundant and predictable prey source for large tiger sharks. Tiger sharks exhibited a high degree of philopatry, with 93% of the total satellite-tracked time across all individuals occurring within the GMR. Large sharks (> 200 cm TL concentrated their movements in front of the two most important green sea turtle-nesting beaches in the GMR, visiting them on a daily basis during nocturnal hours. In contrast, small sharks (< 200 cm TL rarely visited turtle-nesting areas and displayed diurnal presence at a third location where only immature sharks were found. Small and some large individuals remained in the three study areas even outside of the turtle-nesting season. Only two sharks were satellite-tracked outside of the GMR, and following long-distance migrations, both individuals returned to turtle-nesting beaches at the subsequent turtle-nesting season. The spatial patterns of residency and site fidelity of tiger sharks suggest that the presence of a predictable source of prey and suitable habitats might reduce the spatial extent of this large shark that is highly migratory in other parts of its range. This highly philopatric behaviour enhances the potential effectiveness of the GMR for their protection.

  10. Ocean Warming and CO2-Induced Acidification Impact the Lipid Content of a Marine Predatory Gastropod

    Directory of Open Access Journals (Sweden)

    Roselyn Valles-Regino

    2015-09-01

    Full Text Available Ocean warming and acidification are current global environmental challenges impacting aquatic organisms. A shift in conditions outside the optimal environmental range for marine species is likely to generate stress that could impact metabolic activity, with consequences for the biosynthesis of marine lipids. The aim of this study was to investigate differences in the lipid content of Dicathais orbita exposed to current and predicted future climate change scenarios. The whelks were exposed to a combination of temperature and CO2-induced acidification treatments in controlled flowthrough seawater mesocosms for 35 days. Under current conditions, D. orbita foot tissue has an average of 6 mg lipid/g tissue, but at predicted future ocean temperatures, the total lipid content dropped significantly, to almost half. The fatty acid composition is dominated by polyunsaturated fatty acids (PUFA 52% with an n-3:6 fatty acid ratio of almost 2, which remains unchanged under future ocean conditions. However, we detected an interactive effect of temperature and pCO2 on the % PUFAs and n-3 and n-6 fatty acids were significantly reduced by elevated water temperature, while both the saturated and monounsaturated fatty acids were significantly reduced under increased pCO2 acidifying conditions. The present study indicates the potential for relatively small predicted changes in ocean conditions to reduce lipid reserves and alter the fatty acid composition of a predatory marine mollusc. This has potential implications for the growth and survivorship of whelks under future conditions, but only minimal implications for human consumption of D. orbita as nutritional seafood are predicted.

  11. Subsurface observations of white shark Carcharodon carcharias predatory behaviour using an autonomous underwater vehicle.

    Science.gov (United States)

    Skomal, G B; Hoyos-Padilla, E M; Kukulya, A; Stokey, R

    2015-12-01

    In this study, an autonomous underwater vehicle (AUV) was used to test this technology as a viable tool for directly observing the behaviour of marine animals and to investigate the behaviour, habitat use and feeding ecology of white sharks Carcharodon carcharias near Guadalupe Island off the coast of Mexico. During the period 31 October to 7 November 2013, six AUV missions were conducted to track one male and three female C. carcharias, ranging in estimated total length (LT ) from 3·9 to 5·7 m, off the north-east coast of Guadalupe Island. In doing so, the AUV generated over 13 h of behavioural data for C. carcharias at depths down to 90 m. The sharks remained in the area for the duration of each mission and moved through broad depth and temperature ranges from the surface to 163·8 m depth (mean ± S.D. = 112·5 ± 40·3 m) and 7·9-27·1° C (mean ± S.D. = 12·7 ± 2·9° C), respectively. Video footage and AUV sensor data revealed that two of the C. carcharias being tracked and eight other C. carcharias in the area approached (n = 17), bumped (n = 4) and bit (n = 9) the AUV during these tracks. This study demonstrated that an AUV can be used to effectively track and observe the behaviour of a large pelagic animal, C. carcharias. In doing so, the first observations of subsurface predatory behaviour were generated for this species. At its current state of development, this technology clearly offers a new and innovative tool for tracking the fine-scale behaviour of marine animals. © 2015 The Fisheries Society of the British Isles.

  12. Optimization an optimal artificial diet for the predatory bug Orius sauteri (hemiptera: anthocoridae.

    Directory of Open Access Journals (Sweden)

    Xiao-Ling Tan

    Full Text Available BACKGROUND: The flower bug Orius sauteri is an important polyphagous predator that is widely used for the biological control of mites and aphids. However, the optimal conditions for mass rearing of this insect are still unclear, thus limiting its application. METHODOLOGY: In this study, we investigated the optimal ingredients of an artificial diet for raising O. sauteri using a microencapsulation technique. The ingredients included egg yolk (vitellus, whole-pupa homogenate of the Tussah silk moth (Antheraea paphia, honey, sucrose, rapeseed (Brassica napus pollen and sinkaline. We tested 25 combinations of the above ingredients using an orthogonal experimental design. Using statistical analysis, we confirmed the main effect factors amongst the components, and selected five optimal combinations based on different biological and physiological characters. PRINCIPAL FINDINGS: The results showed that, although different artificial diet formats significantly influenced the development and reproductive ability of O. sauteri, the complete development of O. sauteri to sexual maturity could only be achieved by optimizing the artificial diet according to specific biological characters. In general, pupae of A. paphia had more influence on O sauteri development than did artificial components. The results of a follow-up test of locomotory and respiratory capacity indicated that respiratory quotient, metabolic rate and average creeping speed were all influenced by different diets. Furthermore, the field evaluations of mating preference, predatory consumption and population dispersion also demonstrated the benefits that could be provided by optimal artificial diets. CONCLUSIONS: A microencapsulated artificial diet overcame many of the difficulties highlighted by previous studies on the mass rearing of O. sauteri. Optimization of the microencapsulated artificial diet directly increased the biological and physiological characters investigated. Successive

  13. Selectivity of diacylhydrazine insecticides to the predatory bug Orius laevigatus: in vivo and modelling/docking experiments.

    Science.gov (United States)

    Amor, Fermín; Christiaens, Olivier; Bengochea, Paloma; Medina, Pilar; Rougé, Pierre; Viñuela, Elisa; Smagghe, Guy

    2012-12-01

    Knowledge of pesticide selectivity to natural enemies is necessary for a successful implementation of biological and chemical control methods in integrated pest management (IPM) programmes. Diacylhydrazine (DAH)-based ecdysone agonists, also known as moulting-accelerating compounds (MACs), are considered to be a selective group of insecticides, and their compatibility with predatory Heteroptera, which are used as biological control agents, is known. However, their molecular mode of action has not been explored in beneficial insects such as Orius laevigatus (Fieber) (Hemiptera: Anthocoridae). In this project, in vivo toxicity assays demonstrated that the DAH-based RH-5849, tebufenozide and methoxyfenozide have no toxic effect against O. laevigatus. The ligand-binding domain (LBD) of the ecdysone receptor (EcR) of O. laevigatus was sequenced, and a homology protein model was constructed that confirmed a cavity structure with 12 α-helices, harbouring the natural insect moulting hormone 20-hydroxyecdysone. However, docking studies showed that a steric clash occurred for the DAH-based insecticides owing to a restricted extent of the ligand-binding cavity of the EcR of O. laevigatus. The insect toxicity assays demonstrated that MACs are selective for O. laevigatus. The modelling/docking experiments are indications that these pesticides do not bind with the LBD-EcR of O. laevigatus and support the supposition that they show no biological effects in the predatory bug. These data help in explaining the compatible use of MACs together with predatory bugs in IPM programmes. Copyright © 2012 Society of Chemical Industry.

  14. Warring arthropod societies: Social spider colonies can delay annihilation by predatory ants via reduced apparency and increased group size.

    Science.gov (United States)

    Keiser, Carl N; Wright, Colin M; Pruitt, Jonathan N

    2015-10-01

    Sociality provides individuals with benefits via collective foraging and anti-predator defense. One of the costs of living in large groups, however, is increased apparency to natural enemies. Here, we test how the individual-level and collective traits of spider societies can increase the risk of discovery and death by predatory ants. We transplanted colonies of the social spider Stegodyphus dumicola into a habitat dense with one of their top predators, the pugnacious ant Anoplolepis custodiens. With three different experiments, we test how colony-wide survivorship in a predator-dense habitat can be altered by colony apparency (i.e., the presence of a capture web), group size, and group composition (i.e., the proportion of bold and shy personality types present). We also test how spiders' social context (i.e., living solitarily vs. among conspecifics) modifies their behaviour toward ants in their capture web. Colonies with capture webs intact were discovered by predatory ants on average 25% faster than colonies with the capture web removed, and all discovered colonies eventually collapsed and succumbed to predation. However, the lag time from discovery by ants to colony collapse was greater for colonies containing more individuals. The composition of individual personality types in the group had no influence on survivorship. Spiders in a social group were more likely to approach ants caught in their web than were isolated spiders. Isolated spiders were more likely to attack a safe prey item (a moth) than they were to attack ants and were more likely to retreat from ants after contact than they were after contact with moths. Together, our data suggest that the physical structures produced by large animal societies can increase their apparency to natural enemies, though larger groups can facilitate a longer lag time between discovery and demise. Lastly, the interaction between spiders and predatory ants seems to depend on the social context in which spiders reside

  15. Cover Crop Species and Management Influence Predatory Arthropods and Predation in an Organically Managed, Reduced-Tillage Cropping System.

    Science.gov (United States)

    Rivers, Ariel N; Mullen, Christina A; Barbercheck, Mary E

    2018-04-05

    Agricultural practices affect arthropod communities and, therefore, have the potential to influence the activities of arthropods. We evaluated the effect of cover crop species and termination timing on the activity of ground-dwelling predatory arthropods in a corn-soybean-wheat rotation in transition to organic production in Pennsylvania, United States. We compared two cover crop treatments: 1) hairy vetch (Vicia villosa Roth) planted together with triticale (×Triticosecale Wittmack) after wheat harvest, and 2) cereal rye (Secale cereale Linnaeus) planted after corn harvest. We terminated the cover crops in the spring with a roller-crimper on three dates (early, middle, and late) based on cover crop phenology and standard practices for cash crop planting in our area. We characterized the ground-dwelling arthropod community using pitfall traps and assessed relative predation using sentinel assays with live greater waxworm larvae (Galleria mellonella Fabricius). The activity density of predatory arthropods was significantly higher in the hairy vetch and triticale treatments than in cereal rye treatments. Hairy vetch and triticale favored the predator groups Araneae, Opiliones, Staphylinidae, and Carabidae. Specific taxa were associated with cover crop condition (e.g., live or dead) and termination dates. Certain variables were positively or negatively associated with the relative predation on sentinel prey, depending on cover crop treatment and stage, including the presence of predatory arthropods and various habitat measurements. Our results suggest that management of a cover crop by roller-crimper at specific times in the growing season affects predator activity density and community composition. Terminating cover crops with a roller-crimper can conserve generalist predators.

  16. Invitations received from potential predatory publishers and fraudulent conferences: a 12-month early-career researcher experience.

    Science.gov (United States)

    Mercier, Eric; Tardif, Pier-Alexandre; Moore, Lynne; Le Sage, Natalie; Cameron, Peter A

    2018-02-01

    This study aims to describe all unsolicited electronic invitations received from potential predatory publishers or fraudulent conferences over a 12-month period following the first publication as a corresponding author of a junior academician. Unsolicited invitations received at an institutional email address and perceived to be sent by predatory publishers or fraudulent conferences were collected. A total of 502 invitations were included of which 177 (35.3%) had subject matter relevant to the recipient's research interests and previous work. Two hundred and thirty-seven were invitations to publish a manuscript. Few disclosed the publication fees (32, 13.5%) but they frequently reported accepting all types of manuscripts (167, 70.5%) or emphasised on a deadline to submit (165, 69.6%). Invitations came from 39 publishers (range 1 to 87 invitations per publisher). Two hundred and ten invitations from a potential fraudulent conference were received. These meetings were held in Europe (97, 46.2%), North America (65, 31.0%), Asia (20.4%) or other continents (5, 2.4%) and came from 18 meeting organisation groups (range 1 to 137 invitations per organisation). Becoming an editorial board member (30), the editor-in-chief (1), a guest editor for journal special issue (6) and write a book chapter (11) were some of the roles offered in the other invitations included while no invitation to review a manuscript was received. Young researchers are commonly exposed to predatory publishers and fraudulent conferences following a single publication as a corresponding author. Academic institutions worldwide need to educate and inform young researchers of this emerging problem. © Article author(s) (or their employer(s) unless otherwise stated in the text of the article) 2018. All rights reserved. No commercial use is permitted unless otherwise expressly granted.

  17. Differential impact of dimethoate on the predatory mite Hypoaspis aculeifer Canestrini (Gamasida: Laelapidae) exposed at different life stages

    DEFF Research Database (Denmark)

    Heckmann, Lars-Henrik; Krogh, P. H.

    The acute toxicity of dimethoate was examined on different life stages (larvae, protonymph, deutonymph, male and female) of the predatory mite Hypoaspis aculeifer. The mites were exposed for 7 days in an artificial soil to 0, 2, 4, and 6 mg kg-1. A comparison of LC50 values ranked the sensitivity...... of the life stages to be: Larvae (LC50 = 3.8) > protonymph (LC50 = 5.3) > male (LC50 = 5.6) > deutonymph (LC50 = 7.1) > female (LC50 = 7.6). A life table response analysis may show how the results affect the population dynamics of H. aculeifer....

  18. Comparative analyses of contaminant levels in bottom feeding and predatory fish using the National Contaminant Biomonitoring Program data

    Energy Technology Data Exchange (ETDEWEB)

    Kidwell, J.M. [Clement International Corp., Fairfax, VA (United States); Phillips, L.J. [Versar Inc., Springfield, VA (United States); Birchard, G.F. [George Mason Univ., Fairfax, VA (United States)

    1995-06-01

    Both bottom feeding and predatory fish accumulate chemical contaminants found in water. Bottom feeders are readily exposed to the greater quantities of chlorinated hydrocarbons and metals that accumulate in sediments. Predators, on the other hand, may bioaccumulate organochlorine pesticides, PCBs, and metals from the surrounding water or from feeding on other fish, including bottom feeders, which may result in the biomagnification of these compounds in their tissues. This study used National Contaminant Biomonitoring Program data produced by the Fish and Wildlife Service to test the hypothesis that differences exist between bottom feeders and predators in tissue levels of organochlorine pesticides, PCBs, and metals. 7 refs., 2 tabs.

  19. The residual and direct effects of reduced-risk and conventional miticides on twospotted spider mites, Tetranychus urticae (Acari: Tetranychidae) and predatory mites (Acari: Phytoseiidae)

    International Nuclear Information System (INIS)

    Liburd, O.E.; White, J.C.; Rhodes, E.M.; Browdy, A.A.

    2007-01-01

    The residual effects of several reduced-risk and conventional miticides were evaluated in strawberries (Fragaria × ananassa Duchesne) on the twospotted spider mite (TSSM), Tetranychus urticae Koch (Acari: Tetranychidae) and on 2 predatory mites, Neoseiulus californicus McGregor and Phytoseiulus persimilis Athias-Henriot (Acari: Phytoseiidae). Experiments were conducted in the laboratory and greenhouse. The greenhouse experiments also tested the direct effects of the miticides on TSSM. The efficacy of conventional and reduced-risk miticides was evaluated on strawberry leaf discs and on whole plants for control of TSSM. Furthermore, the residual effects of these miticides were evaluated on whole strawberry plants against selective predatory mites. For TSSM, 5 treatments were evaluated: a conventional miticide; fenbutatin-oxide (Vendex[reg]) and 3 reduced-risk miticides; binfenazate (Acramite 50WP[reg]), activated garlic extract (Repel[reg]), sesame seed and castor oil (Wipeout[reg]), and a water-treated control. For predatory mites, the residual effects of only Acramite[reg] and Vendex[reg] were evaluated. Acramite[reg] was the most effective acaricide in reducing TSSM populations in both the laboratory and greenhouse experiments. Vendex[reg] and Wipeout[reg] were also effective in the laboratory, but did not cause significant reduction of TSSM in the greenhouse. Repel[reg] was the least effective of the 4 pesticides evaluated. Neither Acramite[reg] nor Vendex[reg] had a significant effect on either predatory mite species. However, there appeared to be more predatory mites on the Vendex[reg]-treated plants than on the Acramite[reg]-treated plants. There were significantly more predatory mites of both species on the cue plants, which were inoculated with TSSM versus the non-cue plants, which were not inoculated. (author) [es

  20. Food resource and temporal partitioning amongst a guild of predatory agroecosystem - inhabiting ant species

    Directory of Open Access Journals (Sweden)

    Vivek Mohan AGARWAL, Neelkamal RASTOGI

    2009-10-01

    Full Text Available Prey diversity and temporal foraging patterns of six abundant, predatory ant species were investigated seasonally in an agroecosystem with two main vegetable crops. Pheidole sp. demonstrated the highest predation success and therefore appears to be the dominant species while Tapinoma melanocephalum showed the lowest success under the natural field conditions. Investigation of prey diversity and temporal activity patterns with the null model tests of niche overlap revealed a significant overlap indicating that the activity periods and prey diversity may not be solely influenced by interactions among the co-existing ant species. However, niche partitioning in the daily peak activity periods was demonstrated during all the three seasons (summer, rainy and winter particularly between Pheidole sp. and T. melanocephalum. Pheidole sp. exhibited a high intensity, broadly extended mono-modal foraging pattern. Camponotus compressus and C. paria showed bi-modality in their foraging activity during the rainy season and mono-modal patterns during summer and winter seasons. Pachycondyla tesserinoda, Tetramorium sp. and T. melanocephalum exhibited peak foraging activities in the morning hours during the summer and rainy seasons. The activity profiles of C. compressus and T. melanocephalum were skewed towards late afternoon hours during the winter season indicating avoidance of foraging activity during the favourable periods when the more aggressive Pheidole sp. is active. In the sponge gourd agroecosystem, the ants captured predominantly hymenopteran, orthopteran and coleopteran insects. While Pheidole sp. hunted mainly the large orthopteran prey, other ant species captured worker ants in the sponge gourd agroecosystem. In the cauliflower agroecosystem, while other species captured prey chiefly belonging to six orders, i.e., Lepidoptera, Hymenoptera, Coleoptera, Hemiptera, Isoptera and Diptera, Pheidole sp. was the only species to also hunt orthopteran prey

  1. Etoxazole resistance in predatory mite Phytoseiulus persimilis A.-H. (Acari: Phytoseiidae): Cross-resistance, inheritance and biochemical resistance mechanisms.

    Science.gov (United States)

    Yorulmaz Salman, Sibel; Aydınlı, Fatma; Ay, Recep

    2015-07-01

    Phytoseiulus persimilis of the family Phytoseiidae is an effective predatory mite species that is used to control pest mites. The LC50 and LC60 values of etoxazole were determined on P. persimilis using a leaf-disc method and spraying tower. A laboratory selection population designated ETO6 was found to have a 111.63-fold resistance to etoxazole following 6 selection cycles. This population developed low cross-resistance to spinosad, spiromesifen, acetamiprid, indoxacarb, chlorantraniliprole, milbemectin and moderate cross-resistance to deltamethrin. PBO, IBP and DEM synergised resistance 3.17-, 2.85- and 3.60-fold respectively. Crossing experiments revealed that etoxazole resistance in the ETO6 population was an intermediately dominant and polygenic. In addition, detoxifying enzyme activities were increased 2.71-fold for esterase, 3.09-fold for glutathione S-transferase (GST) and 2.76-fold for cytochrome P450 monooxygenase (P450) in the ETO6 population. Selection for etoxazole under laboratory conditions resulted in the development of etoxazole resistance in the predatory mite P. persimilis that are resistant to pesticides are considered valuable for use in resistance management programmes within integrated pest control strategies. Copyright © 2014 Elsevier Inc. All rights reserved.

  2. Social Familiarity Reduces Reaction Times and Enhances Survival of Group-Living Predatory Mites under the Risk of Predation

    Science.gov (United States)

    Strodl, Markus Andreas; Schausberger, Peter

    2012-01-01

    Background Social familiarity, which is based on the ability to recognise familiar conspecific individuals following prior association, may affect all major life activities of group-living animals such as foraging, reproduction and anti-predator behaviours. A scarcely experimentally tested explanation why social familiarity is beneficial for group-living animals is provided by limited attention theory. Limited attention theory postulates that focusing on a given task, such as inspection and assessment of unfamiliar group members, has cognitive and associated physiological and behavioural costs with respect to the attention paid to other tasks, such as anti-predator vigilance and response. Accordingly, we hypothesised that social familiarity enhances the anti-predator success of group-living predatory mites, Phytoseiulus persimilis, confronted with an intraguild predator, the predatory mite Amblyseius andersoni. Methodology/Principal Findings We videotaped and analysed the response of two P. persimilis larvae, held in familiar or unfamiliar pairs, to attacks by a gravid A. andersoni female, using the behavioural analyses software EthoVision Pro®. Familiar larvae were more frequently close together, reacted more quickly to predator attacks, survived more predator encounters and survived longer than unfamiliar larvae. Significance In line with the predictions of limited attention theory, we suggest that social familiarity improves anti-predator behaviours because it allows prey to shift attention to other tasks rather than group member assessment. PMID:22927997

  3. Evaluation of predatory mites and Acramite for control of twospotted spider mites in strawberries in north central Florida.

    Science.gov (United States)

    Rhodes, Elena M; Liburd, Oscar E

    2006-08-01

    Greenhouse and field experiments were conducted from 2003 to 2005 to determine the effectiveness of two predatory mite species, Phytoseiulus persimilis Athias-Henriot and Neoseiulus californicus (McGregor), and a reduced-risk miticide, Acramite 50 WP (bifenazate), for control of twospotted spider mite, Tetranychus urticae Koch, in strawberries (Fragaria x ananassa Duchesne). In greenhouse tests, three treatments consisting of releases of P. persimilis, N. californicus, and an untreated control were evaluated. Both species of predatory mites significantly reduced twospotted spider mite numbers below those found in the control during the first 3 wk of evaluation. However, during week 4, twospotted spider mite numbers on the plants treated with P. persimilis increased and did not differ significantly from the control. Field studies used releases of P. persimilis and N. californicus, applications of Acramite, and untreated control plots. Both N. californicus and P. persimilis significantly reduced populations of twospotted spider mite below numbers recorded in the control plots. During the 2003-2004 field season P. persimilis took longer than N. californicus to bring the twospotted spider mite population under control (< 10 mites per leaflet). Acramite was effective in reducing twospotted spider mite populations below 10 mites per leaflet during the 2003-2004 field season but not during the 2004-2005 field season, possibly because of a late application. These findings indicate that N. californicus releases and properly timed Acramite applications are promising options for twospotted spider mite control in strawberries for growers in north Florida and other areas of the southeast.

  4. A Modular Cage System Design for Continuous Medium to Large Scale In Vivo Rearing of Predatory Mites (Acari: Phytoseiidae

    Directory of Open Access Journals (Sweden)

    Juan Alfredo Morales-Ramos

    2014-01-01

    Full Text Available A new stackable modular system was developed for continuous in vivo production of phytoseiid mites. The system consists of cage units that are filled with lima beans,  Phaseolus lunatus, or red beans, P. vulgaris, leaves infested with high levels of the two-spotted spider mites, Tetranychus urticae. The cage units connect with each other through a connection cup, which also serves for monitoring and collection. Predatory mites migrate upwards to new cage units as prey is depleted. The system was evaluated for production of Phytoseiulus persimilis. During a 6-month experimental period, 20,894.9±10,482.5 (mean ± standard deviation predators were produced per week. The production consisted of 4.1±4.6% nymphs and 95.9±4.6% adults. A mean of 554.5±59.8 predatory mites were collected per harvested cage and the mean interval length between harvests was 6.57±6.76 days. The potential for commercial and experimental applications is discussed.

  5. Driving factors of the communities of phytophagous and predatory mites in a physic nut plantation and spontaneous plants associated.

    Science.gov (United States)

    Cruz, Wilton P; Sarmento, Renato A; Teodoro, Adenir V; Neto, Marçal P; Ignacio, Maíra

    2013-08-01

    Seasonal changes in climate and plant diversity are known to affect the population dynamics of both pests and natural enemies within agroecosystems. In Brazil, spontaneous plants are usually tolerated in small-scale physic nut plantations over the year, which in turn may mediate interactions between pests and natural enemies within this agroecosystem. Here, we aimed to access the influence of seasonal variation of abiotic (temperature, relative humidity and rainfall) and biotic (diversity of spontaneous plants, overall richness and density of mites) factors on the communities of phytophagous and predatory mites found in a physic nut plantation and its associated spontaneous plants. Mite sampling was monthly conducted in dicotyledonous and monocotyledonous leaves of spontaneous plants as well as in physic nut shrubs over an entire year. In the dry season there was a higher abundance of phytophagous mites (Tenuipalpidae, Tarsonemidae and Tetranychidae) on spontaneous plants than on physic nut shrubs, while predatory mites (Phytoseiidae) showed the opposite pattern. The overall density of mites on spontaneous plants increased with relative humidity and diversity of spontaneous plants. Rainfall was the variable that most influenced the density of mites inhabiting physic nut shrubs. Agroecosystems comprising spontaneous plants associated with crops harbour a rich mite community including species of different trophic levels which potentially benefit natural pest control due to increased diversity and abundance of natural enemies.

  6. Social familiarity reduces reaction times and enhances survival of group-living predatory mites under the risk of predation.

    Directory of Open Access Journals (Sweden)

    Markus Andreas Strodl

    Full Text Available Social familiarity, which is based on the ability to recognise familiar conspecific individuals following prior association, may affect all major life activities of group-living animals such as foraging, reproduction and anti-predator behaviours. A scarcely experimentally tested explanation why social familiarity is beneficial for group-living animals is provided by limited attention theory. Limited attention theory postulates that focusing on a given task, such as inspection and assessment of unfamiliar group members, has cognitive and associated physiological and behavioural costs with respect to the attention paid to other tasks, such as anti-predator vigilance and response. Accordingly, we hypothesised that social familiarity enhances the anti-predator success of group-living predatory mites, Phytoseiulus persimilis, confronted with an intraguild predator, the predatory mite Amblyseius andersoni.We videotaped and analysed the response of two P. persimilis larvae, held in familiar or unfamiliar pairs, to attacks by a gravid A. andersoni female, using the behavioural analyses software EthoVision Pro®. Familiar larvae were more frequently close together, reacted more quickly to predator attacks, survived more predator encounters and survived longer than unfamiliar larvae.In line with the predictions of limited attention theory, we suggest that social familiarity improves anti-predator behaviours because it allows prey to shift attention to other tasks rather than group member assessment.

  7. Comparative larval growth and mortality of mesopelagic fishes and their predatory impact on zooplankton in the Kuroshio region

    Science.gov (United States)

    Sassa, Chiyuki; Takahashi, Motomitsu

    2018-01-01

    Larvae of mesopelagic fishes usually dominate in oceanic larval fish assemblages, but detailed investigations of their ecology are limited and thus preclude full assessment of the ecosystem structure and dynamics in oceanic waters. Here, we examined the growth and mortality of six taxa of numerically dominant mesopelagic fish larvae and their predatory impact on zooplankton in the Kuroshio region off southern Japan during late winter. The weight-specific growth coefficient (Gw) ranged from 0.077 (Sigmops gracilis) to 0.156 d-1 (Vinciguerria nimbaria), and the instantaneous daily mortality coefficient (M) from 0.067 (S. gracilis) to 0.143 d-1 (Myctophum asperum). The ratio Gw/M, an index of stage-specific survival of the larvae, was from 0.90 (Notoscopelus japonicus) to 1.24 (V. nimbaria), without a significant difference from a value of 1 in all species. Based on the reported relationship between Gw and ingestion rate of the larval fishes, the daily ration of each species was calculated to be 32-57% of body dry weight d-1. Mean and 95% confidence interval of food requirements of the six taxa of larvae was 1.41 ± 0.55 mg C m-2 d-1. Predatory impact of the mesopelagic fish larvae on the production rate of the available prey was estimated to be approximately 3.5-5.2%, implying that the larvae have a low level but consistent effect on zooplankton production in the oligotrophic Kuroshio region.

  8. ISIS Child Soldiers in Syria: The Structural and Predatory Recruitment, Enlistment, Pre-Training Indoctrination, Training, and Deployment

    Directory of Open Access Journals (Sweden)

    Asaad Almohammad

    2018-02-01

    Full Text Available Research on the engagement of children with the so-called Islamic State (a.k.a. ISIS relies heavily on the analysis of obtained ISIS documents and ISIS-disseminated propaganda, leaving major elements of the recruitment and deployment process uncovered. Such ambiguities hinder future efforts aimed at dealing with ISIS’ child soldiers. As such, an intensive effort to compile data using interviews and naturalistic observations across ISIS-held territories in Syria was made to exhaustively explore the process of child recruitment and deployment by ISIS. Findings suggest that there are two methods of recruitment: predatory and structural. The enlistment, intensity of indoctrination, types of training, and nature of deployment were found to depend, to a high degree, on the type of recruitment (i.e., predatory or structural, and category of children based on their origin (i.e., local, Middle Eastern and North African [MENA], or foreign and if they are orphans. The data shows that the separation between children and adults’ roles/assignments is diminishing. After a thorough exploration of the elements of ISIS’ recruitment and deployment process, this paper argues its findings, implications, and limitations.

  9. Below-ground plant parts emit herbivore-induced volatiles: olfactory responses of a predatory mite to tulip bulbs infested by rust mites

    NARCIS (Netherlands)

    Aratchige, N.S.; Lesna, I.; Sabelis, M.W.

    2004-01-01

    Although odour-mediated interactions among plants, spider mites and predatory mites have been extensively studied above-ground, belowground studies are in their infancy. In this paper, we investigate whether feeding by rust mites (Aceria tulipae) cause tulip bulbs to produce odours that attract

  10. Functional responses and prey-stage preferences of a predatory gall midge and two predacious mites wtih twospotted spider mites, Tetranychus urticae as host

    Science.gov (United States)

    The twospotted spider mite, Tetranychus urticae (Acari: Tetranychidae), is an important pest of vegetables and other crops. This study was conducted to evaluate and compare the potential role of three commercially available predators, predatory gall midge, Feltiella acarisuga (Vallot) (Diptera: Ceci...

  11. Ecological and spatial factors drive intra- and interspecific variation in exposure of subarctic predatory bird nestlings to persistent organic pollutants.

    Science.gov (United States)

    Eulaers, Igor; Jaspers, Veerle L B; Bustnes, Jan O; Covaci, Adrian; Johnsen, Trond V; Halley, Duncan J; Moum, Truls; Ims, Rolf A; Hanssen, Sveinn A; Erikstad, Kjell E; Herzke, Dorte; Sonne, Christian; Ballesteros, Manuel; Pinxten, Rianne; Eens, Marcel

    2013-07-01

    Top predators in northern ecosystems may suffer from exposure to persistent organic pollutants (POPs) as this exposure may synergistically interact with already elevated natural stress in these ecosystems. In the present study, we aimed at identifying biological (sex, body condition), ecological (dietary carbon source, trophic level) and spatial factors (local habitat, regional nest location) that may influence intra- and interspecific variation in exposure of subarctic predatory bird nestlings to polychlorinated biphenyl 153 (CB 153), polybrominated diphenyl ether 47 (BDE 47), dichlorodiphenyldichloroethylene (p,p'-DDE) and hexachlorobenzene (HCB). During three breeding seasons (2008-2010), we sampled body feathers from fully-grown nestlings of three ecologically distinct predatory bird species in subarctic Norway: Northern Goshawk (Accipiter gentilis), White-tailed Eagle (Haliaeetus albicilla) and Golden Eagle (Aquila chrysaetos). The present study analysed, for the first time, body feathers for both POPs and carbon (δ(13)C) and nitrogen (δ(15)N) stable isotopes, thus integrating the dietary carbon source, trophic level and POP exposure for the larger part of the nestling stage. Intraspecific variation in exposure was driven by a combination of ecological and spatial factors, often different for individual compounds. In addition, combinations for individual compounds differed among species. Trophic level and local habitat were the predominant predictors for CB 153, p,p'-DDE and BDE 47, indicating their biomagnification and decreasing levels according to coast>fjord>inland. Variation in exposure may also have been driven by inter-annual variation arisen from primary sources (e.g. p,p'-DDE) and/or possible revolatilisation from secondary sources (e.g. HCB). Interspecific differences in POP exposure were best explained by a combination of trophic level (biomagnification), dietary carbon source (food chain discrimination) and regional nest location (historical POP

  12. The development of laboratory and semi-field methods to test the effects of pesticides on predatory beetles

    International Nuclear Information System (INIS)

    Chiverton, P.; Wallin, H.

    1997-01-01

    Following the sequential testing procedure adopted by the IOBC/WPRS Working Group Pesticides and Beneficial Organisms, two simple, robust methods are presented which were designed for testing the effects of pesticides on predatory beetles. In a laboratory initial toxicity test both DDT and lindane were found harmful to the carabid Pterostichus cupreus, whereas α-endosulfan was 'harmless'. DDT was found harmless to P. melanarius. Sub-lethal doses of both DDT and lindane incorporated in prey caused P. cupreus females to produce smaller eggs. In a semi-field test it was demonstrated that Lindane reduced the beneficial capacity of P. cupreus. Climatic conditions at the time of the test however were such that the majority of test animals in control treatments escaped. Caution was therefore advised in the choice of test animal and test design for the semi-field test. (author). 7 refs, 2 figs, 3 tabs

  13. Microplastic does not magnify the acute effect of PAH pyrene on predatory performance of a tropical fish (Lates calcarifer)

    DEFF Research Database (Denmark)

    Guven, Olgac; Bach, Lis; Munk, Peter

    2018-01-01

    Microplastic (MP) leads to widespread pollution in the marine ecosystem. In addition to the physical hazard posed by ingestion of microplastic particles, concern is also on their potential as vector for transport of hydrophobic contaminants. We studied experimentally the single and interactive...... effects of microplastic and pyrene, a polycyclic aromatic hydrocarbon, on the swimming behaviour and predatory performance of juvenile barramundi (Lates calcarifer). Juveniles (18+ days post hatch) were exposed to MPs, or pyrene (100nM), or combination of both and feeding rate and foraging activity...... no effect on feeding while swimming speed showed a significant decrease. Thus, our results confirm that short-time exposure to pyrene impacts performance of fish juveniles, while additional exposure to microplastic influenced their activity but not their feeding rate at the given conditions. Further studies...

  14. Smells familiar: group-joining decisions of predatory mites are mediated by olfactory cues of social familiarity.

    Science.gov (United States)

    Muleta, Muluken G; Schausberger, Peter

    2013-09-01

    Group-living animals frequently have to trade off the costs and benefits of leaving an established group and joining another group. Owing to their high fitness relevance, group-joining decisions are commonly nonrandom and may be based on traits of both individual members and the group such as life stage, body size, social status and group density or size, respectively. Many group-living animals are able to recognize and to associate preferentially with familiar individuals, i.e. those encountered before. Hence, after dispersing from established groups, animals commonly have to decide whether to join a new familiar or unfamiliar group. Using binary choice situations we assessed the effects of social familiarity on group-joining behaviour of the plant-inhabiting predatory mite Phytoseiulus persimilis . Group living in P. persimilis is brought about by the patchy distribution of its spider mite prey and mutual conspecific attraction. In the first experiment, gravid predator females given a choice between spider mite patches occupied by unfamiliar and familiar groups of females strongly preferred to join familiar groups and to deposit their eggs in these patches. Preference for socially familiar groups was robust across biases of spider mite prey densities between choice options. The second experiment revealed that the predatory mite females can smell social familiarity from a distance. Females subjected to odour choice situations in artificial cages were more strongly attracted to the odour of familiar than unfamiliar groups. We argue that P. persimilis females preferentially join socially familiar groups because a familiar social environment relaxes competition and optimizes foraging and reproduction.

  15. Sublethal effects of fenpyroximate and pyridaben on two predatory mite species, Neoseiulus womersleyi and Phytoseiulus persimilis (Acari, Phytoseiidae).

    Science.gov (United States)

    Park, Jung-Joon; Kim, Minsik; Lee, Joon-Ho; Shin, Key-Il; Lee, Sung Eun; Kim, Jeong-Gyu; Cho, Kijong

    2011-07-01

    Laboratory bioassays were conducted to evaluate the sublethal effects of fenpyroximate and pyridaben on life-table parameters of two predatory mites species, Neoseiulus (= Amblyseius) womersleyi and Phytoseiulus persimilis. In these assays, young adult females were treated with three sublethal concentrations of each acaricide. The life-table parameters were calculated at each acaricide concentration, and compared using bootstrap procedures. For each acaricide, the LC(50) estimates for both species were similar, yet the two species exhibited completely different susceptibility when the population growth rate was used as the endpoint. Exposure to both acaricides reduced the net reproduction rate (R (o)) in a concentration-dependent manner and their EC(50)s were equivalent to less than LC(7). Two different scales of population-level endpoints were estimated to compare the total effect between the species and treatments: the first endpoint values were based on the net reproductive rate (fecundity λ) and the second endpoint values incorporated the mean egg hatchability into the net reproductive rate (vitality λ). The fecundity λ decreased in a concentration-dependent manner for both acaricide treatments, but the vitality λ decreased abruptly after treatment of N. womersleyi with pyridaben. The change in the patterns of λ revealed that the acaricide effects at the population level strongly depended on the life-history characteristics of the predatory mite species and the chemical mode of action. When the total effects of the two acaricides on N. womersleyi and P. persimilis were considered, fenpyroximate was found to be the most compatible acaricide for the augmentative release of N. womersleyi after treatment.

  16. Smells familiar: group-joining decisions of predatory mites are mediated by olfactory cues of social familiarity☆

    Science.gov (United States)

    Muleta, Muluken G.; Schausberger, Peter

    2013-01-01

    Group-living animals frequently have to trade off the costs and benefits of leaving an established group and joining another group. Owing to their high fitness relevance, group-joining decisions are commonly nonrandom and may be based on traits of both individual members and the group such as life stage, body size, social status and group density or size, respectively. Many group-living animals are able to recognize and to associate preferentially with familiar individuals, i.e. those encountered before. Hence, after dispersing from established groups, animals commonly have to decide whether to join a new familiar or unfamiliar group. Using binary choice situations we assessed the effects of social familiarity on group-joining behaviour of the plant-inhabiting predatory mite Phytoseiulus persimilis. Group living in P. persimilis is brought about by the patchy distribution of its spider mite prey and mutual conspecific attraction. In the first experiment, gravid predator females given a choice between spider mite patches occupied by unfamiliar and familiar groups of females strongly preferred to join familiar groups and to deposit their eggs in these patches. Preference for socially familiar groups was robust across biases of spider mite prey densities between choice options. The second experiment revealed that the predatory mite females can smell social familiarity from a distance. Females subjected to odour choice situations in artificial cages were more strongly attracted to the odour of familiar than unfamiliar groups. We argue that P. persimilis females preferentially join socially familiar groups because a familiar social environment relaxes competition and optimizes foraging and reproduction. PMID:24027341

  17. Stage-dependent responses to emergent habitat heterogeneity: consequences for a predatory insect population in a coffee agroecosystem.

    Science.gov (United States)

    Liere, Heidi; Perfecto, Ivette; Vandermeer, John

    2014-08-01

    Interactions among members of biological communities can create spatial patterns that effectively generate habitat heterogeneity for other members in the community, and this heterogeneity might be crucial for their persistence. For example, stage-dependent vulnerability of a predatory lady beetle to aggression of the ant, Azteca instabilis, creates two habitat types that are utilized differently by the immature and adult life stages of the beetle. Due to a mutualistic association between A. instabilis and the hemipteran Coccus viridis - which is A. orbigera main prey in the area - only plants around ant nests have high C. viridis populations. Here, we report on a series of surveys at three different scales aimed at detecting how the presence and clustered distribution of ant nests affect the distribution of the different life stages of this predatory lady beetle in a coffee farm in Chiapas, Mexico. Both beetle adults and larvae were more abundant in areas with ant nests, but adults were restricted to the peripheries of highest ant activity and outside the reach of coffee bushes containing the highest densities of lady beetle larvae. The abundance of adult beetles located around trees with ants increased with the size of the ant nest clusters but the relationship is not significant for larvae. Thus, we suggest that A. orbigera undergoes an ontogenetic niche shift, not through shifting prey species, but through stage-specific vulnerability differences against a competitor that renders areas of abundant prey populations inaccessible for adults but not for larvae. Together with evidence presented elsewhere, this study shows how an important predator is not only dependent on the existence of two qualitatively distinct habitat types, but also on the spatial distribution of these habitats. We suggest that this dependency arises due to the different responses that the predator's life stages have to this emergent spatial pattern.

  18. Predatory impact of the mosquitofish (Gambusia holbrooki Girard on zooplanktonic populations in a pond at Tenuta di Castelporziano (Rome, Central Italy

    Directory of Open Access Journals (Sweden)

    Ornella FERRARA

    2001-08-01

    Full Text Available A study of a permanent pond located in a nature reserve in Central Italy was carried out over two periods (1985-87; 1995-98 to determine the structure and dynamics of planktonic biocoenosis. The composition of the zooplankton community was quite different in the two periods of study: in the first period, rotifers, small-bodied cladocerans and larval copepods were the dominant groups; in the second there was a shift from rotifers and microcrustaceans to dominance by large-bodied Daphnidae and adult copepods. The possibility is stressed that Gambusia holbrooki, present in 1985 and absent in 1995, may be responsible for the changes in the planktonic community.

  19. Egg hatching response to a range of ultraviolet-B (UV-B) radiation doses for four predatory mites and the herbivorous spider mite Tetranychus urticae.

    Science.gov (United States)

    Koveos, Dimitrios S; Suzuki, Takeshi; Terzidou, Anastasia; Kokkari, Anastasia; Floros, George; Damos, Petros; Kouloussis, Nikos A

    2017-01-01

    Egg hatchability of four predatory mites-Phytoseiulus persimilis Athias-Henriot, Iphiseius [Amblyseius] degenerans Berlese, Amblyseius swirskii Athias-Henriot, and Euseius finlandicus Oudemans (Acari: Phytoseiidae)-and the spider mite Tetranychus urticae Koch (Acari: Tetranychidae) was determined under various UV-B doses either in constant darkness (DD) or with simultaneous irradiation using white light. Under UV-B irradiation and DD or simultaneous irradiation with white light, the predator's eggs hatched in significantly lower percentages than in the control non-exposed eggs, which indicates deleterious effects of UV-B on embryonic development. In addition, higher hatchability percentages were observed under UV-B irradiation and DD in eggs of the predatory mites than in eggs of T. urticae. This might be caused by a higher involvement of an antioxidant system, shield effects by pigments or a mere shorter duration of embryonic development in predatory mites than in T. urticae, thus avoiding accumulative effects of UV-B. Although no eggs of T. urticae hatched under UV-B irradiation and DD, variable hatchability percentages were observed under simultaneous irradiation with white light, which suggests the involvement of a photoreactivation system that reduces UV-B damages. Under the same doses with simultaneous irradiation with white light, eggs of T. urticae displayed higher photoreactivation and were more tolerant to UV-B than eggs of the predatory mites. Among predators variation regarding the tolerance to UV-B effects was observed, with eggs of P. persimilis and I. degenerans being more tolerant to UV-B radiation than eggs of A. swirskii and E. finlandicus.

  20. Beyond body size: muscle biochemistry and body shape explain ontogenetic variation of anti-predatory behaviour in the lizard Salvator merianae.

    Science.gov (United States)

    de Barros, Fábio Cury; de Carvalho, José Eduardo; Abe, Augusto Shinya; Kohlsdorf, Tiana

    2016-06-01

    Anti-predatory behaviour evolves under the strong action of natural selection because the success of individuals avoiding predation essentially defines their fitness. Choice of anti-predatory strategies is defined by prey characteristics as well as environmental temperature. An additional dimension often relegated in this multilevel equation is the ontogenetic component. In the tegu Salvator merianae, adults run away from predators at high temperatures but prefer fighting when it is cold, whereas juveniles exhibit the same flight strategy within a wide thermal range. Here, we integrate physiology and morphology to understand ontogenetic variation in the temperature-dependent shift of anti-predatory behaviour in these lizards. We compiled data for body shape and size, and quantified enzyme activity in hindlimb and head muscles, testing the hypothesis that morphophysiological models explain ontogenetic variation in behavioural associations. Our prediction is that juveniles exhibit body shape and muscle biochemistry that enhance flight strategies. We identified biochemical differences between muscles mainly in the LDH:CS ratio, whereby hindlimb muscles were more glycolytic than the jaw musculature. Juveniles, which often use evasive strategies to avoid predation, have more glycolytic hindlimb muscles and are much smaller when compared with adults 1-2 years old. Ontogenetic differences in body shape were identified but marginally contributed to behavioural variation between juvenile and adult tegus, and variation in anti-predatory behaviour in these lizards resides mainly in associations between body size and muscle biochemistry. Our results are discussed in the ecological context of predator avoidance by individuals differing in body size living at temperature-variable environments, where restrictions imposed by the cold could be compensated by specific phenotypes. © 2016. Published by The Company of Biologists Ltd.

  1. Prey Preference of the Predatory Mite, Amblyseius swirskii between First Instar Western Flower Thrips Frankliniella occidentalis and Nymphs of the Twospotted Spider Mite Tetranychus urticae

    OpenAIRE

    Xu, Xuenong; Enkegaard, Annie

    2010-01-01

    The prey preference of polyphagous predators plays an important role in suppressing different species of pest insects. In this study the prey preference of the predatory mite, Amblyseius swirskii (Athias-Henriot) (Acari: Phytoseiidae) was examined between nymphs of the twospotted spider mite, Tetranychus urticae Koch (Acari: Tetranychidae) and first instar larvae of the western flower thrips, Frankliniella occidentalis (Pergande) (Thysanoptera: Thripidae), as well as between active and chrysa...

  2. The predatory mite Neoseiulus womersleyi (Acari: Phytoseiidae) follows extracts of trails left by the two-spotted spider mite Tetranychus urticae (Acari: Tetranychidae).

    Science.gov (United States)

    Shinmen, Tsubasa; Yano, Shuichi; Osakabe, Mh

    2010-10-01

    As it walks, the two-spotted spider mite Tetranychus urticae Koch (Acari: Tetranychidae) spins a trail of silk threads, that is followed by the predatory mite, Neoseiulus womersleyi Schicha (Acari: Phytoseiidae). Starved adult female N. womersleyi followed T. urticae trails laid down by five T. urticae females but did not follow a trail of one T. urticae female, suggesting that the amount of spun threads and their chemical components should correlate positively with the number of T. urticae individuals. To examine whether chemical components of T. urticae trails are responsible for the predatory mite's trail following, we collected separate T. urticae threads from the exuviae and eggs, and then washed the threads with methanol to separate chemical components from physical attributes of the threads. Female N. womersleyi did not follow T. urticae trails that had been washed with methanol but contained physical residues, but they did follow the direction to which the methanol extracts of the T. urticae trails was applied. These results suggest that the predatory mite follows chemical, not physical, attributes of T. urticae trails.

  3. 2013 status of the Lake Ontario lower trophic levels

    Science.gov (United States)

    Holeck, Kristen T.; Rudstam, Lars G.; Hotaling, Christopher; McCullough, Russ D.; Lemon, Dave; Pearsall, Web; Lantry, Jana R.; Connerton, Michael J.; LaPan, Steve; Trometer, Betsy; Lantry, Brian F.; Walsh, Maureen; Weidel, Brian C.

    2014-01-01

    Phosphorus showed high variation across nearshore (10 m depth) sites but was more stable at offshore (20 m and deeper) stations. In June and July, sites at the mouth of the Niagara River and at Oak Orchard had high phosphorus concentrations (20 – 46 μg/L). Epilimnetic average April-Oct total phosphorus (TP) ranged between 6.9 and 19.9 μg/L in the nearshore and between 5.8 and 10.2 μg/L in the offshore. Average April-Oct soluble reactive phosphorus (SRP) ranged from 0.9 to 7.3 μg/L in the nearshore and 0.8 to 1.4 μg/L in the offshore. TP and SRP were significantly higher in the nearshore than in the offshore.Spring TP has declined in the longer data series (since 1981), but not since 1995. It averaged 8.4 μg/L in the nearshore and 5.0 μg/L in the offshore in 2013—below the 10 μg/L target set by the Great Lakes Water Quality Agreement of 1978 for offshore waters of Lake Ontario.Offshore summer chlorophyll-a declined significantly in both the short- (1995-2013) and long-term (1981-2013) time series at a rate of 3-4% per year. Nearshore chlorophyll-a increased after 2003 but then declined again after 2009. Epilimnetic chlorophyll-aaveraged between 0.5 and 1.3 μg/L across sites with no difference between nearshore and offshore habitats. Average seasonal Secchi disk depth ranged from 4.5 m to 10.6 m and was higher in the offshore (average 8.1 m) than nearshore stations (6.3 m). These values are indicative of oligotrophic conditions in both habitats.In 2013, Apr/May - Oct epilimnetic zooplankton size and total biomass were significantly higher in the offshore than the nearshore. However, with the exception of Limnocalanus (higher in offshore), there were no differences between habitats for any of the zooplankton groups.Most of the zooplankton biomass was in the metalimnion and hypolimnion during the day in 2013. Between 65 and 98% of zooplankton biomass was found below the thermocline throughout the year.The predatory cladoceran Cercopagis continued to be

  4. Predatory Mite Attraction to Herbivore-induced Plant Odors is not a Consequence of Attraction to Individual Herbivore-induced Plant Volatiles

    Science.gov (United States)

    De Bruijn, Paulien J. A.; Sabelis, Maurice W.

    2008-01-01

    Predatory mites locate herbivorous mites, their prey, by the aid of herbivore-induced plant volatiles (HIPV). These HIPV differ with plant and/or herbivore species, and it is not well understood how predators cope with this variation. We hypothesized that predators are attracted to specific compounds in HIPV, and that they can identify these compounds in odor mixtures not previously experienced. To test this, we assessed the olfactory response of Phytoseiulus persimilis, a predatory mite that preys on the highly polyphagous herbivore Tetranychus urticae. The responses of the predatory mite to a dilution series of each of 30 structurally different compounds were tested. They mites responded to most of these compounds, but usually in an aversive way. Individual HIPV were no more attractive (or less repellent) than out-group compounds, i.e., volatiles not induced in plants fed upon by spider-mites. Only three samples were significantly attractive to the mites: octan-1-ol, not involved in indirect defense, and cis-3-hexen-1-ol and methyl salicylate, which are both induced by herbivory, but not specific for the herbivore that infests the plant. Attraction to individual compounds was low compared to the full HIPV blend from Lima bean. These results indicate that individual HIPV have no a priori meaning to the mites. Hence, there is no reason why they could profit from an ability to identify individual compounds in odor mixtures. Subsequent experiments confirmed that naive predatory mites do not prefer tomato HIPV, which included the attractive compound methyl salicylate, over the odor of an uninfested bean. However, upon associating each of these odors with food over a period of 15 min, both are preferred. The memory to this association wanes within 24 hr. We conclude that P. persimilis possesses a limited ability to identify individual spider mite-induced plant volatiles in odor mixtures. We suggest that predatory mites instead learn to respond to prey

  5. Growth of a deep-water, predatory fish is influenced by the productivity of a boundary current system.

    Science.gov (United States)

    Nguyen, Hoang Minh; Rountrey, Adam N; Meeuwig, Jessica J; Coulson, Peter G; Feng, Ming; Newman, Stephen J; Waite, Anya M; Wakefield, Corey B; Meekan, Mark G

    2015-03-12

    The effects of climate change on predatory fishes in deep shelf areas are difficult to predict because complex processes may govern food availability and temperature at depth. We characterised the net impact of recent environmental changes on hapuku (Polyprion oxygeneios), an apex predator found in continental slope habitats (>200 m depth) by using dendrochronology techniques to develop a multi-decadal record of growth from otoliths. Fish were sampled off temperate south-western Australia, a region strongly influenced by the Leeuwin Current, a poleward-flowing, eastern boundary current. The common variance among individual growth records was relatively low (3.4%), but the otolith chronology was positively correlated (r = 0.61, p < 0.02) with sea level at Fremantle, a proxy for the strength of the Leeuwin Current. The Leeuwin Current influences the primary productivity of shelf ecosystems, with a strong current favouring growth in hapuku. Leeuwin Current strength is predicted to decline under climate change models and this study provides evidence that associated productivity changes may flow through to higher trophic levels even in deep water habitats.

  6. Sex-specific developmental plasticity of generalist and specialist predatory mites (Acari: Phytoseiidae) in response to food stress.

    Science.gov (United States)

    Walzer, Andreas; Schausberger, Peter

    2011-03-01

    We studied developmental plasticity under food stress in three female-biased size dimorphic predatory mite species, Phytoseiulus persimilis, Neoseiulus californicus, and Amblyseius andersoni. All three species prey on two-spotted spider mites but differ in the degree of adaptation to this prey. Phytoseiulus persimilis is a specialized spider mite predator, N. californicus is a generalist with a preference for spider mites, and A. andersoni is a broad generalist. Immature predators were offered prey patches of varying density and their survival chances, dispersal tendencies, age and size at maturity measured. Amblyseius andersoni dispersed earlier from and had lower survival chances in low density prey patches than N. californicus and P. persimilis. Age at maturity was not affected by prey density in the generalist A. andersoni, whereas both the specialist P. persimilis and the generalist N. californicus accelerated development at low prey densities. Species-specific plasticity in age at maturity reflects opposite survival strategies when confronted with limited prey: to prematurely leave and search for other food (A. andersoni) or to stay and accelerate development (P. persimilis, N. californicus). In all species, size at maturity was more plastic in females than males, indicating that males incur higher fitness costs from deviations from optimal body size.

  7. State-dependent and odour-mediated anemotactic responses of the predatory mite Phytoseiulus persimilis in a wind tunnel.

    Science.gov (United States)

    Van Tilborg, Merijn; Sabelis, Maurice W; Roessingh, Peter

    2004-01-01

    Anemotaxis in the predatory mite Phytoseiulus persimilis (both well-fed and starved), has previously been studied on a wire grid under slight turbulent airflow conditions yielding weak, yet distinct, gradients in wind speed and odour concentration (Sabelis and Van der Weel 1993). Such conditions might have critically influenced the outcome of the study. We repeated these experiments, under laminar airflow conditions on a flat surface in a wind tunnel, thereby avoiding variation in wind speed and odour concentration. Treatments for starved and well-fed mites were (1) still-air without herbivore-induced plant volatiles (HIPV) (well-fed mites only), (2) an HIPV-free air stream, and (3) an air stream with HIPV (originating from Lima bean plants infested by two-spotted spider mites, Tetranychus urticae). Well-fed mites oriented in random directions in still-air without HIPV. In an air stream, starved mites always oriented upwind, whether plant odours were present or not. Well-fed mites oriented downwind in an HIPV-free air stream, but in random directions in an air stream with HIPV. Only under the last treatment our results differed from those of Sabelis and Van der Weel (1993).

  8. Air temperature optimisation for humidity-controlled cold storage of the predatory mites Neoseiulus californicus and Phytoseiulus persimilis (Acari: Phytoseiidae).

    Science.gov (United States)

    Ghazy, Noureldin Abuelfadl; Suzuki, Takeshi; Amano, Hiroshi; Ohyama, Katsumi

    2014-03-01

    Humidity-controlled cold storage, in which the water vapour pressure is saturated, can prolong the survival of the predatory mites Neoseiulus californicus (McGregor) and Phytoseiulus persimilis Athias-Henriot (Acari: Phytoseiidae). However, information on the optimum air temperature for long-term storage by this method is limited. The authors evaluated the survival of mated adult females of N. californicus and P. persimilis at 5.0, 7.5, 10.0 and 12.5 °C under saturated water vapour condition (vapour pressure deficit 0.0 kPa). N. californicus showed a longer survival time than P. persimilis at all the air temperatures. The longest mean survival time of N. californicus was 11 weeks at 7.5 °C, whereas that of P. persimilis was 8 weeks at 5.0 °C. After storage at 7.5 °C for 8 weeks, no negative effect on post-storage oviposition was observed in N. californicus, whereas the oviposition of P. persimilis stored at 5.0 °C for 8 weeks was significantly reduced. The interspecific variation in the response of these predators to low air temperature might be attributed to their natural habitat and energy requirements. These results may be useful for the long-term storage of these predators, which is required for cost-effective biological control. © 2013 Society of Chemical Industry.

  9. Mitochondrial genome analysis of the predatory mite Phytoseiulus persimilis and a revisit of the Metaseiulus occidentalis mitochondrial genome.

    Science.gov (United States)

    Dermauw, Wannes; Vanholme, Bartel; Tirry, Luc; Van Leeuwen, Thomas

    2010-04-01

    In this study we sequenced and analysed the complete mitochondrial (mt) genome of the Chilean predatory mite Phytoseiulus persimilis Athias-Henriot (Chelicerata: Acari: Mesostigmata: Phytoseiidae: Amblyseiinae). The 16 199 bp genome (79.8% AT) contains the standard set of 13 protein-coding and 24 RNA genes. Compared with the ancestral arthropod mtDNA pattern, the gene order is extremely reshuffled (35 genes changed position) and represents a novel arrangement within the arthropods. This is probably related to the presence of several large noncoding regions in the genome. In contrast with the mt genome of the closely related species Metaseiulus occidentalis (Phytoseiidae: Typhlodrominae) - which was reported to be unusually large (24 961 bp), to lack nad6 and nad3 protein-coding genes, and to contain 22 tRNAs without T-arms - the genome of P. persimilis has all the features of a standard metazoan mt genome. Consequently, we performed additional experiments on the M. occidentalis mt genome. Our preliminary restriction digests and Southern hybridization data revealed that this genome is smaller than previously reported. In addition, we cloned nad3 in M. occidentalis and positioned this gene between nad4L and 12S-rRNA on the mt genome. Finally, we report that at least 15 of the 22 tRNAs in the M. occidentalis mt genome can be folded into canonical cloverleaf structures similar to their counterparts in P. persimilis.

  10. Social familiarity relaxes the constraints of limited attention and enhances reproduction of group-living predatory mites

    Science.gov (United States)

    Strodl, Markus A; Schausberger, Peter

    2013-01-01

    In many group-living animals, within-group associations are determined by familiarity, i.e. familiar individuals, independent of genetic relatedness, preferentially associate with each other. The ultimate causes of this behaviour are poorly understood and rigorous documentation of its adaptive significance is scarce. Limited attention theory states that focusing on a given task has interrelated cognitive, behavioural and physiological costs with respect to the attention paid to other tasks. In multiple signal environments attention has thus to be shared among signals. Assuming that familiar neighbours require less attention than unfamiliar ones, associating with familiar individuals should increase the efficiency in other tasks and ultimately increase fitness. We tested this prediction in adult females of the group-living, plant-inhabiting predatory mite Phytoseiulus persimilis. We evaluated the influence of social familiarity on within-group association behaviour, activity, predation and reproduction. In mixed groups (familiar and unfamiliar), familiar predator females preferentially associated with each other. In pure groups (either familiar or unfamiliar), familiar predator females produced more eggs than unfamiliar females at similar predation rates. Higher egg production was correlated with lower activity levels, indicating decreased restlessness. In light of limited attention theory, we argue that the ability to discriminate between familiar and unfamiliar individuals and preferential association with familiar individuals confers a selective advantage because familiar social environments are cognitively and physiologically less taxing than unfamiliar social environments. PMID:24273345

  11. Influence of the webbing produced by Oligonychus ilicis (McGregor) (Acari: Tetranychidae) on associated predatory phytoseiids

    International Nuclear Information System (INIS)

    Franco, Renato A.; Reis, Paulo R.; Oliveira, Daniel C.

    2010-01-01

    Oligonychus ilicis (McGregor) is among those mite species that can cause damage to coffee plants (Coffea spp.). Species of Phytoseiidae acari are considered the most important and studied predatory mites. The objective of this study was to evaluate the effects of the webbing produced by O. ilicis on its predation by females of the phytoseiids Iphiseiodes zuluagai Denmark and Muma, Euseius citrifolius Denmark and Muma and Amblyseius herbicolus (Chant). Four bioassays were conducted, with three treatments and ten replicates. Each replicate consisted of 25 O. ilicis per experimental unit (a leaf disc of Coffea arabica) according to the tested developmental stage, in independent experiments. To spin the web, 15 adult females were put on each experimental unit for 24h; females were then removed, leaving only the web, and predators and prey to be tested were introduced. Predation was assessed after 24h. In the presence of webbing, the consumption of eggs, larvae and nymphs by I. zuluagai and eggs and larvae by E. citrifolius was lower. For A. herbicolus, egg predation was lower, but larval predation did not vary significantly and predation of nymphs and adults was higher in the presence of webbing. Predators as a whole were more efficient consuming larvae regardless of the presence of webbing. Considering the stages of O. ilicis altogether, webbing reduced the predation potential of I. zuluagai and E. citrifolius, but not of A. herbicolus. (author)

  12. Compatibility of reduced-risk insecticides with the non-target predatory mite Iphiseius degenerans (Acari: Phytoseiidae).

    Science.gov (United States)

    Döker, İsmail; Pappas, Maria L; Samaras, Konstantinos; Triantafyllou, Anneta; Kazak, Cengiz; Broufas, George D

    2015-09-01

    Iphiseius degenerans (Berlese) (Acari: Phytoseiidae) is a common predatory mite in citrus orchards in some areas of the Mediterranean basin and an important biological control agent of the thrips Frankliniella occidentalis (Pergande) in Integrated Pest Management (IPM) programmes in greenhouse crops. In this study, we evaluated the effects of the 'reduced-risk' insecticides acetamiprid, chlorantraniliprole, flubendiamide, metaflumizone, methoxyfenozide, spinetoram and thiamethoxam on I. degenerans, as a means of testing their compatibility in IPM programmes. Although all pesticides decreased immature survival, high mortality was only recorded for young larvae when exposed to acetamiprid, while metaflumizone, thiamethoxam and spinetoram resulted in intermediate lethal effects. The estimated LC50 values of acetamiprid, spinetoram and thiamethoxam for I. degenerans females were 0.52, 0.84 and 0.16-fold lower than the respective maximum recommended doses of the pesticides for field application. Although all pesticides tested significantly decreased fecundity, highest rates corresponded to the three pesticides already mentioned. Chlorantraniliprole, flubendiamide and methoxyfenozide may preliminarily be included in IPM programmes, whereas the effects of acetamiprid, metaflumizone, spinetoram and thiamethoxam on I. degenerans should be clarified in further field toxicological tests. This information could be useful for rationally planning and implementing pest management on a sustainable basis. © 2014 Society of Chemical Industry.

  13. Clathrin Heavy Chain Is Important for Viability, Oviposition, Embryogenesis and, Possibly, Systemic RNAi Response in the Predatory Mite Metaseiulus occidentalis

    Science.gov (United States)

    Wu, Ke; Hoy, Marjorie A.

    2014-01-01

    Clathrin heavy chain has been shown to be important for viability, embryogenesis, and RNA interference (RNAi) in arthropods such as Drosophila melanogaster. However, the functional roles of clathrin heavy chain in chelicerate arthropods, such as the predatory mite Metaseiulus occidentalis, remain unknown. We previously showed that dsRNA ingestion, followed by feeding on spider mites, induced systemic and robust RNAi in M. occidentalis females. In the current study, we performed a loss-of-function analysis of the clathrin heavy chain gene in M. occidentalis using RNAi. We showed that ingestion of clathrin heavy chain dsRNA by M. occidentalis females resulted in gene knockdown and reduced longevity. In addition, clathrin heavy chain dsRNA treatment almost completely abolished oviposition by M. occidentalis females and the few eggs produced did not hatch. Finally, we demonstrated that clathrin heavy chain gene knockdown in M. occidentalis females significantly reduced a subsequent RNAi response induced by ingestion of cathepsin L dsRNA. The last finding suggests that clathrin heavy chain may be involved in systemic RNAi responses mediated by orally delivered dsRNAs in M. occidentalis. PMID:25329675

  14. Phytophilous cladocerans (Crustacea, Anomopoda and Ctenopoda from Paranã River Valley, Goiás, Brazil Cladóceros fitófilos (Crustacea, Anomopoda and Ctenopoda do vale do Rio Paranã, Goiás, Brasil

    Directory of Open Access Journals (Sweden)

    Lourdes M. A. Elmoor-Loureiro

    2007-06-01

    Full Text Available A rapid assessment survey identified 39 phytophilous cladocerans species from littoral zones of rivers, permanent and temporary lagoons, and swamps of the Paranã River Valley, Goiás, Brazil, 22 are registered for the first time in Central Brazil. Aspects of the taxonomy of some of these species are discussed. Cluster analysis (UPGMA revealed two phytophilous cladoceran assemblages, characterized by higher or lower richness and relative abundance of species of the families Daphniidae and Moinidae (filter feeders, in comparison with the dominant families Chydoridae and Macrothricidae (scraper feeders.Através de amostragens rápidas, levantou-se as espécies de cladóceros fitófilos presentes em zonas litorâneas de rios, lagoas e brejos permanentes e temporários do vale do Rio Paranã, Goiás, Brasil. Foram encontradas 39 espécies, das quais 22 são registradas pela primeira vez na região central do Brasil. São discutidos aspectos da taxonomia de algumas dessas espécies. A análise de agrupamento (UPGMA dos pontos de amostragem mostrou dois tipos de associações de espécies de cladóceros fitófilos, caracterizadas pela maior ou menor riqueza e abundância relativa das espécies das famílias Daphniidae e Moinidae (filtradoras, em contraste com as famílias dominantes Chydoridae e Macrothricidae, tipicamente raspadoras do substrato.

  15. Analysis of genetic variation and phylogeny of the predatory bug, Pilophorus typicus, in Japan using mitochondrial gene sequences.

    Science.gov (United States)

    Ito, Katsura; Nishikawa, Hiroshi; Shimada, Takuji; Ogawa, Kohei; Minamiya, Yukio; Tomoda, Masafumi; Nakahira, Kengo; Kodama, Rika; Fukuda, Tatsuya; Arakawa, Ryo

    2011-01-01

    Pilophorus typicus (Distant) (Heteroptera: Miridae) is a predatory bug occurring in East, Southeast, and South Asia. Because the active stages of P. typicus prey on various agricultural pest insects and mites, this species is a candidate insect as an indigenous natural enemy for use in biological control programs. However, the mass releasing of introduced natural enemies into agricultural fields may incur the risk of affecting the genetic integrity of species through hybridization with a local population. To clarify the genetic characteristics of the Japanese populations of P. typicus two portions of the mitochondrial DNA, the cytochrome oxidase subunit I (COI) (534 bp) and the cytochrome B (cytB) (217 bp) genes, were sequenced for 64 individuals collected from 55 localities in a wide range of Japan. Totals of 18 and 10 haplotypes were identified for the COI and cytB sequences, respectively (25 haplotypes over regions). Phylogenetic analysis using the maximum likelihood method revealed the existence of two genetically distinct groups in P. typicus in Japan. These groups were distributed in different geographic ranges: one occurred mainly from the Pacific coastal areas of the Kii Peninsula, the Shikoku Island, and the Ryukyu Islands; whereas the other occurred from the northern Kyushu district to the Kanto and Hokuriku districts of mainland Japan. However, both haplotypes were found in a single locality of the southern coast of the Shikoku Island. COI phylogeny incorporating other Pilophorus species revealed that these groups were only recently differentiated. Therefore, use of a certain population of P. typicus across its distribution range should be done with caution because genetic hybridization may occur.

  16. Response of predatory mites to a herbivore-induced plant volatile: genetic variation for context-dependent behaviour.

    Science.gov (United States)

    Sznajder, Beata; Sabelis, Maurice W; Egas, Martijn

    2010-07-01

    Plants infested with herbivores release specific volatile compounds that are known to recruit natural enemies. The response of natural enemies to these volatiles may be either learned or genetically determined. We asked whether there is genetic variation in the response of the predatory mite Phytoseiulus persimilis to methyl salicylate (MeSa). MeSa is a volatile compound consistently produced by plants being attacked by the two-spotted spider mite, the prey of P. persimilis. We predicted that predators express genetically determined responses during long-distance migration where previously learned associations may have less value. Additionally, we asked whether these responses depend on odors from uninfested plants as a background to MeSa. To infer a genetic basis, we analyzed the variation in response to MeSa among iso-female lines of P. persimilis by using choice-tests that involved either (1) MeSa presented as a single compound or (2) MeSa with background-odor from uninfested lima bean plants. These tests were conducted for starved and satiated predators, i.e., two physiological states, one that approximates migration and another that mimics local patch exploration. We found variation among iso-female lines in the responses to MeSa, thus showing genetic variation for this behavior. The variation was more pronounced in the starved predators, thus indicating that P. persimilis relies on innate preferences when migrating. Background volatiles of uninfested plants changed the predators' responses to MeSa in a manner that depended on physiological state and iso-female line. Thus, it is possible to select for context-dependent behavioral responses of natural enemies to plant volatiles.

  17. Ultrastructure and Pathology of Microsporidium phytoseiuli n. sp. Infecting the Predatory Mite, Phytoseiulus persimilis Athias-Henriot (Acari: Phytoseiidae)

    Science.gov (United States)

    Bjørnson; Steiner; Keddie

    1996-11-01

    Ultrastructure and pathology of Microsporidium phytoseiuli n. sp. infecting the predatory mite Phytoseiulus persimilis Athias-Henriot is described using light and transmission electron microscopy. Infected mites showed no gross, external symptoms. All observed stages of the parasite had unpaired nuclei. Schizonts were commonly observed within nuclei of digestive cells of the ventriculus and within the cytoplasm of cells lining the cecal wall and in muscle tissue underlying it. Sporoblasts and spores occurred in the nuclei and cytoplasm of digestive cells within the ventriculus, in cortical regions of the sub- and supraesophageal ganglia, within the cecal wall and muscle tissue, and in parenchyma cells underlying the cuticle. Mature spores were also observed in developing eggs within gravid females. These were broad- to elongate-ovoid, measured 4.33 ± 0.35 x 1.27 ± 0.15 &mgr;m (electron micrographs), 5.37 ± 0.46 x 2.22 ± 0.17 &mgr;m (fixed and stained), and 5.88 ± 0.34 x 2.22 ± 0.19 &mgr;m (fresh) and had an isolfilar polar filament coiled 12 to 15 times within the posterior two-thirds. Within cells, individual spores appeared to be in direct contact with host cytoplasm, while groups of spores were infrequently observed within interfacial envelopes. Groups of 4, 8, to more than 16 spores were observed by light microscopy, while 8 was the maximum observed by electron microscopy. No spores were observed in Tetranychus urticae, a mite used as food during this study.

  18. Evaluation of various types of supplemental food for two species of predatory mites, Amblyseius swirskii and Neoseiulus cucumeris (Acari: Phytoseiidae).

    Science.gov (United States)

    Delisle, J F; Brodeur, J; Shipp, L

    2015-04-01

    Although phytoseiids are best known as predators of phytophagous mites and other small arthropods, several species can also feed and reproduce on pollen. In laboratory assays, we assessed the profitability of two types of dietary supplements (three pollen species-cattail, maize and apple-and eggs of the Mediterranean flour moth, Ephestia kuehniella) for the two species of predatory mites most commonly used as biocontrol agents in horticulture in Canada, Neoseiulus cucumeris and Amblyseius swirskii. We measured the effects of each diet on phytoseiid fitness parameters (survival, development, sex ratio, fecundity) and, as a means of comparison, when fed larvae of the common targeted pest species, western flower thrips Frankliniella occidentalis. A soluble protein assay was also performed on the alternative food sources as protein content is often linked to high nutritive value according to the literature. All food sources tested were suitable for N. cucumeris and A. swirskii, both species being able to develop from egg to adult. The dietary supplements had a beneficial impact on biological parameters, mostly resulting in shorter development times and higher survival rates when compared to thrips larvae. Amblyseius swirskii exhibited a wider dietary range than N. cucumeris. Overall, flour moth eggs, cattail pollen and apple pollen are food sources of equal quality for A. swirskii, whereas apple and cattail pollen are better when it comes to N. cucumeris. In contrast, maize pollen is a less suitable food source for N. cucumeris and A. swirskii. Soluble protein content results did not match the prediction under which the most beneficial food source would contain the highest concentration in protein.

  19. Predatory functional morphology in raptors: interdigital variation in talon size is related to prey restraint and immobilisation technique.

    Science.gov (United States)

    Fowler, Denver W; Freedman, Elizabeth A; Scannella, John B

    2009-11-25

    Despite the ubiquity of raptors in terrestrial ecosystems, many aspects of their predatory behaviour remain poorly understood. Surprisingly little is known about the morphology of raptor talons and how they are employed during feeding behaviour. Talon size variation among digits can be used to distinguish families of raptors and is related to different techniques of prey restraint and immobilisation. The hypertrophied talons on digits (D) I and II in Accipitridae have evolved primarily to restrain large struggling prey while they are immobilised by dismemberment. Falconidae have only modest talons on each digit and only slightly enlarged D-I and II. For immobilisation, Falconini rely more strongly on strike impact and breaking the necks of their prey, having evolved a 'tooth' on the beak to aid in doing so. Pandionidae have enlarged, highly recurved talons on each digit, an adaptation for piscivory, convergently seen to a lesser extent in fishing eagles. Strigiformes bear enlarged talons with comparatively low curvature on each digit, part of a suite of adaptations to increase constriction efficiency by maximising grip strength, indicative of specialisation on small prey. Restraint and immobilisation strategy change as prey increase in size. Small prey are restrained by containment within the foot and immobilised by constriction and beak attacks. Large prey are restrained by pinning under the bodyweight of the raptor, maintaining grip with the talons, and immobilised by dismemberment (Accipitridae), or severing the spinal cord (Falconini). Within all raptors, physical attributes of the feet trade off against each other to attain great strength, but it is the variable means by which this is achieved that distinguishes them ecologically. Our findings show that interdigital talon morphology varies consistently among raptor families, and that this is directly correlative with variation in their typical prey capture and restraint strategy.

  20. Microplastics have a more profound impact than elevated temperatures on the predatory performance, digestion and energy metabolism of an Amazonian cichlid.

    Science.gov (United States)

    Wen, Bin; Zhang, Nan; Jin, Shi-Rong; Chen, Zai-Zhong; Gao, Jian-Zhong; Liu, Ying; Liu, Han-Peng; Xu, Zhe

    2018-02-01

    Knowledge on the impacts of microplastics (MPs) pollution on freshwater environments and biota remains limited. Meanwhile, freshwater ecosystems have been threatened by elevated temperatures caused by climate change. To date, no information exists on how MPs-especially under elevated temperature conditions-affect predatory performance, digestive processes and metabolic pathways in freshwater organisms. Here, we examined MPs, elevated temperature and their combined effects on juveniles (0+ group) of an Amazonian cichlid, the discus fish (Symphysodon aequifasciatus). For 30 days, fish were exposed to ambient or elevated temperatures (i.e., 28 or 31 °C) in the absence or presence of MPs (i.e., 0 or 200 μg/L). The following metrics were quantified: MPs accumulation; predatory performance; and biomarkers involved in neurotransmission, digestion and energy production. The results showed that survival rate and body length were not affected by MPs, elevated temperatures or their combination. Elevated temperatures resulted in an increase in MP concentrations in fish bodies. Exposure to MPs decreased the post-exposure predatory performance (PEPP) at ambient temperatures but not at elevated temperatures. Elevated temperatures, however, had no effect on the PEPP but antagonistically interacted with MPs, leading to similar predatory performances under present and future conditions. Acetylcholinesterase (AChE) activity was only affected by MPs and decreased in the presence of MPs, indicating adverse effects in nervous and neuromuscular function and, thus, potentially in predatory performance. Trypsin activity was only influenced by MPs and decreased during exposure to MPs. Elevated temperatures or MPs alone increased the amylase activity but interacted antagonistically. Lipase activity was not influenced by either of the two stressors. In contrast, alkaline phosphatase (ALP) activity was affected by MPs or elevated temperatures alone and decreased with both stressors

  1. Novel bacterial pathogen Acaricomes phytoseiuli causes severe disease symptoms and histopathological changes in the predatory mite Phytoseiulus persimilis (Acari, Phytoseiidae).

    Science.gov (United States)

    Schütte, Conny; Gols, Rieta; Kleespies, Regina G; Poitevin, Olivier; Dicke, Marcel

    2008-06-01

    were not observed in control predators that were exposed to sterile water. The present data prove that A. phytoseiuli can infect the predatory mite P. persimilis and induce the NR-syndrome and characteristic histopathological changes in adult female P. persimilis. This is the first record of a bacterial pathogen in a phytoseiid mite and the first description of pathogenic effects of a bacterial species in the genus Acaricomes.

  2. Whole genome amplification of Chelex-extracted DNA from a single mite: a method for studying genetics of the predatory mite Phytoseiulus persimilis.

    Science.gov (United States)

    Konakandla, Bhanu; Park, Yoonseong; Margolies, David

    2006-01-01

    We developed and optimized a method using Chelex DNA extraction followed by whole genome amplification (WGA) to overcome problems conducting molecular genetic studies due to the limited amount of DNA obtainable from individual small organisms such as predatory mites. The DNA from a single mite, Phytoseiulus persimilis Athias-Henrot (Acari: Phytoseiidae), isolated in Chelex suspension was subjected to WGA. More than 1000-fold amplification of the DNA was achieved using as little as 0.03 ng genomic DNA template. The DNA obtained by the WGA was used for polymerase chain reaction followed by direct sequencing. From WGA DNA, nuclear DNA intergenic spacers ITS1 and ITS2 and a mitochondrial DNA 12S marker were tested in three different geographical populations of the predatory mite: California, the Netherlands, and Sicily. We found a total of four different alleles of the 12S in the Sicilian population, but no polymorphism was identified in the ITS marker. The combination of Chelex DNA extraction and WGA is thus shown to be a simple and robust technique for examining molecular markers for multiple loci by using individual mites. We conclude that the methods, Chelex extraction of DNA followed by WGA, provide a large quantity of DNA template that can be used for multiple PCR reactions useful for genetic studies requiring the genotypes of individual mites.

  3. An Entomopathogenic Strain of Beauveria bassiana against Frankliniella occidentalis with no Detrimental Effect on the Predatory Mite Neoseiulus barkeri: Evidence from Laboratory Bioassay and Scanning Electron Microscopic Observation

    Science.gov (United States)

    Wu, Shengyong; Gao, Yulin; Zhang, Yaping; Wang, Endong; Xu, Xuenong; Lei, Zhongren

    2014-01-01

    Among 28 isolates of Beauveria bassiana tested for virulence against F. occidentalis in laboratory bioassays, we found strain SZ-26 as the most potent, causing 96% mortality in adults at 1×107 mL−1conidia after 4 days. The effect of the strain SZ-26 on survival, longevity and fecundity of the predatory mite Neoseiulus (Amblyseius) barkeri Hughes were studied under laboratory conditions. The bioassay results showed that the corrected mortalities were less than 4 and 8% at 10 days following inoculation of the adult and the larvae of the predator, respectively, with 1×107 conidia mL−1 of SZ-26. Furthermore, no fungal hyphae were found in dead predators. The oviposition and postoviposition durations, longevity, and fecundity displayed no significant differences after inoculation with SZ-26 using first-instar larvae of F. occidentalis as prey in comparison with untreated predator. In contrast, the preoviposition durations were significantly longer. Observations with a scanning electron microscope, revealed that many conidia were attached to the cuticles of F. occidentalis at 2 h after treatment with germ tubes oriented toward cuticle at 24 h, penetration of the insect cuticle at 36 h, and finally, fungal colonization of the whole insect body at 60 h. In contrast, we never observed penetration of the predator's cuticle and conidia were shed gradually from the body, further demonstrating that B. bassiana strain SZ-26 show high toxicity against F. occidentalis but no pathogenicity to predatory mite. PMID:24454744

  4. Brominated flame retardants and organochlorine pollutants in aquatic and terrestrial predatory birds of Belgium: levels, patterns, tissue distribution and condition factors

    International Nuclear Information System (INIS)

    Jaspers, V.L.B.; Covaci, A.; Voorspoels, S.; Dauwe, T.; Eens, M.; Schepens, P.

    2006-01-01

    Liver and muscle samples from 7 species of aquatic and terrestrial predatory birds from Flanders (Belgium) were analysed for polychlorinated biphenyls (PCBs), polybrominated diphenylethers (PBDEs) and organochlorine pesticides (OCPs). PCBs were the predominant compounds in our samples, which showed highest concentrations in the liver of barn owl (Tyto alba) and sparrowhawk (Accipiter nisus) (up to 1000 μg/g lipid weight). PBDEs could be determined in most samples at lower concentrations than PCBs (up to 64 μg/g lipid in sparrowhawk liver). Sparrowhawks had the highest levels of hexachlorobenzene, DDTs and PBDEs. In contrast, kestrels (Falco tinnunculus) had relatively low levels of most measured organochlorines. BDE 47 was the most abundant congener in heron (Ardea cinerea) and grebe (Podiceps cristatus), while BDE 47, 99 and 153 were equally important in the terrestrial species. BDE 183 and BDE 209 were only measured in the terrestrial birds. These results indicate that terrestrial birds may be more exposed to higher brominated BDE congeners than aquatic species. - Aquatic and terrestrial predatory birds show different accumulation profiles of PBDEs

  5. An entomopathogenic strain of Beauveria bassiana against Frankliniella occidentalis with no detrimental effect on the predatory mite Neoseiulus barkeri: evidence from laboratory bioassay and scanning electron microscopic observation.

    Directory of Open Access Journals (Sweden)

    Shengyong Wu

    Full Text Available Among 28 isolates of Beauveria bassiana tested for virulence against F. occidentalis in laboratory bioassays, we found strain SZ-26 as the most potent, causing 96% mortality in adults at 1×10(7 mL(-1conidia after 4 days. The effect of the strain SZ-26 on survival, longevity and fecundity of the predatory mite Neoseiulus (Amblyseius barkeri Hughes were studied under laboratory conditions. The bioassay results showed that the corrected mortalities were less than 4 and 8% at 10 days following inoculation of the adult and the larvae of the predator, respectively, with 1×10(7 conidia mL(-1 of SZ-26. Furthermore, no fungal hyphae were found in dead predators. The oviposition and postoviposition durations, longevity, and fecundity displayed no significant differences after inoculation with SZ-26 using first-instar larvae of F. occidentalis as prey in comparison with untreated predator. In contrast, the preoviposition durations were significantly longer. Observations with a scanning electron microscope, revealed that many conidia were attached to the cuticles of F. occidentalis at 2 h after treatment with germ tubes oriented toward cuticle at 24 h, penetration of the insect cuticle at 36 h, and finally, fungal colonization of the whole insect body at 60 h. In contrast, we never observed penetration of the predator's cuticle and conidia were shed gradually from the body, further demonstrating that B. bassiana strain SZ-26 show high toxicity against F. occidentalis but no pathogenicity to predatory mite.

  6. Below-ground plant parts emit herbivore-induced volatiles: olfactory responses of a predatory mite to tulip bulbs infested by rust mites.

    Science.gov (United States)

    Aratchige, N S; Lesna, I; Sabelis, M W

    2004-01-01

    Although odour-mediated interactions among plants, spider mites and predatory mites have been extensively studied above-ground, belowground studies are in their infancy. In this paper, we investigate whether feeding by rust mites (Aceria tulipae) cause tulip bulbs to produce odours that attract predatory mites (Neoseiulus cucumeris). Since our aim was to demonstrate such odours and not their relevance under soil conditions, the experiments were carried out using a classic Y-tube olfactometer in which the predators moved on a Y-shaped wire in open air. We found that food-deprived female predators can discriminate between odours from infested bulbs and odours from uninfested bulbs or artificially wounded bulbs. No significant difference in attractiveness to predators was found between clean bulbs and bulbs either wounded 30 min or 3 h before the experiment. These results indicate that it may not be simply the wounding of the bulbs, but rather the feeding by rust mites, which causes the bulb to release odours that attract N. cucumeris. Since bulbs are belowground plant structures, the olfactometer results demonstrate the potential for odour-mediated interactions in the soil. However, their importance in the actual soil medium remains to be demonstrated.

  7. Predatory behavior of long-legged flies (Diptera:Dolichopodidae) and their potential negative effects on the parasitoid biological control agent of the Asian citrus psyllid (Hemiptera:Liviidae)

    Science.gov (United States)

    Impact of biological control agents such as parasitoids can be improved by determining best times for release when predation pressures will be reduced. Large populations of long-legged predatory flies (Diptera: Dolichopodidae) impose heavy predation pressure on inundative releases of the parasitoid ...

  8. Interactions between natural enemies: Effect of a predatory mite on transmission of the fungus Neozygites floridana in two-spotted spider mite populations.

    Science.gov (United States)

    Trandem, Nina; Berdinesen, Ronny; Pell, Judith K; Klingen, Ingeborg

    2016-02-01

    Introducing the predatory mite Phytoseiulus persimilis into two-spotted spider mite, Tetranychus urticae, populations significantly increased the proportion of T. urticae infected with the spider mite pathogen Neozygites floridana in one of two experiments. By the final sampling occasion, the number of T. urticae in the treatment with both the predator and the pathogen had declined to zero in both experiments, while in the fungus-only treatment T. urticae populations still persisted (20-40 T. urticae/subsample). Releasing P. persimilis into crops in which N. floridana is naturally present has the potential to improve spider mite control more than through predation alone. Copyright © 2016 Elsevier Inc. All rights reserved.

  9. Relationships between Plant Diversity and the Abundance and α-Diversity of Predatory Ground Beetles (Coleoptera: Carabidae) in a Mature Asian Temperate Forest Ecosystem

    Science.gov (United States)

    Zou, Yi; Sang, Weiguo; Bai, Fan; Axmacher, Jan Christoph

    2013-01-01

    A positive relationship between plant diversity and both abundance and diversity of predatory arthropods is postulated by the Enemies Hypothesis, a central ecological top-down control hypothesis. It has been supported by experimental studies and investigations of agricultural and grassland ecosystems, while evidence from more complex mature forest ecosystems is limited. Our study was conducted on Changbai Mountain in one of the last remaining large pristine temperate forest environments in China. We used predatory ground beetles (Coleoptera: Carabidae) as target taxon to establish the relationship between phytodiversity and their activity abundance and diversity. Results showed that elevation was the only variable included in both models predicting carabid activity abundance and α-diversity. Shrub diversity was negatively and herb diversity positively correlated with beetle abundance, while shrub diversity was positively correlated with beetle α-diversity. Within the different forest types, a negative relationship between plant diversity and carabid activity abundance was observed, which stands in direct contrast to the Enemies Hypothesis. Furthermore, plant species density did not predict carabid α-diversity. In addition, the density of herbs, which is commonly believed to influence carabid movement, had little impact on the beetle activity abundance recorded on Changbai Mountain. Our study indicates that in a relatively large and heterogeneous mature forest area, relationships between plant and carabid diversity are driven by variations in environmental factors linked with altitudinal change. In addition, traditional top-down control theories that are suitable in explaining diversity patterns in ecosystems of low diversity appear to play a much less pronounced role in highly complex forest ecosystems. PMID:24376582

  10. Relationships between plant diversity and the abundance and α-diversity of predatory ground beetles (Coleoptera: Carabidae) in a mature Asian temperate forest ecosystem.

    Science.gov (United States)

    Zou, Yi; Sang, Weiguo; Bai, Fan; Axmacher, Jan Christoph

    2013-01-01

    A positive relationship between plant diversity and both abundance and diversity of predatory arthropods is postulated by the Enemies Hypothesis, a central ecological top-down control hypothesis. It has been supported by experimental studies and investigations of agricultural and grassland ecosystems, while evidence from more complex mature forest ecosystems is limited. Our study was conducted on Changbai Mountain in one of the last remaining large pristine temperate forest environments in China. We used predatory ground beetles (Coleoptera: Carabidae) as target taxon to establish the relationship between phytodiversity and their activity abundance and diversity. Results showed that elevation was the only variable included in both models predicting carabid activity abundance and α-diversity. Shrub diversity was negatively and herb diversity positively correlated with beetle abundance, while shrub diversity was positively correlated with beetle α-diversity. Within the different forest types, a negative relationship between plant diversity and carabid activity abundance was observed, which stands in direct contrast to the Enemies Hypothesis. Furthermore, plant species density did not predict carabid α-diversity. In addition, the density of herbs, which is commonly believed to influence carabid movement, had little impact on the beetle activity abundance recorded on Changbai Mountain. Our study indicates that in a relatively large and heterogeneous mature forest area, relationships between plant and carabid diversity are driven by variations in environmental factors linked with altitudinal change. In addition, traditional top-down control theories that are suitable in explaining diversity patterns in ecosystems of low diversity appear to play a much less pronounced role in highly complex forest ecosystems.

  11. Relationships between plant diversity and the abundance and α-diversity of predatory ground beetles (Coleoptera: Carabidae in a mature Asian temperate forest ecosystem.

    Directory of Open Access Journals (Sweden)

    Yi Zou

    Full Text Available A positive relationship between plant diversity and both abundance and diversity of predatory arthropods is postulated by the Enemies Hypothesis, a central ecological top-down control hypothesis. It has been supported by experimental studies and investigations of agricultural and grassland ecosystems, while evidence from more complex mature forest ecosystems is limited. Our study was conducted on Changbai Mountain in one of the last remaining large pristine temperate forest environments in China. We used predatory ground beetles (Coleoptera: Carabidae as target taxon to establish the relationship between phytodiversity and their activity abundance and diversity. Results showed that elevation was the only variable included in both models predicting carabid activity abundance and α-diversity. Shrub diversity was negatively and herb diversity positively correlated with beetle abundance, while shrub diversity was positively correlated with beetle α-diversity. Within the different forest types, a negative relationship between plant diversity and carabid activity abundance was observed, which stands in direct contrast to the Enemies Hypothesis. Furthermore, plant species density did not predict carabid α-diversity. In addition, the density of herbs, which is commonly believed to influence carabid movement, had little impact on the beetle activity abundance recorded on Changbai Mountain. Our study indicates that in a relatively large and heterogeneous mature forest area, relationships between plant and carabid diversity are driven by variations in environmental factors linked with altitudinal change. In addition, traditional top-down control theories that are suitable in explaining diversity patterns in ecosystems of low diversity appear to play a much less pronounced role in highly complex forest ecosystems.

  12. Interactions among the Predatory Midge Aphidoletes aphidimyza (Diptera: Cecidomyiidae, the Fungal Pathogen Metarhizium brunneum (Ascomycota: Hypocreales, and Maize-Infesting Aphids in Greenhouse Mesocosms

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    Ana Gorete Campos de Azevedo

    2017-04-01

    Full Text Available The generalist entomopathogenic fungus, Metarhizium brunneum, has proved to have great potential as a versatile biological pest control agent. The gall midge Aphidoletes aphidimyza is a specialist predator that occurs naturally in Europe and has been successfully used for aphid suppression. However, the interaction between these two biological control organisms and how it may affect the biological control of aphids awaits further investigation. As part of the EU-supported project INBIOSOIL, this study was conducted in greenhouse conditions to assess the possible effects of combining both biological control agents. In a randomized complete block design, sweet corn (Zea mays var. saccharata plants were grown in large pots filled with natural soil or natural soil inoculated with M. brunneum. At the third leaf stage, before being individually caged, plants were infested with Rhopalosiphum padi and A. aphidimyza pupae were introduced in the soil. Aphidoletes aphidimyza midge emergence, number of living midges and number of aphids were recorded daily. The presence of conidia in the soil and on leaves was assessed during the experiment. At the conclusion of the experiment, the number of live aphids and their developmental stage, consumed aphids, and A. aphidimyza eggs was assessed under stereomicroscope. This study’s findings showed that the presence of M. brunneum did not affect A. aphidimyza midge emergence. However, longevity was significantly affected. As the study progressed, significantly fewer predatory midges were found in cages treated with M. brunneum compared to untreated cages. Furthermore, by the end of the study, the number of predatory midges found in the Metarhizium-treated cages was four times lower than in the untreated cages. Both daily and final count of aphids were significantly affected by treatment. Aphidoletes aphidimyza applied alone suppressed the aphid population more effectively than M. brunneum applied alone. Additionally

  13. CONFIRMATION OF PRESENCE OF A PREDATORY GALL MIDGE, Feltiella acarisuga, (Vallot, 1827 AND STAPHYLINID PREDATOR Oligota oviformis Casey, 1893 OF A TWO SPOTTED SPIDER MITE (Tetranychus urticae, Koch, 1836 IN SLOVENIA

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    Katarina KOS

    2018-04-01

    Full Text Available The two spotted spider mite, Tetranychus urticae C. L. Koch, 1836 is one of the most important pests of greenhouse crops worldwide. Due to its polyphagic range of hosts and rapid development it forms great populations and as such represents a suitable host/prey for lots of natural enemies usable in biological control. Most commonly used predators of Tetranychid mites are predatory mites (Phytoseiulus persimilis Athias-Henriot, 1957, Amblyseius swirskii Athias-Henriot, 1962 ,…, but among most voracious predators is the larva of a predatory gall midge, Feltiella acarisuga (Vallot, 1827 that was found also in greenhouses of the Biotechnical Faculty in Ljubljana on eggplant leaves in 2017. Besides the predatory gall midge also another predator, staphylinid Oligota oviformis Casey, 1893 beetles and larvae were found in great numbers. After positive identification of F. acarisuga found naturally in Slovenia, it can be added to the list of indigenous species of natural enemies and thus can be used in biological control programs in greenhouse crop protection against spider mites.

  14. APONTAMENTOS PRELIMINARES SOBRE O USO PREDATÓRIO DA JURISDIÇÃO / PRELIMINARY NOTES ABOUT THE PREDATORY USE OF THE JUDICIARY

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    Maximiliano Losso Bunn

    2016-04-01

    Full Text Available The main goal of this text is to propose a concept for Predatory Use of Judiciary (as a type of contempt of court category and also to present preliminary discussion themes about this phenomenon, considering the high rates of litigation of large corporations in Brazil. The reason to address this issue stems from the recent finding by technical studies that a considerable portion of the sheer number of claims pending in the Brazilian judicial system can be attributed to a small number of large litigants, which consumes considerable percentage of available resources for investment in the administration of justice. Hence, the main hypothesis under discussion relates to the characterization of this phenomenon in the Brazilian scenario, considering the procedural mechanisms related to the repression of bad litigation and the promotion of reconciliation. Secondary hypotheses concern the deleterious effects specifically arising from such phenomenon in the judicial activity, particularly regarding the speed of the trials. The doctrinaire base employed concerns mostly the technical studies which have only recently diagnosed the said phenomenon, so that this text is one of the few preliminary discussions regarding this subject. As for the methodology, it is emphasized that on the investigation phase we used the inductive method, in the data processing phase we used the cartesian method, and the final text was composed in the deductive logic base. In the various stages of the research, we used the technics of category, operational concept and literature research.

  15. Sublethal effects of diazinon, fenitrothion and chlorpyrifos on the functional response of predatory bug, Andrallus spinidens Fabricius (Hem.: Pentatomidae in the laboratory conditions

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    Moloud GholamzadehChitgar

    2014-04-01

    Full Text Available The sublethal effects of diazinon, fenitrothion and chlorpyrifos on the functional response of predatory bug, Andrallus spinidens Fabricius (Hem.: Pentatomidae, a potential biological control agent, were studied on 5th-instar nymphs. The experiment was conducted in varying densities (2, 4, 8, 16, 32 and 64 of last instars larvae of Chilo suppressalis Walker (Lepidoptera: Pyralidae as prey at 25 ± 2 °C, 60% ± 10% relative humidity (RH and a photoperiod of 16:8 h (L: D. The results of logistic regressions revealed a type II functional response in the control and all insecticide treatments. Comparison of functional response curves revealed that tested insecticides markedly decreased the mean of preys consumed by A. spinidens. Among them, functional response curve of A. spinidens in chlorpyrifos treatment was significantly lower than the other treatments. In this study, application of insecticides caused a decrease in the attack rate and an increase in the handling time of exposed bugs compared with the control. The longest handling time (3.97 ± 0.62 and the lowest attack rate (0.023 ± 0.007 were observed in chlorpyrifos and fenitrothion treatments, respectively. The results suggested that the adverse effect of these insecticides on A. spinidens should be considered in integrated pest management programs (IPM.

  16. Maximum swimming speeds of sailfish and three other large marine predatory fish species based on muscle contraction time and stride length: a myth revisited

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    Morten B. S. Svendsen

    2016-10-01

    Full Text Available Billfishes are considered to be among the fastest swimmers in the oceans. Previous studies have estimated maximum speed of sailfish and black marlin at around 35 m s−1 but theoretical work on cavitation predicts that such extreme speed is unlikely. Here we investigated maximum speed of sailfish, and three other large marine pelagic predatory fish species, by measuring the twitch contraction time of anaerobic swimming muscle. The highest estimated maximum swimming speeds were found in sailfish (8.3±1.4 m s−1, followed by barracuda (6.2±1.0 m s−1, little tunny (5.6±0.2 m s−1 and dorado (4.0±0.9 m s−1; although size-corrected performance was highest in little tunny and lowest in sailfish. Contrary to previously reported estimates, our results suggest that sailfish are incapable of exceeding swimming speeds of 10-15 m s−1, which corresponds to the speed at which cavitation is predicted to occur, with destructive consequences for fin tissues.

  17. Predatory ability of Arthrobotrys musiformis and Monacrosporium thaumasium on Scutellonema bradys Capacidade predatória de Arthrobotrys musiformis e Monacrosporium thaumasium a Scutellonema bradys

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    Ana Cristina Fermino Soares

    2006-08-01

    Full Text Available Scutellonema bradys (Steiner & LeHew Andrassy is the most important yam nematode in the State of Bahia, Brazil, being responsible for the decay of yam tubers, known as dry rot disease. Nematode-trapping fungi are potential biocontrol agents against plant parasitic nematodes. The in vitro predatory ability of Arthrobotrys musiformis Drechsler and Monacrosporium thaumasium Drechsler on S. bradys was evaluated. The fungi were grown in PDA medium, than transferred to the center of Petri dishes with 2% agar plus water. After 14 days of the fungal cultures incubation, 150 nematodes were added to the dishes. For a period of 5 days, at 24-hour intervals, the number of captured nematodes was counted. Both fungi formed trapping structures of single ring and three-dimensional adhesive network types, 24 hours after the addition of the nematodes to the fungal cultures. The percentage of nematodes captured by each fungus increased linearly with time, reaching 94.6% and 97.3% of captured nematodes by A. musiformis and M. thaumasium, respectively, at the fifth day of evaluation. Both fungi presented good predatory ability upon S. bradys. This is the first report of nematophagous fungi capturing S. bradys. Further studies should evaluate the potential of these fungi as biocontrol agents of S. bradys in yam plantations.Scutellonema bradys (Steiner & LeHew Andrassy é o nematóide mais importante da cultura do inhame (Dioscorea cayennensis Lam. no Estado da Bahia, Brasil, responsável pela necrose superficial das túberas, conhecida como casca preta do inhame. Os fungos nematófagos são potenciais agentes de biocontrole contra nematóides fitoparasitos. A atividade predatória de Arthrobotrys musiformis Drechsler a S. bradys foi avaliada in vitro. Os fungos foram multiplicados em meio BDA durante 15 dias, transferidos para o centro de placas de Petri contendo 2% de agar-água e após 14 dias de incubação, foram adicionados 150 nematóides. Durante cinco dias

  18. Capacidade Predatória de Euborellia annulipes (Lucas, 1847 sobre Spodoptera frugiperda (Smith, 1797 = Predatory Capacity of Euborellia annulipes (Lucas, 1847 on Spodoptera frugiperda (Smith, 1797

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    Aldeni Barbosa da Silva

    2009-01-01

    Full Text Available Estudou-se a Capacidade Predatória de Euborellia annulipes sobre Spodoptera frugiperda em laboratório. O estudo foi conduzido no Laboratório de Entomologia do Setor de Fitossanidade da Universidade Federal da Paraíba (UFPB à temperatura de 25 ± 1ºC, umidade relativa de 70 + 10% e fotofase de 12h. Notou-se consumo crescente de ovos,podendo ser observado consumo diário médio de 11,06, 49,02, 122,7, 148,09 e 374,9 ovos, do 1° ao 5° instar, respectivamente. A capacidade predatória sobre lagartas de 1° instar de S. frugiperda aumentou de acordo com o seu desenvolvimento, com aumento de,aproximadamente, 14,3 vezes do 1° ao 5° instar, nos dez dias de consumo, sendo que, o 4° e o 5° instares apresentaram consumo diário médio de 25,5 e 26,6, respectivamente, bem superior em comparação aos demais instares; o maior consumo de lagartas de 2º instar pelopredador, ocorreu no 4º e 5º instar, que apresentaram consumo diário médio de 12,8 e 15,1, respectivamente. Verifica-se que E. annulipes demonstra ser predador potencial de ovos e lagartas de S. frugiperda, chegando um adulto a consumir 1.481,2; 89,20 e 48,6 ovos e lagartasde 1º e 2º instares, respectivamente, nos dez dias de consumo.The predatory capacity of Euborellia annulipes on Spodopterafrugiperda was studied in a laboratory setting. The study was conducted in the Laboratory of Entomology of the Division of Plant Protection, Federal University of Paraíba (UFPB at a temperature of 25 ± 1°C, relative humidity of 70 + 10% and a 12-hour photophase. Thestudy detected growing egg intake, with an average daily consumption of 11.06, 49.02, 122.7, 148.09 and 374.9 eggs, from the first to the fifth instars, respectively. A predatory capacity of fist-instar larvae of S. frugiperda increased in line with its development, with an increase of approximately 14.3 times from the first to the fifth instar, in the 10 days of consumption, whereas the fourth and fifth instars presented an

  19. Integrated pest management of two-spotted mite Tetranychus urticae on greenhouse roses using petroleum spray oil and the predatory mite Phytoseiulus persimilis.

    Science.gov (United States)

    Nicetic; Watson, D M; Beattie, G A; Meats, A; Zheng, J

    2001-01-01

    From 1995 to 1999, four experiments were conducted on greenhouse roses to assess the effectiveness of the nC24 petroleum spray oil (PSO), D-C-Tron Plus, against two-spotted mite, Tetranychus urticae Koch (Acarina: Tetranychidae), and to determine how the oil could be most efficiently and effectively used in combination with the predatory mite Phytoseiulus persimilis Athias-Henriot (Acarina: Phytoseiidae) in an integrated pest management program. The results showed that 0.5% PSO applied fortnightly to roses gave excellent protection from T urticae infestation when the mite population was not already established. However, PSO applied after roses were infested with T. urticae above the economic threshold only stabilised populations without reducing them below that threshold. Populations of P. persimilis in the upper and lower canopies were unchanged after two sprays of PSO at 7-day intervals, and application of PSO to the upper canopy was as effective in controlling T. urticae in the presence of P persimilis as spraying the entire plant. Combining PSO with P. persimilis gave better control of T. urticae than using P. persimilis alone. The most cost-effective use of PSO in the presence of P. persimilis is, therefore, to apply spray only to the upper canopy. This will not affect control of powdery mildew with PSO. Comparison of a control program for T urticae based on the monitored use of synthetic miticides with that based on calendar application of PSO revealed that both gave equally effective control. The benefits of combining PSO and P. persimilis in an integrated pest management program for T. urticae on roses over a program based on synthetic fungicides are discussed.

  20. From repulsion to attraction: species- and spatial context-dependent threat sensitive response of the spider mite Tetranychus urticae to predatory mite cues

    Science.gov (United States)

    Fernández Ferrari, M. Celeste; Schausberger, Peter

    2013-06-01

    Prey perceiving predation risk commonly change their behavior to avoid predation. However, antipredator strategies are costly. Therefore, according to the threat-sensitive predator avoidance hypothesis, prey should match the intensity of their antipredator behaviors to the degree of threat, which may depend on the predator species and the spatial context. We assessed threat sensitivity of the two-spotted spider mite, Tetranychus urticae, to the cues of three predatory mites, Phytoseiulus persimilis, Neoseiulus californicus, and Amblyseius andersoni, posing different degrees of risk in two spatial contexts. We first conducted a no-choice test measuring oviposition and activity of T. urticae exposed to chemical traces of predators or traces plus predator eggs. Then, we tested the site preference of T. urticae in choice tests, using artificial cages and leaves. In the no-choice test, T. urticae deposited their first egg later in the presence of cues of P. persimilis than of the other two predators and cue absence, indicating interspecific threat-sensitivity. T. urticae laid also fewer eggs in the presence of cues of P. persimilis and A. andersoni than of N. californicus and cue absence. In the artificial cage test, the spider mites preferred the site with predator traces, whereas in the leaf test, they preferentially resided on leaves without traces. We argue that in a nonplant environment, chemical predator traces do not indicate a risk for T. urticae, and instead, these traces function as indirect habitat cues. The spider mites were attracted to these cues because they associated them with the existence of a nearby host plant.

  1. Social familiarity governs prey patch-exploitation, -leaving and inter-patch distribution of the group-living predatory mite Phytoseiulus persimilis.

    Science.gov (United States)

    Zach, Gernot J; Peneder, Stefan; Strodl, Markus A; Schausberger, Peter

    2012-01-01

    In group-living animals, social interactions and their effects on other life activities such as foraging are commonly determined by discrimination among group members. Accordingly, many group-living species evolved sophisticated social recognition abilities such as the ability to recognize familiar individuals, i.e. individuals encountered before. Social familiarity may affect within-group interactions and between-group movements. In environments with patchily distributed prey, group-living predators must repeatedly decide whether to stay with the group in a given prey patch or to leave and search for new prey patches and groups. Based on the assumption that in group-living animals social familiarity allows to optimize the performance in other tasks, as for example predicted by limited attention theory, we assessed the influence of social familiarity on prey patch exploitation, patch-leaving, and inter-patch distribution of the group-living, plant-inhabiting predatory mite Phytoseiulus persimilis. P. persimilis is highly specialized on herbivorous spider mite prey such as the two-spotted spider mite Tetranychus urticae, which is patchily distributed on its host plants. We conducted two experiments with (1) groups of juvenile P. persimilis under limited food on interconnected detached leaflets, and (2) groups of adult P. persimilis females under limited food on whole plants. Familiar individuals of both juvenile and adult predator groups were more exploratory and dispersed earlier from a given spider mite patch, occupied more leaves and depleted prey more quickly than individuals of unfamiliar groups. Moreover, familiar juvenile predators had higher survival chances than unfamiliar juveniles. We argue that patch-exploitation and -leaving, and inter-patch dispersion were more favorably coordinated in groups of familiar than unfamiliar predators, alleviating intraspecific competition and improving prey utilization and suppression.

  2. Total effects of contact and residual exposure of bifenthrin and λ-cyhalothrin on the predatory mite Galendromus occidentalis (Acari: Phytoseiidae).

    Science.gov (United States)

    Hamby, Kelly A; Alifano, Jesse A; Zalom, Frank G

    2013-10-01

    Pyrethroid insecticides are generally regarded as acutely toxic to predatory phytoseiid mites; however, persistence of hull split spray pyrethroid residues on almond trees and their effects on phytoseiids have not been quantified over time. Hull split, the separation of the almond hull along the suture, exposes the new crop nuts to infestation by Amyelois transitella (Walker) larvae, and is the preferred timing for insecticides applied for their control. Galendromus occidentalis (Nesbitt) is the most important phytoseiid biocontrol agent for web-spinning spider mites in California (USA) almond orchards, and the impact of bifenthrin and λ-cyhalothrin pyrethroid residue on their survival, fertility, and fecundity was determined. The total effects of direct contact with esfenvalerate, permethrin, bifenthrin and λ-cyhalothrin were also evaluated for comparison. The total effects (E) of direct contact treatments of the four pyrethroids ranged from 77.8 % for esfenvalerate to 98.8 % for bifenthrin. Both bifenthrin and λ-cyhalothrin twig residue would be considered harmful (IOBC class 4) following field application at hull split timing. Bifenthrin twig residue would be considered slightly harmful (IOBC class 2) for up to 3.5 months and harmless (IOBC class 1) after 6 months. λ-cyhalothrin residue would be considered moderately harmful (IOBC class 3) for up to 3.5 months following application and harmless (IOBC class 1) after 6 months. Bifenthrin and λ-cyhalothrin twig residue on treated trees significantly reduced G. occidentalis female survival for up to 6 months post-treatment, however total effects (E) classify these residues as harmless (IOBC class 1) after 6 months. Harmful effects of direct and residual exposure following application have implications for the use of these pyrethroids in an integrated mite management program for perennial crops.

  3. Selection of nectar plants for use in ecological engineering to promote biological control of rice pests by the predatory bug, Cyrtorhinus lividipennis, (Heteroptera: Miridae).

    Science.gov (United States)

    Zhu, Pingyang; Lu, Zhongxian; Heong, Kongluen; Chen, Guihua; Zheng, Xusong; Xu, Hongxing; Yang, Yajun; Nicol, Helen I; Gurr, Geoff M

    2014-01-01

    Ecological engineering for pest management involves the identification of optimal forms of botanical diversity to incorporate into a farming system to suppress pests, by promoting their natural enemies. Whilst this approach has been extensively researched in many temperate crop systems, much less has been done for rice. This paper reports the influence of various plant species on the performance of a key natural enemy of rice planthopper pests, the predatory mirid bug, Cyrtorhinus lividipennis. Survival of adult males and females was increased by the presence of flowering Tagetes erecta, Trida procumbens, Emilia sonchifolia (Compositae), and Sesamum indicum (Pedaliaceae) compared with water or nil controls. All flower treatments resulted in increased consumption of brown plant hopper, Nilaparvata lugens, and for female C. lividipennis, S. indicum was the most favorable. A separate study with a wider range of plant species and varying densities of prey eggs showed that S. indicum most strongly promoted predation by C. lividipennis. Reflecting this, S. indicum gave a relatively high rate of prey search and low prey handling time. On this basis, S. indicum was selected for more detailed studies to check if its potential incorporation into the farming system would not inadvertently benefit Cnaphalocrocis medinalis and Marasmia patnalis, serious Lepidoptera pests of rice. Adult longevity and fecundity of both pests was comparable for S. indicum and water treatments and significantly lower than the honey solution treatment. Findings indicate that S. indicumis well suited for use as an ecological engineering plant in the margins of rice crops. Sesame indicum can be a valuable crop as well as providing benefits to C. lividipennis whilst denying benefit to key pests.

  4. Biological aspects and predatory capacity of Podisus nigrispinus (Dallas (Hemiptera: Pentatomidae fed on Alabama argillacea (Hübner (Lepidoptera: Noctuidae reared on cotton genotypes

    Directory of Open Access Journals (Sweden)

    Santos Terezinha Monteiro dos

    2002-01-01

    Full Text Available Host plants may influence indirectly biological characteristics of predators, on a positive or negative way, poiting out the importance of studies evaluating the effect of cultivars on the third trophic level. This study evaluates the biological aspects and predatory capacity of Podisus nigrispinus adults fed Alabama argillacea larvae reared on cotton genotypes. The predator was fed daily with fourth instar larvae reared on leaves of the following genotypes CNPA Precoce 1 (hirsute, CNPA 9211-31 (high gossypol level, CNPA 9211-41 (medium gossypol level and GL2 GL3 (gossypol glandless. The pre-oviposition, oviposition and post-oviposition periods and the oviposition capacity of P. nigripinus were not affected when preyed on cotton leafworms reared on the listed cotton genotypes. Mean weight of predator females was higher (126.2 mg when they fed on A. argillacea reared on GL2 GL3 cotton leaves, in comparison to the observed weight (96.2mg of P. nigripinus females fed on larvae reared on CNPA 9211-41. Longevity of P. nigrispinus ranged 30.7 to 31.5 days for females and 38.0 to 66.3 days for males. P. nigrispinus females preyed 125.2 to 184.0 A. argillacea larvae during its adult stage, while adult males preyed 135.7 to 205.0 leafworms. Using plant resistance in association with P. nigrispinus is viable to control A. argillacea, because resistant genotypes do not influence negatively the biological characteristics of the predator.

  5. Whole-Genome Sequencing and Comparative Genome Analysis Provided Insight into the Predatory Features and Genetic Diversity of Two Bdellovibrio Species Isolated from Soil

    Directory of Open Access Journals (Sweden)

    Omotayo Opemipo Oyedara

    2018-01-01

    Full Text Available Bdellovibrio spp. are predatory bacteria with great potential as antimicrobial agents. Studies have shown that members of the genus Bdellovibrio exhibit peculiar characteristics that influence their ecological adaptations. In this study, whole genomes of two different Bdellovibrio spp. designated SKB1291214 and SSB218315 isolated from soil were sequenced. The core genes shared by all the Bdellovibrio spp. considered for the pangenome analysis including the epibiotic B. exovorus were 795. The number of unique genes identified in Bdellovibrio spp. SKB1291214, SSB218315, W, and B. exovorus JJS was 1343, 113, 857, and 1572, respectively. These unique genes encode hydrolytic, chemotaxis, and transporter proteins which might be useful for predation in the Bdellovibrio strains. Furthermore, the two Bdellovibrio strains exhibited differences based on the % GC content, amino acid identity, and 16S rRNA gene sequence. The 16S rRNA gene sequence of Bdellovibrio sp. SKB1291214 shared 99% identity with that of an uncultured Bdellovibrio sp. clone 12L 106 (a pairwise distance of 0.008 and 95–97% identity (a pairwise distance of 0.043 with that of other culturable terrestrial Bdellovibrio spp., including strain SSB218315. In Bdellovibrio sp. SKB1291214, 174 bp sequence was inserted at the host interaction (hit locus region usually attributed to prey attachment, invasion, and development of host independent Bdellovibrio phenotypes. Also, a gene equivalent to Bd0108 in B. bacteriovorus HD100 was not conserved in Bdellovibrio sp. SKB1291214. The results of this study provided information on the genetic characteristics and diversity of the genus Bdellovibrio that can contribute to their successful applications as a biocontrol agent.

  6. Reducing the impact of pesticides on biological control in Australian vineyards: pesticide mortality and fecundity effects on an indicator species, the predatory mite Euseius victoriensis (Acari: Phytoseiidae).

    Science.gov (United States)

    Bernard, Martina B; Cole, Peter; Kobelt, Amanda; Horne, Paul A; Altmann, James; Wratten, Stephen D; Yen, Alan L

    2010-12-01

    Laboratory bioassays on detached soybean, Glycine max (L.) Merr., leaves were used to test 23 fungicides, five insecticides, two acaricides, one herbicide, and two adjuvants on a key Australian predatory mite species Euseius victoriensis (Womersley) in "worst-case scenario" direct overspray assays. Zero- to 48-h-old juveniles, their initial food, and water supply were sprayed to runoff with a Potter tower; spinosad and wettable sulfur residues also were tested. Tests were standardized to deliver a pesticide dose comparable with commercial application of highest label rates at 1,000 liter/ha. Cumulative mortality was assessed 48 h, 4 d, and 7 d after spraying. Fecundity was assessed for 7 d from start of oviposition. No significant mortality or fecundity effects were detected for the following compounds at single-use application at 1,000 liter/ha: azoxystrobin, Bacillus thuringiensis (Bt) subsp. kurstaki, captan, chlorothalonil, copper hydroxide, fenarimol, glyphosate, hexaconazole, indoxacarb, metalaxyl/copper hydroxide, myclobutanil, nonyl phenol ethylene oxide, phosphorous acid, potassium bicarbonate, pyraclostrobin, quinoxyfen, spiroxamine, synthetic latex, tebufenozide, triadimenol, and trifloxystrobin. Iprodione and penconazole had some detrimental effect on fecundity. Canola oil as acaricide (2 liter/100 liter) and wettable sulfur (200 g/100 liter) had some detrimental effect on survival and fecundity and cyprodinil/fludioxonil on survivor. The following compounds were highly toxic (high 48-h mortality): benomyl, carbendazim, emamectin benzoate, mancozeb, spinosad (direct overspray and residue), wettable sulfur (> or = 400 g/100 liter), and pyrimethanil; pyrimethanil had no significant effect on fecundity of surviving females. Indoxacarb safety to E. victoriensis contrasts with its toxicity to key parasitoids and chrysopid predators. Potential impact of findings is discussed.

  7. Selection of nectar plants for use in ecological engineering to promote biological control of rice pests by the predatory bug, Cyrtorhinus lividipennis, (Heteroptera: Miridae.

    Directory of Open Access Journals (Sweden)

    Pingyang Zhu

    Full Text Available Ecological engineering for pest management involves the identification of optimal forms of botanical diversity to incorporate into a farming system to suppress pests, by promoting their natural enemies. Whilst this approach has been extensively researched in many temperate crop systems, much less has been done for rice. This paper reports the influence of various plant species on the performance of a key natural enemy of rice planthopper pests, the predatory mirid bug, Cyrtorhinus lividipennis. Survival of adult males and females was increased by the presence of flowering Tagetes erecta, Trida procumbens, Emilia sonchifolia (Compositae, and Sesamum indicum (Pedaliaceae compared with water or nil controls. All flower treatments resulted in increased consumption of brown plant hopper, Nilaparvata lugens, and for female C. lividipennis, S. indicum was the most favorable. A separate study with a wider range of plant species and varying densities of prey eggs showed that S. indicum most strongly promoted predation by C. lividipennis. Reflecting this, S. indicum gave a relatively high rate of prey search and low prey handling time. On this basis, S. indicum was selected for more detailed studies to check if its potential incorporation into the farming system would not inadvertently benefit Cnaphalocrocis medinalis and Marasmia patnalis, serious Lepidoptera pests of rice. Adult longevity and fecundity of both pests was comparable for S. indicum and water treatments and significantly lower than the honey solution treatment. Findings indicate that S. indicumis well suited for use as an ecological engineering plant in the margins of rice crops. Sesame indicum can be a valuable crop as well as providing benefits to C. lividipennis whilst denying benefit to key pests.

  8. Effects of deltamethrin, dimethoate, and chlorpyrifos on survival and reproduction of the collembolan Folsomia candida and the predatory mite Hypoaspis aculeifer in two African and two European soils.

    Science.gov (United States)

    Jaabiri Kamoun, Ikram; Jegede, Olukayode O; Owojori, Olugbenga J; Bouzid, Jalel; Gargouri, Radhia; Römbke, Jörg

    2018-01-01

    Indiscriminate use of pesticides is rampant in most parts of Africa, but only scanty ecotoxicological data exist for the protection of soil organisms-and these data were usually obtained under temperate conditions, including the use of Organisation for Economic Co-operation and Development (OECD) standard test protocols. In order to assess the effects of 3 commonly used pesticides (deltamethrin, dimethoate, chlorpyrifos) on soil fauna in Africa, noncontaminated natural soils were collected from Nigeria and Tunisia. In addition, 2 common test soils, OECD artificial soil and European (Landwirtschaftliche Untersichungs- und Forschungsanstalt [LUFA]) 2.3 soil, were used in OECD standard reproduction tests. Two microarthropod species, the springtail Folsomia candida and the predatory mite Hypoaspis aculeifer, were exposed in these 4 soils spiked individually with the 3 insecticides. Results show that the collembolan F. candida was more sensitive than the mite H. aculeifer for all 3 insecticides. The toxicity of each insecticide in the 4 soils differed, with few exceptions, by less than an order of magnitude. However, the pattern of toxicity was not consistent, that is, the lowest toxicity was often but not always found in OECD artificial soil. Soil- and pesticide-specific patterns of toxicity to F. candida and H. aculeifer might be related to the physicochemical properties of the soils and thus the availability of the 3 pesticides. Following the rules laid down in the European Union for the registration of pesticides and using standard European exposure scenarios, neither an acute nor a chronic risk of dimethoate and chlorpyrifos can be excluded (with few exceptions) in all 4 soils. Lower risks were identified for deltamethrin. For pesticide used in Africa, an environmental risk assessment based on data gained in tests with at least 1 additional natural field soil, preferably of African origin, should be performed using the same risk assessment principles as in the

  9. Social familiarity governs prey patch-exploitation, -leaving and inter-patch distribution of the group-living predatory mite Phytoseiulus persimilis.

    Directory of Open Access Journals (Sweden)

    Gernot J Zach

    Full Text Available In group-living animals, social interactions and their effects on other life activities such as foraging are commonly determined by discrimination among group members. Accordingly, many group-living species evolved sophisticated social recognition abilities such as the ability to recognize familiar individuals, i.e. individuals encountered before. Social familiarity may affect within-group interactions and between-group movements. In environments with patchily distributed prey, group-living predators must repeatedly decide whether to stay with the group in a given prey patch or to leave and search for new prey patches and groups.Based on the assumption that in group-living animals social familiarity allows to optimize the performance in other tasks, as for example predicted by limited attention theory, we assessed the influence of social familiarity on prey patch exploitation, patch-leaving, and inter-patch distribution of the group-living, plant-inhabiting predatory mite Phytoseiulus persimilis. P. persimilis is highly specialized on herbivorous spider mite prey such as the two-spotted spider mite Tetranychus urticae, which is patchily distributed on its host plants. We conducted two experiments with (1 groups of juvenile P. persimilis under limited food on interconnected detached leaflets, and (2 groups of adult P. persimilis females under limited food on whole plants. Familiar individuals of both juvenile and adult predator groups were more exploratory and dispersed earlier from a given spider mite patch, occupied more leaves and depleted prey more quickly than individuals of unfamiliar groups. Moreover, familiar juvenile predators had higher survival chances than unfamiliar juveniles.We argue that patch-exploitation and -leaving, and inter-patch dispersion were more favorably coordinated in groups of familiar than unfamiliar predators, alleviating intraspecific competition and improving prey utilization and suppression.

  10. Leptodora kindtii survival in the laboratory

    NARCIS (Netherlands)

    Pichlová, R.; Weber, A.; Gosser, B.

    2004-01-01

    Leptodora kindtii, a pelagic predatory cladoceran, suffers high mortality on transfer to laboratory, which makes the experimental work difficult. We investigated the causes of high mortality, using four variables: water volume, animal density, light intensity, and origin of water for culturing,

  11. Temperature influences the toxicity of deltamethrin, chlorpyrifos and dimethoate to the predatory mite Hypoaspis aculeifer (Acari) and the springtail Folsomia candida (Collembola).

    Science.gov (United States)

    Jegede, O O; Owojori, O J; Römbke, J

    2017-06-01

    In order to assess the influence of temperature on pesticide toxicity to soil fauna, specimens of the predatory mite Hypoaspis aculeifer and the springtail Folsomia candida were exposed in artificial soil spiked with different concentrations of three pesticides (dimethoate, chlorpyrifos and deltamethrin) at 20°C vs 28°C for the mites and 20°C vs 26°C for the springtails. All tests were carried out according to OECD guidelines. In the mite tests, the toxic effects of dimethoate and chlorpyrifos on survival was about two orders of magnitude more at 28°C than at 20°C. Mite reproduction decreased in the tests with chlorpyrifos and deltamethrin by about four to five orders of magnitude at 28°C than at 20°C. (EC50 28 ° C =1.42 and 2.52mg/kg vs EC50 20 ° C =6.18 and 10.09mg/kg) In the collembolan tests, the toxicity of dimethoate on survival was higher at 26°C than at 20°C (LC50 26 ° C =0.17mg/kg vs LC50 20 ° C =0.36mg/kg), while the opposite was detected for deltamethrin (LC50 26 ° C =11.27mg/kg vs LC50 20 ° C =6.84mg/kg). No difference was found in the test with chlorpyrifos. Effects of dimethoate and chlorpyrifos on reproduction were higher at 26°C than at 20°C (EC50 26 ° C =0.11 and 0.018mg/kg vs EC50 20 ° C =0.29 and 0.031mg/kg respectively), but in the case of deltamethrin the opposite was observed (EC50 26 ° C =12.85mg/kg vs EC50 20 ° C =2.77mg/kg). A preliminary risk assessment of the three pesticides at the two temperature regimes based on the Toxicity Exposure Ratio (TER) approach of the European Union, shows that in general there are few different outcomes when comparing data gained at different temperatures. However, in the light of the few comparisons made data gained in temperate regions should be used with caution in the tropics. Copyright © 2017 Elsevier Inc. All rights reserved.

  12. 2014 status of the Lake Ontario lower trophic levels

    Science.gov (United States)

    Holeck, Kristen T.; Rudstam, Lars G.; Hotaling, Christopher; McCullough, Russ D.; Lemon, Dave; Pearsall, Web; Lantry, Jana; Connerton, Michael J.; LaPan, Steve; Biesinger, Zy; Lantry, Brian F.; Walsh, Maureen; Weidel, Brian C.

    2015-01-01

    Soluble reactive phosphorus (SRP) concentrations have been stable in nearshore and offshore habitats since 1998 (0.4 – 3.3 μg/L). SRP concentrations were low in 2014; Apr/May – Oct mean values were Water Quality Agreement of 1978 for offshore waters of Lake Ontario. TP concentrations were low at both nearshore and offshore locations; Apr/May – Oct mean values from individual sites ranged from 4.6 – 9.1 μg/L. Spring TP has declined significantly in the longer data series (since 1981), but not since 1995 indicating stable nutrient loading into Lake Ontario for nearly two decades. It averaged 7.8 μg/L in the nearshore and 5.6 μg/L in the offshore in 2014.Chlorophyll-a and secchi depth values are indicative of oligotrophic conditions in nearshore and offshore habitats. Offshore summer chlorophyll-a declined significantly in both the short- (2000-2014) and long-term (1981-2014) time series at a rate of 4-6% per year. Nearshore chlorophyll-a increased after 2003 but then declined again after 2009. Epilimnetic chlorophyll-a averaged between 0.6 and 1.6 μg/L across sites with no difference between nearshore and offshore habitats. Apr/May – Oct Secchi depth ranged from 4.0 m to 10.8 m at individual sites and was higher in the offshore (average 9.1 m) than nearshore (5.9 m).In 2014, Apr/May – Oct epilimnetic zooplankton density, size, and biomass were not different between the offshore and the nearshore, and there were no differences in epilimnetic biomass between offshore and nearshore areas for any of the zooplankton groups.Zooplankton density and biomass peaked in September, an atypical pattern. This coincided with peaks in calanoid copepod, daphnid, and Holopedium biomass. Holopedium biomass in the nearshore increased significantly since 1995.The predatory cladoceran Cercopagis continued to be abundant in the summer, peaking at ~10 mg/m3in the offshore. Bythotrephes biomass was at its lowest level since 2005 in both offshore and nearshore habitats

  13. Publishing corruption discussion: predatory journalism.

    Science.gov (United States)

    Jones, James W; McCullough, Laurence B

    2014-02-01

    Dr Spock is a brilliant young vascular surgeon who is up for tenure next year. He has been warned by the chair of surgery that he needs to increase his list of publications to assure passage. He has recently had a paper reviewed by one of the top journals in his specialty, Journal X-special, with several suggestions for revision. He received an e-mail request for manuscript submission from a newly minted, open access, Journal of Vascular Disease Therapy, which promises a quick and likely favorable response for a fee. What should be done? A. Send the paper to another peer reviewed journal with the suggested revisions. B. Resubmit the paper to Journal X-special. C. Submit to the online journal as is to save time. D. Submit to the online journal and another regular journal. E. Look for another job. Copyright © 2014 Society for Vascular Surgery. Published by Mosby, Inc. All rights reserved.

  14. Mathematical Modelling of Predatory Prokaryotes

    NARCIS (Netherlands)

    Wilkinson, Michael H.F.

    2006-01-01

    Predator–prey models have a long history in mathematical modelling of ecosystem dynamics and evolution. In this chapter an introduction to the methodology of mathematical modelling is given, with emphasis on microbial predator–prey systems, followed by a description of variants of the basic

  15. Egg dumping by predatory insects

    Czech Academy of Sciences Publication Activity Database

    Corbani, A. C.; Ferrer, A.; Dixon, Anthony F. G.; Hemptinne, J. L.

    2011-01-01

    Roč. 36, č. 3 (2011), s. 290-293 ISSN 0307-6962 Institutional research plan: CEZ:AV0Z60870520 Keywords : Egg dumping * ladybird beetles * oocyte resorption * trophic egg Subject RIV: EH - Ecology, Behaviour Impact factor: 1.330, year: 2011

  16. Human predatory behavior and the social implications of communal hunting based on evidence from the TD10.2 bison bone bed at Gran Dolina (Atapuerca, Spain).

    Science.gov (United States)

    Rodríguez-Hidalgo, Antonio; Saladié, Palmira; Ollé, Andreu; Arsuaga, Juan Luis; Bermúdez de Castro, José María; Carbonell, Eudald

    2017-04-01

    , the results indicate the procurement of bison by communal hunting as early as circa 400 kyr. This suggests that the cognitive, social, and technological capabilities required for successful communal hunting were at least fully developed among the pre-Neanderthal paleodeme of Atapuerca during the Lower Paleolithic. Similarly, the early existence of mass communal hunting as a predation technique informs our understanding of the early emergence of predatory skills similar to those exhibited by modern communal hunters. La zooarqueología es una importante herramienta para la reconstrucción de la subsistencia y también para inferir aspectos relevantes del comportamiento social en el pasado. En este trabajo presentamos el análisis faunístico del llamado "lecho de huesos de bisonte", contenido en la subunidad TD10.2 del yacimiento Gran Dolina (Atapuerca, España). La composición taxonómica y perfil anatómico indican un conjunto monoespecífico fuertemente dominado por elementos del esqueleto axial de bisonte (Bison sp.). Las características y abundancia de las modificaciones antrópicas revelan un acceso primario e inmediato a las carcasas, así como el desarrollo de un procesado carnicero sistemático dirigido a la explotación de la carne y grasa, y a la preparación para el transporte de elementos de alto rendimiento hacia algún lugar fuera de la cavidad. Esas características unidas a un perfil de mortalidad catastrófico y estacional, sugieren la obtención de los bisontes mediante caza comunal. La frecuencia, localización e intensidad de las mordeduras de carnívoro en los restos indica un fuerte saqueo de las carcasas de bisonte una vez abandonadas éstas por los homininos en el yacimiento. La suma de decisiones antrópicas sobre el transporte y el posterior saqueo por carnívoros de los despojos abandonados resulta en un conjunto interpretado como lugar de matanza y procesamiento carnicero de bisontes carroñeados posteriormente por las fieras. Las analog

  17. Sampling necrophagous and predatory insects using different lures in a Mexican pine forest Muestreo de insectos necrófagos y depredadores utilizando diferentes cebos en un bosque de pino en México

    Directory of Open Access Journals (Sweden)

    Gerardo Sánchez-Rojas

    2011-09-01

    Full Text Available Sampling with a single bait as a lure is a commonly used practice in studies of necrophilous insect communities. Here, we determined if there were differences in necrophilous insect species richness and abundance when attracted to 4 types of carrion: squid, bird, lizard, and mouse. A comparison between necrophagous and predatory insects was also made to detect whether they differ in their abundance, depending on the bait used. Thirteen species of Silphidae, Staphylinidae (Coleoptera, Calliphoridae, and Sarcophagidae (Diptera were collected in the baited traps; no single bait was able to attract all species. The abundances of 5 species varied significantly depending on the type of bait used. Predatory insects were less abundant than necrophagous insects in lizard and mouse baits. These results show that an evaluation of the structure of a necrophilous insect community can depend on the bait used for sampling.La utilización de un solo tipo de cebo es una práctica común en los estudios de comunidades de insectos necrófilos. En este trabajo determinamos si existen diferencias en la riqueza y abundancia de especies de insectos necrófilos atraídos a 4 tipos de carroña: calamar, ave, lagartija y ratón. También se determinó si la abundancia de insectos necrófagos y depredadores difiere dependiendo del tipo de cebo que se utilice. Se recolectaron 13 especies de Silphidae, Staphylinidae (Coleoptera, Calliphoridae y Sarcophagidae (Diptera; ningún tipo de cebo logró atraer a todas las especies. Se encontró que la abundancia de 5 de las especies difirió significativamente dependiendo del cebo utilizado. La abundancia de los insectos depredadores fue menor que la de los carroñeros en los cebos de lagartija y ratón. Estos resultados muestran que la evaluación de la estructura de una comunidad de insectos necrófilos puede depender del tipo de cebo que se utilice.

  18. The effect of genetically enriched (E)-β-ocimene and the role of floral scent in the attraction of the predatory mite Phytoseiulus persimilis to spider mite-induced volatile blends of torenia.

    Science.gov (United States)

    Shimoda, Takeshi; Nishihara, Masahiro; Ozawa, Rika; Takabayashi, Junji; Arimura, Gen-ichiro

    2012-03-01

    Plants under herbivore attack emit mixtures of volatiles (herbivore-induced plant volatiles, HIPVs) that can attract predators of the herbivores. Although the composition of HIPVs should be critical for the attraction, most studies of transgenic plant-emitted volatiles have simply addressed the effect of trans-volatiles without embedding in other endogenous plant volatiles. We investigated the abilities of transgenic wishbone flower plants (Torenia hybrida and Torenia fournieri) infested with spider mites, emitting a trans-volatile ((E)-β-ocimene) in the presence or absence of endogenous volatiles (natural HIPVs and/or floral volatiles), to attract predatory mites (Phytoseiulus persimilis). In both olfactory- and glasshouse-based assays, P. persimilis females were attracted to natural HIPVs from infested wildtype (wt) plants of T. hybrida but not to those of T. fournieri. The trans-volatile enhanced the ability to attract P. persimilis only when added to an active HIPV blend from the infested transgenic T. hybrida plants, in comparison with the attraction by infested wt plants. Intriguingly, floral volatiles abolished the enhanced attractive ability of T. hybrida transformants, although floral volatiles themselves did not elicit any attraction or avoidance behavior. Predator responses to trans-volatiles were found to depend on various background volatiles (e.g. natural HIPVs and floral volatiles) endogenously emitted by the transgenic plants. © 2012 The Authors. New Phytologist © 2012 New Phytologist Trust.

  19. Rapid biosynthesis of silver nanoparticles using Crotalaria verrucosa leaves against the dengue vector Aedes aegypti: what happens around? An analysis of dragonfly predatory behaviour after exposure at ultra-low doses.

    Science.gov (United States)

    Murugan, Kadarkarai; Sanoopa, C P; Madhiyazhagan, Pari; Dinesh, Devakumar; Subramaniam, Jayapal; Panneerselvam, Chellasamy; Roni, Mathath; Suresh, Udaiyan; Nicoletti, Marcello; Alarfaj, Abdullah A; Munusamy, Murugan A; Higuchi, Akon; Kumar, Suresh; Perumalsamy, Haribalan; Ahn, Young-Joon; Benelli, Giovanni

    2016-01-01

    Aedes aegypti is a primary vector of dengue, a mosquito-borne viral disease infecting 50-100 million people every year. Here, we biosynthesised mosquitocidal silver nanoparticles (AgNP) using the aqueous leaf extract of Crotalaria verrucosa. The green synthesis of AgNP was studied by UV-vis spectroscopy, SEM, EDX and FTIR. C. verrucosa-synthesised AgNPs were toxic against A. aegypti larvae and pupae. LC50 of AgNP ranged from 3.496 ppm (I instar larvae) to 17.700 ppm (pupae). Furthermore, we evaluated the predatory efficiency of dragonfly nymphs, Brachydiplax sobrina, against II and III instar larvae of A. aegypti in an aquatic environment contaminated with ultra-low doses of AgNP. Under standard laboratory conditions, predation after 24 h was 87.5% (II) and 54.7% (III). In an AgNP-contaminated environment, predation was 91 and 75.5%, respectively. Overall, C. verrucosa-synthesised AgNP could be employed at ultra-low doses to reduce larval population of dengue vectors enhancing predation rates of dragonfly nymphs.

  20. Influence of the webbing produced by Oligonychus ilicis (McGregor) (Acari: Tetranychidae) on associated predatory phytoseiids; Influencia da teia de Oligonychus ilicis (McGregor) (Acari: Tetranychidae) sobre os fitoseideos predadores associados

    Energy Technology Data Exchange (ETDEWEB)

    Franco, Renato A. [Bioagri Laboratorios Ltda., Piracicaba, SP (Brazil)], e-mail: r.franco@bioagri.com.br; Reis, Paulo R. [Empresa de Pesquisa Agropecuaria de Minas Gerais (EPAMIG), Belo Horizonte, MG (Brazil). Ecocentro], e-mail: paulo.rebelles@epamig.ufla.br; Zacarias, Mauricio S. [EMBRAPA Cafe, Lavras, MG (Brazil)], e-mail: zacarias@epamig.ufla.br; Oliveira, Daniel C. [Universidade Federal de Lavras (UFLA), MG (Brazil)

    2010-01-15

    Oligonychus ilicis (McGregor) is among those mite species that can cause damage to coffee plants (Coffea spp.). Species of Phytoseiidae acari are considered the most important and studied predatory mites. The objective of this study was to evaluate the effects of the webbing produced by O. ilicis on its predation by females of the phytoseiids Iphiseiodes zuluagai Denmark and Muma, Euseius citrifolius Denmark and Muma and Amblyseius herbicolus (Chant). Four bioassays were conducted, with three treatments and ten replicates. Each replicate consisted of 25 O. ilicis per experimental unit (a leaf disc of Coffea arabica) according to the tested developmental stage, in independent experiments. To spin the web, 15 adult females were put on each experimental unit for 24h; females were then removed, leaving only the web, and predators and prey to be tested were introduced. Predation was assessed after 24h. In the presence of webbing, the consumption of eggs, larvae and nymphs by I. zuluagai and eggs and larvae by E. citrifolius was lower. For A. herbicolus, egg predation was lower, but larval predation did not vary significantly and predation of nymphs and adults was higher in the presence of webbing. Predators as a whole were more efficient consuming larvae regardless of the presence of webbing. Considering the stages of O. ilicis altogether, webbing reduced the predation potential of I. zuluagai and E. citrifolius, but not of A. herbicolus. (author)

  1. Scanning electron microscopy of the predatory ability of agents of the biocontrol of nematodes/ Microscopia eletrônica de varredura da habilidade predatória de agentes do biocontrole de nematóides

    Directory of Open Access Journals (Sweden)

    João Carlos de Oliveira

    2001-08-01

    Full Text Available Nematode-trapping fungi have been studied as a promising alternative to control bovine gastrointestinal parasites and plant parasitic nematodes. Some encouraging results have been achieved with some species, by many researchers. Nematophagous fungi such as Arthrobotrys javanica, Dactylella leptospora, Monacrosporium eudermatum, M. robustum e Nematoctonus campylosporus were isolated from soil samples collected from different crops and agronomic environments proceeding from varies places in Brazil, making use of soil spreading methods. These fungi species were isolated at the Center of Animal Parasitology (CPPAR at UNESP/FCAV, Campus Jaboticabal – SP. The predatory ability of these fungi, on free living nematodes (Panagrellus sp. was documented at the Scanning Electron Microscopy Lab. The objectives of this work were to document, through Scanning Electron Microscopy (SEM, the morphological structures of these fungi, such as: capturing structures, size, form, septation of the conidia, connection clamp, exclusively on N. campylosporus, as well as the free-living nematodes captured by these fungi.Fungos nematófagos têm sido estudados como uma alternativa promissora para o manejo de nematóides de plantas e parasitos gastrintestinais de bovinos. Resultados encorajadores têm sido obtidos com algumas espécies, por vários pesquisadores. A partir de amostras de solo coletadas em diferentes culturas e agroecossistemas provenientes de diversas localidades do Brasil, foram isolados, pelo método de espalhamento de solo, os fungos nematófagos Arthrobotrys javanica, Dactylella leptospora, Monacrosporium eudermatum, M. robustum e Nematoctonus campylosporus, no Centro de Pesquisas em Sanidade Animal (CPPAR da UNESP/FCAV, Câmpus de Jaboticabal - SP, e a habilidade predatória destes fungos sobre o nematóide de vida livre Panagrellus sp. foi estudada no Laboratório de Microscopia Eletrônica de Varredura. Este trabalho teve como objetivo documentar ao

  2. Temperature rise and microplastics interact with the toxicity of the antibiotic cefalexin to juveniles of the common goby (Pomatoschistus microps): Post-exposure predatory behaviour, acetylcholinesterase activity and lipid peroxidation.

    Science.gov (United States)

    Fonte, Elsa; Ferreira, Pedro; Guilhermino, Lúcia

    2016-11-01

    The goal of this study was to investigate the toxicity of cefalexin to Pomatoschistus microps juveniles in relation to the presence of microplastics in the water and temperature rise. After acclimatization, groups of wild juveniles were exposed for 96h to artificial salt water (control), microplastics alone (0.184mg/l), cefalexin alone (1.3-10mg/l) and in mixture with microplastics (cefalexin: 1.3-10mg/l; microplastics: 0.184mg/l) at 20 and 25°C. Effect criteria were mortality, post-exposure predatory performance (PEPP), acetylcholinesterase activity (AChE) and lipid peroxidation levels (LPO). At 20°C, concentrations of cefalexin alone≥5mg/l significantly reduced PEPP (up to 56%; 96h-EC 50 =8.4mg/l), indicating toxicity of the antibiotic to juveniles after short-term exposure to water concentrations in the low ppm range. At 20°C, fish exposed to microplastics alone did not have significant differences in any of the parameters tested relative to the control group but tended to have an inhibition of the PEPP (23%) and AChE (21%); at 25°C, microplastics alone caused mortality (33%) and PEPP inhibition (28%). Thus, microplastics are toxic to P. microps juveniles. At 20°C, under simultaneous exposure to cefalexin and microplastics, the PEPP was significantly reduced (at cefalexin concentrations≥1.25mg/l). Moreover, at 25°C, the toxicity curves of cefalexin (PEPP based), alone and in mixture with microplastics, were significantly different (pmicroplastics in the water influenced the toxicity of cefalexin. The rise of water temperature (from 20°C to 25°C), increased the microplastics-induced mortality (from 8 to 33%), and the inhibitory effects of cefalexin on the PEPP (up to 70%). Significant differences (pmicroplastics and of cefalexin, alone and in mixture with microplastics, to P. microps juveniles. These findings raise concern on the long-term exposure of wild populations to complex mixtures of pollutants, likely decreasing their fitness, and highlight

  3. Domatia reduce larval cannibalism in predatory mites

    NARCIS (Netherlands)

    Ferreira, J.A.M.; Eshuis, B.; Janssen, A.; Sabelis, M.W.

    2008-01-01

    1. Acarodomatia are small structures on the underside of leaves of many plant species, which are mainly inhabited by carnivorous and fungivorous mites. 2. Domatia are thought to protect these mites against adverse environmental conditions and against predation. They are considered as an indirect

  4. The Pollution Of Science: Plagiarism & Predatory Journal

    OpenAIRE

    Abdelkrim CHERITI

    2015-01-01

    In 2013 we denounced a case of plagiarism, a stupid copy and paste of our article published since 2012 in this journal (PhytoChem & BioSub Journal Vol. 6 N° 2, 83-87, 2012) by another “ scientists” - teaching in Tlemcen and Bechar universities, L. Ziane, H. A. Lazouni, A. Moussaoui, N. Hamidi - and published in Asian Journal of Natural & Applied Sciences, Vol. 2(1), 5-9, 2013 (www. leena-luna.co.jp). A journal with editorial board but the editor chief is anonymous. the same "au...

  5. Effects of predation and food on the population dynamics of the raptorial cladoceran Leptodora kindtii

    NARCIS (Netherlands)

    Vijverberg, J.; Koelewijn, H.P.; Densen, van W.L.T.

    2005-01-01

    We assessed the trophic status of Leptodora kindtii in the food web of a shallow, eutrophic lake in which 0+ age group fish were the main predators. The mean biomass of 0+ fish during three successive years varied from 0.39 g dry wt m(-2) in the first year to 0.05 g dry wt m(-2)in the second year to

  6. Effects of predation and food on the population dynamics of the raptorial cladoceran Leptodora kindtii

    NARCIS (Netherlands)

    Vijverberg, J.; Koelewijn, H.P.; Van Densen, W.L.T.

    2005-01-01

    We assessed the trophic status of Leptodora kindtii in the food web of a shallow, eutrophic lake in which 0+ age group fish were the main predators. The mean biomass of 0+ fish during three successive years varied from 0.39 g dry wt m-2 in the first year to 0.05 g dry wt m-22 in the second year to

  7. CHRONIC EFFECTS OF THE HERBICIDE DIURON ON FRESHWATER CLADOCERANS,AMPHIPODS,MIDGES,MINNOWS,WORMS, AND SNAILS

    Science.gov (United States)

    The chronic effects of the herbicide diuron on survival and reproduction of Daphnia pulex, and survival and growth of the amphipod Hyalella azteca, the midge Chironomus tentans, juvenile and embro/larval fathead minnows, Pimephales promelas, annelid worms, Lumbriculus variegatus,...

  8. Effects of inorganic turbidity and reservoir floods on the feeding and population dynamics of Cladoceran zooplankton

    International Nuclear Information System (INIS)

    Shuman, J.R.

    1988-01-01

    Clearance rates of 32 P-labeled yeast cell tracer particles and gravimetric seston analysis were used to estimate in situ seston ingestion rates of Daphnia parvula and Bosmina along the seston gradient in Tuttle Creek Reservoir, near Manhattan, Kansas. An ingestion rate depression occurred for both species at the highest seston concentration. The smallest animals, Bosmina, had a lower incipient limiting concentration and exhibited a stronger ingestion rate depression. The fecundity and abundance of Daphnia parvula, grown in enclosures along the seston gradient prior to the ingestion rate measurements, were highest at the river inflow region. Reservoir Bosmina, however, were least abundant and had the lowest fecundity at the river inflow region. The abundance of Bosmina, calanoid copepods, and cyclopoid copepods were lower following large storm inflows in the late spring of 1983 and 1984, while the abundance of Diaphanosoma and Moina were similar. Both open reservoir and in situ enclosure populations of Daphnia pulex were reduced following the storm inflow, while only enclosure populations of Daphnia parvula were lower. Diaphanosoma and calanoid copepods dominated the zooplankton during sampling from spring through fall 1984, particularly in midsummer when temperatures were greater than 25 degree C. Daphnids dominated numerically during the fall baseflow period

  9. Environmentally-induced plasticity of life history parameters in the cladoceran Simocephalus vetulus

    Czech Academy of Sciences Publication Activity Database

    Šorf, Michal; Cábová, M.; Rychtecký, Pavel

    2017-01-01

    Roč. 66, SEP 01 (2017), s. 40-43 ISSN 0075-9511 R&D Projects: GA ČR(CZ) GA14-29857S Institutional support: RVO:60077344 Keywords : cladocera * life history traits * feeding Subject RIV: EH - Ecology, Behaviour OBOR OECD: Ecology Impact factor: 1.427, year: 2016 http://www.sciencedirect.com/science/article/pii/S007595111630192X

  10. Effect of temperature on development and growth of the raptorial cladoceran Leptodora kindtii under laboratory conditions

    NARCIS (Netherlands)

    Vijverberg, J.; Koelewijn, H.P.

    2004-01-01

    1. Leptodora is a key species in many temperate freshwater systems, but so far its role in the food web could not be properly evaluated because detailed information about its secondary production was lacking. As we wanted to estimate the secondary production of Leptodora, we measured its development

  11. Mortalidade do ácaro predador Neoseiulus californicus (Acari: Phytoseiidae em testes de toxicidade residual de inseticidas e acaricidas usuais em pomáceas Mortality of predatory mite Neoseiulus californicus (Acari: Phytoseiidae in residual toxicity persistence tests

    Directory of Open Access Journals (Sweden)

    Marcelo Gustavo Ruiz

    2008-12-01

    .01 the negative linear regression obtained. Tested acaricides produced the greatest negative effects on the survival of N. californicus. Azimphos-methyl was the pesticide that least affected the survival of the predatory mite. Tested insecticides, used in the "Alto Valle del Río Negro y Neuquén" region to control codling moth, C. pomonella, key pest of pip fruit crops, showed low toxicity to N. californicus.

  12. Effect of aqueous extracts of black alder (Alnus glutinosa (LINNAEUS, 1753 GAERTNER, 1791 and elder (Sambucus nigra LINNAEUS, 1753 on the occurrence of Brevicoryne brassicae LINNAEUS, 1758 (Hemiptera, Aphidoidea, its parasitoid Diaeretiella rapae (M’INTOSH, 1855 (Hymenoptera, Ichneumonoidea and predatory Syrphidae on white cabbage

    Directory of Open Access Journals (Sweden)

    Jankowska Beata

    2016-06-01

    Full Text Available The insecticidal and antifeedant effects of aqueous extracts from two common plants (black alder Alnus glutinosa and elder Sambucus nigra on the occurrence of Brevicoryne brassicae, its parasitoid Diaeretiella rapae and predatory Syrphidae on white cabbage were investigated in 2008-2009. Both extracts reduced the number of cabbage aphids, although the Sambucus nigra extract proved to have a better effect. Differences were seen both in the numbers of winged aphids settling on plants and in the overall numbers of aphids on plants during the entire season. There were no significant differences in the degree of parasitization by Diaeretiella rapae in the three experimental combinations. Eight species of Syrphidae were found in the Brevicoryne brassicae colonies: Episyrphus balteatus, Sphaerophoria scripta, S. rueppelli, S. menthastri, Eupeodes corollae, Scaeva pyrastri, Scaeva selenitica and Syrphus vitripennis. The dominant species was Episyrphus balteatus. The largest numbers of syrphid larvae and pupae were collected from cabbage aphid colonies on the control plants. Smaller numbers were recorded on the plot where the cabbages were sprayed with the Sambucus nigra extract. The results of this study indicate that botanical insecticides based on S. nigra have the potential to be incorporated into control programmes for the cabbage aphid.

  13. Development of the Cladoceran Community in Dallund Sø, Denmark, during the last 7000 Years - Based on Macrofossils in the Sediment

    DEFF Research Database (Denmark)

    Johansson, L. S.; Bradshaw, E.; Jeppesen, E.

    Organised by Balaton Limnological Research Institute of the Hungarian Academy of Science, Tihany, and Institute of Biology, university of Veszprém......Organised by Balaton Limnological Research Institute of the Hungarian Academy of Science, Tihany, and Institute of Biology, university of Veszprém...

  14. Transgenerational effects and recovery of microplastics exposure in model populations of the freshwater cladoceran Daphnia magna Straus.

    Science.gov (United States)

    Martins, Alexandra; Guilhermino, Lúcia

    2018-08-01

    The environmental contamination by microplastics is a global challenge to ecosystem and human health, and the knowledge on the long-term effects of such particles is limited. Thus, the effects of microplastics and post-exposure recovery were investigated over 4 generations (F 0 , F 1 , F 2 , F 3 ) using Daphnia magna as model. Effect criteria were parental mortality, growth, several reproductive parameters, and population growth rate. Microplastics exposure (0.1mg/l of pristine polymer microspheres 1-5μm diameter) caused parental mortality (10-100%), and significantly (p≤0.05) decreased growth, reproduction, and population growth rate leading to the extinction of the microplastics-exposed model population in the F 1 generation. Females descending from those exposed to microplastics in F 0 and exposed to clean medium presented some recovery but up to the F 3 generation they still had significantly (p≤0.05) reduced growth, reproduction, and population growth rate. Overall, these results indicate that D. magna recovery from chronic exposure to microplastics may take several generations, and that the continuous exposure over generations to microplastics may cause population extinction. These findings have implications to aquatic ecosystem functioning and services, and raise concern on the long-term animal and human exposure to microplastics through diverse routes. Copyright © 2018. Published by Elsevier B.V.

  15. Arginine kinase in the cladoceran Daphnia magna: cDNA sequencing and expression is associated with resistance to toxic Microcystis.

    Science.gov (United States)

    Lyu, Kai; Zhang, Lu; Zhu, Xuexia; Cui, Guilian; Wilson, Alan E; Yang, Zhou

    2015-03-01

    Nutrient loading derived from anthropogenic activities into lakes have increased the frequency, severity and duration of toxic cyanobacterial blooms around the world. Although herbivorous zooplankton are generally considered to be unable to control toxic cyanobacteria, populations of some zooplankton, including Daphnia, have been shown to locally adapt to toxic cyanobacteria and suppress cyanobacterial bloom formation. However, little is known about the physiology of zooplankton behind this phenomenon. One possible explanation is that some zooplankton may induce more tolerance by elevating energy production, thereby adding more energy allocation to detoxification expenditure. It is assumed that arginine kinase (AK) serves as a core in temporal and spatial adenosine triphosphate (ATP) buffering in cells with high fluctuating energy requirements. To test this hypothesis, we studied the energetic response of a single Daphnia magna clone exposed to a toxic strain of Microcystis aeruginosa, PCC7806. Arginine kinase of D. magna (Dm-AK) was successfully cloned. An ATP-gua PtransN domain which was described as a guanidine substrate specificity domain and an ATP-gua Ptrans domain which was responsible for binding ATP were both identified in the Dm-AK. Phylogenetic analysis of AKs in a range of arthropod taxa suggested that Dm-AK was as dissimilar to other crustaceans as it was to insects. Dm-AK transcript level and ATP content in the presence of M. aeruginosa were significantly lower than those in the control diet containing only the nutritious chlorophyte, Scenedesmus obliquus, whereas the two parameters in the neonates whose mothers had been previously exposed to M. aeruginosa were significantly higher than those of mothers fed with pure S. obliquus. These findings suggest that Dm-AK might play an essential role in the coupling of energy production and utilization and the tolerance of D. magna to toxic cyanobacteria. Copyright © 2014 Elsevier B.V. All rights reserved.

  16. A laboratory study of functional response of ILeptodora kindtii/I to some cladoceran species and copepod nauplii

    Czech Academy of Sciences Publication Activity Database

    Pichlová, Radka; Vijverberg, J.

    2001-01-01

    Roč. 150, č. 4 (2001), s. 529-544 ISSN 0003-9136 Institutional research plan: CEZ:AV0Z6017912 Keywords : predation rates * predator-size * prey-size Subject RIV: DA - Hydrology ; Limnology Impact factor: 1.186, year: 2001

  17. Environmental boundaries of marine cladoceran distributions in the NW Mediterranean: Implications for their expansion under global warming

    KAUST Repository

    Atienza, Dacha; Sabaté s, Ana; Isari, Stamatina; Saiz, Enric; Calbet, Albert

    2016-01-01

    in the southern region, where temperatures are warmer, and its populations develop northward during the summer. Evadne-Pseudevadne did not show a clear pattern, likely because several species were pooled. In 2003 successive heat waves affecting southwestern Europe

  18. Deciphering mechanisms of malathion toxicity under pulse exposure of the freshwater cladoceran Daphnia magna

    DEFF Research Database (Denmark)

    Trác, Ngoc Lâm; Andersen, Ole; Palmqvist, Annemette

    2016-01-01

    ; enzyme activities of acetylcholinesterase (AChE), carboxylesterase (CbE), and glutathione S-transferase (GST); and AChE gene expression. The results showed no difference in survival among equivalent integrated doses. Adverse sublethal effects were driven by exposure concentration rather than pulse...... duration. Specifically, short pulse exposure to a high concentration of malathion resulted in more immobilized daphnids, lower AChE and CbE activities, and a higher transcript level ofAChE gene compared with long pulse exposure to low concentration. The expression of the AChE gene was up...

  19. Predatory Publishing Is a Threat to Non-Mainstream Science

    Science.gov (United States)

    Nurmashev, Bekaidar

    2017-01-01

    This article highlights the issue of wasteful publishing practices that primarily affect non-mainstream science countries and rapidly growing academic disciplines. Numerous start-up open access publishers with soft or nonexistent quality checks and huge commercial interests have created a global crisis in the publishing market. Their publishing practices have been thoroughly examined, leading to the blacklisting of many journals by Jeffrey Beall. However, it appears that some subscription journals are also falling short of adhering to the international recommendations of global editorial associations. Unethical editing agencies that promote their services in non-mainstream science countries create more problems for inexperienced authors. It is suggested to regularly monitor the quality of already indexed journals and upgrade criteria of covering new sources by the Emerging Sources Citation Index (Web of Science), Scopus, and specialist bibliographic databases. Regional awareness campaigns to inform stakeholders of science communication about the importance of ethical writing, transparency of editing services, and permanent archiving can be also helpful for eradicating unethical publishing practices. PMID:28378542

  20. Nutrient-mediated architectural plasticity of a predatory trap.

    Directory of Open Access Journals (Sweden)

    Sean J Blamires

    Full Text Available BACKGROUND: Nutrients such as protein may be actively sought by foraging animals. Many predators exhibit foraging plasticity, but how their foraging strategies are affected when faced with nutrient deprivation is largely unknown. In spiders, the assimilation of protein into silk may be in conflict with somatic processes so we predicted web building to be affected under protein depletion. METHODOLOGY/PRINCIPAL FINDINGS: To assess the influence of protein intake on foraging plasticity we fed the orb-web spiders Argiope aemula and Cyclosa mulmeinensis high, low or no protein solutions over 10 days and allowed them to build webs. We compared post-feeding web architectural components and major ampullate (MA silk amino acid compositions. We found that the number of radii in webs increased in both species when fed high protein solutions. Mesh size increased in A. aemula when fed a high protein solution. MA silk proline and alanine compositions varied in each species with contrasting variations in alanine between the two species. Glycine compositions only varied in C. mulmeinensis silk. No spiders significantly lost or gained mass on any feeding treatment, so they did not sacrifice somatic maintenance for amino acid investment in silk. CONCLUSIONS/SIGNIFICANCE: Our results show that the amount of protein taken in significantly affects the foraging decisions of trap-building predators, such as orb web spiders. Nevertheless, the subtle differences found between species in the association between protein intake, the amino acids invested in silk and web architectural plasticity show that the influence of protein deprivation on specific foraging strategies differs among different spiders.

  1. Nutrient-mediated architectural plasticity of a predatory trap.

    Science.gov (United States)

    Blamires, Sean J; Tso, I-Min

    2013-01-01

    Nutrients such as protein may be actively sought by foraging animals. Many predators exhibit foraging plasticity, but how their foraging strategies are affected when faced with nutrient deprivation is largely unknown. In spiders, the assimilation of protein into silk may be in conflict with somatic processes so we predicted web building to be affected under protein depletion. To assess the influence of protein intake on foraging plasticity we fed the orb-web spiders Argiope aemula and Cyclosa mulmeinensis high, low or no protein solutions over 10 days and allowed them to build webs. We compared post-feeding web architectural components and major ampullate (MA) silk amino acid compositions. We found that the number of radii in webs increased in both species when fed high protein solutions. Mesh size increased in A. aemula when fed a high protein solution. MA silk proline and alanine compositions varied in each species with contrasting variations in alanine between the two species. Glycine compositions only varied in C. mulmeinensis silk. No spiders significantly lost or gained mass on any feeding treatment, so they did not sacrifice somatic maintenance for amino acid investment in silk. Our results show that the amount of protein taken in significantly affects the foraging decisions of trap-building predators, such as orb web spiders. Nevertheless, the subtle differences found between species in the association between protein intake, the amino acids invested in silk and web architectural plasticity show that the influence of protein deprivation on specific foraging strategies differs among different spiders.

  2. Helminths of Wild Predatory Mammals (Mammalia, Carnivora of Ukraine. Trematodes

    Directory of Open Access Journals (Sweden)

    Korol E. N.

    2016-08-01

    Full Text Available The paper summarises information on 11 species of trematodes parasitic in 9 species of wild carnivorans of Ukraine. The largest number of trematode species (9 was found in the red fox (Vulpes vulpes. Alaria alata (Diplostomidae appeared to be the most common trematode parasite in the studied group; it was found in 4 host species from 9 administrative regions and Crimea.

  3. A new metric for measuring condition in large predatory sharks.

    Science.gov (United States)

    Irschick, D J; Hammerschlag, N

    2014-09-01

    A simple metric (span condition analysis; SCA) is presented for quantifying the condition of sharks based on four measurements of body girth relative to body length. Data on 104 live sharks from four species that vary in body form, behaviour and habitat use (Carcharhinus leucas, Carcharhinus limbatus, Ginglymostoma cirratum and Galeocerdo cuvier) are given. Condition shows similar levels of variability among individuals within each species. Carcharhinus leucas showed a positive relationship between condition and body size, whereas the other three species showed no relationship. There was little evidence for strong differences in condition between males and females, although more male sharks are needed for some species (e.g. G. cuvier) to verify this finding. SCA is potentially viable for other large marine or terrestrial animals that are captured live and then released. © 2014 The Fisheries Society of the British Isles.

  4. Role of Predatory Mites in Persistent Nonoccupational Allergic Rhinitis

    Directory of Open Access Journals (Sweden)

    Paloma Poza Guedes

    2016-01-01

    Full Text Available Mites can sensitize and induce atopic disease in predisposed individuals and are an important deteriorating factor in patients with allergic rhinitis, asthma, and atopic dermatitis. Although Pyroglyphidae mites have been extensively studied, very scarce reports are available on Cheyletidae spp. especially regarding human respiratory pathology. The main objective of the present study is to investigate the clinical role of this predator mite (Cheyletus eruditus as a respiratory antigen in a selected sensitized human population. Fifty-two adult patients were recruited from the outpatient allergy clinic to assess their eligibility for the study. The thirty-seven subjects with persistent allergic rhinitis (PAR who fulfilled the ARIA criteria had a positive IgE response confirmed by skin prick test (SPT to C. eruditus. Only those individuals (37/47 with a positive SPT to C. eruditus showed a positive nasal provocation test (NPT, while 10 patients with nonallergic mild-to-moderate persistent rhinitis, control group, had a negative NPT with C. eruditus. The present paper describes a new role for the predator mite Cheyletus eruditus as a respiratory allergen in a selected subset of patients in a subtropical environment afflicted with persistent nonoccupational allergic rhinitis.

  5. Sociobiology of biodegradation and the role of predatory protozoa in ...

    Indian Academy of Sciences (India)

    PRAKASH KUMAR

    advantageous for cheaters to remain mobile or free floating as they depend upon the ..... up a number of possible applications of sociobiology in fields such as ... bacteriennes, PhD thesis, University of Paris , Paris, France. Orpin C G and ...

  6. Egg morphology of the predatory mite, Cheyletus malaccensis (Acarina: Cheyletidae)

    Czech Academy of Sciences Publication Activity Database

    Kučerová, Z.; Hromádková, Jiřina

    2009-01-01

    Roč. 32, č. 1 (2009), s. 35-40 ISSN 0171-8177 Institutional research plan: CEZ:AV0Z40500505 Keywords : Cheyletus malaccensis Oudemans 1903 * biocontrol * eggshell surface structure Subject RIV: GF - Plant Pathology, Vermin, Weed, Plant Protection Impact factor: 0.618, year: 2009

  7. Evolution of slow and fast development in predatory ladybirds

    Czech Academy of Sciences Publication Activity Database

    Dixon, Anthony F. G.; Sato, S.; Kindlmann, Pavel

    2016-01-01

    Roč. 140, 1-2 (2016), s. 103-114 ISSN 0931-2048 R&D Projects: GA MŠk(CZ) LO1415; GA ČR GB14-36098G Institutional support: RVO:67179843 Keywords : aphid consumption * growth polymorphism * ladybirds * optimum growth rate * rate of development * survival Subject RIV: EH - Ecology, Behaviour Impact factor: 1.641, year: 2016

  8. The utility of predatory fish in biomanipulation of deep reservoirs

    Czech Academy of Sciences Publication Activity Database

    Vašek, Mojmír; Prchalová, Marie; Peterka, Jiří; Ketelaars, H. A. M.; Wagenvoort, A. J.; Čech, Martin; Draštík, Vladislav; Říha, Milan; Jůza, Tomáš; Kratochvíl, Michal; Mrkvička, Tomáš; Blabolil, Petr; Boukal S., David; Duras, J.; Kubečka, Jan

    2013-01-01

    Roč. 52, March (2013), s. 104-111 ISSN 0925-8574 R&D Projects: GA MZe(CZ) QH81046; GA MŠk(CZ) EE2.3.20.0204 Institutional support: RVO:60077344 Keywords : biomanipulation * eutrophication * top-down control * water quality * piscivores * recreational fishing Subject RIV: EH - Ecology, Behaviour Impact factor: 3.041, year: 2013

  9. Health effects of predatory beneficial mites and wasps in greenhouses

    DEFF Research Database (Denmark)

    Bælum, Jesper; Enkegaard, Annie; Doekes, Gert

    A three-year study of 579 greenhouse workers in 31 firms investigated the effect of four different beneficial arthropods. It was shown that the thrips mite Amblyseeius cucumeris and the spider mite predator Phytoseiulus persimilis may cause allergy measured by blood tests as well as eye and nose...... symptoms. No effect was seen by the predator wasp Aphidius colemani nor the predator mite Hypoaspis miles and no effect on lung diseases were seen....

  10. Diet and Predatory Behavior of Lynx in Sweden

    DEFF Research Database (Denmark)

    Moshøj, Charlotte Margaret

    2002-01-01

    and hunters who fear predation on livestock and reindeer as well as a general reduction in wild game abundance, especially roe deer (Capreolus capreolus). Prey spectrum and predation of lynx was studied based on stomach analyses of lynx throughout Sweden and on data from a field study in south-central Sweden...... (reindeer and roe deer) comprised the greatest part of the diet, while a regional division indicated that while lynxes from northern regions had a narrower diet niche, they were in better condition than lynxes from south of the reindeer husbandry districts. Lynx gender and status also influenced diet...

  11. Letter to the editor: Predatory Publishers and Plagiarism Prevention

    NARCIS (Netherlands)

    Jansen, P.A.; Forget, P.M.

    2012-01-01

    M. Balter (“Reviewer's Déjà Vu, French science sleuthing uncover plagiarized papers,” News & Analysis, 9 March, p. 1157) describes how a scientist recently published at least nine articles that largely or entirely duplicated papers written by others and was exposed only after we found one of our

  12. Differences in predatory pressure on terrestrial snails by birds and ...

    Indian Academy of Sciences (India)

    Supplementary table 2. Number of collected individuals of particular morph categories of C. nemoralis and C. hortensis with specification of undamaged and damaged snails. Morph. Total number of individuals. Undamaged individuals. Shells damaged by. Mice. Birds. Mouse + bird. Cepaea nemoralis. 732. 172. 105. 436.

  13. Physiological mechanism governing slow and fast development in predatory ladybirds

    Czech Academy of Sciences Publication Activity Database

    Dixon, Anthony F. G.; Honěk, A.; Jarošík, Vojtěch

    2013-01-01

    Roč. 38, č. 1 (2013), s. 26-32 ISSN 0307-6962 R&D Projects: GA ČR GA206/09/0563; GA MŠk LC06073; GA MŠk ED1.1.00/02.0073 Institutional support: RVO:67179843 ; RVO:67985939 Keywords : Coccinellidae * food quality * geographical distribution Subject RIV: EH - Ecology, Behaviour; EH - Ecology, Behaviour (UEK-B) Impact factor: 1.434, year: 2013

  14. Saving the Predators: Teaching About the Role of Predatory Animals.

    Science.gov (United States)

    Soltow, Willow

    1985-01-01

    Discusses the role of predators in regulating prey populations, noting that this is an excellent example of the "interconnectedness" of life. Suggestions for films, books, articles, and student questions are given, and a special section dealing with human attitudes about predators is provided. (DH)

  15. The predatory impact of invasive alien smallmouth bass, Micropterus ...

    African Journals Online (AJOL)

    Teleostei: Centrarchidae), on indigenous fishes in a Cape Floristic Region ... The Rondegat River is home to five species of indigenous fish and is partially invaded by M. dolomieu, which has penetrated the lower river up to a waterfall barrier.

  16. Non-obligate predatory bacterium burkholderia casidaeand uses thereof

    OpenAIRE

    1998-01-01

    A novel predator bacterium Burkholderia casidae is disclosed. The invention is directed to the isolation and use of Burkholderia casidae to control microbial diseases of plants. The genetic, biochemical and physiological characteristics of Burkholderia casidae are described. Biocontrol compositions comprising Burkholderia casidae, and antimicrobial compounds and antimicrobial preparations prepared from Burkholderia casidae are also disclosed, as are methods for accomplishing all of the forego...

  17. Non-obligate predatory bacterium Burkholderia casidae and uses thereof

    OpenAIRE

    2001-01-01

    A novel predator bacterium Burkholderia casidae is disclosed. The invention is directed to the isolation and use of Burkholderia casidae to control microbial diseases of plants. The genetic, biochemical and physiological characteristics of Burkholderia casidae are described. Biocontrol compositions comprising Burkholderia casidae, and antimicrobial compounds and antimicrobial preparations prepared from Burkholderia casidae are also disclosed, as are methods for accomplishing all of the forego...

  18. Potential Impact of Mediterranean Aquaculture on the Wild Predatory Bluefish

    OpenAIRE

    Miralles, Laura; Mrugala, Agata; Sanchez-Jerez, Pablo; Juanes, Francis; Garcia-Vazquez, Eva

    2016-01-01

    Aquaculture impacts on wild populations of fish have been considered principally due to farm escapes. The Bluefish Pomatomus saltatrix, which exhibits two distinct genetic units in the Mediterranean Sea, is a voracious predator and is attracted to aquaculture cages to prey on farmed fish, particularly Gilthead Seabream Sparus aurata and European Sea Bass Dicentrarchus labrax. We compared the genetic diversity of adult Bluefish caught inside one aquaculture farm located in Spanish waters of th...

  19. Seletividade de acaricidas e inseticidas a ácaros predadores (Acari: Phytoseiidae encontrados em seringueira no centro-oeste do Brasil Side-effect of acaricides and insecticides to predatory mites (Acari: Phytoseiidae found in rubber-trees in mid-west Brazil

    Directory of Open Access Journals (Sweden)

    Noeli Juarez Ferla

    2006-04-01

    Full Text Available Euseius concordis (Chant e Neoseiulus anonymus (Chant & Baker são ácaros predadores da família Phytoseiidae comumente encontrados em seringueira (Hevea brasiliensis Muell. Arg. em Mato Grosso, região centro-oeste do Brasil. Este trabalho foi realizado para verificar o efeito de acaricidas e inseticidas-acaricidas empregados em plantações de seringueira, e outros que teriam potencial para serem empregados contra insetos e ácaros considerados pragas dessa cultura, sobre E. concordis e N. anonymus. Utilizou-se o método residual de pulverização em superfície, recomendado como padrão pelo Grupo de Trabalho "Pesticidas e Artrópodes Benéficos", da Organização Internacional de Controle Biológico e Integrado de Plantas e Animais Nocivos/Seção Regional do Paleártico Oeste. Duas concentrações de cada um dos seguintes ingredientes ativos foram utilizadas: acefato, dicofol, endosulfan, formetanate, metomil, monocrotofós, óxido de fenbutatin e propargite. Uma das concentrações utilizadas foi uma média daquelas sugeridas pelos fabricantes para o controle de ácaros e insetos fitófagos presentes em outras culturas, uma vez que nenhum dos produtos testados tem registro para o uso em seringueira e a outra correspondeu à cerca de um terço da primeira. Endosulfan a 320ppm, dicofol a 100ppm e óxido de fenbutatin a 100 e 320ppm foram inócuos a E. concordis, enquanto que endosulfan a 320ppm e dicofol a 100ppm foram inócuos a N. anonymus. Acefato, formetanate e monocrotofós, nas concentrações testadas, foram nocivos às duas espécies.Euseius concordis (Chant and Neoseiulus anonymus (Chant & Baker are predatory mites of the family Phytoseiidae commonly found on rubber trees (Hevea brasiliensis Muell. Arg. in the State of Mato Grosso, in the mid-west Brazil. This work was conducted to verify the effect of acaricides and insecticides-acaricides occasionally used in rubber tree plantations, and other products that could be used against

  20. Stable Isotopes of Nitrogen in Fossil Cladoceran Exoskeletons: Implications for Nitrogen Sources in the Central Baltic Sea During the Past Century

    Science.gov (United States)

    Struck, Ulrich; Voss, Maren; von Bodungen, Bodo; Mumm, Nicolai

    The ratios of stable nitrogen isotopes were analysed in zooplankton exoskeletons extracted from dated sediment cores from the Gotland Basin of the central Baltic Sea. Combined with results on δ15N of bulk sediment, organic carbon concentrations, and abundances of exoskeletons of Bosminalongispinamaritima in the sediment, the data are used to evaluate significant sources of nitrogen in the food web over the past century. Nitrogen isotopic composition of bulk sediments ranges from 2.5 to 4.5ö, that of exokeletons varies between 0.4 and 6.2ö. The two are positively correlated. A marked increase in the abundance of Bosmina since 1965 (from less than 500 specimen to more than 5000 specimencm3 of sediment) is correlated with a significant increase in sedimentary organic carbon concentrations (from 4% to more than 10%). The isotopic data do not identify increased land-derived nitrate as the dominant nitrogen source fuelling the increase. Instead, we postulate that nitrogen fixation by diazotrophic bacteria has been one of the larger sources of nitrogen in the Baltic Sea, as it is today.

  1. Molecular cloning of manganese superoxide dismutase gene in the cladoceran Daphnia magna: Effects of microcystin, nitrite, and cadmium on gene expression profiles

    Energy Technology Data Exchange (ETDEWEB)

    Lyu, Kai; Zhu, Xuexia; Chen, Rui [Jiangsu Key Laboratory for Biodiversity and Biotechnology, School of Biological Sciences, Nanjing Normal University, 1 Wenyuan Road, Nanjing 210023 (China); Chen, Yafen [State Key Laboratory for Lake Science and Environment, Nanjing Institute of Geography and Limnology, the Chinese Academy of Sciences, Nanjing 210008 (China); Yang, Zhou, E-mail: yangzhou@njnu.edu.cn [Jiangsu Key Laboratory for Biodiversity and Biotechnology, School of Biological Sciences, Nanjing Normal University, 1 Wenyuan Road, Nanjing 210023 (China)

    2014-03-01

    Graphical abstract: - Highlights: • Daphnia magna MnSOD (Dm-MnSOD) was identified and revealed MnSOD-family features. • The expression of Dm-MnSOD decreased with increased developmental stages. • Dm-MnSOD transcript was kinetically up-regulated by microcystin, nitrite and Cd. • Response of SOD to ubiquitous waterborne pollutants in D. magna was elucidated. • Dm-MnSOD gene is a potential biomarker indicating pollutants in the environment. - Abstract: Superoxide dismutases (SODs) are metalloenzymes that represent one important line of defense against oxidative stress produced by reactive oxygen species in aerobic organisms. Generally, waterborne pollutants caused by irregular anthropogenic activities often result in oxidative damage in aquatic organisms. The aim of this study was to molecularly characterize the manganese superoxide dismutase gene (Dm-MnSOD) in the waterflea, Daphnia magna, and evaluate the mRNA expression patterns quantified by real-time PCR after exposure to three common waterborne pollutants (microcystin-LR, nitrite, and cadmium). The results showed that the full-length Dm-MnSOD sequence consists of 954 bp nucleotides, encoding 215 amino acids, showing well-conserved domains that are required for metal binding and several common characteristics, such as two MnSOD domains. The deduced amino acid sequence of Dm-MnSOD shared over 70% similarity with homologues from Bythograea thermydron, Dromia personata, Cancer pagurus, and Scylla paramamosain. Dm-MnSOD gene expression was up-regulated in response to exposure to the three chemicals tested. The overall results indicated that Dm-MnSOD gene is an inducible gene and potential biomarker indicating these pollutants in the environment.

  2. Zooplankton communities in a large prealpine lake, Lake Constance: comparison between the Upper and the Lower Lake

    Directory of Open Access Journals (Sweden)

    Gerhard MAIER

    2005-08-01

    Full Text Available The zooplankton communities of two basins of a large lake, Lake Constance, were compared during the years 2002 and 2003. The two basins differ in morphology, physical and chemical conditions. The Upper Lake basin has a surface area of 470 km2, a mean depth of 100 and a maximum depth of 250 m; the Lower Lake basin has a surface area of 62 km2, a mean depth of only 13 and a maximum depth of 40 m. Nutrient, chlorophyll-a concentrations and mean temperatures are somewhat higher in the Lower than in the Upper Lake. Total abundance of rotifers (number per m2 lake surface was higher and rotifer development started earlier in the year in the Lower than in the Upper Lake. Total abundance of crustaceans was higher in the Upper Lake in the year 2002; in the year 2003 no difference in abundance could be detected between the lake basins, although in summer crustacean abundance was higher in the Lower than in the Upper Lake. Crustacean communities differed significantly between lake basins while there was no apparent difference in rotifer communities. In the Lower Lake small crustaceans, like Bosmina spp., Ceriodaphnia pulchella and Thermocyclops oithonoides prevailed. Abundance (number per m2 lake surface of predatory cladocerans, large daphnids and large copepods was much lower in the Lower than in the Upper Lake, in particular during the summer months. Ordination with nonmetric multidimensional scaling (NMS separated communities of both lakes along gradients that correlated with temperature and chlorophyll a concentration. Clutches of copepods were larger in the Lower than in the Upper Lake. No difference could be detected in clutch size of large daphnids between lake basins. Our results show that zooplankton communities in different basins of Lake Constance can be very different. They further suggest that the lack of large crustaceans in particular the lack of large predatory cladocerans in the Lower Lake can have negative effects on growth and

  3. New predatory cockroaches (Insecta: Blattaria: Manipulatoridae fam.n.) from the Upper Cretaceous Myanmar amber

    Science.gov (United States)

    Vršanský, Peter; Bechly, Günter

    2015-04-01

    We describe a new extinct lineage Manipulatoridae (new family) of cockroaches from the Upper Cretaceous (Cenomanian) amber of Myanmar. Manipulator modificaputis gen. et sp. n. is a morphologically unique extinct cockroach that represents the first (of a total of 29 known worldwide) cockroach family reported exclusively from the Myanmar amber. This family represents an early side branch of the stem group of Mantodea (most probably a sister group of Eadiidae within Blattaria/Corydioidea) because it has some synapomorphies with the Mantodea (including the stem group and Eadiidae). This family also retains symplesiomorphies that exclude a position in the crown group, and furthermore has unique autapomorphies that exclude a position as a direct ancestor of Mantodea. The unique adaptations such as strongly elongated extremities and freely movable head on a long neck suggest that these animals were pursuit predators. Five additional specimens (including two immatures) reported from the Myanmar amber suggest that this group was relatively rare but belonged to the indigenous and autochthonous inhabitants of the ancient amber forest of the Myanmar region.

  4. The feediIlg biology of four predatory reef fishes off the south ...

    African Journals Online (AJOL)

    The fIshing locality, depth and bait used were recorded. Neither fonnalin nor ... microscope for smaller specimens. ... tions of these measures were not used as they may compound sources ... method of Field, Clarke & Warwick (1982). Stomach ...

  5. Stickleback increase in the Baltic Sea : A thorny issue for coastal predatory fish

    NARCIS (Netherlands)

    Bergstrom, Ulf; Olsson, Jens; Casini, Michele; Eriksson, Britas Klemens; Fredriksson, Ronny; Wennhage, Hakan; Appelberg, Magnus

    2015-01-01

    In the Baltic Sea, the mesopredator three-spined stickleback (Gasterosteus aculeatus) spends a large part of its life cycle in the open sea, but reproduces in shallow coastal habitats. In coastal waters, it may occur in high abundances, is a potent predator on eggs and larvae of fish, and has been

  6. Aquaculture disturbance impacts the diet but not ecological linkages of a ubiquitous predatory fish

    Science.gov (United States)

    McPeek, Kathleen C.; McDonald, P. Sean; VanBlaricom, Glenn

    2015-01-01

    Aquaculture operations are a frequent and prominent cause of anthropogenic disturbance to marine and estuarine communities and may alter species composition and abundance. However, little is known about how such disturbances affect trophic linkages or ecosystem functions. In Puget Sound, Washington, aquaculture of the Pacific geoduck clam (Panopea generosa) is increasing and involves placing nets and polyvinyl chloride (PVC) tubes in intertidal areas to protect juvenile geoducks from predators. Initial studies of the structured phase of the farming cycle have documented limited impacts on the abundance of some species. To examine the effect of geoduck aquaculture on ecological linkages, the trophic relationships of a local ubiquitous consumer, Pacific staghorn sculpin (Leptocottus armatus), to its invertebrate prey were compared between geoduck aquaculture sites and nearby reference areas with no aquaculture. Mark-recapture data indicated that sculpin exhibit local site fidelity to cultured and reference areas. The stomach contents of sculpin and stable isotope signatures of sculpin and their prey were examined to study the trophic ecology of cultured and reference areas. Results showed that the structured phase of geoduck aquaculture initiated some changes to staghorn sculpin ecology, as reflected in sculpin diet through stomach content analysis. However, carbon and nitrogen stable isotopes revealed that the general food web function of sculpin remained unchanged. The source of carbon at the base of the food web and the trophic position of sculpin were not impacted by geoduck aquaculture. The study has important implications for geoduck aquaculture management and will inform regulatory decisions related to shellfish aquaculture policy.

  7. Global warming may disproportionately affect larger adults in a predatory coral reef fish

    KAUST Repository

    Messmer, Vanessa

    2016-11-03

    Global warming is expected to reduce body sizes of ectothermic animals. Although the underlying mechanisms of size reductions remain poorly understood, effects appear stronger at latitudinal extremes (poles and tropics) and in aquatic rather than terrestrial systems. To shed light on this phenomenon, we examined the size dependence of critical thermal maxima (CTmax) and aerobic metabolism in a commercially important tropical reef fish, the leopard coral grouper (Plectropomus leopardus) following acclimation to current-day (28.5 °C) vs. projected end-of-century (33 °C) summer temperatures for the northern Great Barrier Reef (GBR). CTmax declined from 38.3 to 37.5 °C with increasing body mass in adult fish (0.45-2.82 kg), indicating that larger individuals are more thermally sensitive than smaller conspecifics. This may be explained by a restricted capacity for large fish to increase mass-specific maximum metabolic rate (MMR) at 33 °C compared with 28.5 °C. Indeed, temperature influenced the relationship between metabolism and body mass (0.02-2.38 kg), whereby the scaling exponent for MMR increased from 0.74 ± 0.02 at 28.5 °C to 0.79 ± 0.01 at 33 °C, and the corresponding exponents for standard metabolic rate (SMR) were 0.75 ± 0.04 and 0.80 ± 0.03. The increase in metabolic scaling exponents at higher temperatures suggests that energy budgets may be disproportionately impacted in larger fish and contribute to reduced maximum adult size. Such climate-induced reductions in body size would have important ramifications for fisheries productivity, but are also likely to have knock-on effects for trophodynamics and functioning of ecosystems.

  8. Devonian rise in atmospheric oxygen correlated to the radiations of terrestrial plants and large predatory fish

    DEFF Research Database (Denmark)

    Dahl, Tais Wittchen; Hammarlund, Emma; Anbar, Ariel D.

    2010-01-01

    after the initial rise of animals and, therefore, suggesting that early metazoans evolved in a relatively low oxygen environment. This later oxygenation correlates with the diversification of vascular plants, which likely contributed to increased oxygenation through the enhanced burial of organic carbon...

  9. Aphid facultative symbionts reduce survival of the predatory lady beetle Hippodamia convergens

    Science.gov (United States)

    2014-01-01

    Background Non-essential facultative endosymbionts can provide their hosts with protection from parasites, pathogens, and predators. For example, two facultative bacterial symbionts of the pea aphid (Acyrthosiphon pisum), Serratia symbiotica and Hamiltonella defensa, protect their hosts from parasitism by two species of parasitoid wasp. Previous studies have not explored whether facultative symbionts also play a defensive role against predation in this system. We tested whether feeding on aphids harboring different facultative symbionts affected the fitness of an aphid predator, the lady beetle Hippodamia convergens. Results While these aphid faculative symbionts did not deter lady beetle feeding, they did decrease survival of lady beetle larvae. Lady beetle larvae fed a diet of aphids with facultative symbionts had significantly reduced survival from egg hatching to pupation and therefore had reduced survival to adult emergence. Additionally, lady beetle adults fed aphids with facultative symbionts were significantly heavier than those fed facultative symbiont-free aphids, though development time was not significantly different. Conclusions Aphids reproduce clonally and are often found in large groups. Thus, aphid symbionts, by reducing the fitness of the aphid predator H. convergens, may indirectly defend their hosts’ clonal descendants against predation. These findings highlight the often far-reaching effects that symbionts can have in ecological systems. PMID:24555501

  10. Methylmercury in a predatory fish (Cichla spp.) inhabiting the Brazilian Amazon

    Energy Technology Data Exchange (ETDEWEB)

    Kehrig, Helena do A [Laboratorio de Radioisotopos Eduardo Penna Franca, Instituto de Biofisica Carlos Chagas Filho, Universidade Federal do Rio de Janeiro (UFRJ), 21941-902 Rio de Janeiro (Brazil)], E-mail: kehrig@biof.ufrj.br; Howard, Bruce M. [T.H. Huxley School, Imperial College, London SW7 2BP (United Kingdom); Malm, Olaf [Laboratorio de Radioisotopos Eduardo Penna Franca, Instituto de Biofisica Carlos Chagas Filho, Universidade Federal do Rio de Janeiro (UFRJ), 21941-902 Rio de Janeiro (Brazil)

    2008-07-15

    This research tested whether limnological conditions, biological characteristics of fish and anthropogenic impacts influenced the assimilation of methylmercury into the muscle of a sedentary piscivorous fish, Cichla spp., from three rivers (Negro, Madeira, Tapajos) and two hydroelectric reservoirs (Balbina, Tucurui) within the Brazilian Amazon. Methylmercury in this fish ranged from 0.04 to 1.43 {mu}g g{sup -1} w.w. across sites. No significant differences were observed in the methylmercury concentrations between males and females, or for different morphotypes of this species. Positive correlations were found between methylmercury and fish body weight. No differences were found between the weight normalized methylmercury (MeHg) concentrations or its percent of total mercury in fish from the three rivers; weight normalized MeHg was highest in one of the two reservoirs. In Rio Tapajos, where gold mining and deforestation cause high water turbidity, fish showed the highest MeHg and concentrations were different across the four sites examined. In all sampling areas, the %MeHg was found to be higher than 70. - Cichla spp. may be considered good bioindicators of methylmercury contamination in the Amazonian ecosystem because of their integration of this pollutant over time.

  11. A novel disease affecting the predatory mite Phytoseiulus persimilis (Acari, Phytoseiidae): 1. Symptoms in adult females.

    Science.gov (United States)

    Schütte, Conny; Kleijn, Prisca W; Dicke, Marcel

    2006-01-01

    Adult female Phytoseiulus persimilis Athias-Henriot (Acari, Phytoseiidae) of one of our laboratory populations showed a lower degree of attraction to herbivore-induced plant volatiles than other laboratory populations. We hypothesized earlier that this consistent change in foraging behavior is a symptom of a disease, as it is a contagious phenomenon. Here we describe more symptoms by comparing mated females of this population (non-responding (NR) population) with mated females of other populations that are strongly attracted to herbivore-induced plant volatiles (responding populations). The most apparent characteristic of the NR population was the presence of numerous dorso-ventrally flattened females (76% of all females). These females had a normal size after mating but shrank during adulthood. Independent of their age, shrunken females did not reproduce and died a few days after shrinking. In addition to these profound differences in short term performance, females from the NR-population showed behavioral changes, including a lower degree of attraction to herbivore-induced plant volatiles, a higher tendency to leave a prey-patch and a lower predation rate. Moreover, about half of the live females of the NR-population carried birefringent dumbbell-shaped crystals in the legs whereas live females of a responding population carried crystals only in the lumen of the Malpighian tubules and the rectum. The symptom 'crystals in the legs' was correlated with low reproduction. Energy dispersive X-ray diffraction of these crystals revealed that they contain calcium and phosphorus along with carbon and oxygen. Crystals with comparable elemental compositions and the same characteristic concentric layering are well known in insects, where they are thought to play a major role in detoxification of calcium and heavy metals, and in storage of phosphorus. The fraction of predators carrying a white spot in the distal part of the opisthosoma, due to accumulation of excretory material in the rectum, was the same in both populations. Present results are discussed in the context of mite pathology and biological control.

  12. Intraguild interactions between the predatory mites Neoseiulus californicus and Phytoseiulus persimilis

    NARCIS (Netherlands)

    Cakmak, I.; Janssen, A.; Sabelis, M.W.

    2006-01-01

    Abstract. Species at the same trophic level may interact through competition for food, but can also interact through intraguild predation. Intraguild predation is widespread at the second and third trophic level and the effects may cascade down to the plant level. The effects of intraguild predation

  13. Birefringent Crystals and Abdominal Discoloration in the Predatory Mite Phytoseiulus persimilis (Acari: Phytoseiidae)

    Science.gov (United States)

    Bjørnson; Steiner; Keddie

    1997-03-01

    In response to grower complaints of poor performance of Phytoseiulus persimilis, mites from 14 commercial insectaries and research colonies were examined for pathogens. Some were found to have abdominal discolorations, manifested initially as two white stripes along the dorsal sides of the body within the Malpighian tubules. Advanced signs appeared as a large, centrally located, white spot or U-shaped discoloration in the distal opisthosoma within the rectum/anal atrium. White material often accumulated and hardened within the anus and formed a rectal plug that inhibited further excretion. Most affected mites were lethargic. Adults and immatures with abdominal discoloration contained numerous densely packed, birefringent, dumbbell-shaped entities. Though occasionally observed in the colon, they occurred most frequently within the Malpighian tubules and/or rectum and anal atrium. Dumbbells measured 2-4 &mgr;m long and contained prominent concentric rings. When observed by transmission electron microscopy, the entities lacked cellular organelles. Asymptomatic mites contained few or no such entities. Dumbbell-shaped inclusions were observed in P. persimilis from all sources examined. High levels of potassium, low levels of phosphorous and sulfur, and traces of chlorine were detected by energy-dispersive X-ray analysis. Guanine and uric acid, known nitrogenous wastes of arachnids, do not contain these elements. The chemical composition and structure indicate that the dumbbells are crystals. Both asymptomatic mites and those specimens exhibiting abdominal discoloration were examined for pathogens using light and transmission electron microscopy. Microsporidia, virus-like particles, and a rickettsia (genus Wolbachia) were observed in some mites but showed no correlation with white abdominal discoloration or associated crystal formation. Neither were pathogens always detected in symptomatic mites. Although birefringent crystals may be naturally occurring excretory products, the cause of white abdominal signs associated with crystal accumulation in P. persimilis is unknown. These signs indicate overall poor health.

  14. Bats without borders: Predators learn novel prey cues from other predatory species.

    Science.gov (United States)

    Patriquin, Krista J; Kohles, Jenna E; Page, Rachel A; Ratcliffe, John M

    2018-03-01

    Learning from others allows individuals to adapt rapidly to environmental change. Although conspecifics tend to be reliable models, heterospecifics with similar resource requirements may be suitable surrogates when conspecifics are few or unfamiliar with recent changes in resource availability. We tested whether Trachops cirrhosus , a gleaning bat that localizes prey using their mating calls, can learn about novel prey from conspecifics and the sympatric bat Lophostoma silvicolum. Specifically, we compared the rate for naïve T. cirrhosus to learn an unfamiliar tone from either a trained conspecific or heterospecific alone through trial and error or through social facilitation. T. cirrhosus learned this novel cue from L. silvicolum as quickly as from conspecifics. This is the first demonstration of social learning of a novel acoustic cue in bats and suggests that heterospecific learning may occur in nature. We propose that auditory-based social learning may help bats learn about unfamiliar prey and facilitate their adaptive radiation.

  15. Kin recognition by the predatory mite Iphiseius degenerans: discrimination among own, conspecific and heterospecific eggs

    NARCIS (Netherlands)

    Faraji, F.; Janssen, A.; van Rijn, P.C.J.; Sabelis, M.W.

    2000-01-01

    1. Kin recognition is important in many social insects, but has also been found in several nonsocial insects such as parasitoids, where it plays an important role in oviposition behaviour. In nonparasitic arthropods, however, the fitness of ovipositing females also depends on the oviposition

  16. Interactions between microbial-feeding and predatory soil fauna trigger N2O emissions

    NARCIS (Netherlands)

    Thakur, M.P.; Groenigen, van J.W.; Kuiper, I.; Deyn, de G.B.

    2014-01-01

    Recent research has shown that microbial-feeding invertebrate soil fauna species can significantly contribute to N2O emissions. However, in soil food webs microbial-feeding soil fauna interact with each other and with their predators, which affects microbial activity. To date we lack empirical tests

  17. Stable isotope evidence of food web connectivity by a top predatory ...

    African Journals Online (AJOL)

    In this study, food web connectivity within the Kowie Estuary on the south-east coast of South Africa was evidenced by the trophic behaviour of the predominantly piscivorous Argyrosomus japonicus. We examined stable isotopes of carbon (δ 13C) and nitrogen (δ 15N) in the dominant consumers (zooplankton, invertebrates ...

  18. Metal toxicity affects predatory stream invertebrates less than other functional feeding groups

    International Nuclear Information System (INIS)

    Liess, Matthias; Gerner, Nadine V.; Kefford, Ben J.

    2017-01-01

    Ecosystem effects of heavy metals need to be identified for a retrospective risk assessment, and potential impacts need to be predicted for a prospective risk assessment. In this study, we established a strong correlation between the toxic pressure of dissolved metals and invertebrate species. We compiled available data from a wide geographical range of Australian streams that were contaminated with heavy metals [mainly copper (Cu) and zinc (Zn)] and the corresponding invertebrate communities. Heavy metal toxicity is positively related to the proportion of predators within the invertebrate community, represented by the predator ratio , with an effect threshold range of 2.6 μg/L - 26 μg/L for Cu and 62 μg/L - 617 μg/L for Zn. These effect concentrations are in the ranges of the concentrations identified in model ecosystems and other field investigations and are just above the existing guideline limits. Heavy metals also affects the taxa richness negatively. Other community measures, such as the evenness, number of EPT (Ephemeroptera, Plecoptera, and Trichoptera) taxa, SPEcies At Risk (SPEAR) pesticides or SPEAR salinity were relatively poorly correlated with heavy metal toxicity in the streams. Therefore, we suggest applying the predator ratio within the community as a starting point for an indicator of the dissolved metal toxicity, the SPEAR metals . - Highlights: • Data on dissolved metals and invertebrates were compiled for a wide geographical range. • Heavy metal toxicity was strongly related to the predator ratio. • Ecologically relevant thresholds identified for Cu and Zn were above the guideline limits. - Increasing metal toxicity for Cu and Zn in streams could be related to an increasing predator ratio within the invertebrate community.

  19. Habitat or prey specialization in predatory ladybird beetles: a case study of two closely related species

    Czech Academy of Sciences Publication Activity Database

    Ferrer, A.; Dixon, Anthony F. G.; Hemptinne, J. L.

    2016-01-01

    Roč. 140, č. 3 (2016), s. 199-208 ISSN 0931-2048 R&D Projects: GA MŠk(CZ) ED1.1.00/02.0073 Institutional support: RVO:67179843 Keywords : aphids * habitat * ladybirds * prey * reproductive investment * specialization Subject RIV: EH - Ecology, Behaviour Impact factor: 1.641, year: 2016

  20. Predatory blue crabs induce stronger nonconsumptive effects in eastern oysters Crassostrea virginica than scavenging blue crabs

    Directory of Open Access Journals (Sweden)

    Avery E. Scherer

    2017-02-01

    Full Text Available By influencing critical prey traits such as foraging or habitat selection, predators can affect entire ecosystems, but the nature of cues that trigger prey reactions to predators are not well understood. Predators may scavenge to supplement their energetic needs and scavenging frequency may vary among individuals within a species due to preferences and prey availability. Yet prey reactions to consumers that are primarily scavengers versus those that are active foragers have not been investigated, even though variation in prey reactions to scavengers or predators might influence cascading nonconsumptive effects in food webs. Oysters Crassostrea virginica react to crab predators by growing stronger shells. We exposed oysters to exudates from crabs fed live oysters or fed aged oyster tissue to simulate scavenging, and to controls without crab cues. Oysters grew stronger shells when exposed to either crab exudate, but their shells were significantly stronger when crabs were fed live oysters. The stronger response to predators than scavengers could be due to inherent differences in diet cues representative of reduced risk in the presence of scavengers or to degradation of conspecific alarm cues in aged treatments, which may mask risk from potential predators subsisting by scavenging.

  1. Predatory behavior in a necrophagous bee Trigona hypogea (Hymenoptera; Apidae, Meliponini)

    Science.gov (United States)

    Mateus, Sidnei; Noll, Fernando B.

    Although most bees feed on nectar and pollen, several exceptions have been reported. The strangest of all is the habit found in some neotropical stingless bees, which have completely replaced pollen-eating by eating animal protein from corpses. For more than 20 years, it was believed that carrion was the only protein source for these bees. We report that these bees feed not only off dead animals, but on the living brood of social wasps and possibly other similar sources. Using well developed prey location and foraging behaviors, necrophagous bees discover recently abandoned wasps' nests and, within a few hours, prey upon all immatures found there.

  2. Intracapsular development and dispersal polymorphism in the predatory gastropod Ocenebra erinaceus (Linnaeus 1758)

    Science.gov (United States)

    Smith, Kathryn E.; Reed, Adam J.; Thatje, Sven

    2015-09-01

    Intraspecific polymorphism during development, such as poecilogony or dispersal polymorphism, has rarely been observed in the marine environment. The ecological advantages of this bet-hedging strategy, whereby the offspring from one species exhibit multiple developmental modes, include the potential for rapid colonization of new habitats while simultaneously achieving a degree of gene flow between populations. The muricid gastropod, Ocenebra erinaceus, is a common, shallow-water marine predator found across England and France. Historically, O. erinaceus caused significant damage to shellfisheries, but more recently it has been impacted by TBT-induced imposex. Despite the previous attention given to this species, little is known about its encapsulated development. Studying O. erinaceus egg capsules from the Solent, UK, we describe intracapsular development at 15 °C, the in situ temperature at time of oviposition. Within each capsule, all embryos developed; no nurse eggs were present. Development was categorized into eight ontogenetic stages, although not all individuals displayed every stage; embryos hatched as either swimming late-pediveliger larvae or crawling juveniles after 59-69 days, indicating dispersal polymorphism to occur in this species. Swimming late-pediveliger larvae completed metamorphosis within 72 h of hatching. As O. erinaceus continues to recover from TBT pollution, dispersal polymorphism may facilitate a rapid expansion in both population size and range. If this occurs, O. erinaceus has the potential to, once again, become a serious problem for shellfisheries around Europe.

  3. Flower-Visiting Butterflies Avoid Predatory Stimuli and Larger Resident Butterflies: Testing in a Butterfly Pavilion.

    Directory of Open Access Journals (Sweden)

    Yuya Fukano

    Full Text Available The flower-visiting behaviors of pollinator species are affected not only by flower traits but also by cues of predators and resident pollinators. There is extensive research into the effects of predator cues and resident pollinators on the flower-visiting behaviors of bee pollinators. However, there is relatively little research into their effects on butterfly pollinators probably because of the difficulty in observing a large number of butterfly pollination events. We conducted a dual choice experiment using artificial flowers under semi-natural conditions in the butterfly pavilion at Tama Zoological Park to examine the effects of the presence of a dead mantis and resident butterflies have on the flower-visiting behavior of several butterfly species. From 173 hours of recorded video, we observed 3235 visitations by 16 butterfly species. Statistical analysis showed that (1 butterflies avoided visiting flowers occupied by a dead mantis, (2 butterflies avoided resident butterflies that were larger than the visitor, and (3 butterflies showed greater avoidance of a predator when the predator was present together with the resident butterfly than when the predator was located on the opposite flower of the resident. Finally, we discuss the similarities and differences in behavioral responses of butterfly pollinators and bees.

  4. Who eats whom in a pool? A comparative study of prey selectivity by predatory aquatic insects

    Czech Academy of Sciences Publication Activity Database

    Klečka, Jan; Boukal S., David

    2012-01-01

    Roč. 7, č. 6 (2012), e37741 E-ISSN 1932-6203 Grant - others:EU Marie Curie European Reintegration Grant "AquaMod"(CZ) AquaMod to DSB (PERG04-GA-2008-239543); Grant Agency of the University of South Bohemia(CZ) GAJU 145/2010/P Institutional research plan: CEZ:AV0Z50070508 Keywords : aquatic insects Subject RIV: EH - Ecology, Behaviour Impact factor: 3.730, year: 2012 http://www.plosone.org/article/info%3Adoi%2F10.1371%2Fjournal.pone.0037741

  5. Model-Based Estimation of Collision Risks of Predatory Birds with Wind Turbines

    Directory of Open Access Journals (Sweden)

    Marcus Eichhorn

    2012-06-01

    Full Text Available The expansion of renewable energies, such as wind power, is a promising way of mitigating climate change. Because of the risk of collision with rotor blades, wind turbines have negative effects on local bird populations, particularly on raptors such as the Red Kite (Milvus milvus. Appropriate assessment tools for these effects have been lacking. To close this gap, we have developed an agent-based, spatially explicit model that simulates the foraging behavior of the Red Kite around its aerie in a landscape consisting of different land-use types. We determined the collision risk of the Red Kite with the turbine as a function of the distance between the wind turbine and the aerie and other parameters. The impact function comprises the synergistic effects of species-specific foraging behavior and landscape structure. The collision risk declines exponentially with increasing distance. The strength of this decline depends on the raptor's foraging behavior, its ability to avoid wind turbines, and the mean wind speed in the region. The collision risks, which are estimated by the simulation model, are in the range of values observed in the field. The derived impact function shows that the collision risk can be described as an aggregated function of distance between the wind turbine and the raptor's aerie. This allows an easy and rapid assessment of the ecological impacts of (existing or planned wind turbines in relation to their spatial location. Furthermore, it implies that minimum buffer zones for different landscapes can be determined in a defensible way. This modeling approach can be extended to other bird species with central-place foraging behavior. It provides a helpful tool for landscape planning aimed at minimizing the impacts of wind power on biodiversity.

  6. COMPARATIVE DEMOGRAPHICS OF A GENERALIST PREDATORY LADYBIRD ON FIVE APHID PREY: A LABORATORY STUDY

    Institute of Scientific and Technical Information of China (English)

    Omkar; AhmadPervez

    2004-01-01

    Prey driven demographic parameters of an aphidophagous ladybird, Propylea dissecta (Mulsant) were studied in attempt to answer how ladybird overcomes the problem of seasonally fluctuating food base. The ladybird reared for five generations in laboratory derived differential nutrition from five food sources (i.e. aphid species, Rhopalosiphum maidis (Fitch), Aphis craccivora Koch, Aphis gossypii Glover, Uroleucon compositae (Theobald) and Lipaphis erysimi (Kalt.)). The order of relative prey suitability was A. gossypii, A. craccivora, R. maidis, U. compositae and L.erysimi. Neonates suffered maximum mortality followed by eggs. Estimates of net reproductive rate,intrinsic rate of increase and finite rate of increase were highest (407.18, 0.2274 day-1, 1.2553 day-1) on A. gossypii and lowest (176.02, 0.1533 day-1, 1.1657 day-1) on L. erysimi. Generation time was shortest (26.43 days) on A. gossypii and longest (33.73 days) on L. erysimi. The present study thus,provides an explanation to the high incidence of P. dissecta on A. gossypii, as it experienced high intrinsic rate of increase and optimal values for related demographic parameters.

  7. Effects of Global Warming on Predatory Bugs Supported by Data Across Geographic and Seasonal Climatic Gradients

    Science.gov (United States)

    Schuldiner-Harpaz, Tarryn; Coll, Moshe

    2013-01-01

    Global warming may affect species abundance and distribution, as well as temperature-dependent morphometric traits. In this study, we first used historical data to document changes in Orius (Heteroptera: Anthocoridae) species assemblage and individual morphometric traits over the past seven decades in Israel. We then tested whether these changes could have been temperature driven by searching for similar patterns across seasonal and geographic climatic gradients in a present survey. The historical records indicated a shift in the relative abundance of dominant Orius species; the relative abundance of O. albidipennis, a desert-adapted species, increased while that of O. laevigatus decreased in recent decades by 6 and 10–15 folds, respectively. These shifts coincided with an overall increase of up to 2.1°C in mean daily temperatures over the last 25 years in Israel. Similar trends were found in contemporary data across two other climatic gradients, seasonal and geographic; O. albidipennis dominated Orius assemblages under warm conditions. Finally, specimens collected in the present survey were significantly smaller than those from the 1980’s, corresponding to significantly smaller individuals collected now during warmer than colder seasons. Taken together, results provide strong support to the hypothesis that temperature is the most likely driver of the observed shifts in species composition and body sizes because (1) historical changes in both species assemblage and body size were associated with rising temperatures in the study region over the last few decades; and (2) similar changes were observed as a result of contemporary drivers that are associated with temperature. PMID:23805249

  8. Global warming may disproportionately affect larger adults in a predatory coral reef fish.

    Science.gov (United States)

    Messmer, Vanessa; Pratchett, Morgan S; Hoey, Andrew S; Tobin, Andrew J; Coker, Darren J; Cooke, Steven J; Clark, Timothy D

    2017-06-01

    Global warming is expected to reduce body sizes of ectothermic animals. Although the underlying mechanisms of size reductions remain poorly understood, effects appear stronger at latitudinal extremes (poles and tropics) and in aquatic rather than terrestrial systems. To shed light on this phenomenon, we examined the size dependence of critical thermal maxima (CTmax) and aerobic metabolism in a commercially important tropical reef fish, the leopard coral grouper (Plectropomus leopardus) following acclimation to current-day (28.5 °C) vs. projected end-of-century (33 °C) summer temperatures for the northern Great Barrier Reef (GBR). CTmax declined from 38.3 to 37.5 °C with increasing body mass in adult fish (0.45-2.82 kg), indicating that larger individuals are more thermally sensitive than smaller conspecifics. This may be explained by a restricted capacity for large fish to increase mass-specific maximum metabolic rate (MMR) at 33 °C compared with 28.5 °C. Indeed, temperature influenced the relationship between metabolism and body mass (0.02-2.38 kg), whereby the scaling exponent for MMR increased from 0.74 ± 0.02 at 28.5 °C to 0.79 ± 0.01 at 33 °C, and the corresponding exponents for standard metabolic rate (SMR) were 0.75 ± 0.04 and 0.80 ± 0.03. The increase in metabolic scaling exponents at higher temperatures suggests that energy budgets may be disproportionately impacted in larger fish and contribute to reduced maximum adult size. Such climate-induced reductions in body size would have important ramifications for fisheries productivity, but are also likely to have knock-on effects for trophodynamics and functioning of ecosystems. © 2016 John Wiley & Sons Ltd.

  9. Entomopathogenic fungi in predatory beetles (Col: Carabidae and Staphylinidae) from agricultural fields

    DEFF Research Database (Denmark)

    Steenberg, T; Langer, V; Esbjerg, P

    1995-01-01

    Prevalence of entomopathogenic fungi was studied in overwintering ground beetles (Col.: Carabidae) and rove beetles (Col.: Staphylinidae) collected from fields of lucerne, white cabbage and white cabbage undersown with white clover. In general infection levels in adult ground beetles and rove bee...

  10. Adverse outcome pathway and risks of anticoagulant rodenticides to predatory wildlife

    Science.gov (United States)

    Rattner, Barnett A.; Lazarus, Rebecca S.; Elliott, John E.; Shore, Richard F.; van den Brink, Nico

    2014-01-01

    Despite a long history of successful use, routine application of some anticoagulant rodenticides (ARs) may be at a crossroad due to new regulatory guidelines intended to mitigate risk. An adverse outcome pathway for ARs was developed to identify information gaps and end points to assess the effectiveness of regulations. This framework describes chemical properties of ARs, established macromolecular interactions by inhibition of vitamin K epoxide reductase, cellular responses including altered clotting factor processing and coagulopathy, organ level effects such as hemorrhage, organism responses with linkages to reduced fitness and mortality, and potential consequences to predator populations. Risk assessments have led to restrictions affecting use of some second-generation ARs (SGARs) in North America. While the European regulatory community highlighted significant or unacceptable risk of ARs to nontarget wildlife, use of SGARs in most EU member states remains authorized due to public health concerns and the absence of safe alternatives. For purposes of conservation and restoration of island habitats, SGARs remain a mainstay for eradication of invasive species. There are significant data gaps related to exposure pathways, comparative species sensitivity, consequences of sublethal effects, potential hazards of greater AR residues in genetically resistant prey, effects of low-level exposure to multiple rodenticides, and quantitative data on the magnitude of nontarget wildlife mortality.

  11. A non-digging zoobenthivorous fish attracts two opportunistic predatory fish associates

    Directory of Open Access Journals (Sweden)

    Cristina Sazima

    Full Text Available Following behaviour among reef fishes involves mostly a digging nuclear species while foraging, which attracts opportunistic followers preying on the exposed organisms. The flying gurnard Dactylopterus volitans preys on benthic animals, mostly crustaceans and small fishes, scratching and probing the bottom with the inner rays of its pectoral fins. We recorded the flying gurnard being followed by two opportunistic predators, the yellow jack Caranx bartholomaei and the coney Cephalopholis fulva at Fernando de Noronha, off northeast Brazil. Albeit not actually digging the substrate, the flying gurnard acts as a nuclear species by exploring algae tufts and by its wandering near the boulders and ledges, disturbing and flushing out hidden animals which thus become available to predation.

  12. Biology and predatory attributes of a diplogasterid nematode, Fictor composticola Khan et al., 2008

    Directory of Open Access Journals (Sweden)

    Bajaj H. K.

    2015-02-01

    Full Text Available Biology of Fictor composticola has been studied on Aphelenchus avenae in vitro. It reproduces by amphimixis, embryonic development is completed in 24 - 27 h and life cycle in 3 - 4 days. Fusion of sperm and egg pronuclei occurs in the uteri. Pulsation of median oesophageal bulb and pressing of lips against egg shell is seen just prior to hatching but teeth seem to play no role in this process. No moulting occurs inside the egg shell and the first stage juvenile hatches out. Female and male undergo mating upon addition of water in the culture plates and continue to swim in copula for a considerable time. A female lays 1.6 - 4.0 eggs in 24 h while feeding upon A. radicicolus. Predation and reproduction is affected by the temperature and 25 - 35 °C is the optimum range for these phenomena. Process of feeding as recorded with a CCTV attached to a compound microscope is described. F. composticola engulfs small preys; sucks the intestinal contents while holding them or cuts the body wall of large-sized preys and then feeds on prolapsed organs. Two sexes differ in their efficiencies of predation, a female on an average kills 53 A. avenae as compared to 11 by a male in 24 h. F. composticola feeds and reproduces on mycophagous nematodes and juveniles of root- knot, cyst and citrus nematodes but does not prey upon adult nematodes having coarsely annulated cuticle. Cannibalism in this species is also observed. F. composticola and Seinura paratenuicaudata prey upon each other. Biocontrol potential of F. composticola for managing nematode problems in button mushroom and agricultural crops has also been discussed.

  13. Metabolism of periplasmic membrane-derived oligosaccharides by the predatory bacterium Bdellovibrio bacteriovorus 109J

    International Nuclear Information System (INIS)

    Ruby, E.G.; McCabe, J.B.

    1988-01-01

    Membrane-derived oligosaccharides (MDO), a class of osmotically active carbohydrates, are the major organic solutes present in the periplasm of Escherichia coli and many other gram-negative bacteria when cells are grown in a medium of low osmolarity. Analyses of growing cells of Bdellovibrio bacteriovorus, a gram-negative predator of other bacteria, have confirmed that they also synthesize a characteristic MDO-like class of oligosaccharides. The natural growth environment of bdellovibrios is the periplasm of other gram-negative bacteria. Because of this location, prey cell MDO constitute a potential source of organic nutrients for growing bdellovibrios. Using cells of E. coli whose MDO were 3 H labeled, we examined the extent to which B. bacteriovorus 109J metabolizes these prey cell components. Interestingly, there was neither significant degradation nor incorporation of prey cell MDO by bdellovibrios during the course of their intracellular growth. In fact, bdellovibrios had little capability either to degrade extracellular MDO that was made available to them or to transport glucose, the major monomeric constituent of prey cell MDO. Instead, periplasmic MDO were irreversibly lost to the extracellular environment during the period of bdellovibrio attack and penetration. Thus, although prey cell periplasmic proteins are retained, other important periplasmic components are released early in the bdellovibrio growth cycle. The loss of these MDO may aid in the destabilization of the prey cell plasma membrane, increasing the availability of cytoplasmic constituents to the periplasmic bdellovibrio

  14. Effect of canopy openness on the pressure of predatory arthropods and birds on epigeic insects

    Czech Academy of Sciences Publication Activity Database

    Šipoš, Jan; Drozdová, M.; Drozd, P.

    2012-01-01

    Roč. 7, č. 6 (2012), s. 1021-1029 ISSN 1895-104X R&D Projects: GA MŠk(CZ) ED1.1.00/02.0073; GA MŠk LC06073 Institutional research plan: CEZ:AV0Z60870520 Keywords : predation rate * weather conditions * living baits * temperate forest Subject RIV: EH - Ecology, Behaviour Impact factor: 0.818, year: 2012

  15. Earlier nesting by generalist predatory bird is associated with human responses to climate change.

    Science.gov (United States)

    Smith, Shawn H; Steenhof, Karen; McClure, Christopher J W; Heath, Julie A

    2017-01-01

    Warming temperatures cause temporal changes in growing seasons and prey abundance that drive earlier breeding by birds, especially dietary specialists within homogeneous habitat. Less is known about how generalists respond to climate-associated shifts in growing seasons or prey phenology, which may occur at different rates across land cover types. We studied whether breeding phenology of a generalist predator, the American kestrel (Falco sparverius), was associated with shifts in growing seasons and, presumably, prey abundance, in a mosaic of non-irrigated shrub/grasslands and irrigated crops/pastures. We examined the relationship between remotely-sensed normalized difference vegetation index (NDVI) and abundance of small mammals that, with insects, constitute approximately 93% of kestrel diet biomass. We used NDVI to estimate the start of the growing season (SoGS) in irrigated and non-irrigated lands from 1992 to 2015 and tested whether either estimate of annual SoGS predicted the timing of kestrel nesting. Finally, we examined relationships among irrigated SoGS, weather and crop planting. NDVI was a useful proxy for kestrel prey because it predicted small mammal abundance and past studies showed that NDVI predicts insect abundance. NDVI-estimated SoGS advanced significantly in irrigated lands (β = -1·09 ± 0·30 SE) but not in non-irrigated lands (β = -0·57 ± 0·53). Average date of kestrel nesting advanced 15 days in the past 24 years and was positively associated with the SoGS in irrigated lands, but not the SoGS in non-irrigated lands. Advanced SoGS in irrigated lands was related to earlier planting of crops after relatively warm winters, which were more common in recent years. Despite different patterns of SoGS change between land cover types, kestrel nesting phenology shifted with earlier prey availability in irrigated lands. Kestrels may preferentially track prey in irrigated lands over non-irrigated lands because of higher quality prey on irrigated lands, or earlier prey abundance may release former constraints on other selective pressures to breed early, such as seasonal declines in fecundity or competition for high-quality mates. This is one of the first examples of an association between human adaptation to climate change and shifts in breeding phenology of wildlife. © 2016 The Authors. Journal of Animal Ecology published by John Wiley & Sons Ltd on behalf of British Ecological Society.

  16. Concealed by darkness: interactions between predatory bats and nocturnally migrating songbirds illuminated by DNA sequencing

    OpenAIRE

    Ibáñez, Carlos; Popa-Lisseanu, Ana G.; Pastor-Beviá, David; García-Mudarra, Juan L.; Juste, Javier

    2016-01-01

    Recently, several species of aerial-hawking bats have been found to prey on migrating songbirds, but details on this behaviour and its relevance for bird migration are still unclear. We sequenced avian DNA in feather-containing scats of the bird-feeding bat Nyctalus lasiopterus from Spain collected during bird migration seasons. We found very high prey diversity, with 31 bird species from eight families of Passeriformes, almost all of which were nocturnally flying sub-Saharan migrants. Moreov...

  17. An exploration of predatory behaviour in cyberspace: Towards a typology of cyberstalkers

    OpenAIRE

    McFarlane, Leroy; Bocij, Paul

    2003-01-01

    Over the last few years governments, law enforcement agencies, and the media have noted increases of online harassment. Although there has been a great deal of research into 'offline stalking', at this moment in time there has been no formal research that attempts to classify cyberstalkers. This study aimed to identify a classification of cyberstalkers by interviewing victims. Twenty-four participants were interviewed and their responses logged on a 76-item Cyberstalking Incident Checklist. A...

  18. Intake of predatory fish in Amazonia is a driver of toxicological risk for susceptible exposure groups

    Directory of Open Access Journals (Sweden)

    Hacon S.S.

    2014-07-01

    Full Text Available High fish intake has marked the scenario of riparian communities in Amazon basin during the last three decades. Although efforts have been done by some national and international scientific groups to control mercury exposure in Brazilian Amazon, the problem persists. The return of artisan gold mining, the new hydroelectric power plants (with its reservoirs and the expansion of the agribusiness are some of the economic activities that may contribute to the increment of mercury load in the Amazon ecosystem with direct influence in the food chain. These changes in Amazon scenario increase complexity of environmental issue and mercury may become a threat for susceptible exposure groups. This study evaluated mercury exposure scenarios for susceptible groups around the hydroelectric plant to calculate toxicological risk before damming. During the period of 2009 to 2011, about 771 children under 16 years age and 276 female in reproductive age (from 16 to 40 years old were assessed. Besides, regular fish samples (n=1580 were collected for total mercury determination. The mercury concentration in fish ranged from 0.01 to 6.06 mg/kg. For the current scenario the toxicological risk ranged from 3.5 to 24 for mercury for the susceptible groups. Regarding the critical scenario after 3 years flooding, the area is expected to double the risk for the same group, especially for the communities downstream, which may represent a critical situation.

  19. Intake of predatory fish in Amazonia is a driver of toxicological risk for susceptible exposure groups

    OpenAIRE

    Hacon S.S.; Mourão D. S.; Oliveira B.; Silva G..P.; Freitas M. F.; Vega C.; Gonçalves R.; Mariani C.F.; Gomes N.; Souza A.V.; Bastos W.

    2014-01-01

    High fish intake has marked the scenario of riparian communities in Amazon basin during the last three decades. Although efforts have been done by some national and international scientific groups to control mercury exposure in Brazilian Amazon, the problem persists. The return of artisan gold mining, the new hydroelectric power plants (with its reservoirs) and the expansion of the agribusiness are some of the economic activities that may contribute to the increment of mercury load in the Ama...

  20. Description and developmental biology of the predatory diplogastrid Acrostichus nudicapitatus (Steiner, 1914 Massey, 1962 (Nematoda: Rhabditida

    Directory of Open Access Journals (Sweden)

    Ahlawat S.

    2016-06-01

    Full Text Available Acrostichus nudicapitatus (Steiner, 1914 Massey, 1962 is redescribed and illustrated along with observations on its developmental biology. Most morphometrics of the present population agree well with those of A. nudicapitatus (Steiner, 1914 Massey, 1962. The largely oviparous females of A. nudicapitatus lay eggs in single-celled or two-celled stage, 1.5 – 2 h after fertilization. In cultured females, the uterine tract was observed to accommodate occasionally as many as 4 – 6 eggs. The eggs are smooth-shelled, oval in shape measuring 45 – 48 x 23 – 26 μm in dimension. The pole of entry of sperm marks the posterior end of the developing embryo. The embryonation time has been recorded to be 20 – 25 h at 25 ± 2 °C. The first moult occurs inside the egg and the juvenile hatches as second stage juvenile. The gonad development follows the trends found in most rhabditids, however, three prime cells of the 12 vulval precursor cells have been observed to be involved in vulva formation.

  1. Flower-Visiting Butterflies Avoid Predatory Stimuli and Larger Resident Butterflies: Testing in a Butterfly Pavilion.

    Science.gov (United States)

    Fukano, Yuya; Tanaka, Yosuke; Farkhary, Sayed Ibrahim; Kurachi, Takuma

    2016-01-01

    The flower-visiting behaviors of pollinator species are affected not only by flower traits but also by cues of predators and resident pollinators. There is extensive research into the effects of predator cues and resident pollinators on the flower-visiting behaviors of bee pollinators. However, there is relatively little research into their effects on butterfly pollinators probably because of the difficulty in observing a large number of butterfly pollination events. We conducted a dual choice experiment using artificial flowers under semi-natural conditions in the butterfly pavilion at Tama Zoological Park to examine the effects of the presence of a dead mantis and resident butterflies have on the flower-visiting behavior of several butterfly species. From 173 hours of recorded video, we observed 3235 visitations by 16 butterfly species. Statistical analysis showed that (1) butterflies avoided visiting flowers occupied by a dead mantis, (2) butterflies avoided resident butterflies that were larger than the visitor, and (3) butterflies showed greater avoidance of a predator when the predator was present together with the resident butterfly than when the predator was located on the opposite flower of the resident. Finally, we discuss the similarities and differences in behavioral responses of butterfly pollinators and bees.

  2. Potential of predatory bacteria as biocontrol agents for foodborne and plant pathogens

    Science.gov (United States)

    Foodborne pathogens such as Escherichia coli O157:H7, Salmonella spp., Listeria monocytogenes, Shigella are responsible for frequent occurrences of illnesses and mortality in humans and produce losses. Pre-harvest yield losses and post-harvest decay on minimally processed produce (fruits, vegetables...

  3. Functional response of predatory thrips to two-spotted spider mite - influence of pesticides

    DEFF Research Database (Denmark)

    Pakyari, Hajar; Enkegaard, Annie

    2013-01-01

    A leaf disc bioassay was used to investigate the effects of abamectin and fenpropathrin on the functional response of an acarophagous thrips, Scolothrips longicornis Priesner, to eggs of Tetranychus urticae Koch at 25 ± 1°C, 60 ± 10% RH, 16:8 h (L:D). The type of the functional response differed....... The theoretical maximum number of prey attacked by the thrips was 49.67 and 23.67 eggs per day for females and males, respectively; both maxima were attained in the control treatment. These values were reduced for males exposed to full doses of either pesticide and for females exposed to both half and full doses...

  4. Digestive and locomotor capacity show opposing responses to changing food availability in an ambush predatory fish.

    Science.gov (United States)

    Fu, Shi-Jian; Peng, Jing; Killen, Shaun S

    2018-06-14

    Metabolic rates vary widely within species, but little is known about how variation in the 'floor' [i.e. standard metabolic rate (SMR) in ectotherms] and 'ceiling' [maximum metabolic rate (MMR)] for an individual's aerobic scope (AS) are linked with digestive and locomotor function. Any links among metabolic traits and aspects of physiological performance may also be modulated by fluctuations in food availability. This study followed changes in SMR, MMR, and digestive and locomotor capacity in southern catfish ( Silurus meridionalis ) throughout 15 days of food deprivation and 15 days of refeeding. Individuals downregulated SMR during food deprivation and showed only a 10% body mass decrease during this time. Whereas critical swim speed ( U crit ) was robust to food deprivation, digestive function decreased after fasting with a reduced peak oxygen uptake during specific dynamic action (SDA) and prolonged SDA duration. During refeeding, individuals displayed rapid growth and digestive function recovered to pre-fasting levels. However, refed fish showed a lower U crit than would be expected for their increased body length and in comparison to measures at the start of the study. Reduced swimming ability may be a consequence of compensatory growth: growth rate was negatively correlated with changes in U crit during refeeding. Southern catfish downregulate digestive function to reduce energy expenditure during food deprivation, but regain digestive capacity during refeeding, potentially at the cost of decreased swimming performance. The plasticity of maintenance requirements suggests that SMR is a key fitness trait for in this ambush predator. Shifts in trait correlations with food availability suggest that the potential for correlated selection may depend on context. © 2018. Published by The Company of Biologists Ltd.

  5. Global warming may disproportionately affect larger adults in a predatory coral reef fish

    KAUST Repository

    Messmer, Vanessa; Pratchett, Morgan S.; Hoey, Andrew S.; Tobin, Andrew J.; Coker, Darren James; Cooke, Steven J.; Clark, Timothy D.

    2016-01-01

    Global warming is expected to reduce body sizes of ectothermic animals. Although the underlying mechanisms of size reductions remain poorly understood, effects appear stronger at latitudinal extremes (poles and tropics) and in aquatic rather than terrestrial systems. To shed light on this phenomenon, we examined the size dependence of critical thermal maxima (CTmax) and aerobic metabolism in a commercially important tropical reef fish, the leopard coral grouper (Plectropomus leopardus) following acclimation to current-day (28.5 °C) vs. projected end-of-century (33 °C) summer temperatures for the northern Great Barrier Reef (GBR). CTmax declined from 38.3 to 37.5 °C with increasing body mass in adult fish (0.45-2.82 kg), indicating that larger individuals are more thermally sensitive than smaller conspecifics. This may be explained by a restricted capacity for large fish to increase mass-specific maximum metabolic rate (MMR) at 33 °C compared with 28.5 °C. Indeed, temperature influenced the relationship between metabolism and body mass (0.02-2.38 kg), whereby the scaling exponent for MMR increased from 0.74 ± 0.02 at 28.5 °C to 0.79 ± 0.01 at 33 °C, and the corresponding exponents for standard metabolic rate (SMR) were 0.75 ± 0.04 and 0.80 ± 0.03. The increase in metabolic scaling exponents at higher temperatures suggests that energy budgets may be disproportionately impacted in larger fish and contribute to reduced maximum adult size. Such climate-induced reductions in body size would have important ramifications for fisheries productivity, but are also likely to have knock-on effects for trophodynamics and functioning of ecosystems.

  6. Effects of insecticide exposure on movement and population size estimates of predatory ground beetles (Coleoptera: Carabidae).

    Science.gov (United States)

    Prasifka, Jarrad R; Lopez, Miriam D; Hellmich, Richard L; Prasifka, Patricia L

    2008-01-01

    Estimates of arthropod population size may paradoxically increase following insecticide applications. Research with ground beetles (Coleoptera: Carabidae) suggests that such unusual results reflect increased arthropod movement and capture in traps rather than real changes in population size. However, it is unclear whether direct (hyperactivity) or indirect (prey-mediated) mechanisms produce increased movement. Video tracking of Scarites quadriceps Chaudior indicated that brief exposure to lambda-cyhalothrin or tefluthrin increased total distance moved, maximum velocity and percentage of time moving. Repeated measurements on individual beetles indicated that movement decreased 240 min after initial lambda-cyhalothrin exposure, but increased again following a second exposure, suggesting hyperactivity could lead to increased trap captures in the field. Two field experiments in which ground beetles were collected after lambda-cyhalothrin or permethrin application attempted to detect increases in population size estimates as a result of hyperactivity. Field trials used mark-release-recapture methods in small plots and natural carabid populations in larger plots, but found no significant short-term (<6 day) increases in beetle trap captures. The disagreement between laboratory and field results suggests mechanisms other than hyperactivity may better explain unusual changes in population size estimates. When traps are used as a primary sampling tool, unexpected population-level effects should be interpreted carefully or with additional data less influenced by arthropod activity.

  7. The Anatomy of the Resource Curse: Predatory Investment in Africa’s Extractive Industries

    Science.gov (United States)

    2015-05-01

    that expose corruption and spearhead campaigns to enhance transparency and accountability. However, censorship and interference by those in power...previously served as Zimbabwe’s Acting High Commissioner in Malaysia and later sat on Zimbabwe’s Grain Marketing Board; and Pritchard Zhou, a Zimbabwean...states, reporters and nongovernmental organizations frequently face intimidation, censorship , imprisonment, and violence.420 Such policies or actions

  8. Methylmercury in a predatory fish (Cichla spp.) inhabiting the Brazilian Amazon

    International Nuclear Information System (INIS)

    Kehrig, Helena do A; Howard, Bruce M.; Malm, Olaf

    2008-01-01

    This research tested whether limnological conditions, biological characteristics of fish and anthropogenic impacts influenced the assimilation of methylmercury into the muscle of a sedentary piscivorous fish, Cichla spp., from three rivers (Negro, Madeira, Tapajos) and two hydroelectric reservoirs (Balbina, Tucurui) within the Brazilian Amazon. Methylmercury in this fish ranged from 0.04 to 1.43 μg g -1 w.w. across sites. No significant differences were observed in the methylmercury concentrations between males and females, or for different morphotypes of this species. Positive correlations were found between methylmercury and fish body weight. No differences were found between the weight normalized methylmercury (MeHg) concentrations or its percent of total mercury in fish from the three rivers; weight normalized MeHg was highest in one of the two reservoirs. In Rio Tapajos, where gold mining and deforestation cause high water turbidity, fish showed the highest MeHg and concentrations were different across the four sites examined. In all sampling areas, the %MeHg was found to be higher than 70. - Cichla spp. may be considered good bioindicators of methylmercury contamination in the Amazonian ecosystem because of their integration of this pollutant over time

  9. Pollen subsidies promote whitefly control through the numerical response of predatory mites

    NARCIS (Netherlands)

    Nomikou, M.; Sabelis, M.W.; Janssen, A.

    2010-01-01

    Several studies have shown that biological control of pests can be improved by supplying extra food to natural enemies. This increases population levels of the enemies, resulting in decreases in pest densities. In theory, however, supplying food can also have negative effects on biological control.

  10. Does fragmentation of Urtica habitats affect phytophagous and predatory insects differentially?

    Science.gov (United States)

    Zabel, Jörg; Tscharntke, Teja

    1998-09-01

    Effects of habitat fragmentation on the insect community of stinging nettle (Urtica dioica L.) were studied, using 32 natural nettle patches of different area and degree of isolation in an agricultural landscape. Habitat fragmentation reduced the species richness of Heteroptera, Auchenorrhyncha, and Coleoptera, and the abundance of populations. Habitat isolation and area reduction did not affect all insect species equally. Monophagous herbivores had a higher probability of absence from small patches than all (monophagous and polyphagous) herbivore species, and the percentage of monophagous herbivores increased with habitat area. Abundance and population variability of species were negatively correlated and could both be used as a predictor of the percentage of occupied habitats. Species richness of herbivores correlated (positively) with habitat area, while species richness of predators correlated (negatively) with habitat isolation. In logistic regressions, the probability of absence of monophagous herbivores from habitat patches could only be explained by habitat area (in 4 out of 10 species) and predator absence probability only by habitat isolation (in 3 out of 14 species). Presumably because of the instability of higher-trophic-level populations and dispersal limitation, predators were more affected by habitat isolation than herbivores, while they did not differ from herbivore populations with respect to abundance or variability. Thus increasing habitat connectivity in the agricultural landscape should primarily promote predator populations.

  11. Bio-systematics of predatory mites used for control of the coconut mite

    NARCIS (Netherlands)

    Famah Sourassou, N.

    2012-01-01

    Geografische populaties van de roofmijt N. paspalivorus, een natuurlijke vijand van de kokosnootmijt, zijn morfologisch hetzelfde, maar reproductief onverenigbaar. De vrouwtjes van elke populatie zijn in staat om te paren met mannetjes van andere populaties, maar ze leggen daarna minder eieren die

  12. Size of predatory mites and refuge entrance determine success of biological control of the coconut mite

    NARCIS (Netherlands)

    da Silva, F.R.; de Moraes, G.J.; Lesna, I.; Sato, Y.; Vasquez, C.; Hanna, R.; Sabelis, M.W.; Janssen, A.

    2016-01-01

    Predators face the challenge of accessing prey that live in sheltered habitats. The coconut mite Aceriaguerreronis Keifer (Acari: Eriophyidae) lives hidden beneath the perianth, which is appressed to the coconut fruit surface, where they feed on the meristematic tissue. Its natural enemy, the

  13. Electric Organ Discharges of Mormyrid Fish as a Possible Cue for Predatory Catfish

    Science.gov (United States)

    Hanika, S.; Kramer, B.

    During reproductive migration the electroreceptive African sharptooth catfish, Clarias gariepinus (Siluriformes), preys mainly on a weakly electric fish, the bulldog Marcusenius macrolepidotus (Mormyridae; Merron 1993). This is puzzling because the electric organ discharges of known Marcusenius species are pulses of a duration (system (optimum sensitivity, 10-30Hz Peters and Bretschneider 1981). On the recent discovery that M. macrolepidotus males emit discharges lasting approximately ten times longer than those of females (Kramer 1997a) we determined behavioral thresholds for discharges of both sexes, using synthetic playbacks of field-recorded discharges. C. gariepinus detected M. macrolepidotus male discharges down to a field gradient of 103μVpeak-peak/cm and up to a distance of 1.5m at natural field conditions. In contrast, thresholds for female discharges were not reached with our setup, and we presume the bulldogs eaten by catfish are predominantly male.

  14. Concealed by darkness: interactions between predatory bats and nocturnally migrating songbirds illuminated by DNA sequencing.

    Science.gov (United States)

    Ibáñez, Carlos; Popa-Lisseanu, Ana G; Pastor-Beviá, David; García-Mudarra, Juan L; Juste, Javier

    2016-10-01

    Recently, several species of aerial-hawking bats have been found to prey on migrating songbirds, but details on this behaviour and its relevance for bird migration are still unclear. We sequenced avian DNA in feather-containing scats of the bird-feeding bat Nyctalus lasiopterus from Spain collected during bird migration seasons. We found very high prey diversity, with 31 bird species from eight families of Passeriformes, almost all of which were nocturnally flying sub-Saharan migrants. Moreover, species using tree hollows or nest boxes in the study area during migration periods were not present in the bats' diet, indicating that birds are solely captured on the wing during night-time passage. Additional to a generalist feeding strategy, we found that bats selected medium-sized bird species, thereby assumingly optimizing their energetic cost-benefit balance and injury risk. Surprisingly, bats preyed upon birds half their own body mass. This shows that the 5% prey to predator body mass ratio traditionally assumed for aerial hunting bats does not apply to this hunting strategy or even underestimates these animals' behavioural and mechanical abilities. Considering the bats' generalist feeding strategy and their large prey size range, we suggest that nocturnal bat predation may have influenced the evolution of bird migration strategies and behaviour. © 2016 John Wiley & Sons Ltd.

  15. Predatory response of Xylocoris flavipes to bruchid pests of stored food legumes

    Science.gov (United States)

    Sharlene E. Sing; Richard T. Arbogast

    2008-01-01

    Biological control may provide an affordable and sustainable option for reducing losses to pest Bruchidae in stored food legumes, a crucial source of human dietary protein. Previous investigations have focused primarily on the role of parasitism in bruchid biological control, while the potential of generalist predators has been comparatively unexplored. The true bug...

  16. With a pinch of extra salt-Did predatory protists steal genes from their food?

    Science.gov (United States)

    Czech, Laura; Bremer, Erhard

    2018-02-01

    The cellular adjustment of Bacteria and Archaea to high-salinity habitats is well studied and has generally been classified into one of two strategies. These are to accumulate high levels either of ions (the "salt-in" strategy) or of physiologically compliant organic osmolytes, the compatible solutes (the "salt-out" strategy). Halophilic protists are ecophysiological important inhabitants of salt-stressed ecosystems because they are not only very abundant but also represent the majority of eukaryotic lineages in nature. However, their cellular osmostress responses have been largely neglected. Recent reports have now shed new light on this issue using the geographically widely distributed halophilic heterotrophic protists Halocafeteria seosinensis, Pharyngomonas kirbyi, and Schmidingerothrix salinarum as model systems. Different approaches led to the joint conclusion that these unicellular Eukarya use the salt-out strategy to cope successfully with the persistent high salinity in their habitat. They accumulate various compatible solutes, e.g., glycine betaine, myo-inositol, and ectoines. The finding of intron-containing biosynthetic genes for ectoine and hydroxyectoine, their salt stress-responsive transcription in H. seosinensis, and the production of ectoine and its import by S. salinarum come as a considerable surprise because ectoines have thus far been considered exclusive prokaryotic compatible solutes. Phylogenetic considerations of the ectoine/hydroxyectoine biosynthetic genes of H. seosinensis suggest that they have been acquired via lateral gene transfer by these bacterivorous Eukarya from ectoine/hydroxyectoine-producing food bacteria that populate the same habitat.

  17. With a pinch of extra salt—Did predatory protists steal genes from their food?

    Science.gov (United States)

    Czech, Laura

    2018-01-01

    The cellular adjustment of Bacteria and Archaea to high-salinity habitats is well studied and has generally been classified into one of two strategies. These are to accumulate high levels either of ions (the “salt-in” strategy) or of physiologically compliant organic osmolytes, the compatible solutes (the “salt-out” strategy). Halophilic protists are ecophysiological important inhabitants of salt-stressed ecosystems because they are not only very abundant but also represent the majority of eukaryotic lineages in nature. However, their cellular osmostress responses have been largely neglected. Recent reports have now shed new light on this issue using the geographically widely distributed halophilic heterotrophic protists Halocafeteria seosinensis, Pharyngomonas kirbyi, and Schmidingerothrix salinarum as model systems. Different approaches led to the joint conclusion that these unicellular Eukarya use the salt-out strategy to cope successfully with the persistent high salinity in their habitat. They accumulate various compatible solutes, e.g., glycine betaine, myo-inositol, and ectoines. The finding of intron-containing biosynthetic genes for ectoine and hydroxyectoine, their salt stress–responsive transcription in H. seosinensis, and the production of ectoine and its import by S. salinarum come as a considerable surprise because ectoines have thus far been considered exclusive prokaryotic compatible solutes. Phylogenetic considerations of the ectoine/hydroxyectoine biosynthetic genes of H. seosinensis suggest that they have been acquired via lateral gene transfer by these bacterivorous Eukarya from ectoine/hydroxyectoine-producing food bacteria that populate the same habitat. PMID:29394244

  18. Predatory Aptness of Ants Against Red Flour Beetle, Tribolium Castaneum Herbst (Tenebrionidae: Coleoptera) in Wheat Flour

    International Nuclear Information System (INIS)

    Shaheen, F.A.; Parveen, S.; Qadir, G.

    2016-01-01

    The red flour beetle (RFB), Tribolium castaneum is one of the most destructive pests of stored grains and other food products including wheat flour. Due to its severe infestation, the flour gets mouldy, turns yellowish, gets pungent odour and becomes unhealthy for human consumption. The infested samples of wheat flour by T. castaneum were collected from different localities and its culture was maintained in laboratory. Three ant species namely, Dorylus labiatus, Camponotus rufipes and Monomorium minimum were collected from forest and non-forest habitats and compared for their predation against different life stages of RFB. Results showed D. labiatus of forest habitat as an efficient pupal predator that consumed 91.66% pupae of RFB. It was significantly different from non-forest ant population and control with 73.33% and 11.66% pupal predation, respectively. C. rufipes from forest habitat showed maximum adult predation (25%), which was significantly higher than non-forest ant population and control jar with 15% and 3.33% adult predation, respectively. The forest population of M. minimum exhibited 56.66% larval predation that was significantly different from non-forest population with 41.66% larval consumption. Pupal stage was the highest vulnerable stage to the ant predation and was extremely predated by D. labiatus collected from forest habitats. The lowest predation was observed at larval stage by forest population of M. minimum (1.66%) that was significantly different from all the susceptible stages of RFB. These results indicate that ants could be used as biological control agents against RFB. (author)

  19. The Role of Militia, Predatory State Authorities, and Rogue Capital in ...

    International Development Research Centre (IDRC) Digital Library (Canada)

    The nature of the relationship between militias, rogue capital, and the state in the Horn of ... and challenge the legitimacy and accountability of state authorities. ... and adaptive water management: Innovative solutions from the Global South”.

  20. The first exposure assessment of legacy and unrestricted brominated flame retardants in predatory birds of Pakistan

    DEFF Research Database (Denmark)

    Abbasi, Naeem Akhtar; Eulaers, Igor; Jaspers, Veerle Leontina Bernard

    2017-01-01

    The exposure to legacy polybrominated diphenyl ethers (PBDEs), hexabromocyclododecanes (HBCDDs) and unrestricted 1,2-bis (2,4,6-tribromophenoxy) ethane (BTBPE), bis (2-ethylhexyl)-2,3,4,5-tetrabromophthalate (BEH-TEBP) and 2-ethylhexyl-2,3,4,5-tetrabromo-benzoate (EH-TBB) was examined in tail fea...

  1. Chilocorus renipustulatus (Coleoptera: Coccinellidae) dominates predatory ladybird assemblages on Sorbus aucuparia (Rosales: Rosaceae)

    Czech Academy of Sciences Publication Activity Database

    Kula, E.; Nedvěd, Oldřich

    2011-01-01

    Roč. 108, č. 4 (2011), s. 603-608 ISSN 1210-5759 Grant - others:Ministry of Education of the Czech Republic(CZ) VZ MSM 6215648902; Ministry of Agriculture(CZ) QH82047 Institutional research plan: CEZ:AV0Z50070508 Keywords : Coccinellidae * Chilocorus renipustulatus * scale insect Subject RIV: EH - Ecology, Behaviour Impact factor: 1.061, year: 2011 http://www.eje.cz/scripts/viewabstract.php?abstract=1659

  2. Predatory threat of harpy eagles for yellow-breasted capuchin monkeys in the Atlantic Forest.

    Science.gov (United States)

    Suscke, Priscila; Verderane, Michele; de Oliveira, Robson Santos; Delval, Irene; Fernández-Bolaños, Marcelo; Izar, Patrícia

    2017-01-01

    We describe seven encounters between different harpy eagle individuals (Harpia harpyja) and a group of yellow-breasted capuchin monkeys (Sapajus xanthosternos) in Una Biological Reserve. These interactions lasted 58 min on average. In each of those encounters, the capuchin monkeys used particular behavioral strategies against the harpy eagle that were not employed in reaction to other aerial predators. We did not observe any successful predation events, but after one of those encounters an infant disappeared from the capuchin group. As a whole, these observations indicate that the presence of harpy eagles in the group's home range increases predation risk for capuchin monkeys. The present report also suggests a reoccupation by H. harpyja of this area, as no previous recent records identify harpy eagle occurrence in Una Biological Reserve.

  3. Reassessment of the predatory effects of rainbow smelt on ciscoes in Lake Superior

    Science.gov (United States)

    Myers, Jared T.; Jones, Michael L.; Stockwell, Jason D.; Yule, Daniel L.

    2009-01-01

    Evidence from small lakes suggests that predation on larval ciscoes Coregonus artedi by nonnative rainbow smelt Osmerus mordax can lead to cisco suppression or extirpation. However, evidence from larger lakes has led to equivocal conclusions. In this study, we examine the potential predation effects of rainbow smelt in two adjacent but contrasting embayments in Lake Superior (Thunder and Black bays, Ontario). During May 2006, we sampled the ichthyoplankton, pelagic fish communities, and diet composition of rainbow smelt in both bays. Using acoustics and midwater trawling, we estimated rainbow smelt densities to be 476 ± 34/ha (mean ± SE) in Thunder Bay and 3,435 ± 460/ha in Black Bay. We used a bioenergetics model to estimate the proportion of cisco larvae consumed by rainbow smelt. Our results suggest that predation by rainbow smelt accounts for 15–52% and 37–100% of the mortality of larval ciscoes in Thunder and Black bays, respectively, depending on the predator feeding rate and the scale of predator–prey overlap. We also examined the sensitivity of past conclusions (based on 1974 field collections) to assumptions of temporal overlap between rainbow smelt and larval ciscoes and estimates of rainbow smelt abundance derived from bottom trawl samples. After adjusting these parameters to reflect current understanding, we found that the previous predation estimates may have been conservative. We conclude that rainbow smelt may have been a more important contributor to the demise and slow recovery of ciscoes in Lake Superior than previously thought.

  4. The effects of in situ turbulence on the behavior of the predatory ctenophore Mnemiopsis leidyi

    Science.gov (United States)

    Colin, S.; Bezio, N.; Costello, J.; Jaspers, C.; Gemmell, B.

    2016-02-01

    Most of our understanding of the feeding mechanics of the lobate ctenophore Mnemiopsis leidyi is based on laboratory experiments with artificially calm conditions because field conditions are seldom as calm as the laboratory. We conducted both laboratory experiments with artificial turbulence and in situ particle image velocimetry (PIV) analyses to evaluate the effects of natural turbulence on the feeding behavior of M. leidyi. We found that even the lowest levels of natural turbulence degraded the feeding current of M. leidyi beyond the tips of the oral lobes. However, both laboratory and field behavioral analyses indicate that M. leidyi alters its swimming behavior in turbulence and is capable of feeding under most turbulence conditions observed.

  5. Predatory leeches (Hirudinida) may contribute to amphibian declines in the Lassen, California.

    Science.gov (United States)

    Stead Jonathan; Karen Pope

    2010-01-01

    Researchers have documented precipitous declines in Cascades Frog (Rana cascadae) populations in the southern portion of the species' range, in the Lassen region of California. Reasons for the declines, however, have not been elucidated. In addition to common, widespread causes, an understanding of local community interactions may be necessary...

  6. How do mortgage lenders influence neighbourhood dynamics? Redlining and predatory lending

    NARCIS (Netherlands)

    Aalbers, M.B.; van Ham, M.; Manley, D.; Bailey, N.; Simpson, L.; Maclennan, D.

    2013-01-01

    Manuel Aalbers argues that the actions of mortgage lenders can play an important role in understanding the trajectories of some of the most deprived neighbourhoods in Western cities. Mortgage lenders use the notion of the neighbourhood as a means to reduce their risk or to extract profit, and as

  7. Free living astigmatid mites (Astigmatina): new taxa, rearing and use for mesostigmatid (Mesostigmata) predatory mite production

    OpenAIRE

    Marina Ferraz de Camargo Barbosa

    2016-01-01

    The cohort Astigmatina is divided in two major groups: Psoroptidia, composed mainly by feather and fur mites, and Non-psoroptidia, a dominant component of the acarofauna in ephemeral habitats. In these environments Astigmatina usually are saprophages or feed on fungi or bacteria. Astigmatina protonymphs undergo a complete reorganization of the body structure leading to the production of heteromorphic deutonymphs, generally specialized for dispersion through phoresy using arthropods and verteb...

  8. Olfactoryresponse of the predatory mite Typhlodromus pyri (Acari: Phytoseiidae) to methyl salicylate in laboratory bioassays

    Science.gov (United States)

    The response of Typhlodromus pyri, a key predator of grapevine rust mite (Calepitrimerus vitis), to MeSA was tested using a Y-tube olfactometer in laboratory bioassays. Six doses ranging from 200 to 0.002 µg of diluted MeSA were tested. Significantly higher proportions of T. pyri preferred MeSA at ...

  9. Structural-functional organization of the littoral zooplankton communities of the Kremenchutskiy reservoir

    Directory of Open Access Journals (Sweden)

    Z. Burian

    2018-03-01

    Full Text Available Purpose. To find out the present state of the structural and functional organization of the littoral zooplankton communities of the upper Kremenchuk reservoir in the area of ​​the Kaniv Nature Reserve. Methodology. The material was collected in the summer time of 2016 at six stations of the littoral zone of the upper Kremenchug reservoir. The collection and analysis were carried out using generally accepted methods. The objects of the research were representatives of three main groups of zooplankton (rotifers, cladocerans, copepods, as well as ostracods and larvae of bivalve molluscs. Statistical data processing was done in MS Excel 2013. Findings. The results of the study represent the present state and organisation of littoral zooplankton. The species richness of the littoral zooplankton of the upper Kremenchug reservoir was presented by 48 species. There are 20 species of monogonont rotifers, 18 cladocerans species and copepods – 10. The representatives of the rotifer-cladoceran complex dominated in the taxonomic composition that can be explained by the preservation of the river regime and the rheophilic conditions in this part of the reservoir. The analysis showed that according to the ecological spectrum of zooplankton groups, the representatives of the pelagic group dominated – 47.92%. As for the feeding type, the largest share was represented by the non-predatory group – 64.58%. After analyzing of the quantitative indices (density and biomass of zooplankton, it was found that they were lower than average for overgrown biotopes (112580 ± 129914 ind./m³ і 1.83 ± 2.07 g/m³ and low for open water (26160 ± 19161 ind./m³ і 0,82 ± 0,86 g/m³. Originality. The present state of structural and functional organization of the littoral zooplankton communities of the upper Kremenchug reservoir has been revealed. Practical significance. The conducted studies give the information about the structural and functional organization of the

  10. Spatial and temporal habitat partitioning by zooplankton in the Bornholm Basin (central Baltic Sea)

    DEFF Research Database (Denmark)

    Schultz, J.; Peck, M.A.; Barz, K.

    2012-01-01

    taxa (Bosmina coregoni maritima, Acartia spp., Pseudocalanus spp., Temora longicornis, Synchaeta spp.) contributed >10% to the zooplankton community composition. The appearance of cladocerans was mainly correlated with the phenology of thermocline development in the spring. The cladoceran B. coregoni...

  11. Microcystis extracts and single cells have differential impacts on the demography of cladocerans: a case study on Moina cf. micrura isolated from the Mediterranean coastal shallow lake (L'Albufera, Spain)

    NARCIS (Netherlands)

    Nandini, S.; Miracle, M. R.; Vicente, E.; Sarma, S. S. S.; Gulati, R. D.

    2017-01-01

    Cyanobacteria often have a deleterious effect on zooplankton. We hypothesized that the presence of either M. aeruginosa cells or microcystin extracts from M. aeruginosa would have a significant impact on the population growth rate, survivorship, and fecundity of Moina cf. micrura isolated from

  12. Feeding ecology of the freshwater crab Trichodactylus borellianus (Decapoda: Trichodactylidae in the floodplain of the Paraná River, southern South America

    Directory of Open Access Journals (Sweden)

    Verónica Williner

    2013-09-01

    Full Text Available Freshwater crabs are not commonly considered to be an important group in trophic webs, and this might be due to a lack of knowledge about their trophic roles in aquatic ecosystems. Trichodactylus borellianus is one of the most common and widely distributed freshwater crabs in the floodplains of the southern South American rivers. The main objective of the present study was to examine the trophic role of T. borellianus, in the floodplain of the Paraná River, and its relationships with the freshwater littoral community. The trophic spectrum of this species was characterized for both sexes and individuals of different sizes (adults and juveniles, throughout daily and seasonal cycles. Samples were collected from the aquatic vegetation of three shallow lakes. The diet composition and the feeding activity of T. borellianus were evaluated through the examination of the stomach contents and their degree of emptiness. This crab species consumed several plant and animal items, including amoebas, rotifers, oligochaetes, copepods, cladocerans, and insect larvae. Moreover, this species consumes filamentous and unicellular algae, diatoms, fungi, and macrophytic remains. The predatory habits varied with the season and time of day, and variations in the feeding activity of the juveniles and adults were detected and documented. The diversity of food items eaten by this crab suggests that its trophic role in the community as an omnivore and opportunistic predator provides a connection among several trophic levels from both aquatic and terrestrial communities.

  13. Resolution of fine biological structure including small narcomedusae across a front in the Southern California Bight

    Science.gov (United States)

    McClatchie, Sam; Cowen, Robert; Nieto, Karen; Greer, Adam; Luo, Jessica Y.; Guigand, Cedric; Demer, David; Griffith, David; Rudnick, Daniel

    2012-04-01

    We sampled a front detected by SST gradient, ocean color imagery, and a Spray glider south of San Nicolas Island in the Southern California Bight between 14 and 18 October 2010. We sampled the front with an unusually extensive array of instrumentation, including the Continuous Underway Fish Egg Sampler (CUFES), the undulating In Situ Ichthyoplankton Imaging System (ISIIS) (fitted with temperature, salinity, oxygen, and fluorescence sensors), multifrequency acoustics, a surface pelagic trawl, a bongo net, and a neuston net. We found higher fluorescence and greater cladoceran, decapod, and euphausiid densities in the front, indicating increased primary and secondary production. Mesopelagic fish were most abundant in oceanic waters to the west of the front, market squid were abundant in the front associated with higher krill and decapod densities, and jack mackerel were most common in the front and on the shoreward side of the front. Egg densities peaked to either side of the front, consistent with both offshore (for oceanic squid and mesopelagic fish) and shelf origins (for white croaker and California halibut). We discovered unusually high concentrations of predatory narcomedusae in the surface layer of the frontal zone. Potential ichthyoplankton predators were more abundant either in the front (decapods, euphausiids, and squid) or shoreward of the front (medusae, chaetognaths, and jack mackerel). For pelagic fish like sardine, which can thrive in less productive waters, the safest place to spawn would be offshore because there are fewer potential predators.

  14. OECD Guidelines for the Testing of Chemicals, Test No. 226: Predatory mite (Hypoaspis (Geolaelaps) aculeifer) reproduction test in soil

    DEFF Research Database (Denmark)

    Römbke, L. Becker, B. Dark, Th. Moser, N. Halsall, W. Powley, A. Ruf, C. Scholer, E. Smit, P. Wege, N. Zenz m.fl., J.; Krogh, Paul Henning

    2008-01-01

    This Test Guideline describes a method to assess the effects of chemical substances in soil on the reproductive output of the soil mite species Hypoaspis (Geolaelaps) aculeifer Canestrini (Acari: Laelapidae). It can be used for water soluble or insoluble substances, but not with volatile substances...... replicates for each test concentrations and six to eight control replicates, of 10 animals each, are recommended. At 20 oC, the test lasts 14 days after introducing the females, which usually allows the control offspring to reach the deutonymph stage. The number of surviving females (mortality ...% for a valid test) and the number of juveniles per test vessel (at least 50 for a valid test) are determined. The fecundity of the mites exposed to the test substance is compared to that of controls in order to determine the ECx (e.g. EC10, EC50) or the No Observed Effect Concentration (NOEC). Any observed...

  15. Use of Predatory Prokaryotes to Control Drug-Resistant Bacteria and Microbial Biofilms Associated with Burn and Wound Infections

    Science.gov (United States)

    2011-06-01

    1 standard deviation. VOL. 77, 2011 PREDATION INHIBITION BY CARBOHYDRATES 2229 inhibiting effect (Fig. 3C). Since fermentation and catabolism of...between acidification of the media and predation. No inhibi- tion of predation or medium acidification was seen when non- fermentable sugar analogs were...ecology. When we eat yogurt and cheese, for example, we are eating bacteria.” Kadouri adds that the predator bacteria he is examining are among the many

  16. Insect Seed Predators in Erythrina falcata (Fabaceae): Identification of Predatory Species and Ecological Consequences of Asynchronous Flowering.

    Science.gov (United States)

    Pereira, C M; Moura, M O; Da-Silva, P R

    2014-06-01

    Seed predation by insects exerts negative effects on plant reproduction by limiting the supply of seeds and preventing germination. Seed predators of the family Fabaceae are usually generalists, which increases the rate of predation. One strategy to minimize seed predation, developed by plants from temperate regions, is "escape in time," i.e., flowering before or after the peak of predation. For tropical species, few studies have investigated the strategies used by plants to minimize seed predation. Here, using Erythrina falcata, a tropical species of Fabaceae, we test three main hypotheses: (i) escape in time is a mechanism used by E. falcata to minimize seed predation, (ii) the predators of E. falcata seeds are generalists, and (iii) the biometric variables of the pods can influence seed predation. In order to test these hypotheses, we determined the flowering time of E. falcata, rate of seed predation, the predators insects, and biometric variables of the pods. The analyzed trees were grouped into three classes: "early," "peak," and "late" flowering. The average seed predation rates on trees in the early and late classes were 65% and 50%, respectively, and in the peak class, 80%; thus, our first hypothesis can be accepted. Three species of Lepidoptera and two of Coleoptera were found preying on E. falcata seeds. These species were observed to be generalist predators; thus, our second hypothesis can be accepted. The biometric variables of the pods cannot influence seed predation rate. The ecological consequences of asynchronous flowering on plants and insects are discussed.

  17. Agricultural intensification and de-intensification differentially affect taxonomic diversity of predatory mites, earthworms, enchytraeids, nematodes and bacteria.

    NARCIS (Netherlands)

    Postma-Blaauw, M.B.; Goede, de R.G.M.; Bloem, J.; Faber, J.H.; Brussaard, L.

    2012-01-01

    Agricultural intensification is known to impact the soil biota community. In a previous study, the impact of agricultural intensification on total abundances and functional group structure of major soil biota groups were measured. In this study we address the effects of conversion of extensively

  18. Cranial ontogenetic variation in early saurischians and the role of heterochrony in the diversification of predatory dinosaurs.

    Science.gov (United States)

    Foth, Christian; Hedrick, Brandon P; Ezcurra, Martin D

    2016-01-01

    Non-avian saurischian skulls underwent at least 165 million years of evolution and shapes varied from elongated skulls, such as in the theropod Coelophysis, to short and box-shaped skulls, such as in the sauropod Camarasaurus. A number of factors have long been considered to drive skull shape, including phylogeny, dietary preferences and functional constraints. However, heterochrony is increasingly being recognized as an important factor in dinosaur evolution. In order to quantitatively analyse the impact of heterochrony on saurischian skull shape, we analysed five ontogenetic trajectories using two-dimensional geometric morphometrics in a phylogenetic framework. This allowed for the comparative investigation of main ontogenetic shape changes and the evaluation of how heterochrony affected skull shape through both ontogenetic and phylogenetic trajectories. Using principal component analyses and multivariate regressions, it was possible to quantify different ontogenetic trajectories and evaluate them for evidence of heterochronic events allowing testing of previous hypotheses on cranial heterochrony in saurischians. We found that the skull shape of the hypothetical ancestor of Saurischia likely led to basal Sauropodomorpha through paedomorphosis, and to basal Theropoda mainly through peramorphosis. Paedomorphosis then led from Orionides to Avetheropoda, indicating that the paedomorphic trend found by previous authors in advanced coelurosaurs may extend back into the early evolution of Avetheropoda. Not only are changes in saurischian skull shape complex due to the large number of factors that affected it, but heterochrony itself is complex, with a number of possible reversals throughout non-avian saurischian evolution. In general, the sampling of complete ontogenetic trajectories including early juveniles is considerably lower than the sampling of single adult or subadult individuals, which is a major impediment to the study of heterochrony on non-avian dinosaurs. Thus, the current work represents an exploratory analysis. To better understand the cranial ontogeny and the impact of heterochrony on skull evolution in saurischians, the data set that we present here must be expanded and complemented with further sampling from future fossil discoveries, especially of juvenile individuals.

  19. Cranial ontogenetic variation in early saurischians and the role of heterochrony in the diversification of predatory dinosaurs

    Directory of Open Access Journals (Sweden)

    Christian Foth

    2016-01-01

    Full Text Available Non-avian saurischian skulls underwent at least 165 million years of evolution and shapes varied from elongated skulls, such as in the theropod Coelophysis, to short and box-shaped skulls, such as in the sauropod Camarasaurus. A number of factors have long been considered to drive skull shape, including phylogeny, dietary preferences and functional constraints. However, heterochrony is increasingly being recognized as an important factor in dinosaur evolution. In order to quantitatively analyse the impact of heterochrony on saurischian skull shape, we analysed five ontogenetic trajectories using two-dimensional geometric morphometrics in a phylogenetic framework. This allowed for the comparative investigation of main ontogenetic shape changes and the evaluation of how heterochrony affected skull shape through both ontogenetic and phylogenetic trajectories. Using principal component analyses and multivariate regressions, it was possible to quantify different ontogenetic trajectories and evaluate them for evidence of heterochronic events allowing testing of previous hypotheses on cranial heterochrony in saurischians. We found that the skull shape of the hypothetical ancestor of Saurischia likely led to basal Sauropodomorpha through paedomorphosis, and to basal Theropoda mainly through peramorphosis. Paedomorphosis then led from Orionides to Avetheropoda, indicating that the paedomorphic trend found by previous authors in advanced coelurosaurs may extend back into the early evolution of Avetheropoda. Not only are changes in saurischian skull shape complex due to the large number of factors that affected it, but heterochrony itself is complex, with a number of possible reversals throughout non-avian saurischian evolution. In general, the sampling of complete ontogenetic trajectories including early juveniles is considerably lower than the sampling of single adult or subadult individuals, which is a major impediment to the study of heterochrony on non-avian dinosaurs. Thus, the current work represents an exploratory analysis. To better understand the cranial ontogeny and the impact of heterochrony on skull evolution in saurischians, the data set that we present here must be expanded and complemented with further sampling from future fossil discoveries, especially of juvenile individuals.

  20. PREDATORY PHYTOSEIID MITES (Acari:Phytoseiidae) AS BIOINDICATORS OF STRESS IMPACT ON A FARMLAND AND BUTRESSES OF THE FARMLAND REVIVAL

    Czech Academy of Sciences Publication Activity Database

    Zacharda, Miloslav

    2001-01-01

    Roč. 20, č. 1 (2001), s. 47-56 ISSN 1335-342X Institutional research plan: CEZ:AV0Z6087904 Keywords : farmland * stress * revival Subject RIV: GF - Plant Pathology, Vermin, Weed, Plant Protection Impact factor: 0.192, year: 2001

  1. Effect of a genetically modified potato on aphids and their predatory gall midge Aphidoletes aphidimyza (Rond.) (Diptera, Cecidomyiidae)

    Czech Academy of Sciences Publication Activity Database

    Hussein, Hany; Havelka, Jan

    2005-01-01

    Roč. 15, č. 2 (2005), s. 123-127 ISSN 1110-1768 R&D Projects: GA AV ČR(CZ) IBS5007102 Institutional research plan: CEZ:AV0Z50070508 Keywords : aphid-predator-interactions * GNA * Macrosiphum eubhorbiae Subject RIV: GF - Plant Pathology, Vermin, Weed, Plant Protection

  2. Resilience in moving water: Effects of turbulence on the predatory impact of the lobate ctenophore Mnemiopsis leidyi

    DEFF Research Database (Denmark)

    Jaspers, Cornelia; Costello, John H.; Sutherland, Kelly R.

    2018-01-01

    -driven turbulence affects the feeding ecology of M. leidyi, we used a combination of approaches to quantify how naturally and laboratory generated turbulence affects the behavior, feeding processes and feeding impact of M. leidyi. Experiments using laboratory generated turbulence demonstrated that turbulence can...... and field observations suggest that the feeding process of M. leidyi is resilient to wind-driven turbulence because M. leidyi shows a behavioral response to turbulence by moving deeper in the water column. Seeking refuge in deeper waters enables M. leidyi to maintain high feeding rates even under high...

  3. Gender-specific differences in cannibalism between a laboratory strain and a field strain of a predatory mite.

    Science.gov (United States)

    Revynthi, A M; Janssen, A; Egas, M

    2018-03-01

    Many phytoseiid species, including Phytoseiulus persimilis, are known to engage in cannibalism when food is scarce and when there is no possibility to disperse. In nature adult females of P. persimilis are known to disperse when prey is locally depleted. Males, in contrast, are expected to stay and wait for potential mates to mature. During this phase, males can obtain food by cannibalizing. Therefore, we hypothesize that male P. persimilis exhibit a higher tendency to cannibalize than females. Because rearing conditions in the laboratory usually prevent dispersal, prolonged culturing may also affect cannibalistic behavior. We hypothesize that this should especially affect cannibalism by females, because they consume far more food. We tested these hypotheses by comparing males and females from two strains, one of which had been in culture for over 20 years, whereas the other was recently collected from the field. It is known that this predator can discriminate between kin and non-kin and prefers cannibalizing the latter, hence to construct lines with high relatedness we created isofemale lines of these two original strains. We subsequently tested to what extent the adult females and males of the original strains and the isofemale lines cannibalized conspecific larvae from the same strain/line in a closed system. Relatedness with the victims did not affect cannibalistic behavior, but males engaged more often in cannibalism than females, and females of the laboratory strain engaged more in cannibalism than those of the field strain, both in agreement with our ideas. We hypothesize that the difference in cannibalism between the two genders will increase when they have the alternative to disperse.

  4. A novel disease affecting the predatory mite Phytoseiulus persimilis (Acari, Phytoseiidae): 2. Disease transmission by adult females.

    Science.gov (United States)

    Schütte, Conny; Poitevin, Olivier; Negash, Tesfaye; Dicke, Marcel

    2006-01-01

    Adult female Phytoseiulus persimilis Athias-Henriot (Acari, Phytoseiidae) of one of our laboratory populations (=NR-population), show the following set of symptoms: predators shrink several days after mating, cease egg production and die several days after shrinking, show a lower degree of attraction to herbivore-induced plant volatiles and a shorter choice time in olfactometer tests, have the tendency to leave a prey patch with ample food, may carry excretory crystals in the legs, may cease prey consumption, and have a lower excretion rate. We hypothesized earlier that this characteristic syndrome, called non-responding (=NR-) syndrome, is caused by a pathogen infecting P. persimilis. To further support this hypothesis we here study several transmission modes of the factor causing the NR-syndrome. In all tests we measured size, short-term fecundity, mortality, predator position, response to plant odors and crystal location, thus including 6 of the 9 symptoms known yet. No evidence was found for vertical transmission from parent to offspring. Eggs from symptomatic females of the NR-population mated by males of the NR-population gave rise to normal-sized, well performing predators, when they had been surface sterilized or transferred to a new leaf. However, such eggs gave rise to shrunken females (17%) when left on the leaf where they had been laid. In the latter case transmission via products deposited on the leaf by the mothers was possible. We therefore tested several modes of horizontal transmission by exposing females of a commercial population that never showed the NR-syndrome (=R1-population) to products related to the symptomatic NR-population. No evidence was found for transmission via food or via squashed adult females. However, symptoms were induced in adult females of the R1-population after a 3-day exposure to a live adult female of the NR-population (incubation period=3-7 days, fraction shrunken females=53%) and after a 1-day exposure to feces and debris collected from such females (incubation period=2-4 days, fraction shrunken females=65%). Contact with live females and feces of the R1-population did not induce the syndrome. These results clearly indicate that the NR-syndrome is a contagious phenomenon and that the factor inducing the syndrome is transmitted horizontally among and between generations via feces and debris deposited by symptomatic females. The results are discussed in the context of mite pathology and biological control.

  5. Development and pathology of two undescribed species of microsporidia infecting the predatory mite, Phytoseiulus persimilis Athias-Henriot.

    Science.gov (United States)

    Bjøornson, S; Keddie, B A

    2000-11-01

    Two undescribed species of microsporidia were found in mass-reared Phytoseiulus persimilis Athias-Henriot from two commercial sources during a routine examination of these predators for pathogens. Both microsporidian species were described from specimens that had been prepared for transmission electron microscopy; live specimens were unavailable for examination. One microsporidium, identified as Species A, was described from two specimens obtained from a commercial insectary in North America. All observed stages of this microsporidium were uninucleate. Rounded-to-ovoid schizonts appeared to develop in direct contact with the cytoplasm of lyrate organ cells (ovarian tissue). Mature spores of Species A were elongate-ovoid and measured 2.88 x 1.21 microm. A polar filament coiled 7 to 10 times in the posterior half of the spore. Sporoblasts and spores were observed in the cytoplasm of cells of numerous tissues and in developing eggs within gravid females. A second species, identified as Species B, was described from five specimens obtained from a commercial source in Israel. All observed stages of this microsporidium were uninucleate. Schizonts of Species B were observed within the cytoplasm of cecal wall cells and within the nuclei of lyrate organ cells. Mature spores were ovoid and measured 2.65 x 1.21 microm. A polar filament coiled 3 to 4 times in the posterior half of the spore. Densely packed ribosomes often concealed the polar filament and other internal spore characteristics. Spores were observed in the cytoplasm of cells of numerous tissues and occasionally within the nuclei of lyrate organ cells. Numerous spores and presporal stages were observed within the ovary and developing eggs. The development and pathology of Species A and B were compared to those of Microsporidium phytoseiuli Bjøornson, Steiner and Keddie, a microsporidium previously described from P. persimilis obtained from a commercial source in Europe. The occurrence of three species of microsporidia within P. persimilis from three sources raises questions regarding the origin of these pathogens. Because microsporidia may have profound impact on the performance of P. persimilis, consideration must be given to the identification and exclusion of microsporidia from field-collected specimens or from predators that may be shared among commercial sources.

  6. Survival and behavioural responses of the predatory ladybird beetle, Eriopis connexa populations susceptible and resistant to a pyrethroid insecticide.

    Science.gov (United States)

    Spíndola, A F; Silva-Torres, C S A; Rodrigues, A R S; Torres, J B

    2013-08-01

    The ladybird beetle, Eriopis connexa (Germar) (Coleoptera: Coccinellidae), is one of the commonest predators of aphids (Hemiptera: Aphididae) in the cotton agroecosystem and in many other row and fruit crops in Brazil, and has been introduced into other countries such as the USA for purposes of aphid control. In addition, the boll weevil, Anthonomus grandis Boheman (Coleoptera: Curculionidae) is the most serious cotton pest where it occurs, including Brazil. Controlling boll weevils and other pests such as cotton defoliators still tends to involve the intense application of insecticides to secure cotton production. The pyrethroid insecticide lambda-cyhalothrin (LCT) is commonly used, but this compound is not effective against aphids; hence, a desirable strategy would be to maintain E. connexa populations in cotton fields where LCT is applied. Using populations of E. connexa resistant (Res) and susceptible (Sus) to LCT, we compared behavioural responses on treated cotton plants and under confinement on partially and fully treated surfaces, and assessed the insects' survival on treated plants compared with that of the boll weevil. The E. connexa resistant population caged on treated plants with 15 and 75 g a.i. ha-1 exhibited ≫82% survival for both insecticide concentrations compared with ≪3% and ≪17% survival for susceptible E. connexa populations and boll weevils, respectively. The response of E. connexa Res and Sus populations when released, either on the soil or on the plant canopy, indicated avoidance towards treated plants, as measured by elapsed time to assess the plant. When compared with susceptible individuals, resistant ones took longer time to suffer insecticide knockdown, had a higher recovery rate after suffering knockdown, and spent more time in the plant canopy. Based on behavioural parameters evaluated in treated arenas, no ladybird beetles exhibited repellency. However, irritability was evident, with the susceptible population exhibiting greater irritability compared with the resistant population and a subgroup comprising resistant individuals that had recovered from knockdown. The outcomes for the E. connexa Res population indicate a promising strategy for its maintenance when using the insecticide LCT in integrated pest management schemes to control boll weevil or other non-target pest of ladybird beetles in cotton fields.

  7. Carcass analysis to improve a meat-based diet for the artificial rearing of the predatory mirid bug Dicyphus tamaninii.

    Science.gov (United States)

    Zapata, Rafael; Specty, Olivier; Grenier, Simon; Febvay, Gérard; Pageaux, Jean François; Delobel, Bernard; Castañé, Cristina

    2005-10-01

    Improvement of an existing meat-based diet has been obtained for rearing the generalist predator Dicyphus tamaninii (Heteroptera: Miridae). The approach followed, different from the classical addition/deletion method, was performing biochemical analysis of adult carcasses in order to have information about the nutritional status of the predator. Comparison of total, free amino acids and lipid composition of meat-reared and conventionally reared females allowed detecting some nutritional deficiencies. A reformulated diet with new sources of proteins and lipids was tested again with the predator. Some biological parameters of bugs that were inferior in the initial meat diet when compared with those of the conventionally reared insects, such as nymphal development time and fresh weight, have been improved with the reformulated diet. (c) 2005 Wiley-Liss, Inc.

  8. High intake rates of microplastics in a Western Atlantic predatory fish, and insights of a direct fishery effect.

    Science.gov (United States)

    Ferreira, Guilherme V B; Barletta, Mário; Lima, André R A; Morley, Simon A; Justino, Anne K S; Costa, Monica F

    2018-05-01

    Microplastic contamination was investigated in the gut contents of an economically important estuarine top predator, Cynoscion acoupa, according to spatiotemporal and ontogenetic use of a tropical estuary. Microplastic contamination was found in more than half of the analysed fish. Ingested microplastics were classified by type, colour and length with most of the particles consisting of filaments (shift their feeding mode to piscivory. Moreover, the highest ingestion of filaments in adults occurred in the lower estuary, during the late rainy season, likely associated with the intense fishing activities in this habitat, which results in a greater input of filaments from fishing gear, which are mainly blue in colour. Overall, 44% of the ingested filaments were blue, 20% purple, 13% black, 10% red and 12% white. The next most common colour, the purple filaments, are most likely blue filaments whose colour has weathered to purple. Red filaments were proportionally more ingested in the lower estuary, indicating a coastal/oceanic source. White and black filaments were more commonly ingested in the inner estuary, suggesting that they have a riverine origin and/or were actively ingested by juveniles and sub-adults, which inhabit the inner estuary and have zooplankton as an important food resource. Copyright © 2018 Elsevier Ltd. All rights reserved.

  9. Changes in the selection differential exerted on a marine snail during the ontogeny of a predatory shore crab.

    Science.gov (United States)

    Pakes, D; Boulding, E G

    2010-08-01

    Empirical estimates of selection gradients caused by predators are common, yet no one has quantified how these estimates vary with predator ontogeny. We used logistic regression to investigate how selection on gastropod shell thickness changed with predator size. Only small and medium purple shore crabs (Hemigrapsus nudus) exerted a linear selection gradient for increased shell-thickness within a single population of the intertidal snail (Littorina subrotundata). The shape of the fitness function for shell thickness was confirmed to be linear for small and medium crabs but was humped for large male crabs, suggesting no directional selection. A second experiment using two prey species to amplify shell thickness differences established that the selection differential on adult snails decreased linearly as crab size increased. We observed differences in size distribution and sex ratios among three natural shore crab populations that may cause spatial and temporal variation in predator-mediated selection on local snail populations.

  10. Cold-acclimation increases the predatory efficiency of the aphidophagous coccinellid Adalia bipunctata

    DEFF Research Database (Denmark)

    Sørensen, Christian Hougaard; Toft, Søren; Kristensen, Torsten Nygård

    2013-01-01

    Ladybirds are used in integrated pest management and augmentative biological control programs all over the world. Typically, commercial rearing of the commonly used ladybird, Adalia bipunctata, takes place at a constant temperature (25 °C) which maximizes reproductive output and survival in the l...

  11. Zooplankton diversity and the predatory impact by larval and small juvenile fish at the Fisher Banks in the North Sea

    DEFF Research Database (Denmark)

    Nielsen, Torkel Gissel; Munk, Peter

    1998-01-01

    The biomass and diversity of the mesozooplankton and fish larvae community were investigated across a frontal zone in the central North Sea in the early summer, to investigate whether larval fish predation is a regulator of mesozooplankton production. Pronounced changes in the mesozooplankton com...

  12. Nonconsumptive Effects of Predatory Chrysomya rufifacies (Diptera: Calliphoridae) Larval Cues on Larval Cochliomyia macellaria (Diptera: Calliphoridae) Growth and Development.

    Science.gov (United States)

    Flores, Micah; Crippen, Tawni L; Longnecker, Michael; Tomberlin, Jeffery K

    2017-09-01

    Forensic entomologists often rely on development data associated with a given species to estimate when it colonized human or other vertebrate remains. In most instances, these development studies are based on single species reared in isolation in the laboratory. This study examined the impact of excretions and secretions (ES) associated with third-instar Chrysomya rufifacies (Macquart), a predator, on the development of its prey, Cochliomyia macellaria (F.). Not surprisingly, Ch. rufifacies ES did not impact the development of first- or second-instar C. macellaria, which are typically not preyed on by Ch. rufifacies. However, development of third-instar C. macellaria, which do experience predation, was impacted. First, larvae were longer than those in the control (deionized water, dH2O). Filtering the ES and removing the associated bacteria and byproducts >0.2 µm dampened the previous impact observed by the unfiltered ES on third-instar C. macellaria. Second, third-instar C. macellaria treated with unfiltered ES completed pupariation 8 h quicker than the controls. Filtering the ES lessened this effect by 50%. And finally, third-instar C. macellaria treated with filtered or unfiltered Ch. rufifacies ES reached adulthood ∼5 h faster than controls treated with dH2O. In summary, these data have large ramifications for forensic entomology, as multiple species being present on decomposing remains is not uncommon. Understanding the impact of associated ES produced by interspecific cohorts on associated development could lead to more precise estimates of the minimum postmortem interval for forensic investigation of decomposing remains. © The Authors 2017. Published by Oxford University Press on behalf of Entomological Society of America. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  13. Biological impacts of alcohol fuel emission on selected pollinator, predatory and nutrient-cycling insects and arachnids

    Energy Technology Data Exchange (ETDEWEB)

    D' Eliscu, P.N.

    1981-01-01

    Physiological and behavioral effects of methanol, ethanol, indolene, and formaldehyde emissions on selected arthropods are related to different relative organismic activities, metabolic rates, and respiratory demands. Various species of important pollinators, predators, and nutrient-cycling insects and arachnids respond differently to tailpipe and elevated levels of emissions. A gradient of responses is related to metabolism and trophic niche. Orders tested included various Hymenoptera, Diptera, Lepidoptera, Odonata, Orthoptera, Coleoptera, Collembola, Thysanura, Araneae, Acarina, and Opiliones. Responses included narcosis, spatial disorientation, cardiac arrhythmia, flight muscle and walking leg dysfunction, decreased feeding efficiency and prey capture success ratios, and increased positive thigmotaxis. Tolerance appears to be inversely related to oxygen demand of the arthropods tested, with active fliers most susceptible, weak fliers midscale, and non-fliers most tolerant. Electronic monitoring of heart, brain, and muscle characteristics suggests neuronal and neurosynaps disruptions from alcohols and formaldehyde, and neuromuscular effects from indolene in most arthropods tested.

  14. Infochemicals in tritrophic interactions : origin and function in a system consisting of predatory mites, phytophagous mites and their host plants

    NARCIS (Netherlands)

    Dicke, M.

    1988-01-01

    What are infochemicals?

    Chemical compounds play an important role in interactions between organisms. Some of these chemicals are to the benefit (e.g. nutrients) or detriment (e.g. toxins) of an organism. Others are of benefit or detriment in an indirect way: through the behavioural response

  15. Entomopathogenic fungi in predatory beetles (Col: Carabidae and Staphylinidae) from agricultural fields

    DEFF Research Database (Denmark)

    Steenberg, T; Langer, V; Esbjerg, P

    1995-01-01

    beetles were low (Carabidae: max. 7.6%, Staphylinidae: max. 7.0%). in comparison, prevalence of entomopathogenic fungi in carabid larvae was high (19-50%). At one study site an epizootic of Beauveria bassiana was observed, infecting 67% of staphylinid Anotylus rugosus and 37% of the staphylinid Gyrohypnus...... angustatus. Beauveria bassiana was the predominant fungus isolated from ground beetles and rove beetles from all studied sites. Other fungal species included the hyphomycetes Metarhizium anisopliae, Paecilomyces farinosus and Verticillium lecanii as well as Zoophthora radicans and Zoophthora philonthi...... (Zygomycetes: Entomophthorales). Two individuals of Anotylus rugosus were found to have a dual infection of Zoophthora philonthi and Beauveria bassiana...

  16. Insecticide susceptibility of the green plant bug, Apolygus lucorum Meyer-Dür (Homoptera: Miridae and two predatory arthropods

    Directory of Open Access Journals (Sweden)

    Zhang Zhengqun

    2015-12-01

    Full Text Available The green plant bug (Apolygus lucorum Meyer-Dür is a key pest of Bt cotton in China. Along with biological control, chemical control is one of the most important strategies in A. lucorum Integrated Pest Management (IPM. The goal of this study was to evaluate the toxicity of eight conventional insecticides to A. lucorum and to assess the susceptibility of two generalist predators Chrysopa sinica (Jieder and Propylaea japonica (Thunbery to insecticides that are commonly used in A. lucorum management. Via glass-vial and leaf-dip bioassay, toxicity tests with selected insecticides at two different life-stages of A. lucorum indicated significant differences between the LD50 or LC50 values for these compounds within different insecticidal classes. Phenylpyrazole fipronil had the highest toxicity to 4th-instar nymphs and adults of A. lucorum, whereas neonicotinoid imidacloprid had the lowest toxicity among the insecticides. Females were more tolerant to insecticides than were males, as shown by the higher LD50 values for females. Furthermore, laboratory tests showed that endosulfan had the highest selectivity to C. sinica and P. japonica: the selective toxicity ratios (STRs were superior to other tested insecticides, particularly imidacloprid, and were 5.396 and 4.749-fold higher than baseline STRs, respectively. From this study, we conclude that fipronil can potentially be used to efficiently control A. lucorum. An alternative control agent worth consideration is endosulfan, owing to its relative safety to non-targeted natural enemies.

  17. Effect of supplementary feeding of Oecophylla longinoda on their abundance and predatory activities against cashew insect pests

    DEFF Research Database (Denmark)

    Rashid Abdulla, Nassor; Rwegasira, Gration; Jensen, Karl-Martin Vagn

    2015-01-01

    Many studies have shown the efficiency of using weaver ants (Oecophylla species) as natural bio-control agents against agricultural pests. Supplementary feeding could promote fast growth of this ant's population and discourage them from moving away. However, such artificial feeding might slow down...... behaviour of O. longinoda. Fed O. longinoda colonies (FWA) were supplemented with a 30% sugar solution and approximately 22 g of finely ground fish meat at two-week intervals while the un-fed colonies (UWA) had access to only naturally occurring food sources. Weaver ant densities and pest damage...

  18. Sludge reduction by predatory activity of aquatic oligochaetes in wastewater treatment plants: Science or fiction? A review

    NARCIS (Netherlands)

    Ratsak, C.H.; Verkuijlen, J.

    2006-01-01

    Biological aerobic wastewater treatment plants (WWTPs) produce a lot of excess sludge. The costs for handling this residual product are increasing, so the search for alternative techniques to reduce the amount of sludge has to be continued. Activated sludge consists of inorganic and organic

  19. Habitat Use and Trophic Structure in a Highly Migratory Predatory Fish Identified with Geochemical Proxies in Scales

    Science.gov (United States)

    Seeley, M.; Walther, B. D.

    2016-02-01

    Atlantic tarpon, Megalops atlanticus, are highly migratory euryhaline predators that occupy different habitats throughout ontogeny. Specifically, Atlantic tarpon are known to inhabit oligohaline waters, although the frequency and duration of movements across estuarine gradients into these waters are relatively unknown. This species supports over a two billion dollar industry within the Gulf of Mexico and is currently listed as vulnerable under the International Union for the Conservation of Nature (IUCN). A new non-lethal method for reconstructing migrations across estuaries relies on trace element and stable isotope compositions of growth increments in scales. We analyzed Atlantic tarpon scales from the Texas coast to validate this method using inductively coupled plasma mass spectrometry (ICP-MS) for trace elements and isotope ratio mass spectrometry (IR-MS) for stable isotope ratios. Multiple scales were also taken from the same individual to confirm the consistency of elemental uptake within the same individual. Results show that scale Ba:Ca, Sr:Ca and δ13C are effective proxies for salinity, while enrichments in δ15N are consistent with known ontogenetic trophic shifts. In addition, chemical transects across multiple scales from the same individual were highly consistent, suggesting that any non-regenerated scale removed from a fish can provide equivalent time series. Continuous life history profiles of scales were obtained via laser ablation transects of scale cross-sections to quantify trace element concentrations from the core (youngest increments) to the edge (oldest increments). Stable isotope and trace element results together indicate that behavior is highly variable between individuals, with some but not all fish transiting estuarine gradients into oligohaline waters. Our findings will provide novel opportunities to investigate alternative non-lethal methods to monitor fish migrations across chemical gradients.

  20. Predatory Ground Beetles (Insecta: Coleoptera: Carabidae) of the Gaoligong Mountain Region of Western Yunnan Province, China: the Tribe Cyclosomini

    Science.gov (United States)

    Cueva-Dabkoski, M.; Kavanaugh, D.

    2013-12-01

    Between 1998 and 2007, the California Academy of Sciences (CAS) was the lead institution in a multi-national, multi-disciplinary biodiversity inventory project in the Gaoligong Shan region (GLGS) in the Yunnan province of China. The project surveyed the species diversity of both higher plants and bryophytes, fishes, amphibians, reptiles, birds, mammals and selected groups of arachnids and insects. The GLGS of China is one of the most biodiverse areas in all of Asia, yet it is also very poorly sampled and in great threat from increasing human activities in the region. CAS's biodiversity inventory project there has increased the number of carabid species known from just 50 to more than 550 species, an eleven-fold increase. The task that remains is to identify all of those 500 additional species and describe any that are new to science. This project is part of that larger biodiversity survey. Our objective was to identify and/or describe carabid beetles of the tribe Cyclosomini represented by nearly a hundred specimens collected in the GLSG. Among those specimens, six morphospecies were identified - one belonging to the genus Cyclosomus Latreille 1829, and the other five belonging to the genus Tetragonoderus Dejean 1829. Following this initial identification process, a list of known distributions of taxa in both genera was assembled to determine which described species to consider for comparative work. Original descriptions were then located for candidate species with known distributions in or near the GLGS; and these are being used now in morphological comparison of specimens. Type specimens for each of the candidate species have been requested from various academic institutions, and morphological comparisons with these types are underway. Morphological characteristics being examined include body proportions and overall shape, color of appendages, color and shape of pronotum, elytral color patterns, and shape and internal structure of male genitalia.

  1. Impact of artificial rearing systems on the developmental and reproductive fitness of the predatory bug, Orius laevigatus.

    Science.gov (United States)

    Bonte, Maarten; De Clercq, Patrick

    2010-01-01

    This study investigated the effect of several substrate types and moisture sources on the developmental and reproductive fitness of the zoophytophagous predator Orius laevigatus (Fieber) (Hemiptera: Anthocoridae) when fed a factitious prey (i.e. unnatural prey) Ephestia kuehniella (Zeller) eggs, or a meridic artificial diet based on hen's egg yolk. O. laevigatus is known to feed on plants as an alternative food source and to oviposit in plants. E. kuehniella eggs were superior to the artificial diet. Supplementary feeding on plant materials did not compensate for the nutritional shortcomings of the artificial diet. Survival rates showed that oviposition substrates such as bean pods or lipophilic surfaces such as wax paper and plastic were more suitable for rearing O. laevigatus than household paper. The use of green bean pods as a plant substrate did not have a beneficial effect on O. laevigatus. The results indicated that O. laevigatus can successfully complete its nymphal development and realize its full reproductive potential in the absence of plant material. However, plant materials would still be required for oviposition, unless a reliable and cost-effective artificial oviposition substrate were made available. The omission of plant materials from the rearing procedures may reduce production cost of this species and other heteropteran predators.

  2. Predatory behavior inTupinambis teguixin (Sauria: Teiidae). I. Tongue-flicking responses to chemical food stimuli.

    Science.gov (United States)

    Yanosky, A A; Iriart, D E; Mercolli, C

    1993-02-01

    Black tegu lizards (Tupinambis teguixin) have the ability to detect food odors and discriminate between them and nonfood odors. This was tested by offering chemical stimuli on cotton-tipped applicators to the animals. Stimuli were from two plant and two animal species known to be principal items in these lizards' diets, demineralized water as an odorless control, and eaude-cologne as an odorous control lacking feeding or social importance. Tongueflick attack score, latency to attack, preattack tongue-flicks, and number of attacks were analyzed. The results clearly demonstrated that this species responds to chemical food stimuli, but does not respond to odorless nonfood stimuli. Responses differed among food types. There were no sex differences. These results are in agreement with the prediction that lizards having forked tongues and an active foraging mode rely on chemical cues for feeding.

  3. Dark Side of Information Systems and Protection of Children Online: Examining Predatory Behavior and Victimization of Children within Social Media

    Science.gov (United States)

    Albert, Connie S.

    2014-01-01

    Protecting children online from sexual predators has been a focus of research in psychiatry, sociology, computer science, and information systems (IS) for many years. However, the anonymity afforded by social media has made finding a solution to the problem of child protection difficult. Pedophiles manipulate conversation (discourse) with children…

  4. Systematics of Spiny Predatory Katydids (Tettigoniidae: Listroscelidinae) from the Brazilian Atlantic Forest Based on Morphology and Molecular Data

    Science.gov (United States)

    Fialho, Verônica Saraiva; Chamorro-Rengifo, Juliana; Lopes-Andrade, Cristiano; Yotoko, Karla Suemy Clemente

    2014-01-01

    Listroscelidinae (Orthoptera: Tettigoniidae) are insectivorous Pantropical katydids whose taxonomy presents a long history of controversy, with several genera incertae sedis. This work focused on species occurring in the Brazilian Atlantic Forest, one of the world's most threatened biomes. We examined material deposited in scientific collections and visited 15 conservation units from Rio de Janeiro to southern Bahia between November 2011 and January 2012, catching 104 specimens from 10 conservation units. Based on morphological and molecular data we redefined Listroscelidini, adding a new tribe, new genus and eight new species to the subfamily. Using morphological analysis, we redescribed and added new geographic records for six species, synonymized two species and built a provisional identification key for the Atlantic Forest Listroscelidinae. Molecular results suggest two new species and a new genus to be described, possibly by the fission of the genus Hamayulus. We also proposed a 500 bp region in the final portion of the COI to be used as a molecular barcode. Our data suggest that the Atlantic Forest Listroscelidinae are seriously endangered, because they occur in highly preserved forest remnants, show high rates of endemism and have a narrow geographic distribution. Based on our results, we suggest future collection efforts must take into account the molecular barcode data to accelerate species recognition. PMID:25118712

  5. Increased control of thrips and aphids in greenhouses with two species of generalist predatory bugs involved in intraguild predation

    NARCIS (Netherlands)

    Messelink, G.J.; Janssen, A.

    2014-01-01

    The combined release of species of generalist predators can enhance multiple pest control when the predators feed on different prey, but, in theory, predators may be excluded through predation on each other. This study evaluated the co-occurrence of the generalist predators Macrolophus pygmaeus

  6. Predatory behaviour of carnivorous dinosaurs: Ecological interpretations based on tooth marked dinosaur bones and wear patterns of theropod teeth

    DEFF Research Database (Denmark)

    Jacobsen, Aase Roland

    Predation marks on bones are a source on information on the feeding behaviour of the carnivores involved. Although predator damaged bone is common in the fossil record, published reports of such marks on dinosaur bones are rare. Patterns of bone modification by mammalian carnivores overlap patterns...... left by theropod dinosaurs.Differences in tooth morphology can also be correlated with characteristics of the marks left by the teeth. In a study of tooth marks on dinosaur bones from the Dinosaur Park Formation of Alberta, Canada, it was possible to identify the feeding theropods to family, generic...... different taxa and different skeletal elements produced some interesting results. The frequency of tooth marked dinosaur bones is higher than expected. Up to 14 % of the observed hadrosaur bones were predator damaged. The lower incidence of damage in ceratopsian bones can be explained by the fact...

  7. Minimizing predatory lending: Designing a long-term compensation structure to minimize the actions of opportunistic mortgage brokers

    Directory of Open Access Journals (Sweden)

    Patrick Payne

    2013-07-01

    Full Text Available This paper addresses the inadequacies in the current compensation structure for mortgage brokers, and asserts that the resulting opportunistic behavior by brokers played a major role in the 2008 collapse of the mortgage market. We utilize agency theory as an underpinning to suggest that increased regulation will have only a limited impact on self-serving behavior due to the complex information asymmetries possessed by brokers. We posit that a restructured long-term compensation package would be effective in aligning the interests of borrowers and brokers, ultimately reducing the level of mortgage defaults and foreclosures.

  8. Experience with methyl salicylate affects behavioural responses of a predatory mite to blends of herbivore-induced plant volatiles

    NARCIS (Netherlands)

    Boer, de J.G.; Dicke, M.

    2004-01-01

    Many natural enemies of herbivorous arthropods use herbivore-induced plant volatiles to locate their prey. These foraging cues consist of mixtures of compounds that show a considerable variation within and among plantherbivore combinations, a situation that favours a flexible approach in the

  9. Information use by the predatory mite Phytoseiulus persimilis (Acari: Phytoseiidae), a specialised natural enemy of herbivorous spider mites

    NARCIS (Netherlands)

    Boer, de J.G.; Dicke, M.

    2005-01-01

    Plants can respond to infestation by herbivores with the emission of specific herbivore-induced plant volatiles. Many carnivorous arthropods that feed on herbivorous prey use these volatiles to locate their prey. Despite the growing amount of research papers on the interactions in tritrophic

  10. ISIS Child Soldiers in Syria: The Structural and Predatory Recruitment, Enlistment, Pre-Training Indoctrination, Training, and Deployment

    OpenAIRE

    Asaad Almohammad

    2018-01-01

    Research on the engagement of children with the so-called Islamic State (a.k.a. ISIS) relies heavily on the analysis of obtained ISIS documents and ISIS-disseminated propaganda, leaving major elements of the recruitment and deployment process uncovered. Such ambiguities hinder future efforts aimed at dealing with ISIS’ child soldiers. As such, an intensive effort to compile data using interviews and naturalistic observations across ISIS-held territories in Syria was made to exhaustively explo...

  11. Limnology of Eifel maar lakes

    National Research Council Canada - National Science Library

    Scharf, Burkhard W; Björk, Sven

    1992-01-01

    ... : Species composition & seasonal periodicity - Qualitative & quantitative investigations on cladoceran zooplankton of oligotrophic maar lakes - Population dynamics of pelagic copepods in maar lakes - Population dynamics...

  12. Inferring past environmental changes in three Turkish lakes from sub-fossil Cladocera

    DEFF Research Database (Denmark)

    Çakıroğlu, Ayşe İdil; Levi, Eti E.; Tavşanoğlu, Nihan

    2016-01-01

    correlated with variation in the cladoceran assemblage. Redundancy analysis showed that salinity, macrophyte abundance, fish density, depth and total phosphorus were the most correlated with change in cladoceran assemblage composition with eigenvalues for the first and the second axes being λ1 = 0.312 and λ2...... = 0.061, respectively. Sedimentary cladoceran assemblages from three cores were placed passively within the framework of the surface sediment ordination. The results reveal a prevalent impact of salinity, fish abundance and water level changes from the past to present. Thus, using cladoceran...

  13. The lake foodweb: modelling predation and abiotic/biotic interactions

    National Research Council Canada - National Science Library

    Hakanson, L; Boulion, V.V

    2002-01-01

    .... LakeWeb includes the following key functional groups of organisms: phytoplankton, bacterioplankton, benthic algae, macrophytes, zoobenthos, herbivorous and predatory zooplankton, prey fish and predatory fish...

  14. 78 FR 36134 - Limitations on Terms of Consumer Credit Extended to Service Members and Dependents

    Science.gov (United States)

    2013-06-17

    ... vigilant to eliminate continuing, evolving predatory lending practices targeting service members and their... predatory marketing practices, and other abuses identified by consumer protection advocates, including the...

  15. Population dynamics of Chaoborus flavicans and Daphnia spp.: effects on a zooplankton community in a volcanic eutrophic lake with naturally high metal concentrations (L. Monticchio Grande, Southern Italy

    Directory of Open Access Journals (Sweden)

    Letizia GARIBALDI

    2009-02-01

    Full Text Available The response of Daphnia populations to invertebrate predators involves morphological or behavioural changes. Few studies suggest that contaminant aqueous metals, like Cu or Ni at environmentally relevant concentrations, interfere with invertebrate chemical communication systems, such as that which operates between Daphnia and Chaoborus. The objective of our study was to determine if this interference could be also observed in lakes naturally rich in dissolved metals, such as volcanic lake (Lago Grande di Monticchio. This study aimed to assess if natural dissolved metals (e.g., Fe, Mn and Sr could impair the ability of Daphnia pulex and D. galeata × hyalina × cucullata 'complex' populations to respond to Chaoborus kairomones by producing morphological defenses against potential predation, and to understand how Chaoborus predation might affect zooplankton community composition and overall zooplankton density. The predator impact did not result in: i any morphological changes; ii any apparent shift in body size pattern of the prey population; iii any shift in life history traits. Chaoborus accounted for high mortality rates in Cladocera and strongly reduced the chance of individuals to reach maturity. Moreover, highly significant negative correlations between abundance of dominant taxa of zooplankton and C. flavicans were found. The last larval instars of C. flavicans seem to reduce the number of crustaceans, particularly cladocerans and copepod adults and could play an important role in structuring zooplankton communities. Our results suggest that metal inhibition of defence strategies induction probably occurs along the signal transduction pathway in Lake Grande di Monticchio. Impairment of chemosensory response to predatory chemical cues may have widespread ecological consequences in aquatic systems. Chaoborus predation effects can greatly affect both zooplankton biomass and community composition, impact interactions at lower trophic levels

  16. Spatio-temporal distribution of Diaphanosoma brachyurum (Cladocera: Sididae in freshwater reservoir ecosystems: importance of maximum water depth and macrophyte beds for avoidance of fish predation

    Directory of Open Access Journals (Sweden)

    Jong-Yun Choi

    2014-10-01

    Full Text Available In empirical studies, Cladocera is commonly utilized as a primary food source for predators such as fish, thus, predator avoidance are important strategies to sustain their population in freshwater ecosystems. In this study, we tested the hypothesis that water depth is an important factor in determining the spatial distribution of Diaphanosoma brachyurum Liévin, 1848 in response to fish predation. Quarterly monitoring was implemented at three water layers (i.e., water surface and middle and bottom layers in 21 reservoirs located in the southeastern part of South Korea. D. brachyurum individuals were frequently observed at the study sites and exhibited different spatial patterns of distribution in accordance with the maximum depth of the reservoirs. In the reservoirs with a maximum depth of more than 6 m, high densities of D. brachyurum were observed in the bottom layers; however, in the shallower reservoirs (maximum depth <6 m, D. brachyurum were concentrated in the surface layer. Moreover, during additional surveys, we observed a trend in which D. brachyurum densities increased as the maximum depth or macrophyte biomass increased. Gut contents analysis revealed that predatory fishes in each reservoir frequently consumed D. brachyurum; however, the consumption rate abruptly decreased in reservoirs where the maximum depth was more than 11 m or in the shallow reservoirs supporting a macrophyte bed. Interestingly, the reservoirs more than 11-m depth supported high densities of D. brachyurum in the bottom layer and in the surface macrophyte bed. Based on these results, reservoirs with a maximum depth of more than 11 m or those with a macrophyte bed may provide a refuge for D. brachyurum to avoid fish predation. Compared with other cladoceran species, D. brachyurum readily exploits various types of refugia (in this study, the deep layer or surface macrophyte bed, which may help explain why this species is abundant in various types of reservoirs.

  17. Fortune favours the bold: a higher predator reduces the impact of a native but not an invasive intermediate predator.

    Science.gov (United States)

    Barrios-O'Neill, Daniel; Dick, Jaimie T A; Emmerson, Mark C; Ricciardi, Anthony; MacIsaac, Hugh J; Alexander, Mhairi E; Bovy, Helene C

    2014-05-01

    Emergent multiple predator effects (MPEs) might radically alter predictions of predatory impact that are based solely on the impact of individuals. In the context of biological invasions, determining if and how the individual-level impacts of invasive predators relates to their impacts in multiple-individual situations will inform understanding of how such impacts might propagate through recipient communities. Here, we use functional responses (the relationship between prey consumption rate and prey density) to compare the impacts of the invasive freshwater mysid crustacean Hemimysis anomala with a native counterpart Mysis salemaai when feeding on basal cladoceran prey (i) as individuals, (ii) in conspecific groups and (iii) in conspecific groups in the presence of a higher fish predator, Gasterosteus aculeatus. In the absence of the higher predator, the invader consumed significantly more basal prey than the native, and consumption was additive for both mysid species - that is, group consumption was predictable from individual-level consumption. Invaders and natives were themselves equally susceptible to predation when feeding with the higher fish predator, but an MPE occurred only between the natives and higher predator, where consumption of basal prey was significantly reduced. In contrast, consumption by the invaders and higher predator remained additive. The presence of a higher predator serves to exacerbate the existing difference in individual-level consumption between invasive and native mysids. We attribute the mechanism responsible for the MPE associated with the native to a trait-mediated indirect interaction, and further suggest that the relative indifference to predator threat on the part of the invader contributes to its success and impacts within invaded communities. © 2013 The Authors. Journal of Animal Ecology © 2013 British Ecological Society.

  18. Zooplankton predators and prey: body size and stable isotope to investigate the pelagic food web in a deep lake (Lake Iseo, Northern Italy

    Directory of Open Access Journals (Sweden)

    Barbara Leoni

    2016-09-01

    Full Text Available Seasonal changes in trophic position and food sources of deep subalpine lake (Lake Iseo, Northern Italy zooplankton taxa were investigated during the year 2011. Furthermore, it's combined carbon and nitrogen Stable Isotope Analysis (SIA with size-specific analyses of both, the major predatory cladoceran (Leptodora kindtii, Focke and two potential preys (Daphnia longispina complex and Eubosmina longicornis. SIA studies have been extremely useful to track the energy flow through complex trophic network, however, if it is applied to analyze relation between two/few species may lead to misleading interpretations. In fact, integrating size-specificity allowed for understanding why L. kindtii nitrogen isotopic fingerprint fully overlapped with Daphnia, in spring. By investigating changes in L. kindtii's feeding basket, we found that in spring, L. kindtii mainly relied upon E. longicornis as prey, Daphnia being of too large body size for being captured by L. kindtii. Among preys encountered directly in front by a free-swimming Leptodora, only those able to fit into basket opening can be captured. As basket diameter increases with animal body length, size selection of prey depends on L. kindtii body length. As in other deep, subalpine lakes, E. longicornis was less 15N-enriched than Daphnia, most likely because of exploiting nitrogen fixing, cyanobacteria colonies, commonly detected in Lake Iseo with the onset of thermal stratification. Cyclopoid adults were at the top of zooplankton food chain and they could potentially be feeding on Daphnia. They, however, likely fed in a different habitat (>20 m deep water, as suggested by a rather than negligible carbon fractionation. The results overall suggest that size-specificity is crucial for addressing space and time changes in trophic links between organisms composing the two hierarchical levels within open water zooplankton community. 

  19. In-vitro predatory activity of nematophagous fungi from Costa Rica with potential use for controlling sheep and goat parasitic nematodes

    Directory of Open Access Journals (Sweden)

    Natalia Soto-Barrientos

    2011-03-01

    Full Text Available In tropical and subtropical regions of the world, parasitic diseases are a main cause of losses in livestock productivity. The increased acquired resistence to anthelmintics by gastrointestinal nematodes, requires biological control be considered as a potential feasible and effective alternative. The most effective natural soil enemies of nematodes are nematophagous fungi. In order to collect and identify predator nematophagous fungi (PNF, samples were obtained from 51 farms distributed throughout the seven provinces of Costa Rica. The origin samples included: soil from different crops (potatoes, tomatoes, bananas, ornamental plants, squash and coffee; animal feces (cattle, sheep, goat and horse; soil and fallen leaves from forest; and plants with signs of nematode infection. Each sample was processed using three techniques for the extraction of fungi from soil: sprinkling technique, soil dilution and humidity chamber. Twenty four strains of nematophagous fungi were found in 19 farms; 83.3% of the fungi were isolated by sprinkling technique. The following fungi were idenified: Arthrobotrys oligospora (n=13; Candelabrella musiformis (n=9; and for the first time there was isolation of A. conoides (n=1 and A. dactyloides (n=1 in the country. Moreover, 16 strains from Trichoderma (n=13, Beauveria (n=1, Clonostachys (n=1 and Lecanicillium (n=1 were obtained. In addition, pH of each possible fungal isolation source was measured, and it varied from 5.2 to 9.9, however PNF isolates fell within the range of 5.6 to 7.5. The PNF strains were cultivated in four different media for the production of chhlamydospores: potato dextrose agar (PDA; corn meal agar (CMA; malt extract agar (MEA and potato carrot agar (PCA. Out of these cultures, 95.8% of the strains formed chlamydospores primarily in the PCA. Of these strains, the profilic spore producers were subjected to ruminant artificial gastrointestinal conditions. A total of 14 fungi were tested, out of which 42.9% survived the digestive analysis. Neither A. conoides nor A. dactyloides were viable following the in vitro gastrointestinal test. The PNF isolated in this study demostrated an action against ovine and caprine gastrointestinal nematodes and are candidates for use in biological control of these organisms. Among these microorganisms, Candelabrella musiformis appears to be the most promising fungi for use as a biological control agent in Costa Rica. Rev. Biol. Trop. 59 (1: 37-52. Epub 2011 March 01.El control biológico es en la actualidad una alternativa para el control de los nematodos gastrointestinales que desarrollaron resistencia a los principales grupos de antihelmínticos. Para el aislamiento e identificación de hongos nematófagos depredadores, se tomaron muestras de 51 fincas distribuidas entre todas las provincias de Costa Rica. La naturaleza de las muestras incluyó: suelos de diferentes sembradíos (papa, tomate, banano, plantas ornamentales, chayote y café, heces de animales (bovinos, ovinos, caprinos y equinos, suelo y hojarasca de bosques y plantas con signos de enfermedad causada por nematodos. Las muestras se procesaron mediante 3 técnicas diferentes para la extracción de hongos a partir del suelo: espolvoreado en placa, dilución de suelos y cámara húmeda. Veinticuatro cepas de hongos nematófagos fueron aisladas de 19 fincas; el 83.3% de éstos fueron aislados mediante las técnica de espolvoreado en placa. Los hongos fueron identificados como: Arthrobotrys oligospora (n=13, Candelabrella musiformis (n=9 y por primera vez se reporta el aislamiento de A. conoides (n=1 y A. dactyloides (n=1 en el país. Asimismo, se aislaron 16 cepas de hongos de los géneros Trichoderma (n=13, Beauveria (n=1, Clonostachys (n=1 y Lecanicillium (n=1. Adicionalmente se les midió el pH, el cual varió entre 5.2-9.9, ubicándose los HND dentro de un rango entre 5.6-7.5. Las cepas de HND fueron cultivadas en 4 medios diferentes para la producción de clamidosporas: papa dextrosa agar, harina de maíz, extracto de malta y agar papa-zanahoria. El 95.8% de las cepas aisladas produjeron clamidosporas, principalmente en el medio agar papa-zanahoria. De estas cepas, se escogieron las de mayor producción para ser sometidas a la prueba de digestibilidad in vitro. Un total de 14 cepas fueron sometidos a esta prueba, de las cuales el 42.9% resultaron viables; de éstas, las cepas de A. conoides y A. dactyloides no sobrevivieron a la prueba de digestibilidad in vitro. De los microorganismos aislados, Candelabrella musiformis se considera el más promisorio de los hongos como agente biológico en Costa Rica.

  20. Comparative study of predatory responses in blue mussels (Mytilus edulis L.) produced in suspended long line cultures or collected from natural bottom mussel beds

    DEFF Research Database (Denmark)

    Christensen, Helle Torp; Dolmer, Per; Petersen, Jens Kjerulf

    2011-01-01

    Blue mussels (Mytilus edulis L.) are a valuable resource for commercial shellfish production and may also have uses as a tool in habitat improvement, because mussel beds can increase habitat diversity and complexity. A prerequisite for both commercial mussel production and habitat improvement...... originated from suspended cultures had a higher length increment and lower mortality when compared to bottom mussels. It is concluded that suspended mussels potentially are an alternative resource to bottom culture and can be used in habitat improvement of mussel beds, but that the use of suspended mussels...

  1. Anatomical Analysis of the Retinal Specializations to a Crypto-Benthic, Micro-Predatory Lifestyle in the Mediterranean Triplefin Blenny Tripterygion delaisi

    Directory of Open Access Journals (Sweden)

    Roland Fritsch

    2017-12-01

    Full Text Available The environment and lifestyle of a species are known to exert selective pressure on the visual system, often demonstrating a tight link between visual morphology and ecology. Many studies have predicted the visual requirements of a species by examining the anatomical features of the eye. However, among the vast number of studies on visual specializations in aquatic animals, only a few have focused on small benthic fishes that occupy a heterogeneous and spatially complex visual environment. This study investigates the general retinal anatomy including the topography of both the photoreceptor and ganglion cell populations and estimates the spatial resolving power (SRP of the eye of the Mediterranean triplefin Tripterygion delaisi. Retinal wholemounts were prepared to systematically and quantitatively analyze photoreceptor and retinal ganglion cell (RGC densities using design-based stereology. To further examine the retinal structure, we also used magnetic resonance imaging (MRI and histological examination of retinal cross sections. Observations of the triplefin’s eyes revealed them to be highly mobile, allowing them to view the surroundings without body movements. A rostral aphakic gap and the elliptical shape of the eye extend its visual field rostrally and allow for a rostro-caudal accommodatory axis, enabling this species to focus on prey at close range. Single and twin cones dominate the retina and are consistently arranged in one of two regular patterns, which may enhance motion detection and color vision. The retina features a prominent, dorso-temporal, convexiclivate fovea with an average density of 104,400 double and 30,800 single cones per mm2, and 81,000 RGCs per mm2. Based on photoreceptor spacing, SRP was calculated to be between 6.7 and 9.0 cycles per degree. Location and resolving power of the fovea would benefit the detection and identification of small prey in the lower frontal region of the visual field.

  2. Side Effects of Four Acaricides on the Predatory Mites of Neoseiulus californicus McGregor and Phytoseiulus persimilis Athias-Henriot (Acari: Phytoseiidae

    Directory of Open Access Journals (Sweden)

    Sibel YORULMAZ SALMAN

    2017-01-01

    Full Text Available In the present study determined the side effects of four acaricides of acequinocyl, etoxazole, bifenazate and milbemectin on the predator mites Phytoseiulus persimilis Athias-Henriot and Neoseiulus californicus McGregor. Acaricide concentrations were prepared as a two times the field application dose (2T, field application dose (T, and half of the field application dose (T/2 and were then applied on eggs, nymphs and adults of the P. persimilis and N. californicus. The side effects of the acaricidesapplied to the predator mites were determined three, five and seven days afterthe application. While all doses of acequinocyl and etoxazole showed a higher toxic effect on N.californicus eggs, it was found that bifenazate and milbemectin caused similar effects on both predator mite eggs. Furthermore, it was found that the toxic effects of acequinocyl, etoxazole, bifenazate and milbemectin on nymphs and adults of the predator miteswere high seventh day after the application. The results of the study showed that four acaracides frequently used against to pest mites, should be used more carefully in the agricultural areas.

  3. Evaluation of dry-adapted strains of the predatory mite Neoseiulus californicus for spider mite control on cucumber, strawberry and pepper.

    Science.gov (United States)

    Palevsky, E; Walzer, A; Gal, S; Schausberger, P

    2008-06-01

    The goal of this study was to evaluate spider mite control efficacy of two dry-adapted strains of Neoseiulus californicus. Performance of these strains were compared to a commercial strain of Phytoseiulus persimilis on whole cucumber, pepper and strawberry plants infested with Tetranychus urticae at 50 +/- 5% RH. Under these dry conditions predators' performance was very different on each host plant. On cucumber, spider mite suppression was not attained by any of the three predators, plants 'burnt out' within 4 weeks of spider mite infestation. On strawberry, all predators satisfactorily suppressed spider mites yet they differed in short term efficacy and persistence. Phytoseiulus persimilis suppressed the spider mites more rapidly than did the BOKU and SI N. californicus strains. Both N. californicus strains persisted longer than did P. persimilis. The BOKU strain was superior to SI in population density reached, efficacy in spider mite suppression and persistence. On pepper, in the first 2 weeks of the experiment the BOKU strain was similar to P. persimilis and more efficacious in spider mite suppression than strain SI. Four weeks into the experiment the efficacy of P. persimilis dropped dramatically and was inferior to the SI and BOKU strains. Overall, mean predator density was highest on plants harbouring the BOKU strain, lowest on plants with P. persimilis and intermediate on plants with the SI strain. Implications for biocontrol of spider mites using phytoseiid species under dry conditions are discussed.

  4. Maximum swimming speeds of sailfish and three other large marine predatory fish species based on muscle contraction time and stride length

    DEFF Research Database (Denmark)

    Svendsen, Morten Bo Søndergaard; Domenici, Paolo; Marras, Stefano

    2016-01-01

    Billfishes are considered to be among the fastest swimmers in the oceans. Previous studies have estimated maximum speed of sailfish and black marlin at around 35 m s(-1) but theoretical work on cavitation predicts that such extreme speed is unlikely. Here we investigated maximum speed of sailfish...

  5. Sequential testing scheme for the assessment of the side-effects of plant protection products on the predatory bug Orius laevigatus

    NARCIS (Netherlands)

    Veire, Van de M.; Sterk, G.; Staaij, van der M.; Ramakers, P.M.J.; Tirry, L.

    2002-01-01

    This paper describes a number of test methods, to beused in a sequential scheme, for testing the side-effects ofplant protection products on anthocorid bugs. Orius laevigatuswas used as test species. A `worst case' laboratory method wasdeveloped for evaluating the effect on mortality of the

  6. Efficacy of a long-lasting bifenthrin-treated net against horticultural pests and its compatibility with the predatory mite Amblyseius swirskii and the parasitic wasp Eretmocerus mundus.

    Science.gov (United States)

    Fernández, Maria Del Mar; Colomer, Ignacio; Medina, Pilar; Fereres, Alberto; Del Estal, Pedro; Viñuela, Elisa

    2017-08-01

    Insecticide-treated nets (ITNs) have been investigated recently for their use in agriculture. Depending on the insecticide, the hole size and the way they are produced, these nets can target different pests and therefore they could be interesting options for use in integrated pest management (IPM). As the information on their compatibility with beneficial fauna is practically negligible, in this work we have tested the compatibility of an experimental bifenthrin long-lasting insecticide-treated net (LLITN) with Amblyseius swirskii and Eretmocerus mundus, important natural enemies of whiteflies and thrips, under laboratory, semi-field and commercial greenhouse conditions. In the laboratory, the treated net was very deleterious to adults of both natural enemies, after 72 h exposure. However, in choice tests with Y-tubes, both natural enemies were neither attracted nor repelled by the treated net and no short-term mortality was detected in individuals that had crossed it. No deleterious effects on the E. mundus beneficial capacity were detected in semi-field trials. In field trials, the LLITN proved to be compatible with A. swirskii while decreasing pest densities. Bifenthrin LLITN studied could be a valuable method for reducing pest population infestations in IPM programmes while being compatible with biocontrol agents. © 2017 Society of Chemical Industry. © 2017 Society of Chemical Industry.

  7. Predicting predatory impact of juvenile invasive lionfish (Pterois volitans) on a crustacean prey using functional response analysis: effects of temperature, habitat complexity and light regimes

    KAUST Repository

    South, Josie

    2017-07-01

    The ecological implications of biotic interactions, such as predator-prey relationships, are often context-dependent. Comparative functional responses analysis can be used under different abiotic contexts to improve understanding and prediction of the ecological impact of invasive species. Pterois volitans (Lionfish) [Linnaeus 1758] is an established invasive species in the Caribbean and Gulf of Mexico, with a more recent invasion into the Mediterranean. Lionfish are generalist predators that impact a wide range of commercial and non-commercial species. Functional response analysis was employed to quantify interaction strength between lionfish and a generic prey species, the shrimp (Paleomonetes varians) [Leach 1814], under the contexts of differing temperature, habitat complexity and light wavelength. Lionfish have prey population destabilising Type II functional responses under all contexts examined. Significantly more prey were consumed at 26 °C than at 22 °C. Habitat complexity did not significantly alter the functional response parameters. Significantly more prey were consumed under white light and blue light than under red light. Attack rate was significantly higher under white light than under blue or red light. Light wavelength did not significantly change handling times. The impacts on prey populations through feeding rates may increase with concomitant temperature increase. As attack rates are very high at low habitat complexity this may elucidate the cause of high impact upon degraded reef ecosystems with low-density prey populations, although there was little protection conferred through habitat complexity. Only red light (i.e. dark) afforded any reduction in predation pressure. Management initiatives should account for these environmental factors when planning mitigation and prevention strategies.

  8. A gastric evacuation model for three predatory gadoids and implications of using pooled field data of stomach contents to estimate food rations

    DEFF Research Database (Denmark)

    Andersen, Niels Gerner

    2001-01-01

    evacuation rate was related by a negative power function to energy density of fish prey,) er an extended range from 3(.)4 to 11(.)5 kJ g (1) of the effector variable. Gastric evacuation of crustacean prey seemed to depend on the characteristics of their exoskeleton, Gastric evacuation of mixed meal, composed...

  9. Validation report – Results of an International Ring test According to the Draft Guideline: Predatory mite reproduction test in soil (Hypoaspis (Geolaelaps) aculeifer) (med bidrag)

    DEFF Research Database (Denmark)

    Römbke, Jörg; Becker, B. Dark, Th. Moser, N. Halsall, W. Powley, A. Ruf, C. Scholer, E. Smit, P. Wege, N. Zenz, L.; Krogh, Paul Henning

    A new Test Guideline has been developed, which is designed to be used for assessing the effects of chemical substances in soil on the reproductive output of the soil mite species Hypoaspis (Geolaelaps) aculeifer Canestrini (Acari: Laelapidae). H. aculeifer represents an additional trophic level...... to the species for which guidelines are already available. The main endpoint is the reproduction of the mites without discrimination and quantification of the different stages of the reproductive cycle. Based on already standardised OECD and ISO test guidelines as well as ideas from literature, the ad...... caused by the ring test experiences. The results determined in the ring test proved the suitability of the proposed test method. The LC50 values for both test chemicals differed by less than a factor of 2.5 from the mean and no statistically significant differences were found between laboratories.The EC...

  10. Interactions among the predatory midge Aphidoletes aphidimyza (Diptera: Cecidomyiidae), the fungal pathogen Metarhizium brunneum (Ascomycota: Hypocreales), and maize-infesting aphids in greenhouse mesocosms

    DEFF Research Database (Denmark)

    Campos de Azevedo, Ana Gorete; Steinwender, Bernhardt Michael; Eilenberg, Jørgen

    2017-01-01

    , the interaction between these two biological control organisms and how it may affect the biological control of aphids awaits further investigation. As part of the EU-supported project INBIOSOIL, this study was conducted in greenhouse conditions to assess the possible effects of combining both biological control...... by treatment. Aphidoletes aphidimyza applied alone suppressed the aphid population more effectively than M. brunneum applied alone. Additionally, the aphid population was most suppressed when both agents were combined, though the suppression was less than additive....

  11. Bioaccumulation of cadmium in an experimental aquatic food chain involving phytoplankton (Chlorella vulgaris), zooplankton (Moina macrocopa), and the predatory catfish Clarias macrocephalus x C. gariepinus

    International Nuclear Information System (INIS)

    Ruangsomboon, Suneerat; Wongrat, Ladda

    2006-01-01

    The accumulation of cadmium (Cd) was studied in an experimental aquatic food chain involving the phytoplankton Chlorella vulgaris as the primary producer, the zooplankton Moina macrocopa as the primary consumer, and the catfish Clarias macrocephalus x Clarias gariepinus as the secondary consumer. C. vulgaris was first exposed to Cd solutions at 0.00, 0.35, and 3.50 mg l -1 , referred to as control group and experimental groups 1 and 2, respectively. Subsequently, each group was fed to three corresponding groups of M. macrocopa. Finally, three groups of catfish were fed these corresponding groups of M. macrocopa. After C. vulgaris was exposed to 3.50 mg l -1 Cd (experimental group 2), the residual Cd in solution was only 4.01 μg l -1 , lower than the maximum allowable limit of Cd in natural water sources (5 μg l -1 ). Cd concentrations in C. vulgaris were 0.01 ± 0.00 μg g -1 (dry wt) in the control group, 194 ± 1.80 μg g -1 (dry wt) in experimental group 1, and 1140 ± 20.06 μg g -1 (dry wt) in experimental group 2. The Cd concentrations in M. macrocopa were 0.01 ± 0.00 μg g -1 (dry wt) in the control group, 16.48 ± 2.23 μg g -1 (dry wt) in experimental group 1, and 56.6 ± 3.23 μg g -1 (dry wt) in experimental group 2. The Cd concentrations in catfish muscle increased with increasing Cd concentrations in the food. After 60 days of fish culture, the mean concentrations of Cd in fish muscle were 0.01 ± 0.00 μg g -1 (dry wt) in the control group, 0.61 ± 0.02 μg g -1 (dry wt) in experimental group 1 and 1.04 ± 0.06 μg g -1 (dry wt) in experimental group 2. Cd concentration in fish muscle of experimental group 2 was equal to the permissible limit. Cd accumulation affected fish growth: at the end of the study, the mean fresh weight (12.81 g) of catfish in the control group, was significantly higher than those experimental group 1 (10.43 g) and experimental group 2 (10.00 g). The results showed that the measurement of Cd concentration in water does not necessarily give a measure of the safety of aquatic organisms as human food. Hence, heavy metal contamination is a matter for concern when organisms are harvested, for fish and human consumption, from natural water sources

  12. Bioaccumulation of cadmium in an experimental aquatic food chain involving phytoplankton (Chlorella vulgaris), zooplankton (Moina macrocopa), and the predatory catfish Clarias macrocephalus x C. gariepinus

    Energy Technology Data Exchange (ETDEWEB)

    Ruangsomboon, Suneerat [Faculty of Agricultural Technology, King Mongkut' s Institute of Technology Ladkrabang, Chalongkrung Road, Bangkok 10520 (Thailand)]. E-mail: krsuneer@kmitl.ac.th; Wongrat, Ladda [Faculty of Fishery, Kasetsart University, Bangkok 10900 (Thailand)

    2006-06-10

    The accumulation of cadmium (Cd) was studied in an experimental aquatic food chain involving the phytoplankton Chlorella vulgaris as the primary producer, the zooplankton Moina macrocopa as the primary consumer, and the catfish Clarias macrocephalus x Clarias gariepinus as the secondary consumer. C. vulgaris was first exposed to Cd solutions at 0.00, 0.35, and 3.50 mg l{sup -1}, referred to as control group and experimental groups 1 and 2, respectively. Subsequently, each group was fed to three corresponding groups of M. macrocopa. Finally, three groups of catfish were fed these corresponding groups of M. macrocopa. After C. vulgaris was exposed to 3.50 mg l{sup -1} Cd (experimental group 2), the residual Cd in solution was only 4.01 {mu}g l{sup -1}, lower than the maximum allowable limit of Cd in natural water sources (5 {mu}g l{sup -1}). Cd concentrations in C. vulgaris were 0.01 {+-} 0.00 {mu}g g{sup -1} (dry wt) in the control group, 194 {+-} 1.80 {mu}g g{sup -1} (dry wt) in experimental group 1, and 1140 {+-} 20.06 {mu}g g{sup -1} (dry wt) in experimental group 2. The Cd concentrations in M. macrocopa were 0.01 {+-} 0.00 {mu}g g{sup -1} (dry wt) in the control group, 16.48 {+-} 2.23 {mu}g g{sup -1} (dry wt) in experimental group 1, and 56.6 {+-} 3.23 {mu}g g{sup -1} (dry wt) in experimental group 2. The Cd concentrations in catfish muscle increased with increasing Cd concentrations in the food. After 60 days of fish culture, the mean concentrations of Cd in fish muscle were 0.01 {+-} 0.00 {mu}g g{sup -1} (dry wt) in the control group, 0.61 {+-} 0.02 {mu}g g{sup -1} (dry wt) in experimental group 1 and 1.04 {+-} 0.06 {mu}g g{sup -1} (dry wt) in experimental group 2. Cd concentration in fish muscle of experimental group 2 was equal to the permissible limit. Cd accumulation affected fish growth: at the end of the study, the mean fresh weight (12.81 g) of catfish in the control group, was significantly higher than those experimental group 1 (10.43 g) and experimental group 2 (10.00 g). The results showed that the measurement of Cd concentration in water does not necessarily give a measure of the safety of aquatic organisms as human food. Hence, heavy metal contamination is a matter for concern when organisms are harvested, for fish and human consumption, from natural water sources.

  13. Entomophytophagy ('Sequential Predatory, then Phytophagous Behaviour' in an Indian Braconid 'Parasitoid' Wasp (Hymenoptera: Specialized Larval Morphology, Biology and Description of a New Species.

    Directory of Open Access Journals (Sweden)

    A P Ranjith

    Full Text Available The vast majority of braconid wasps are parasitoids of other insects. Although a few cases of pure phytophagy (primary gall production and seed predation are known, no previous entomophytophagous species (i.e. ones that display entomophagy and phytophagy sequentially, has been discovered among braconids. We describe the detailed biology and specialized larval morphology for the first confirmed entomophytophagous braconid species. Leaf galls on Garuga pinnata Roxb. (Burseraceae in India, induced by the psyllid, Phacopteron lentiginosum Buckton (Hemiptera: Psylloidea, Phacopteronidae were sampled throughout a period of several months and found to suffer a high level of attack by a new species Bracon garugaphagae Ranjith & Quicke which is here described and illustrated. The wasps oviposit singly into the galls without paralysing the psyllids. The larvae first attack psyllid nymphs which they seek out within the gall, kill them with a single bite and consume them. Unique dorsal abdominal tubercles, with eversible tips present on the abdominal segments of the larvae that are used to help maintain larval position while feeding, are illustrated. After consuming all available prey, the larvae continue feeding on gall tissue until mature enough to spin cocoons and pupate. The new species illustrates, for the first time, a possible intermediate stage in the evolution of pure phytophagy within the Braconidae. Interestingly, the two unrelated seed predator Bracon species are also associated with Burseraceae, perhaps indicating that this plant family is particularly suited as a food for braconine wasps.

  14. Entomophytophagy ('Sequential Predatory, then Phytophagous Behaviour') in an Indian Braconid 'Parasitoid' Wasp (Hymenoptera): Specialized Larval Morphology, Biology and Description of a New Species.

    Science.gov (United States)

    Ranjith, A P; Quicke, Donald L J; Saleem, U K A; Butcher, Buntika A; Zaldívar-Riverón, Alejandro; Nasser, M

    2016-01-01

    The vast majority of braconid wasps are parasitoids of other insects. Although a few cases of pure phytophagy (primary gall production and seed predation) are known, no previous entomophytophagous species (i.e. ones that display entomophagy and phytophagy sequentially), has been discovered among braconids. We describe the detailed biology and specialized larval morphology for the first confirmed entomophytophagous braconid species. Leaf galls on Garuga pinnata Roxb. (Burseraceae) in India, induced by the psyllid, Phacopteron lentiginosum Buckton (Hemiptera: Psylloidea, Phacopteronidae) were sampled throughout a period of several months and found to suffer a high level of attack by a new species Bracon garugaphagae Ranjith & Quicke which is here described and illustrated. The wasps oviposit singly into the galls without paralysing the psyllids. The larvae first attack psyllid nymphs which they seek out within the gall, kill them with a single bite and consume them. Unique dorsal abdominal tubercles, with eversible tips present on the abdominal segments of the larvae that are used to help maintain larval position while feeding, are illustrated. After consuming all available prey, the larvae continue feeding on gall tissue until mature enough to spin cocoons and pupate. The new species illustrates, for the first time, a possible intermediate stage in the evolution of pure phytophagy within the Braconidae. Interestingly, the two unrelated seed predator Bracon species are also associated with Burseraceae, perhaps indicating that this plant family is particularly suited as a food for braconine wasps.

  15. First time identification of Acanthamoeba genotypes in the cornea samples of wild birds; Is Acanthamoeba keratitis making the predatory birds a target?

    Science.gov (United States)

    Karakavuk, Muhammet; Aykur, Mehmet; Şahar, Esra Atalay; Karakuş, Mehmet; Aldemir, Duygu; Döndüren, Ömer; Özdemir, Hüseyin Gökhan; Can, Hüseyin; Gürüz, Adnan Yüksel; Dağcı, Hande; Döşkaya, Mert

    2017-12-01

    Acanthamoeba is a free-living amoeba which can be isolated from environment and among others well known as an opportunist protozoan parasite causing infections in humans and animals. Eyes are extremely important for the wild birds and losing sight ability due to Acanthamoeba can be dangerous. The studies on Acanthamoeba infection in wild birds is very few in world and Turkey therefore we aimed to screen deceased wild birds found in İzmir and Manisa provinces located in western Turkey using PCR and non-nutrition agar (NNA) plate method. Cornea samples were obtained from 18 deceased wild birds. During the external examination, signs of keratitis were observed in two Eurasian sparrowhawks (Accipiter nisus). All of the corneal samples were analyzed by two PCR methods and NNA plate. According to results, the Acanthamoeba positivity in corneal samples was 16.6% and 5.5% by PCR and plate method, respectively. According to sequencing data, two of isolates belonged to genotype T5 and one was genotype T4. In conclusion, Acanthamoeba infection was detected in wild bird cornea samples with/without keratitis for the first time in the world. The result of this study also show that Acanthamoeba can be a cause of keratitis in wild birds of Turkey and thus these predator birds can be a target of other wild animals due to loss of sight ability. In terms of public health, these results show the importance of wild birds as a source of Acanthamoeba infection in nature. Copyright © 2017 Elsevier Inc. All rights reserved.

  16. The Potential Application and Risks Associated With the Use of Predatory Bacteria as a Bio-control Agent Against Wound Infections

    Science.gov (United States)

    2015-10-01

    213: 428–431. 21. Dwidar M, Monnappa AK, Mitchell RJ (2012) The dual probiotic and antibiotic nature of Bdellovibrio bacteriovorus. BMB Rep 45: 71–78...and characterization of two bacteriophages with strong in vitro antimicrobial activity against Pseudomonas aeruginosa isolated from dogs with ocular...infections. Am J Vet Res 72: 1079–1086. 4. Dwidar M, Monnappa AK, Mitchell RJ (2012) The dual probiotic and antibiotic nature of Bdellovibrio

  17. Predicting predatory impact of juvenile invasive lionfish (Pterois volitans) on a crustacean prey using functional response analysis: effects of temperature, habitat complexity and light regimes

    KAUST Repository

    South, Josie; Dick, Jaimie T. A.; McCard, Monica; Barrios-O’ Neill, Daniel; Anton, Andrea

    2017-01-01

    The ecological implications of biotic interactions, such as predator-prey relationships, are often context-dependent. Comparative functional responses analysis can be used under different abiotic contexts to improve understanding and prediction

  18. In-vitro predatory activity of nematophagous fungi from Costa Rica with potential use for controlling sheep and goat parasitic nematodes

    Directory of Open Access Journals (Sweden)

    Natalia Soto-Barrientos

    2011-03-01

    Full Text Available In tropical and subtropical regions of the world, parasitic diseases are a main cause of losses in livestock productivity. The increased acquired resistence to anthelmintics by gastrointestinal nematodes, requires biological control be considered as a potential feasible and effective alternative. The most effective natural soil enemies of nematodes are nematophagous fungi. In order to collect and identify predator nematophagous fungi (PNF, samples were obtained from 51 farms distributed throughout the seven provinces of Costa Rica. The origin samples included: soil from different crops (potatoes, tomatoes, bananas, ornamental plants, squash and coffee; animal feces (cattle, sheep, goat and horse; soil and fallen leaves from forest; and plants with signs of nematode infection. Each sample was processed using three techniques for the extraction of fungi from soil: sprinkling technique, soil dilution and humidity chamber. Twenty four strains of nematophagous fungi were found in 19 farms; 83.3% of the fungi were isolated by sprinkling technique. The following fungi were idenified: Arthrobotrys oligospora (n=13; Candelabrella musiformis (n=9; and for the first time there was isolation of A. conoides (n=1 and A. dactyloides (n=1 in the country. Moreover, 16 strains from Trichoderma (n=13, Beauveria (n=1, Clonostachys (n=1 and Lecanicillium (n=1 were obtained. In addition, pH of each possible fungal isolation source was measured, and it varied from 5.2 to 9.9, however PNF isolates fell within the range of 5.6 to 7.5. The PNF strains were cultivated in four different media for the production of chhlamydospores: potato dextrose agar (PDA; corn meal agar (CMA; malt extract agar (MEA and potato carrot agar (PCA. Out of these cultures, 95.8% of the strains formed chlamydospores primarily in the PCA. Of these strains, the profilic spore producers were subjected to ruminant artificial gastrointestinal conditions. A total of 14 fungi were tested, out of which 42.9% survived the digestive analysis. Neither A. conoides nor A. dactyloides were viable following the in vitro gastrointestinal test. The PNF isolated in this study demostrated an action against ovine and caprine gastrointestinal nematodes and are candidates for use in biological control of these organisms. Among these microorganisms, Candelabrella musiformis appears to be the most promising fungi for use as a biological control agent in Costa Rica. Rev. Biol. Trop. 59 (1: 37-52. Epub 2011 March 01.

  19. In-vitro predatory activity of nematophagous fungi from Costa Rica with potential use for controlling sheep and goat parasitic nematodes.

    Science.gov (United States)

    Soto-Barrientos, Natalia; de Oliveira, Jaqueline; Vega-Obando, Rommel; Montero-Caballero, Danilo; Vargas, Bernardo; Hernández-Gamboa, Jorge; Orozco-Solano, Claudio

    2011-03-01

    In tropical and subtropical regions of the world, parasitic diseases are a main cause of losses in livestock productivity. The increased acquired resistence to anthelmintics by gastrointestinal nematodes, requires biological control be considered as a potential feasible and effective alternative. The most effective natural soil enemies of nematodes are nematophagous fungi. In order to collect and identify predator nematophagous fungi (PNF), samples were obtained from 51 farms distributed throughout the seven provinces of Costa Rica. The origin samples included: soil from different crops (potatoes, tomatoes, bananas, ornamental plants, squash and coffee); animal feces (cattle, sheep, goat and horse); soil and fallen leaves from forest; and plants with signs of nematode infection. Each sample was processed using three techniques for the extraction of fungi from soil: sprinkling technique, soil dilution and humidity chamber. Twenty four strains of nematophagous fungi were found in 19 farms; 83.3% of the fungi were isolated by sprinkling technique. The following fungi were identified: Arthrobotrys oligospora (n = 13); Candelabrella musiformis (n = 9); and for the first time there was isolation of A. conoides (n = 1) and A. dactyloides (n = 1) in the country. Moreover, 16 strains from Trichoderma (n=13), Beauveria (n = 1), Clonostachys (n = 1) and Lecanicillium (n = 1) were obtained. In addition, pH of each possible fungal isolation source was measured, and it varied from 5.2 to 9.9, however PNF isolates fell within the range of 5.6 to 7.5. The PNF strains were cultivated in four different media for the production of chhlamydospores: potato dextrose agar (PDA); corn meal agar (CMA); malt extract agar (MEA) and potato carrot agar (PCA). Out of these cultures, 95.8% of the strains formed chlamydospores primarily in the PCA. Of these strains, the profilic spore producers were subjected to ruminant artificial gastrointestinal conditions. A total of 14 fungi were tested, out of which 42.9% survived the digestive analysis. Neither A. conoides nor A. dactyloides were viable following the in vitro gastrointestinal test. The PNF isolated in this study demonstrated an action against ovine and caprine gastrointestinal nematodes and are candidates for use in biological control of these organisms. Among these microorganisms, Candelabrella musiformis appears to be the most promising fungi for use as a biological control agent in Costa Rica.

  20. Immature stages of giants: morphology and growth characteristics of Goliathus Lamarck, 1801 larvae indicate a predatory way of life (Coleoptera, Scarabaeidae, Cetoniinae

    Directory of Open Access Journals (Sweden)

    Tomáš Vendl

    2016-09-01

    Full Text Available The third larval instar of Goliathus goliatus (Drury, 1770, G. orientalis Moser, 1909 and G. albosignatus Boheman, 1857 are described and illustrated for the first time and compared with the immature stages of other Cetoniinae. Larval development of G. goliatus is investigated under laboratory conditions, with particular emphasis on food requirements. These results support the obligatory requirement of proteins in the larval diet. The association between larval morphological traits (e. g., the shape of the mandibles and pretarsus, presence of well-developed stemmata and larval biology is discussed. Based on observations and the data from captive breeds it is concluded that a possible shift from pure saprophagy to an obligatory predaceous way of larval life occurred within the larvae of this genus, which may explain why these beetles achieve such an enormous size.

  1. A linguistic analysis of grooming strategies of online child sex offenders: Implications for our understanding of predatory sexual behavior in an increasingly computer-mediated world.

    Science.gov (United States)

    Black, Pamela J; Wollis, Melissa; Woodworth, Michael; Hancock, Jeffrey T

    2015-06-01

    There is a large body of evidence to suggest that child sex offenders engage in grooming to facilitate victimization. It has been speculated that this step-by-step grooming process is also used by offenders who access their underage victims online; however, little research has been done to examine whether there are unique aspects of computer-mediated communication that impact the traditional face-to-face grooming process. This study considered the similarities and differences in the grooming process in online environments by analyzing the language used by online offenders when communicating with their victims. The transcripts of 44 convicted online offenders were analyzed to assess a proposed theory of the online grooming process (O'Connell, 2003). Using a stage-based approach, computerized text analysis examined the types of language used in each stage of the offender-victim interaction. The transcripts also were content analyzed to examine the frequency of specific techniques known to be employed by both face-to-face and online offenders, such as flattery. Results reveal that while some evidence of the strategies used by offenders throughout the grooming process are present in online environments, the order and timing of these stages appear to be different. The types (and potential underlying pattern) of strategies used in online grooming support the development of a revised model for grooming in online environments. Copyright © 2015 Elsevier Ltd. All rights reserved.

  2. Bacterial communities associated with the digestive tract of the predatory ground beetle, Poecilus chalcites, and their response to laboratory rearing and antibiotic treatment

    Energy Technology Data Exchange (ETDEWEB)

    Michael Lehman

    2008-06-01

    Ground beetles such as Poecilus chalcites (Coleoptera: Carabidae) are beneficial insects in agricultural systems where they contribute to the control of insect and weed pests. We assessed the complexity of bacterial communities occurring in the digestive tracts of field-collected P. chalcites using terminal restriction fragment length polymorphism analyses of polymerase chain reaction-amplified 16S rRNA genes. Bacterial identification was performed by the construction of 16S rRNA gene clone libraries and sequence analysis. Intestinal bacteria in field-collected beetles were then compared to those from groups of beetles that were reared in the lab on an artificial diet with and without antibiotics. Direct cell counts estimated 1.5 × 10S bacteria per milliliter of gut. The digestive tract of field-collected P. chalcites produced an average of 4.8 terminal restriction fragments (tRF) for each beetle. The most abundant clones were affiliated with the genus Lactobacillus, followed by the taxa Enterobacteriaceae, Clostridia, and Bacteriodetes. The majority of the sequences recovered were closely related to those reported from other insect gastrointestinal tracts. Lab-reared beetles produced fewer tRF, an average of 3.1 per beetle, and a reduced number of taxa with a higher number of clones from the family Enterobacteriaceae compared to the field-collected beetles. Antibiotic treatment significantly (p < 0.05) reduced the number of tRF per beetle and selected for a less diverse set of bacterial taxa. We conclude that the digestive tract of P. chalcites is colonized by a simple community of bacteria that possess autochthonous characteristics. Laboratory-reared beetles harbored the most common bacteria found in field-collected beetles, and these bacterial communities may be manipulated in the laboratory with the addition of antibiotics to the diet to allow study of functional roles.

  3. Assessing bat droppings and predatory bird pellets for vector-borne bacteria: molecular evidence of bat-associated Neorickettsia sp. in Europe.

    Science.gov (United States)

    Hornok, Sándor; Szőke, Krisztina; Estók, Péter; Krawczyk, Aleksandra; Haarsma, Anne-Jifke; Kováts, Dávid; Boldogh, Sándor A; Morandini, Pál; Szekeres, Sándor; Takács, Nóra; Kontschán, Jenő; Meli, Marina L; Fernández de Mera, Isabel G; de la Fuente, José; Gyuranecz, Miklós; Sulyok, Kinga M; Weibel, Beatrice; Gönczi, Enikő; de Bruin, Arnout; Sprong, Hein; Hofmann-Lehmann, Regina

    2018-02-28

    In Europe, several species of bats, owls and kestrels exemplify highly urbanised, flying vertebrates, which may get close to humans or domestic animals. Bat droppings and bird pellets may have epidemiological, as well as diagnostic significance from the point of view of pathogens. In this work 221 bat faecal and 118 bird pellet samples were screened for a broad range of vector-borne bacteria using PCR-based methods. Rickettsia DNA was detected in 13 bat faecal DNA extracts, including the sequence of a rickettsial insect endosymbiont, a novel Rickettsia genotype and Rickettsia helvetica. Faecal samples of the pond bat (Myotis dasycneme) were positive for a Neorickettsia sp. and for haemoplasmas of the haemofelis group. In addition, two bird pellets (collected from a Long-eared Owl, Asio otus, and from a Common Kestrel, Falco tinnunculus) contained the DNA of a Rickettsia sp. and Anaplasma phagocytophilum, respectively. In both of these bird pellets the bones of Microtus arvalis were identified. All samples were negative for Borrelia burgdorferi s.l., Francisella tularensis, Coxiella burnetii and Chlamydiales. In conclusion, bats were shown to pass rickettsia and haemoplasma DNA in their faeces. Molecular evidence is provided for the presence of Neorickettsia sp. in bat faeces in Europe. In the evaluated regions bat faeces and owl/kestrel pellets do not appear to pose epidemiological risk from the point of view of F. tularensis, C. burnetii and Chlamydiales. Testing of bird pellets may provide an alternative approach to trapping for assessing the local occurrence of vector-borne bacteria in small mammals.

  4. Assessing bat droppings and predatory bird pellets for vector-borne bacteria: molecular evidence of bat-associated Neorickettsia sp. in Europe.

    NARCIS (Netherlands)

    Hornok, Sándor; Szőke, Krisztina; Estók, Péter; Krawczyk, Aleksandra; Haarsma, Anne-Jifke; Kováts, Dávid; Boldogh, Sándor A; Morandini, Pál; Szekeres, Sándor; Takács, Nóra; Kontschán, Jenő; Meli, Marina L; Fernández de Mera, Isabel G; de la Fuente, José; Gyuranecz, Miklós; Sulyok, Kinga M; Weibel, Beatrice; Gönczi, Enikő; de Bruin, Arnout; Sprong, Hein; Hofmann-Lehmann, Regina

    2018-01-01

    In Europe, several species of bats, owls and kestrels exemplify highly urbanised, flying vertebrates, which may get close to humans or domestic animals. Bat droppings and bird pellets may have epidemiological, as well as diagnostic significance from the point of view of pathogens. In this work 221

  5. Prey Preference of Predatory mite Amblyseius swirskii (Athias-Henriot (Acari: Phytoseiidae on untreated and Beauveria bassiana-treated of Trialeurodes vaporariorum (Homoptera: Aleyrodidae

    Directory of Open Access Journals (Sweden)

    Marjan Seiedy

    2018-01-01

    Full Text Available Introduction The predator Amblyseius swirskii and entomopathogenic fungus Beauveria bassiana are important biocontrol agents of Trialeurodes vaporariorum. Determination of the host preference of predators in the fields when receiving signals related to either untreated and Beauveria bassiana-treated pest is important. Materials and Methods In this research, the prey preference of adult female (2 days old of A. swirskii was determined on untreated and Beauveria bassiana-treated of Trialeurodes vaporariorum (Homoptera: Aleyrodidae in various treatments base on Manly Index. These different treatments consisted of two time intervals; 24 and 48 h post-inoculation of greenhouse whiteflies with 1×105 conidia /ml of B. bassiana with 13 replicates. 24-h starved predators were added to the leaf discs singly then the number of consumed untreated and B. bassiana-treated T. vaporariorum in each Petri dish was assessed after 24 h. Results and Discussion The results revealed that mean number of consumed B. bassiana-treated T. vaporariorum in two time intervals; 24 and 48 h. after inoculation were 4/15±0/19 and 2.23±0/12, respectively. This investigation showed a significant preference of A. swirskii towards untreated T. vaporariorum in 24 (P< 0.0034 and 48 h. (P

  6. Plant structural changes due to herbivory: Do changes in Aceria-infested coconut fruits allow predatory mites to move under the perianth?

    NARCIS (Netherlands)

    Aratchige, N.S.; Sabelis, M.W.; Lesna, I.K.A.

    2007-01-01

    Being minute in size, eriophyoid mites can reach places that are small enough to be inaccessible to their predators. The coconut mite, Aceria guerreronis, is a typical example; it finds partial refuge under the perianth of the coconut fruit. However, some predators can move under the perianth of the

  7. Acinonyx pardinensis (Carnivora, Felidae) from the Early Pleistocene of Pantalla (Italy): predatory behavior and ecological role of the giant Plio-Pleistocene cheetah

    Science.gov (United States)

    Cherin, Marco; Iurino, Dawid Adam; Sardella, Raffaele; Rook, Lorenzo

    2014-03-01

    The site of Pantalla (central Italy) yielded a rich late Villafranchian (Early Pleistocene) faunal assemblage, which includes some well-preserved large mammal skulls. We describe here two nearly complete crania and a left hemimandible of Acinonyx pardinensis from this locality, representing the most complete cranial material of this species in Europe. These finds allowed us to define more clearly the craniodental morphology of A. pardinensis. Similarly to the forms from North Africa and China, the giant cheetah from Pantalla has a more generalized skull than the living Acinonyx jubatus, showing some primitive, pantherine-like features such as the less domed dorsal outline of the cranium, the more developed sagittal and nuchal crests and the less bowed zygomatic arches. High-resolution CT scans of the specimens were used to obtain the first 3D model of a cranium with articulated mandible of A. pardinensis. Starting from the insertion areas on this model we reconstructed the jaw muscles of the Pantalla felid, confirming its affinities with pantherine felines. In the light of the musculoskeletal skull anatomy and the average body mass (about 80 kg), it is likely that A. pardinensis could kill large prey through a hunting strategy more similar to pantherine cats than to the living cheetah.

  8. Population transcriptomes reveal synergistic responses of DNA polymorphism and RNA expression to extreme environments on the Qinghai-Tibetan Plateau in a predatory bird.

    Science.gov (United States)

    Pan, Shengkai; Zhang, Tongzuo; Rong, Zhengqin; Hu, Li; Gu, Zhongru; Wu, Qi; Dong, Shanshan; Liu, Qiong; Lin, Zhenzhen; Deutschova, Lucia; Li, Xinhai; Dixon, Andrew; Bruford, Michael W; Zhan, Xiangjiang

    2017-06-01

    Low oxygen and temperature pose key physiological challenges for endotherms living on the Qinghai-Tibetan Plateau (QTP). Molecular adaptations to high-altitude living have been detected in the genomes of Tibetans, their domesticated animals and a few wild species, but the contribution of transcriptional variation to altitudinal adaptation remains to be determined. Here we studied a top QTP predator, the saker falcon, and analysed how the transcriptome has become modified to cope with the stresses of hypoxia and hypothermia. Using a hierarchical design to study saker populations inhabiting grassland, steppe/desert and highland across Eurasia, we found that the QTP population is already distinct despite having colonized the Plateau adaptation to hypothermia. Our results exemplify synergistic responses between DNA polymorphism and RNA expression diversity in coping with common stresses, underpinning the successful rapid colonization of a top predator onto the QTP. Importantly, molecular mechanisms underpinning highland adaptation involve relatively few genes, but are nonetheless more complex than previously thought and involve fine-tuned transcriptional responses and genomic adaptation. © 2017 The Authors. Molecular Ecology Published by John Wiley & Sons Ltd.

  9. A revised and dated phylogeny of cobweb spiders (Araneae, Araneoidea, Theridiidae): A predatory Cretaceous lineage diversifying in the era of the ants (Hymenoptera, Formicidae).

    Science.gov (United States)

    Liu, Jie; May-Collado, Laura J; Pekár, Stano; Agnarsson, Ingi

    2016-01-01

    Cobweb spiders (Theridiidae) are highly diverse from the perspective of species richness, morphological diversity, variety of web architecture, and behavioral repertoires. The family includes over 50% of social spiders, a behavioral rarity among the order, and members of the family are furthermore the subject of research on venom, silk biomechanics, kleptoparasitism and web building, among other traits. Theridiidae is one of the most abundant groups of spiders, and thus key insect predators in many different ecosystems and is among relatively few spider families that show high degree of myrmecophagy. Modern comparative studies on all these fronts are best buttressed on a phylogenetic foundation. Our goal here is to offer a revised, dated, phylogenetic hypothesis for the family by summarizing previously published data from multiple molecular and morphological studies through data-mining, and adding novel data from several genera. We also test the hypothesis that the origin and diversification of cobweb spiders coincides with that of ants on which many species specialize as prey. The new phylogeny is largely congruent with prior studies and current taxonomy and should provide a useful tool for theridiid classification and for comparative analyses. Nevertheless, we also highlight the limitations of currently available data-the state of the art in Theridiidae phylogenetics-offering weak support for most of the deeper nodes in the phylogeny. Thus the need is clear for modern phylogenomic approaches to obtain a more solid understanding, especially of relationships among subfamilies. We recover the monophyly of currently recognized theridiid subfamilies with the exception of some enigmatic 'pholcommatines' (Styposis, Phoroncidia) and putative 'hadrotarsines' (Audifia, Tekellina) whose placement is uncertain in our analyses. Theridiidae dates back some 100 mya to the Cretaceous, a period of diversification in flowering plants and many groups of insects, including ants. The origin of cobweb spiders, and hence the cobweb-a speciallized trap for pedestrian prey-coincides with a major diversification shift in ants. The family becomes abundant in fossil record 50-40 mya as ants also diversify and reach dominance and contemporary patterns of abundances of theridiids and ants show the same trends, with increasing relative abundance towards the equator and at lower altitudes. We find that among orbiculariae, lineages that specialize on ant prey are non-randomly clustered within Theridiidae. Given these findings we hypothesize that the origin of the gumfoot web was a stepping stone that facilitated the capture of ants and resulted in specialized myrmecophagy in a number of 'basal' theridiids. We also document a subsequent loss in myrmecophagy, and associated increase in speciation rates, as 'recent' theridiid groups evolve diverse web forms and many return to the capture of aerial prey. Copyright © 2015 Elsevier Inc. All rights reserved.

  10. Is web oscillation in the orb-web spider Argiope lobata (Pallas, 1772)(Araneidae) an anti-predatory behaviour?

    DEFF Research Database (Denmark)

    Cedhagen, Tomas; Björklund, S.

    2007-01-01

    A specimen of Argiope lobata was observed oscillating itself and its web in a regular way when disturbed. This behaviour made it invisible, and is interpreted as a reaction for avoiding being seen by predators. A combination of four factors is important; (I) The large body mass and the long legs ...

  11. Vitamin A deficiency modifies response of predatory mite Amblyseius potentillae to volatile kairomone of two-spotted spider mite, Tetranychus urticae.

    NARCIS (Netherlands)

    Dicke, M.; Sabelis, M.W.; Groeneveld, A.

    1986-01-01

    volatile kairomone of the two-spotted spider mite,Tetranychus urticae, elicits a searching response of the phytoseiid predatorAmblyseius potentillae, only when the predator is reared on a carotenoid-free diet. However, after addition of crystalline betta-carotene or vitamin A acetate to the

  12. Is Recovery of Large-Bodied Zooplankton after Nutrient Loading Reduction Hampered by Climate Warming? A Long-Term Study of Shallow Hypertrophic Lake Sobygaard, Denmark

    DEFF Research Database (Denmark)

    Florencia Gutierrez, Maria; Devercelli, Melina; Brucet Balmana, Sandra

    2016-01-01

    biomass of cladocerans increased coinciding with a diminished fish catch per unit effort (CPUE), and likely then an overall reduction in the predation on zooplankton. A cascading effect to phytoplankton was evidenced by enhanced zooplankton: phytoplankton and cladoceran: phytoplankton ratios...... on phytoplankton through an expected diminished fish CPUE related to nutrient loading reduction....

  13. Planktonic Crustacean Culture - Live Planktonic Crustaceans as Live Feed for Finfish and Shrimps in Aquaculture

    DEFF Research Database (Denmark)

    Jepsen, Per Meyer; Syberg, Kristian; Drillet, Guillaume

    2018-01-01

    The cultivation of planktonic crustaceans as live feed is of paramount importance for the aquaculture and aquarium industries. The use of live cladocerans as feed for freshwater fish is limited to the aquarium industry, whereas Artemia and copepods are used to feed edible marine fish larvae...... assessments for hazardous chemicals. Cladocerans are widely used for ecotoxicology testing but Artemia and copepods are emerging new model species. In the present chapter, we review the culturing procedures of these important planktonic crustaceans: Artemia, cladocerans and copepods and discuss their use...

  14. Zooplankton ecology in the Mandovi-Zuari estuarine system of Goa, west coast of India

    Digital Repository Service at National Institute of Oceanography (India)

    Padmavati, G.; Goswami, S.C.

    .6%). Invertebrate larvae, luciferied shrimps, cladocerans and chaetognaths were the other common zooplankton groups. Distribution and abundance of majority of constituent groups and species were influenced by various hydrographical characteristics of the environment....

  15. Live feed culture - Problems and perspectives

    Digital Repository Service at National Institute of Oceanography (India)

    Royan, J.P.

    The importance of live feed in aquaculture is stressed. Organisms currently cultured as live feed are microalgae, turbellarians, tanaidaceans, annelids, brine shrimps, fairy shrimps, rotifers, cladocerans and copepods. Their culture methods...

  16. Seasonality in meiofaunal distribution on a tropical beach at Balramgari, northeast coast of India

    Digital Repository Service at National Institute of Oceanography (India)

    Chatterji, A; Ansari, Z.A; Mishra, J.K.; Parulekar, A

    in isopods and patchy or contagious in nematodes, turbellaria, amphipoda and cladocera with salinity, pH, chlorophyll-a and POC respectively. Mean grain size of the sediment was highly correlated with the abundance of cladocerans and harpacticods...

  17. Zooplankton biomass and composition in the western Bay of Bengal during late sw monsoon

    Digital Repository Service at National Institute of Oceanography (India)

    Achuthankutty, C.T.; Madhupratap, M.; Nair, V.R.; Nair, S.R.S.; Rao, T.S.S.

    and neritic regions of the southwestern Bay of Bengal. Other groups like chaetognaths, ostracods, amphipods, euphausiids, fish eggs, fish larvae, polychaetes, cladocerans, planktonic molluscs, etc. contributed to a lesser percentage of the general composition...

  18. Zooplankton production, composition and diversity in the coastal waters of Goa

    Digital Repository Service at National Institute of Oceanography (India)

    Goswami, S.C.; Padmavati, G.

    , siphonophores, chaetognaths and fish eggs were the other common taxa. Zooplankton population was never dominated by a single group. Swarms of copepods (Temora turbinata), cladocerans (Evadne tergestina), and pteropods (Creseis acicula) occurred in the nutrient...

  19. Seasonal fluctuations in the occurrence of Cladocera in the Mandovi-Zuari estuarine waters of Goa

    Digital Repository Service at National Institute of Oceanography (India)

    Goswami, S.C.; Devassy, V.P

    .78). Evadne tergestina Claus and Penilia avirostris Dana were the 2 major species representing cladoceran population, the former being dominant (85.88%). Both the species were characterisEd. by seasonality in distribution. Distribution patterns of each species...

  20. Post-truth era and impact on the science associated with sport and ...

    African Journals Online (AJOL)

    Kathryn van Boom

    selfie, a picture taken of oneself typically with a smartphone ... scientific process. A problem threatening this process is the emergence of predatory journals. [3] The business model of predatory journal use contributes to the short circuiting of the.