Somatotrophs and lactotrophs: an immunohistochemical study of Gallus domesticus pituitary gland at different stages of induced moult

Directory of Open Access Journals (Sweden)

M. A. Sandhu

2010-05-01

Full Text Available The objective of this study was to determine the distribution of somatotrophs and lactotrophs and conduct a morphometrical analysis of immunoreactive somatotrophs and lactotrophs in the pituitary glands of White Leghorn Hens (Gallus domesticus during the period of induced moult. We divided the periods of induced moulting into three phases viz. 7, 14 and 21 days. The labeled alkaline-phsphatase method with anti-GH (growth hormone and anti-PRL (prolactin as a primary antibody was used to detect somatotrophs and lactotrophs, in the midsagital sections of chicken adenohypophysis. Immunohistochemistry showed that somatotrophs are not only confined to the cephalo-caudal axis but can also be found in the caudal lobe; while lactotrophs were distributed in both lobes of the anterior pituitary gland at all stages of moulting (7, 14 and 21 days. Lactotrophs were of different shapes but somatotrophs were oval to round in morphology. At the given stages of induced moulting, some hypertrophied lactotrophs were also present after 7 days of induced moult in the anterior pituitary gland. However, there were moulting-related changes: from 7 to 21 days of induced moulting the immunoreactive-PRL cell population decreased, while the mean lactotroph size was more than that of somatotrophs. Basic quantitative and morphological information relating to somatotrophs and lactotrophs during the period of induced moult in laying hens is reported here and the changes brought about by induced moulting are restricted to PRL positive cells rather than GH positive cells.

Re-assessing copepod growth using the Moult Rate method

DEFF Research Database (Denmark)

Hirst, Andrew G.; Keister, J. E.; Richardson, A. J.

2014-01-01

Estimating growth and production rates of mesozooplankton, and copepods in particular, is important in describing flows of material and energy though pelagic systems. Over the past 30 years, the Moult Rate (MR) method has been used to estimate juvenile copepod growth rates in ∼40 papers. Yet the MR......-moulting stage, e.g. copepodite stage 5 to adult. We performed experiments with Calanus pacificus to estimate growth of stage C5 using an alternative method. We found that the error size and sign varied between mass type (i.e. DW, C and N). Recommendations for practical future assessments of growth in copepods...

Waterfowl habitat use and selection during the remigial moult period in the northern hemisphere

Science.gov (United States)

Fox, Anthony D.; Flint, Paul L.; Hohman, William L.; Savard, Jean-Pierre L.

2014-01-01

This paper reviews factors affecting site selection amongst waterfowl (Anatidae) during the flightless remigial moult, emphasising the roles of predation and food supply (especially protein and energy). The current literature suggests survival during flightless moult is at least as high as at other times of the annual cycle, but documented cases of predation of flightless waterfowl under particular conditions lead us to infer that habitat selection is generally highly effective in mitigating or avoiding predation. High energetic costs of feather replacement and specific amino-acid requirements for their construction imply adoption of special energetic and nutritional strategies at a time when flightlessness limits movements. Some waterfowl meet their energy needs from endogenous stores accumulated prior to remigial moult, others rely on exogenous supply, but this varies with species, age, reproductive status and site. Limited evidence suggests feather proteins are derived from endogenous and exogenous sources which may affect site selection. Remigial moult does not occur independently of other annual cycle events and is affected by reproductive investment and success. Hence, moult strategies are affected by age, sex and reproductive history, and may be influenced by the need to attain a certain internal state for the next stage in the annual cycle (e.g. autumn migration). We know little about habitat selection during moult and urge more research of this poorly known part of the annual cycle, with particular emphasis on identifying key concentrations and habitats for specific flyway populations and the effects of disturbance upon these. This knowledge will better inform conservation actions and management actions concerning waterfowl during moult and the habitats that they exploit.

Exploring Moulting Common Eider (Somateria mollissima) Escape Responses towards Ship Traffic.

OpenAIRE

Skei, Jørgen

2014-01-01

1. The construction of bottom dwelling offshore wind farms in shallow waters is expected to interfere with seabird feeding and moulting habitats. This study focus on how the disturbance from ship traffic associated with construction and maintenance of offshore wind farms influence moulting common eiders. Such studies might help forming guidelines to minimize potential conflicts between seabirds and the establishment of bottom dwelling offshore wind farms. 2. The study was conducted in coas...

The transcriptional landscape of seasonal coat colour moult in the snowshoe hare.

Science.gov (United States)

Ferreira, Mafalda S; Alves, Paulo C; Callahan, Colin M; Marques, João P; Mills, L Scott; Good, Jeffrey M; Melo-Ferreira, José

2017-08-01

Seasonal coat colour change is an important adaptation to seasonally changing environments but the evolution of this and other circannual traits remains poorly understood. In this study, we use gene expression to understand seasonal coat colour moulting in wild snowshoe hares (Lepus americanus). We used hair colour to follow the progression of the moult, simultaneously sampling skin from three moulting stages in hares collected during the peak of the spring moult from white winter to brown summer pelage. Using RNA sequencing, we tested whether patterns of expression were consistent with predictions based on the established phases of the hair growth cycle. We found functionally consistent clustering across skin types, with 766 genes differentially expressed between moult stages. "White" pelage showed more differentially expressed genes that were upregulated relative to other skin types, involved in the transition between late telogen (quiescent stage) and the onset of anagen (proliferative stage). Skin samples from transitional "intermediate" and "brown" pelage were transcriptionally similar and resembled the regressive transition to catagen (regressive stage). We also detected differential expression of several key circadian clock and pigmentation genes, providing important means to dissect the bases of alternate seasonal colour morphs. Our results reveal that pelage colour is a useful biomarker for seasonal change but that there is a consistent lag between the main gene expression waves and change in visible coat colour. These experiments establish that developmental sampling from natural populations of nonmodel organisms can provide a crucial resource to dissect the genetic basis and evolution of complex seasonally changing traits. © 2017 John Wiley & Sons Ltd.

Differential gene expression during the moult cycle of Antarctic krill (Euphausia superba

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Gaten Edward

2010-10-01

Full Text Available Abstract Background All crustaceans periodically moult to renew their exoskeleton. In krill this involves partial digestion and resorption of the old exoskeleton and synthesis of new cuticle. Molecular events that underlie the moult cycle are poorly understood in calcifying crustaceans and even less so in non-calcifying organisms such as krill. To address this we constructed an Antarctic krill cDNA microarray in order to generate gene expression profiles across the moult cycle and identify possible activation pathways. Results A total of 26 different cuticle genes were identified that showed differential gene expression across the moult cycle. Almost all cuticle genes were up regulated during premoult and down regulated during late intermoult. There were a number of transcripts with significant sequence homology to genes potentially involved in the synthesis, breakdown and resorption of chitin. During early premoult glutamine synthetase, a gene involved in generating an amino acid used in the synthesis of glucosamine, a constituent of chitin, was up regulated more than twofold. Mannosyltransferase 1, a member of the glycosyltransferase family of enzymes that includes chitin synthase was also up regulated during early premoult. Transcripts homologous to a β-N-acetylglucosaminidase (β-NAGase precursor were expressed at a higher level during late intermoult (prior to apolysis than during premoult. This observation coincided with the up regulation during late intermoult, of a coatomer subunit epsilon involved in the production of vesicles that maybe used to transport the β-NAGase precursors into the exuvial cleft. Trypsin, known to activate the β-NAGase precursor, was up regulated more than fourfold during premoult. The up regulation of a predicted oligopeptide transporter during premoult may allow the transport of chitin breakdown products across the newly synthesised epi- and exocuticle layers. Conclusion We have identified many genes

Gene expression profiling of cuticular proteins across the moult cycle of the crab Portunus pelagicus

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Kuballa Anna V

2007-10-01

Full Text Available Abstract Background Crustaceans represent an attractive model to study biomineralization and cuticle matrix formation, as these events are precisely timed to occur at certain stages of the moult cycle. Moulting, the process by which crustaceans shed their exoskeleton, involves the partial breakdown of the old exoskeleton and the synthesis of a new cuticle. This cuticle is subdivided into layers, some of which become calcified while others remain uncalcified. The cuticle matrix consists of many different proteins that confer the physical properties, such as pliability, of the exoskeleton. Results We have used a custom cDNA microarray chip, developed for the blue swimmer crab Portunus pelagicus, to generate expression profiles of genes involved in exoskeletal formation across the moult cycle. A total of 21 distinct moult-cycle related differentially expressed transcripts representing crustacean cuticular proteins were isolated. Of these, 13 contained copies of the cuticle_1 domain previously isolated from calcified regions of the crustacean exoskeleton, four transcripts contained a chitin_bind_4 domain (RR consensus sequence associated with both the calcified and un-calcified cuticle of crustaceans, and four transcripts contained an unannotated domain (PfamB_109992 previously isolated from C. pagurus. Additionally, cryptocyanin, a hemolymph protein involved in cuticle synthesis and structural integrity, also displays differential expression related to the moult cycle. Moult stage-specific expression analysis of these transcripts revealed that differential gene expression occurs both among transcripts containing the same domain and among transcripts containing different domains. Conclusion The large variety of genes associated with cuticle formation, and their differential expression across the crustacean moult cycle, point to the complexity of the processes associated with cuticle formation and hardening. This study provides a molecular entry path

Protein synthesis in body wall and midgut during the larval moulting cycle of the silkworm, Bombyx mori

International Nuclear Information System (INIS)

Nagata, Masao

1976-01-01

14 C-leucine was injected into larvae at various points of time during the fourth moulting cycle, and four hours after the injection, dissection was carried out. The intake of radioactivity into the proteins of body wall and midgut was investigated. The specific activity of the proteins changed with the moulting of larvae, but the specific activity of the amino acid pool in tissues also changed. Accordingly, the change of specific activity in proteins was not able to be regarded as the variation of synthetic capability. The ratio of the specific activity of proteins to that of amino acid pool was determined, and it was revealed that the capability of protein synthesis of body wall and midgut was high in feeding period and lowered in moulting period, and it was different according to various stages of moulting period. As the result of investigation on the time course of the specific activity of proteins of body wall and midgut after the injection of 14 C-leucine, it was shown that the specific activity reached the maximum earlier in feeding period than in moulting period. The intake of 14 C-leucine into body wall and midgut was examined with 20 min. labeling, consequently the specific activity of proteins was high in feeding period and low in moulting period. The capability of protein synthesis was active in feeding period and dwindled in moulting period in case of the whole body of larvae. (Kako, I.)

Simulated moult reduces flight performance but overlap with breeding does not affect breeding success in a long-distance migrant

NARCIS (Netherlands)

Tomotani, Barbara M.; Muijres, Florian T.; Koelman, Julia; Casagrande, Stefania; Visser, Marcel E.

2018-01-01

* Long-distance migrants are time-constrained as they need to incorporate many annual cycle stages within a year. Migratory passerines moult in the short interval between breeding and migration. To widen this interval, moult may start while still breeding, but this results in flying with moulting

Simulated moult reduces flight performance but overlap with breeding does not affect breeding success in a long-distance migrant

NARCIS (Netherlands)

Mizumo Tomotani, Barbara; Muijres, F.T.; Koelman, Julia; Casagrande, Stefania; Visser, Marcel E.

2018-01-01

1.Long-distance migrants are time-constrained as they need to incorporate many annual cycle stages within a year. Migratory passerines moult in the short interval between breeding and migration. To widen this interval, moult may start while still breeding, but this results in flying with moulting

Effects of eyestalk ablation on moulting and growth of penaeid prawn Metapenaeus dobsoni (de Man)

Digital Repository Service at National Institute of Oceanography (India)

Venkitraman, P.R; Jayalakshmy, K.V.; Balasubramanian, T.; Nair, M.; Nair, K.K.C.

group, 35-40 mm, but consumed about 57.8% more food than the control prawns in the larger size group, 48-53 mm. Growth was estimated as length and weight changes and significant variation was observed. The moult rate and dry moult weight showed marked...

Breeding seasonality and primary moult parameters of Euplectes ...

African Journals Online (AJOL)

The grassland biome in South Africa has a summer rainfall and Southern Red Bishops Euplectes orix, Fan-tailed Widows E. axillaris, White-winged Widow E. albonotatus, Red-collared Widow E. ardens and Long-tailed Widow E. progne breed from October or November to March. Primary moult starts in late March or early ...

Change of external sexual characteristics during consecutive moults in Crangon crangon L

Science.gov (United States)

Schatte, Jessica; Saborowski, Reinhard

2006-03-01

Adult males of the North Sea shrimp, Crangon crangon, were maintained for 8 months in the laboratory under natural temperature and light cycles. Successive moults were analysed for morphological changes. Out of the 70 shrimps, one male performed morphological sex reversal by reducing the male characteristics and developing female characteristics. The morphological changes including the loss of the appendix masculina appeared within a single moult cycle. This observation proves that C. crangon males may be capable of changing sex. The low number of sex reversals indicates that C. crangon is a facultative rather than an obligate protandric hermaphrodite.

Elucidating mechanisms for insect body size: partial support for the oxygen-dependent induction of moulting hypothesis.

Science.gov (United States)

Kivelä, Sami M; Viinamäki, Sonja; Keret, Netta; Gotthard, Karl; Hohtola, Esa; Välimäki, Panu

2018-01-25

Body size is a key life history trait, and knowledge of its mechanistic basis is crucial in life history biology. Such knowledge is accumulating for holometabolous insects, whose growth is characterised and body size affected by moulting. According to the oxygen-dependent induction of moulting (ODIM) hypothesis, moult is induced at a critical mass at which oxygen demand of growing tissues overrides the supply from the tracheal respiratory system, which principally grows only at moults. Support for the ODIM hypothesis is controversial, partly because of a lack of proper data to explicitly test the hypothesis. The ODIM hypothesis predicts that the critical mass is positively correlated with oxygen partial pressure ( P O 2 ) and negatively with temperature. To resolve the controversy that surrounds the ODIM hypothesis, we rigorously test these predictions by exposing penultimate-instar Orthosia gothica (Lepidoptera: Noctuidae) larvae to temperature and moderate P O 2  manipulations in a factorial experiment. The relative mass increment in the focal instar increased along with increasing P O 2 , as predicted, but there was only weak suggestive evidence of the temperature effect. Probably owing to a high measurement error in the trait, the effect of P O 2  on the critical mass was sex specific; high P O 2  had a positive effect only in females, whereas low P O 2  had a negative effect only in males. Critical mass was independent of temperature. Support for the ODIM hypothesis is partial because of only suggestive evidence of a temperature effect on moulting, but the role of oxygen in moult induction seems unambiguous. The ODIM mechanism thus seems worth considering in body size analyses. © 2018. Published by The Company of Biologists Ltd.

Non-breeding Cackling, Ross's and Snow Geese on Baffin Island show no loss of body mass during wing moult

DEFF Research Database (Denmark)

Fox, Anthony David; Leafloor, James O.; Balsby, Thorsten Johannes Skovbjerg

2016-01-01

is consistent with the hypothesis that in other species of geese, accumulation of fat stores prior to, and depletion of such stores during, wing moult is adaptive and likely to be a feature of individual plasticity to meet particular needs, such as undertaking moult migration to remote sites where precise...

EFFECTS OF RATION SIZE AND TEMPERATURE ON MOULT INCREMENT AND METABOLIC PARAMETERS OF JUVENILE NOBLE CRAYFISH, ASTACUS ASTACUS

Directory of Open Access Journals (Sweden)

RENAI B.

2007-07-01

Full Text Available A laboratory experiment was carried out to test the combined effects of ration size (1 vs 3% body weight, b.w. and temperature (15 ± 2 vs 22 ± 2 °C on moult increment and metabolic parameters of 80 juvenile noble crayfish (Astacus astacus. The maximum daily consumption (Cmax and respiration rate (R were used to calculate the growth scope (i.e. the difference between maximum daily energy consumption and energy costs at a given temperature. The conversion of R into a food-equivalent unit allowed the comparison with Cmax. Results showed that crayfish obtained the maximum moult increment when fed 3% b.w. while temperature seemed to play a less relevant role on growth rate per moult, affecting only the moulting frequency. Crayfish A. astacus fed ad libitum showed a relative insensitivity to the metabolic parameters (oxygen uptake, R and Cmax within the analysed range of temperatures, possibly as a reflection of this “species” distribution across a broad variety of habitats with different thermal regimes. In the present study, A. astacus displayed characteristics proper of a K-selected species, as slow to moderate growth.

Effects of irradiation to larvae of Bombyx mori in relation to nutritional conditions and to moulting

International Nuclear Information System (INIS)

Coulon, M.

1976-01-01

Silkworms (Bombyx mori) were exposed to irradiation in the 1st and 2nd larval instars. The effects, as indicated by mortality or by failure to moult, were studied in relation to a period of starvation (24 hours at 22deg). Before the initiation of feeding, in either instar, the larvae were very resistant to irradiation and fasting did not modify this resistance. Probably this was due to physiological quiescence. After the initiation of feeding, the interposition of a fast either augmented or decreased radiation tolerance, probably according to the phase of the physiological cycle involving feeding and moulting

Transfer of 241Am and 237Pu from euphausiid moults to a carbonate-rich marine sediment

International Nuclear Information System (INIS)

Hargrave, B.T.

1986-01-01

Concentrations of 241 Am and 237 Pu adsorbed onto moulted exoskeletons from the euphausiid Meganyctiphanes norvegica decreased exponentially with 50% retention times of 3-7 d when moults were incubated in filtered seawater with small amounts of carbonate-rich sediment. Over 95% of sediment weight was present as -2 ) was greatest in the medium-fine sand fraction which had the highest carbonate content. These particles constituted -2 surface: atoms μm -3 in solution) was 10 3 -10 4 times higher than similar quotients for 241 Am and 237 Pu sorbed to surfaces of organic particles are transferred to sediments. (author)

Seven 365-Million-Year-Old Trilobites Moulting within a Nautiloid Conch

Science.gov (United States)

Zong, Rui-Wen; Fan, Ruo-Ying; Gong, Yi-Ming

2016-10-01

A nautiloid conch containing many disarticulated exoskeletons of Omegops cornelius (Phacopidae, Trilobita) was found in the Upper Devonian Hongguleleng Formation of the northwestern margin of the Junggar Basin, NW China. The similar number of cephala, thoraces and pygidia, unbroken thoraces, explicit exuviae, and lack of other macrofossils in the conch, indicate that at least seven individual trilobites had moulted within the nautiloid living chamber, using the vacant chamber of a dead nautiloid as a communal place for ecdysis. This exuvial strategy manifests cryptic behaviour of trilobites, which may have resulted from the adaptive evolution induced by powerful predation pressure, unstable marine environments, and competition pressure of organisms occupying the same ecological niche in the Devonian period. The unusual presence of several trilobites moulting within a nautiloid conch is possibly associated with social behaviours in face of a serious crisis. New materials in this study open a window for understanding the survival strategy of marine benthic organisms, especially predator-prey interactions and the behavioural ecology of trilobites in the middle Palaeozoic.

Candidate genes have sex-specific effects on timing of spring migration and moult speed in a long-distance migratory bird.

Science.gov (United States)

Bazzi, Gaia; Podofillini, Stefano; Gatti, Emanuele; Gianfranceschi, Luca; Cecere, Jacopo G; Spina, Fernando; Saino, Nicola; Rubolini, Diego

2017-10-01

The timing of major life-history events, such as migration and moult, is set by endogenous circadian and circannual clocks, that have been well characterized at the molecular level. Conversely, the genetic sources of variation in phenology and in other behavioral traits have been sparsely addressed. It has been proposed that inter-individual variability in the timing of seasonal events may arise from allelic polymorphism at phenological candidate genes involved in the signaling cascade of the endogenous clocks. In this study of a long-distance migratory passerine bird, the willow warbler Phylloscopus trochilus , we investigated whether allelic variation at 5 polymorphic loci of 4 candidate genes ( Adcyap1 , Clock , Creb1 , and Npas2 ), predicted 2 major components of the annual schedule, namely timing of spring migration across the central Mediterranean sea and moult speed, the latter gauged from ptilochronological analyses of tail feathers moulted in the African winter quarters. We identified a novel Clock gene locus ( Clock region 3) showing polyQ polymorphism, which was however not significantly associated with any phenotypic trait. Npas2 allele size predicted male (but not female) spring migration date, with males bearing longer alleles migrating significantly earlier than those bearing shorter alleles. Creb1 allele size significantly predicted male (but not female) moult speed, longer alleles being associated with faster moult. All other genotype-phenotype associations were statistically non-significant. These findings provide new evidence for a role of candidate genes in modulating the phenology of different circannual activities in long-distance migratory birds, and for the occurrence of sex-specific candidate gene effects.

A clip domain serine protease involved in moulting in the silkworm, Bombyx mori: cloning, characterization, expression patterns and functional analysis.

Science.gov (United States)

Liu, H-W; Wang, L-L; Meng, Z; Tang, X; Li, Y-S; Xia, Q-Y; Zhao, P

2017-10-01

Clip domain serine proteases (CLIPs), characterized by one or more conserved clip domains, are essential components of extracellular signalling cascades in various biological processes, especially in innate immunity and the embryonic development of insects. Additionally, CLIPs may have additional non-immune functions in insect development. In the present study, the clip domain serine protease gene Bombyx mori serine protease 95 (BmSP95), which encodes a 527-residue protein, was cloned from the integument of B. mori. Bioinformatics analysis indicated that BmSP95 is a typical CLIP of the subfamily D and possesses a clip domain at the N terminus, a trypsin-like serine protease (tryp_spc) domain at the C terminus and a conserved proline-rich motif between these two domains. At the transcriptional level, BmSP95 is expressed in the integument during moulting and metamorphosis, and the expression pattern is consistent with the fluctuating 20-hydroxyecdysone (20E) titre in B. mori. At the translational level, BmSP95 protein is synthesized in the epidermal cells, secreted as a zymogen and activated in the moulting fluid. Immunofluorescence revealed that BmSP95 is distributed into the old endocuticle in the moulting stage. The expression of BmSP95 was upregulated by 20E. Moreover, expression of BmSP95 was downregulated by pathogen infection. RNA interference-mediated silencing of BmSP95 led to delayed moulting from pupa to moth. These results suggest that BmSP95 is involved in integument remodelling during moulting and metamorphosis. © 2017 The Royal Entomological Society.

Isotope signatures in winter moulted feathers predict malaria prevalence in a breeding avian host.

Science.gov (United States)

Yohannes, Elizabeth; Hansson, Bengt; Lee, Raymond W; Waldenström, Jonas; Westerdahl, Helena; Akesson, Mikael; Hasselquist, Dennis; Bensch, Staffan

2008-11-01

It is widely accepted that animal distribution and migration strategy might have co-evolved in relation to selection pressures exerted by parasites. Here, we first determined the prevalence and types of malaria blood parasites in a breeding population of great reed warblers Acrocephalus arundinaceus using PCR. Secondly, we tested for differences in individual feather stable isotope signatures (delta (13)C, delta (15)N, deltaD and delta (34)S) to investigate whether malaria infected and non-infected birds had occupied different areas in winter. We show that birds moulting in Afro-tropical habitats with significantly higher delta (13)C and delta (15)N but lower deltaD and delta(34)S values were more frequently infected with malaria parasites. Based on established patterns of isotopic distributions, our results indicate that moulting sites with higher incidence of malaria are generally drier and situated further to the north in West Africa than sites with lower incidence of malaria. Our findings are pertinent to the general hypothesis that animal distribution and particularly avian migration strategy might evolve in response to selection pressures exerted by parasites at different geographic scales. Tradeoffs between investment in energy demanding life history traits (e.g. migration and winter moult) and immune function are suggested to contribute to the particular choice of habitat during migration and at wintering sites.

Effects of two PBDE congeners on the moulting enzymes of the freshwater amphipod Gammarus pulex

International Nuclear Information System (INIS)

Gismondi, Eric; Thomé, Jean-Pierre

2014-01-01

Polybrominated diphenyl ethers (PBDEs) are abundant in aquatic environment. However, only few studies have investigated their impacts on freshwater invertebrates. This work aimed to study the effects of BDE-47 and BDE-99 congeners on the chitobiase and chitinolytic enzymes activities of the freshwater amphipod Gammarus pulex, according to gender, PBDE concentration and time of exposure. In addition, the bioaccumulation of BDE-47 and BDE-99 were measured. Results revealed that females have bioaccumulated more PBDE than males, and BDE-99 was more accumulated than BDE-47. PBDE exposures for 96 h have caused chitobiase and chitinolytic enzymes inhibition. This study not only indicate the importance of taking into account various confounding factors (gender, congeners, concentration) to understand PBDE effects, but underline also disruptions of molting enzymes activities. These disturbances suggest effects on the gammarid development and reproduction, and consequently effects on the gammarid population, and on a larger scale, a dysfunction of the ecosystem. - Highlights: • G. pulex females bioaccumulate more PBDE than males. • PBDE exposure increases enzyme activities involved in moult process. • Gammarid gender, PBDE congener and concentration are confounding factors. - BDE-47 and BDE-99 are accumulated in Gammarus pulex males and females and have impacted the moulting process, since they influenced the moult enzymes activities

PENGARUH PEMBERIAN EKSTRAK PAKIS SEBAGAI MOULTING STIMULAN PADA INDUK UDANG WINDU (Penaeus monodon. Fab DI HATCHERY

Directory of Open Access Journals (Sweden)

Emma Suryati

2013-08-01

kandungan senyawa steroid yaitu fitoekdisteroid dalam bentuk 20-Hydroxyecdyson atau Ecdysteron berfungsi sebagai moulting stimulan pada krustase. Pada umumnya ecdysteron ditemukan pada krustase baik yang ada di darat maupun yang berada di dalam air seperti kepiting, udang, dan krustase lainnya yang ditemukan secara alami dan berfungsi sebagai pengatur proses penggantian kulit dan mengontrol pembentukan exoskeleton baru untuk menggantikan exoskeleton yang lama. Selain ablasi proses moulting pada udang dapat diinduksi melalui penambahan 20-hydroksi ecdysteron (20 E pada hemolim sehingga fase premoulting dapat diatur sesuai dengan kebutuhan. 20-hydroksiecdysteron dapat diperoleh dari ekstrak tumbuhan di antaranya bayam, asparagus, pakis, dan lain-lain melalui pemisahan dengan ekstraksi, fraksinasi, dan pemurnian dengan HPLC dilanjutkan dengan elusidasi struktur. Pemberian ekstrak pakis pada induk udang windu untuk memacu terjadinya pergantian kulit dilakukan melalui dengan beberapa konsentrasi menggunakan desain Rancangan Acak Lengkap (RAL. Hasil analisis memperlihatkan bahwa kandungan phytoecdysteron pada pakis perkisar 230-730 mg/L dari larutan ekstrak yang setara dengan 20 g bahan segar. Konsentrasi ECD 25 mg/L, memperlihatkan respon yang paling baik sebagai moulting stimulan.

Investigations on the metabolism of metals in decapod crustaceas in relation with moulting cycles and reproduction

International Nuclear Information System (INIS)

Martin, J.-L.M.

1975-07-01

A study of the metabolism of metals was carried out in decapod crustaceas; it showed that it was subject to cyclic variations during the life of the animals, closely correlated with growth moults. The metabolism of metals was also considered in its relations with reproduction, especially oogenesis and spermatogenesis, and embryonic development. In relation with moult, various factors playing a role on metal metabolism were investigated: role of metals in the organism, fasting and nutrition cycles and biochemical reserves, physico-chemical form of the metal and ultrastructure of uptake surfaces. The histological and histochemical aspects of the uptake of a number of metals were studied as well as inter-metallic and inter-organic relationships [fr

Effects of starvation on moult cycle and hepatopancreas of Stage I lobster (Homarus americanus) larvae

Science.gov (United States)

Anger, K.; Storch, V.; Anger, V.; Capuzzo, J. M.

1985-06-01

Effects of feeding and starvation on the moult cycle and on the ultrastructure of hepatopancreas cells were studied in Stage I lobster larvae ( Homarus americanus Milne-Edwards). The relative significance of yolk and first food was quite different in larvae originating from two females. This difference was evident also in the amounts of stored lipid in the R-cells of the larval hepatopancreas. Most larvae from one hatch were, in principle, able to develop exclusively with yolk reserves (without food) to the second instar. The larvae from the second hatch showed lecithotrophic development only to the transition between late intermoult and early premoult (Stages C/D0 of Drachs's moult cycle) of the first larval instar. When initial starvation in this group lasted for 3 days or more, the point of no return (PNR) was exceeded. After the PNR, consumption of food was still possible, but development ceased in the transition C/D0 or in late premoult (D3 4). It is suggested that these stages of the moult cycle are critical points were cessation of development and increased mortality are particularly likely in early larval lobsters under nutritional stress. Examination of hepatopancreas R-cells suggested that the PNR is caused by an irreversible loss of the ability to restore lipid reserves depleted during initial starvation. Initial periods of starvation ending before the PNR prolonged mainly Stage D0 of the same instar (I). During this delay, structural changes in the R-cells caused by the preceding period of starvation were reversed: reduced lipid inclusions, swollen mitochondria, an increased number of residual bodies indicating autolysis, and a reduction of the microvillous processes. Continually starved larvae which showed lecithotrophic development throughout the first instar and were then re-fed after moulting successfully, had later a prolonged intermoult (Stage C) period in the second instar. This shows that, despite occasional lecithotrophy, food is an important

Seven 365-Million-Year-Old Trilobites Moulting within a Nautiloid Conch

OpenAIRE

Zong, Rui-Wen; Fan, Ruo-Ying; Gong, Yi-Ming

2016-01-01

A nautiloid conch containing many disarticulated exoskeletons of Omegops cornelius (Phacopidae, Trilobita) was found in the Upper Devonian Hongguleleng Formation of the northwestern margin of the Junggar Basin, NW China. The similar number of cephala, thoraces and pygidia, unbroken thoraces, explicit exuviae, and lack of other macrofossils in the conch, indicate that at least seven individual trilobites had moulted within the nautiloid living chamber, using the vacant chamber of a dead nautil...

Transcriptome analysis on the exoskeleton formation in early developmetal stages and reconstruction scenario in growth-moulting in Litopenaeus vannamei.

Science.gov (United States)

Gao, Yi; Wei, Jiankai; Yuan, Jianbo; Zhang, Xiaojun; Li, Fuhua; Xiang, Jianhai

2017-04-24

Exoskeleton construction is an important issue in shrimp. To better understand the molecular mechanism of exoskeleton formation, development and reconstruction, the transcriptome of the entire developmental process in Litopenaeus vannamei, including nine early developmental stages and eight adult-moulting stages, was sequenced and analysed using Illumina RNA-seq technology. A total of 117,539 unigenes were obtained, with 41.2% unigenes predicting the full-length coding sequence. Gene Ontology, Clusters of Orthologous Group (COG), the Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis and functional annotation of all unigenes gave a better understanding of the exoskeleton developmental process in L. vannamei. As a result, more than six hundred unigenes related to exoskeleton development were identified both in the early developmental stages and adult-moulting. A cascade of sequential expression events of exoskeleton-related genes were summarized, including exoskeleton formation, regulation, synthesis, degradation, mineral absorption/reabsorption, calcification and hardening. This new insight on major transcriptional events provide a deep understanding for exoskeleton formation and reconstruction in L. vannamei. In conclusion, this is the first study that characterized the integrated transcriptomic profiles cover the entire exoskeleton development from zygote to adult-moulting in a crustacean, and these findings will serve as significant references for exoskeleton developmental biology and aquaculture research.

[Phylogeny of protostome moulting animals (Ecdysozoa) inferred from 18 and 28S rRNA gene sequences].

Science.gov (United States)

Petrov, N B; Vladychenskaia, N S

2005-01-01

Reliability of reconstruction of phylogenetic relationships within a group of protostome moulting animals was evaluated by means of comparison of 18 and 28S rRNA gene sequences sets both taken separately and combined. Reliability of reconstructions was evaluated by values of the bootstrap support of major phylogenetic tree nodes and by degree of congruence of phylogenetic trees inferred by various methods. By both criteria, phylogenetic trees reconstructed from the combined 18 and 28S rRNA gene sequences were better than those inferred from 18 and 28S sequences taken separately. Results obtained are consistent with phylogenetic hypothesis separating protostome animals into two major clades, moulting Ecdysozoa (Priapulida + Kinorhyncha, Nematoda + Nematomorpha, Onychophora + Tardigrada, Myriapoda + Chelicerata, Crustacea + Hexapoda) and unmoulting Lophotrochozoa (Plathelminthes, Nemertini, Annelida, Mollusca, Echiura, Sipuncula). Clade Cephalorhyncha does not include nematomorphs (Nematomorpha). Conclusion was taken that it is necessary to use combined 18 and 28S data in phylogenetic studies.

Effects of acute change in salinity and moulting on the infection of white leg shrimp (Penaeus vannamei) with white spot syndrome virus upon immersion challenge.

Science.gov (United States)

Van Thuong, K; Van Tuan, V; Li, W; Sorgeloos, P; Bossier, P; Nauwynck, H

2016-12-01

In the field, moulting and salinity drop in the water due to excessive rainfall have been mentioned to be risk factors for WSSV outbreaks. Therefore, in this study, the effect of an acute change in environmental salinity and shedding of the old cuticle shell on the susceptibility of Penaeus vannamei to WSSV was evaluated by immersion challenge. For testing the effect of abrupt salinity stress, early premoult shrimp that were acclimated to 35 g L -1 were subjected to salinities of 50 g L -1 , 35 g L -1 , 20 g L -1 , 10 g L -1 and 7 g L -1 or 5 g L -1 and simultaneously exposed to 10 5.5  SID 50 mL -1 of WSSV for 5 h, after which the salinity was brought back to 35 g L -1 . Shrimp that were transferred from 35 g L -1 to 50 g L -1 , 35 g L -1 and 20 g L -1 did not become infected with WSSV. Shrimp became infected with WSSV after an acute salinity drop from 35 g L -1 to 10 g L -1 and lower. The mortality in shrimp, subjected to a salinity change to 10 g L -1 , 7 g L -1 and 5 g L -1 , was 6.7%, 46.7% and 53.3%, respectively (P shrimp in early premoult, moulting and post-moult were immersed in sea water containing 10 5.5  SID 50 mL -1 of WSSV. The resulting mortality due to WSSV infection in shrimp inoculated during early premoult (0%), ecdysis (53.3%) and post-moult (26.72%) demonstrated that a significant difference exists in susceptibility of shrimp during the short moulting process (P shrimp are at risk for a WSSV infection. These findings have important implications for WSSV control measures. © 2016 John Wiley & Sons Ltd.

Flight performance and feather quality: paying the price of overlapping moult and breeding in a tropical highland bird.

Directory of Open Access Journals (Sweden)

Maria Angela Echeverry-Galvis

Full Text Available A temporal separation of energetically costly life history events like reproduction and maintenance of the integumentary system is thought to be promoted by selection to avoid trade-offs and maximize fitness. It has therefore remained somewhat of a paradox that certain vertebrate species can undergo both events simultaneously. Identifying potential costs of overlapping two demanding life history stages will further our understanding of the selection pressures that shape the temporal regulation of life history events in vertebrates. We studied free-living tropical Slaty brush-finches (Atlapetes schistaceus, in which individuals spontaneously overlap reproduction and moult or undergo both events in separation. To assess possible costs of such an overlap we quantified feather quality and flight performance of individuals in different states. We determined individual's life history state by measuring gonad size and scoring moult stage, and collected a newly grown 7(th primary wing feather for later analysis of feather quality. Finally, we quantified flight performance for each individual in the wild. Overlapping individuals produced lighter and shorter wing feathers than individuals just moulting, with females decreasing feather quality more strongly during the overlap than males. Moreover, overlapping individuals had a reduced flight speed during escape flights, while their foraging flight speed was unaffected. Despite overlappers being larger and having a smaller wing area, their lower body mass resulted in a similar wing load as in breeders or moulters. Individuals measured repeatedly in different states also showed significant decreases in feather quality and escape flight speed during the overlap. Reduced escape flight speed may represent a major consequence of the overlap by increasing predation risk. Our data document costs to undergoing two life history stages simultaneously, which likely arise from energetic trade-offs. Impairments in

Association between cadmium and calcium uptake and distribution during the moult cycle of female shore crabs, Carcinus maenas: an in vivo study

International Nuclear Information System (INIS)

Bondgaard, Morten; Bjerregaard, Poul

2005-01-01

Net influxes into the haemolymph and tissue distribution of 45 Ca and 109 Cd were studied in vivo in female Carcinus maenas at different moult stages. Net influxes of 45 Ca and 109 Cd from water were higher in postmoult (A and B) C. maenas than in C 3 - and C 4 -intermoult crabs and the net influx of calcium was higher in C 3 -intermoult crabs than in C 4 -intermoult crabs. The net influxes of 45 Ca and 109 Cd increased in postmoult C. maenas with decreasing external calcium concentrations at constant salinity. At all external calcium concentrations a significant correlation existed between 45 Ca and 109 Cd accumulated in the haemolymph of individual animals. In vivo exposure of postmoult C. maenas to external lanthanum decreased the 45 Ca and 109 Cd uptake rates to 30 and 10%, respectively, of the control values. About 30% of injected 109 Cd were found in the midgut gland, 10-20% in the gills and only a few (1-2) percent was lost to the seawater 24 h after injection. No major variations in tissue distribution of 109 Cd were observed between moult stages in these tissues. Premoult crabs retained more cadmium in the haemolymph 24 h after injection than other moult stages, and postmoult crabs retained more in muscle. Between 20 and 40% of the injected 45 Ca were excreted to the water, while only a few percent of the injected 45 Ca were found in the soft tissues 24 h after injection. Large moult stage variations, however, were observed in the tissue distribution of internalised 45 Ca. This study demonstrates that cadmium and calcium uptakes are elevated in postmoult C. maenas. The results indicate that cadmium and calcium in this stage are taken up via Ca 2+ -channels located in the apical membrane of gill epithelium cells. When internalised, however, cadmium and calcium are metabolised in fundamentally different ways, determined by the chemical properties and biological significance of the two metals

High level efficacy of lufenuron against sea lice (Lepeophtheirus salmonis) linked to rapid impact on moulting processes.

Science.gov (United States)

Poley, Jordan D; Braden, Laura M; Messmer, Amber M; Igboeli, Okechukwu O; Whyte, Shona K; Macdonald, Alicia; Rodriguez, Jose; Gameiro, Marta; Rufener, Lucien; Bouvier, Jacques; Wadowska, Dorota W; Koop, Ben F; Hosking, Barry C; Fast, Mark D

2018-03-13

Drug resistance in the salmon louse Lepeophtheirus salmonis is a global issue for Atlantic salmon aquaculture. Multiple resistance has been described across most available compound classes with the exception of the benzoylureas. To target this gap in effective management of L. salmonis and other species of sea lice (e.g. Caligus spp.), Elanco Animal Health is developing an in-feed treatment containing lufenuron (a benzoylurea) to be administered prior to seawater transfer of salmon smolts and to provide long-term protection of salmon against sea lice infestations. Benzoylureas disrupt chitin synthesis, formation, and deposition during all moulting events. However, the mechanism(s) of action are not yet fully understood and most research completed to date has focused on insects. We exposed the first parasitic stage of L. salmonis to 700 ppb lufenuron for three hours and observed over 90% reduction in survival to the chalimus II life stage on the host, as compared to vehicle controls. This agrees with a follow up in vivo administration study on the host, which showed >95% reduction by the chalimus I stage. Transcriptomic responses of salmon lice exposed to lufenuron included genes related to moulting, epithelial differentiation, solute transport, and general developmental processes. Global metabolite profiles also suggest that membrane stability and fluidity is impacted in treated lice. These molecular signals are likely the underpinnings of an abnormal moulting process and cuticle formation observed ultrastructurally using transmission electron microscopy. Treated nauplii-staged lice exhibited multiple abnormalities in the integument, suggesting that the coordinated assembly of the epi- and procuticle is impaired. In all cases, treatment with lufenuron had rapid impacts on L. salmonis development. We describe multiple experiments to characterize the efficacy of lufenuron on eggs, larvae, and parasitic stages of L. salmonis, and provide the most comprehensive

Mineral in skeletal elements of the terrestrial crustacean Porcellio scaber: SR mu CT of function related distribution and changes during the moult cycle

Czech Academy of Sciences Publication Activity Database

Ziegler, A.; Neues, F.; Janáček, Jiří; Beckmann, F.; Epple, M.

2017-01-01

Roč. 46, č. 1 (2017), s. 63-76 ISSN 1467-8039 Institutional support: RVO:67985823 Keywords : crustacea * isopoda * mineral * moult * oniscidea * synchrotron-radiation microtomography Subject RIV: EA - Cell Biology OBOR OECD: Developmental biology Impact factor: 1.546, year: 2016

Transcriptome analysis on the exoskeleton formation in early developmetal stages and reconstruction scenario in growth-moulting in Litopenaeus vannamei

OpenAIRE

Yi Gao; Jiankai Wei; Jianbo Yuan; Xiaojun Zhang; Fuhua Li; Jianhai Xiang

2017-01-01

Exoskeleton construction is an important issue in shrimp. To better understand the molecular mechanism of exoskeleton formation, development and reconstruction, the transcriptome of the entire developmental process in Litopenaeus vannamei, including nine early developmental stages and eight adult-moulting stages, was sequenced and analysed using Illumina RNA-seq technology. A total of 117,539 unigenes were obtained, with 41.2% unigenes predicting the full-length coding sequence. Gene Ontology...

Effect of calcium with and without probiotic, lactose, or both on organ and body weights, immune response and caecal microbiota in moulted laying hens.

Science.gov (United States)

Dastar, B; Khosravi, A; Boldajie, F; Ghoorchi, T

2016-04-01

A total of 72 laying hens were used to investigate the effect of probiotic and lactose on body weight loss, tibia ash, antibody production against sheep red blood cell (SRBC), heterophile-to-lymphocyte (H/L) ratio and gut microbiota in a common moulting method for 14 d. Hens were randomly allocated to 6 experimental groups consisting of (i) full feed (FF), (ii) feed withdrawal (FW), (iii) FW with calcium (Ca), (iv) FW with Ca and offering 7 g/lit lactose in drinking water (CaL), (v) FW with Ca and offering 1 g/lit probiotic in drinking water (CaP), and (vi) FW with Ca and offering a mixture of lactose and probiotic in drinking water (CaLP). The results showed body weight loss in all FW groups were more than 25% that was significantly higher than FF group (p lactose numerically and probiotic alone significantly resulted in decrease of this ratio (p lactose could significantly reduce this population (p lactose was effective in maintaining caecal microbiota balance and improving immunity in hens exposed to moulting. Journal of Animal Physiology and Animal Nutrition © 2015 Blackwell Verlag GmbH.

In vivo and in vitro cadmium accumulation during the moult cycle of the male shore crab Carcinus maenas-interaction with calcium metabolism

International Nuclear Information System (INIS)

Norum, Ulrik; Bondgaard, Morten; Pedersen, Thomas V.; Bjerregaard, Poul

2005-01-01

The effect of moult stage on cadmium accumulation and distribution was investigated in vivo in male shore crabs Carcinus maenas exposed to 1 mg Cd l -1 for 7 days. The accumulation of cadmium in all tissues examined was markedly higher in postmoult (A 1-2 and B 1-2 ) compared to intermoult (C 1 , C 3 and C 4 ) and premoult (D 0-3 ). In addition, elevated levels of cadmium were found in gills of late premoult (D 2-3 ) animals. The total amount of cadmium accumulated in the tissues (haemolymph, gills, midgut gland and muscle) increased from 43 μg Cd in early premoult (D 0-1 ) to 391 μg Cd in late postmoult (B 1-2 ). Gills and midgut gland were the primary cadmium accumulating tissues in C 4 -intermoult and premoult (D 0-3 ); in early postmoult (A 1-2 ) haemolymph and midgut gland were the main cadmium containing tissues, while midgut gland dominated in late postmoult (B 1-2 ) and early intermoult (C 1 and C 3 ). A detailed account of calcium distribution in haemolymph, gills, midgut gland, muscle and exoskeleton during the moult cycle is presented. Mechanistic links between cadmium and calcium uptake in posterior gills of C 4 -intermoult and early postmoult (A 1-2 ) crabs were explored using an in vitro gill perfusion technique. Calcium and cadmium influxes were markedly higher in postmoult compared to intermoult. No differences between intermoult and postmoult effluxes were found for either calcium or cadmium. From intermoult to postmoult net influx increased from 2.4 to 29 μmol Ca 2+ g -1 ww gill h -1 and from 0.24 to 25 nmol Cd 2+ g -1 ww gill h -1 . The results indicate that the postmoult increase in cadmium influx is due to increased active transport of cadmium, at least partly, by accidental uptake via calcium transporting proteins. The in vitro net influx rates corresponded accurately to the observed in vivo accumulation of both cadmium and calcium. Although cadmium accumulation and distribution are clearly linked to changes in calcium requirements, cadmium

In vivo and in vitro cadmium accumulation during the moult cycle of the male shore crab Carcinus maenas-interaction with calcium metabolism

Energy Technology Data Exchange (ETDEWEB)

Norum, Ulrik [Institute of Biology, University of Southern Denmark, Campusvej 55, DK-5230 Odense M (Denmark)]. E-mail: ulrik@biology.sdu.dk; Bondgaard, Morten [Institute of Biology, University of Southern Denmark, Campusvej 55, DK-5230 Odense M (Denmark); Pedersen, Thomas V. [Institute of Biology, University of Southern Denmark, Campusvej 55, DK-5230 Odense M (Denmark); Bjerregaard, Poul [Institute of Biology, University of Southern Denmark, Campusvej 55, DK-5230 Odense M (Denmark)

2005-03-25

The effect of moult stage on cadmium accumulation and distribution was investigated in vivo in male shore crabs Carcinus maenas exposed to 1 mg Cd l{sup -1} for 7 days. The accumulation of cadmium in all tissues examined was markedly higher in postmoult (A{sub 1-2} and B{sub 1-2}) compared to intermoult (C{sub 1}, C{sub 3} and C{sub 4}) and premoult (D{sub 0-3}). In addition, elevated levels of cadmium were found in gills of late premoult (D{sub 2-3}) animals. The total amount of cadmium accumulated in the tissues (haemolymph, gills, midgut gland and muscle) increased from 43 {mu}g Cd in early premoult (D{sub 0-1}) to 391 {mu}g Cd in late postmoult (B{sub 1-2}). Gills and midgut gland were the primary cadmium accumulating tissues in C{sub 4}-intermoult and premoult (D{sub 0-3}); in early postmoult (A{sub 1-2}) haemolymph and midgut gland were the main cadmium containing tissues, while midgut gland dominated in late postmoult (B{sub 1-2}) and early intermoult (C{sub 1} and C{sub 3}). A detailed account of calcium distribution in haemolymph, gills, midgut gland, muscle and exoskeleton during the moult cycle is presented. Mechanistic links between cadmium and calcium uptake in posterior gills of C{sub 4}-intermoult and early postmoult (A{sub 1-2}) crabs were explored using an in vitro gill perfusion technique. Calcium and cadmium influxes were markedly higher in postmoult compared to intermoult. No differences between intermoult and postmoult effluxes were found for either calcium or cadmium. From intermoult to postmoult net influx increased from 2.4 to 29 {mu}mol Ca{sup 2+} g{sup -1} ww{sub gill} h{sup -1} and from 0.24 to 25 nmol Cd{sup 2+} g{sup -1} ww{sub gill} h{sup -1}. The results indicate that the postmoult increase in cadmium influx is due to increased active transport of cadmium, at least partly, by accidental uptake via calcium transporting proteins. The in vitro net influx rates corresponded accurately to the observed in vivo accumulation of both cadmium

Copepod egg production, moulting and growth rates and secondary production in the Skagerrak in August 1988

DEFF Research Database (Denmark)

Peterson, W.T.; Tiselius, P.; Kiørboe, Thomas

1991-01-01

Measurements of hydrography, chlorophyll, moulting rates of juvenile copepods and egg production rates of adult female copepods were made at eight stations along a transect across the Skagerrak. The goals of the study were to determine (i) if there were correlations between spatial variations...... in hydrography, phytoplankton and copepod production rates, (ii) if copepod egg production rates were correlated with juvenile growth rates, and (iii) if there was evidence of food-niche separation among co-occurring female copepods. The 200 km wide Skagerrak had a stratified water column in the center...... is similar to maximum rates known from laboratory studies, thus were probably not food-limited. Egg production rates were food-limited with the degree of limitation varying among species: 75% of maximum for Centropages typicus, 50% for Calanus finmarchicus, 30% for Paracalanus parvus and 15% for Acartia...

Variations in ecdysteroid levels and cytochrome P450 expression during moult and reproduction in male shore crabs Carcinus maenas

DEFF Research Database (Denmark)

Styrishave, B.; Rewitz, K.; Lund, T.

2004-01-01

and intermoult. In the testis, 20E and E were present at high levels except in Postmoult Stage A, where low levels were observed. PoA was never observed in the testis. Ecdysteroids were quantified in the red and green colour forms of late intermoult C-4 crabs. In both phenotypes, 20E was the dominating...... had significantly higher testicular E levels than red crabs. Ecdysteroid levels were negatively related to CYP330A1 and CYP4C39 gene expression. CYP330A1 and CYP4C39 mRNA levels were low during intermoult and premoult but high during postmoult. The results suggest that E and 20E are involved in both......Ecdysteroid levels were investigated by HPLC-MS over the moult cycle and in relation to reproduction in male shore crabs Carcinus maenas. Ecdysone (E), 20-hydroxyecdysone (20E) and Ponasterone A (PoA) were quantified in the haemolymph, hepatopancreas and testis. Also, the expression of 2 recently...

Hand-rearing, release and survival of African penguin chicks abandoned before independence by moulting parents.

Science.gov (United States)

Sherley, Richard B; Waller, Lauren J; Strauss, Venessa; Geldenhuys, Deon; Underhill, Les G; Parsons, Nola J

2014-01-01

The African penguin Spheniscus demersus has an 'Endangered' conservation status and a decreasing population. Following abandonment, 841 African penguin chicks in 2006 and 481 in 2007 were admitted to SANCCOB (Southern African Foundation for the Conservation of Coastal Birds) for hand-rearing from colonies in the Western Cape, South Africa, after large numbers of breeding adults commenced moult with chicks still in the nest. Of those admitted, 91% and 73% respectively were released into the wild. There were veterinary concerns about avian malaria, airsacculitis and pneumonia, feather-loss and pododermatitis (bumblefoot). Post-release juvenile (0.32, s.e.  = 0.08) and adult (0.76, s.e.  = 0.10) survival rates were similar to African penguin chicks reared after oil spills and to recent survival rates recorded for naturally-reared birds. By December 2012, 12 birds had bred, six at their colony of origin, and the apparent recruitment rate was 0.11 (s.e.  = 0.03). Hand-rearing of abandoned penguin chicks is recommended as a conservation tool to limit mortality and to bolster the population at specific colonies. The feasibility of conservation translocations for the creation of new colonies for this species using hand-reared chicks warrants investigation. Any such programme would be predicated on adequate disease surveillance programmes established to minimise the risk of disease introduction to wild birds.

Evaluation of different marking methods for spiny-cheek crayfish (Orconectes limosus

Directory of Open Access Journals (Sweden)

Buřič M.

2008-10-01

Full Text Available Different methods of marking were evaluated for Orconectes limosus (CL = carapace length, 12–37 mm under laboratory conditions: the use of passive integrated transponders, visible implant elastomers, visible implant alphanumeric tags, and cauterization. High survival (> 90% was obtained with all methods tested. Tag retention and readability were evaluated immediately after marking, before and after ecdysis, with moult increments and number of moults been recorded. Marking using cauterization negatively affects the percent moult increment (PMI of crayfish. The average PMI of 15 ± 0.88% did not differ between males (15 ± 1.41 mm and females (15 ± 1.12 mm. It was found that PMI gradually decreased with an increase in CL. Sixty-one moults were observed, with 12 crayfish (6 juveniles and 6 adults presenting two moults. Time between moults varied from 3 to 7 weeks. CL was increased with over 28 ± 2.68% due to two moults. Three females moulted twice after successful hatching and carrying of juveniles.

Plumage quality mediates a life-history trade-off in a migratory bird.

Science.gov (United States)

Podlaszczuk, Patrycja; Kamiński, Maciej; Włodarczyk, Radosław; Kaczmarek, Krzysztof; Janiszewski, Tomasz; Minias, Piotr

2016-01-01

Moult is one of the most costly activities in the annual cycle of birds and most avian species separate moult from other energy-demanding activities, such as migration. To this end, young birds tend to undergo the first post-juvenile moult before the onset of migration, but in some species the time window for the pre-migratory feather replacement is too narrow. We hypothesized that in such species an increased investment in the structural quality of juvenile feathers may allow to retain juvenile plumage throughout the entire migratory period and delay moult until arriving at wintering grounds, thus avoiding a moult-migration overlap. The effect of juvenile plumage quality on the occurrence of moult-migration overlap was studied in a migratory shorebird, the common snipe Gallinago gallinago . Ca. 400 of first-year common snipe were captured during their final stage of autumn migration through Central Europe. The quality of juvenile feathers was assessed as the mass-length residuals of retained juvenile rectrices. Condition of migrating birds was assessed with the mass of accumulated fat reserves and whole-blood hemoglobin concentration. Path analysis was used to disentangle complex interrelationships between plumage quality, moult and body condition. Snipe which grew higher-quality feathers in the pre-fledging period were less likely to initiate moult during migration. Individuals moulting during migration had lower fat loads and hemoglobin concentrations compared to non-moulting birds, suggesting a trade-off in resource allocation, where energetic costs of moult reduced both energy reserves available for migration and resources available for maintenance of high oxygen capacity of blood. The results of this study indicate that a major life-history trade-off in a migratory bird may be mediated by the quality of juvenile plumage. This is consistent with a silver spoon effect, where early-life investment in feather quality affects future performance of birds during

Mud and silk in the dark

DEFF Research Database (Denmark)

P. S. Reboleira, Ana Sofia; Enghoff, Henrik

2016-01-01

chamber, using the available substrate reinforced by a silken web. We present the detailed ultrastructure of the moulting chamber and silk. It takes five days to build the moulting chamber and between 29 (female) and 35 (male) days to shed the exuviae. The male maturation moult is preceded...

Effects of ambient air temperature, humidity and rainfall on annual survival of adult little penguins Eudyptula minor in southeastern Australia

Science.gov (United States)

Ganendran, L. B.; Sidhu, L. A.; Catchpole, E. A.; Chambers, L. E.; Dann, P.

2016-08-01

Seabirds are subject to the influences of local climate variables during periods of land-based activities such as breeding and, for some species, moult; particularly if they undergo a catastrophic moult (complete simultaneous moult) as do penguins. We investigated potential relationships between adult penguin survival and land-based climate variables (ambient air temperature, humidity and rainfall) using 46 years of mark-recapture data of little penguins Eudyptula minor gathered at a breeding colony on Phillip Island in southeastern Australia. Our results showed that adult penguin survival had a stronger association with land-based climate variables during the moult period, when birds were unable to go to sea for up to 3 weeks, than during the breeding period, when birds could sacrifice breeding success in favour of survival. Annual adult survival probability was positively associated with humidity during moult and negatively associated with rainfall during moult. Prolonged heat during breeding and moult had a negative association with annual adult survival. Local climate projections suggest increasing days of high temperatures, fewer days of rainfall which will result in more droughts (and by implication, lower humidity) and more extreme rainfall events. All of these predicted climate changes are expected to have a negative impact on adult penguin survival.

Postlarval development of Halicarcinus planatus females (Crustacea, Decapoda, Hymenosomatidae in the estuary of the Deseado River, Argentina

Directory of Open Access Journals (Sweden)

Julio H. Vinuesa

2008-03-01

Full Text Available This study analyses morphology and morphometric growth changes of Halicarcinus planatus females until their terminal moult, and characterises new juvenile stages. Monthly samples were collected in the estuary of the Deseado River, Santa Cruz Province, Argentina. Crabs were sampled between the mid-intertidal and upper subtidal levels. Intermoult stages were analysed in sub-samples of adolescents and adults, and the presence of epizoic organisms was registered. Juveniles and adults were reared at the laboratory and examined for moult changes. All 3376 crabs caught were females, indicating a clear spatial segregation between sexes. Five juvenile stages (immature 1, 2, 3, 4 and adolescent and a mature one were recognised on the basis of morphology and morphometry. All immature stages differed in cephalothorax width (CW and abdomen width (AW. Positive allometry was observed in some juvenile stages and isometry in an immature stage and in mature females. Adolescents and adults encompassed a wide range of sizes, and the considerable size overlap between them suggests an anomalous growth process. Moult staging analysis indicated that adolescents have a high incidence of pre-moult stages in winter, when the terminal moult occurs. The measurements performed in laboratory-reared females indicated no abnormal increases during the moult. The terminal moult occurs within a wide size range, perhaps in association with mating.

Snowshoe hares display limited phenotypic plasticity to mismatch in seasonal camouflage

Science.gov (United States)

Zimova, Marketa; Mills, L. Scott; Lukacs, Paul M.; Mitchell, Michael S.

2014-01-01

As duration of snow cover decreases owing to climate change, species undergoing seasonal colour moults can become colour mismatched with their background. The immediate adaptive solution to this mismatch is phenotypic plasticity, either in phenology of seasonal colour moults or in behaviours that reduce mismatch or its consequences. We observed nearly 200 snowshoe hares across a wide range of snow conditions and two study sites in Montana, USA, and found minimal plasticity in response to mismatch between coat colour and background. We found that moult phenology varied between study sites, likely due to differences in photoperiod and climate, but was largely fixed within study sites with only minimal plasticity to snow conditions during the spring white-to-brown moult. We also found no evidence that hares modify their behaviour in response to colour mismatch. Hiding and fleeing behaviours and resting spot preference of hares were more affected by variables related to season, site and concealment by vegetation, than by colour mismatch. We conclude that plasticity in moult phenology and behaviours in snowshoe hares is insufficient for adaptation to camouflage mismatch, suggesting that any future adaptation to climate change will require natural selection on moult phenology or behaviour.

Accumulation of sup(95m)Tc from sea water by juvenile lobsters (Homarus gammarus L. )

Energy Technology Data Exchange (ETDEWEB)

Swift, D.J. (Ministry of Agriculture, Fisheries and Food, Lowestoft (UK). Directorate of Fisheries Research)

1985-01-01

The uptake and retention of technetium from sea water by juvenile lobsters, and the effects of moulting on these processes, has been studied using sup(95m)Tc as a tracer. Accumulation was rapid with whole body concentration factors of over 2000 being measured in some lobsters. Uptake was highest immediately before a moult; post-moult there was a fall in accumulation. No simple mathematical equation for technetium accumulation with time was found. The technetium concentration in the moulted exoskeleton increased with time of exposure of the lobsters but never exceeded 2% of the whole body value. The highest percentage of the whole body activity was found in the digestive gland; the green gland had the highest concentration factor. Technetium excretion, following 64 d of accumulation, could be expressed as an exponential rate of loss. The biological half-time was calculated as 53 d. Moulted exoskeletons from these lobsters contained approximately 0.6% of the day zero whole body activity.

The accumulation of sup(95m)Tc from sea water by juvenile lobsters (Homarus gammarus L.)

International Nuclear Information System (INIS)

Swift, D.J.

1985-01-01

The uptake and retention of technetium from sea water by juvenile lobsters, and the effects of moulting on these processes, has been studied using sup(95m)Tc as a tracer. Accumulation was rapid with whole body concentration factors of over 2000 being measured in some lobsters. Uptake was highest immediately before a moult; post-moult there was a fall in accumulation. No simple mathematical equation for technetium accumulation with time was found. The technetium concentration in the moulted exoskeleton increased with time of exposure of the lobsters but never exceeded 2% of the whole body value. The highest percentage of the whole body activity was found in the digestive gland; the green gland had the highest concentration factor. Technetium excretion, following 64 d of accumulation, could be expressed as an exponential rate of loss. The biological half-time was calculated as 53 d. Moulted exoskeletons from these lobsters contained approximately 0.6% of the day zero whole body activity. (author)

Cost-benefit analysis for invasive species control: the case of greater Canada goose Branta canadensis in Flanders (northern Belgium)

Science.gov (United States)

Casaer, Jim; De Smet, Lieven; Devos, Koen; Huysentruyt, Frank; Robertson, Peter A.; Verbeke, Tom

2018-01-01

Background Sound decisions on control actions for established invasive alien species (IAS) require information on ecological as well as socio-economic impact of the species and of its management. Cost-benefit analysis provides part of this information, yet has received relatively little attention in the scientific literature on IAS. Methods We apply a bio-economic model in a cost-benefit analysis framework to greater Canada goose Branta canadensis, an IAS with documented social, economic and ecological impacts in Flanders (northern Belgium). We compared a business as usual (BAU) scenario which involved non-coordinated hunting and egg destruction with an enhanced scenario based on a continuation of these activities but supplemented with coordinated capture of moulting birds. To assess population growth under the BAU scenario we fitted a logistic growth model to the observed pre-moult capture population. Projected damage costs included water eutrophication and damage to cultivated grasslands and were calculated for all scenarios. Management costs of the moult captures were based on a representative average of the actual cost of planning and executing moult captures. Results Comparing the scenarios with different capture rates, different costs for eutrophication and various discount rates, showed avoided damage costs were in the range of 21.15 M€ to 45.82 M€ under the moult capture scenario. The lowest value for the avoided costs applied to the scenario where we lowered the capture rate by 10%. The highest value occurred in the scenario where we lowered the real discount rate from 4% to 2.5%. Discussion The reduction in damage costs always outweighed the additional management costs of moult captures. Therefore, additional coordinated moult captures could be applied to limit the negative economic impact of greater Canada goose at a regional scale. We further discuss the strengths and weaknesses of our approach and its potential application to other IAS. PMID

Cost-benefit analysis for invasive species control: the case of greater Canada goose Branta canadensis in Flanders (northern Belgium

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Nikolaas Reyns

2018-01-01

Full Text Available Background Sound decisions on control actions for established invasive alien species (IAS require information on ecological as well as socio-economic impact of the species and of its management. Cost-benefit analysis provides part of this information, yet has received relatively little attention in the scientific literature on IAS. Methods We apply a bio-economic model in a cost-benefit analysis framework to greater Canada goose Branta canadensis, an IAS with documented social, economic and ecological impacts in Flanders (northern Belgium. We compared a business as usual (BAU scenario which involved non-coordinated hunting and egg destruction with an enhanced scenario based on a continuation of these activities but supplemented with coordinated capture of moulting birds. To assess population growth under the BAU scenario we fitted a logistic growth model to the observed pre-moult capture population. Projected damage costs included water eutrophication and damage to cultivated grasslands and were calculated for all scenarios. Management costs of the moult captures were based on a representative average of the actual cost of planning and executing moult captures. Results Comparing the scenarios with different capture rates, different costs for eutrophication and various discount rates, showed avoided damage costs were in the range of 21.15 M€ to 45.82 M€ under the moult capture scenario. The lowest value for the avoided costs applied to the scenario where we lowered the capture rate by 10%. The highest value occurred in the scenario where we lowered the real discount rate from 4% to 2.5%. Discussion The reduction in damage costs always outweighed the additional management costs of moult captures. Therefore, additional coordinated moult captures could be applied to limit the negative economic impact of greater Canada goose at a regional scale. We further discuss the strengths and weaknesses of our approach and its potential application to other

First record of Charadrius melodus Ord (Aves Charadriiformes in Brazil

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Azevedo Júnior Severino Mendes de

2003-01-01

Full Text Available Charadrius melodus Ord, 1824 were captured at Diamante Branco saline, at Galinhos municipal district in Rio Grande do Norte, at the Northeast coast of Brazil. Four individuals were captured in October and two in December. All of them were in adult phase, showing the intermediary plumage with moults of the outline feathers. One individual captured in October showed moult for the first primary pinion and other captured also in October showed moult in the second pair of rectrices. The captures of C. melodus in Rio Grande do Norte consist in the first record of the species for Brazil.

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Additionally, 551 orphaned chicks were collected at Robben Island, of which 508 were raised to “fledging” and released (Williams et al. in press). The probable explanation for the early moult of some adults in 1994/95 is that birds that are taken to the rescue station, cleaned and released commence moult earlier than usual.

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10 days coupled with 50 days of recovery period when the birds were fed low protein moult diet. ... In laying hens, the primary sources of progesterone are the granulosa cells of the five largest follicles in the hierarchy (Verheyen et al., 1987). These ovarian ..... cessation of egg laying induced by different moulting methods. J.

Moulting Black Holes

OpenAIRE

Bena, Iosif; Chowdhury, Borun D.; de Boer, Jan; El-Showk, Sheer; Shigemori, Masaki

2011-01-01

We find a family of novel supersymmetric phases of the D1-D5 CFT, which in certain ranges of charges have more entropy than all known ensembles. We also find bulk BPS configurations that exist in the same range of parameters as these phases, and have more entropy than a BMPV black hole; they can be thought of as coming from a BMPV black hole shedding a "hair" condensate outside of the horizon. The entropy of the bulk configurations is smaller than that of the CFT phases, which indicates that ...

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MARA SCHMIING

2009-01-01

Full Text Available Moulting, growth and retention of externally attached acoustic tags were studied in tenMediterranean slipper lobsters, Scyllarides latus (Latreille, 1802. Animals were kept in acage at 20 m depth in Faial Island, Azores, over a period of nine months. No negativeeffects of tag attachment on moult or behaviour were detected, but a negative effect on growth cannot be excluded. Moulting was correlated with ambient water temperature and resulted in an increase of approximately 7% in mean size and 17% in mean weight. The results demonstrate that the use of externally attached acoustic transmitters in this species is adequate for medium-term movement studies but not for longer-term annual studies, due to the rate of molting.

Characterization of an entomopathogenic fungi target integument protein, Bombyx mori single domain von Willebrand factor type C, in the silkworm, Bombyx mori.

Science.gov (United States)

Han, F; Lu, A; Yuan, Y; Huang, W; Beerntsen, B T; Huang, J; Ling, E

2017-06-01

The insect cuticle works as the first line of defence to protect insects from pathogenic infections and water evaporation. However, the old cuticle must be shed in order to enter the next developmental stage. During each ecdysis, moulting fluids are produced and secreted into the area among the old and new cuticles. In a previous study, the protein Bombyx mori single domain von Willebrand factor type C (BmSVWC; BGIBMGA011399) was identified in the moulting fluids of Bo. mori and demonstrated to regulate ecdysis. In this study we show that in Bo. mori larvae, BmSVWC primarily locates to the integument (epidermal cells and cuticle), wing discs and head. During the moulting stage, BmSVWC is released into the moulting fluids, and is then produced again by epidermal cells after ecdysis. Fungal infection was shown to decrease the amount of BmSVWC in the cuticle, which indicates that BmSVWC is a target protein of entomopathogenic fungi. Thus, BmSVWC is mainly involved in maintaining the integrity of the integument structure, which serves to protect insects from physical damage and pathogenic infection. © 2017 The Royal Entomological Society.

Effect of an insect juvenile hormone analogue, Fenoxycarb on development and oxygen uptake by larval lobsters Homarus gammarus (L.).

Science.gov (United States)

Arnold, Katie E; Wells, Colin; Spicer, John I

2009-04-01

Little attention has been focused on the effect of anthropogenic compounds that disrupt the endocrine systems in crustaceans. Consequently, this study investigated the effects of the juvenile hormone analogue (JHA), Fenoxycarb on selected physiological and developmental processes of the zoeal stages in the European lobster, Homarus gammarus. Chronic exposure to Fenoxycarb (50microg L(-1)) resulted in a significant (p < 0.05) reduction in moult frequency and size at moult. Fenoxycarb exposure extended zoeal duration between zoea I to II (p<0.05) and resulted in total inhibition of the moult from zoea II to III. Significantly greater rates of O2 uptake were observed in Fenoxycarb-exposed larvae in comparison with controls (p<0.05). All rates of O2 uptake decreased significantly between 7 and 12d of exposure (p<0.05). At 12d, exposure to the solvent control no longer influenced rates of O2 uptake, but it was not possible to attribute increased O2 uptake to Fenoxycarb exposure directly, as treated individuals did not moult beyond zoea III. The low exposure concentrations of Fenoxycarb, comparable to those used in plant protection, resulted in endocrine disrupted responses in H. gammarus (albeit with little clear, demonstrable effect on metabolism) a finding that could have important ecological and commercial implications.

Foraging and fasting can influence contaminant concentrations in animals: an example with mercury contamination in a free-ranging marine mammal

Science.gov (United States)

Peterson, Sarah; Ackerman, Joshua T.; Crocker, Daniel E.; Costa, Daniel P.

2018-01-01

Large fluctuations in animal body mass in relation to life-history events can influence contaminant concentrations and toxicological risk. We quantified mercury concentrations in adult northern elephant seals (Mirounga angustirostris) before and after lengthy at sea foraging trips (n = 89) or fasting periods on land (n = 27), and showed that mercury concentrations in blood and muscle changed in response to these events. The highest blood mercury concentrations were observed after the breeding fast, whereas the highest muscle mercury concentrations were observed when seals returned to land to moult. Mean female blood mercury concentrations decreased by 30% across each of the two annual foraging trips, demonstrating a foraging-associated dilution of mercury concentrations as seals gained mass. Blood mercury concentrations increased by 103% and 24% across the breeding and moulting fasts, respectively, demonstrating a fasting-associated concentration of mercury as seals lost mass. In contrast to blood, mercury concentrations in female's muscle increased by 19% during the post-breeding foraging trip and did not change during the post-moulting foraging trip. While fasting, female muscle mercury concentrations increased 26% during breeding, but decreased 14% during moulting. Consequently, regardless of exposure, an animal's contaminant concentration can be markedly influenced by their annual life-history events.

A Study of the Morphology and Biology of Thompsonia littoralis (Crustacea: Cirripedia: Rhizocephala)

DEFF Research Database (Denmark)

Lützen, Jørgen; Jespersen, Åse

1992-01-01

Interna development within the intertidal tropical crab, Leptodius exaratus, requires up to 4.5 months; the roots become distributed from the CNS along the major nerves and, when the crab moults, results in emergence of numerous externae located symmetrically on the abdomen and bases of the thora......Interna development within the intertidal tropical crab, Leptodius exaratus, requires up to 4.5 months; the roots become distributed from the CNS along the major nerves and, when the crab moults, results in emergence of numerous externae located symmetrically on the abdomen and bases...... of the thoracic appendages. As many externae drop off, their number is continuously reduced; the survivors reach sexual maturity and ovulate after 2.5 months and complete embryonic development after 2 more months. At the next moult a new and more numerous generation of externae appears, and this is repeated until...

On gonads and gadflies: the estrus angle.

Science.gov (United States)

Hillier, Stephen G

2017-06-01

The first sex steroid to be crystallized was the vertebrate ovarian hormone, estrone - a less potent metabolite of 17β-estradiol, which in mammals stimulates the female urge to mate (estrus). The gadfly (Greek oistros ) lent its name to the process of estrus, as an insect that bites and torments in classical Greek mythology. With the purification and crystallization of a moult-inducing steroid (ecdysone) from insects, an interesting parallel emerged between mating and moulting in lower mammals and arthropods. Ecdysterone (potent ecdysone metabolite) has anabolic effects in mammalian muscle cells that can be blocked by selective estrogen receptor antagonists. Insects utilize ecdysteroids in similar ways that vertebrates use estrogens, including stimulation of oocyte growth and maturation. Ecdysteroids also modify precopulatory insect mating behaviour, further reinforcing the gonad-gadfly/mate-moult analogy. © 2017 Society for Endocrinology.

Female reproductive cycle of the Southwestern Atlantic estuarine crab Chasmagnathus granulatus (Brachyura, Grapsoidea, Varunidae

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Romina B. Ituarte

2004-03-01

Full Text Available The female reproductive biology of a Chasmagnathus granulatus population inhabiting the area near the mouth of Mar Chiquita coastal lagoon, Argentina, was studied. An increase in air temperature during the spring is related to the start of the breeding period, when well defined egg-laying and hatching pulses were observed. Hatching is synchronic during the whole summer but the egg production was not, probably due to the gradual incorporation of young females to the reproductive population. Neither egg-laying nor larval release showed a clear relation to moon phase or tidal cycles, suggesting that reproduction is not rigidly programmed in this unpredictable habitat. Females moult at the beginning of autumn, after releasing the last larvae. However, a new cohort of ovocytes, which was in primary vitellogenesis before moulting, completed the secondary ovogenesis after moulting. Consequently, ovaries remained fully developed throughout the winter.

Moulting and moult quality in eye-stalk ablated penaeid prawn, Metapenaeus monoceros (Fabricius)

Digital Repository Service at National Institute of Oceanography (India)

Venkitaraman, P.R.; Sivadas, P.

stream_size 3 stream_content_type text/plain stream_name 4_Kerala_Sci_Cong_Proc_1992_271.pdf.txt stream_source_info 4_Kerala_Sci_Cong_Proc_1992_271.pdf.txt Content-Encoding ISO-8859-1 Content-Type text/plain; charset=ISO-8859-1 ...

Corticosterone mediated costs of reproduction link current to future breeding.

Science.gov (United States)

Crossin, Glenn T; Phillips, Richard A; Lattin, Christine R; Romero, L Michael; Williams, Tony D

2013-11-01

Life-history theory predicts that costs are associated with reproduction. One possible mediator of costs involves the secretion of glucocorticoid hormones, which in birds can be measured in feathers grown during the breeding period. Glucocorticoids mediate physiological responses to unpredictable environmental or other stressors, but they can also function as metabolic regulators during more predictable events such as reproduction. Here we show that corticosterone ("Cort") in feathers grown during the breeding season reflects reproductive effort in two Antarctic seabird species (giant petrels, Macronectes spp.). In females of both species, but not males, feather Cort ("fCort") was nearly 1.5-fold higher in successful than failed breeders (those that lost their eggs/chicks), suggesting a cost of successful reproduction, i.e., high fCort levels in females reflect the elevated plasma Cort levels required to support high metabolic demands of chick-rearing. Successful breeding also led to delayed moult prior to winter migration. The fCort levels and pre-migration moult score that we measured at the end of current breeding were predictive of subsequent reproductive effort in the following year. Birds with high fCort and a delayed initiation of moult were much more likely to defer breeding in the following year. Cort levels and the timing of moult thus provide a potential mechanism for the tradeoff between current and future reproduction. Crown Copyright © 2013. Published by Elsevier Inc. All rights reserved.

Experimental studies on the larval development of the shrimps Crangon crangon and C. allmanni

Science.gov (United States)

Criales, M. M.; Anger, K.

1986-09-01

Larvae of the shrimps Crangon crangon L. and C. allmanni Kinahan were reared in the laboratory from hatching through metamorphosis. Effects of rearing methods (larval density, application of streptomycin, food) and of salinity on larval development were tested only in C. crangon, influence of temperature was studied in both species. Best results were obtained when larvae were reared individually, with a mixture of Artemia sp. and the rotifer Brachionus plicatilis as food. Streptomycin had partly negative effects and was thus not adopted for standard rearing techniques. All factors tested in this study influenced not only the rates of larval survival and moulting, but also morphogenesis. In both species, in particular in C. crangon, a high degree of variability in larval morphology and in developmental pathways was observed. Unsuitable conditions, e.g. crowding in mass culture, application of antibiotics, unsuitable food (rotifers, phytoplankton), extreme temperatures and salinities, tend to increase the number of larval instars and of morphological forms. The frequency of moulting is controlled mainly by temperature. Regression equations describing the relations between the durations of larval instars and temperature are given for both Crangon species. The number of moults is a linear function of larval age and a power function of temperature. There is high variation in growth (measured as carapace length), moulting frequency, morphogenesis, and survival among hatches originating from different females. The interrelations between these different measures of larval development in shrimps and prawns are discussed.

Colour change in a structural ornament is related to individual quality, parasites and mating patterns in the blue tit

Science.gov (United States)

Badás, E. P.; Martínez, J.; Rivero-de Aguilar, J.; Ponce, C.; Stevens, M.; Merino, S.

2018-02-01

Carry-over effects refer to processes that occur in one season and influence fitness in the following. In birds, two costly activities, namely reproduction and moult, are restricted to a small time window, and sometimes overlap. Thus, colour in newly moulted feathers is likely to be affected by the costs of reproduction. Using models of bird vision we investigated male colour change in a free-living population of blue tits ( Cyanistes caeruleus) in three sampling occasions: spring 1, winter and spring 2. We related crown, tail, breast and cheek feather colouration after the moult (winter) to the intensity of infections by blood parasites during reproduction (spring 1). In the following spring (spring 2), we explored mating patterns with respect to changes in feather colour (springs 1 vs. 2). Males that were less intensely infected by the malaria parasite Plasmodium while breeding showed purer white cheek feathers in winter, which may indicate higher feather quality. Increased brightness in the white cheek was associated with better body condition during reproduction. In the following season, males with brighter cheeks paired with females that had noticeably brighter cheek patches compared to the male's previous mate. These results suggest that the conditions experienced during reproduction are likely to affect moult and thus feather colouration, at least in the white patch. High quality individuals may allocate resources efficiently during reproduction increasing future reproductive success through variation in mating patterns. Carry-over effects from reproduction might extend not only to the non-breeding phase, but also to the following breeding season.

A twelve-month field study of the West African Thrush Turdus pelios (Passeriformes: Muscicapidae: Part 2: annual cycles

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Akinsola I Akinpelu

2005-06-01

Full Text Available In Africa, birds inhabiting forested regions are less seasonal in their activities than those from open areas. In order to study annual cycles in forest regions of South western Nigeria, West African Thrushes (Turdus pelios were mist-netted and banded during the last two weeks of each month. The nest is a cup-shaped structure built out of grasses, herbs, weeds, roots and earth laid out in a clockwise manner. Only the nesting tree and feeding sites were defended during the breeding period. The clutch size was 2.69 ±0.20 eggs with a mean incubation period of 14.11 ±0.26 days. The mean nestling period was 15 ±1.00 days. The nestlings were fed on a variety of plant and animal matter, of which grass seeds and insects were predominant. Moult was found to be protracted with a population moult period of 194 days and a much shorter individual moult period. Moult and breeding periods were spread out: moult period dovetailed into the breeding period. The birds were found to gain weight during the period but they attained their maximum weight in August after the moult period. The lowest weight was recorded in February, during the peak of the dry season, when food availability was lower. Rev. Biol. Trop. 53(1-2:239-247. Epub 2005 Jun 24El nido del tordo africano occidental es una estructura en forma de copa construida con pastos, hierbas, malezas, raíces y tierra, proyectado en el sentido de las manecillas del reloj. Solamente el árbol con el nido y los sitios de alimentación son defendidos durante la crianza. El tamaño de la nidada fue 2.69 ± 0.20 huevos con un periodo de incubación de 14.11 ± 0.26 días. El periodo promedio de cría fue de 15 ± 1.00 días. Los polluelos fueron alimentados con una variedad de material animal y vegetal, predominando las semillas de pasto y los insectos. La muda del plumaje alar es prolongada, con un período poblacional de muda de 194 días y un periodo individual mucho menor. La muda y crianza son tan prolongados

Energetics of emergence in the cicadas, Cyclochila australasiae and Abricta curvicosta (Homoptera: Cicadidae).

Science.gov (United States)

Harvey, Prudence M; Thompson, Michael B

2006-09-01

The final moult in cicadas marks a major transition in lifestyle and is a behaviour that makes the cicada vulnerable to predation. Consequently, emergence times are short and, we predict, therefore the rate of energy consumption would be high. Hence, we measured the energetic cost of emergence in Cyclochila australasiae (green grocer) and Abricta curvicosta (floury baker) cicadas during the final moult from nymph to adult cicada. Maximum energy expended whilst emerging was compared between the sexes and species. Even though C. australasiae take longer to emerge than A. curvicosta, the mass-specific cost of emergence is not different between the two species (C. australasiae: 11.34+/-2.55 J g(-1); A. curvicosta: 12.91+/-1.90 J g(-1)). The mass-specific metabolic rates of fully emerged adults of both species are approximately twice those of the nymphs and the maximum metabolic rate during emergence is about 1.5 times higher than the resting metabolic rate of emerged adults. Emergence times, as indicated by rates of oxygen consumption, are longer than expected and probably reflect limitations in the oxygen capacity of the cicadas during moulting.

Growth and reproduction investment of the young of the year of the squat lobster Munida gregaria (Crustacea: Anomura in the Patagonian coast

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Martin Varisco

2015-09-01

Full Text Available The growth and reproduction investment of the young of the year (0+ of the squat lobster Munida gregaria in San Jorge Gulf, Argentina, were analysed. Moult cycle and size frequency distribution were studied in monthly field samples. Experiments to determine moult increments and intermoult duration were conducted. Sexual maturity, fecundity and reproductive output were analysed in field samples. In addition, maturity experiments in laboratory cultures were conducted. After settlement (November, juveniles showed fast growth until winter (July and growth restarted in September-October. At the beginning of the mating period (early June, males 0+ exhibited mature gonads, whereas females 0+ only showed previtellogenic oocytes. Experimental data showed that females with developed gonads had smaller-size increments in the previous moult. Fecundity and reproductive output were significantly lower in females 0+ than in older females. The early life history of M. gregaria in San Jorge Gulf differs from that of southern populations as those of Beagle Channel and Strait of Magellan due to faster growth and early reproductive investment. Our results suggest that females 0+ of M. gregaria have two investment strategies: early maturity with low fecundity and delayed maturity with higher future fecundity.

Biochemical and locomotor responses of Carcinus maenas exposed to the serotonin reuptake inhibitor fluoxetine.

Science.gov (United States)

Mesquita, Sofia Raquel; Guilhermino, Lúcia; Guimarães, Laura

2011-10-01

The aim of this study was to assess the effects of the widely used anti-depressant fluoxetine on behaviour (locomotion), moulting, neuromuscular transmission, energy production and anti-oxidant defences' efficiency of the epibenthic crab Carcinus maenas. Crabs were individually exposed to fluoxetine concentrations for 7d. Effects on locomotion were assessed at the end of the exposure using an open field test adapted to C. maenas in the present study. Tissue samples were later collected to evaluate fluoxetine effects on physiological functions using the activity of key enzymes and other parameters as biomarkers, namely: N-acetyl-β-glucosaminidase (NAGase) in the epidermis (moulting) and the hepatopancreas; cholinesterases (ChE) in muscle (neuromuscular cholinergic transmission); NADP(+)-dependent isocitrate dehydrogenase (IDH) and lactate dehydrogenease (LDH) in muscle (energy production); glutathione S-transferases (GST) in hepatopancreas (biotransformation and oxidative stress system); glutathione reductase (GR), and glutathione peroxidade (GPx), total glutathione levels (TG) and lipid peroxidation levels in the hepatopancreas (anti-oxidant defences and oxidative damage). Because no information on C. maenas NAGase activity was previously available, its variation during the moult cycle was also investigated. The results showed that locomotion was significantly increased at fluoxetine concentrations equal or above 120 μg L⁻¹, with animals spending more time moving, walking longer distances than controls. Levels of NAGase activity were found to vary in relation to C. maenas moult cycle, but no alterations were observed after exposure to fluoxetine. Significant increases in the activity of ChE, GST and GR enzymes, and the levels of TG were found, with a lowest observed effect concentration (LOEC) of 120 μg L⁻¹. Effects on locomotion were significantly and positively correlated to those induced on ChE activity. The results raise concern when hypothesising

Moult-inhibiting fusion protein augments while polyclonal antisera attenuate moult stages and duration in Penaeus monodon

Digital Repository Service at National Institute of Oceanography (India)

Vrinda, S.; Jasmin, C.; Sivakumar, K.C.; Jose, B.; Philip, R; BrightSingh, I

thioredoxin-fused mature MIH I protein (mf-PmMIH I) of P. monodon in a bacterial system and its use as antigen to raise polyclonal antiserum (anti-mf-PmMIH I). The mature MIH I gene of 231 bp, that codes for 77 amino acids, was cloned into the Escherichia coli...

Status of harbour seals (Phoca vitulina in mainland Norway

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Kjell Tormod Nilssen

2010-09-01

Full Text Available Harbour seals were counted along the entire Norwegian coast at known moulting haulout sites in the period mid-August to early September 2003-2006. In 2003-2005, almost all known moulting areas from Finnmark to Vestfold counties were covered by aerial photo surveys flown at altitudes of approximately 800-900 ft (243-274m, and at low tide (± 2 hours. Surveys in the Østfold County were flown in 2003-2006 at 300 ft (91m, and the small tidal amplitudes permitted counts to be carried out irrespective of the tidal cycle. In some sub-areas, two or three independent surveys were conducted. Visual counts using binoculars from smaller boats and islands were carried out in some selected areas. The surveys revealed a total minimum population of 6,705 harbour seals in Norwegian waters. Harbour seals were most abundant in the Nordland and Sør-Trøndelag counties with minimum estimates of approximately 2,500 and 1,500 seals, respectively. The presented minimum estimate is approximately 800 seals lower than an estimate obtained in a comparable study carried out during the moult in 1996-1999. Increased anthropogenic removals, and the phocine distemper virus (PDV epidemic in the Skagerrak region in 2002, may have contributed to the current lower estimate.

Trace element analysis in the serum and hair of Antarctic leopard seal, Hydrurga leptonyx, and Weddell seal, Leptonychotes weddellii

Energy Technology Data Exchange (ETDEWEB)

Gray, Rachael [Faculty of Veterinary Science, University of Sydney, NSW 2006 Australia (Australia); Australian Marine Mammal Research Centre PO Box 20 Mosman, NSW 2088 (Australia)], E-mail: rgray@vetsci.usyd.edu.au; Canfield, Paul [Faculty of Veterinary Science, University of Sydney, NSW 2006 (Australia); Rogers, Tracey [Australian Marine Mammal Research Centre PO Box 20 Mosman, NSW 2088 (Australia); Evolution and Ecology Research Centre and School of Biological Earth and Environmental Sciences, University of New South Wales, NSW 2052 (Australia)

2008-07-25

Leopard seal, Hydrurga leptonyx, and Weddell seal, Leptonychotes weddellii, occupy an upper trophic level within the Antarctic ecosystem and are useful indicator species in the Southern Ocean of trace element concentrations. Reference values for the concentration of 19 trace elements were determined in the serum and hair of leopard and Weddell seals sampled in Eastern Antarctica. These reference values can be used as 'baseline' levels for monitoring trace element concentrations in these species. Greater trace element concentrations were determined in hair compared to serum, indicating different time scales of trace element accumulation in these samples. For the majority of trace elements, except for Se in the leopard seal samples and Cr in the Weddell seal samples, significant regression relationships for trace element concentrations in hair and serum were not elucidated. Significant differences were determined in the concentrations of seven out of 15 elements with hair type, moult and new, in the leopard seal; concentrations in moult hair were determined to be greater than in new hair for all elements except Zn. Hair analysis was determined to be useful for monitoring exposure to trace elements and when collected off the ice from moulting seals, hair can be employed as a non-invasive sample for trace element analysis in leopard and Weddell seals.

Experimental Studies on Plutonium Kinetics in Marine Biota

International Nuclear Information System (INIS)

Fowler, S.; Heyraud, M.; Beasley, T.M.

1976-01-01

Laboratory experiments were undertaken to measure plutonium flux through marine organisms and to clarify the pathways by which this important element is cycled in the marine environment. The use of a specially prepared isotope, plutonium-237, allowed measurements to be made with standard Nal(Tl) scintillation techniques. Mussels, shrimp and worms were allowed to accumulate plutonium-237 from sea water for up to 25 days. Accumulation by shrimp was relatively slow and the degree of uptake was strongly influenced by moulting. Cast moults contained large fractions of the shrimps ' plutonium content, indicating the high affinity of plutonium for surface areas. Only small amounts of the isotope in the moult are lost to water; hence, moulting is considered to be an important biological parameter in the biogeochemical cycling of plutonium. Mussels attained higher concentration factors than shrimp with most of the accumulated isotope (> 80%) located in the shell. Byssus threads often contained large fractions of the mussels' plutonium-237 content and reached concentration factors as high as 4100. Worms readily accumulated plutonium-237 in either the +4 or +6 state, reaching concentration factors of approximately 200, Retention studies indicated a relatively slow loss of plutonium-237 from all animals studied. In the case of mussels, a computed half-time for a large fraction of the animals plutonium content was of the order of 2 years. The more rapid loss from shrimp (Tb 1/2 = 1.5 months) was due principally to the large fraction of plutonium lost at moult. Food chain studies with shrimp indicated that tissue build-up via plutonium ingestion would be a slow process. Total excretion was not entirely a result of passing contaminated food through the gut; approximately 15% of the ingested plutonium was removed from the contaminated food and subsequently excreted by processes other than defaecation of labelled food. Ratios of four different plutonium isotopes used in

Experimental studies on plutonium kinetics in marine biota

International Nuclear Information System (INIS)

Fowler, S.; Heyraud, M.; Beasley, T.M.

1975-01-01

Laboratory experiments were undertaken to measure plutonium flux through marine organisms and to clarify the pathways by which this important element is cycled in the marine environment. The use of a specially prepared isotope, plutonium-237, allowed measurements to be made with standard NaI(Tl) scintillation techniques. Mussels, shrimp and worms were allowed to accumulate plutonium-237 from seawater for up to 25 days. Accumulation by shrimp was relatively slow and the degree of uptake was strongly influenced by moulting. Cast moults contained large fractions of the shrimps' plutonium content, indicating the high affinity of plutonium for surface areas. Only small amounts of the isotope in the moult are lost to water; hence, moulting is considered to be an important biological parameter in the biogeochemical cycling of plutonium. Mussels attained higher concentration factors than shrimp with most of the accumulated isotope (>80%) located in the shell. Byssus threads often contained large fractions of the mussels' plutonium-237 content and reached concentration factors as high as 4100. Worms readily accumulated plutonium-237 in either the +4 or +6 state, reaching concentration factors of approximately 200. Retention studies indicated a relatively slow loss of plutonium-237 from all animals studied. In the case of mussels, a computed half-time for a large fraction of the animals' plutonium content was of the order of 2 years. The more rapid loss from shrimp (Tbsub(1/2)=1.5 months) was due principally to the large fraction of plutonium lost at moult. Food chain studies with shrimp indicated that tissue build-up via plutonium ingestion would be a slow process. Total excretion was not entirely a result of passing contaminated food through the gut; approximately 15% of the ingested plutonium was removed from the contaminated food and subsequently excreted by processes other than defaecation of labelled food. Ratios of four different plutonium isotopes used in the

N-acetyl-β-D-glucosaminidase activity in feral Carcinus maenas exposed to cadmium

International Nuclear Information System (INIS)

Mesquita, Sofia Raquel; Ergen, Şeyda Fikirdeşici; Rodrigues, Aurélie Pinto; Oliva-Teles, M. Teresa; Delerue-Matos, Cristina; Guimarães, Laura

2015-01-01

Highlights: • Effects of Cd on NAGase activity of crabs from low impacted and polluted sites. • Inhibition of epidermal NAGase by Cd in crabs from both sites. • Inhibition of NAGase in digestive gland only in crabs from low impacted site. • Glutathione role in enhanced tolerance to Cd of crabs from polluted site. - Abstract: Cadmium is a priority hazardous substance, persistent in the aquatic environment, with the capacity to interfere with crustacean moulting. Moulting is a vital process dictating crustacean growth, reproduction and metamorphosis. However, for many organisms, moult disruption is difficult to evaluate in the short term, what limits its inclusion in monitoring programmes. N-acetyl-β-D-glucosaminidase (NAGase) is an enzyme acting in the final steps of the endocrine-regulated moulting cascade, allowing for the cast off of the old exoskeleton, with potential interest as a biomarker of moult disruption. This study investigated responses to waterborne cadmium of NAGase activity of Carcinus maenas originating from estuaries with different histories of anthropogenic contamination: a low impacted and a moderately polluted one. Crabs from both sites were individually exposed for seven days to cadmium concentrations ranging from 1.3 to 2000 μg/L. At the end of the assays, NAGase activity was assessed in the epidermis and digestive gland. Detoxification, antioxidant, energy production, and oxidative stress biomarkers implicated in cadmium metabolism and tolerance were also assessed to better understand differential NAGase responses: activity of glutathione S-transferases (GST), glutathione peroxidase (GPx) glutathione reductase (GR), levels of total glutathiones (TG), lipid peroxidation (LPO), lactate dehydrogenase (LDH), and NADP + -dependent isocitrate dehydrogenase (IDH). Animals from the moderately polluted estuary had lower NAGase activity both in the epidermis and digestive gland than in the low impacted site. NAGase activity in the epidermis

N-acetyl-β-D-glucosaminidase activity in feral Carcinus maenas exposed to cadmium

Energy Technology Data Exchange (ETDEWEB)

Mesquita, Sofia Raquel, E-mail: smesquita@ciimar.up.pt [Interdisciplinary Centre of Marine and Environmental Research (CIIMAR/CIMAR), University of Porto, Rua dos Bragas 289, P 4050-123 Porto (Portugal); ICBAS – Institute of Biomedical Sciences Abel Salazar, University of Porto, Rua Jorge Viterbo Ferreira 228, 4050-313 Porto (Portugal); Ergen, Şeyda Fikirdeşici [Faculty of Science, Ankara University, Department of Biology, 06100 Tandogan, Ankara (Turkey); Rodrigues, Aurélie Pinto [Interdisciplinary Centre of Marine and Environmental Research (CIIMAR/CIMAR), University of Porto, Rua dos Bragas 289, P 4050-123 Porto (Portugal); ICBAS – Institute of Biomedical Sciences Abel Salazar, University of Porto, Rua Jorge Viterbo Ferreira 228, 4050-313 Porto (Portugal); Oliva-Teles, M. Teresa; Delerue-Matos, Cristina [REQUIMTE, School of Engineering, Polytechnic Institute of Porto, Rua Dr. António Bernardino de Almeida 431, 4200-072 Porto (Portugal); Guimarães, Laura, E-mail: lguimaraes@ciimar.up.pt [Interdisciplinary Centre of Marine and Environmental Research (CIIMAR/CIMAR), University of Porto, Rua dos Bragas 289, P 4050-123 Porto (Portugal)

2015-02-15

Highlights: • Effects of Cd on NAGase activity of crabs from low impacted and polluted sites. • Inhibition of epidermal NAGase by Cd in crabs from both sites. • Inhibition of NAGase in digestive gland only in crabs from low impacted site. • Glutathione role in enhanced tolerance to Cd of crabs from polluted site. - Abstract: Cadmium is a priority hazardous substance, persistent in the aquatic environment, with the capacity to interfere with crustacean moulting. Moulting is a vital process dictating crustacean growth, reproduction and metamorphosis. However, for many organisms, moult disruption is difficult to evaluate in the short term, what limits its inclusion in monitoring programmes. N-acetyl-β-D-glucosaminidase (NAGase) is an enzyme acting in the final steps of the endocrine-regulated moulting cascade, allowing for the cast off of the old exoskeleton, with potential interest as a biomarker of moult disruption. This study investigated responses to waterborne cadmium of NAGase activity of Carcinus maenas originating from estuaries with different histories of anthropogenic contamination: a low impacted and a moderately polluted one. Crabs from both sites were individually exposed for seven days to cadmium concentrations ranging from 1.3 to 2000 μg/L. At the end of the assays, NAGase activity was assessed in the epidermis and digestive gland. Detoxification, antioxidant, energy production, and oxidative stress biomarkers implicated in cadmium metabolism and tolerance were also assessed to better understand differential NAGase responses: activity of glutathione S-transferases (GST), glutathione peroxidase (GPx) glutathione reductase (GR), levels of total glutathiones (TG), lipid peroxidation (LPO), lactate dehydrogenase (LDH), and NADP{sup +}-dependent isocitrate dehydrogenase (IDH). Animals from the moderately polluted estuary had lower NAGase activity both in the epidermis and digestive gland than in the low impacted site. NAGase activity in the

Effects of the essential oil obtained from Pilocarpus spicatus Saint-Hilaire (Rutaceae on the development of Rhodnius prolixus nymphae

Directory of Open Access Journals (Sweden)

Cícero B. Mello

Full Text Available Bioassays against fifth-instar nymphae of Rhodnius prolixus were conducted with essential oil of Pilocarpus spicatus extracted by hydrodistillation. The main results may be summarized as follows: (i high levels of toxicity and paralysis together with discrete moulting inhibition were caused by topical application of either 0.5 µL or 1.0 µL per insect of the crude essential oil; (ii partial fagoinhibition, high moulting inhibition, prolonged intermoulting period and high number of paralyzed insects, but no toxicity were observed after oral treatment using either 5 µL or 10 µL of Pilocarpus spilcatus essential oil per mL of ingested blood meal. The importance of these results in relation to the relevant biological events in R. prolixus is herein discussed.

Experimental studies on the cannibalistic habit of Macrobrachium rosenbergii (de Man)

Digital Repository Service at National Institute of Oceanography (India)

Nair, K.K.C.; Branislav, M.; Rosenthal, H.; Jayalakshmy, K.V.; Nost, J.

found more susceptible to cannibalism soon after the moult. This can be guarded by providing suitable hideouts. Dried commercial feed, alternated with fresh animal tissues was found to reduce cannibalism upt 70%....

The impact of the 1993 Braer oil spill on grey seals in Shetland

International Nuclear Information System (INIS)

Hall, AilsaJ.; Watkins, John; Hiby, Lex

1996-01-01

Signs of acute respiratory distress were reported in moulting grey seals (Halichoerus grypus) hauled out on Lady's Holm, Shetland, following the Braer oil spill in January, 1993. Behavioural observations carried out between 16 January and 13 February 1993 showed that the proportion of animals exhibiting a discharge of nasal mucus was significantly higher than the proportion at a control site in the north (Papa Stour). The proportion of animals affected on Lady's Holm increased for up to one month following the spill. However, the time lag between exposure and peak response was approximately 30 days, longer than may be expected for an acute effect. The proportion of non-specific signs of respiratory distress in unexposed Shetland seals was assessed from observations made between 16 January and 25 January 1994. Symptoms similar to those seen in 1993 were also reported during this period, but the proportion of affected animals was higher in 1993. Symptoms were not observed at a grey seal moult site on the east coast of England in March 1993 and 1994. Grey seals moulting in Shetland during the time of the oil spill may have been acutely affected by exposure to hydrocarbons, but without sufficient baseline data on the occurrence of respiratory distress in grey seals it is difficult to determine the proportion attributable to other causes

Study of sunless tanning formulas using molted snake skin as an alternative membrane model.

Science.gov (United States)

Balogh, T S; Pedriali, C A; Gama, R M; de Oliveira Pinto, C A S; Bedin, V; Villa, R T; Kaneko, T M; Consiglieri, V O; Velasco, M V R; Baby, A R

2011-08-01

Sunless tanning formulas have become increasingly popular in recent years for their ability to give people convincing tans without the dangers of skin cancer. Most sunless tanners currently on the market contain dihydroxyacetone (DHA), a keto sugar with three carbons. The temporary pigment provided by these formulas is designed to resemble a UV-induced tan. This study evaluated the effectiveness of carbomer gels and cold process self emulsifying bases on skin pigmentation, using different concentrations of a chemical system composed of DHA and N-acetyl tyrosine, which are found in moulted snake skins and their effectiveness was tested by Mexameter(®) MX 18. Eight different sunless tanning formulas were developed, four of which were gels and four of which were emulsions (base, base plus 4.0%, 5.0% and 6.0% (w/w) of a system of DHA and N-acetyl tyrosine). Tests to determine the extent of artificial tanning were done by applying 30 mg cm(-2) of each formula onto standard sizes of moulted snake skin (2.0 cm × 3.0 cm). A Mexameter(®) MX 18 was used to evaluate the extent of coloration in the moulted snake skin at T(0) (before the application) and after 24, 48, 72, 168, 192 and 216 h. The moulted snake skins can be used as an alternative membrane model for in vitro sunless tanning efficacy tests due to their similarity to the human stratum corneum. The DHA concentration was found to influence the initiation of the pigmentation in both sunless tanning systems (emulsion and gel) as well as the time required to increases by a given amount on the tanning index. In the emulsion system, the DHA concentration also influenced the final value on the tanning index. The type of system (emulsion or gel) has no influence on the final value in the tanning index after 216 h for samples with the same DHA concentration. © 2011 The Authors. ICS © 2011 Society of Cosmetic Scientists and the Société Française de Cosmétologie.

Using growth measures in the freshwater shrimp Caridina nilotica as biomarkers of Roundup® pollution of South African freshwater systems

Science.gov (United States)

Mensah, P. K.; Muller, W. J.; Palmer, C. G.

There has been global concern about the effect of toxic chemicals on aquatic biota due to the upsurge in contamination of aquatic ecosystems by these chemicals, which includes pesticides. Roundup® and other glyphosate-based herbicides are frequently used in the chemical control of weeds and invading alien plant species in South Africa. These bio-active chemicals ultimately get into water courses directly or indirectly through processes such as drifting, leaching, surface runoff and foliar spray of aquatic nuisance plants. However, there is no South African water quality guideline to protect indigenous freshwater non-target organisms from the toxic effects of glyphosate-based herbicides. This study evaluated the possible use of growth measures in Caridina nilotica as biomarkers of Roundup® pollution as part of developing glyphosate water quality guideline for the protection of aquatic life in South Africa. Using static-renewal methods in a 25-day growth toxicity test, 40 days post hatch shrimps were exposed to different sub-lethal Roundup® concentrations of 0.0 (control), 2.2, 2.8, 3.4, 4.3 and 5.4 mg/L. Shrimps were fed daily with TetraMin® flake food and test solutions changed every third day. Shrimp total lengths and wet weights were measured every fifth day. These data were used to determine the shrimp’s growth performance and feed utilization in terms of percent weight gain (PWG), percent length gain (PLG), specific growth rate (SGR), condition factor (CF), feed intake (FI), feed conversion ratio (FCR) and feed conversion efficiency (FCE). Moulting was observed for 14 days and the data used to determine the daily moult rate for each concentration. Results of growth performance and food utilization indices showed that growth was significantly impaired in all exposed groups compared to control (p < 0.05). Moulting frequency was also higher in all exposed groups than in control (p < 0.05). Although all the tested growth measures proved to be possible

Ostrich: Journal of African Ornithology - Vol 76, No 3 (2005)

African Journals Online (AJOL)

Demography of the Seychelles Black Paradise-flycatcher: considerations for ... to the Brown-necked Parrot P. fuscicollis fuscicollis and the Grey-headed Parrot P. f. ... Chestnut Weaver Ploceus rubiginosus biometrics and primary moult in ...

Isolation of crustecdysone (20R-hydroxyecdysone) from a crayfish (Jasus lalandei H. Milne-Edwards)

Science.gov (United States)

Horn, D. H. S.; Fabbri, S.; Hampshire, F.; Lowe, M. E.

1968-01-01

1. A small amount (2mg.) of crustecdysone, a moulting hormone of crustaceans, was isolated from 1 ton of crayfish waste. 2. The purification procedure used was developed with the aid of crustacean and insect bioassays. 3. CM-Sephadex was found to be superior to Sephadex and very effective for the chromatographic separation of crustecdysone from other non-ionic compounds. The higher efficiency of CM-Sephadex is attributed to the greater number of carboxyl groups available for hydrogen-bonding. 4. Reversed-phase chromatography, with butan-1-ol–cyclohexane mixtures as the stationary phase and water as the flowing phase, proved superior to countercurrent distribution with these solvents for the fractionation of purified extracts. 5. A second moulting hormone, deoxycrustecdysone, and the red-concentrating hormone were obtained in a partially purified form. PMID:5685865

Mitosis in storage cells of the eutardigrade Richtersius coronifer

Czech Academy of Sciences Publication Activity Database

Czerneková, Michaela; Jönsson, K. I.

2016-01-01

Roč. 178, č. 4 (2016), s. 888-896 ISSN 0024-4082 Institutional support: RVO:67985823 Keywords : cell division * coelomocytes * development * mitotic index * moulting * tardigrada Subject RIV: ED - Physiology Impact factor: 2.711, year: 2016

Growth of juvenile shrimp Metapenaeus monoceros fed with squid and mussel

Digital Repository Service at National Institute of Oceanography (India)

Achuthankutty, C.T.; Nair, S.R.S.; Krishnakumari, L.

Small juveniles of both sexes and females of large juveniles of Metapenaeus monoceros attained faster growth with squid diet. Males of large juveniles registered better growth with mussel diet. No significant difference was observed in moult weights...

Ecdysteroid receptor docking suggests that dibenzoylhydrazine-based insecticides are devoid of any deleterious effect on the parasitic wasp Psyttalia concolor (Hym. Braconidae).

Science.gov (United States)

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

2012-07-01

The moulting accelerating compounds (MACs) or ecdysteroid agonists represent a selective group of insecticides acting upon binding to the ecdysteroid receptor (EcR) and leading to lethal premature moulting in larval stages and aborted reproduction in adults. Psyttalia concolor Szèpl. is a useful parasitic wasp attacking important tephritid pests such as the medfly and olive fruit fly. Contact and oral exposure in the laboratory of female parasitic wasps to the dibenzoylhydrazine-based methoxyfenozide, tebufenozide and RH-5849 did not provoke negative effects. No mortality and no reduction in beneficial capacity were observed. The ligand-binding domain (LBD) of the EcR of P. concolor was sequenced, and a homology protein model was constructed which confirmed a cavity structure with 12 α-helices, harbouring the natural insect moulting hormone 20-hydroxyecdysone. However, a steric clash occurred for the MAC insecticides owing to a restricted extent of the ligand-binding cavity of the PcLBD-EcR, while they did dock well in that of susceptible insects. The insect toxicity assays demonstrated that MACs are selective for P. concolor. The modelling/docking experiments are indications that these insecticides do not bind with the LBD-EcR of P. concolor and support the theory that they show no biological effects in the parasitic wasp. These data may help in explaining the compatible use of MACs together with parasitic wasps in IPM programmes. Copyright © 2012 Society of Chemical Industry.

Factors influencing long-term and seasonal waterbird abundance ...

African Journals Online (AJOL)

... influence waterbird communities include rainfall quantity and distribution, waterbird movement, breeding and moulting; anthropogenic drivers include activities such as fishing and agriculture. Results suggest that seasonal variations in resource availability influenced the waterbird community composition and abundance, ...

Preliminary In Vivo Experiments on Adhesion of Geckos

OpenAIRE

Lepore, E.; Brianza, S.; Antoniolli, F.; Buono, M.; Carpinteri, A.; Pugno, N.

2008-01-01

We performed preliminary experiments on the adhesion of a Tokay gecko on surfaces with different roughness, with or without particles with significant different granulometry, before/after or during the moult. The results were analyzed using the Weibull statistics.

The ultrastructural basis of steroid production in the Y-organ and the mandibular organ of the crabs Hemigrapsus nudus (Dana) and Carcinus maenas L.

Science.gov (United States)

Buchholz, C; Adelung, D

1980-01-01

The ultrastructure of the steroid producing Y-organ and the mandibular organ of the crustaceans Hemigrapsus nudus and Carcinus maenas has been studied with reference to the well investigated steroid secreting cells (SSC) of mammals. In accordance with the most important characteristic of mammalian SSC, abundant SER could be shown in the Y-organ, where it is unevenly distributed. The amount of SER seems to vary in correlation with the secretion of moulting hormone during the moult cycle. Most Y-organ cells contain a great number of mitochondria of the tubular type, another important characteristic of mammalian SSC. The ultrastructure of the mandibular organ of C. maenas differs considerably from that of the Y-organ. Some SER was found, mitochondria of unusual shape and size were conspicuous. No definite conclusion as to the function of the mandibular organ is yet to be drawn.

Ostrich: Journal of African Ornithology - Vol 78, No 3 (2007)

African Journals Online (AJOL)

Moult patterns in the Long-tailed Hawk Urotriorchis macrourus · EMAIL FULL TEXT EMAIL FULL TEXT DOWNLOAD FULL TEXT DOWNLOAD FULL TEXT. Michel Louette, 577-582. http://dx.doi.org/10.2989/OSTRICH.2007.78.3.4.315 ...

Conservation of lepidopteran ecdysteroid receptor provides evidence for butterfly susceptibility to diacylhydrazine and bisacylhydrazine chemicals

Science.gov (United States)

Diacylhydrazine (DAH) and bisacylhydrazine (BAH) chemicals (e.g., methoxyfenozide and tebufenozide, respectively), also known as moulting accelerating compounds, act as agonists of the ecdysteroid receptor (EcR), and have been used as selective insecticides for pests within the o...

Concept to practice: A hazard-based pharmaceutical prioritization framework

Science.gov (United States)

Diacylhydrazine (DAH) and bisacylhydrazine (BAH) chemicals (e.g., methoxyfenozide and tebufenozide, respectively), also known as moulting accelerating compounds, act as agonists of the ecdysteroid receptor (EcR), and have been used as selective insecticides for pests within the o...

BACULOVIRUS REPLICATION ALTERS HORMONE-REGULATED HOST DEVELOPMENT.

Science.gov (United States)

The baculovirus Lymantria dispar nuclear polyhedrosis virus interferes with insect larval development by altering the host's hormonal system. The level of haemolymph ecdysteroids, the insect moulting hormone, was found to be higher in virus-infected larvae than in uninfected cont...

Preliminary In Vivo Experiments on Adhesion of Geckos

Directory of Open Access Journals (Sweden)

E. Lepore

2008-01-01

Full Text Available We performed preliminary experiments on the adhesion of a Tokay gecko on surfaces with different roughness, with or without particles with significant different granulometry, before/after or during the moult. The results were analyzed using the Weibull statistics.

Twisted Winged Endoparasitoids

Indian Academy of Sciences (India)

females are typically maggot-like and neotenic, living within the body of the host .... viviparously and emerges through the genital opening of the female. ... itself with the host tissue for evading the hosts' immune system. The next moult leads to ...

Fault bars in bird feathers: mechanisms, and ecological and evolutionary causes and consequences.

Science.gov (United States)

Jovani, Roger; Rohwer, Sievert

2017-05-01

Fault bars are narrow malformations in feathers oriented almost perpendicular to the rachis where the feather vein and even the rachis may break. Breaks in the barbs and barbules result in small pieces of the feather vein being lost, while breaks in the rachis result in loss of the distal portion of the feather. Here, we provide a comprehensive review of 74 papers on fault bar formation in hopes of providing a clearer approach to their study. First, we review the evidence that the propensity to develop fault bars is modified by natural selection. Given that fault bars persist in the face of survival costs, we conclude that they must be an unfortunate consequence of some alternative adaptation that outweighs the fitness costs of fault bars. Second, we summarize evidence that the development of fault bars is triggered by psychological stress such as that of handling or predation attempts, and that they persist because the sudden contractions of the muscles in the feather follicle that control fright moults also causes the development of fault bars in growing feathers. Third, we review external and physiological (e.g. corticosterone) agents that may affect the likelihood that an acute stress will result in a growing feather exhibiting a fault bar. These modifying factors have often been treated as fundamental causes in the earlier literature on fault bars. Fourth, we then use this classification to propose a tentative model where fault bars of different severity (from light to severe) are the outcome of the interaction between the propensity to produce fault bars (which differs between species, individuals and feather follicles within individuals) and the intensity of the perturbation. This model helps to explain contradictory results in the literature, to identify gaps in our knowledge, and to suggest further studies. Lastly, we discuss ways in which better understanding of fault bars can inform us about other aspects of avian evolutionary ecology, such as the

Use of agricultural fields by ruffs staging in southwest Friesland in 2003–2013

NARCIS (Netherlands)

Schmaltz, Lucie E.; Vega, Marta L.; Verkuil, Yvonne I.; Hooijmeijer, Joslyn; Piersma, Theunis

2016-01-01

Intensive dairy farming has changed the agricultural grassland areas of The Netherlands profoundly, with negative impacts on the reproduction of the shorebirds breeding there. This modern agricultural landscape also forms a staging site for migrating shorebirds, where they moult and replenish fuel

No evidence for general condition-dependence of structural plumage colour in blue tits: an experiment

NARCIS (Netherlands)

Peters, A.; Kurvers, R.H.J.M.; Roberts, M.L.; Delhey, K.

2011-01-01

Condition-dependence is a central but contentious tenet of evolutionary theories on the maintenance of ornamental traits, and this is particularly true for structural plumage colour. By providing diets of different nutritional quality to moulting male and female blue tits, we experimentally

Effect of exposing pupae of flesh fly Parasarcophaga ruficornis F. to superficial X-rays

International Nuclear Information System (INIS)

Kumar, K.; Srivastava, U.S.

1991-01-01

Irradiation of pupae of Parasarcophaga ruficornis with different doses of superficial X-rays leads to lethality and interference with moulting and metamorphosis. Younger pupae are more radiosensitive in respect of lethality and metamorphosis to older ones. (author). 12 ref., 9 figs., 1 tab

The Little Penguin (Eudyptula minor) as an indicator of coastal trace metal pollution.

Science.gov (United States)

Finger, Annett; Lavers, Jennifer L; Dann, Peter; Nugegoda, Dayanthi; Orbell, John D; Robertson, Bruce; Scarpaci, Carol

2015-10-01

Monitoring trace metal and metalloid concentrations in marine animals is important for their conservation and could also reliably reflect pollution levels in their marine ecosystems. Concentrations vary across tissue types, with implications for reliable monitoring. We sampled blood and moulted feathers of the Little Penguin (Eudyptula minor) from three distinct colonies, which are subject to varying levels of anthropogenic impact. Non-essential trace metal and metalloid concentrations in Little Penguins were clearly linked to the level of industrialisation adjacent to the respective foraging zones. This trend was more distinct in blood than in moulted feathers, although we found a clear correlation between blood and feathers for mercury, lead and iron. This study represents the first reported examination of trace metals and metalloids in the blood of any penguin species and demonstrates that this high trophic feeder is an effective bioindicator of coastal pollution. Copyright © 2015 Elsevier Ltd. All rights reserved.

Interpopulation Variation in Contour Feather Structure Is Environmentally Determined in Great Tits

Science.gov (United States)

Broggi, Juli; Gamero, Anna; Hohtola, Esa; Orell, Markku; Nilsson, Jan-Åke

2011-01-01

Background The plumage of birds is important for flying, insulation and social communication. Contour feathers cover most of the avian body and among other functions they provide a critical insulation layer against heat loss. Feather structure and composition are known to vary among individuals, which in turn determines variation in the insulation properties of the feather. However, the extent and the proximate mechanisms underlying this variation remain unexplored. Methodology/Principal Findings We analyzed contour feather structure from two different great tit populations adapted to different winter regimes, one northern population in Oulu (Finland) and one southern population in Lund (Sweden). Great tits from the two populations differed significantly in feather structure. Birds from the northern population had a denser plumage but consisting of shorter feathers with a smaller proportion containing plumulaceous barbs, compared with conspecifics from the southern population. However, differences disappeared when birds originating from the two populations were raised and moulted in identical conditions in a common-garden experiment located in Oulu, under ad libitum nutritional conditions. All birds raised in the aviaries, including adult foster parents moulting in the same captive conditions, developed a similar feather structure. These feathers were different from that of wild birds in Oulu but similar to wild birds in Lund, the latter moulting in more benign conditions than those of Oulu. Conclusions/Significance Wild populations exposed to different conditions develop contour feather differences either due to plastic responses or constraints. Environmental conditions, such as nutrient availability during feather growth play a crucial role in determining such differences in plumage structure among populations. PMID:21949798

Interpopulation variation in contour feather structure is environmentally determined in great tits.

Directory of Open Access Journals (Sweden)

Juli Broggi

Full Text Available The plumage of birds is important for flying, insulation and social communication. Contour feathers cover most of the avian body and among other functions they provide a critical insulation layer against heat loss. Feather structure and composition are known to vary among individuals, which in turn determines variation in the insulation properties of the feather. However, the extent and the proximate mechanisms underlying this variation remain unexplored.We analyzed contour feather structure from two different great tit populations adapted to different winter regimes, one northern population in Oulu (Finland and one southern population in Lund (Sweden. Great tits from the two populations differed significantly in feather structure. Birds from the northern population had a denser plumage but consisting of shorter feathers with a smaller proportion containing plumulaceous barbs, compared with conspecifics from the southern population. However, differences disappeared when birds originating from the two populations were raised and moulted in identical conditions in a common-garden experiment located in Oulu, under ad libitum nutritional conditions. All birds raised in the aviaries, including adult foster parents moulting in the same captive conditions, developed a similar feather structure. These feathers were different from that of wild birds in Oulu but similar to wild birds in Lund, the latter moulting in more benign conditions than those of Oulu.Wild populations exposed to different conditions develop contour feather differences either due to plastic responses or constraints. Environmental conditions, such as nutrient availability during feather growth play a crucial role in determining such differences in plumage structure among populations.

Use of secondary structural information and Cα-Cα distance ...

Indian Academy of Sciences (India)

PRAKASH KUMAR

2007-06-21

Jun 21, 2007 ... Model evolution; protein modelling; residue contact prediction; secondary structure prediction. Abbreviations used: ... set of sequence data (NR) and calculated conservation index of each ... evaluators (Moult et al 2003) to evaluate these model ... (Siew et al 2000), is a measure aims at identifying the largest.

Development of gypsy moth (Lymantria dispar L on the foliage of Quercus cerris L., Q. Petraea (matt Liebl. and Q. Robur L. in the controlled conditions

Directory of Open Access Journals (Sweden)

Milanović Slobodan

2007-01-01

Full Text Available The development of Gypsy moth (Lymantria dispar L was monitored in laboratory conditions, on the foliage of the species Quercus cerris L. Quercus petraea (Matt Liebl. and Quercus robur L. The experiment was established in the controlled environmental conditions, at the temperature of 25°C, photoperiod 14:10 (day: night and relative humidity 70%. The objective of the research was to determine the suitability of the study host plant species for gypsy moth development. The study results show that Gypsy moth caterpillars cultivated on Q. petraea foliage had a lower survival, higher number of moultings, longer preadult development and lower fecundity, which makes this species less suitable compared to the other two. Gypsy moth caterpillars cultivated on Q. cerris foliage had the highest survival degree the lowest number of moultings, the shortest preadult development and the highest fecundity, which makes this species the most favourable for gypsy moth development. Q. robur was between the former two species in this respect.

Effect of temperature on the mortality and growth of the lobster (Homarus gammarus L. ) in its first year

Energy Technology Data Exchange (ETDEWEB)

Danielssen, D S; Iversen, S A [Statens Biologiske Stasjon, Floedevigen (Norway)

1976-01-01

Experiments were carried out with newly hatched lobster larvae at temperatures of 12/sup 0/, 14/sup 0/, 16/sup 0/, 18/sup 0/, 20/sup 0/ and 22/sup 0/C. After about two months the constant temperature of 14/sup 0/C was changed to a fluctuating temperature corresponding to that at a depth of 20m outside the station, which should simulate as closely as possible the lobsters' natural temperature environment in the sea. The initial temperature shock did not seem to cause increased mortality during the first few days. Seen over the whole experiment period, the mortality was greatest at 12/sup 0/C and at the natural temperature. A temperature difference of 2/sup 0/C between the individual batches was sufficient to give a significant time difference from hatching to the fourth stage. The frequency of moulting fell with falling temperature and increasing number of moults. Even at the same temperature there were great individual differences in rates of growth.

Seasonal variation and annual trends of metals and metalloids in the blood of the Little Penguin (Eudyptula minor).

Science.gov (United States)

Finger, Annett; Lavers, Jennifer L; Orbell, John D; Dann, Peter; Nugegoda, Dayanthi; Scarpaci, Carol

2016-09-15

Little Penguins (Eudyptula minor) are high-trophic coastal feeders and are effective indicators of bioavailable pollutants in their foraging zones. Here, we present concentrations of metals and metalloids in blood of 157 Little Penguins, collected over three years and during three distinct seasons (breeding, moulting and non-breeding) at two locations: the urban St Kilda colony and the semi-rural colony at Phillip Island, Victoria, Australia. Penguin metal concentrations were foremostly influenced by location (St Kilda>Phillip Island for non-essential elements) and differed among years and seasons at both locations, reflecting differences in seasonal metal bioaccumulation or seasonal exposure through prey. Mean blood mercury concentrations showed an increasing annual trend and a negative correlation with flipper length at St Kilda. Notably, this study is the first to report on blood metal concentrations during the different stages of moult, showing the mechanism of non-essential metal mobilisation and detoxification. Copyright © 2016 Elsevier Ltd. All rights reserved.

Effects of precocene and azadirachtin in Rhodnius prolixus: some data on development and reproduction

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Eloi S. Garcia

1987-01-01

Full Text Available The results presented in this paper clearly indicate that precocene and azadirachtin are effective inhibitors of moulting and reproduction in the hemipteran Rhodnius prolixus. The time of application is important and only applications of these substances early in the intermoulting period cause their effects in nymphs. The inhibition of moulting is fully reversed by ecdysone therapy. Precocene and azadirachtin also affected drastically the oogenesis and egg deposition in this insect. Precocene-induced sterilization is reversed by application of juvenile hormone III. However, this hormone is unable to reverse the effect of azadirachtin on reproduction. Ecdysteroid titers in nymphs and adult females are decreased by these treatments. In vitro analysis suggest that precocene and azadirachtin may act directly on the prothoracic glands and ovaries producing ecdysteroids. Based on these and other findings the possible mode of action of these compounds on the development and reproduction of Rhodnius prolixus is discussed.

Energetic and developmental costs of mounting an immune response in greenfinches (Carduelis chloris)

NARCIS (Netherlands)

Amat, Juan A.; Aguilera, Eduardo; Visser, G. Henk

It is assumed that there is a trade-off between the costs allocated to mounting an immune defence and those allocated to costly functions such as breeding and moulting. The physiological basis for this is that mounting an immune response to pathogen challenge has energetic and/or nutrient costs

The effect of experience on the hunting success of newly emerged spiderlings.

Science.gov (United States)

Morse

2000-12-01

Initial interactions with prey may affect a predator's subsequent foraging success. With experience, second-instar Misumena vatia spiderlings (Thomisidae) that had recently emerged from their egg sacs oriented faster to fruit flies (Drosophila melanogaster) than näive individuals. Orientation time of these spiderlings decreased rapidly for the first two to three runs (every third day) in a simple laboratory setting, and then remained low and relatively constant. Time to capture a fly also declined initially, but subsequently became extremely variable, increasing prior to moult. Increase in capture time and the failure to capture prey appeared associated with impending moult, rather than satiation. Spiderlings oriented to prey more rapidly at the beginning of the third instar than at the start of the second instar, suggesting that experience still enhanced performance after a moult cycle. Overall capture times at the beginning of the third instar decreased from those at the end of the second instar, but did not differ significantly from the beginning of the second instar, although spiderlings gaining the most biomass had the shortest mean capture times. In a second experiment, time to orient and time to capture prey did not differ in näive, second-instar siblings run 1 and 3 days after emergence from their egg sacs. However, 3-day individuals that had captured prey each day (confiscated before they could feed) oriented faster than näive 3-day-old siblings, but did not differ in the time taken to capture prey. Experience, rather than age or energetic condition, best explains these changes in performance. Copyright 2000 The Association for the Study of Animal Behaviour.

Early life stages of Northern shrimp (Pandalus borealis) are sensitive to fish feed containing the anti-parasitic drug diflubenzuron.

Science.gov (United States)

Bechmann, Renée Katrin; Lyng, Emily; Westerlund, Stig; Bamber, Shaw; Berry, Mark; Arnberg, Maj; Kringstad, Alfhild; Calosi, Piero; Seear, Paul J

2018-05-01

Increasing use of fish feed containing the chitin synthesis inhibiting anti-parasitic drug diflubenzuron (DFB) in salmon aquaculture has raised concerns over its impact on coastal ecosystems. Larvae of Northern shrimp (Pandalus borealis) were exposed to DFB medicated feed under Control conditions (7.0 °C, pH 8.0) and under Ocean Acidification and Warming conditions (OAW, 9.5 °C and pH 7.6). Two weeks' exposure to DFB medicated feed caused significantly increased mortality. The effect of OAW and DFB on mortality of shrimp larvae was additive; 10% mortality in Control, 35% in OAW, 66% in DFB and 92% in OAW + DFB. In OAW + DFB feeding and swimming activity were reduced for stage II larvae and none of the surviving larvae developed to stage IV. Two genes involved in feeding (GAPDH and PRLP) and one gene involved in moulting (DD9B) were significantly downregulated in larvae exposed to OAW + DFB relative to the Control. Due to a shorter intermoult period under OAW conditions, the OAW + DFB larvae were exposed throughout two instead of one critical pre-moult period. This may explain the more serious sub-lethal effects for OAW + DFB than DFB larvae. A single day exposure at 4 days after hatching did not affect DFB larvae, but high mortality was observed for OAW + DFB larvae, possibly because they were exposed closer to moulting. High mortality of shrimp larvae exposed to DFB medicated feed, indicates that the use of DFB in salmon aquaculture is a threat to crustacean zooplankton. Copyright © 2018 The Authors. Published by Elsevier B.V. All rights reserved.

Temporal overlap and repeatability of feather corticosterone levels: practical considerations for use as a biomarker.

Science.gov (United States)

Harris, Christopher M; Madliger, Christine L; Love, Oliver P

2016-01-01

The measurement of corticosterone (CORT) levels in feathers has recently become an appealing tool for the conservation toolbox, potentially providing a non-invasive, integrated measure of stress activity throughout the time of feather growth. However, because the mechanism of CORT deposition, storage and stability in feathers is not fully understood, it is unclear how reliable this measure may be, especially when there is an extended interval between growth and feather collection. We compared CORT levels of naturally grown feathers from tree swallows ( Tachycineta bicolor ) that were moulted and regrown concurrently and therefore expected to have similar CORT levels. Specifically, we compared the same feather from the left and right wing (moulted symmetrically) and different types of feathers (wing, back and tail) expected to have been moulted within the same time period. We found that larger, heavier feathers held more CORT per unit length. In addition, we found a lack of concordance in CORT levels both within the same feather type and between different feather types, even after taking into account differences in feather density. Our results indicate that naturally grown feathers may not consistently provide an indication of stress status. Additionally, conflict in results may arise depending on the feather assayed, and total feather volume may be an important consideration when interpreting feather CORT levels. Future work is necessary to determine explicitly the mechanisms of CORT deposition, the effects of environmental exposure and feather wear on the permanence of the feather CORT signal, and the influence of responses to wild stressors on feather CORT levels, before feather CORT can be implemented effectively as a tool for ecological and conservation applications.

Relative feather mass indices: are feather masses needed to ...

African Journals Online (AJOL)

Relative feather mass indices: are feather masses needed to estimate the percentage of new feather mass grown for moult regression models? ... As an alternative, it is here tested if feather mass indices may be sufficient replacements for species-specific feather masses. Thirty-five species of birds with known primary ...

Barnacle geese Branta leucopsis on Nordenskioldkysten, western Spitsbergen - in thirty years from colonisation to saturation

NARCIS (Netherlands)

Drent, RH; Black, JM; Loonen, MJJE; Prop, J; Mehlum, F; Black, JM; Madsen, J

1998-01-01

Goose surveys on Nordenskioldkysten, a 40-km stretch centred at 78 degrees N on the western shoreline of Spitsbergen, were undertaken during 13 seasons in the period 1975-97. The surveys show that peak numbers of adults and goslings during the moult period July-August have flattened out since 1986.

The status of seabirds at Latham Island, Tanzania | Crawford ...

African Journals Online (AJOL)

Information is presented on moult, measurements of birds, eggs and nests, and on the construction and densities of nests. The plateau of the island was not substantially modified by the Indian Ocean tsunami of 26 December 2004, but the structure of the surrounding beach changed noticeably between the two surveys.

81 _ 86

African Journals Online (AJOL)

A rise ofecdysteroid titre towards the end of Iiflh instar apparently terminates feeding and stimulates cocoon spinning in preparation to the metamorphosis. For proper course of these developmental events, it is significant that the ecdysteroid level is slightly elevated for 1-2 days before rising to the moult inducing height. The.

The southern elephant seal Mirounga leonina at Gough Island

African Journals Online (AJOL)

haul-out in December coincided with the elephant seal moulting season, the elephant seals were found on the vegetated areas whilst the majority of fur seals hauled out onto the boulder beach. No interactions between the two species were recorded. Potential predators of elephant seals, i.e. the killer whales Orcinus orca ...

Effects of 5-Gy irradiation on fertility and mating behaviour of Nezara viridula (Heteroptera: Pentatomidae)

International Nuclear Information System (INIS)

Zunic, A.; Cokl, A.; Sersa, G.

2002-01-01

Background. The polyphagous and cosmopolitan species Nezara viridula is one of the most important insect pests. The sterile insect technique (SIT) is a pest control strategy that involves sterilising males by exposing them to ionising radiation. Sterile males, released into wild population, mate with females, but eggs are not fertilised and the population gradually declines. Exposing insects to radiation during their growth stage might require lower sterilising dose. The aim of our study was to test whether 5-Gy irradiation of 5 th instar nymphs significantly affects: (1) moulting and further development of the irradiated nymphs, (2) the male's and female's reproductive system and (3) the mating competitiveness of treated males, with special focus on vibrational communication. Methods: The 5 th instar nymphs were irradiated with 5 Gy using X-ray generator and monitored daily. Results: The observed effects of irradiation were: prolonged moulting, increased mortality during development and during the first day of adult life, decreased males to females ratio, decreased fecundity, egg production, proportion of fertile eggs and progeny survival. The reaction of a male to stimulation with the model female calling song was tested. The irradiated and non-irradiated males responded to stimulation with emission of the courtship song (MCrS). Temporal parameters of MCrS emitted by non-irradiated males differed when compared with those of irradiated ones. Conclusions: The 5-Gy irradiation of 5 th instar nymphs did not affect mating behaviour. However since the irradiation during growth stage decreased the fertility and fecundity of emerged adults, this technique, in combination with certain other suppression techniques, could be a successful control strategy for management of Nezara viridula. On the other hand observed effects on moulting and further development of the irradiated nymphs could decrease the efficiency and application of this strategy. (author)

Temperature and salinity tolerance of adult hermit crabs, Diogenes ...

African Journals Online (AJOL)

1987-11-04

Nov 4, 1987 ... estuary may not limit the distribution of hermit crabs. Because of their broad tolerance they should be able to survive near the head of the estuary. However, this continuous exposure to low salinity may be intolerable during moult and limit normal growth and metamorphosis, so although there may not be a.

Analýza stabilních izotopů – alternativní metoda studia migrace ptáků

Czech Academy of Sciences Publication Activity Database

Procházka, Petr

2006-01-01

Roč. 42, - (2006), s. 3-21 ISSN 0231-7796 R&D Projects: GA AV ČR KJB600930508 Institutional research plan: CEZ:AV0Z60930519 Keywords : bird migration * dispersal * moult patterns * movements * natal origin * stable isotop Subject RIV: EG - Zoology http://www. bird life.cz/wpimages/other/sylvia42-1Prochazka.pdf

Over het effect van hyperthyreoidiseering bij witte leghorns

NARCIS (Netherlands)

Meulen, van der J.B.

1938-01-01

Oral feeding of White Leghorn hens on a thyroid preparation generally had only a very small toxic effect when given in one dose. A higher death rate occurred when given in small doses on consecutive days.

The hens fell into a moult, varying from slight to complete, 7 or 8 days after thyroid

The African penguin Spheniscus demersus is endemic to the coasts ...

African Journals Online (AJOL)

denise

By the early 1990s, Mercury and. Ichaboe islands ... to estimate the number of birds moulting per year. Counts of active ... Mercury Island is the only Namibian breeding site where penguin numbers are .... Numbers fell abruptly in 1994, increased in 1995 and .... low levels of oxygen off central Namibia in 1994 caused fish ...

Endocrine basis of the reproductive pattern of the Gentoo penguin (Pygoscelis papua): winter breeding and extended laying period in northern populations.

Science.gov (United States)

Mauget, R; Garcia, V; Jouventin, P

1995-05-01

Changes in plasma LH, prolactin, testosterone, estradiol, and progesterone were investigated throughout moult and reproduction in free-living male and female Gentoo penguins (Pygoscelis papua) at Crozet Island (46 degrees S, 51 degrees E), where this species is able to relay after a reproductive failure. In both sexes, LH, prolactin, and steroid hormones, remained at basal levels during the moult. LH level was highest at the time of arrival at the colony for breeding and, although it decreased after courtship, it did not drop at basal value by incubation and first chick brooding period. Prolactin peaked for both chick brooding periods; replacement clutch was associated with an increased secretion of LH, whereas high prolactin levels were maintained. Testosterone, in male, and estradiol, in female, peaked during courtship I and chick brooding II; progesterone, in female, peaked during courtship I and II. These hormonal patterns are consistent with those observed in passerine species which are also able to relay after a reproductive failure. Winter breeding observed at Crozet Island might reflect the extreme adaptive capacity of Gentoo penguin species.

Feeding habits of the false southern king crab Paralomis granulosa (Lithodidae in the Beagle Channel, Tierra del Fuego, Argentina

Directory of Open Access Journals (Sweden)

Laura Inés Comoglio

1999-12-01

Full Text Available Stomach contents of 282 false southern king crabs (Paralomis granulosa, between 10 to 90 mm CL from the Beagle Channel (Golondrina Bay and Roca Mora, Argentina, were examined by the frequency of occurrence method of analysis and by a food index. Roca Mora is an area where juveniles ( 60 mm CL are common; in this last area sexual segregation was also observed. The principal food groups for crabs of Golondrina Bay were algae, molluscs, crustaceans, bryozoans and foraminiferans; for crabs from Roca Mora the natural diet consisted of three major food groups: hydrozoans, echinoderms and foraminiferans. The relative frequency of different prey groups varied in relation to the size, season and sex. There were no significant differences in the quantity of food consumed by sexes in both areas. Generally small crabs ( 50 mm CL. Juveniles consumed a greater amount of food during winter and spring. In summer (moulting period, juveniles had the highest vacuity index. Adults consumed minor amounts of food during autumn, before the spawning-moulting-mating period when the vacuity index was higher (spring.

Data Farming in Support of NATO

Science.gov (United States)

2014-03-01

rJos, C.A. Moul\\t ·c.ampbell, •nd S.A. Irani, "An •PP~"O• cll to Lhe design of a manufacturl.ng cell unde-r economic consldeflltk)fu. "’ Int. J...analysis and presentation of data at some level. Data farming, though, is a new paradigm that stemmed , to a large degree, from the pervasive availability

Size, plumage, moult and supposed hybrids of African Goshawks ...

African Journals Online (AJOL)

The male is even more variable in colour, in part age related: a 'sepia' morph is described for the first adult plumage. Older birds are grey with reddish flanks, becoming darker with age. The adult evergreen forest canescens shows enforcement of colourful advertising plumage and loss of sexual plumage dimorphism.

Status, biometrics, moult and possible relationships of the South ...

African Journals Online (AJOL)

The breeding population of Roseate Terns in southern Africa was estimated to be 250–260 pairs in 2000. Adult birds caught during nocturnal tern roost mist-netting on Bird Island and at Cape Recife, both in Algoa Bay, were closest to their North Atlantic counterparts in wing, bill, total head length, tail and mass ...

POSSIBILITIES OF CULTURING BIG SEA CRABS (LOBSTERS, SPINY LOBSTERS

Directory of Open Access Journals (Sweden)

Ivančica Strunjak-Perović

1999-09-01

Full Text Available By the end of the 19 th century an experimental work on culturing big sea crabs began in Europe and North America. Great demand for their flesh as well as their high price urged many institutions to explore the possibilities of a commercial production in varios parts of the world. Lobsters (Homarus sp. were mainly used for experimenting, so that the most data available refer to them. Because of the complicated larva stage spiny lobster culturing is mainly being carried out in experimental circumstances. Despite the promissing results this aquacultural activity faces many problems (long time until they achieve a commercial size, loss of eggs due to stress sensitivity during the process of moulting, canibalism. In order to minimize these problems various researches are being carried out, like temperature influence, influence of light, way of feeding, hormonal regulation of moulting frequency. Although both lobster and spiny lobsters live in the Adriatic Sea, there are no data on their culturing in our contry. Concernig conditions in our sea there are realistic possibilities for crabs production development. In this way this delicacy would be more affordable to broader population and could be a highly rated export product.

Temporal variation in the prevalence of the crayfish plague pathogen, Aphanomyces astaci, in three Czech spiny-cheek crayfish populations

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Matasová K.

2011-06-01

Full Text Available North American crayfish species are natural hosts of the crayfish plague pathogen Aphanomyces astaci. The spiny-cheek crayfish Orconectes limosus, widespread in Central Europe, is the main reservoir of A. astaci in Czech Republic. We tested if there are temporal changes in the prevalence of infected individuals (i.e., the proportion of individuals in which the pathogen is detected in spiny-cheek crayfish populations. Crayfish from three populations shown previously to be infected to different extents (high, intermediate and low, were repeatedly sampled in different years (2004–2010 and seasons. The presence of A. astaci in the soft abdominal crayfish cuticle was tested by specific amplification of the pathogen DNA. There was no substantial temporal variation in pathogen prevalence in the highly and very lowly infected populations. However, a significant long-term as well as seasonal decrease was found in the intermediately infected population. This decline could be related to a decrease in population density over the studied years, and to crayfish seasonal moulting, respectively. A reliable estimate of pathogen prevalence in American crayfish populations thus requires repeated monitoring over years, preferably during the same season before the main period of crayfish moulting.

The accumulation of plutonium by the European lobster (Homarus gammarus L.)

International Nuclear Information System (INIS)

Swift, D.J.

1992-01-01

For 237 Pu accumulation from seawater, the whole body concentration factors (CFs) for juvenile lobsters at 18 o C did not exceed 250 over the 49 days of the study. Most 237 Pu was accumulated by the gills and exoskeleton. Since homarid lobsters eat their exuviae after ecdysis, the whole body 237 Pu content of recently moulted lobsters was also a function of the amount of 237 Pu ingested with the exuviae. Consequently, organ/tissue content and CF values for individual lobsters reflected both the time since their last moult and their exposure time to 237 Pu. These factors precluded the calculation of mean whole body CF values or the accurate estimate of a mean steady state (C ss ) CF value. Juvenile lobsters retained significantly more 237 Pu from labelled food at 7-10 o C than at 18 o C. At 7 o C, the biological half time for assimilated 237 Pu was about 28 days, at 10 o C about 15 days and at 18 o C about 8 days. Very little 237 Pu was transported from the gut to the internal tissues (about 1%); most was retained in the hepatopancreas. (author)

Proteomic analysis of Oesophagostomum dentatum (Nematoda during larval transition, and the effects of hydrolase inhibitors on development.

Directory of Open Access Journals (Sweden)

Martina Ondrovics

Full Text Available In this study, in vitro drug testing was combined with proteomic and bioinformatic analyses to identify and characterize proteins involved in larval development of Oesophagostomum dentatum, an economically important parasitic nematode. Four hydrolase inhibitors ο-phenanthroline, sodium fluoride, iodoacetamide and 1,2-epoxy-3-(pnitrophenoxy-propane (EPNP significantly inhibited (≥90% larval development. Comparison of the proteomic profiles of the development-inhibited larvae with those of uninhibited control larvae using two-dimensional gel electrophoresis, and subsequent MALDI-TOF mass spectrometric analysis identified a down-regulation of 12 proteins inferred to be involved in various larval developmental processes, including post-embryonic development and growth. Furthermore, three proteins (i.e. intermediate filament protein B, tropomyosin and peptidyl-prolyl cis-trans isomerase inferred to be involved in the moulting process were down-regulated in moulting- and development-inhibited O. dentatum larvae. This first proteomic map of O. dentatum larvae provides insights in the protein profile of larval development in this parasitic nematode, and significantly improves our understanding of the fundamental biology of its development. The results and the approach used might assist in developing new interventions against parasitic nematodes by blocking or disrupting their key biological pathways.

Multiple exposure routes of a pesticide exacerbate effects on a grazing mayfly.

Science.gov (United States)

Pristed, Mathias Joachim Skov; Bundschuh, Mirco; Rasmussen, Jes Jessen

2016-09-01

Hydrophobic pesticides such as pyrethroid insecticides tend to occur in their soluble form mainly as transient pulses in streams. In addition, they are regularly detected in significant quantities adsorbed to stream sediments and other organic in-stream structures. Consequently, stream biota is likely subjected to pesticide exposure via multiple routes. In this study we aimed at investigating the influence of exposure routes for the pyrethroid insecticide lambda-cyhalothrin on the grazing mayfly Heptagenia sulphurea. Therefore, H. sulphurea was exposed to lambda-cyhalothrin via single- (water or biofilm) or biphasic exposure (water and biofilm) at environmentally realistic concentrations (0, 0.1, 1μgL(-1)) and exposure duration (2h) in a full factorial design (n=5). Mortality, moulting frequency, and biofilm accrual (proxy for feeding rate) were recorded subsequent to a 7 d post exposure period. Mortality significantly increased and moulting frequency significantly decreased with increasing concentrations of lambda-cyhalothrin in the water phase whereas exposure via biofilm prompted no significant effects on these endpoints (α=0.05). Effect predictions systematically underestimated and overestimated effects for mortality and moulting frequency, respectively. Similarly, mayfly feeding rate was significantly reduced by water phase exposure whereas pre-exposed biofilm did not significantly affect this variable. However, we found a significant but non-systematic interaction between water phase and biofilm exposure on mayfly feeding rate. Our results show that exposure to the same pesticide via multiple exposure routes may increase the magnitude of effects beyond the level predicted from single phase exposures which has clear implications for the aquatic risk assessment of hydrophobic pesticides. However, our results additionally reveal that interactions between pesticide exposure routes may vary between selected dependent variables. We emphasize that unravelling the

Application of synchrotron radiation phase-contrast microtomography with iodine staining to Rhodnius prolixus head during ecdysis period

Science.gov (United States)

Sena, G.; Nogueira, L. P.; Braz, D.; Colaço, M. V.; Azambuja, P.; Gonzalez, M. S.; Tromba, G.; Mantuano, A.; Costa, F. N.; Barroso, R. C.

2018-05-01

Synchrotron radiation phase-contrast microtomography (SR-PHC-CT) has become an important tool in studies of insects, mainly Rhodinius prolixus, the insect vector of Chagas disease. A previous work has shown that SR-PHC-CT is an excellent technique in studies about the ecdysis process of R.prolixus head. The term ecdysis refers to the set of behaviors by which an insect extracts itself from an old exoskeleton. The exoskeleton formation is indispensable for the evolutionary success of insect species, so failure to complete ecdysis will, in most cases result in death, making this process an excellent target in the search for new insect pest management strategies. Understanding the behavior of the ecdysis process is fundamental for the non-proliferation of Chagas disease. Despite it has been possible to identify the moulting process in the first work, main structures of the R.prolixus head could not be identified. In this work, it was developed a staining protocol which enabled the identification of these important structures using Iodine at SYRMEP beamline of ELETTRA. In the 3D images, it was possible to segment essential structures in the process of ecdysis. These structures have never been presented previously in the moulting period with SR-PHC-CT.

The accumulation of plutonium by the European lobster (Homarus gammarus L. )

Energy Technology Data Exchange (ETDEWEB)

Swift, D J [Ministry of Agriculture, Fisheries and Food, Lowestoft (United Kingdom). Directorate of Fisheries Research

1992-01-01

For {sup 237}Pu accumulation from seawater, the whole body concentration factors (CFs) for juvenile lobsters at 18{sup o}C did not exceed 250 over the 49 days of the study. Most {sup 237}Pu was accumulated by the gills and exoskeleton. Since homarid lobsters eat their exuviae after ecdysis, the whole body {sup 237}Pu content of recently moulted lobsters was also a function of the amount of {sup 237}Pu ingested with the exuviae. Consequently, organ/tissue content and CF values for individual lobsters reflected both the time since their last moult and their exposure time to {sup 237}Pu. These factors precluded the calculation of mean whole body CF values or the accurate estimate of a mean steady state (C{sub ss}) CF value. Juvenile lobsters retained significantly more {sup 237}Pu from labelled food at 7-10{sup o}C than at 18{sup o}C. At 7{sup o}C, the biological half time for assimilated {sup 237}Pu was about 28 days, at 10{sup o}C about 15 days and at 18{sup o}C about 8 days. Very little {sup 237}Pu was transported from the gut to the internal tissues (about 1%); most was retained in the hepatopancreas. (author).

The crucial role of cyclic GMP in the eclosion hormone mediated signal transduction in the silkworm metamorphoses.

Science.gov (United States)

Shibanaka, Y; Hayashi, H; Okada, N; Fujita, N

1991-10-31

The signal transduction of the peptide, eclosion hormone, in the silkworm Bombyx mori appears to be mediated via the second messenger cyclic GMP throughout their life cycle. Injection of 8-bromo-cGMP induced the ecdysis behavior in pharate adults with similar latency to eclosion hormone-induced ecdysis; the moulting occurred 50-70 min after the injection. The potency of 8Br-cGMP was 10(2) fold higher than that of cGMP and the efficacy was increased by the co-injection of the phosphodiesterase inhibitor IBMX. On the other hand, in the silkworm pupal ecdysis the eclosion hormone and also 8Br-cGMP induced the moulting behavior in a dose-dependent manner. The adult development of the ability to respond to 8Br-cGMP took place concomitantly with the response to the eclosion hormone. Both the developmental time courses were shifted by a shift of light and dark cycles. Accordingly, the sensitivities to the peptide and cyclic nucleotide developed correspondently under the light and dark circadian rhythm. Thus throughout the silkworm life cycle, eclosion hormone is effective to trigger the ecdysis behavior and cGMP plays a crucial role as the second messenger in the eclosion hormone-mediated signal transduction.

The Little Penguin (Eudyptula minor) as an indicator of coastal trace metal pollution

International Nuclear Information System (INIS)

Finger, Annett; Lavers, Jennifer L.; Dann, Peter; Nugegoda, Dayanthi; Orbell, John D.; Robertson, Bruce; Scarpaci, Carol

2015-01-01

Monitoring trace metal and metalloid concentrations in marine animals is important for their conservation and could also reliably reflect pollution levels in their marine ecosystems. Concentrations vary across tissue types, with implications for reliable monitoring. We sampled blood and moulted feathers of the Little Penguin (Eudyptula minor) from three distinct colonies, which are subject to varying levels of anthropogenic impact. Non-essential trace metal and metalloid concentrations in Little Penguins were clearly linked to the level of industrialisation adjacent to the respective foraging zones. This trend was more distinct in blood than in moulted feathers, although we found a clear correlation between blood and feathers for mercury, lead and iron. This study represents the first reported examination of trace metals and metalloids in the blood of any penguin species and demonstrates that this high trophic feeder is an effective bioindicator of coastal pollution. - Highlights: • Trace metals measured in blood and feathers. • Arsenic, Mercury and Lead significantly higher at urban colony. • Correlations found between trace metals in feathers and blood. • Little Penguins are suitable bioindicators for coastal metal pollution. - This study confirms the suitability of the Little Penguin as a bioindicator of coastal metal pollution in coastal areas using non-destructive sampling methods

Climate change is affecting mortality of weasels due to camouflage mismatch.

Science.gov (United States)

Atmeh, Kamal; Andruszkiewicz, Anna; Zub, Karol

2018-05-24

Direct phenological mismatch caused by climate change can occur in mammals that moult seasonally. Two colour morphs of the weasel Mustela nivalis (M. n.) occur sympatrically in Białowieża Forest (NE Poland) and differ in their winter pelage colour: white in M. n. nivalis and brown in M. n. vulgaris. Due to their small body size, weasels are vulnerable to attacks by a range of different predators; thus cryptic coat colour may increase their winter survival. By analysing trapping data, we found that the share of white subspecies in the weasel population inhabiting Białowieża Forest decreases with decreasing numbers of days with snow cover. This led us to hypothesise that selective predation pressure should favour one of the two phenotypes, according to the prevailing weather conditions in winter. A simple field experiment with weasel models (white and brown), exposed against different background colours, revealed that contrasting models faced significantly higher detection by predators. Our observations also confirmed earlier findings that the plasticity of moult in M. n. nivalis is very limited. This means that climate change will strongly influence the mortality of the nivalis-type due to prolonged camouflage mismatch, which will directly affect the abundance and geographical distribution of this subspecies.

Differential effects of endoparasitism on the expression of carotenoid- and melanin-based ornamental coloration.

OpenAIRE

McGraw, K J; Hill, G E

2000-01-01

The striking diversity of sexual dimorphisms in nature begs the question: Why are there so many signal types? One possibility is that ornamental traits convey different sets of information about the quality of the sender to the receiver. The colourful, pigmented feathers of male birds seem to meet the predictions of this hypothesis. Evidence suggests that carotenoid pigmentation reflects the nutritional condition of males during moult, whereas in many instances melanin pigmentation is a relia...

Ontogeny of thermoregulation and energy metabolism in pygoscelid penguin chicks.

Science.gov (United States)

Taylor, J R

1985-01-01

The ontogeny of thermoregulation and energy metabolism of chinstrap (Pygoscelis antarctica) and gentoo (P. papua) penguins was studied on King George Island, South Shetland Island, Antarctica. The major findings of this study are: Chinstrap and gentoo penguin chicks hatched completely poikilothermic, due to their poor heat-production ability at low ambient temperatures. They were able to maintain high body temperatures and metabolic rates only by being brooded by adults. Newly hatched chinstrap penguin chicks had, at a specified ambient temperature, significantly higher metabolic rates than newly hatched gentoos. Moreover, chinstrap chicks maintained a significantly higher body temperature. It is suggested that this is a non-acclimatory metabolic adaptation of chinstrap penguin chicks to the lower mean temperatures of their breeding areas. On the 15th day after hatching, chinstrap chicks were completely, and gentoo chicks almost completely, homeothermic. In spite of their high thermogenic capacity from about day 10, chicks were not at that time capable of controlling heat dissipation, and were still dependent on their parents. In older downy chicks and fledglings, heat loss at low temperatures, expressed as heat conductance (CA), was similar to that found for the adults of other penguin species. Just before moulting the CA of chicks was lower than after moulting. Moulting alone did not cause a clear increase in CA. Towards the end of their stay on land the CA of pre-fledged gentoos decreased by 31%. This decrease was not connected with the development of feathers or growth in the chicks' weight. The combination of the low CA and high SMR of chicks gave very low lower critical temperatures, near -15 degrees C. The wide thermoneutral zones of the chicks covered the whole range of air temperature variations in the breeding colonies of both species studied on King George Island. The CA values of homeothermic chinstrap chicks were not lower than those of gentoos

Validating the use of intrinsic markers in body feathers to identify inter-individual differences in non-breeding areas of northern fulmars.

Science.gov (United States)

Quinn, Lucy R; Meharg, Andrew A; van Franeker, Jan A; Graham, Isla M; Thompson, Paul M

Many wildlife studies use chemical analyses to explore spatio-temporal variation in diet, migratory patterns and contaminant exposure. Intrinsic markers are particularly valuable for studying non-breeding marine predators, when direct methods of investigation are rarely feasible. However, any inferences regarding foraging ecology are dependent upon the time scale over which tissues such as feathers are formed. In this study, we validate the use of body feathers for studying non-breeding foraging patterns in a pelagic seabird, the northern fulmar. Analysis of carcasses of successfully breeding adult fulmars indicated that body feathers moulted between September and March, whereas analyses of carcasses and activity patterns suggested that wing feather and tail feather moult occurred during more restricted periods (September to October and September to January, respectively). By randomly sampling relevant body feathers, average values for individual birds were shown to be consistent. We also integrated chemical analyses of body feather with geolocation tracking data to demonstrate that analyses of δ 13 C and δ 15 N values successfully assigned 88 % of birds to one of two broad wintering regions used by breeding adult fulmars from a Scottish study colony. These data provide strong support for the use of body feathers as a tool for exploring non-breeding foraging patterns and diet in wide-ranging, pelagic seabirds.

Occurrence of Hepatozoon canis and Cercopithifilaria bainae in an off-host population of Rhipicephalus sanguineus sensu lato ticks.

Science.gov (United States)

Ramos, Rafael Antonio Nascimento; Giannelli, Alessio; Carbone, Domenico; Baneth, Gad; Dantas-Torres, Filipe; Otranto, Domenico

2014-04-01

Hepatozoon canis (Eucoccidiorida, Hepatozoidae) and the filarioid Cercopithifilaria bainae (Spirurida, Onchocercidae) are tick-transmitted infectious agents of dogs, highly prevalent in the Mediterranean basin in association with Rhipicephalus sanguineus sensu lato. Ticks were collected from the environment every 25±2 days in a confined location in southern Italy where a community of dogs lives, from August 2012 to July 2013. In order to study the occurrence of H. canis and C. bainae, 1091 tick specimens (770 adults; 271 nymphs, and 50 larvae) were dissected, and oocysts of H. canis and larvae of C. bainae were morphologically identified. Out of 1091 dissected ticks, 13.47% (n=147) were positive for H. canis, with the highest prevalence recorded in unfed adults (16.4%; 126/770), followed by nymphs collected as larvae and allowed to moult (14%; 7/50), unfed nymphs dissected immediately after collection (3%; 8/271), and adults collected as nymphs and allowed to moult (2%; 6/271). The highest number of H. canis-positive ticks (35.5%; 43/121; Pcanis and C. bainae infections in the study area seem to be dependent on the seasonality of vector tick populations. Hence, dogs living in these areas are more exposed to both pathogens during the warmer months. These findings provide new insights into the ecology of both H. canis and C. bainae. Copyright © 2014 Elsevier GmbH. All rights reserved.

Low concentrations, potential ecological consequences: Synthetic estrogens alter life-history and demographic structures of aquatic invertebrates

International Nuclear Information System (INIS)

Souza, María Sol; Hallgren, Per; Balseiro, Esteban; Hansson, Lars-Anders

2013-01-01

Contraceptive drugs are nowadays found in aquatic environments around the globe. Particularly, 17α-ethinylestradiol (EE 2 ) may act even at low concentrations, such as those recorded in natural ecosystems. We evaluated the physiological effects of EE 2 on cyclopoids and calanoids, common copepods in both marine and freshwater communities. We used three EE 2 concentrations and assessed its impact on activity of different physiological endpoints: Acetylcholinesterase (neurotransmission), Glutathione S-transferase (detoxifying system), and Caspase-3 (apoptosis). While EE 2 exerts, distinctive effect on detoxifying and apoptotic systems, no effect on AChE was observed at environmental doses. Our results show that EE 2 exposure affects differently copepod physiology endpoints, altering moulting process, adult recruitment in calanoids and calanoid to cyclopoid ratio. The ecological consequences of this underlying physiological process may affect since life history to population and community structures, and this represent a new aspects of this xenobiotic in natural systems. Highlights: •We evaluated physiological effects of 17α-ethinylestradiol (EE 2 ) on copepods. •We measured the EE 2 effect on neurotransmission, detoxifying system and apoptosis. •EE 2 exert distinctive effect on detoxifying and apoptotic systems. •EE 2 affects differently calanoids and cyclopoids moulting and adult recruitment. •Physiological impact in invertebrates' communities is a novel aspect of EE 2 effects. -- Anthropogenic estrogens modify the physiological functioning of aquatic invertebrates

Role of Methoprene-tolerant (Met in adult morphogenesis and in adult ecdysis of Blattella germanica.

Directory of Open Access Journals (Sweden)

Jesus Lozano

Full Text Available Juvenile Hormone (JH represses metamorphosis of young instars in insects. One of the main players in hormonal signalling is Methoprene-tolerant (Met, which plays the role of JH receptor. Using the Polyneopteran insect Blattella germanica as the model and RNAi for transcript depletion, we have confirmed that Met transduces the antimetamorphic signal of JH in young nymphs and plays a role in the last nymphal instar moult in this species. Previously, the function of Met as the JH receptor had been demonstrated in the Eumetabola clade, with experiments in Holometabola (in the beetle Tribolium castaneum and in their sister group Paraneoptera (in the bug Pyrrhocoris apterus. Our result shows that the function of Met as JH receptor is also conserved in the more basal Polyneoptera. The function of Met as JH transducer might thus predate the evolutionary innovation of metamorphosis. Moreover, expression of Met was also found in last nymphal instar of B. germanica, when JH is absent. Depletion of Met in this stage provoked deficiencies in wing growth and ecdysis problems in the imaginal moult. Down-regulation of the ecdysone-inducible gene E75A and Insulin-Like-Peptide 1 in these Met-depleted specimens suggest that Met is involved in the ecdysone and insulin signalling pathways in last nymphal instar, when JH is virtually absent.

Gut fluorescence analysis of barnacle larvae: An approach to quantify the ingested food

Digital Repository Service at National Institute of Oceanography (India)

Gaonkar, C.A.; Anil, A.C.

of Oceanography, Dona Paula, Goa, India A B S T R A C T Gut fluorescence analysis can provide a snapshot of ingested food and has been employed in the feeding studies of various organisms. In this study we standardised the gut fluorescence method utilising... naupliar instars and a pre-settling cyprid instar. The I instar nauplius is non-feeding and moults into II instar within a short interval of time. II to VI instars are phytoplanktivorus. Nauplii obtained from the adult broods of the barnacle Balanus...

El genero Morpho en Colombia: II. Clave taxonómica para las especies presentes en Colombia The genus Morpho in Colombia: II.Taxonomic key for the species from Colombia

Directory of Open Access Journals (Sweden)

Rodríguez Claudia Luz

1996-06-01

Full Text Available Se presenta una clave dicotómica para determinar las diferentes especies de mariposas del género Morpho que habitan en Colombia, con ilustraciones sobre las genitalias de los principales subgéneros y fotografías (dorsal y ventral de los adultos más representativos de ambos sexos. Para la determinación taxonómica de las especies, se siguieron los parámetros propuestos por Clarke (1941 con algunas modificaciones que simplifican la utilización de esta técnica. También, se tuvieron en cuenta aspectos morfométricos alares, patrones de coloración alar y características de las genitalias de los machos; en
algunos casos, se recurrió a la consulta de la literatura de referencia (Le Moult y Real, 1962; Blandin, 1984.A dichotomous key is provided for determining the different species of butterflies of the genus Morpho from Colombia, with
ilustrations of the male genitalia and dorsal and ventral pictures of representative males and females of the main subgenera. For the study of the taxonomic characteristics of the species, the parameters given by Clarke (1941 were followed with some modifications that simplified the use of this technique. Wing
morphometrics and coloration patterns and mal e genitalia features were also included, in some cases, references of the literature were given (Le Moult & Real, 1962; Blandin, 1984.

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.

Three-dimensional reconstruction of the naupliar musculature and a scanning electron microscopy atlas of nauplius development of Balanus improvisus (Crustacea

DEFF Research Database (Denmark)

Semmler, Henrike; Høeg, Jens Thorvald; Scholtz, Gerhard

2009-01-01

, as is the setation pattern of the first antennae. The naupliar musculature of B. improvisus was stained with phalloidin to visualise F-actin, followed by analysis using confocal laser scanning microscopy (CLSM) with subsequent application of 3D imaging software. The larval musculature is already fully established......An atlas of the naupliar development of the cirripede Balanus improvisus Darwin, 1854 using scanning electron microscopy (SEM) is provided. Existing spikes on the hindbody increase in number with each moult and are an applicable character for identification of the different nauplius stages...

Effects of short- and long-term exposures to copper on lethal and reproductive endpoints of the harpacticoid copepod Tigriopus fulvus.

Science.gov (United States)

Biandolino, Francesca; Parlapiano, Isabella; Faraponova, Olga; Prato, Ermelinda

2018-01-01

The long-term exposure provides a realistic measurement of the effects of toxicants on aquatic organisms. The harpacticoid copepod Tigriopus fulvus has a wide geographical distribution and is considered as an ideal model organism for ecotoxicological studies for its good sensitivity to different toxicants. In this study, acute, sub-chronic and chronic toxicity tests based on lethal and reproductive responses of Tigriopus fulvus to copper were performed. The number of moults during larval development was chosen as an endpoint for sub-chronic test. Sex ratio, inhibitory effect on larval development, hatching time, fecundity, brood number, nauplii/brood, total newborn production, etc, were calculated in the chronic test (28d). Lethal effect of copper to nauplii showed the LC50-48h of 310 ± 72µgCu/L (mean ± sd). It was observed a significant inhibition of larval development at sublethal copper concentrations, after 4 and 7 d. After 4d, the EC50 value obtained for the endpoint in "moult naupliar reduction" was of 55.8 ± 2.5µgCu/L (mean ± sd). The EC50 for the inhibition of naupliar development into copepodite stage, was of 21.7 ± 4.4µgCu/L (mean ± sd), after 7 days. Among the different traits tested, copper did not affect sex ratio and growth, while fecundity and total nauplii production were the most sensitive endpoints. The reproductive endpoints offer the advantage of being detectable at very low pollutant concentrations. Copyright © 2017 Elsevier Inc. All rights reserved.

Undersøgelse af Vandrefalken i Sydgrønland

DEFF Research Database (Denmark)

Falk, Knud; Møller, Søren

2008-01-01

whole addled egg was collected, fragments from hatched eggs collected in 6 nests, and moulted feathers from the adults collected at 4 nests. Among 6 nests, the first egg hatched between 27 June and 6 July (mean 30th June) - a little earlier than the average (4 July) for 1981-2007).......This report presents results from the 26th field season of the project "Investigations of the Peregrine Falcon in South Greenland". Following analyses of data from the first 22 years, the primary objectives of the study since 2005 has shifted towards monitoring of a fixed sample of nesting sites...

Undersøgelse af Vandrefalken i Sydgrønland

DEFF Research Database (Denmark)

Falk, Knud; Møller, Søren

2013-01-01

in 6 nests, and moulted feathers from the adults collected at 4 nests. Among 9 nests, the first egg hatched between 1 July and 10 July (mean 4 July), one day later than the average for 1981-2012. In addition, five breeding female Peregrine Falcons were fitted with geolocators.......This report presents results from the 30th field season of the project “Investigations of the Peregrine Falcon in South Greenland”. Following analyses of data from the first 22 years, the primary objectives of the study since 2005 has shifted towards monitoring of a fixed sample of nesting sites...

Experimental dissociation of individual quality, food and timing of breeding effects on double-brooding in a migratory songbird.

Science.gov (United States)

O'Brien, Erin L; Dawson, Russell D

2013-07-01

Annual reproductive success in many species is influenced by the number of breeding attempts within a season. Although previous studies have shown isolated effects of female quality, food, and timing of breeding on the probability of female birds producing second broods, to our knowledge, none have tested the relative importance of multiple factors and their interactions using simultaneous manipulations within populations of free-living birds. In this study, we show that individual quality and timing of breeding interact to affect the probability of double-brooding in female mountain bluebirds (Sialia currucoides). High-quality females (those that naturally initiated clutches early in the season) were more likely to double-brood, regardless of whether their hatching date was advanced or delayed, whereas later breeding, lower quality females were much less likely to double-brood when their first attempt was delayed. This indicates that annual fecundity of poorer quality (or younger) female bluebirds may be more sensitive to seasonal variation in environmental conditions. In addition, birds that were provided with supplemental food throughout first breeding attempts were more likely to double-brood in one of the study years, suggesting that female bluebirds may be energetically limited in their capacity to initiate a second brood. Females that had their first brood delayed also had a shorter inter-brood interval and were moulting fewer feathers during second broods compared to controls, while females in better condition showed more advanced moult in second breeding attempts. Taken together, our results demonstrate the combined effects of age- or individual quality-mediated energetic trade-offs between current and future reproduction, and between investments in offspring and self-maintenance, on annual fecundity of female birds.

Antibiotic mixture effects on growth of the leaf-shredding stream detritivore Gammarus fossarum.

Science.gov (United States)

Bundschuh, Mirco; Hahn, Torsten; Gessner, Mark O; Schulz, Ralf

2017-05-01

Pharmaceuticals contribute greatly to human and animal health. Given their specific biological targets, pharmaceuticals pose a significant environmental risk by affecting organisms and ecosystem processes, including leaf-litter decomposition. Although litter decomposition is a central process in forest streams, the consequences of exposure to pharmaceuticals remain poorly known. The present study assessed the impact of antibiotics as an important class of pharmaceuticals on the growth of the leaf-shredding amphipod Gammarus fossarum over 24 days. Exposure scenarios involved an antibiotic mixture (i.e. sulfamethoxazole, trimethoprim, erythromycin-H 2 O, roxithromycin, clarithromycin) at 0, 2 and 200 µg/L to assess impacts resulting from exposure to both water and food. The antibiotics had no effect on either leaf-associated fungal biomass or bacterial abundance. However, modification of leaf quality (e.g. through shifts in leaf-associated microbial communities) may have triggered faster growth of gammarids (assessed in terms of body mass gain) at the low antibiotic concentration relative to the control. At 200 µg/L, however, gammarid growth was not stimulated. This outcome might be due to a modified ability of the gut microflora to assimilate nutrients and carbon. Furthermore, the observed lack of increases in the diameter of the gammarids' peduncles, despite an increase in gammarid mass, suggests antibiotic-induced effects in the moulting cycle. Although the processes responsible for the observed effects have not yet been identified, these results suggest a potential role of food-quality, gammarid gut microflora and alteration in the moulting cycle in mediating impacts of antibiotics on these detritivores and the leaf decomposition process in streams.

Lead exposure from lead pellets: age-related accumulation in mute swans

Energy Technology Data Exchange (ETDEWEB)

Eskildsen, J.; Grandjean, P.

1984-05-01

In a cross-sectional study of adult swans and their successfully fledged young in Ringkobing Fjord, West Jutland, Denmark, 128 venous blood samples were taken during the moulting period and analyzed for lead. While the juveniles generally showed blood lead levels below 15 micrograms/100 ml (median, 11 micrograms/100 ml), the values were significantly higher in adults (median, 25 micrograms/100 ml). Adult females showed slightly higher levels than did adult males. None of the birds examined showed signs of acute lead toxicity, and increased blood levels in adults may reflect increased lead body burdens from previous ingestion of lead shot as gizzard stones.

Moulting in the lobopodian Onychodictyon from the lower Cambrian of Greenland

DEFF Research Database (Denmark)

Topper, Timothy Paul; Skovsted, Christian B.; Peel, John S.

2013-01-01

A number of lobopodian taxa from the Cambrian display pairs of sclerotized plates symmetrically positioned along the dorsum of the animal, predominantly above the walking appendages. Most genera were described from complete body fossils exquisitely preserved in the famous Cambrian Lagerstatten, b...

Atlantic Seaduck Project

Science.gov (United States)

Perry, M.C.; Hanson, Alan; Kerekes, Joseph; Paquet, Julie

2006-01-01

Atlantic Seaduck Project is being conducted to learn more about the breeding and moulting areas of seaducks in northern Canada and more about their feeding ecology on wintering areas, especially Chesapeake Bay. Satellite telemetry is being used to track surf scoters wintering in Chesapeake Bay, Maryland and black scoters on migrational staging areas in New Brunswick, Canada to breeding and moulting areas in northern Canada. Various techniques used to capture the scoters included mist netting, night-lighting, and net capture guns. All captured ducks were transported to a veterinary hospital where surgery was conducted following general anaesthesia procedures. A PTT100 transmitter (39 g) manufactured by Microwave, Inc., Columbia, Maryland was implanted into the duck?s abdominal cavity with an external (percutaneous) antenna. Eight of the surf scoters from Chesapeake Bay successfully migrated to possible breeding areas in Canada and all 13 of the black scoters migrated to suspected breeding areas. Ten of the 11 black scoter males migrated to James Bay presumably for moulting. Updated information from the ARGOS Systems aboard the NOAA satellites on scoter movements was made accessible on the Patuxent Website. Habitat cover types of locations using GIS (Geographical Information Systems) and aerial photographs (in conjunction with remote sensing software) are currently being analyzed to build thematic maps with varying cosmetic layer applications. Many factors related to human population increases have been implicated in causing changes in the distribution and abundance of wintering seaducks. Analyses of the gullet (oesophagus and proventriculus) and the gizzard of seaducks are currently being conducted to determine if changes from historical data have occurred. Scoters in the Bay feed predominantly on the hooked mussel and several species of clams. The long-tailed duck appears to select the gem clam in greater amounts than other seaducks, but exhibits a diverse diet of

Larval salinity tolerance of the South American salt-marsh crab, Neohelice (Chasmagnathus) granulata: physiological constraints to estuarine retention, export and reimmigration

Science.gov (United States)

Anger, Klaus; Spivak, Eduardo; Luppi, Tomás; Bas, Claudia; Ismael, Deborah

2008-06-01

The semiterrestrial crab Neohelice (= Chasmagnathus) granulata (Dana 1851) is a predominant species in brackish salt marshes, mangroves and estuaries. Its larvae are exported towards coastal marine waters. In order to estimate the limits of salinity tolerance constraining larval retention in estuarine habitats, we exposed in laboratory experiments freshly hatched zoeae to six different salinities (5 32‰). At 5‰, the larvae survived for a maximum of 2 weeks, reaching only exceptionally the second zoeal stage, while 38% survived to the megalopa stage at 10‰. Shortest development and negligible mortality occurred at all higher salt concentrations. These observations show that the larvae of N. granulata can tolerate a retention in the mesohaline reaches of estuaries, with a lower limit of ca. 10 15‰. Maximum survival at 25‰ suggests that polyhaline conditions rather than an export to oceanic waters are optimal for successful larval development of this species. In another experiment, we tested the capability of the last zoeal stage (IV) for reimmigration from coastal marine into brackish waters. Stepwise reductions of salinity during this stage allowed for moulting to the megalopa at 4 10‰. Although survival was at these conditions reduced and development delayed, these results suggest that already the zoea-IV stage is able to initiate the reimmigration into estuaries. After further salinity reduction, megalopae survived in this experiment for up to >3 weeks in freshwater, without moulting to juvenile crabs. In a similar experiment starting from the megalopa stage, successful metamorphosis occurred at 4 10‰, and juvenile growth continued in freshwater. Although these juvenile crabs showed significantly enhanced mortality and smaller carapace width compared to a seawater control, our results show that the late larval and early juvenile stages of N. granulata are well adapted for successful recruitment in brackish and even limnetic habitats.

Effects of buprofezin on the ultrastructure of the third instar cuticle of the insect Trialeurodes vaporariorum.

Science.gov (United States)

De Cock, A; Degheele, D

1991-01-01

Treatment with buprofezin at the beginning of the third instar of Trialeurodes vaporariorum results in death of the larvae at the time of moulting. Electron microscopic observations, after treatment of the larvae with 20 mg a.i./l buprofezin, does not reveal any difference in the ultrastructural profile before apolysis, however formation of a normal lamellate procuticle is disturbed. The pharate procuticle is amorphous, varying in thickness and the mean thickness is greatly reduced. The subcuticle is interrupted several times at locations corresponding with the thinnest places of the pharate cuticle. Epidermal cells contain unusual structures such as myelin figures and hypertrophied mitochondria indicating that buprofezin may have an additional toxic effect on epidermal cells.

Differential moult patterns in relation to antipredator behaviour during incubation in four tundra plovers

NARCIS (Netherlands)

Jukema, J.; Tulp, I.Y.M.; Bruinzeel, L.

2003-01-01

Golden plovers and Grey Plovers Pluvialis spp. all have very distinct breeding plumage rich in contrast, with a conspicuous black belly and breast bordered by a bright white fringe. Eurasian Golden Plovers are known partly to replace their breeding plumage with striped yellow feathers during

Differential moult patterns in relation to antipredator behaviour during incubation in four tundra plovers

NARCIS (Netherlands)

Jukema, J; Tulp, Ingrid; Bruinzeel, Louis

Golden plovers and Grey Plovers Pluvialis spp. all have very distinct breeding plumage rich in contrast, with a conspicuous black belly and breast bordered by a bright white fringe. Eurasian Golden Plovers are known partly to replace their breeding plumage with striped yellow feathers during

Evaluation of in vitro culture systems for the maintenance of microfilariae and infective larvae of Loa loa.

Science.gov (United States)

Zofou, Denis; Fombad, Fanny Fri; Gandjui, Narcisse V T; Njouendou, Abdel Jelil; Kengne-Ouafo, Arnaud Jonas; Chounna Ndongmo, Patrick W; Datchoua-Poutcheu, Fabrice R; Enyong, Peter A; Bita, Dizzle Tayong; Taylor, Mark J; Turner, Joseph D; Wanji, Samuel

2018-05-02

Suitable and scalable in vitro culture conditions for parasite maintenance are needed to foster drug research for loiasis, one of the neglected tropical diseases which has attracted only limited attention over recent years, despite having important public health impacts. The present work aims to develop adequate in vitro culture systems for drug screening against both microfilariae (mf) and infective third-stage larvae (L3) of Loa loa. In vitro culture conditions were evaluated by varying three basic culture media: Roswell Park Memorial Institute (RPMI-1640), Dulbecco's modified Eagle's medium (DMEM) and Iscove's modified Dulbecco's medium (IMDM); four sera/proteins: newborn calf serum (NCS), foetal bovine serum (FBS), bovine serum albumin (BSA) and the lipid-enriched BSA (AlbuMax® II, ALB); and co-culture with the Monkey Kidney Epithelial Cell line (LLC-MK2) as a feeder layer. The various culture systems were tested on both mf and L3, using survival (% motile), motility (T 90 = mean duration (days) at which at least 90% of parasites were fully active) and moulting rates of L3 as the major criteria. The general linear model regression analysis was performed to assess the contribution of each variable on the viability of Loa loa L3 and microfilarie. All statistical tests were performed at 95% confidence interval. Of the three different media tested, DMEM and IMDM were the most suitable sustaining the maintenance of both L. loa L3 and mf. IMDM alone could sustain L3 for more than 5 days (T 90 = 6.5 ± 1.1 day). Serum supplements and LLC-MK2 co-cultures significantly improved the survival of parasites in DMEM and IMDM. In co-cultures with LLC-MK2 cells, L. loa mf were maintained in each of the three basic media (T 90 of 16.4-19.5 days) without any serum supplement. The most effective culture systems promoting significant moulting rate of L3 into L4 (at least 25%) with substantial maintenance time were: DMEM + BSA, DMEM + NCS, DMEM-AlbuMax®II, DMEM + FBS all in co

The early phyllosoma stages of spiny lobster Panulirus echinatus Smith, 1869 (Decapoda: Palinuridae reared in the laboratory

Directory of Open Access Journals (Sweden)

FA. Abrunhosa

Full Text Available The early stages of the Panulirus echinatus were hatched and reared in the laboratory. Ovigerous females were captured in their habitat and carefully transported to the laboratory. Larvae were transferred in a recirculation water tank at a density of 10 larvae.L-1. The larvae were fed on Artemia and gonads of mussel Brachydonts sp. Microalgae Dunaliella viridis was added at a concentration of 150 x 10(4 cell.mL-1. Larvae and exuviae of each zoeal stage were preserved in an alcohol 70% + glycerin (1:1 solution. The phyllosomas moulted eight times; the intermoulting period of each instar averaged about 7 to 10 days. The main morphological changes of each appendage were described in detail, illustrated and compared with previous reports.

Consistent habitat segregation between sexes in the spider crabs Maja brachydactyla and Maja squinado (Brachyura, as revealed by stable isotopes

Directory of Open Access Journals (Sweden)

Guillermo Guerao

2016-03-01

Full Text Available Differences in the resource use patterns of males and females of the spider crab species Maja brachydactyla Balss, 1922 and M. squinado (Herbst, 1788 from several geographic areas (three in the Atlantic and two in the Mediterranean were studied through the analysis of stable isotopes of carbon and nitrogen in the exoskeleton of post-pubertal (adult specimens. Results confirmed that males and females from the same population usually did not differ in δ15N values and hence foraged at the same trophic level. In contrast, females were usually enriched in 13C as compared with males from the same population, thus suggesting that females use shallower habitats than males before the terminal moult. The results reported here also indicate that stable isotop.

House-dust mites in our homes are a contamination from outdoor sources

DEFF Research Database (Denmark)

Hallas, Thorkil E.

2010-01-01

there and that the stages between them, the inactive moulting stages, are absent. Therefore the mites probably do not carry out their life cycles in our dwellings, but are more likely contaminations from the open. Findings of low level concentrations can be explained by mites coming from outdoors and sedimented......Avoidance advices for house-dust mite sensitized persons are currently based upon the idea, that the mites (Dermatophagoides spp.) are part of the indoor fauna. A closer look at development stages in the house-dust samples shows, however, that only the mites' active stages are present...... no effect of avoidance measures. The verification of the entire hypothesis or part of it may have great impact on the management of the disease house-dust mite allergy....

Transstadial Transmission of Hepatozoon canis by Rhipicephalus sanguineus (Acari: Ixodidae) in Field Conditions.

Science.gov (United States)

Aktas, M; Özübek, S

2017-07-01

This study investigated possible transovarial and transstadial transmission of Hepatozoon canis by Rhipicephalus sanguineus (Latreille) ticks collected from naturally infected dogs in a municipal dog shelter and the grounds of the shelter. Four hundred sixty-five engorged nymphs were collected from 16 stray dogs that were found to be infected with H. canis by blood smear and PCR analyses and maintained in an incubator at 28 °C for moulting. Four hundred eighteen nymphs moulted to adults 14-16 d post collection. Unfed ticks from the shelter grounds comprised 1,500 larvae, 2,100 nymphs, and 85 adults; were sorted according to origin, developmental stage, and sex into 117 pools; and screened by 18S rRNA PCR for Hepatozoon infection. Of 60 adult tick pools examined, 51 were infected with H. canis. The overall maximum likelihood estimate (MLE) of infection rate was calculated as 21.0% (CI 15.80-28.21). Hepatozoon canis was detected in 31 out of 33 female pools (MLE 26.96%, CI 17.64-44.33) and 20 out of 27 male pools (MLE 14.82%, CI 20.15-46.41). Among 42 unfed nymph pools collected from the shelter, 26 were infected with H. canis, and MLE of infection was calculated as 1.9% (CI 1.25-2.77). No H. canis DNA was detected in any of the gDNA pools consisting of larva specimens. Partial sequences of the 18S rRNA gene shared 99-100% similarity with the corresponding H. canis isolates. Our results revealed the transstadial transmission of H. canis by R. sanguineus, both from larva to nymph and from nymph to adult, in field conditions. However, there were no evidence of transovarial transmission. © 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.

Post-embryonic development of Camallanus cotti (Nematoda: Camallanidae), with emphasis on growth of some taxonomically important somatic characters.

Science.gov (United States)

Levsen, Arne; Berland, Bjørn

2002-01-01

In this paper, the quantitative post-embryonic development of the Asian freshwater fish nematode Camallanus cotti Fujita, 1927, is described. Larval and adult morphometrics were obtained by following the parasite's life cycle experimentally using copepods Macrocyclops albidus (Jurine) as intermediate host and guppies Poecilia reticulata (Peters), southern platyfish Xiphophorus maculatus (Günther) and paradise fish Macropodus opercularis (L.) as definitive host. Additionally, adult worms were obtained from heavily infected paradise fish imported from Singapore. It is suggested that the gradual change in proportions of the worm's somatic body parts reflects the specific ecological role of each developmental stage. The free-living infective first-stage larva seems to be adapted for transmission, as indicated by its relatively long tail, designed to generate host-attracting movements, and its non-functional intestine. The second- and third-stage larvae from the copepod intermediate host seem mainly to invest in trophic functionality, i.e., the development of the buccal capsule and the oesophagus, which are crucial structures for the worm's successful establishment in the definitive fish host. Once in the fish intestine, the larvae enter a period of considerable growth. After the fourth (i.e., last) moult, a 72% increase in average female body length occurs. This is accompanied by doubling the average vulva-tail tip distance and the average tail length. The length of the female hind body expands in an accelerating allometric fashion, and seems to be closely linked to the posterior-wards expansion of the uterus. In the males however, growth seems to cease after the final moult. We conclude that female post-maturational body size, but especially the length of the hind body and the tail, are closely related to reproductive state, i.e., the developmental stage of the offspring in the uterus, and, probably, the worms' age. Any future taxonomical studies of camallanids in

Life-stage-specific differences in exploitation of food mixtures: diet mixing enhances copepod egg production but not juvenile development

DEFF Research Database (Denmark)

Koski, Marja; Breteler, W.K.; Schogt, N.

2006-01-01

, the copepods failed to moult past the first copepodite stage, and the mortality was high. In sharp contrast, mixing two nutritionally poor food species often resulted in egg production which was not significantly different from nutritionally high quality food, although hatching success in many mixtures was low......Development, egg production and hatching success of the calanoid copepods Temora longicornis and Pseudocalanus elongatus were measured in food mixtures to test their ability to obtain a complete nutrition by combining different nutritionally poor food species. In all the food mixtures used....... Whereas egg production was significantly correlated with particulate organic nitrogen in the diet, and independent of the highly unsaturated fatty acids (HUFAs), eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), hatching increased with increasing DHA and EPA concentration. Growth and juvenile...

Effects of anisakid nematodes Anisakis simplex (s.l.), Pseudoterranova decipiens (s.l.) and Contracaecum osculatum (s.l.) on fish and consumer Health

DEFF Research Database (Denmark)

Buchmann, Kurt; Mehrdana, Foojan

2016-01-01

– including euphausiids, copepods and amphipods – feed on these larvae, become infected and serve as intermediate hosts. A range of fish species may serve as transport hosts following ingestion of infected invertebrates and the final stage develops after two additional moults in the stomach of marine mammals......The anisakid nematodes Anisakis simplex (Rudolphi, 1809), Pseudoterranova decipiens (Krabbe, 1878) and Contracaecum osculatum (Rudolphi, 1802) occur as third-stage larvae in marine fish products and may infect consumers ingesting raw or under-cooked fish products. Clinical symptoms associated...... with the infection, termed anisakidosis, vary from irritation of the oesophagus and stomach, via nausea, vomiting and diarrhoea to severe epigastric and abdominal pain. Third-stage larvae of A. simplex are found in the body cavity, musculature and various organs, P. decipiens occur mainly in the fish musculature...

Natural infection rates and transmission of Theileria annulata by Hyalomma anatolicum anatolicum ticks in the Sudan

Directory of Open Access Journals (Sweden)

D.A. Salih

2005-09-01

Full Text Available Hyalomma anatolicum anatolicum nymphs were collected from two localities in the Sudan: Eddamer in Northern Sudan and Wad-Medani in Central Sudan. They were allowed to moult to adult ticks, which were assessed for Theileria infection in their salivary glands using Feulgen stain. At Eddamer, 49.6 % of 123 ticks examined were infected with Theileria and the mean intensity of infection was 1.3 (i.e. the number of infected acini / number of infected ticks. At Wad-Medani, 8.6 % of 162 ticks were infected and the mean intensity of infection was 7.9. The prevalence of infection was higher in female than in male ticks at both localities. When adult H. a. anatolicum were applied onto two susceptible calves, both animals developed the severe form of theileriosis.

Can ant-eating Zodarion spiders (Araneae: Zodariidae) develop on a diet optimal for euryphagous arthropod predators?

DEFF Research Database (Denmark)

Pekar, Stano; Toft, Søren

2009-01-01

. Such adaptations may then entail trade-offs in handling and utilization of alternative prey. To investigate behavioural as well as nutritional adaptations and the occurrence of the corresponding trade-offs in two ant-eating spiders of the genus Zodarion [Zodarion atlanticum Pekár & Cardoso and Zodarion germanicum...... (C. L. Koch)], spiders are reared on two diets: ants (i.e. their preferred prey) and fruit flies (i.e. an alternative prey that is nutritionally optimal for euryphagous spiders). Food consumption is observed and several fitness-related life-history parameters are measured. Although spiders readily...... accept ants, more than one-third of 35 spiders refuse to consume fruit flies and starve. Furthermore, severe hunger does not induce these individuals to accept fruit flies. Starving spiders die before moulting to the second stadium. Spiders that eat fruit flies increase only little and slowly in weight...

Influence of mating on ovarian follicle development in Triatoma infestans (Klug, 1834

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S. Asin

1992-09-01

Full Text Available This works examines the influence of mating on ovarian follicle development in Triatoma infestans. The observations were carried out on both virgin and mated females, wich were killed at various times after their emergence. There was no difference in the ovarian development of both experimental groups during the first gonadotrofic cycle. By the 7th day mated females as well as virgn females showed vitellogenic oocytes. The coriogenesis and ovulation process began on the 13th day after imaginal moulting. However we could observe that egg-laying was dependent on mating. Mated females laid eggs whereas virgin females did not lay eggs. However ovarian production was significantly greater in the mated females. It is suggested that in T. infestans mating stimulates egg-laying but it does not influence the oogenesis and ovulation process.

Biological effects

International Nuclear Information System (INIS)

Trott, K.R.

1973-01-01

Following an introduction into the field of cellular radiation effect considering the most important experimental results, the biological significance of the colony formation ability is brought out. The inactivation concept of stem cells does not only prove to be good, according to the present results, in the interpretation of the pathogenesis of acute radiation effects on moult tissue, it also enables chronicle radiation injuries to be interpreted through changes in the fibrous part of the organs. Radiation therapy of tumours can also be explained to a large extent by the radiation effect on the unlimited reproductiveness of tumour cells. The more or less similar dose effect curves for healthy and tumour tissue in practice lead to intermittent irradiation. The dependence of the intermittent doses and intervals on factors such as Elkind recovery, synchronisation, redistribution, reoxygenation, repopulation and regeneration are reviewed. (ORU/LH) [de

Undersøgelse af Vandrefalken i Sydgrønland

DEFF Research Database (Denmark)

Falk, Knud; Møller, Søren

2007-01-01

This report presents results from the 25th field season of the project "Investigations of the Peregrine Falcon in South Greenland". Following analyses of data from the first 22 years, the primary objectives of the study since 2005 has shifted towards monitoring of a fixed sample of nesting sites ...... collected in 8 nests, and moulted feathers from the adults collected at 7 nests. Among 9 nests, the first egg hatched between 24 June and 13 July (mean 1st July) - a little earlier than the average (4 July) for 1981-2007).......This report presents results from the 25th field season of the project "Investigations of the Peregrine Falcon in South Greenland". Following analyses of data from the first 22 years, the primary objectives of the study since 2005 has shifted towards monitoring of a fixed sample of nesting sites...

Undersøgelse af Vandrefalken i Sydgrønland

DEFF Research Database (Denmark)

Falk, Knud; Møller, Søren

2006-01-01

This report presents results from the 24th field season of the project "Investigations of the Peregrine Falcon in South Greenland". Following analyses of data from the first 22 years, the primary objectives of the study since 2005 has shifted towards monitoring of a fixed sample of nesting sites ...... hatched eggs collected in 8 nests, and moulted feathers from the adults collected at 4 nests. Among 8 nests, the first egg hatched between 25 June and 4 July (mean 28th June) - an early year (average 2 July for 1981-2006).......This report presents results from the 24th field season of the project "Investigations of the Peregrine Falcon in South Greenland". Following analyses of data from the first 22 years, the primary objectives of the study since 2005 has shifted towards monitoring of a fixed sample of nesting sites...

Long-term decreases of corticosterone in captive migrant shorebirds that maintain seasonal mass and moult cycles

NARCIS (Netherlands)

Piersma, T; Ramenofsky, M

Two flocks of Red Knots Calidris canutus, belonging to the temperate-wintering subspecies islandica and to the tropical-wintering subspecies canutus, were kept in outdoor cages at north-temperate latitudes over two annual cycles during which their plasma concentrations of corticosterone were

Moulting and wintering grounds of Marsh Warblers Acrocephalus palustris: evidence from stable isotopes and ring recoveries

Czech Academy of Sciences Publication Activity Database

Procházka, Petr; Kralj, J.; Pearson, D. J.; Yohannes, E.

2014-01-01

Roč. 49, č. 2 (2014), s. 193-200 ISSN 0001-6454 R&D Projects: GA ČR GA13-06451S Institutional support: RVO:68081766 Keywords : bird migration * feather stable isotopes * ring recoveries * stopover * migratory connectivity * δ13C * δ15N Subject RIV: EG - Zoology Impact factor: 0.745, year: 2014

The conserved nuclear receptor Ftz-F1 is required for embryogenesis, moulting and reproduction in Caenorhabditiselegans

Czech Academy of Sciences Publication Activity Database

Asahina, M.; Ishihara, T.; Jindra, Marek; Kohara, Y.; Katsura, I.; Hirose, S.

2000-01-01

Roč. 5, - (2000), s. 711-723 ISSN 1356-9597 R&D Projects: GA ČR GA204/00/0811; GA AV ČR KSK2005601 Institutional research plan: CEZ:AV0Z5007907 Subject RIV: EB - Genetics ; Molecular Biology Impact factor: 4.885, year: 2000

Effect of eyestalk ablation on moulting and growth in the penaeid shrimp Metapenaeus monoceros (Fabricius, 1798)

Digital Repository Service at National Institute of Oceanography (India)

Venkitaraman, P.R.; Jayalakshmy, K.V.; Balasubramanian, T.

of eyestalk excision on the energy budget of juveniles of the Malaycian prawn, Macrobrachium rosenbergii was attempted by Perez and Luna, (1995). Materials and methods Collection of prawns Metapenaeus monoceros was collected from Cochin... siphon system for the cultivation maintenance and management of marine/ estuarine organisms under controlled/ simulated conditions. CSIR patent No. 829. Perez Cruz, M.E. and Luna Figueroa, J. 1995. Effect of the unilateral ablation of the eyestalk...

Additive effect of calcium depletion and low resource quality on Gammarus fossarum (Crustacea, Amphipoda) life history traits.

Science.gov (United States)

Rollin, Marc; Coulaud, Romain; Danger, Michael; Sohm, Bénédicte; Flayac, Justine; Bec, Alexandre; Chaumot, Arnaud; Geffard, Olivier; Felten, Vincent

2018-04-01

Gammarus fossarum is an often-abundant crustacean detritivore that contributes importantly to leaf litter breakdown in oligotrophic, mainly heterotrophic, headwater streams. This species requires large amounts of Ca to moult, thus allowing growth and reproduction. Because resource quality is tightly coupled to the organism's growth and physiological status, we hypothesised that low Ca concentration [Ca] and low food resource quality (low phosphorus [P] and/or reduced highly unsaturated fatty acid [HUFA] contents) would interactively impair molecular responses (gene expression) and reproduction of G. fossarum. To investigate the effects of food resources quality, we experimentally manipulated the P content of sycamore leaves and also used diatoms because they contain high amounts of HUFAs. Three resource quality treatments were tested: low quality (LQ, unmanipulated leaves: low P content), high quality 1 (HQ1; P-manipulated leaves: high P content), and high quality 2 (unmanipulated leaves supplemented with a pellet containing diatoms: high P and HUFA content). Naturally, demineralised stream water was supplemented with CaSO 4 to obtain three Ca concentrations (2, 3.5, and 10.5 mg Ca L -1 ). For 21 days, pairs of G. fossarum were individually exposed to one of the nine treatments (3 [Ca] × 3 resource qualities). At the individual level, strong and significant delays in moult stage were observed in gammarids exposed to lower [Ca] and to lower resource quality, with additive effects lengthening the duration of the reproductive cycle. Effects at the molecular level were investigated by measuring expression of 12 genes involved in energy production, translation, or Ca or P homeostasis. Expression of ATP synthase beta (higher in HQ2), calcified cuticle protein (higher in HQ1 and HQ2), and tropomyosin (higher in HQ2 compared to HQ1) was significantly affected by resource quality, and significant additive effects on Ca transporting ATPase expression were induced by

BUDI DAYA TERPADU Cherax quadricarinatus DAN C. albertisi DENGAN PADI DALAM KOLAM TANAH

Directory of Open Access Journals (Sweden)

Taufik Ahmad

2016-11-01

Cherax spp. in Indonesia is not so well known compare to other crustaceans such as penaeids shrimp, the main aquaculture products. Since the 1990’s, the production of cherax post larvae has been intended to supply the hobbyists of ornamental crustaceans.  No data available of how large is the production of cherax in Indonesia, either for food or ornament. To provide evidence that cherax is not a padi eater, an experiment was carried out in an integrated culture with padi in 1 m x 1 m x 0.5 m earthen ponds. The cherax stocked into the ponds are C. quadricarinatus and C. albertisi, at 15 PL-45/m2 of each different pond. The water depth in each pond is maintained at 30—40 cm on the perimeter ditch. The feed, grower penaeids shrimp feed, is given at 3% biomass weight when necessary. The cherax is sampled every 30 days for total and carapace length as well as individual weight. Number and weight of grain produced and numbers of paddy seedling are the variable observed to monitor padi growth. The number of grains and seedling in cherax ponds which is not significantly different (P>0.05 from those in ponds without cherax indicating that cherax is not padi eater. Either C. quadricarinatus or C. albertisi achieved maximum individual weight of 20 g in 90 days rearing period. Both of the cherax are dyke hole maker, but tend to causing seepage. The depth of the hole ranges from 20—80 cm, just enough for the cherax to hide just after moulting. Obviously, cherax culture could be developed as a new source of income for the farmers and would not cherax is not padi eater. Either C. quadricarinatus or C. albertisi achieved maximum individual weight of 20 g in 90 days rearing period. Both of the cherax are dyke hole maker, but tend to causing seepage. The depth of the hole ranges from 20—80 cm, just enough for the cherax to hide just after moulting. Obviously, cherax culture could be developed as a new source of income for the farmers and would not threaten the production

Impact Assessment of an Off-Shore Wind Park on Sea Ducks

DEFF Research Database (Denmark)

Guillemette, M.; Larsen, J. K.; Clausager, I.

of the study with a marked difference between Tunø Knob and Ringebjerg Sand in the size available. This was associated with a general impoverishment of the whole benthic community. This suggests that the decrease observed in sea duck abundance over the three years was caused by the availability of food supply......As part of the plan of the Danish government to expand off-shore wind energy production, The Ministry of Environment and Energy, in collaboration with ELSAM (an energy consortium), initiated a three-year study of the potential conflict between the Tunø Knob off-shore wind park and aquatic birds...... in 1994-97. Danish coastal waters support very large, internationally important concentrations of moulting, migrating and wintering sea ducks which depend on shallow water areas as major feeding habitats. Denmark is committed, in relation to international conventions and EU directives, to protect...

Comparative Immature Morphology of Brazilian Fire Ants (Hymenoptera: Formicidae: Solenopsis

Directory of Open Access Journals (Sweden)

Eduardo Gonçalves Paterson Fox

2012-01-01

Full Text Available Although common in Brazil, the biology of the fire ant Solenopsis saevissima (Smith is still poorly studied. Larval descriptions are useful to genus-level ant systematics and sometimes to species-level taxonomy. This study presents a detailed description of juveniles of S. saevissima from Brazil, which were compared with Brazilian specimens of Solenopsis invicta Buren, Solenopsis geminata (Fabricius, and Solenopsis altipunctata Pitts. Different larval instars were separated by diagnostic morphological traits which were confirmed by observing moults. Reproductive larvae could be easily sorted by their distinctive body dimensions and shape. Contrary to previous reports on this species, the larvae of S. saevissima proved to be generally identical to those of S. invicta, while a few specimens resembled those of other close species, such as Solenopsis megergates Trager. Mature larvae thus presented considerable intraspecific variation in some characters recently proposed to aid fire ant species separation (morphology of head hairs.

Properties of 5-aminolaevulinate synthetase and its relationship to microsomal mixed-function oxidation in the southern armyworm (Spodoptera eridania).

Science.gov (United States)

Brattsten, L B; Wilkinson, C F

1975-07-01

1. Activity of 5-aminolaevulinate synthetase was measured in the midgut and other tissues of the last larval instar of the southern armyworm (Spodoptera eridania Cramer, formerly Prodenia eridania Cramer). 2. Optimum conditions for measuring the activity were established with respect to all variables involved and considerable differences from those reported for mammalian enzyme preparations were found. 3. Maximum activity (20 nmol/h per mg of protein) occurs 18-24 h after the fifth moult and thereafter decreases to trace amounts as the larvae age and approach pupation. 4. Synthetase activity was rapidly induced by oral administration (in the diet) of pentamethylbenzene, phenobarbital, diethyl 1,4-dihydro-2,4,6-trimethylpyridine-3, 5-dicarboxylate, and 2-allyl-2-isopropylacetamide. 5. Puromycin inhibited the induction of synthetase by pentamethylbenzene. 6. Induction of 5-aminolaevulinate synthetase correlated well with the induction of microsomal N-demethylation of p-chloro-N-methylaniline, except for phenobarbital, which induced the microsomal oxidase relatively more than the synthetase.

Anaerobic bacteria in the gut of terrestrial isopod Crustacean Porcellio scaber.

Science.gov (United States)

Kostanjsek, R; Lapanje, A; Rupnik, M; Strus, J; Drobne, D; Avgustin, G

2004-01-01

Anaerobic bacteria from Porcellio scaber hindgut were identified and, subsequently, isolated using molecular approach. Phylogenetic affiliation of bacteria associated with the hindgut wall was determined by analysis of bacterial 16S rRNA gene sequences which were retrieved directly from washed hindguts of P. scaber. Sequences from bacteria related to obligate anaerobic bacteria from genera Bacteroides and Enterococcus were retrieved, as well as sequences from 'A1 subcluster' of the wall-less mollicutes. Bacteria from the genus Desulfotomaculum were isolated from gut wall and cultivated under anaerobic conditions. In contrast to previous reports which suggested the absence of anaerobic bacteria in the isopod digestive system due to short retention time of the food in the tube-like hindgut, frequent renewal of the gut cuticle during the moulting process, and unsuccessful attempts to isolate anaerobic bacteria from this environment our results indicate the presence of resident anaerobic bacteria in the gut of P. scaber, in spite of apparently unsuitable, i.e. predominantly oxic, conditions.

Monitoring the numbers and productivity of Tundra Swans in relation to potential natural gas development in the Mackenzie River Delta, western Canadian Arctic, 2001-2003

Energy Technology Data Exchange (ETDEWEB)

Swystun, H.A. [Northern British Columbia Univ., Prince George, BC (Canada); Hines, J.E. [Canadian Wildlife Service, Ottawa, ON (Canada); Dawson, R.D. [Northern British Columbia Univ., Prince George, BC (Canada)

2005-03-01

A study was conducted in which tundra swans were used as an indicator species to monitor the environmental change and effects of oil and gas development in the Mackenzie Delta. The objectives were to monitor consistent study plots for tundra swans at development and non development sites and to document nesting success and brood survival. Environmental protection and maintenance of harvestable populations of wildlife are part of land claim agreement for two Aboriginal groups with settled land claims in the Mackenzie Delta. This study also evaluated the possible factors such as habitat and climate, which limit the reproductive success of tundra swans. Their nesting biology was examined along with how they use their habitat. Researchers established 48 plots near exploratory well sites, existing camps, sites of recent seismic exploration and gas fields of known importance. Air surveillance was used to count and observe the swans on a yearly basis, along with their nests and offspring. Plots were located both where development is proposed and where development is not likely to occur. The important spring staging, summer moulting and fall staging areas were identified along with spring migration patterns, behaviour and feeding areas. The 3 proposed drilling sites include Niglingtak (Kendall Island Bird Sanctuary), Taglu, and Parsons Lake. The concerns regarding future development in tundra swan habitat include: (1) areas where drilling and pipeline structures are built may prompt swans to move away from their traditional nesting and feeding areas, (2) human activity will increase due to gas drilling and pipeline construction, which may reduce nesting success, (3) wastes associated with construction sites may attract predators and increase predation on nesting birds, (4) increased air traffic would disturb geese and swan hunting areas, and (5) waterfowl habitat could be lost if spring staging, summer moulting and fall staging areas are not considered when planning

APLIKASI INSEMINASI BUATAN PADA UDANG WINDU, Penaeus monodon ALAM MENGGUNAKAN SUMBER DAN JUMLAH SPERMATOFOR YANG BERBEDA

Directory of Open Access Journals (Sweden)

Samuel Lante

2017-01-01

Full Text Available Salah satu kendala utama dalam domestikasi udang windu adalah rendahnya tingkat perkawinan secara alami dalam wadah budidaya. Hal yang sama terjadi pada udang windu alam yang digunakan di unit pembenihan. Salah satu upaya untuk mendapatkan telur fertil adalah melalui inseminasi buatan (IB. Inseminasi buatan merupakan teknik mentransfer spermatofor dari induk jantan dengan cara memasukkannya ke dalam telikum udang betina. Penelitian ini bertujuan untuk mengetahui performa reproduksi udang windu betina alam pasca-inseminasi menggunakan sumber dan jumlah spermatofor induk jantan alam yang berbeda. Penelitian dilakukan dua tahap yaitu 1 IB menggunakan spermatofor induk jantan dari perairan Sulawesi Selatan (SS dan spermatofor induk jantan dari Aceh (SA dan 2 IB menggunakan jumlah spermatofor berbeda yaitu satu spermatofor (S-1 dan dua spermatofor (S-2 pada udang windu betina alam. Inseminasi spermatofor dilakukan pada induk udang windu betina setelah dua hari moulting. Hasil yang diperoleh pada IB tahap pertama menunjukkan bahwa daya tetas telur udang windu betina alam lokal tidak dipengaruhi oleh sumber (lokasi asal udang jantan, di mana daya tetas telur relatif sama pada kedua perlakuan, yaitu 61,6% pada SS dan 61,7% pada SA. IB pada tahap kedua menunjukkan bahwa daya tetas telur fertil yang diperoleh pada S-2 sebesar 40,5%; lebih rendah dari S-1 sebesar 44%. One of the main constraints in the domestication of black tiger shrimp is very low natural mating in the tank. Similar condition have been happened in commercial hatcheries. An effort to improve the eggs fertility is through artificial insemination (AI. This study aimed to know reproductive performance of wild black tiger shrimp after insemination with different sources and numbers of spermatophore. This study consisted of two trials.The first one was AI using spermatophores of wild male obtained from two different locations, namely from South Sulawesi (SS and Aceh (SA. The second trial was

Post-embrionic development of the digestive tube of Dermatobia hominis (Linnaeus (Diptera, Cuterebridae

Directory of Open Access Journals (Sweden)

Ana Maria Vieira

1996-01-01

Full Text Available The digestive tube of 2nd and 3rd instar larvae, pupae and newly emerged adults of Dermatobia hominis (Linnaeus, 1781 was studied anatomically. The specimens were dissected in buffer saline under a stereomicroscope, and the digestive tubes were placed on slides and fixed in 10% buffered formalin. Each tube was measured using a micrometric eye piece, and drawings were made with camera lucida. The results showed that the midgut, the hindgut and the Malpighian tubules with their ducts grow gradually during the larval development. The oesophagus and the salivary glands with their ducts grow only during the moult from the 2nd to the 3rd instar. In the pupal period, salivary glands grow gradually but disappeared after the 20th day. After metamorphosis the digestive tube regressed. This is expected since adult D. hominis lives about nine days without feeding. This fly, similar to other calyptratae muscoid flies shows no vestige of a crop during all post-embrionic development, and the adult has no salivary glands.

Revealing the diversity of a once small taxon: the genus Selenoribates (Acari, Oribatida, Selenoribatidae

Directory of Open Access Journals (Sweden)

Tobias Pfingstl

2013-06-01

Full Text Available Three new intertidal oribatid species, Selenoribates elegans sp. n., Selenoribates quasimodo sp. n. and Selenoribates satanicus sp. n. are described from the archipelago of Bermuda. Selenoribates elegans sp. n. is characterized by its slender body shape, S. quasimodo sp. n. possesses a hunchback in lateral view and S. satanicus sp. n. exhibits two horn-like projections on its anterior gastronotic region. Based on these new findings, the number of Selenoribates species doubled at once and the distribution of this genus, formerly limited to the Mediterranean and the Red Sea, includes now occurrences in the Atlantic and Indo-pacific Ocean as well. The morphology of S. quasimodo sp. n. and S. satanicus sp. n. deviates conspicuously from the other known members of Selenoribates, thus indicating that not only the number of species but also the anatomy of this genus is more diverse than formerly supposed. Nymphs of S. quasimodo sp. n. show an interesting case of ontogenetic neotrichy, with gastronotic setae being duplicated with each moult.

Persistent organic pollutants (POPs) in Caspian seals of unusual mortality event during 2000 and 2001

International Nuclear Information System (INIS)

Kajiwara, Natsuko; Watanabe, Mafumi; Wilson, Susan; Eybatov, Tariel; Mitrofanov, Igor V.; Aubrey, David G.; Khuraskin, Lev S.; Miyazaki, Nobuyuki; Tanabe, Shinsuke

2008-01-01

Persistent organic pollutants including organochlorine pesticides, PCBs, and PCDDs/DFs were determined in the blubber of Caspian seals, which died during an outbreak of canine distemper virus in 2000 and 2001. DDTs were the predominant contaminants that ranged from 3.1 to 560 μg/g lipid. A negative correlation was observed between concentration of contaminants and blubber thickness. During spring, as the blubber layer becomes thin after breeding and moulting, seals may face higher risk due to the increased concentration of organochlorines in their bodies. TEQs in the blubber of Caspian seals (10-340 pg TEQ/g) were lower than those in seals from other locations, suggesting that toxic effects of these contaminants are a deal less in the present population and they are unlikely to be linked to mass mortality. The levels of PCBs and pesticides in Caspian seals, however, comparable to those in other aquatic mammals that have suffered from epizootics, might pose a risk of immunosuppression. - POPs in seals are high enough to induce immunosuppression

Persistent organic pollutants (POPs) in Caspian seals of unusual mortality event during 2000 and 2001

Energy Technology Data Exchange (ETDEWEB)

Kajiwara, Natsuko [Center for Marine Environmental Studies, Ehime University, 2-5 Bunkyo-cho, Matsuyama 790-8577 (Japan)], E-mail: kajiwara.natsuko@nies.go.jp; Watanabe, Mafumi [Center for Marine Environmental Studies, Ehime University, 2-5 Bunkyo-cho, Matsuyama 790-8577 (Japan); Wilson, Susan [Tara Seal Research Centre, Co. Down, Northern Ireland (United Kingdom); Eybatov, Tariel [Geological Institute of the Azerbaijan Republic Academy of Science, Baku (Azerbaijan); Mitrofanov, Igor V. [Laboratory of Hydrobiology and Ecotoxicology, Institution of Zoology, Academgorodok, Almaty 480060 (Kazakhstan); Aubrey, David G. [Woods Hole Oceanographic Institution, Woods Hole, MA 02543 (United States); Khuraskin, Lev S. [Caspian Fisheries Research Institute, Astrakhan 414056 (Russian Federation); Miyazaki, Nobuyuki [Center for International Cooperation, Ocean Research Institute, The University of Tokyo, 1-15-1 Minamidai, Nakano-ku, Tokyo 164-8639 (Japan); Tanabe, Shinsuke [Center for Marine Environmental Studies, Ehime University, 2-5 Bunkyo-cho, Matsuyama 790-8577 (Japan)

2008-03-15

Persistent organic pollutants including organochlorine pesticides, PCBs, and PCDDs/DFs were determined in the blubber of Caspian seals, which died during an outbreak of canine distemper virus in 2000 and 2001. DDTs were the predominant contaminants that ranged from 3.1 to 560 {mu}g/g lipid. A negative correlation was observed between concentration of contaminants and blubber thickness. During spring, as the blubber layer becomes thin after breeding and moulting, seals may face higher risk due to the increased concentration of organochlorines in their bodies. TEQs in the blubber of Caspian seals (10-340 pg TEQ/g) were lower than those in seals from other locations, suggesting that toxic effects of these contaminants are a deal less in the present population and they are unlikely to be linked to mass mortality. The levels of PCBs and pesticides in Caspian seals, however, comparable to those in other aquatic mammals that have suffered from epizootics, might pose a risk of immunosuppression. - POPs in seals are high enough to induce immunosuppression.

Element patterns in albatrosses and petrels: Influence of trophic position, foraging range, and prey type

International Nuclear Information System (INIS)

Anderson, O.R.J.; Phillips, R.A.; Shore, R.F.; McGill, R.A.R.; McDonald, R.A.; Bearhop, S.

2010-01-01

We investigated the concentrations of 22 essential and non-essential elements among a community of Procellariiformes (and their prey) to identify the extent to which trophic position and foraging range governed element accumulation. Stable isotope analysis (SIA) was used to characterise trophic (δ 15 N) and spatial patterns (δ 13 C) among species. Few consistent patterns were observed in element distributions among species and diet appeared to be highly influential in some instances. Arsenic levels in seabird red blood cells correlated with δ 15 N and δ 13 C, demonstrating the importance of trophic position and foraging range for arsenic distribution. Arsenic concentrations in prey varied significantly across taxa, and in the strength of association with δ 15 N values (trophic level). In most instances, element patterns in Procellariiformes showed the clearest separation among species, indicating that a combination of prey selection and other complex species-specific characteristics (e.g. moult patterns) were generally more important determining factors than trophic level per se. - Trophic position, foraging range, and prey type were found to influence element compositions and concentrations in Procellariiformes from South Georgia.

Hallucigenia's head and the pharyngeal armature of early ecdysozoans.

Science.gov (United States)

Smith, Martin R; Caron, Jean-Bernard

2015-07-02

The molecularly defined clade Ecdysozoa comprises the panarthropods (Euarthropoda, Onychophora and Tardigrada) and the cycloneuralian worms (Nematoda, Nematomorpha, Priapulida, Loricifera and Kinorhyncha). These disparate phyla are united by their means of moulting, but otherwise share few morphological characters--none of which has a meaningful fossilization potential. As such, the early evolutionary history of the group as a whole is largely uncharted. Here we redescribe the 508-million-year-old stem-group onychophoran Hallucigenia sparsa from the mid-Cambrian Burgess Shale. We document an elongate head with a pair of simple eyes, a terminal buccal chamber containing a radial array of sclerotized elements, and a differentiated foregut that is lined with acicular teeth. The radial elements and pharyngeal teeth resemble the sclerotized circumoral elements and pharyngeal teeth expressed in tardigrades, stem-group euarthropods and cycloneuralian worms. Phylogenetic results indicate that equivalent structures characterized the ancestral panarthropod and, seemingly, the ancestral ecdysozoan, demonstrating the deep homology of panarthropod and cycloneuralian mouthparts, and providing an anatomical synapomorphy for the ecdysozoan supergroup.

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.

Étude de la toxicité des extraits foliaires d’Euphorbia guyoniana Boiss. et Reut. (Euphorbiaceae chez Schistocerca gregaria (Forskål, 1775 (Orthoptera-Acrididea

Directory of Open Access Journals (Sweden)

A. KEMASSI

2013-03-01

Full Text Available Study of the toxicity of the crude acetone leaf extract of Euphorbia guyoniana Boiss. and Reut. (Euphorbiaceae in Schistocerca gregaria (Forskål, 1775 (Orthoptera-Acrididea Abstract-This study examines the effect by ingestion of leaf cabbage sprayed with crude acetone extract of Euphorbia guyoniana leaves harvested in the Algerian Sahara on some biological parameters of larvae L5 and adult of desert locusts. The ingestion of cabbage leaves soaked in acetone extract of this Saharan plant generates a 100% mortality in larvae L5 and 66,67% for adult. A significant reduction in food intake was observed in the treated population compared to the control population. It results in a loss of exceptional weight ranging from 26,93% in larvae L5 to 33,09% in adults. Difficulties and anomalies are observed in moulting 16,66% of larvae L5 fed with cabbage leaves soaked in leaf extract of E. guyoniana. Dissection of adult females of the lot processing allows the observation of body regression demonstrating the depressant action of this extract on ovocyte cycle in the desert locust.

Experimental studies on californium bioavailability to marine benthic invertebrates

International Nuclear Information System (INIS)

Fowler, S.W.; Carvalho, F.P.; Aston, S.R.

1986-01-01

252 Cf is readily taken up by benthic invertebrates from sea water, reaching whole-body concentration factors of 763 in the polychaete Hermione hystrix, 220 in the shrimp Lysmata seticaudata, 665 in the crab Pilumnus hirtellus and 78 in the bivalve mollusc Venerupis decussata after 3 weeks exposure. Surface sorption plays a predominant role in the uptake process. Depuration in clean sea water was a relatively slow process. The shrimp Lysmata eliminated 252 Cf very rapidly due to moulting. Absorption coefficients for ingested 252 Cf were high, approx. 23% in crabs and approx. 97% in brittlestars. The absorbed fraction was excreted twice as fast from crabs as brittlestars. Exposure of organisms to labelled sediment resulted in low transfer factors that were species dependent. There is some evidence to suggest that uptake from sediments is primarily due to 252 Cf transfer from the pore water. Comparison of these results with published experimental data on other transuranic nuclides in the same or similar species suggests that californium bioavailability is roughly equivalent to that of plutonium and americium. (author)

House-dust mites in our homes are a contamination from outdoor sources.

Science.gov (United States)

Hallas, Thorkil E

2010-05-01

Avoidance advices for house-dust mite sensitized persons are currently based upon the idea, that the mites (Dermatophagoides spp.) are part of the indoor fauna. A closer look at development stages in the house-dust samples shows, however, that only the mites' active stages are present there and that the stages between them, the inactive moulting stages, are absent. Therefore the mites probably do not carry out their life cycles in our dwellings, but are more likely contaminations from the open. Findings of low level concentrations can be explained by mites coming from outdoors and sedimented in accordance with known physical laws. The occasional finding of higher concentrations is the result of synchronized populations of the mites developing outdoors and being passively transported into our homes by wind and dust. The hypothesis explains why we find mites in our homes but nonetheless have no effect of avoidance measures. The verification of the entire hypothesis or part of it may have great impact on the management of the disease house-dust mite allergy.

Undersøgelse af Vandrefalken i Sydgrønland

DEFF Research Database (Denmark)

Falk, Knud; Møller, Søren

This report presents results from the 27th field season of the project "Investigations of the Peregrine Falcon in South Greenland". Following analyses of data from the first 22 years, the primary objectives of the study since 2005 has shifted towards monitoring of a fixed sample of nesting sites ...... feathers from the adults collected at 7 nests. Among 8 nests, the first egg hatched between 27 June and 20 July (mean 7 July) - a little later than the average (4 July) for 1981-2009).......This report presents results from the 27th field season of the project "Investigations of the Peregrine Falcon in South Greenland". Following analyses of data from the first 22 years, the primary objectives of the study since 2005 has shifted towards monitoring of a fixed sample of nesting sites...... where reproduction, timing of breeding and monitoring of loads and effects of contaminants are carried out annually. Twelve sites have been selected, and in 2009 they produced 2.9 young/successful site and 1.9 young/occupied territory. Fragments from hatched eggs collected in 8 nests, and moulted...

Life cycle and morphology of a cambrian stem-lineage loriciferan.

Science.gov (United States)

Peel, John S; Stein, Martin; Kristensen, Reinhardt Møbjerg

2013-01-01

Cycloneuralians form a rich and diverse element within Cambrian assemblages of exceptionally preserved fossils. Most resemble priapulid worms whereas other Cycloneuralia (Nematoda, Nematomorpha, Kinorhyncha, Loricifera), well known at the present day, have little or no fossil record. First reports of Sirilorica Peel, 2010 from the lower Cambrian Sirius Passet fauna of North Greenland described a tubular lorica covering the abdomen and part of a well developed introvert with a circlet of 6 grasping denticles near the lorica. The introvert is now known to terminate in a narrow mouth tube, while a conical anal field is also developed. Broad muscular bands between the plates in the lorica indicate that it was capable of movement by rhythmic expansion and contraction of the lorica. Sirilorica is regarded as a macrobenthic member of the stem-lineage of the miniaturised, interstitial, present day Loricifera. Like loriciferans, Sirilorica is now known to have grown by moulting. Evidence of the life cycle of Sirilorica is described, including a large post-larval stage and probably an initial larva similar to that of the middle Cambrian fossil Orstenoloricusshergoldii.

Life cycle and morphology of a cambrian stem-lineage loriciferan.

Directory of Open Access Journals (Sweden)

John S Peel

Full Text Available Cycloneuralians form a rich and diverse element within Cambrian assemblages of exceptionally preserved fossils. Most resemble priapulid worms whereas other Cycloneuralia (Nematoda, Nematomorpha, Kinorhyncha, Loricifera, well known at the present day, have little or no fossil record. First reports of Sirilorica Peel, 2010 from the lower Cambrian Sirius Passet fauna of North Greenland described a tubular lorica covering the abdomen and part of a well developed introvert with a circlet of 6 grasping denticles near the lorica. The introvert is now known to terminate in a narrow mouth tube, while a conical anal field is also developed. Broad muscular bands between the plates in the lorica indicate that it was capable of movement by rhythmic expansion and contraction of the lorica. Sirilorica is regarded as a macrobenthic member of the stem-lineage of the miniaturised, interstitial, present day Loricifera. Like loriciferans, Sirilorica is now known to have grown by moulting. Evidence of the life cycle of Sirilorica is described, including a large post-larval stage and probably an initial larva similar to that of the middle Cambrian fossil Orstenoloricusshergoldii.

Developmental and moult cycle related biochemical changes in larvae of the spider crab, Maja brachydactyla (Brachyura: Majidae)

OpenAIRE

Guiomar Rotllant; Guillermo Guerao; Marta Sastre; Klaus Anger

2012-01-01

Se han estudiado los cambios ontogénicos en peso seco, composición elemental (CHN), y actividad enzimática (proteasas totales, amilasas) durante el ciclo de muda en todos los estadios larvarios (zoea I-II, megalopa; ZI, ZII, M) del centollo Maja brachydactyla Balss, 1922 cultivados en el laboratorio. Se ha observado un incremento gradual y significativo en la biomasa durante los estadios de zoea, seguido de un crecimiento brusco en la megalopa alcanzando valores máximos en el estado de muda D...

Fuelling and moult in Red Knots before northward departure: a visual evaluation of differences between ages, sexes and subspecies

NARCIS (Netherlands)

Verhoeven, M.A.; Van Eerbeek, J.; Hassell, C.J.; Piersma, T.

2016-01-01

The departure of migratory birds from their non-breeding grounds is thought to be driven by the phenologyof their breeding destination. In north-west Australia, two plumage morphs of Red Knot (Calidris canutus) prepare for a5500-km journey to Yellow Sea staging areas. These morphs are recognised as

Variation in carbon and nitrogen stable isotope ratios in flight feathers of a moulting White-bellied Sunbird Cinnyris talatala

CSIR Research Space (South Africa)

Symes, CT

2011-11-01

Full Text Available The authors measured d13C and d15N isotope signatures in flight feathers of a White-bellied Sunbird to assess the value of using stable isotopes of feathers in avian dietary studies. Significant variation in d13C and d15N isotope values of flight...

Effects of different feeding levels on moulting, growth, food conversion efficiency and biochemical composition of the prawn, metapenaeus monoceros (Fabricius)

Digital Repository Service at National Institute of Oceanography (India)

Sumitra-Vijayaraghavan; Royan, J.P.; Rao, T.S.S.

food/g prawn/day represented the maintenance, optimum and maximum feeding levels Specific dynamic action increased twice at the observed maximum feeding level (20%) than at optimum feeding level (12%), indicating that the energy cost of converting food...

Uptake and effects of americium-241 on a brackish-water amphipod

Energy Technology Data Exchange (ETDEWEB)

Hoppenheit, M.; Murray, C.N.; Woodhead, D.S.

1980-01-01

The present paper reports the results of experimental work undertaken using the brackish-water amphipod Gammarus duebeni duebeni and the transuranium nuclide americium-241. Data on the accumulation of this actinide showed that the larger fraction of the total body burden is associated with the exoskeleton. It was found that the body burden remained constant in the range pH 8.0-6.5 even though the water concentration changed markedly. It would thus appear that the concept of a concentration factor should be re-examined and it is proposed that a factor should be defined in terms of environmental and chemical parameters which represent the bioavailable fraction of the actinide. The effect of americium on survival and moulting was studied at two activity concentrations; the dose rates and absorbed doses under the experimental conditions employed have been estimated. The differences in survival rates between the control and irradiated groups were statistically analyzed and the significant difference at the higher concentration is believed to be due to a synergism between physiological stress and radiotoxicity of americium rather than the chemical toxicity of the element.

Uptake and effects of americium-241 on a brackish-water amphipod

International Nuclear Information System (INIS)

Hoppenheit, M.; Murray, C.N.; Woodhead, D.S.

1980-01-01

The present paper reports the results of experimental work undertaken using the brackish-water amphipod Gammarus duebeni duebeni and the transuranium nuclide americium-241. Data on the accumulation of this actinide showed that the larger fraction of the total body burden is associated with the exoskeleton. It was found that the body burden remained constant in the range pH 8.0-6.5 even though the water concentration changed markedly. It would thus appear that the concept of a concentration factor should be re-examined and it is proposed that a factor should be defined in terms of environmental and chemical parameters which represent the bioavailable fraction of the actinide. The effect of americium on survival and moulting was studied at two activity concentrations; the dose rates and absorbed doses under the experimental conditions employed have been estimated. The differences in survival rates between the control and irradiated groups were statistically analyzed and the significant difference at the higher concentration is believed to be due to a synergism between physiological stress and radiotoxicity of americium rather than the chemical toxicity of the element. (orig.) [de

Do antiparasitic medicines used in aquaculture pose a risk to the Norwegian aquatic environment?

Science.gov (United States)

Langford, Katherine H; Øxnevad, Sigurd; Schøyen, Merete; Thomas, Kevin V

2014-07-15

Aquaculture production is an important industry in many countries and there has been a growth in the use of medicines to ensure the health and cost effectiveness of the industry. This study focused on the inputs of sea lice medication to the marine environment. Diflubenzuron, teflubenzuron, emamectin benzoate, cypermethrin, and deltamethrin were measured in water, sediment, and biota samples in the vicinity of five aquaculture locations along the Norwegian coast. Deltamethrin and cypermethrin were not detected above the limits of detection in any samples. Diflubenzuron, teflubenzuron, and emamectin benzoate were detected, and the data was compared the UK Environmental Quality Standards. The concentrations of emamectin benzoate detected in sediments exceed the environmental quality standard (EQS) on 5 occasions in this study. The EQS for teflubenzuron in sediment was exceeded in 67% of the samples and exceeded for diflubenzuron in 40% of the water samples collected. A crude assessment of the concentrations detected in the shrimp collected from one location and the levels at which chronic effects are seen in shrimp would suggest that there is a potential risk to shrimp. It would also be reasonable to extrapolate this to any species that undergoes moulting during its life cycle.

Traces of an ancient immune system - how an injured arthropod survived 465 million years ago

Science.gov (United States)

Schoenemann, Brigitte; Clarkson, Euan N. K.; Høyberget, Magne

2017-01-01

This report of a severely injured trilobite from the Middle Ordovician (~465 Ma) accords with a number of similar observations of healed lesions observed in trilobites. The uniqueness of the specimen described here is that the character of the repair-mechanisms is reflected by the secondarily built structures, which form the new surface of the ruptured compound eye. Smooth, repaired areas inside the visual surface advert to a clotting principle, rather similar to those of today, and the way in which broken parts of the exoskeleton fused during restoration seem to simulate modern samples. The irregularity and variance of newly inserted visual units indicate the severity of the injury, which, most probably, was caused by a predatory attack, presumably by a cephalopod; these were most likely, the top predators of the Ordovician. Furthermore, the state of the moulted cephalon tells the dramatic struggle of an organism that lived in the Palaeozoic, to survive. In sum the specimen analysed here is evidence of an ancient clotting mechanism not dissimilar to those of today, rapidly preventing any exsanguination and the breakdown of osmoregulation of this marine arthropod.

Anti-proliferative effect of 20-hydroxyecdysone in a lepidopteran cell line.

Science.gov (United States)

Auzoux-Bordenave, Stéphanie; Hatt, Philippe-Jacques; Porcheron, Patrick

2002-02-01

Ecdysteroids are steroid hormones involved in the epidermal growth of arthropods, controlling cell proliferation and further differentiation of target cells. The epidermal cell line IAL-PID2, established from imaginal discs of the Indian meal moth Plodia interpunctella kept its sensitivity to ecdysteroids in vitro, cells being able to respond to them by cytological and biochemical changes. When added to the culture medium, 20-hydroxyecdysone (20E) stopped cell proliferation and induced formation of epithelial-like aggregates. In order to better understand the cellular sequence of ecdysteroids signalling in epidermal cells we used the IAL-PID2 cell line for in vitro investigations of cytological events induced by the moulting hormone. After a 40 h serum deprivation, formazan assay (XTT) was routinely used to evaluate anti-proliferative effects of 20E during cell cycle. We established a more precise timing of the period of cell sensitivity to the hormone during the cell cycle, by the use of the mitotic index and the BrdU incorporation test. These in vitro assays were performed in parallel with the description of some hormone dependant cytological events, using immunofluorescent labelling with anti-beta tubulin/FITC antibodies and DNA staining.

Comparative analysis of the transcriptional responses to low and high temperatures in three rice planthopper species.

Science.gov (United States)

Huang, Hai-Jian; Xue, Jian; Zhuo, Ji-Chong; Cheng, Ruo-Lin; Xu, Hai-Jun; Zhang, Chuan-Xi

2017-05-01

The brown planthopper (Nilaparvata lugens, BPH), white-backed planthopper (Sogatella furcifera, WBPH) and small brown planthopper (Laodelphax striatellus, SBPH) are important rice pests in Asia. These three species differ in thermal tolerance and exhibit quite different migration and overwintering strategies. To understand the underlying mechanisms, we sequenced and compared the transcriptome of the three species under different temperature treatments. We found that metabolism-, exoskeleton- and chemosensory-related genes were modulated. In high temperature (37 °C), heat shock protein (HSP) genes were the most co-regulated; other genes related with fatty acid metabolism, amino acid metabolism and transportation were also differentially expressed. In low temperature (5 °C), the differences in gene expression of the genes for fatty acid synthesis, transport proteins and cytochrome P450 might explain why SBPH can overwinter in high latitudes, while BPH and WBPH cannot. In addition, other genes related with moulting, and membrane lipid composition might also play roles in resistance to low and high temperatures. Our study illustrates the common responses and different tolerance mechanisms of three rice planthoppers in coping with temperature change, and provides a potential strategy for pest management. © 2017 John Wiley & Sons Ltd.

Lethal mutation of internal irradiation brown planthopper (Nilaparvita lugens Stal)

International Nuclear Information System (INIS)

Wahid, R.A.

1988-01-01

The moulting IVth of BPH nympha were irradiated internally with radiophosphorous 32-P 1 uCi/ml, 10 uCi/ml, 50 uCi/ml, 100 uCi/ml, and 500 uCi/ml concentrations respectivelly. An observation was carried out to determines heredity of hopper sterilities from the mating groups of R male x N female, R male x R female, and N male x R female. The 32-P concentration below of 50 uCi/ml seemed to be the substerile dose, however, the dominant lethal mutation has been visually shown by R male x R female F1 mating group. The hereditary lines of F1, F2, F3, and F4 of the hopper sterilities wich were indicated by the nympha hatch ability have some significant correlations (r1= -0.77, r2= -0.92, r3= -0.93 and r4= -0.85). Thus, the resesif lethal mutations visually showed by F3 and F4 from all of the 100 uCi/ml and 50 uCi/ml treated groups. (author). 10 refs, 2 figs, 2 tabs

Rilleyella petauri gen. nov., sp. nov. (Pentastomida : Cephalobaenida from the lungs and nasal sinus of Petaurus breviceps (Marsupialia : Petauridae in Australia

Directory of Open Access Journals (Sweden)

Spratt D.M.

2003-09-01

Full Text Available A new cephalobaenid pentastome, Rileyella petauri gen. nov., sp. nov. from the lungs and nasal sinus of the petaurid marsupial, Petaurus breviceps, is described. It is the smallest adult pentastome known to date, represents the first record of a mammal as the definitive host of a cephalobaenid and may respresent the only pentastome known to inhabit the lungs of a mammal through all its instars, with the exception of patent females. Adult males, non-gravid females and nymphs moulting to adults occur in the lungs; gravid females occur in the nasal sinus. R. petauri is minute and possesses morphological features primarily of the Cephalobaenida but the glands in the cephalothorax and the morphology of the copulatory spicules are similar to some members of the remaining pentastomid order, the Porocephalida. This unusual combination of features distinguish the new genus from other genera in the Cephalobaenida. The occurrence of only seven fully-formed larvae in eggs in the uterus, each representing about 10 % of the length of the patent female, and her presence in the nasal sinus of a dependent juvenile P. breviceps (36 gm implies a direct life cycle.

Overlap in diet and distribution of two goose species suggests potential for competition at a common moulting area in West Greenland

DEFF Research Database (Denmark)

Raundrup, Katrine; Levermann, Nette; Poulsen, Michael

2012-01-01

found, and behavioural observations indicated only slight modifications in attentive behaviour and increased distance to the lakeshore in sympatry. This would seem to imply that the area has sufficient space and forage to support both species. If so, the local decline in Greenland White-fronted Goose...... on activity budgets and spatial distribution were obtained from observations of behaviour, and diet selection was determined through analyses of plant epidermal fragments in faecal samples that were subsequently genotyped to goose species. No differences in diet or spatial distribution of the two species were...

Feather mass and winter moult extent are heritable but not associated with fitness-related traits in a long-distance migratory bird

NARCIS (Netherlands)

De la Hera, I.; Reed, T.; Pulido, F.; Visser, M.E.

2013-01-01

In birds, the allocation of resources to plumage production may have important fitness consequences. However, we have only a limited understanding of how plumage traits respond to natural selection, making it difficult to predict how variation in plumage traits may contribute to the adaptation of

Linkage of the king eider population in Northeast Greenland: Migration, moult and discovery of a new offshore wintering area at Spitsbergenbanken

DEFF Research Database (Denmark)

Mosbech, Anders; Johansen, Kasper Lambert; Sonne, Christian

In late July 2009, two female king eiders were caught on the breeding grounds in Myggbukta, Northeast Greenland and equipped with satellite transmitters. Both individuals were tracked for approximately two years. The birds remained in the Myggbukta area until the onset of the autumn migration...... arrival 6 April) where they stayed for some time before returning on the spring migration to Greenland. During a ship-based survey in the offshore winter location at Spitsbergenbanken in April 2013, a previously unknown wintering ground with approximately 10.000 king eiders was discovered. The birds were...... concentrated in a partly ice-covered area 79 km from shore and of about 20 m depth. The number of king eiders indicated that Spitsbergenbanken is a wintering area for both the East Greenland and the Svalbard breeding populations. The discovery has important conservation implications due to the expanding...

Study of ethanol-lysozyme interactions using neutron diffraction

International Nuclear Information System (INIS)

Lehmann, M.S.; Mason, S.A.; McIntyre, G.J.

1985-01-01

Single-crystal neutron diffraction has been used to observe the interactions between deuterated ethanol (CD3CD2OH) and lysozyme in triclinic crystals of hen egg white lysozyme soaked in 25% (v/v) ethanol solutions. A total of 6047 observed reflections to a resolution of 2 A were used, and 13 possible ethanol sites were identified. The three highest occupied sites are close to locations for bromoethanol found in an earlier study by Yonath et al. [Yonath, A., Podjarny, A., Honig, B., Traub, W., Sielecki, A., Herzberg, O., and Moult, J. (1978) Biophys. Struct. Mech. 4, 27-36]. Structure refinements including a model for the flat solvent lead to a final crystallographic agreement factor of 0.097. Comparison with earlier neutron studies on triclinic lysozyme showed that neither the molecular structure nor the thermal motions were affected significantly by the ethanol. A detailed analysis of the ethanol-lysozyme contacts showed 61% of these to be with hydrophobic sites, in agreement with the dominant hydrophobic nature of ethanol. This, together with the fact that the molecular structure of lysozyme is not perturbed, suggests a model for denaturation of lysozyme by alcohol, which proceeds via a dehydration of the protein at high alcohol concentration

Hovering hummingbird wing aerodynamics during the annual cycle. I. Complete wing.

Science.gov (United States)

Achache, Yonathan; Sapir, Nir; Elimelech, Yossef

2017-08-01

The diverse hummingbird family (Trochilidae) has unique adaptations for nectarivory, among which is the ability to sustain hover-feeding. As hummingbirds mainly feed while hovering, it is crucial to maintain this ability throughout the annual cycle-especially during flight-feather moult, in which wing area is reduced. To quantify the aerodynamic characteristics and flow mechanisms of a hummingbird wing throughout the annual cycle, time-accurate aerodynamic loads and flow field measurements were correlated over a dynamically scaled wing model of Anna's hummingbird ( Calypte anna ). We present measurements recorded over a model of a complete wing to evaluate the baseline aerodynamic characteristics and flow mechanisms. We found that the vorticity concentration that had developed from the wing's leading-edge differs from the attached vorticity structure that was typically found over insects' wings; firstly, it is more elongated along the wing chord, and secondly, it encounters high levels of fluctuations rather than a steady vortex. Lift characteristics resemble those of insects; however, a 20% increase in the lift-to-torque ratio was obtained for the hummingbird wing model. Time-accurate aerodynamic loads were also used to evaluate the time-evolution of the specific power required from the flight muscles, and the overall wingbeat power requirements nicely matched previous studies.

Edible crabs "go west": migrations and incubation cycle of Cancer pagurus revealed by electronic tags.

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Ewan Hunter

Full Text Available Crustaceans are key components of marine ecosystems which, like other exploited marine taxa, show seasonable patterns of distribution and activity, with consequences for their availability to capture by targeted fisheries. Despite concerns over the sustainability of crab fisheries worldwide, difficulties in observing crabs' behaviour over their annual cycles, and the timings and durations of reproduction, remain poorly understood. From the release of 128 mature female edible crabs tagged with electronic data storage tags (DSTs, we demonstrate predominantly westward migration in the English Channel. Eastern Channel crabs migrated further than western Channel crabs, while crabs released outside the Channel showed little or no migration. Individual migrations were punctuated by a 7-month hiatus, when crabs remained stationary, coincident with the main period of crab spawning and egg incubation. Incubation commenced earlier in the west, from late October onwards, and brooding locations, determined using tidal geolocation, occurred throughout the species range. With an overall return rate of 34%, our results demonstrate that previous reluctance to tag crabs with relatively high-cost DSTs for fear of loss following moulting is unfounded, and that DSTs can generate precise information with regards life-history metrics that would be unachievable using other conventional means.

Seasonal and gender-related differences in morphometric features and cellular and biochemical parameters of Carcinus aestuarii from the Lagoon of Venice.

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Matozzo, Valerio; Boscolo, Alice; Marin, Maria Gabriella

2013-08-01

In this study, the seasonal variations in the morphometric features and in the cellular and biochemical parameters of the haemolymph were investigated in both male and female crabs (Carcinus aestuarii). Crabs were seasonally (November 2010-August 2011) collected from the Lagoon of Venice, and the moult stage, weight, width and length of the carapace, and width and length of the bigger chela were evaluated. In addition, the total haemocyte count (THC), haemocyte diameter and volume, haemolymph glucose and total protein levels, and haemolymph phenoloxidase (PO) and N-acetyl-β-glucosaminidase (NAG) activities were measured. The results demonstrated that the collected crabs were all in the intermoult stage and that the males were bigger than the females. A two-way ANOVA revealed a significant effect of season on the THC and the haemocyte volume and a significant influence of gender on the haemocyte diameter. Season and gender significantly affected the haemolymph glucose concentration, whereas haemolymph protein levels were dependent only on the season. In addition, both season and gender significantly influenced the PO and NAG activities in the haemolymph. Overall, the results demonstrated that crab morphometric features as well as haemolymph cellular and biochemical parameters varied markedly as a function of both season and gender. Copyright © 2013 Elsevier Ltd. All rights reserved.

Preliminary Investigation on the Toxicity of Different Formulations on Some Groups of Beneficial Arthropods in Emilia-Romagna Orchards

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Stefano Civolani

2007-06-01

Full Text Available Control of the most relevant phytophagous of apple and pear trees in Emilia-Romagna (Northern Italy is achieved by insecticides but it is improved also by defence techniques allowing protection of useful insects. It is therefore relevant to understand in detail the effects of the most common insecticides employed in integrated defence of the two above mentioned cultures on the main auxiliary insects, both predators and parasitoids. With this aim we performed open field tests to evaluate the acute toxicity (48 hours after the treatment, according to the method suggested by IOBC Working Group “Integrated Protection in Orchards” to test three recently developed active ingredient: Spinosad, Indoxacarb and Methoxyfenozide. These three principles were compared to Azinphos methyl, presently one of the most widely employed insecticides with a broad action spectrum. Spinosad is a natural insecticide compound, whose active principle is a toxin produced by Saccharopolispora spinosa, Indoxacarb and Methoxyfenozide are synthetic molecules, respectively belonging to the family of oxadiazines and moult accelerators, while Azinphos methyl is an organophosphate compound. The results show that Azinphos methyl is characterized by a lower selectivity towards generic Coccinellidae, while mortality towards Antochoris nemoralis is rather limited for all active principles tested, on the contrary to what observed for parasitoid Hymenoptera.

Comparison of metallothionein concentrations and tissue distribution of trace metals in crabs (Pachygrapsus marmoratus) from a metal-rich estuary, in and out of the reproductive season.

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Mouneyrac, C; Amiard-Triquet, C; Amiard, J C; Rainbow, P S

2001-07-01

Crabs, Pachygrapsus marmoratus, were sampled in June 1997 and February 1998 from two sites (at the mouth and 25 km upstream) in the metal-rich Gironde estuary, France. Gills and hepatopancreas were analysed for metal (Cd, Cu, Zn) and metallothionein (MT) contents, in order to examine the influence of both biological and environmental factors on the physico-chemical forms of detoxified metal storage in the crabs. The concentrations of MT and both cytosolic and insoluble metals were not greatly different between males and females, and the influence of organ weights was also minimal. Intersite differences were observed, probably resulting from the gradient of salinity in the estuary, which interacts with both the chemical speciation and bioavailability of metals, and the general protein metabolism of the crabs. Seasonal changes were also important, probably in interaction with the moult and reproductive cycles. In February, concentrations of insoluble metals were generally higher than in June, in both organs, suggesting that essential metals, particularly Zn, are stored during winter then remobilised during the breeding season. The natural variability in the concentrations of MT often concealed any relationship with accumulated metal concentrations. Thus MT in crabs cannot be considered as a useful biomarker of metal pollution.

Preliminary Investigation on the Toxicity of Different Formulations on Some Groups of Beneficial Arthropods in Emilia-Romagna Orchards

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Stefano Civolani

Full Text Available Control of the most relevant phytophagous of apple and pear trees in Emilia-Romagna (Northern Italy is achieved by insecticides but it is improved also by defence techniques allowing protection of useful insects. It is therefore relevant to understand in detail the effects of the most common insecticides employed in integrated defence of the two above mentioned cultures on the main auxiliary insects, both predators and parasitoids. With this aim we performed open field tests to evaluate the acute toxicity (48 hours after the treatment, according to the method suggested by IOBC Working Group “Integrated Protection in Orchards” to test three recently developed active ingredient: Spinosad, Indoxacarb and Methoxyfenozide. These three principles were compared to Azinphos methyl, presently one of the most widely employed insecticides with a broad action spectrum. Spinosad is a natural insecticide compound, whose active principle is a toxin produced by Saccharopolispora spinosa, Indoxacarb and Methoxyfenozide are synthetic molecules, respectively belonging to the family of oxadiazines and moult accelerators, while Azinphos methyl is an organophosphate compound. The results show that Azinphos methyl is characterized by a lower selectivity towards generic Coccinellidae, while mortality towards Antochoris nemoralis is rather limited for all active principles tested, on the contrary to what observed for parasitoid Hymenoptera.

Attraction of Male Nymphs to Adult Male Volatiles in the Bronze Bug Thaumastocoris peregrinus Carpintero & Dellape (Heteroptera: Thaumastocoridae).

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Calvo, M V; Groba, H F; Martínez, G; Sellanes, C; Rossini, C; González, A

2017-12-23

The bronze bug, Thaumastocoris peregrinus Carpintero & Dellape (Heteroptera: Thaumastocoridae), is an exotic emerging pest in Eucalyptus commercial forests in South America, Africa and southern Europe. Information on the chemical communication system and reproductive ecology of this insect is scant, and it may be relevant for designing management strategies for eucalypt plantations. Adults and nymphs usually aggregate in the field, possibly by means of chemical signals. Males emit large amounts of 3-methyl-2-butenyl butyrate, which attracts conspecific adult males but not females. The ecological role of this putative male aggregation pheromone remains unknown. Here, we report olfactometer bioassays showing that late-instar male nymphs are also attracted to synthetic 3-methyl-2-butenyl butyrate and to adult male volatile extracts, which contain this compound as the major component. As previously shown for adult females, nymphs that moulted into females were not attracted to either volatile stimulus. The intra-gender attraction of nymphs and adults may be related to the exploitation of food resources, or as a reproductive strategy for newly emerged males. Further studies on the reproductive behaviour and mating system of T. peregrinus will contribute to understanding the ecological significance of male-male, adult-nymph attraction, as well as the practical applications that may result from these findings.

The larval nervous system of the penis worm Priapulus caudatus (Ecdysozoa).

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Martín-Durán, José M; Wolff, Gabriella H; Strausfeld, Nicholas J; Hejnol, Andreas

2016-01-05

The origin and extreme diversification of the animal nervous system is a central question in biology. While most of the attention has traditionally been paid to those lineages with highly elaborated nervous systems (e.g. arthropods, vertebrates, annelids), only the study of the vast animal diversity can deliver a comprehensive view of the evolutionary history of this organ system. In this regard, the phylogenetic position and apparently conservative molecular, morphological and embryological features of priapulid worms (Priapulida) place this animal lineage as a key to understanding the evolution of the Ecdysozoa (i.e. arthropods and nematodes). In this study, we characterize the nervous system of the hatching larva and first lorica larva of the priapulid worm Priapulus caudatus by immunolabelling against acetylated and tyrosinated tubulin, pCaMKII, serotonin and FMRFamide. Our results show that a circumoral brain and an unpaired ventral nerve with a caudal ganglion characterize the central nervous system of hatching embryos. After the first moult, the larva attains some adult features: a neck ganglion, an introvert plexus, and conspicuous secondary longitudinal neurites. Our study delivers a neuroanatomical framework for future embryological studies in priapulid worms, and helps illuminate the course of nervous system evolution in the Ecdysozoa. © 2015 The Authors.

Innovative layer genetics to handle global challenges in egg production.

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Preisinger, Rudolf

2018-02-01

1. In commercial layer breeding, extensive gene pools are tested and selected for market requirements which must be anticipated at least 5 years ahead. Field results confirm a continuous positive genetic trend in egg output and better feed efficiency which can be converted into land savings. 2. Animal welfare and cage-free housing dominate future needs of the market. Nesting behaviour and minimal tendency to develop feather-pecking or cannibalism without beak treatment are key trait complexes. Stronger shells for longer production cycles without moulting have to be combined with better bones. 3. No single big gene effect can be expected to control the multifactorial problem of feather-pecking. Adjusting the shape of the beak, with a heritability of .10-.25, can contribute to reducing the risk of severe cannibalism. 4. For better skeletal integrity, the assessment of bone quality in pedigree birds housed in enriched cages is done by keel bone palpation or ultrasound measurement of the humerus. Both traits show similar heritabilities in the range of .15-.30 and can be included in a balanced selection approach for performance, quality and welfare traits. 5. The combination of performance testing and genome-wide DNA marker analysis is a promising tool to generate more progress for a balanced performance and behaviour profile.

YEAR CYCLE OF AUSTROPOTAMOBIUS TORRENTIUM (SCHRANK IN STREAMS ON MEDVEDNICA MOUNTAIN (CROATIA.

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MAGUIRE I.

2002-07-01

Full Text Available We studied life cycle of stone crayfish for 18 months in three streams on Medvednica Mountain, located above city of Zagreb. Sampling of animals was carried out with baited traps twice a month and various physiological functions were recorded. Sex ratio of trapped crayfish was 1:1, but it fluctuated during the year. Animals were active from early spring until the beginning of November when their activities significantly decreased. In this period we noticed three peaks of higher activity. The first one after winter starvation in March, the second one after egg hatching (June/July and the third one during mating period (end of September - beginning of November. The maximal recorded weight for female was 38 g while the heaviest male was 55 g. The longest female was 9.28 cm and male 10.30 cm. Development of glair glands started from the end of July, mating occurred at the end of October and the juveniles hatched until mid-June. Freshly moulted animals were found from mid-May until mid-October. Main injuries were claw and limb loss. We noticed the presence of burn spot disease and Branchiobdella parasita Henle within studied populations. Correlation with five different physico-chemical parameters of water showed that animals’ activity is positively correlated to water temperature, conductivity, pH and hardness and negatively to oxygen concentration.

Life stages of an aphid living under similar thermal conditions differ in thermal performance.

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Zhao, Fei; Hoffmann, Ary A; Xing, Kun; Ma, Chun-Sen

2017-05-01

Heat responses can vary ontogenetically in many insects with complex life cycles, reflecting differences in thermal environments they experience. Such variation has rarely been considered in insects that develop incrementally and experience common microclimates across stages. To test if there is a low level of ontogenetic variation for heat responses in one such species, the English grain aphid Sitobion avenae, basal tolerance [upper lethal temperature (ULT 50 ) and maximum critical temperature (CT max )], hardening capacity (CT max ) and hardening costs (adult longevity and fecundity) were measured across five stages (1st, 2nd, 3rd and 4th-instar nymphs and newly moulted adults). We found large tolerance differences among stages of this global pest species, and a tendency for the stage with lower heat tolerance to show a stronger hardening response. There were also substantial reproductive costs of hardening responses, with the level of stress experienced, and not the proximity of the exposed stage to the reproductive adult stage, influencing the magnitude of this cost. Hence hardening in this aphid may counter inherently low tolerance levels of some life stages but at a cost to adult longevity and fecundity. Our findings highlight the significance of ontogenetic variation in predicting responses of a species to climate change, even in species without a complex life cycle. Copyright © 2017 Elsevier Ltd. All rights reserved.

Ultrastructural observations of target-organs of the crayfish Orconectes limosus exposed to metallic pollutants: application to uranium

International Nuclear Information System (INIS)

Grasset, G.; Simon, O.; Floriani, M.

2004-01-01

Using electron microscopy associated with energy dispersive X-ray microanalysis (EDAXTEM), ultrastructure and elemental analysis in subcellular micro-localization can bring understanding to both metabolic cycle of a metallic pollutant and its potential effects at the subcellular scale. The approach consists in comparing both structures and micro-localization in various tissues/organs ultrathin sections (70-140 nm thickness) obtained from control organisms (i.e. not exposed to a given metal) and exposed organisms. However, the observations of ultrastructural effects of metal exposure involved robust comparison to reference subcellular and cellular organization. Consequently, preliminary developments presented in this poster have been performed from the non-contaminated freshwater crayfish Orconectes limosus (adult at inter-moult state). Studies of ultrastructural images and elemental composition of subcellular mineral deposits were carried out on target organs of uranium accumulation such as the digestive gland, the gills, the intestine and the antennal gland, organs participating in the detoxification, primary accumulation and depuration mechanisms. Observations indicated cell-specific architecture (identification of main organelles, frequency, length of cells), the range of natural variation of the cell organisation between individuals and identification of cellular types. Information will allow then to focus on these identified specific organization after metallic exposure. These ultrastructural observations performed on reference organisms constitute necessarily a first set of data for the cellular metallic effects analysis. (author)

Bird surveys at McKinley Bay and Hutchinson Bay, Northwest Territories, in 1990

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Cornish, B J; Dickson, D L; Dickson, H L

1991-03-01

Monitoring surveys of bird abundance and distribution were conducted in 1990 at McKinley Bay in the Northwest Territories, the site of a winter harbour for drillships and the proposed location for a major year-round support base for oil and gas exploration. Primary objectives of the survey were to determine whether diving duck numbers had changed since the initial phase of the study from 1981-1985, and to provide additional baseline data on natural annual fluctuations in diving duck numbers. Three aerial surveys at each bay were carried out using techniques identical to those in previous years. On 5 August 1990, when survey conditions were considered best of the three surveys, more than twice as many diving ducks were found in McKinley Bay and Hutchinson Bay than on average during the five years of 1981-1985. Old squaw and scooters comprised ca 90% of the diving ducks observed, and both species showed significant increases in numbers. The increase in abundance of diving ducks was likely unrelated to industrial activity in the area since a similar increase occurred in the control area, Hutchinson Bay. Many factors, including both environmental factors such as those affecting nesting success and timing of the moult, and factors related to the survey methods, could be involved in causing the large fluctuations observed. 9 refs., 8 figs., 10 tabs.

The biology of three Mexican-American species of Triatominae (Hemiptera: Reduviidae: Triatoma recurva, Triatoma protracta and Triatoma rubida

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José Alejandro Martínez-Ibarra

2012-08-01

Full Text Available The values of biological parameters related to hatching, lifespan, the number of blood meals between moults, mortality, time lapse before the beginning of feeding, feeding time and defecation delay for each instar of three Mexican-American species of Triatominae, Triatoma recurva, Triatoma protracta (former subspecies protracta and Triatoma rubida (former subspecies uhleri, were evaluated and compared. No significant (p > 0.05 differences were recorded among the three species with respect to the average time required to hatch. This time was approximately 19 days. The average egg-to-adult development time was significantly (p < 0.05 shorter for T. rubida. The number of blood meals at each nymphal instar varied from one-five for each species. The mortality rates were higher for the first-instar nymphs of the three species studied. The mean time lapse before the beginning of feeding was between 0.3-3 min for most nymphs of all instars of each species studied. The mean feeding time was the longest for T. recurva, followed by T. protracta. The defecation delay was less than 10 min for T. recurva and T. rubida. Given these results, only T. rubida should be considered an important potential vector of Trypanosoma cruzi transmission to humans in areas of Mexico where these species exist, whereas T. recurva and T. protracta would be of secondary importance.

Bird surveys at McKinley Bay and Hutchinson Bay, Northwest Territories, in 1990

International Nuclear Information System (INIS)

Cornish, B.J.; Dickson, D.L.; Dickson, H.L.

1991-01-01

Monitoring surveys of bird abundance and distribution were conducted in 1990 at McKinley Bay in the Northwest Territories, the site of a winter harbour for drillships and the proposed location for a major year-round support base for oil and gas exploration. Primary objectives of the survey were to determine whether diving duck numbers had changed since the initial phase of the study from 1981-1985, and to provide additional baseline data on natural annual fluctuations in diving duck numbers. Three aerial surveys at each bay were carried out using techniques identical to those in previous years. On 5 August 1990, when survey conditions were considered best of the three surveys, more than twice as many diving ducks were found in McKinley Bay and Hutchinson Bay than on average during the five years of 1981-1985. Old squaw and scooters comprised ca 90% of the diving ducks observed, and both species showed significant increases in numbers. The increase in abundance of diving ducks was likely unrelated to industrial activity in the area since a similar increase occurred in the control area, Hutchinson Bay. Many factors, including both environmental factors such as those affecting nesting success and timing of the moult, and factors related to the survey methods, could be involved in causing the large fluctuations observed. 9 refs., 8 figs., 10 tabs

Emerging fungal pathogen Ophidiomyces ophiodiicola in wild European snakes

Science.gov (United States)

Franklinos, Lydia H. V.; Lorch, Jeffrey M.; Bohuski, Elizabeth A.; Rodriguez-Ramos Fernandez, Julia; Wright, Owen; Fitzpatrick, Liam; Petrovan, Silviu; Durrant, Chris; Linton, Chris; Baláž, Vojtech; Cunningham, Andrew A; Lawson, Becki

2017-01-01

Snake fungal disease (SFD) is an emerging disease of conservation concern in eastern North America. Ophidiomyces ophiodiicola, the causative agent of SFD, has been isolated from over 30 species of wild snakes from six families in North America. Whilst O. ophiodiicola has been isolated from captive snakes outside North America, the pathogen has not been reported from wild snakes elsewhere. We screened 33 carcasses and 303 moulted skins from wild snakes collected from 2010–2016 in Great Britain and the Czech Republic for the presence of macroscopic skin lesions and O. ophiodiicola. The fungus was detected using real-time PCR in 26 (8.6%) specimens across the period of collection. Follow up culture and histopathologic analyses confirmed that both O. ophiodiicola and SFD occur in wild European snakes. Although skin lesions were mild in most cases, in some snakes they were severe and were considered likely to have contributed to mortality. Culture characterisations demonstrated that European isolates grew more slowly than those from the United States, and phylogenetic analyses indicated that isolates from European wild snakes reside in a clade distinct from the North American isolates examined. These genetic and phenotypic differences indicate that the European isolates represent novel strains of O. ophiodiicola. Further work is required to understand the individual and population level impact of this pathogen in Europe.

Does sugar content matter? Blood plasma glucose levels in an occasional and a specialist avian nectarivore.

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Witteveen, Minke; Brown, Mark; Downs, Colleen T

2014-01-01

Nectar composition within a plant pollinator group can be variable, and bird pollinated plants can be segregated into two groups based on their adaptations to either a specialist or an occasional bird pollination system. Specialist nectarivores rely primarily on nectar for their energy requirements, while occasional nectarivores meet their energy requirements from nectar as well as from seeds, fruit and insects. Avian blood plasma glucose concentration (PGlu) is generally high compared with mammals. It is also affected by a range of factors including species, gender, age, ambient temperature, feeding pattern, reproductive status, circadian rhythm and moult status, among others. We examined whether sugar content affected PGlu of two avian nectarivores, a specialist nectarivore the Amethyst Sunbird Chalcomitra amethystina, and an occasional nectarivore the Cape White-eye Zosterops virens, when fed sucrose-hexose sugar solution diets of varying concentrations (5%-35%). Both species regulated PGlu within a range which was affected by sampling time (fed or fasted) and not dietary sugar concentration. The range in mean PGlu was broader in Amethyst Sunbirds (11.52-16.51mmol/L) compared with Cape White-eyes (14.33-15.85mmol/L). This suggests that these birds are not constrained by dietary sugar concentration with regard to PGlu regulation, and consequently selective pressure on plants for their nectar characteristics is due to reasons other than glucose regulation. © 2013.

ANNUAL ACTIVITY OF THE NOBLE CRAYFISH (ASTACUS ASTACUS IN THE ORLJAVA RIVER (CROATIA

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FALLER M.

2006-07-01

Full Text Available We studied the annual activity of the noble crayfish (Astacus astacus at three sites along the Orljava River, in the continental part of Croatia, between August 2003 and September 2004. Each site represented the typical characteristics of the upper, middle and lower section of the river (5, 24 and 37 km from the spring, respectively. The biggest population size was recorded on the most upstream site, with greatest structural variability of bottom, high biotic index, and the lowest mean water temperature. Males dominated in catch during the whole research period (total sex ratio was 1.77 males: 1 female. The number of caught crayfish fluctuated during the year and their activity was positively correlated with the water temperature. The crayfish catch within the two downstream sites was dramatically lower in the autumn 2004 then the year before. No obvious reason could be found; therefore we concluded that this was probably result of natural fluctuations in population. Males were significantly longer than females on all three sites. Males and females had similar percentages of injuries, mainly on claws and antennae. Crayfish were active during the whole year, even when water temperature was just 1°C. Phases of life cycle (moulting, active cement glands, mating, hatchlings occurred a month later in our population than in the Northern Europe populations, probably as a consequence of differences in the climate.

A scanning electron microscopy study of early development in vitro of Contracaecum multipapillatum s.l. (Nematoda: Anisakidae) from a brown pelican (Pelecanus occidentalis) from the Gulf of California, Mexico.

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Molina-Fernández, Dolores; Valles-Vega, Isabel; Hernández-Trujillo, Sergio; Adroher, Francisco Javier; Benítez, Rocío

2017-10-01

Eggs obtained from the uteri of female nematodes, genetically identified as Contracaecum multipapillatum s.l., found in a brown pelican (Pelecanus occidentalis) from Bahía de La Paz, Gulf of California, Mexico, were used to study the early developmental stages of this anisakid by scanning electron microscopy (SEM). Egg dimensions were approximately 54 × 45 μm measured by SEM. Observation of the eggs revealed an outer surface of fibrous appearance. The newly hatched larvae were ensheathed and highly motile. Observation with SEM showed that the sheaths of the larvae were striated and revealed an excretory pore and a cleft near the anterior end of the sheath, presumably to facilitate the opening of the sheath for the emergence of the larva. The hatched larvae were placed in nutritive culture medium, where they grew within their sheath, some exsheathing completely 2 weeks later. The surface patterns of the sheath and the cuticle of the exsheathed larvae were clearly different. Although they did not moult during culture, SEM revealed a morphology typical of third-stage larvae of Contracaecum from fish, as previously observed by optical microscopy. Thus, we suggest that newly hatched larvae from eggs of C. multipapillatum are third larval stage but with sheath of the second larval stage, as occuring in other anisakids.

Molecular basis for the reproductive division of labour in a lower termite

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Rehli Michael

2007-06-01

Full Text Available Abstract Background Polyphenism, the expression of different phenotypes with the same genetic background, is well known for social insects. The substantial physiological and morphological differences among the castes generally are the result of differential gene expression. In lower termites, workers are developmentally flexible to become neotenic replacement reproductives via a single moult after the death of the founding reproductives. Thus, both castes (neotenics and workers are expected to differ mainly in the expression of genes linked to reproductive division of labour, which constitutes the fundamental basis of insect societies. Results Representational difference analysis of cDNAs was used to study differential gene expression between neotenics and workers in the drywood termite Cryptotermes secundus (Kalotermitidae. We identified and, at least partially cloned five novel genes that were highly expressed in female neotenics. Quantitative real-time PCR analysis of all five genes in different castes (neotenics, founding reproductives, winged sexuals and workers of both sexes confirmed the differential expression patterns. In addition, the relative expression of these genes was determined in three body parts of female neotenics (head, thorax, and abdomen using quantitative real-time PCR. Conclusion The identified genes could be involved in the control and regulation of reproductive division of labour. Interestingly, this study revealed an expression pattern partly similar to social Hymenoptera indicating both common and species-specific regulatory mechanisms in hemimetabolous and holometabolous social insects.

Transcriptomic analysis of Portunus trituberculatus reveals a critical role for WNT4 and WNT signalling in limb regeneration.

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Liu, Lei; Fu, Yuanyuan; Zhu, Fang; Mu, Changkao; Li, Ronghua; Song, Weiwei; Shi, Ce; Ye, Yangfang; Wang, Chunlin

2018-06-05

The swimming crab (Portunus trituberculatus) is among the most economically important seawater crustacean species in Asia. Despite its commercial importance and being well-studied status, genomic and transcriptomic data are scarce for this crab species. In the present study, limb bud tissue was collected at different developmental stages post amputation for transcriptomic analysis. Illumina RNA-sequencing was applied to characterise the limb regeneration transcriptome and identify the most characteristic genes. A total of 289,018 transcripts were obtained by clustering and assembly of clean reads, producing 150,869 unigenes with an average length of 956 bp. Subsequent analysis revealed WNT signalling as the key pathway involved in limb regeneration, with WNT4 a key mediator. Overall, limb regeneration appears to be regulated by multiple signalling pathways, with numerous cell differentiation, muscle growth, moult, metabolism, and immune-related genes upregulated, including WNT4, LAMA, FIP2, FSTL5, TNC, HUS1, SWI5, NCGL, SLC22, PLA2, Tdc2, SMOX, GDH, and SMPD4. This is the first experimental study done on regenerating claws of P. trituberculatus. These findings expand existing sequence resources for crab species, and will likely accelerate research into regeneration and development in crustaceans, particularly functional studies on genes involved in limb regeneration. Copyright © 2018 Elsevier B.V. All rights reserved.

Effects of the Tunoe Knob offshore wind farm on birdlife

International Nuclear Information System (INIS)

Guillemette, M.; Kyed Larsen, J.; Clausager, I.

1997-01-01

As part of the plans of the Danish government to expand offshore wind energy production, The Ministry of Environment and Energy, in collaboration with the Danish power companies, initiated a three-year study of the effects of the Tunoe Knob offshore wind farm on bird life. The aim of this study was to investigate the potential conflict between offshore wind farms and water birds. Danish coastal waters support very large, internationally important concentrations of moulting, migrating and wintering water birds which depend on shallow water areas as major feeding habitats. The wind farm was established at Tunoe Knob, a shoal in Aarhus Bugt, and consisted of ten 500 kW turbines erected in 3-5 m of water during the late summer of 1995. All studies were carried out during the winter period, and results are reported for eider Somateria mollissima and common scoter Melanitta nigra, which composed the great majority of the bird population. In the part of Tunoe knob where the wind farm was build, eider numbers decreased markedly over the study period. However, this decline was comparable to that observed on other parts of Tunoe Knob. Furthermore, detailed mapping showed a high degree of annual and within season variation in spatial distribution over the area, including occurrence in the immediate vicinity of the wind farm. These results suggest that the observed changes in eider numbers in the wind farm area were due to natural variation. (EG) 21 refs

Biology of Dermacentor marginatus (Acari: Ixodidae under laboratory conditions

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Mohammad Mehdi Darvishi

2014-02-01

Full Text Available Objective: To investigate and survey the biology of Dermacentor marginatus (D. marginatus under laboratory conditions. Methods: In this investigation, D. marginatus adult ticks were collected from sheep in Semnan province. Then various developmental stages of D. marginatus including larvae, nymphs and adult males and females under laboratory condition were bred and their biology was scrutinized. Results: The requisite time to complete the life cycle of D. marginatus under controlled laboratory conditions for larvae (26 °C, 75% relative humidity and nymph (26 °C, 95% relative humidity moulting, was on average 92 d (range 75-104 d, including preoviposition and egg incubation (22.5 d, larvae incubation (20.5 d, nymphal stage (28 d along with male maturation (21 d. The index of conversion efficiency and the index of reproduction efficiency in females were 0.397 and 8.300, respectively. Conclusions: Although in this investigation, there was no meaningful correlation between preoviposition period and the weight of female ticks which were laid successfully. The significant linear relationship was fully observed between the weight of engorged female of D. marginatus and the number of eggs laid. The mean of preoviposition period from 5.4 d in autumn to 34.2 d in spring increased. The minimum weight of ticks with laying capacity was 69 mg and lighter ticks (21 mg either did not lay or if they did their eggs did not hatch.

Metal and metalloid bioaccumulation in the Pacific blue shrimp Litopenaeus stylirostris (Stimpson) from New Caledonia: Laboratory and field studies

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Metian, Marc; Hedouin, Laetitia; Eltayeb, Mohamed M.; Lacoue-Labarthe, Thomas; Teyssie, Jean-Louis; Mugnier, Chantal; Bustamante, Paco; Warnau, Michel

2010-01-01

The present work aimed at better understanding metal and metalloid bioaccumulation in the edible Pacific blue shrimp Litopenaeus stylirostris, using both laboratory and field approaches. In the laboratory, the bioaccumulation kinetics of Ag, Cd, Co, Cr, and Zn have been investigated in shrimp exposed via seawater and food, using the corresponding γ-emitting radiotracers ( 110m Ag, 109 Cd, 57 Co, 51 Cr, and 65 Zn) and highly sensitive nuclear detection techniques. Results showed that hepatopancreas and intestine concentrated the metals to the highest extent among the blue shrimp organs and tissues. Moulting was found to play a non negligible detoxification role for Co, Cr and, to a lesser extent, Zn. Metal retention by L. stylirostris widely varied (from a few days to several months), according to the element and exposure pathway considered (a given metal was usually less strongly retained when ingested with food than when it was taken up from the dissolved phase). In the field study, Ag, As, Cd, Co, Cr, Cu, Mn, Ni, and Zn were analysed in shrimp collected from a New Caledonian aquaculture pond. Metal concentrations in the shrimp muscles were generally relatively low and results confirmed the role played by the digestive organs and tissues in the bioaccumulation/storage/detoxification of metals in the Pacific blue shrimp. Preliminary risk considerations indicate that consumption of the shrimp farmed in New Caledonia is not of particular concern for human health.

Plasma thyroid hormone pattern in king penguin chicks: a semi-altricial bird with an extended posthatching developmental period.

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Cherel, Yves; Durant, Joël M; Lacroix, André

2004-05-01

Plasma concentrations of thyroid hormones (TH) were investigated during the extended posthatching developmental period (approximately 11 months) of a semi-altricial bird species, the king penguin (Aptenodytes patagonicus). The first period of growth in summer was marked by a progressive rise in plasma T4 concentration that paralleled rapid increases in body mass and in structural and down growth. By contrast, plasma T3 concentration had already reached adult levels in newly hatched chicks and did not change thereafter. Circulating TH of king penguin chicks thus follow an original pattern when comparing to altricial and precocial species. During the austral winter, the long period of undernutrition of king penguin chicks was characterized by a decrease in circulating TH that can be related to a seasonal stop in growth and energy saving mechanisms. Plasma TH concentrations increased again during the second growth phase in spring, and they reached their highest levels at the end of the fledging period, slightly before juveniles initiated their first foraging trip at sea. As expected, plasma T4 levels were elevated when chicks moulted, developing a true-adult type waterproof plumage. The data also suggest that T4 plays a major role in skeletal development and pectoral muscle maturation in anticipation of marine life. Plasma T3 was at its highest during the period when juveniles improved resistance to cold waters by going back and forth to the sea, suggesting a role for circulating T3 in cold acclimatization occurring at that time.

Bioaccumulation, distribution and elimination of chlordecone in the giant freshwater prawn Macrobrachium rosenbergii: Field and laboratory studies.

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Lafontaine, Anne; Gismondi, Eric; Dodet, Nathalie; Joaquim-Justo, Célia; Boulangé-Lecomte, Céline; Caupos, Fanny; Lemoine, Soazig; Lagadic, Laurent; Forget-Leray, Joëlle; Thomé, Jean-Pierre

2017-10-01

Chlordecone is a persistent organochlorine pesticide that has been widely used in Guadeloupe (French West Indies) to control the banana weevil Cosmopolites sordidus from 1972 to 1993. A few years after its introduction, widespread contamination of soils, rivers, wild animals and aquatic organisms was reported. Although high chlordecone concentrations have been reported in several crustacean species, its uptake, internal distribution, and elimination in aquatic species have never been described. This study aimed at investigating the accumulation and tissue distribution of chlordecone in the giant freshwater prawn Macrobrachium rosenbergii, using both laboratory (30 days exposure) and field (8 months exposure) approaches. In addition, depuration in chlordecone-free water was studied. Results showed that chlordecone bioconcentration in prawns was dose-dependent and time-dependent. Moreover, females appeared to be less contaminated than males after 5 and 7 months of exposure, probably due to successive spawning leading in the elimination of chlordecone through the eggs. Chlordecone distribution in tissues of exposed prawns showed that cephalothorax organs, mainly represented by the hepatopancreas, was the most contaminated. Results also showed that chlordecone was accumulated in cuticle, up to levels of 40% of the chlordecone body burden, which could be considered as a depuration mechanism since chlordecone is eliminated with the exuviae during successive moults. Finally, this study underlined the similarity of results obtained in laboratory and field approaches, which highlights their complementarities in the chlordecone behaviour understanding in M. rosenbergii. Copyright © 2017 Elsevier Ltd. All rights reserved.

Metamorphosis in the Cirripede Crustacean Balanus amphitrite

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Maruzzo, Diego; Aldred, Nick; Clare, Anthony S.; Høeg, Jens T.

2012-01-01

Stalked and acorn barnacles (Cirripedia Thoracica) have a complex life cycle that includes a free-swimming nauplius larva, a cypris larva and a permanently attached sessile juvenile and adult barnacle. The barnacle cyprid is among the most highly specialized of marine invertebrate larvae and its settlement biology has been intensively studied. By contrast, surprisingly few papers have dealt with the critical series of metamorphic events from cementation of the cyprid to the substratum until the appearance of a suspension feeding juvenile. This metamorphosis is both ontogenetically complex and critical to the survival of the barnacle. Here we use video microscopy to present a timeline and description of morphological events from settled cyprid to juvenile barnacle in the model species Balanus amphitrite, representing an important step towards both a broader understanding of the settlement ecology of this species and a platform for studying the factors that control its metamorphosis. Metamorphosis in B. amphitrite involves a complex sequence of events: cementation, epidermis separation from the cypris cuticle, degeneration of cypris musculature, rotation of the thorax inside the mantle cavity, building of the juvenile musculature, contraction of antennular muscles, raising of the body, shedding of the cypris cuticle, shell plate and basis formation and, possibly, a further moult to become a suspension feeding barnacle. We compare these events with developmental information from other barnacle species and discuss them in the framework of barnacle settlement ecology. PMID:22666355

Metabolic responses of the isopod Porcellionides pruinosus to nickel exposure assessed by (1)H NMR metabolomics.

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Ferreira, Nuno G C; Saborano, Raquel; Morgado, Rui; Cardoso, Diogo N; Rocha, Cláudia M; Soares, Amadeu M V M; Loureiro, Susana; Duarte, Iola F

2016-03-30

This work aimed at characterizing the metabolome of the isopod Porcellionides pruinosus and at assessing its variations over 14 days under laboratory culture conditions and upon exposure to the contaminant metal Nickel (Ni). The spectral profiles obtained by (1)H NMR spectroscopy were thoroughly assigned and subjected to multivariate analysis in order to highlight consistent changes. Over 50 metabolites could be identified, providing considerable new knowledge on the metabolome of these model organisms. Several metabolites changed non-linearly with Ni dose and exposure time, showing distinct variation patterns for initial (4 days) and later time points (7 and 14 days). In particular, at day 4, several amino acids were increased and sugars were decreased (compared to controls), whereas these variations were inverted for longer exposure, possibly reflecting earlier and more intensive moulting. Other variations, namely in betaines and choline-containing compounds, were suggested to relate with osmoregulation and detoxification mechanisms. Ni also had a marked effect on several nucleotides (increased upon exposure) and a moderate impact on lipids (decreased upon exposure). Overall, this study has provided new information on the Ni-induced metabolic adaptations of the P. pruinosus isopod, paving the way for improved mechanistic understanding of how these model organisms handle soil contamination. This study provided, for the first time to our knowledge, a detailed picture of the NMR-detectable metabolome of terrestrial isopods and of its fluctuations in time and upon exposure to the contaminant metal Nickel. Several time- and dose-dependent changes were highlighted, providing mechanistic insight into how these important model organisms handle Ni contamination.

Investigating the genetic and epigenetic basis of big biological questions with the parthenogenetic marbled crayfish: A review and perspectives.

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Vogt, Gunter

2018-03-01

In the last 15 years, considerable attempts have been undertaken to develop the obligately parthenogenetic marbled crayfish Procambarus virginalis as a new model in biology. Its main advantage is the production of large numbers of offspring that are genetically identical to the mother, making this crustacean particularly suitable for research in epigenetics. Now, a draft genome, transcriptome and genome-wide methylome are available opening new windows for research. In this article, I summarize the biological advantages and genomic and epigenetic features of marbled crayfish and, based on first promising data, discuss what this new model could contribute to answering of ''big'' biological questions. Genome mining is expected to reveal new insights into the genetic specificities of decapod crustaceans, the genetic basis of arthropod reproduction, moulting and immunity, and more general topics such as the genetic underpinning of adaptation to fresh water, omnivory, biomineralization, sexual system change, behavioural variation, clonal genome evolution, and resistance to cancer. Epigenetic investigations with the marbled crayfish can help clarifying the role of epigenetic mechanisms in gene regulation, tissue specification, adult stem cell regulation, cell ageing, organ regeneration and disease susceptibility. Marbled crayfish is further suitable to elucidate the relationship between genetic and epigenetic variation, the transgenerational inheritance of epigenetic signatures and the contribution of epigenetic phenotype variation to the establishment of social hierarchies, environmental adaptation and speciation. These issues can be tackled by experiments with highly standardized laboratory lineages, comparison of differently adapted wild populations and the generation of genetically and epigenetically edited strains.

Acquisition of epibiotic bacteria along the life cycle of the hydrothermal shrimp Rimicaris exoculata.

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Guri, Mathieu; Durand, Lucile; Cueff-Gauchard, Valérie; Zbinden, Magali; Crassous, Philippe; Shillito, Bruce; Cambon-Bonavita, Marie-Anne

2012-03-01

The caridean shrimp Rimicaris exoculata dominates the fauna at several Mid-Atlantic Ridge hydrothermal vent sites. This shrimp has an enlarged gill chamber, harboring a dense ectosymbiotic community of chemoautotrophic bacteria associated with mineral oxide deposits. Until now, their acquisition is not fully understood. At three hydrothermal vent sites, we analyzed the epibionts diversity at different moult stages and also in the first stages of the shrimp life (eggs, hatched eggs (with larvae) and juveniles). Hatched eggs associated with young larvae were collected for the first time directly from gravid females at the Logachev vent site during the Serpentine cruise. An approach using 16S rRNA clone libraries, scanning and transmission electron microscopy, and fluorescent in situ hybridization was used. Molecular results and microscope observations indicated a switch in the composition of the bacterial community between early R. exoculata life cycle stage (egg libraries dominated by the Gammaproteobacteria) and later stages (juvenile/adult libraries dominated by the Epsilonproteobacteria). We hypothesized that the epibiotic phylotype composition could vary according to the life stage of the shrimp. Our results confirmed the occurrence of a symbiosis with Gammaproteobacteria and Epsilonproteobacteria, but more complex than previously assumed. We revealed the presence of active type-I methanotrophic bacteria colonizing the cephalothorax of shrimps from the Rainbow site. They were also present on the eggs from the Logachev site. This could be the first 'epibiotic' association between methanotrophic bacteria and hydrothermal vent crustacean. We discuss possible transmission pathways for epibionts linked to the shrimp life cycle.

Diversity of developmental patterns in achelate lobsters-today and in the Mesozoic.

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Haug, Joachim T; Audo, Denis; Charbonnier, Sylvain; Haug, Carolin

2013-11-01

Modern achelate lobsters, slipper and spiny lobsters, have a specific post-embryonic developmental pattern with the following phases: phyllosoma, nisto (slipper lobsters) or puerulus (spiny lobsters), juvenile and adult. The phyllosoma is a peculiar larva, which transforms through a metamorphic moult into another larval form, the nisto or puerulus which largely resembles the juvenile. Unlike the nisto and puerulus, the phyllosoma is characterised by numerous morphological differences to the adult, e.g. a thin head shield, elongate appendages, exopods on these appendages and a special claw. Our reinvestigation of the 85 million years old fossil "Eryoneicus sahelalmae" demonstrates that it represents an unusual type of achelatan lobster larva, characterised by a mixture of phyllosoma and post-phyllosoma characters. We ascribe it to its own genus: Polzicaris nov. gen. We study its significance by comparisons with other cases of Mesozoic fossil larvae also characterised by a mixture of characters. Accordingly, all these larvae are interpreted as ontogenetic intermediates between phyllosoma and post-phyllosoma morphology. Remarkably, most of the larvae show a unique mixture of retained larval and already developed post-larval features. Considering the different-and incompatible-mixture of characters of each of these larvae and their wide geographical and temporal distribution, we interpret all these larvae as belonging to distinct species. The particular character combinations in the different larvae make it currently difficult to reconstruct an evolutionary scenario with a stepwise character acquisition. Yet, it can be concluded that a larger diversity of larval forms and developmental patterns occurred in Mesozoic than in modern faunas.

Survival benefits of post-fledging care: experimental approach to a critical part of avian reproductive strategies.

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Grüebler, Martin U; Naef-Daenzer, Beat

2010-03-01

1. Caring for offspring beyond leaving the nest is an important but under-studied part of avian life histories. Theory predicts that prolonged post-fledging parental care should yield fitness benefits such as increased fledgling survival. Post-fledging care is also costly in terms of time and energy available for subsequent reproduction, moult or migration. So far, direct measurements of the fitness effects of the duration of post-fledging parental care are lacking. 2. In a partial cross-fostering experiment, barn swallow (Hirundo rustica) chicks were exchanged among broods close to fledging. Thereby, we separated the effects of post-fledging care from those of pre-fledging origin on juvenile survival. 3. Prolonging post-fledging care substantially increased juvenile survival up to 3 weeks post-fledging. Juvenile mortality was maximal in the days following the termination of parental care, and prolonging care delayed and reduced this peak mortality. Survival of fledglings experiencing 6 days of care was Phi = 0.227, whereas fledglings experiencing 14 days of care showed a survival of Phi = 0.571. 4. Offspring from pairs providing short care showed lower post-fledging survival than did offspring from pairs providing long care, irrespective of the actual duration of care experienced. This gives evidence for an additional survival effect of pre-fledging factors associated with the parental duration of care. 5. The results suggest that differential survival in relation to post-fledging parental care is a major fitness component. This relationship has profound effects on the reproductive trade-offs underlying the evolution of avian life histories.

Short-term biochemical ill effects of insect growth regulator (IGR) pesticides in Cyphoderus javanus Borner (Collembola: Insecta) as potential biomarkers of soil pollution.

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Saha, Ipsita; Joy, V C

2016-02-01

The insect growth regulator (IGR) chemicals are considered as safe alternatives to synthetic organic pesticides, but only scant information are available on their possible impact on non-target and ecologically important soil insect fauna of croplands. Previous studies by the authors showed that recommended agricultural doses of IGRs buprofezin (Applaud 25SC at 250 g a.i. ha(-1)), flubendiamide (Takumi 20WG at 50 g a.i. ha(-1)) and novaluron (Rimon 10EC at 100 g a.i. ha(-1)) produced less mortality of adults of a non-target soil insect Cyphoderus javanus Borner (Collembola) but decreased major life history parameters namely moulting, fecundity and egg hatching success. This detritivorous microarthropod is very sensitive to soil characteristics and is ecologically relevant to the tropical soils. Present microcosm study showed strong biochemical impact of the above doses of IGRs on tissue nutrient levels and digestive enzyme activities in C. javanus within 7 days of exposure to treated sandy loam soil. The levels of tissue proteins, carbohydrates, lipids and free amino acids declined significantly and persistently in the specimens reared in IGR-treated soils than in the specimens of untreated soil. Similarly, α-amylase, cellulase and protease activities declined significantly in the specimens of IGR-treated soil. These nutritional scarcities would reduce metabolism, growth and reproduction in the affected insects. Therefore, the observed biochemical responses, especially the levels of tissue proteins, carbohydrates and α-amylase activity in C. javanus are early warning indices and potential biomarkers of soil pollution in croplands.

Environmental influences on the at-sea behaviour of a major consumer, Mirounga leonina, in a rapidly changing environment

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Trevor McIntyre

2014-11-01

Full Text Available Understanding the distribution and foraging ecology of major consumers within pelagic systems, specifically in relation to physical parameters, can be important for the management of bentho-pelagic systems undergoing rapid change associated with global climate change and other anthropogenic disturbances such as fishing (i.e., the Antarctic Peninsula and Scotia Sea. We tracked 11 adult male southern elephant seals (Mirounga leonina, during their five-month post-moult foraging migrations from King George Island (Isla 25 de Mayo, northern Antarctic Peninsula, using tags capable of recording and transmitting behavioural data and in situ temperature and salinity data. Seals foraged mostly within the Weddell–Scotia Confluence, while a few foraged along the western Antarctic Peninsula shelf of the Bellingshausen Sea. Mixed model outputs suggest that the at-sea behaviour of seals was associated with a number of environmental parameters, especially seafloor depth, sea-ice concentrations and the temperature structure of the water column. Seals increased dive bottom times and travelled at slower speeds in shallower areas and areas with increased sea-ice concentrations. Changes in dive depth and durations, as well as relative amount of time spent during the bottom phases of dives, were observed in relation to differences in overall temperature gradient, likely as a response to vertical changes in prey distribution associated with temperature stratification in the water column. Our results illustrate the likely complex influences of bathymetry, hydrography and sea ice on the behaviour of male southern elephant seals in a changing environment and highlight the need for region-specific approaches to studying environmental influences on behaviour.

Condition of larval (furcilia VI) and one year old juvenile Euphausia superba during the winter-spring transition in East Antarctica

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Virtue, Patti; Meyer, Bettina; Freier, Ulrich; Nichols, Peter D.; Jia, Zhongnan; King, Rob; Virtue, Jacob; Swadling, Kerrie M.; Meiners, Klaus M.; Kawaguchi, So

2016-09-01

Antarctic krill, Euphausia superba, is an important species in the Southern Ocean ecosystem. Information on krill condition during winter and early spring is slowly evolving with our enhanced ability to sample at this time of year. However, because of the limited spatial and temporal data, our understanding of fundamental biological parameters for krill during winter is limited. Our study assessed the condition of larval (furcilia VI) and one year old juvenile krill collected in East Antarctica (115°E-130°E and 64°S-66°S) from September to October 2012. Krill condition was assessed using morphometric, elemental and biochemical body composition, growth rates, oxygen uptake and lipid content and composition. Diet was assessed using fatty acid biomarkers analysed in the krill. The growth rate of larvae was 0.0038 mm day with an inter-moult period of 14 days. The average oxygen uptake of juvenile krill was 0.30±0.02 μl oxygen consumed per mg dry weight per hour. Although protein was not significantly different amongst the krill analysed, the lipid content of krill was highly variable ranging from 9% to 27% dry weight in juveniles and from 4% to 13% dry weight in larvae. Specific algal biomarkers, fatty acids ratios, levels of both long-chain (≥C20) monounsaturated fatty acids and bacterial fatty acids found in krill were indicative of the mixed nature of dietary sources and the opportunistic feeding capability of larval and juvenile krill at the end of winter.

Circumpolar variation in morphological characteristics of Greater White-fronted Geese Anser albifrons

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Ely, Craig R.; Fox, A.D.; Alisauskas, R.T.; Andreev, A.; Bromley, R.G.; Degtyarev, Andrei G.; Ebbinge, B.; Gurtovaya, E.N.; Kerbes, R.; Kondratyev, Alexander V.; Kostin, I.; Krechmar, A.V.; Litvin, K.E.; Miyabayashi, Y.; Moou, J.H.; Oates, R.M.; Orthmeyer, D.L.; Sabano, Yutaka; Simpson, S.G.; Solovieva, D.V.; Spindler, Michael A.; Syroechkovsky, Y.V.; Takekawa, John Y.; Walsh, A.

2005-01-01

Capsule: Greater White-fronted Geese show significant variation in body size from sampling locations throughout their circumpolar breeding range. Aims: To determine the degree of geographical variation in body size of Greater White-fronted Geese and identify factors contributing to any apparent patterns in variation. Methods: Structural measures of >3000 geese from 16 breeding areas throughout the Holarctic breeding range of the species were compared statistically. Results: Palearctic forms varied clinally, and increased in size from the smallest forms on the Kanin and Taimyr peninsulas in western Eurasia to the largest forms breeding in the Anadyr Lowlands of eastern Chukotka. Clinal variation was less apparent in the Nearctic, as both the smallest form in the Nearctic and the largest form overall (the Tule Goose) were from different breeding areas in Alaska. The Tule Goose was 25% larger than the smallest form. Birds from Greenland (A. a. flavirostris) were the second largest, although only slightly larger than geese from several North American populations. Body size was not correlated with breeding latitude but was positively correlated with temperature on the breeding grounds, breeding habitat, and migration distance. Body mass of Greater White-fronted Geese from all populations remained relatively constant during the period of wing moult. Morphological distinctness of eastern and western Palearctic forms concurs with earlier findings of complete range disjunction. Conclusions: Patterns of morphological variation in Greater White-fronted Geese across the Holarctic can be generally attributed to adaptation to variable breeding environments, migration requirements, and phylo-geographical histories. 

Early development and life cycle of Contracaecum multipapillatum s.l. from a brown pelican Pelecanus occidentalis in the Gulf of California, Mexico.

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Valles-Vega, Isabel; Molina-Fernández, Dolores; Benítez, Rocío; Hernández-Trujillo, Sergio; Adroher, Francisco Javier

2017-08-09

The initial developmental stages of Contracaecum multipapillatum (von Drasche, 1882) Lucker, 1941 sensu lato were studied using eggs obtained from the uteri of female nematodes (genetically identified) found in a brown pelican Pelecanus occidentalis from Bahía de La Paz (Gulf of California, Mexico). Optical microscopy revealed a smooth or slightly rough surface to the eggs. Egg dimensions were approximately 53 × 43 µm, although after the larvae had developed inside, egg size increased to 66 × 55 µm. Hatching and survival of the larvae were greater at 15°C than at 24°C, and increased salinity resulted in a slight increase in hatching but seemed to reduce survival at 24°C, but not at 15°C. The recently hatched larvae measured 261 × 16 µm within their sheath. When placed in culture medium, the larvae grew within their sheath, and a small percentage (~2%) exsheathed completely (314 × 19 µm). The larvae continued to grow and develop once they had exsheathed, attaining mean dimensions of 333 × 22 µm. Although they did not moult during culture, optical microscopy revealed a morphology typical of third-stage larvae. Finally, the genetic identity between the larval parasites collected from mullet Mugil curema and adult female parasites collected from the brown pelican suggests a life cycle of C. multipapillatum in which the mullet are involved as intermediate/paratenic hosts and the brown pelicans as final hosts in the geographical area of Bahía de La Paz.

Health assessment of free-ranging endangered Australian sea lion (Neophoca cinerea) pups: effect of haematophagous parasites on haematological parameters.

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Marcus, Alan D; Higgins, Damien P; Gray, Rachael

2015-06-01

Evaluation of the health status of free-ranging populations is important for understanding the impact of disease on individuals and on population demography and viability. In this study, haematological reference intervals were developed for free-ranging endangered Australian sea lion (Neophoca cinerea) pups within the context of endemic hookworm (Uncinaria sanguinis) infection and the effects of pathogen, host, and environment factors on the variability of haematological parameters were investigated. Uncinaria sanguinis was identified as an important agent of disease, with infection causing regenerative anaemia, hypoproteinaemia, and a predominantly lymphocytic-eosinophilic systemic inflammatory response. Conversely, the effects of sucking lice (Antarctophthirus microchir) were less apparent and infestation in pups appears unlikely to cause clinical impact. Overall, the effects of U. sanguinis, A. microchir, host factors (standard length, body condition, pup sex, moult status, and presence of lesions), and environment factors (capture-type and year of sampling) accounted for 26-65% of the total variance observed in haematological parameters. Importantly, this study demonstrated that anaemia in neonatal Australian sea lion pups is not solely a benign physiological response to host-environment changes, but largely reflects a significant pathological process. This impact of hookworm infection on pup health has potential implications for the development of foraging and diving behaviour, which would subsequently influence the independent survival of juveniles following weaning. The haematological reference intervals developed in this study can facilitate long-term health surveillance, which is critical for the early recognition of changes in disease impact and to inform conservation management. Copyright © 2015 Elsevier Inc. All rights reserved.

Reproductive potential and nesting effects of Osmia rufa (syn. bicornis female (Hymenoptera: Megachilidae

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Giejdasz Karol

2016-06-01

Full Text Available The red mason bee Osmia rufa is a solitary bee belonging to the family Megachilidae, and is prone to nest in aggregations. Each female builds a nest separately in pre-existing cavities such as holes in wood and walls or empty plant stems. This is done by successively setting the cells in a linear series. In this study, we elucidate the nesting behavior and the reproductive potential of a single O. rufa female. The reproductive potential of nesting females was evaluated after the offspring finished development. We observed that an individual female may colonize up to five nest tubes and build 5-34 cells in them (16 on an average. During the nesting time the number of cells decreased with the sequence of nest tubes colonized by one female, which built a maximum of 11 cells in the first occupied nest and 5 cells in the last (fifth nest. Our observations indicated that 40% of nesting females colonized one nest tube as compared to 7% colonizing five nest tubes. Furthermore, in subsequent nest tubes the number of cells with freshly emerged females gradually decreased which was the reverse with males. Thus, the sex ratio (proportion of male and female offspring may change during the nesting period. The female offspring predominated in the first two nesting tubes, while in the subsequent three tubes male offspring dominated. We also cataloged different causes of reduction in abundance of offspring in O. rufa females such as parasitization or problem associated with moulting.

BIOLOGICAL AND ULTRASTRUCTURAL STUDIES ON THE HAEMOCYTES OF F1 LARVAE OF THE GAMMA IRRADIATED GREAT WAX MOTH PUPAE GALLERIA MELLONELLA (L.) (LEPIDOPTERA : GAELLERIDAE)

International Nuclear Information System (INIS)

EL-KHOLY, E.M.S.; EL-NAGGAR, S.E.M.; ABD EL-AZIZ, N.M.

2008-01-01

The present study was carried out on the full grown male pupae of the greater wax moth, Galleria mellonella L., when irradiated with 100, 150, 300 and 400 Gray of gamma radiation. Two groups of newly moulted 4 th instar larvae were set up, each group consisted of 50 larvae. The first group was exposed in the pupal stage to 100 Gy and the second with 150 Gy then the larval haemolymph was collected. Also, a control group of 50 larvae (non-irradiated) was investigated. The morphological changes in the irradiated blood cells, as compared to the control, were examined using the transmission electron microscopy (TEM). Vacuolization of cytoplasm, disorganization and swelling of mitochondria were appeared. The biological effects of gamma irradiation of the parental male pupae on the reproduction of adult moths when treated males were mated with normal females (male line) and when normal males were mated with treated females (female line) were studied. The latent biological effects of four gamma doses (100, 150, 300 and 400 Gy) on the F1 generation showed that the average number of eggs per mated female, the percentage of egg hatch and the percent of mating were gradually reduced when the given gamma dose to male parents was increased at all treatments (male and female lines). The reduction in the fecundity and the percentage of egg hatch among female line pairings (females descendant of irradiated parental male pupae) was reduced than that among male line pairings (males descendant of irradiated parental male pupae) with increasing the gamma dose

Molecular cloning and characterization of glycogen synthase in Eriocheir sinensis.

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Li, Ran; Zhu, Li-Na; Ren, Li-Qi; Weng, Jie-Yang; Sun, Jin-Sheng

2017-12-01

Glycogen plays an important role in glucose and energy homeostasis at cellular and organismal levels. In glycogen synthesis, glycogen synthase (GS) is a rate-limiting enzyme catalysing the addition of α-1,4-linked glucose units from (UDP) 3 -glucose to a nascent glycogen chain using glycogenin (GN) as a primer. While studies on mammalian liver GS (GYS2) are numerous, enzymes from crustaceans, which also use glycogen and glucose as their main energy source, have received less attention. In the present study, we amplified full-length GS cDNA from Eriocheir sinensis. Tissue expression profiling revealed the highest expression of GS in the hepatopancreas. During moulting, GS expression and activity declined, and glycogen levels in the hepatopancreas were reduced. Recombinant GS was expressed in Escherichia coli Rosetta (DE3), and induction at 37°C or 16°C yielded EsGS in insoluble inclusion bodies (EsGS-I) or in soluble form (EsGS-S), respectively. Enzyme activity was measured in a cell-free system containing glucose-6-phosphate (G6P), and both forms possessed glycosyltransferase activity, but refolded EsGS-I was more active. Enzyme activity of both GS and EsGS-I in the hepatopancreas was optimum at 25°C, which is coincident with the optimum growth temperature of Chinese mitten crab, and higher (37°C) or lower (16°C) temperatures resulted in lower enzyme activity. Taken together, the results suggest that GS may be important for maintaining normal physiological functions such as growth and reproduction. Copyright © 2017 Elsevier Inc. All rights reserved.

Assessing mechanisms of toxicant response in the amphipod Melita plumulosa through transcriptomic profiling.

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Hook, Sharon E; Osborn, Hannah L; Spadaro, David A; Simpson, Stuart L

2014-01-01

This study describes the function of transcripts with altered abundance in the epibenthic amphipod, Melita plumulosa, following whole-sediment exposure to a series of common environmental contaminants. M. plumulosa were exposed for 48 h to sediments spiked and equilibrated with the following contaminants at concentrations predicted to cause sublethal effects to reproduction: porewater ammonia 30 mg L(-1); bifenthrin at 100 μg kg(-1); fipronil at 50 μg kg(-1); 0.6% diesel; 0.3% crude oil; 250 mg Cu kg(-1); 400 mg Ni kg(-1); and 400 mg Zn kg(-1). RNA was extracted and hybridized against a custom Agilent microarray developed for this species. Although the microarray represented a partial transcriptome and not all features on the array could be annotated, unique transcriptomic profiles were generated for each of the contaminant exposures. Hierarchical clustering grouped the expression profiles together by contaminant class, with copper and zinc, the petroleum products and nickel, and the pesticides each forming a distinct cluster. Many of the transcriptional changes observed were consistent with patterns previously described in other crustaceans. The changes in the transcriptome demonstrated that contaminant exposure caused changes in digestive function, growth and moulting, and the cytoskeleton following metal exposure, whereas exposure to petroleum products caused changes in carbohydrate metabolism, xenobiotic metabolism and hormone cycling. Functional analysis of these gene expression profiles can provide a better understanding of modes of toxic action and permits the prediction of mixture effects within contaminated ecosystems. Crown Copyright © 2013. Published by Elsevier B.V. All rights reserved.

Controls on gut phosphatisation: the trilobites from the Weeks Formation Lagerstätte (Cambrian; Utah.

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Rudy Lerosey-Aubril

Full Text Available Despite being internal organs, digestive structures are frequently preserved in Cambrian Lagerstätten. However, the reasons for their fossilisation and their biological implications remain to be thoroughly explored. This is particularly true with arthropods--typically the most diverse fossilised organisms in Cambrian ecosystems--where digestive structures represent an as-yet underexploited alternative to appendage morphology for inferences on their biology. Here we describe the phosphatised digestive structures of three trilobite species from the Cambrian Weeks Formation Lagerstätte (Utah. Their exquisite, three-dimensional preservation reveals unique details on trilobite internal anatomy, such as the position of the mouth and the absence of a differentiated crop. In addition, the presence of paired pygidial organs of an unknown function is reported for the first time. This exceptional material enables exploration of the relationships between gut phosphatisation and the biology of organisms. Indeed, soft-tissue preservation is unusual in these fossils as it is restricted to the digestive structures, which indicates that the gut played a central role in its own phosphatisation. We hypothesize that the gut provided a microenvironment where special conditions could develop and harboured a source of phosphorus. The fact that gut phosphatization has almost exclusively been observed in arthropods could be explained by their uncommon ability to store ions (including phosphorous in their digestive tissues. However, in some specimens from the Weeks Formation, the phosphatisation extends to the entire digestive system, suggesting that trilobites might have had some biological particularities not observed in modern arthropods. We speculate that one of them might have been an increased capacity for ion storage in the gut tissues, related to the moulting of their heavily-mineralised carapace.

Uptake of cobalt-60 from sea water and from labelled food by the common shrimp Crangon erangon (L.)

International Nuclear Information System (INIS)

Weers, A.W. van

1975-01-01

The role of two different modes of uptake in the accumulation of 60 Co by the common shrimp (Crangon crangon (L.)) is the subject of the present study. The results show that accumulation of 60 Co from sea water is a slow process. The concentration factor for whole animals reached in one month was only about 13. Most of the activity accumulated from water appears to be associated with the exoskeleton. As a consequence, moulting has a pronounced effect on the uptake pattern of 60 Co and on the subsequent retention of the radionuclide by shrimps kept in non-radioactive sea water. After single feeding of shrimps with labelled mussel flesh, 60 Co is retained according to an exponential function with a short-lived and a long-lived component. The short-lived component has a mean biological half-life of 1.2 days and accounts for about 80% of the initial activity. About 20% of the initial activity is lost with a mean biological half-life of about 10 days. After repeated feeding of labelled mussel flesh the short-lived component in the 60 Co retention is virtually absent. Cobalt-60 taken up with food is localized mainly in the digestive gland and the concentration in the edible muscles from the abdomen is relatively small. It is concluded from the present study that direct uptake from sea water will play only a minor role in the accumulation of 60 Co in the internal organs of the shrimp. 60 Co released into the marine environment will be taken up by shrimps mainly from food. The results indicate a rapid turnover of 60 Co in shrimps. (author)

The silkworm Bombyx mori cuticular protein CPR55 gene is regulated by the transcription factor βFTZ-F1

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Md. Saheb Ali

2016-01-01

Full Text Available The insect cuticle is composed of various proteins and formed during the moult under a complex biological process that depends on the cross talk between hormone levels and gene expression. In the present study, we aimed to clarify the ecdysone-dependent temporal regulation mechanisms of cuticular proteins expression and the underlying control of Bombyx mori metamorphosis. The expression of CPR55 was observed from the W3 early stage and peaked at pupation when the ecdysteroid titre declined. CPR55 was induced by the ecdysone pulse, and their expression peaked at 24 h after transfer to a hormone free medium. Transcripts of CPR55 were neither observed after the 20E pulse treatment in the presence of cycloheximide nor after the addition of 20E in V4 wing discs. We analysed the upstream region of the CPR55 gene using a transient reporter assay with a gene gun system which identified only one βFTZ-F1 binding site important for cis-acting elements for the transcription activation of the luciferase reporter gene by an ecdysone pulse. Site-directed mutagenesis of this element in the context of the 589-bp promoter fragment drastically decreased the reporter activity. The nuclear protein bound to βFTZ-F1 sites was identified by an electrophoretic mobility shift assay suggesting that CPR55 expression was regulated by βFTZ-F1 through the ecdysone pulse. The results confirmed that transcription factor, BmβFTZ-F1, binds to the cis-regulatory elements in the promoter of the gene coding for cuticle protein, CPR55, and regulates its expression during B. mori metamorphosis.

Biology and predatory attributes of a diplogasterid nematode, Fictor composticola Khan et al., 2008

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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.

Experimental manipulation reveals a trade-off between weapons and testes.

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Somjee, U; Miller, C W; Tatarnic, N J; Simmons, L W

2018-01-01

Theory predicts a trade-off between sexually selected weapons used to secure mates and post-copulatory traits used to maximize fertilization success. However, individuals that have a greater capacity to acquire resources from the environment may invest more in both pre- and post-copulatory traits, and trade-offs may not be readily apparent. Here, we manipulate the phenotype of developing individuals to examine allocation trade-offs between weapons and testes in Mictis profana (Hemiptera: Coreidae), a species where the hind legs are sexually selected weapons used in contests over access to females. We experimentally prevented males from developing weapons by inducing them to autotomize their hind legs before the final moult to adulthood. We compared trait expression in this group to males where autotomy was induced in the mid-legs, which are presumably not under sexual selection to the same extent. We found males without weapons invested proportionally more in testes mass than those with their mid-legs removed. Males that developed to adulthood without weapons did not differ from the mid-leg removal group in other traits potentially under precopulatory sexual selection, other post-copulatory traits or naturally selected traits. In addition, a sample of adult males from the same population in the wild revealed a positive correlation between investment in testes and weapons. Our study presents a critical contribution to a growing body of literature suggesting the allocation of resources to pre- and post-copulatory sexual traits is influenced by a resource allocation trade-off and that this trade-off may only be revealed with experimental manipulation. © 2017 European Society For Evolutionary Biology. Journal of Evolutionary Biology © 2017 European Society For Evolutionary Biology.

The early larval development of the tropical reef lobster Enoplometopus antillensis Lütken (Astacidea, Enoplometopidae reared in the laboratory Desenvolvimento dos estágios iniciais da lagosta de recife tropical Enoplometopus antillensis Lütken (Astacidea, Enoplometopidae cultivada em laboratório

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Fernando A. Abrunhosa

2007-06-01

Full Text Available The early stages of the tropical reef lobster Enoplometopus antillensis Lütken, 1865 were described and illustrated in detail from specimens reared in the laboratory. Ovigerous females were captured in their habitat, at a depth of about 15 meters and transported to the laboratory. The larvae were reared in a recirculation water tank for approximately 15 days and then transferred to four 10 liters aquariums. The larvae were fed on Artemia sp. nauplii. Microalgae Dunaliella viridis was added daily to the culture. The larvae moulted seven times progressing through the zoea VIII. Megalopa stage was not achieved. The intermoulting period of each stage averaged from eight to 12 days. Morphological comparisons with previous reports are briefly discussed.Os estágios iniciais da lagosta tropical Enoplometopus antillensis Lütken, 1865 foram descritos e ilustrados a partir de espécimes cultivados em laboratório. Fêmeas ovígeras foram capturadas em seu habitat, na profundidade cerca de 15 metros e transportadas para o laboratório. As larvas foram cultivadas em tanques de água recirculante por aproximadamente 15 dias e, então transferidas para quatro aquários (capacidade 10 litros. As larvas foram alimentadas com náuplios de Artemia sp. recém eclodidos. A microalga Dunaliella viridis AUTOR foi diariamente adicionada no cultivo. As larvas mudaram sete vezes alcançando o zoea VIII. O estágio megalopa não foi obtido. O período de intermuda de cada estágio variou de cerca de oito a 12 dias. Comparações morfológicas com trabalhos anteriores são brevemente discutidas.

Sable Island: A heritage to preserve

Energy Technology Data Exchange (ETDEWEB)

Villeneuve, C.

1997-09-01

Sable Island is strategically located on the edge of the teeming fisheries of the Newfoundland Grand Banks and near one of the main sea routes between North America and Europe. It has been the bane of navigators from 1583 onward, with 250 ships running aground, the latest in 1947. Marine productivity around Sable Island is very high owing to the temperature differences between the currents and the adjacent underwater topography. Dolphins and whales abound in the area known as the `Gully`, and there are no fewer than 36 fish species present in the waters surrounding the Island. Approximately 35 per cent of the Island is covered by vegetation which is limited to species adapted to sandy soil containing little organic matter and few nutrients. Some plants, such as the American beachgrass, grow in dense colonies and help to stabilize the dunes. Bird diversity is limited to species adapted to open areas, ponds and the littoral. Some 324 species have been recorded on the Island, but only 25 are known to nest there. The Island is one of world`s most important breeding sites for grey seals where they can be observed in great numbers during mating, whelping and moulting season. Among the many introduced animals only the legendary horses of Sable Island remain to this day. Despite its remoteness and isolation, the Island faces many threats, one of the most worrysome being the erosion of the eastern extremity of the Island during severe winter storms. The Island benefits from its status as a Migratory Bird Sanctuary, and is legally protected under Sable Island Regulations of the Navigation Act.

Recombinational micro-evolution of functionally different metallothionein promoter alleles from Orchesella cincta

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van Straalen Nico M

2007-06-01

Full Text Available Abstract Background Metallothionein (mt transcription is elevated in heavy metal tolerant field populations of Orchesella cincta (Collembola. This suggests that natural selection acts on transcriptional regulation of mt in springtails at sites where cadmium (Cd levels in soil reach toxic values This study investigates the nature and the evolutionary origin of polymorphisms in the metallothionein promoter (pmt and their functional significance for mt expression. Results We sequenced approximately 1600 bp upstream the mt coding region by genome walking. Nine pmt alleles were discovered in NW-European populations. They differ in the number of some indels, consensus transcription factor binding sites and core promoter elements. Extensive recombination events between some of the alleles can be inferred from the alignment. A deviation from neutral expectations was detected in a cadmium tolerant population, pointing towards balancing selection on some promoter stretches. Luciferase constructs were made from the most abundant alleles, and responses to Cd, paraquat (oxidative stress inducer and moulting hormone were studied in cell lines. By using paraquat we were able to dissect the effect of oxidative stress from the Cd specific effect, and extensive differences in mt induction levels between these two stressors were observed. Conclusion The pmt alleles evolved by a number of recombination events, and exhibited differential inducibilities by Cd, paraquat and molting hormone. In a tolerant population from a metal contaminated site, promoter allele frequencies differed significantly from a reference site and nucleotide polymorphisms in some promoter stretches deviated from neutral expectations, revealing a signature of balancing selection. Our results suggest that the structural differences in the Orchesella cincta metallothionein promoter alleles contribute to the metallothionein -over-expresser phenotype in cadmium tolerant populations.

Rooting gene trees without outgroups: EP rooting.

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Sinsheimer, Janet S; Little, Roderick J A; Lake, James A

2012-01-01

Gene sequences are routinely used to determine the topologies of unrooted phylogenetic trees, but many of the most important questions in evolution require knowing both the topologies and the roots of trees. However, general algorithms for calculating rooted trees from gene and genomic sequences in the absence of gene paralogs are few. Using the principles of evolutionary parsimony (EP) (Lake JA. 1987a. A rate-independent technique for analysis of nucleic acid sequences: evolutionary parsimony. Mol Biol Evol. 4:167-181) and its extensions (Cavender, J. 1989. Mechanized derivation of linear invariants. Mol Biol Evol. 6:301-316; Nguyen T, Speed TP. 1992. A derivation of all linear invariants for a nonbalanced transversion model. J Mol Evol. 35:60-76), we explicitly enumerate all linear invariants that solely contain rooting information and derive algorithms for rooting gene trees directly from gene and genomic sequences. These new EP linear rooting invariants allow one to determine rooted trees, even in the complete absence of outgroups and gene paralogs. EP rooting invariants are explicitly derived for three taxon trees, and rules for their extension to four or more taxa are provided. The method is demonstrated using 18S ribosomal DNA to illustrate how the new animal phylogeny (Aguinaldo AMA et al. 1997. Evidence for a clade of nematodes, arthropods, and other moulting animals. Nature 387:489-493; Lake JA. 1990. Origin of the metazoa. Proc Natl Acad Sci USA 87:763-766) may be rooted directly from sequences, even when they are short and paralogs are unavailable. These results are consistent with the current root (Philippe H et al. 2011. Acoelomorph flatworms are deuterostomes related to Xenoturbella. Nature 470:255-260).

Native strains of Beauveria bassiana for the control of Rhipicephalus sanguineus sensu lato.

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Cafarchia, Claudia; Immediato, Davide; Iatta, Roberta; Ramos, Rafael Antonio Nascimento; Lia, Riccardo Paolo; Porretta, Daniele; Figueredo, Luciana Aguiar; Dantas-Torres, Filipe; Otranto, Domenico

2015-02-05

Rhipicephalus sanguineus sensu lato ticks are widespread worldwide due to their adaptability to survive under different environmental conditions. They may act as vectors of a wide range of pathogens to humans and animals and their control is based on the use of chemical products on dogs and in the environment. Alternative control strategies, such as the use of entomopathogenic fungi as bio-control agents have also been investigated. The ability of native strains of Beauveria bassiana sensu lato in causing mortality in different tick species (e.g., Amblyomma cajennense and Rhipicephalus microplus) has been demonstrated. However, limited studies have assessed the use of B. bassiana for the control of R. sanguineus s.l. and none of them have employed native strains of this fungus. Here we investigated the pathogenicity of a native strain of B. bassiana (CD1123) against all developmental stages of R. sanguineus s.l.. Batches of eggs, larvae, nymphs and adult ticks were immersed in a suspension of 10(7) conidia/ml of B. bassiana s.l., isolated from a R. sanguineus s.l. engorged female. All treatment and control groups were observed for 20 days, and the biological parameters (i.e., mortality, hatching, moulting percentage, pre-oviposition period, oviposition period and rate, eggs production efficiency, reproductive efficiency and fitness indexes) were assessed. The effect of the B. bassiana strain tested herein on eggs, larvae, nymphs and adults showed a significantly higher mortality than those of the control groups (p bassiana strain is highly virulent towards all life-cycle developmental stages of R. sanguineus s.l. and may be of potential interest as a biological control agent against these ticks.

Chemical induction in mangrove crab megalopae, Ucides cordatus (Ucididae): Do young recruits emit metamorphosis-triggering odours as do conspecific adults?

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Simith, Darlan de Jesus de Brito; Abrunhosa, Fernando Araújo; Diele, Karen

2013-10-01

In many brachyuran species, including the mangrove crab Ucides cordatus, water-soluble chemicals (odours) emitted by adult residents trigger metamorphosis of megalopae, probably facilitating habitat selection and settlement near conspecific crab population. New field findings revealed that early benthic crab stages co-inhabit burrows of both juveniles and adults of U. cordatus which raised the question whether megalopae are also stimulated by sexually immature juveniles. Therefore, we tested in an experimental laboratory study the hypothesis that small benthic recruits and older juveniles also emit metamorphosis-stimulating odours as do conspecific adult crabs. U. cordatus megalopae were cultivated in eight conspecific odour-treatments containing seawater previously conditioned with crabs of different carapace widths (CW 0.15-5.0 cm) and in a control treatment with filtered seawater not conditioned with crabs. In all odour-treatments, including those with small immature crabs, the percentage of metamorphosed larvae was significantly higher (≥74%) and the average development was shorter (15.8-19.3 days) than in the control group, where only 30% moulted after 25.6 ± 6.6 days of megalopal development. In addition, megalopae developed 2.7 days faster when exposed to odours from young and older juveniles compared to those larvae kept in contact with odours from conspecific adults. Our results clearly demonstrate that the emission of metamorphic odours in U. cordatus is independent of size/age or sexual maturity. The responsiveness of megalopae to chemicals emitted by resident crabs of varying ages should aid the natural recovery of U. cordatus populations in areas significantly affected by size-selective fishery where only large conspecific adults are harvested.

Detailed description of the Ócsa Bird Ringing Station, Hungary

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Csörgő Tibor

2016-12-01

Full Text Available The present paper acts as an introduction to a series that will describe the exploratory analyses of migration phenology and morphometrics of the most common passerine species at the Ócsa Bird Ringing Station. This station is situated in the Ócsa Landscape Protection Area that belongs to the Duna–Ipoly National Park, Hungary. The area is somewhat cooler and more humid than the surrounding agricultural fields and tree plantations, covered by a mosaic of diverse hygrophilous vegetation patches. Bird trapping is mostly based on Japanese mist-net lines crossing different plant communities. During the period of 1984–2015, a total of 422,862 birds were trapped and ringed here, while 202,739 local, 1,235 within country, and 443 foreign recaptures were also recorded. Each bird is characterized by the following data: location and time of capture, species, age, sex, scores of fat, pectoral muscle, wing tip abrasion, and moult, length of wing, 3rd primary, and tail, and body mass. After subjected to a rigorous quality check, digital data are deposited in the archive of the Hungarian Bird Ringing Centre, and the EURING data base. From time to time, other research projects also utilized the accessibility of wild birds captured here, thus collection of blood samples, ecto- and endoparasites was carried out at the station. The relatively long time span, large number of species and individuals, and the readily available environmental (weather, vegetation, etc. data makes the avian data collected here a suitable base for studies of various disciplines like capture methodology, habitat preferences, breeding, migration, and wintering, effects of weather and climate change, and epidemiology of viruses and parasites.

Salinity tolerance of northern Brazilian mangrove crab larvae, Ucides cordatus (Ocypodidae): Necessity for larval export?

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Diele, Karen; Simith, Darlan J. B.

2006-07-01

The life cycle of the semiterrestrial mangrove crab Ucides cordatus includes pelagic larvae that are released into estuarine waters during the wet season and who may thus encounter potentially stressful low and variable salinity conditions. The effect of salinity on the survival of the zoea larvae, the number of zoeal stages and the duration of development from hatching to megalopa was experimentally studied by rearing larvae from the Caeté estuary, Northern Brazil, in seven salinity treatments (0, 5, 10, 15, 20, 25, and 30). For a better interpretation of the laboratory results, estuarine salinities were measured over five consecutive years during the species' reproductive season. The survival of the zoea larvae varied significantly with salinity, while the number of stages and the duration of their development remained constant. Development to megalopa took 20.77 ± 1.57 days and comprised five zoeal stages with ZI and ZII being euryhaline and later stages stenohaline. The newly hatched larvae stayed alive for up to 6 days in freshwater (average 4.32 ± 0.82 days), but did not moult to the second zoeal stage. ZII larvae first occurred from salinity 5 onwards and later zoeal stages at all tested salinities ≥10. However, the larvae only survived to megalopa at salinities ≥15, with highest numbers at salinity 30 (72%) and lowest at 15 (16%). Lethal salinities ≤10 occurred frequently in the estuary during the reproductive season. This suggests a need for larval export to offshore and thus more saline waters to allow for significant larval survival and maintenance of viable populations of this commercially important species. A regional rather than local approach for management is suggested due to the likelihood of long distance larval dispersal by offshore currents.

Natural variation in gene expression in the early development of dauer larvae of Caenorhabditis elegans

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Barker Gary LA

2009-07-01

Full Text Available Abstract Background The free-living nematode Caenorhabditis elegans makes a developmental decision based on environmental conditions: larvae either arrest as dauer larva, or continue development into reproductive adults. There is natural variation among C. elegans lines in the sensitivity of this decision to environmental conditions; that is, there is variation in the phenotypic plasticity of dauer larva development. We hypothesised that these differences may be transcriptionally controlled in early stage larvae. We investigated this by microarray analysis of different C. elegans lines under different environmental conditions, specifically the presence and absence of dauer larva-inducing pheromone. Results There were substantial transcriptional differences between four C. elegans lines under the same environmental conditions. The expression of approximately 2,000 genes differed between genetically different lines, with each line showing a largely line-specific transcriptional profile. The expression of genes that are markers of larval moulting suggested that the lines may be developing at different rates. The expression of a total of 89 genes was putatively affected by dauer larva or non-dauer larva-inducing conditions. Among the upstream regions of these genes there was an over-representation of DAF-16-binding motifs. Conclusion Under the same environmental conditions genetically different lines of C. elegans had substantial transcriptional differences. This variation may be due to differences in the developmental rates of the lines. Different environmental conditions had a rather smaller effect on transcription. The preponderance of DAF-16-binding motifs upstream of these genes was consistent with these genes playing a key role in the decision between development into dauer or into non-dauer larvae. There was little overlap between the genes whose expression was affected by environmental conditions and previously identified loci involved in

Neuroendocrine disruption in the shore crab Carcinus maenas: Effects of serotonin and fluoxetine on chh- and mih-gene expression, glycaemia and ecdysteroid levels.

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Robert, Alexandrine; Monsinjon, Tiphaine; Delbecque, Jean-Paul; Olivier, Stéphanie; Poret, Agnès; Foll, Frank Le; Durand, Fabrice; Knigge, Thomas

2016-06-01

Serotonin, a highly conserved neurotransmitter, controls many biological functions in vertebrates, but also in invertebrates. Selective serotonin reuptake inhibitors (SSRIs), such as fluoxetine, are commonly used in human medication to ease depression by affecting serotonin levels. Their residues and metabolites can be detected in the aquatic environment and its biota. They may also alter serotonin levels in aquatic invertebrates, thereby perturbing physiological functions. To investigate whether such perturbations can indeed be expected, shore crabs (Carcinus maenas) were injected either with serotonin, fluoxetine or a combination of both. Dose-dependent effects of fluoxetine ranging from 250 to 750nM were investigated. Gene expression of crustacean hyperglycemic hormone (chh) as well as moult inhibiting hormone (mih) was assessed by RT-qPCR at 2h and 12h after injection. Glucose and ecdysteroid levels in the haemolymph were monitored in regular intervals until 12h. Serotonin led to a rapid increase of chh and mih expression. On the contrary, fluoxetine only affected chh and mih expression after several hours, but kept expression levels significantly elevated. Correspondingly, serotonin rapidly increased glycaemia, which returned to normal or below normal levels after 12h. Fluoxetine, however, resulted in a persistent low-level increase of glycaemia, notably during the period when negative feedback regulation reduced glycaemia in the serotonin treated animals. Ecdysteroid levels were significantly decreased by serotonin and fluoxetine, with the latter showing less pronounced and less rapid, but longer lasting effects. Impacts of fluoxetine on glycaemia and ecdysteroids were mostly observed at higher doses (500 and 750nM) and affected principally the response dynamics, but not the amplitude of glycaemia and ecdysteroid-levels. These results suggest that psychoactive drugs are able to disrupt neuroendocrine control in decapod crustaceans, as they interfere with the

Uptake and retention of 124Sb in the common mussel, shrimp and shore crab

International Nuclear Information System (INIS)

Weers, A.W. van

1981-01-01

The uptake of radioactive antimony from water and food by mussels, shrimps and shore crabs and the subsequent loss in non-radioactive sea water were studied with 124 Sb. The concentration factors of about 0.6 for mussels and 2.5 for shrimps, reached by direct uptake from sea water, remained considerably below stable-antimony concentration factors reported for these organisms. The loss of 124 Sb after uptake of the radionuclide by mussels during 19 and 32 days respectively, could be described by a loss from two compartments with different rates. The distribution of the radionuclide in the animals did not change during the retention period. Antimony-124 taken up from sea water by shrimps was largely accounted for by adsorption to the exoskeleton, as was shown by the effect of moulting on the time course of subsequent loss in non-radioactive sea water. Antimony-124 applied to freeze-dried mussel flesh that was fed to shrimps was lost according to a single exponential function. The mean biological half-life of 124 Sb elimination was about 10 days. Two components were shown to be present in the retention of 124 Sb in two groups of shore crabs, one of which was fed freeze-dried shrimps spiked with 124 Sb, while the second group received shrimps labelled by uptake of 124 Sb with food. The only significant difference between the two groups was a longer mean biological half-life of the short-lived component in the second group. In shrimps and crabs only a small fraction of 124 Sb taken up with food ends up in the exoskeleton. About 45% of retained activity in crabs was found in the digestive gland. (author)

MANAGEMENT STRATEGIES, YIELD AND POPULATION DEVELOPMENT OF THE NOBLE CRAYFISH ASTACUS ASTACUS IN LAKE STEINSFJORDEN

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SKURDAL J.

2002-07-01

Full Text Available Lake Steinsfjorden is the most important noble crayfish locality in Norway. The crayfish population has been monitored annually since 1979 including data on total trapping effort, yield and population composition before and after the catching season. The harvest has ranged from 0.7-4.7 kg.ha-1. The catch per trap night decreased prior to 1991 and the yield was reduced by some 50% over the years 1987-1992 as compared to 1979-1986. This was due to removal of small crayfish, high exploitation and the establishment of dense stands of Canadian pondweed (Elodea canadensis. Baited traps catch a large fraction of crayfish < 95 mm total length minimum size. These should according to the regulations immediately be released into the lake. However, it is apparent from the size composition that release of these small crayfish was rather incomplete. In 1983, trap mesh size was increased from 17.5 mm to 21 mm to reduce the fraction of undersized crayfish in the trap catches, yet no effects of this increased mesh size on crayfish size distribution were observed. The legal season has been reduced three times during the study period. In 1983, the closing date was changed from 31 December to 15 September. In 1989 the legal season was further reduced to two weeks and finally in 1995 to 10 days. This reduced total trap effort by 45%. The shorter season allow many crayfish to moult twice instead of once between seasons and the fraction of large crayfish has thus increased and so has the catch per trap night. Canadian pondweed has established dense annual stands and thus has made large parts of the shallow areas unsuitable for crayfish, causing an overall decrease in crayfish population size and production.

Effects of individual pre-fledging traits and environmental conditions on return patterns in juvenile king penguins.

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Saraux, Claire; Viblanc, Vincent A; Hanuise, Nicolas; Le Maho, Yvon; Le Bohec, Céline

2011-01-01

Despite the importance of early life stages in individuals' life history and population dynamics, very few studies have focused on the constraints to which these juvenile traits are subjected. Based on 10 years of automatic monitoring of over 2500 individuals, we present the first study on the effects of environmental conditions and individual pre-fledging traits on the post-fledging return of non-banded king penguins to their natal colony. Juvenile king penguins returned exclusively within one of the three austral summers following their departure. A key finding is that return rates (range 68-87%) were much higher than previously assumed for this species, importantly meaning that juvenile survival is very close to that of adults. Such high figures suggest little juvenile dispersal, and selection occurring mostly prior to fledging in king penguins. Pre-fledging conditions had a strong quadratic impact on juvenile return rates. As expected, cohorts reared under very unfavourable years (as inferred by the breeding success of the colony) exhibited low return rates but surprisingly, so did those fledged under very favourable conditions. Juvenile sojourns away from the colony were shorter under warm conditions and subsequent return rates higher, suggesting a positive effect of climate warming. The longer the post-fledging trip (1, 2 or 3 years), the earlier in the summer birds returned to their natal colony and the longer they stayed before leaving for the winter journey. The presence of juveniles in the colony was more than twice the duration required for moulting purposes, yet none attempted breeding in the year of their first return. Juvenile presence in the colony may be important for acquiring knowledge on the social and physical colonial environment and may play an important part in the learning process of mating behaviour. Further studies are required to investigate its potential implications on other life-history traits such as recruitment age.

Interspecific competition among the secondary hole-nesting birds under the conditions of large interannual fluctuations of spring temperatures in Karelia

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Khokhlova Tatyana

2014-11-01

Full Text Available Data on the reproduction of birds in bird boxes (n=167-196 in Karelia in consequent years with drastic changes in spring temperature were analysed: 1975 - extremely early and warm spring, 1976 - late and cold one, 1977 - with medium indices. The changes in fertility, reproductive success and the number of Great tit Parus major L. (77 nests, Pied Flycatcher Ficedula hypoleuca L. (171, Redstart Phoenicurus phoenicurus (L. (10 and Wryneck Jynx torquilla L.-(6 were estimated. It was shown, that under the unstable conditions of the North, competition can make a considerable contribution to the dynamics of the population characteristics of birds and serve as one of the significant elements of the mechanism of their number regulation. Its influence is enhanced due to the convergence of the time of the breeding start of wintering and migratory birds in a year with late spring. The result of that is the rise in the number of nests lost due to anxiety or ruined by competitors, and increasing proportion of recycled clutch smaller in size and late on terms. These contributed to the fall of population productivity, the growth of the necessary reproductive effort in a significant part of individuals as well as the increase in the proportion of late broods, changing plumage at late time. After the year with early spring the number of all secondary hole-nesting birds grew, but after that with late spring, it reduced. The most significant decline in the population (in 3 times was showed by Great tits – species with bicyclical reproduction. Because of the high percent of late second and repeated nests in 1976 the large number of individuals moulted at late time and under the extremely adverse conditions and it resulted in their increased mortality.

Gene transcription in Daphnia magna: effects of acute exposure to a carbamate insecticide and an acetanilide herbicide.

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Pereira, Joana Luísa; Hill, Christopher J; Sibly, Richard M; Bolshakov, Viacheslav N; Gonçalves, Fernando; Heckmann, Lars-Henrik; Callaghan, Amanda

2010-05-05

Daphnia magna is a key invertebrate in the freshwater environment and is used widely as a model in ecotoxicological measurements and risk assessment. Understanding the genomic responses of D. magna to chemical challenges will be of value to regulatory authorities worldwide. Here we exposed D. magna to the insecticide methomyl and the herbicide propanil to compare phenotypic effects with changes in mRNA expression levels. Both pesticides are found in drainage ditches and surface water bodies standing adjacent to crops. Methomyl, a carbamate insecticide widely used in agriculture, inhibits acetylcholinesterase, a key enzyme in nerve transmission. Propanil, an acetanilide herbicide, is used to control grass and broad-leaf weeds. The phenotypic effects of single doses of each chemical were evaluated using a standard immobilisation assay. Immobilisation was linked to global mRNA expression levels using the previously estimated 48h-EC(1)s, followed by hybridization to a cDNA microarray with more than 13,000 redundant cDNA clones representing >5000 unique genes. Following exposure to methomyl and propanil, differential expression was found for 624 and 551 cDNAs, respectively (one-way ANOVA with Bonferroni correction, Pmoulting (e.g., chitin-binding proteins, cuticular proteins) and protein biosynthesis (e.g., ribosomal proteins, transcription factors). Methomyl induced the transcription of genes involved in specific processes such as ion homeostasis and xenobiotic metabolism. Propanil highly promoted haemoglobin synthesis and up-regulated genes specifically related to defence mechanisms (e.g., innate immunity response systems) and neuronal pathways. Pesticide-specific toxic responses were found but there is little evidence for transcriptional

BIOLOGY AND CONTROL OF THE APPLE MEALYBUG PHENACOCCUS ACERIS (SIGNORET) IN BELGIUM.

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Bangels, E; Peusens, G; Bylemans, D; Belien, T

2014-01-01

Although in general very rare, some outbreaks of the apple mealybug Phenococcus aceris (Signoret) (Hemiptera: Pseudococcidae) were reported in the Belgian fruit growing area recently. This insect is known to be geographically widespread, to have a broad host range and to infest apple trees. Damage at harvest is considerable when sooty molds, a consequence of the pest's honeydew production, cover the fruits. Indirect damage of an infection is caused in cherry cultivation through transmission of the Little cherry virus (LChV2). Efficacy trials were executed in infested apple orchards in the Belgian fruit growing area and the life cycle of the pest on apple was studied more into detail. Apple mealybugs are univoltine, overwinter as 2nd instar nymphs inside a white cocoon on the tree (under the bark, in crevices) and leave their overwintering site in early spring (mid March). On sunny days the nymphs become active, move around and attach to start feeding (mid April). After a final moult into the adult form, females lay eggs in a cocoon-like white structure (from flowering on). Following hatching (end May), massive numbers of young nymphs spread out on the underside of the leaves (mid June) where they feed through suction. In order to manage this pest the efficacy of several plant protection products was tested in two infested apple orchards. Results indicated that mortality was high after an application of compounds belonging to the neonicotinoid insecticides. Different application timings and control strategies are possible, with active nymphs being the most vulnerable life stage. The observed degree of parasitation in our trial orchards also indicates a biological control contribution of parasitic wasps that should be taken into account. A decent IPM-strategy based on our results solved the problem in both apple orchards.

Nuclear receptors HR96 and ultraspiracle from the fall armyworm (Spodoptera frugiperda), developmental expression and induction by xenobiotics.

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Giraudo, Maeva; Audant, Pascaline; Feyereisen, René; Le Goff, Gaëlle

2013-05-01

The fall armyworm Spodoptera frugiperda is a major polyphagous pest in agriculture and little is known on how this insect can adapt to the diverse and potentially toxic plant allelochemicals that they ingest or to insecticides. To investigate the involvement of nuclear receptors in the response of S. frugiperda to its chemical environment, we cloned SfHR96, a nuclear receptor orthologous to the mammalian xenobiotic receptors, pregnane X receptor (PXR) and constitutive androstane receptor (CAR). We also cloned ultraspiracle (USP), the ortholog of retinoid X receptor (RXR) that serves as partner of dimerization of PXR and CAR. Cloning of SfUSP revealed the presence of two isoforms, SfUSP-1 and SfUSP-2 in this species, that differ in their N-terminal region. The expression of these receptors as well as the ecdysone receptor was studied during specific steps of development in different tissues. SfHR96 was constitutively expressed in larval midgut, fat body and Malpighian tubules throughout the last two instars and pupal stage, as well as in Sf9 cells. EcR and SfUSP-2 showed peaks of expression before larval moults and during metamorphosis, whereas SfUSP-1 was mainly expressed in the pre-pupal stage. Receptor induction was followed after exposure of larvae or cells to 11 chemical compounds. SfHR96 was not inducible by the tested compounds. EcR was significantly induced by the 20-hydroxyecdysone agonist, methoxyfenozide, and SfUSP showed an increase expression when exposed to the juvenile hormone analog, methoprene. The cloning of these nuclear receptors is a first step in understanding the important capacities of adaptation of this insect pest. Copyright © 2013 Elsevier Ltd. All rights reserved.

An implantable instrument for studying the long-term flight biology of migratory birds

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Spivey, Robin J., E-mail: r.spivey@bangor.ac.uk, E-mail: c.bishop@bangor.ac.uk; Bishop, Charles M., E-mail: r.spivey@bangor.ac.uk, E-mail: c.bishop@bangor.ac.uk [Department of Biological Sciences, Bangor University, Gwynedd LL57 2UW (United Kingdom)

2014-01-15

The design of an instrument deployed in a project studying the high altitude Himalayan migrations of bar-headed geese (Anser indicus) is described. The electronics of this archival datalogger measured 22 × 14 × 6.5 mm, weighed 3 g, was powered by a ½AA-sized battery weighing 10 g and housed in a transparent biocompatible tube sealed with titanium electrodes for electrocardiography (ECG). The combined weight of 32 g represented less than 2% of the typical bodyweight of the geese. The primary tasks of the instrument were to continuously record a digitised ECG signal for heart-rate determination and store 12-bit triaxial accelerations sampled at 100 Hz with 15% coverage over each 2 min period. Measurement of atmospheric pressure provided an indication of altitude and rate of ascent or descent during flight. Geomagnetic field readings allowed for latitude estimation. These parameters were logged twice per minute along with body temperature. Data were stored to a memory card of 8 GB capacity. Instruments were implanted in geese captured on Mongolian lakes during the breeding season when the birds are temporarily flightless due to moulting. The goal was to collect data over a ten month period, covering both southward and northward migrations. This imposed extreme constraints on the design's power consumption. Raw ECG can be post-processed to obtain heart-rate, allowing improved rejection of signal interference due to strenuous activity of locomotory muscles during flight. Accelerometry can be used to monitor wing-beat frequency and body kinematics, and since the geese continued to flap their wings continuously even during rather steep descents, act as a proxy for biomechanical power. The instrument enables detailed investigation of the challenges faced by the geese during these arduous migrations which typically involve flying at extreme altitudes through cold, low density air where oxygen availability is significantly reduced compared to sea level.

20-hydroxyecdysone enhances the expression of the chitinase 5 via Broad-Complex Zinc-Finger 4 during metamorphosis in silkworm, Bombyx mori.

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Zhang, X; Zheng, S

2017-04-01

Insect chitinases are hydrolytic enzymes required for the degradation of chitin. They are essential for insect moulting and metamorphosis. In this study, the regulation mechanism of a chitinase gene, Bombyx mori chitinase 5 (BmCHT5), was studied. Quantitative reverse transcription PCR (qRT-PCR) analysis showed that BmCHT5 was up-regulated during the larval-larval and larval-pupa transitions and notably induced by 20-hydroxyecdysone (20E). Analysis of the BmCHT5 promoter revealed the presence of one Bombyx mori Broad-Complex Zinc-Finger Isoform 4 (BR-C Z4), two BR-C Z2 and two ecdysone-induced protein 74A (E74A) cis-regulatory elements (CREs) that are related to 20E. qRT-PCR showed that the expression of both BmBR-C Z4 and BmBR-C Z2 during metamorphosis, and when induced by 20E, was anastomotic with the variations in BmCHT5 mRNA level. In contrast, BmE74A did not follow this trend. An electrophoretic mobility shift assay did not retrieve a binding partner for the two BR-C Z2 CREs in the BmN cell line nuclear extract, whereas BR-C Z4 CRE specifically bound to BmBR-C Z4. Besides, luciferase activity analysis confirmed that BmBR-C Z4 could enhance the activity of the BmCHT5 promoter with BR-C Z4 CRE and could not enhance the promoter activity by mutating BR-C Z4 CRE. Taken together, these data suggest that the transcription factor BmBR-C Z4 enhances the expression of BmCHT5 during metamorphosis. © 2016 The Royal Entomological Society.

Foraging strategy switch of a top marine predator according to seasonal resource differences

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Malcolm Daniel O'Toole

2015-04-01

Full Text Available The spatio-temporal variability in marine resources influences the foraging behaviour and success of top marine predators. However, little is known about the links between these animals and ocean productivity, specifically, how plankton density influences their foraging behaviour. Southern elephant seals (Mirounga leonina have two annual at-sea foraging trips: a two month post-breeding foraging trip (Nov – Jan that coincides with elevated summer productivity; and an eight month post-moulting foraging trip (Feb – Oct over winter, when productivity is low. Physical parameters are often used to describe seal habitat, whereas information about important biological parameters is lacking. We used electronic tags deployed on elephant seals during both trips to determine their movement and foraging behaviour. The tags also recorded light, which measured the bio-optical properties of the water column, the bulk of which is presumably influenced by phytoplankton. We investigated the relationship between plankton density and seal foraging behaviour; comparing trends between summer and winter trips. We found a positive relationship between plankton density and foraging behaviour, which did not vary seasonally. We propose that profitable concentrations of seal prey are more likely to coincide with planktonic aggregations, but we also acknowledge that trophic dynamics may shift in response to seasonal trends in productivity. Seal prey (mid-trophic level and plankton (lower-trophic level are expected to overlap in space and time during summer trips when peak phytoplankton blooms occur. In contrast, aggregated patches of lower trophic levels are likely to be more dispersed during winter trips when plankton density is considerably lower and heterogeneous. These results show that southern elephant seals are able to exploit prey resources in different ways throughout the year as demonstrated by the variation observed between seal foraging behaviour and trophic

Ecotoxicity of triphenyltin on the marine copepod Tigriopus japonicus at various biological organisations: from molecular to population-level effects.

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Yi, Andy Xianliang; Han, Jeonghoon; Lee, Jae-Seong; Leung, Kenneth M Y

2014-09-01

Triphenyltin compounds (TPTs), as effective biocides for different industrial and agricultural purposes, have been detected in coastal marine environments worldwide, in particular in Asian countries. However, little is known about their toxicity to marine organisms. This study comprehensively investigated the molecular, individual and population responses of the marine copepod, Tigriopus japonicus upon waterborne exposure to TPT chloride (TPTCl). Our results indicated that TPTCl was highly toxic to adult T. japonicus, with a 96-h LC50 concentration at 6.3 μg/L. As shown in a chronic full life-cycle test, T. japonicus exposed to 1.0 μg/L TPTCl exhibited a delay in development and a significant reduction of population growth, in terms of the intrinsic rate of increase (r m ). Based on the negative relationship between the r m and exposure concentration, a critical effect concentration was estimated at 1.6 μg/L TPTCl; at or above which population extinction could occur. At 0.1 μg/L TPTCl or above, the sex ratio of the second generation of the copepod was significantly altered and changed to a male-biased population. At molecular level, the inhibition of the transcriptional expression of glutathione S-transferase related genes might lead to dysfunction of detoxification, and the inhibition of retinoid X receptor mRNA expression implied an interruption of the growth and moulting process in T. japonicus. As the only gene that observed up-regulated in this study, the expression of heat shock protein 70 (hsp70) increased in a concentration-dependent manner, indicating its function in protecting the copepod from TPT-mediated oxidative stress. The study advances our understanding on the ecotoxicity of TPT, and provides some initial data on its toxic mechanisms in small crustaceans like copepods.

Controls on Gut Phosphatisation: The Trilobites from the Weeks Formation Lagerstätte (Cambrian; Utah)

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Lerosey-Aubril, Rudy; Hegna, Thomas A.; Kier, Carlo; Bonino, Enrico; Habersetzer, Jörg; Carré, Matthieu

2012-01-01

Despite being internal organs, digestive structures are frequently preserved in Cambrian Lagerstätten. However, the reasons for their fossilisation and their biological implications remain to be thoroughly explored. This is particularly true with arthropods – typically the most diverse fossilised organisms in Cambrian ecosystems – where digestive structures represent an as-yet underexploited alternative to appendage morphology for inferences on their biology. Here we describe the phosphatised digestive structures of three trilobite species from the Cambrian Weeks Formation Lagerstätte (Utah). Their exquisite, three-dimensional preservation reveals unique details on trilobite internal anatomy, such as the position of the mouth and the absence of a differentiated crop. In addition, the presence of paired pygidial organs of an unknown function is reported for the first time. This exceptional material enables exploration of the relationships between gut phosphatisation and the biology of organisms. Indeed, soft-tissue preservation is unusual in these fossils as it is restricted to the digestive structures, which indicates that the gut played a central role in its own phosphatisation. We hypothesize that the gut provided a microenvironment where special conditions could develop and harboured a source of phosphorus. The fact that gut phosphatization has almost exclusively been observed in arthropods could be explained by their uncommon ability to store ions (including phosphorous) in their digestive tissues. However, in some specimens from the Weeks Formation, the phosphatisation extends to the entire digestive system, suggesting that trilobites might have had some biological particularities not observed in modern arthropods. We speculate that one of them might have been an increased capacity for ion storage in the gut tissues, related to the moulting of their heavily-mineralised carapace. PMID:22431989

Physicochemical properties of the modeled structure of astacin metalloprotease moulting enzyme NAS-36 and mapping the druggable allosteric space of Heamonchus contortus, Brugia malayi and Ceanorhabditis elegans via molecular dynamics simulation.

Science.gov (United States)

Sharma, Om Prakash; Agrawal, Sonali; Kumar, M Suresh

2013-12-01

Nematodes represent the second largest phylum in the animal kingdom. It is the most abundant species (500,000) in the planet. It causes chronic, debilitating infections worldwide such as ascariasis, trichuriasis, hookworm, enterobiasis, strongyloidiasis, filariasis and trichinosis, among others. Molecular modeling tools can play an important role in the identification and structural investigation of molecular targets that can act as a vital candidate against filariasis. In this study, sequence analysis of NAS-36 from H. contortus (Heamonchus contortus), B. malayi (Brugia malayi) and C. elegans (Ceanorhabditis elegans) has been performed, in order to identify the conserved residues. Tertiary structure was developed for an insight into the molecular structure of the enzyme. Molecular Dynamics Simulation (MDS) studies have been carried out to analyze the stability and the physical properties of the proposed enzyme models in the H. contortus, B. malayi and C. elegans. Moreover, the drug binding sites have been mapped for inhibiting the function of NAS-36 enzyme. The molecular identity of this protease could eventually demonstrate how ex-sheathment is regulated, as well as provide a potential target of anthelmintics for the prevention of nematode infections.

The role of canine distemper virus and persistent organic pollutants in mortality patterns of Caspian seals (Pusa caspica).

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Wilson, Susan C; Eybatov, Tariel M; Amano, Masao; Jepson, Paul D; Goodman, Simon J

2014-01-01

Persistent organic pollutants are a concern for species occupying high trophic levels since they can cause immunosuppression and impair reproduction. Mass mortalities due to canine distemper virus (CDV) occurred in Caspian seals (Pusa caspica), in spring of 1997, 2000 and 2001, but the potential role of organochlorine exposure in these epizootics remains undetermined. Here we integrate Caspian seal mortality data spanning 1971-2008, with data on age, body condition, pathology and blubber organochlorine concentration for carcases stranded between 1997 and 2002. We test the hypothesis that summed PCB and DDT concentrations contributed to CDV associated mortality during epizootics. We show that age is the primary factor explaining variation in blubber organochlorine concentrations, and that organochlorine burden, age, sex, and body condition do not account for CDV infection status (positive/negative) of animals dying in epizootics. Most animals (57%, n = 67) had PCB concentrations below proposed thresholds for toxic effects in marine mammals (17 µg/g lipid weight), and only 3 of 67 animals had predicted TEQ values exceeding levels seen to be associated with immune suppression in harbour seals (200 pg/g lipid weight). Mean organonchlorine levels were higher in CDV-negative animals indicating that organochlorines did not contribute significantly to CDV mortality in epizootics. Mortality monitoring in Azerbaijan 1971-2008 revealed bi-annual stranding peaks in late spring, following the annual moult and during autumn migrations northwards. Mortality peaks comparable to epizootic years were also recorded in the 1970s-1980s, consistent with previous undocumented CDV outbreaks. Gompertz growth curves show that Caspian seals achieve an asymptotic standard body length of 126-129 cm (n = 111). Males may continue to grow slowly throughout life. Mortality during epizootics may exceed the potential biological removal level (PBR) for the population, but the low frequency of

The role of canine distemper virus and persistent organic pollutants in mortality patterns of Caspian seals (Pusa caspica.

Directory of Open Access Journals (Sweden)

Susan C Wilson

Full Text Available Persistent organic pollutants are a concern for species occupying high trophic levels since they can cause immunosuppression and impair reproduction. Mass mortalities due to canine distemper virus (CDV occurred in Caspian seals (Pusa caspica, in spring of 1997, 2000 and 2001, but the potential role of organochlorine exposure in these epizootics remains undetermined. Here we integrate Caspian seal mortality data spanning 1971-2008, with data on age, body condition, pathology and blubber organochlorine concentration for carcases stranded between 1997 and 2002. We test the hypothesis that summed PCB and DDT concentrations contributed to CDV associated mortality during epizootics. We show that age is the primary factor explaining variation in blubber organochlorine concentrations, and that organochlorine burden, age, sex, and body condition do not account for CDV infection status (positive/negative of animals dying in epizootics. Most animals (57%, n = 67 had PCB concentrations below proposed thresholds for toxic effects in marine mammals (17 µg/g lipid weight, and only 3 of 67 animals had predicted TEQ values exceeding levels seen to be associated with immune suppression in harbour seals (200 pg/g lipid weight. Mean organonchlorine levels were higher in CDV-negative animals indicating that organochlorines did not contribute significantly to CDV mortality in epizootics. Mortality monitoring in Azerbaijan 1971-2008 revealed bi-annual stranding peaks in late spring, following the annual moult and during autumn migrations northwards. Mortality peaks comparable to epizootic years were also recorded in the 1970s-1980s, consistent with previous undocumented CDV outbreaks. Gompertz growth curves show that Caspian seals achieve an asymptotic standard body length of 126-129 cm (n = 111. Males may continue to grow slowly throughout life. Mortality during epizootics may exceed the potential biological removal level (PBR for the population, but the low

Status of grey seals along mainland Europe from the Southwestern Baltic to France

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Tero Härkönen

2007-01-01

Full Text Available The grey seal was a common species along mainland Europe during the Stone Age (8,000-5,500 BC. Along the North Sea coast populations started to decline substantially during the 11th century as a result of excessive hunting. The last breeding populations disappeared in the 16th century in the Wadden Sea, and before 1900 in the Kattegat-Skagerrak and the Southwestern Baltic as a result of an extermination campaign. No regular pupping occurred along mainland Europe until the end of the 1970s, when a breeding colony was established near Amrum in the German Wadden Sea. Somewhat later, additional breeding sites were discovered near Terschelling in the Dutch Wadden Sea (1980, at Helgoland, and off Brittany in France. Tracking of movements indicate these seal groups to be linked to the larger populations in the UK. Numbers of grey seals in the recolonised areas have increased over the years, but in the Kattegat-Skagerrak stable numbersof about 25 individuals have been observed since the 1970s, whereas more than 100 grey seals are found in the Southwestern Baltic. In the southeastern North Sea, 120 grey seals occur during moult at Helgoland, 120 in the German and over 1,130 in the Dutch parts of the Wadden Sea in 2004. Along the southern Dutch and Belgian coasts small groups are regularly observed, but no colonies have yet been established. In the colonies off Brittany in France about 105 grey seals have been counted. Successful pupping has only been recorded 3 times in the Kattegat-Skagerrak over the past 30 years, and 2-4 pups are born annually in France and the Southwestern Baltic. The relative strongholds for breeding along the European continent are the Dutch Wadden Sea, where in 2003/2004 at least 150 pups were recorded, Amrum in the German Wadden Sea (23 pups and Helgoland (8 pups. Consequently, total numbers of counted grey seals from the Southwestern Baltic to France amounted to at least 1,600 in 2004, while about 190 pups were born in the area.

Successful long-term maintenance of Mansonella perstans in an in vitro culture system

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Abdel Jelil Njouendou

2017-11-01

Full Text Available Abstract Background Approximately 114 million people are infected with Mansonella perstans in large proportions of Africa. In contrast to other filariae that infect humans, M. perstans-infected individuals show no distinct pathology or specific clinical picture, indicating a well-tuned adaptation to the host. In addition, since M. perstans adult worms reside in serous cavities which are difficult to access, research has been hindered and there is a paucity of knowledge about the biology of M. perstans, especially the development of the different life stages as well as M. perstans-driven immune responses. Thus in this study, an in vitro culture system was developed which allows an in-depth analysis of M. perstans. Results Culicoides species were caught in Ediki (Kumba, Southwest Region within Cameroon following a blood meal on a microfilaremic donor that had 1500 microfilariae/ml of peripheral blood and kept in captivity for 12 days at 23 °C. In a pilot experiment, 15 infective larvae were obtained from the midges and co-cultured with a confluent monolayer of monkey kidney epithelial cells (LLC-MK2 in DMEM medium supplemented with 10% FBS for up to 77 days. The resulting survival rates of 33% revealed that the cell-conditioned medium was suitable for long-term maintenance of M. perstans worms. To confirm these preliminary observations, 249 infective larvae were cultured for 50 days and their development was monitored daily and microscopically graded for motility. In total, 170 (68.3% filariae survived and 124 (49.8% larvae moulted between days 21–30 to become L5 stage larvae which were motile and showed continuous vigorous movement. Conclusion We have established an in vitro culture system for the generation and long-term maintenance of viable M. perstans worms. This technique will be an important tool to study parasite biology and development, the role in host immunity, and might be helpful to discover novel treatment strategies against

Insight on trace element detoxification in the Black-tailed Godwit (Limosa limosa) through genetic, enzymatic and metallothionein analyses

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Lucia, Magali, E-mail: m.lucia33@laposte.net [Littoral, Environnement et Societes (LIENSs), UMR 7266 CNRS-Universite de La Rochelle, 2 rue Olympe de Gouges, 17000 La Rochelle (France); Bocher, Pierrick [Littoral, Environnement et Societes (LIENSs), UMR 7266 CNRS-Universite de La Rochelle, 2 rue Olympe de Gouges, 17000 La Rochelle (France); Cosson, Richard P. [Mer Molecules Sante (MMS), Universite de Nantes, EA 2663, 2 rue de la Houssiniere, BP 92208, 44322 Nantes Cedex 3 (France); Churlaud, Carine; Robin, Frederic; Bustamante, Paco [Littoral, Environnement et Societes (LIENSs), UMR 7266 CNRS-Universite de La Rochelle, 2 rue Olympe de Gouges, 17000 La Rochelle (France)

2012-04-15

Trace element concentrations (Ag, As, Cd, Co, Cr, Cu, Fe, Hg, Mn, Ni, Pb, Se, Zn) were investigated in the liver, kidneys, muscle and feathers of 31 black-tailed godwits (Limosa limosa) accidentally killed during catches by mist net in the Pertuis Charentais, Atlantic coast of France. Analyses of carbon and nitrogen stable isotope ratios were carried out in liver, muscle and feathers in order to elucidate dietary patterns and to determine whether differences in diet explained the variation in elemental uptake. This study also aimed to have a preliminary assessment of sub-lethal effects triggered by trace elements through the investigation of gene expressions by quantitative real-time PCR, antioxidant enzyme activities (catalase, superoxide dismutase, glutathione peroxidase), and metallothionein (MT) levels. The results showed that Cr and Ni concentrations in tissues of adults were lower than in juveniles in part because adults may have eliminated these trace elements through moulting. Except for Cd and Ni, trace element concentrations were negatively correlated to the body mass of godwits. Ag, As, Hg and Se concentrations were positively linked with the trophic position of birds. The diet could be considered as a fundamental route of exposure for these elements demonstrating therefore the qualitative linkage between dietary habits of godwits and their contaminant concentrations. Our results strongly suggest that even though trace element concentrations were mostly below toxicity threshold level, the elevated concentrations of As, Ag, Cd, Cu, Fe and Se may however trigger sub-lethal effects. Trace elements appear to enhance expression of genes involved in oxidative stress defence, which indicates the production of reactive oxygen species. Moreover, birds with the highest concentrations appeared to have an increased mitochondrial metabolism suggesting that the fight against trace element toxicity requires additional energetic needs notably to produce detoxification

Distribution and persistence of the anti sea-lice drug teflubenzuron in wild fauna and sediments around a salmon farm, following a standard treatment

International Nuclear Information System (INIS)

Samuelsen, Ole B.; Lunestad, Bjørn T.; Hannisdal, Rita; Bannister, Raymond; Olsen, Siri; Tjensvoll, Tore; Farestveit, Eva; Ervik, Arne

2015-01-01

The salmon louse (Lepeoptheirus salmonis) is a challenge in the farming of Atlantic salmon (Salmo salar). To treat an infestation, different insecticides are used like the orally administered chitin synthetase inhibitor teflubenzuron. The concentrations and distribution of teflubenzuron were measured in water, organic particles, marine sediment and biota caught in the vicinity of a fish farm following a standard medication. Low concentrations were found in water samples whereas the organic waste from the farm, collected by sediment traps had concentrations higher than the medicated feed. Most of the organic waste was distributed to the bottom close to the farm but organic particles containing teflubenzuron were collected 1100 m from the farm. The sediment under the farm consisted of 5 to 10% organic material and therefore the concentration of teflubenzuron was much lower than in the organic waste. Teflubenzuron was persistent in the sediment with a stipulated halflife of 170 days. Sediment consuming polychaetes had high but decreasing concentrations of teflubenzuron throughout the experimental period, reflecting the decrease of teflubenzuron in the sediment. During medication most wild fauna contained teflubenzuron residues and where polychaetes and saith had highest concentrations. Eight months later only polychaetes and some crustaceans contained drug residues. What dosages that induce mortality in various crustaceans following short or long-term exposure is not known but the results indicate that the concentrations in defined individuals of king crab, shrimp, squat lobster and Norway lobster were high enough shortly after medication to induce mortality if moulting was imminent. Considering food safety, saith and the brown meat of crustaceans contained at first sampling concentrations of teflubenzuron higher than the MRL-value set for Atlantic salmon. The concentrations were, however, moderate and the amount of saith fillet or brown meat of crustaceans to be

Insight on trace element detoxification in the Black-tailed Godwit (Limosa limosa) through genetic, enzymatic and metallothionein analyses

International Nuclear Information System (INIS)

Lucia, Magali; Bocher, Pierrick; Cosson, Richard P.; Churlaud, Carine; Robin, Frédéric; Bustamante, Paco

2012-01-01

Trace element concentrations (Ag, As, Cd, Co, Cr, Cu, Fe, Hg, Mn, Ni, Pb, Se, Zn) were investigated in the liver, kidneys, muscle and feathers of 31 black-tailed godwits (Limosa limosa) accidentally killed during catches by mist net in the Pertuis Charentais, Atlantic coast of France. Analyses of carbon and nitrogen stable isotope ratios were carried out in liver, muscle and feathers in order to elucidate dietary patterns and to determine whether differences in diet explained the variation in elemental uptake. This study also aimed to have a preliminary assessment of sub-lethal effects triggered by trace elements through the investigation of gene expressions by quantitative real-time PCR, antioxidant enzyme activities (catalase, superoxide dismutase, glutathione peroxidase), and metallothionein (MT) levels. The results showed that Cr and Ni concentrations in tissues of adults were lower than in juveniles in part because adults may have eliminated these trace elements through moulting. Except for Cd and Ni, trace element concentrations were negatively correlated to the body mass of godwits. Ag, As, Hg and Se concentrations were positively linked with the trophic position of birds. The diet could be considered as a fundamental route of exposure for these elements demonstrating therefore the qualitative linkage between dietary habits of godwits and their contaminant concentrations. Our results strongly suggest that even though trace element concentrations were mostly below toxicity threshold level, the elevated concentrations of As, Ag, Cd, Cu, Fe and Se may however trigger sub-lethal effects. Trace elements appear to enhance expression of genes involved in oxidative stress defence, which indicates the production of reactive oxygen species. Moreover, birds with the highest concentrations appeared to have an increased mitochondrial metabolism suggesting that the fight against trace element toxicity requires additional energetic needs notably to produce detoxification

Impact assessment of an off-shore wind park on sea ducks

International Nuclear Information System (INIS)

Guillemette, M.; Kyed Larsen, J.; Clausager, I.

1998-03-01

As part of the plan of the Danish government to expand off-shore wind energy production, The Ministry of Environment and Energy, in collaboration with ELSAM (an energy consortium), initiated a three-year study of the potential conflict between the Tunoe Knob off-shore wind park and aquatic birds in 1994-97. Danish coastal waters support very large, internationally important concentrations of moulting, migrating and wintering sea ducks which depend on shallow water areas as major feeding habitats. Denmark is committed, in relation to international conventions and EU directives, to protect and maintain these populations of aquatic birds and such shallow coastal areas are precisely the type of areas in which future wind parks are planned. Two general approaches were adopted for the investigation: the before-after-control-impact design (BACI) and After studies conducted around the wind park. The aim of the BACI studies was to compare bird abundance and distribution before and after the construction of the wind park and between the area presumably affected by the development and a control area. This was carried out on three spatial scales: (i) conducting aerial surveys in two large zones (about 5,000 ha), Tunoe Knob and Ringebjerg Sand, while controlling the total number of birds in Aarhus Bay (88,000 ha), (ii) conducting ground surveys of two areas of about 700-800 ha coverage at Tunoe Knob and Ringebjerg Sand, using the latter as a control area and (iii) within Tunoe using three sub areas (160-250 ha) as controls compared to the construction area. The after experiments were conducted around the wind park with the aim of controlling the confounding effect of food supply and to establish (a) the short-term possible effects of noise and rotor movements generated by the turbines on the distribution and abundance of sea ducks and (b) the long-term scaring effect of the wind park (the impact of revolving rotors and the presence of the standing towers). Finally, an

Distribution and persistence of the anti sea-lice drug teflubenzuron in wild fauna and sediments around a salmon farm, following a standard treatment

Energy Technology Data Exchange (ETDEWEB)

Samuelsen, Ole B. [Institute of Marine Research, P.O. Box 1870 Nordnes, N-5817 Bergen (Norway); Lunestad, Bjørn T.; Hannisdal, Rita [National Institute of Nutrition and Seafood Research, P.O. Box 2029 Nordnes, N-5817 Bergen (Norway); Bannister, Raymond; Olsen, Siri [Institute of Marine Research, P.O. Box 1870 Nordnes, N-5817 Bergen (Norway); Tjensvoll, Tore [National Institute of Nutrition and Seafood Research, P.O. Box 2029 Nordnes, N-5817 Bergen (Norway); Farestveit, Eva; Ervik, Arne [Institute of Marine Research, P.O. Box 1870 Nordnes, N-5817 Bergen (Norway)

2015-03-01

The salmon louse (Lepeoptheirus salmonis) is a challenge in the farming of Atlantic salmon (Salmo salar). To treat an infestation, different insecticides are used like the orally administered chitin synthetase inhibitor teflubenzuron. The concentrations and distribution of teflubenzuron were measured in water, organic particles, marine sediment and biota caught in the vicinity of a fish farm following a standard medication. Low concentrations were found in water samples whereas the organic waste from the farm, collected by sediment traps had concentrations higher than the medicated feed. Most of the organic waste was distributed to the bottom close to the farm but organic particles containing teflubenzuron were collected 1100 m from the farm. The sediment under the farm consisted of 5 to 10% organic material and therefore the concentration of teflubenzuron was much lower than in the organic waste. Teflubenzuron was persistent in the sediment with a stipulated halflife of 170 days. Sediment consuming polychaetes had high but decreasing concentrations of teflubenzuron throughout the experimental period, reflecting the decrease of teflubenzuron in the sediment. During medication most wild fauna contained teflubenzuron residues and where polychaetes and saith had highest concentrations. Eight months later only polychaetes and some crustaceans contained drug residues. What dosages that induce mortality in various crustaceans following short or long-term exposure is not known but the results indicate that the concentrations in defined individuals of king crab, shrimp, squat lobster and Norway lobster were high enough shortly after medication to induce mortality if moulting was imminent. Considering food safety, saith and the brown meat of crustaceans contained at first sampling concentrations of teflubenzuron higher than the MRL-value set for Atlantic salmon. The concentrations were, however, moderate and the amount of saith fillet or brown meat of crustaceans to be

Radioisotopes in Studies on the Ecology of Tick Vectors of Disease

Energy Technology Data Exchange (ETDEWEB)

Sonenshine, D. E. [Old Dominion College, Norfolk, VA (United States)

1968-06-15

This paper demonstrates the feasibility of mass rearing of radioisotope-tagged immature ticks by collecting the progeny of engorged females of three species inoculated with carbon-14 glucose or glycine prior to oviposition. The incorporation of radiochemicals internally into ticks reduces the chance of loss of the radioactive label when moulting occurs, or under natural conditions. Most treated ticks laid eggs. The amount of radioactivity in the progeny could be controlled by controlling the size of the dose administered to the parent ticks. However, differences in radioactivity in the progeny of treated ticks in relation to the day of oviposition were noted. This activity declined progressively through the ninth day. Differences were also noted in relation to the radiochemical used. Most of the carbon-14 glycine (79.0%]o) received by the engorged females remained in the parents, whereas most of the carbon-14 glucose (77.5 %) received was transferred to the progeny. Hatching of eggs labelled by this method was less than in untreated oviposits. Radiosensitivity in the eggs was also noted and was related to the size of the dose administered to the parent tick. No hatching occurred when the average radioactivity of the labelled eggs exceeded 637 counts/min per egg over background. Nevertheless, many highly radioactive eggs hatched, and larvae with counts as high as 510 counts/min per larva over background were observed. The biological characteristics of the tagged larvae were apparently unaffected by incorporation of radiochemicals into these individuals. The proportion of marked larvae which attached to hosts was similar to the proportion of unmarked larvae which attached. The duration of survival of fasting, radioisotope-tagged larvae, under laboratory conditions, was similar to the period of survival of nonradioactive larvae. No apparent loss in radioactivity in fasting larvae held for up to 70 days under laboratory conditions was detected. This demonstration of

High feather mercury concentrations in the wandering albatross are related to sex, breeding status and trophic ecology with no demographic consequences

Energy Technology Data Exchange (ETDEWEB)

Bustamante, Paco, E-mail: pbustama@univ-lr.fr [Littoral Environnement et Sociétés (LIENSs), UMR 7266 CNRS-Université de la Rochelle, 2 rue Olympe de Gouges, 17000 La Rochelle (France); Carravieri, Alice [Littoral Environnement et Sociétés (LIENSs), UMR 7266 CNRS-Université de la Rochelle, 2 rue Olympe de Gouges, 17000 La Rochelle (France); Centre d’Etudes Biologiques de Chizé (CEBC), UMR 7372 du Centre National de la Recherche Scientifique-Université de La Rochelle, 79360 Villiers-en-Bois (France); Goutte, Aurélie [Centre d’Etudes Biologiques de Chizé (CEBC), UMR 7372 du Centre National de la Recherche Scientifique-Université de La Rochelle, 79360 Villiers-en-Bois (France); École Pratique des Hautes Études (EPHE), SPL, UPMC Université Paris 06, UMR 7619 METIS, F-75005, 4 place Jussieu, Paris (France); Barbraud, Christophe; Delord, Karine; Chastel, Olivier; Weimerskirch, Henri; Cherel, Yves [Centre d’Etudes Biologiques de Chizé (CEBC), UMR 7372 du Centre National de la Recherche Scientifique-Université de La Rochelle, 79360 Villiers-en-Bois (France)

2016-01-15

Hg can affect physiology of seabirds and ultimately their demography, particularly if they are top consumers. In the present study, body feathers of >200 wandering albatrosses from Possession Island in the Crozet archipelago were used to explore the potential demographic effects of the long-term exposure to Hg on an apex predator. Variations of Hg with sex, age class, foraging habitat (inferred from δ{sup 13}C values), and feeding habits (inferred from δ{sup 15}N values) were examined as well as the influence of Hg on current breeding output, long-term fecundity and survival. Wandering albatrosses displayed among the highest Hg feather concentrations reported for seabirds, ranging from 5.9 to 95 µg g{sup −1}, as a consequence of their high trophic position (δ{sup 15}N values). These concentrations fall within the same range of those of other wandering albatross populations from subantarctic sites, suggesting that this species has similar exposure to Hg all around the Southern Ocean. In both immature and adult albatrosses, females had higher Hg concentrations than males (28 vs. 20 µg g{sup −1} dw on average, respectively), probably as a consequence of females foraging at lower latitudes than males (δ{sup 13}C values). Hg concentrations were higher in immature than in adult birds, and they remained fairly constant across a wide range of ages in adults. Such high levels in immature individuals question (i) the frequency of moult in young birds, (ii) the efficiency of Hg detoxification processes in immatures compared to adults, and (iii) importantly the potential detrimental effects of Hg in early life. Despite very high Hg concentrations in their feathers, neither effects on adults' breeding probability, hatching failure and fledgling failure, nor on adults' survival rate were detected, suggesting that long-term bioaccumulated Hg was not under a chemical form leading to deleterious effects on reproductive parameters in adult individuals

Effects of the vertically transmitted microsporidian Facilispora margolisi and the parasiticide emamectin benzoate on salmon lice (Lepeophtheirus salmonis).

Science.gov (United States)

Poley, Jordan D; Sutherland, Ben J G; Fast, Mark D; Koop, Ben F; Jones, Simon R M

2017-08-17

Microsporidia are highly specialized, parasitic fungi that infect a wide range of eukaryotic hosts from all major taxa. Infections cause a variety of damaging effects on host physiology from increased stress to death. The microsporidian Facilispora margolisi infects the Pacific salmon louse (Lepeophtheirus salmonis oncorhynchi), an economically and ecologically important ectoparasitic copepod that can impact wild and cultured salmonids. Vertical transmission of F. margolisi was demonstrated by using PCR and in situ hybridization to identify and localize microsporidia in female L. salmonis and their offspring. Spores and developmental structures of F. margolisi were identified in 77% of F 1 generation copepods derived from infected females while offspring from uninfected females all tested negative for the microsporidia. The transcriptomic response of the salmon louse to F. margolisi was profiled at both the copepodid larval stage and the pre-adult stage using microarray technology. Infected copepodids differentially expressed 577 transcripts related to stress, ATP generation and structural components of muscle and cuticle. The infection also impacted the response of the copepodid to the parasiticide emamectin benzoate (EMB) at a low dose of 1.0 ppb for 24 h. A set of 48 transcripts putatively involved in feeding and host immunomodulation were up to 8-fold underexpressed in the F. margolisi infected copepodids treated with EMB compared with controls or either stressor alone. Additionally, these infected lice treated with EMB also overexpressed 101 transcripts involved in stress resistance and signalling compared to the other groups. In contrast, infected pre-adult lice did not display a stress response, suggesting a decrease in microsporidian virulence associated with lice maturity. Furthermore, copepodid infectivity and moulting was not affected by the microsporidian infection. This study demonstrated that F. margolisi is transmitted vertically between salmon

Toxic and essential elements changed in black-legged kittiwakes (Rissa tridactyla) during their stay in an Arctic breeding area

Energy Technology Data Exchange (ETDEWEB)

Øverjordet, Ida Beathe, E-mail: ida.beathe.overjordet@sintef.no [Norwegian University of Science and Technology (NTNU), Department of Biology, N-7491 Trondheim (Norway); Kongsrud, Magnus Brunvoll [Norwegian University of Science and Technology (NTNU), Department of Biology, N-7491 Trondheim (Norway); Gabrielsen, Geir Wing [Norwegian Polar Institute, N-9296 Tromsø (Norway); Berg, Torunn [NTNU, Department of Chemistry, N-7491 Trondheim (Norway); Ruus, Anders [Norwegian Institute for Water Research (NIVA), N-0349 Oslo (Norway); Evenset, Anita [Akvaplan-niva, Fram Centre, N-9296 Tromsø (Norway); Faculty of Biosciences, Fisheries and Economics, UiT The Arctic University of Norway (Norway); Borgå, Katrine [Norwegian Institute for Water Research (NIVA), N-0349 Oslo (Norway); Department of Biosciences, University of Oslo (Norway); Christensen, Guttorm [Akvaplan-niva, Fram Centre, N-9296 Tromsø (Norway); Jenssen, Bjørn Munro [Norwegian University of Science and Technology (NTNU), Department of Biology, N-7491 Trondheim (Norway)

2015-01-01

Seasonal fluctuations in mercury (Hg), cadmium (Cd), zinc (Zn), copper (Cu) and selenium (Se) concentrations were studied in black-legged kittiwakes (Rissa tridactyla) from Kongsfjorden, Svalbard (79°57′N, 12°12′E). Element concentrations were determined in muscle and liver tissue in kittiwakes collected in May, July and October 2007. Stable isotopes of carbon (δ{sup 13}C) and nitrogen (δ{sup 15}N) were analysed in muscle tissue to calculate trophic position (TP) and examine the possible influence of carbon source on element accumulation. Metallothionein (MT) concentrations in liver, as well as Hg and Cd concentration in size-fractionated liver supernatant were determined to evaluate the association between elements and MT. Mercury concentrations declined from May through July to October in both tissues, while concentrations of Cd were similar in May and July and lower in October. A decline in TP between May and July, indicating a shift from fish-based diet towards an invertebrate-based diet explains the declining Hg concentration. The low Hg and Cd concentrations in October may be a result of an increased elimination, probably related to moulting. Selenium decreased in the same manner as Hg in liver and muscle, possibly related to the formation of Se–Hg complexes. Zinc and Cu did not fluctuate in muscle tissue, whereas hepatic Zn concentrations where highest in May. Hepatic Zn concentrations were higher in females compared to males in May, possibly related to egg production. Hepatic MT concentrations were lower in October compared to July, following the same trend as Hg and Cd. Cadmium was predominantly bound to the MT fraction of proteins in liver tissue, whereas Hg was associated with the larger proteins, indicating that MT was not sequestering Hg in the kittiwakes. - Highlights: • Seasonality of Cd and Hg is closely related to seasonal dietary changes. • Migration patterns influence the accumulation of Hg and Cd. • The seasonality of Se and Hg

High feather mercury concentrations in the wandering albatross are related to sex, breeding status and trophic ecology with no demographic consequences

International Nuclear Information System (INIS)

Bustamante, Paco; Carravieri, Alice; Goutte, Aurélie; Barbraud, Christophe; Delord, Karine; Chastel, Olivier; Weimerskirch, Henri; Cherel, Yves

2016-01-01

Hg can affect physiology of seabirds and ultimately their demography, particularly if they are top consumers. In the present study, body feathers of >200 wandering albatrosses from Possession Island in the Crozet archipelago were used to explore the potential demographic effects of the long-term exposure to Hg on an apex predator. Variations of Hg with sex, age class, foraging habitat (inferred from δ 13 C values), and feeding habits (inferred from δ 15 N values) were examined as well as the influence of Hg on current breeding output, long-term fecundity and survival. Wandering albatrosses displayed among the highest Hg feather concentrations reported for seabirds, ranging from 5.9 to 95 µg g −1 , as a consequence of their high trophic position (δ 15 N values). These concentrations fall within the same range of those of other wandering albatross populations from subantarctic sites, suggesting that this species has similar exposure to Hg all around the Southern Ocean. In both immature and adult albatrosses, females had higher Hg concentrations than males (28 vs. 20 µg g −1 dw on average, respectively), probably as a consequence of females foraging at lower latitudes than males (δ 13 C values). Hg concentrations were higher in immature than in adult birds, and they remained fairly constant across a wide range of ages in adults. Such high levels in immature individuals question (i) the frequency of moult in young birds, (ii) the efficiency of Hg detoxification processes in immatures compared to adults, and (iii) importantly the potential detrimental effects of Hg in early life. Despite very high Hg concentrations in their feathers, neither effects on adults' breeding probability, hatching failure and fledgling failure, nor on adults' survival rate were detected, suggesting that long-term bioaccumulated Hg was not under a chemical form leading to deleterious effects on reproductive parameters in adult individuals. - Highlights: • Immature

Delayed metamorphosis in decapod crustaceans: evidence and consequences Retraso de la metamorfosis en crustáceos decápodos: evidencias y consecuencias

Directory of Open Access Journals (Sweden)

PAULINA GEBAUER

2003-06-01

Full Text Available Most marine invertebrate species exhibit a complex life cycle including a planktonic larval phase and a benthic juvenile-adult phase. Metamorphosis and settlement are the links between these phases of development. In many species, metamorphosis is triggered by specific chemical and/or physical cues, mainly associated with the adult habitat. In the absence of such cues, competent larvae can delay their metamorphosis by a few days to several months. Most investigations on the delay of metamorphosis have been realised on sessile or sedentary species. In relation to mobile decapod crustaceans, the number of such studies is low, probably because the members of this group retain their mobility after metamorphosis, and hence, may depend less on enviromental cues for the induction of settlement and metamorphosis. Nevertheless, the larvae of some decapod species have been shown to depend on metamorphosis-stimulating cues. These include special types of substrates, physical or chemical traits of particular (e.g., estuarine water bodies, as well as odors from conspecific or congeneric adults. The capacity for delay is, in the decapod species studied so far, limited and may normally end with spontaneous metamorphosis. An extended time of larval development presents the advantage of enhancing the probability for locating a suitable habitat, but it may imply, as a disadvantage, a reduction of juvenile growth or survival and a prolonged development time preceding benthic life. This paper reviews the available evidence for delayed metamorphosis in decapod crustaceans, indentifed cues, the importance of larval age at the time of contact with a cue, and costs of delayed metamorphosis. Additionally, we propose new frontiers for future investigations on delayed metamorphosis in decapod crustaceans, including the molecular identification of chemical cues, the identification of the stage(s of the moulting cycle that is or are sensitive to such cues, the study of

Echoes from the past: Regional variations in recovery within a harbour seal population.

Directory of Open Access Journals (Sweden)

Sophie M J M Brasseur

Full Text Available Terrestrial and marine wildlife populations have been severely reduced by hunting, fishing and habitat destruction, especially in the last centuries. Although management regulations have led to the recovery of some populations, the underlying processes are not always well understood. This study uses a 40-year time series of counts of harbour seals (Phoca vitulina in the Wadden Sea to study these processes, and demonstrates the influence of historical regional differences in management regimes on the recovery of this population. While the Wadden Sea is considered one ecologically coupled zone, with a distinct harbour seal population, the area is divided into four geo-political regions i.e. the Netherlands, Lower Saxony including Hamburg, Schleswig-Holstein and Denmark. Gradually, seal hunting was banned between 1962 and 1977 in the different regions. Counts of moulting harbour seals and pup counts, obtained during aerial surveys between 1974 and 2014, show a population growth from approximately 4500 to 39,000 individuals. Population growth models were developed to assess if population growth differed between regions, taking into account two Phocine Distemper Virus (PDV epizootics, in 1988 and 2002 which seriously affected the population. After a slow start prior to the first epizootic, the overall population grew exponentially at rates close to assumed maximum rates of increase in a harbour seal population. Recently, growth slowed down, potentially indicative of approaching carrying capacity. Regional differences in growth rates were demonstrated, with the highest recovery in Netherlands after the first PDV epizootic (i.e. 17.9%, suggesting that growth was fuelled by migration from the other regions, where growth remained at or below the intrinsic growth rate (13%. The seals' distribution changed, and although the proportion of seals counted in the German regions declined, they remained by far the most important pupping region, with approximately

Echoes from the past: Regional variations in recovery within a harbour seal population.

Science.gov (United States)

Brasseur, Sophie M J M; Reijnders, Peter J H; Cremer, Jenny; Meesters, Erik; Kirkwood, Roger; Jensen, Lasse Fast; Jeβ, Armin; Galatius, Anders; Teilmann, Jonas; Aarts, Geert

2018-01-01

Terrestrial and marine wildlife populations have been severely reduced by hunting, fishing and habitat destruction, especially in the last centuries. Although management regulations have led to the recovery of some populations, the underlying processes are not always well understood. This study uses a 40-year time series of counts of harbour seals (Phoca vitulina) in the Wadden Sea to study these processes, and demonstrates the influence of historical regional differences in management regimes on the recovery of this population. While the Wadden Sea is considered one ecologically coupled zone, with a distinct harbour seal population, the area is divided into four geo-political regions i.e. the Netherlands, Lower Saxony including Hamburg, Schleswig-Holstein and Denmark. Gradually, seal hunting was banned between 1962 and 1977 in the different regions. Counts of moulting harbour seals and pup counts, obtained during aerial surveys between 1974 and 2014, show a population growth from approximately 4500 to 39,000 individuals. Population growth models were developed to assess if population growth differed between regions, taking into account two Phocine Distemper Virus (PDV) epizootics, in 1988 and 2002 which seriously affected the population. After a slow start prior to the first epizootic, the overall population grew exponentially at rates close to assumed maximum rates of increase in a harbour seal population. Recently, growth slowed down, potentially indicative of approaching carrying capacity. Regional differences in growth rates were demonstrated, with the highest recovery in Netherlands after the first PDV epizootic (i.e. 17.9%), suggesting that growth was fuelled by migration from the other regions, where growth remained at or below the intrinsic growth rate (13%). The seals' distribution changed, and although the proportion of seals counted in the German regions declined, they remained by far the most important pupping region, with approximately 70% of all pups

Nephrops norvegicus (L.: Comparative biology and fishery in the Mediterranean Sea. Introduction, conclusions and recommendations

Directory of Open Access Journals (Sweden)

Francesc Sardà

1998-12-01

Full Text Available The project, financed by the Directorate General XIV of the EC, has undertaken a comparative study on the biology and fisheries techniques of the Norway lobster in Mediterranean member states and adjoining Atlantic areas. The ultimate goal of the project has been to assess the conditions for a global regulation in the area and determine possible differences among exploited stocks. The areas selected are characterised by their importance in Norway lobster catch. The overall duration of the project has been three years. Sampling was concentrated in the first two years. Data analysis was conducted during the second and third years (1993-1995. The countries (areas involved in the study, together with their target areas, were: Portugal (south coast of Algarve, Spain (Alboran and Catalan Seas, Italy (Ligurian, Tyrrhenian and Adriatic Seas and Greece (Gulf of Euboikos. In order to make results perfectly comparable, each scientific subject has been developed by a specialised team using a unified and standardised methodology. From the biological standpoint, Norway lobster growth, reproduction, moult and feeding have been compared. Special studies on distribution and genetics have been also conducted. In the fisheries context, a comparison of fishing techniques has been undertaken. The fisheries studies have been complemented with reconstruction of virgin populations, comparison of yield per recruit, sensitivity analysis and transition analysis. Selectivity issues have been object of specific analyses. As a result of these studies, it is evident that Norway lobster populations in the Mediterranean follow a common life-cycle model. The differences among areas reported in this project respond to environmental variation and differential fishing pressure in each area. All populations are exploited near its carrying limit, although overexploitation is unlikely at this stage. However we identified varying levels of exploitation according to study areas: The

Protein metabolism in marine animals: the underlying mechanism of growth.

Science.gov (United States)

Fraser, Keiron P P; Rogers, Alex D

2007-01-01

Growth is a fundamental process within all marine organisms. In soft tissues, growth is primarily achieved by the synthesis and retention of proteins as protein growth. The protein pool (all the protein within the organism) is highly dynamic, with proteins constantly entering the pool via protein synthesis or being removed from the pool via protein degradation. Any net change in the size of the protein pool, positive or negative, is termed protein growth. The three inter-related processes of protein synthesis, degradation and growth are together termed protein metabolism. Measurement of protein metabolism is vital in helping us understand how biotic and abiotic factors affect growth and growth efficiency in marine animals. Recently, the developing fields of transcriptomics and proteomics have started to offer us a means of greatly increasing our knowledge of the underlying molecular control of protein metabolism. Transcriptomics may also allow us to detect subtle changes in gene expression associated with protein synthesis and degradation, which cannot be detected using classical methods. A large literature exists on protein metabolism in animals; however, this chapter concentrates on what we know of marine ectotherms; data from non-marine ectotherms and endotherms are only discussed when the data are of particular relevance. We first consider the techniques available to measure protein metabolism, their problems and what validation is required. Protein metabolism in marine organisms is highly sensitive to a wide variety of factors, including temperature, pollution, seasonality, nutrition, developmental stage, genetics, sexual maturation and moulting. We examine how these abiotic and biotic factors affect protein metabolism at the level of whole-animal (adult and larval), tissue and cellular protein metabolism. Available gene expression data, which help us understand the underlying control of protein metabolism, are also discussed. As protein metabolism appears to

Insights into the CuO nanoparticle ecotoxicity with suitable marine model species.

Science.gov (United States)

Rotini, A; Gallo, A; Parlapiano, I; Berducci, M T; Boni, R; Tosti, E; Prato, E; Maggi, C; Cicero, A M; Migliore, L; Manfra, L

2018-01-01

Metal oxide nanoparticles, among them copper oxide nanoparticles (CuO NPs), are widely used in different applications (e.g. batteries, gas sensors, superconductors, plastics and metallic coatings), increasing their potential release in the environment. In aquatic matrix, the behavior of CuO NPs may strongly change, depending on their surface charge and some physical-chemical characteristics of the medium (e.g. ionic strength, salinity, pH and natural organic matter content). Ecotoxicity of CuO NPs to aquatic organisms was mainly studied on freshwater species, few tests being performed on marine biota. The aim of this study was to assess the toxicity of CuO NPs on suitable indicator species, belonging to the ecologically relevant level of consumers. The selected bioassays use reference protocols to identify Effect/Lethal Concentrations (E(L)C), by assessing lethal and sub-lethal endpoints. Mortality tests were performed on rotifer (Brachionus plicatilis), shrimp (Artemia franciscana) and copepod (Tigriopus fulvus). While moult release failure and fertilization rate were studied, as sub-lethal endpoints, on T. fulvus and sea urchin (Paracentrotus lividus), respectively. The size distribution and sedimentation rates of CuO NPs, together with the copper dissolution, were also analyzed in the exposure media. The CuO NP ecotoxicity assessment showed a concentration-dependent response for all species, indicating similar mortality for B. plicatilis (48hLC 50 = 16.94 ± 2.68mg/l) and T. fulvus (96hLC 50 = 12.35 ± 0.48mg/l), followed by A. franciscana (48hLC 50 = 64.55 ± 3.54mg/l). Comparable EC 50 values were also obtained for the sub-lethal endpoints in P. lividus (EC 50 = 2.28 ± 0.06mg/l) and T. fulvus (EC 50 = 2.38 ± 0.20mg/l). Copper salts showed higher toxicity than CuO NPs for all species, with common sensitivity trend as follows: P. lividus ≥ T. fulvus (sublethal endpoint) ≥ B. plicatilis >T. fulvus (lethal endpoint) >A. franciscana. CuO NP micrometric

Comparación ontogénica de la frecuencia de muda en Rhinella marina (Anura, Bufonidae Ontogenetic comparison of the molting frequency in Rhinella marina (Anura: Bufonidae

Directory of Open Access Journals (Sweden)

Teófila M. Triana

2013-03-01

hours (Chi-square, χ2=7.891, p=0.019, particularly in the two groups of juveniles, who moulted mostly at night, as adults did not show any clear difference. It is possible that the highest molting frequency in juveniles may be related to their ontogenetic status, with a smaller size and higher metabolic and developmental rate.

Are population dynamics of shorebirds affected by El Niño/Southern Oscillation (ENSO) while on their non-breeding grounds in Ecuador?

Science.gov (United States)

O'Hara, Patrick D.; Haase, Ben J. M.; Elner, Robert W.; Smith, Barry D.; Kenyon, Jamie K.

2007-08-01

Declines in avian populations are a global concern, particularly for species that migrate between Arctic-temperate and tropical locations. Long-term population studies offer opportunities to detect and document ecological effects attributable to long-term climatic cycles such as the El Niño/Southern Oscillation (ENSO). In this study, we report possible population-level effects of such climatic cycles on shorebird species that use two non-breeding season sites in Ecuador (Santa Elena peninsula area, near La Libertad). During our 9-year study period (1991/1992-1999/2000), there was a particularly strong ENSO warm phase event during 1997/1998. Population trend data for three species of shorebird, Western Sandpipers ( Calidris mauri), Semipalmated Sandpipers ( C. pusilla), and Least Sandpipers ( C. minutilla), indicated abundances generally declined during the 1990s, but there was an increase in the proportion of first-year birds and their abundance in the years following the 1997/1998 ENSO warm phase. There was some support for variation in apparent survivorship associated with the onset of the ENSO warm phase event in our population models, based on capture-mark-recapture data. Following the 1997/1998 ENSO event onset, individuals for all three species were significantly lighter during the non-breeding season ( F1,3789 = 6.6, p = 0.01). Least-squares mean mass (controlling for size, sex and day of capture) for first-year birds dropped significantly more than for adults following ENSO (first-year mass loss = 0.69 ± 0.12 g; adult mass loss = 0.34 ± 0.11 g, F1,3789 = 5.31, p = 0.021), and least-squares mean mass dropped most during the period when sandpipers prepare for northward migration by gaining mass and moulting into breeding plumage. Least Sandpipers may have declined the most in mean mass following ENSO (0.76 ± 0.19 g), whereas Semipalmated Sandpipers were 0.52 ± 0.12 g lighter, and Western Sandpipers 0.40 ± 0.13 g lighter, but overall variation among

Under the sea ice: Exploring the relationship between sea ice and the foraging behaviour of southern elephant seals in East Antarctica

Science.gov (United States)

Labrousse, Sara; Sallée, Jean-Baptiste; Fraser, Alexander D.; Massom, Robert A.; Reid, Phillip; Sumner, Michael; Guinet, Christophe; Harcourt, Robert; McMahon, Clive; Bailleul, Frédéric; Hindell, Mark A.; Charrassin, Jean-Benoit

2017-08-01

Investigating ecological relationships between predators and their environment is essential to understand the response of marine ecosystems to climate variability and change. This is particularly true in polar regions, where sea ice (a sensitive climate variable) plays a crucial yet highly dynamic and variable role in how it influences the whole marine ecosystem, from phytoplankton to top predators. For mesopredators such as seals, sea ice both supports a rich (under-ice) food resource, access to which depends on local to regional coverage and conditions. Here, we investigate sex-specific relationships between the foraging strategies of southern elephant seals (Mirounga leonina) in winter and spatio-temporal variability in sea ice concentration (SIC) and coverage in East Antarctica. We satellite-tracked 46 individuals undertaking post-moult trips in winter from Kerguelen Islands to the peri-Antarctic shelf between 2004 and 2014. These data indicate distinct general patterns of sea ice usage: while females tended to follow the sea ice edge as it extended northward, the males remained on the continental shelf despite increasing sea ice. Seal hunting time, a proxy of foraging activity inferred from the diving behaviour, was longer for females in late autumn in the outer part of the pack ice, ∼150-370 km south of the ice edge. Within persistent regions of compact sea ice, females had a longer foraging activity (i) in the highest sea ice concentration at their position, but (ii) their foraging activity was longer when there were more patches of low concentration sea ice around their position (either in time or in space; 30 days & 50 km). The high spatio-temporal variability of sea ice around female positions is probably a key factor allowing them to exploit these concentrated patches. Despite lack of information on prey availability, females may exploit mesopelagic finfishes and squids that concentrate near the ice-water interface or within the water column (from

Population structure and sexual maturity of the calico box crab Hepatus epheliticus Linnaeus (Brachyura, Hepatidae from Yucatan Peninsula, Mexico Estructura poblacional y madurez sexual en el cangrejo caja moteado Hepatus epheliticus Linnaeus (Brachyura, Hepatidae procedente de la Península del Yucatán, México

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Patricio Hernáez

2012-07-01

Full Text Available The calico box crab Hepatus epheliticus is an abundant species from shallow and continental shelf waters of the Atlantic coast of USA and Mexico. Information about population structure and sexual maturity is absent, even though this crab is caught to be used as bait for the octopus fishery in the Campeche Bank, Mexico. In order to achieve such information, a total of 768 individuals were collected from January to March 2010 through baited traps installed in the Yucatan Peninsula, Mexico. Our results showed that sex ratio is biased towards more males than females (1:0.55, contradicting to that reported in other brachyuran crabs. The absence of ovigerous females suggests that they did not enter into the traps during embryogenesis. Males reached a larger maximum size than females (64.0 ± 6.15 and 58.4 ± 5.60 mm carapace width, respectively. The general scheme of growth being positive allometric throughout ontogeny of both sexes. Males presented a transition phase from juveniles to adult corresponding to the puberty moult. The estimation of the onset of functional sexual maturity revealed a steady situation for the population, with 21.5 and 13.8% of males and females, respectively, morphologically immature at the time of catch. This study constitutes the first report on population structure and sexual maturity in a population of the calico box crab H. epheliticus.El cangrejo caja moteado Hepatus epheliticus es un abundante braquiuro perteneciente a la familia Hepatidae, distribuido desde aguas someras hasta la plataforma continental en la costa atlántica de Estados Unidos y México. La información sobre su demografía poblacional y madurez sexual es actualmente inexistente, aun cuando esta especie es intensamente capturada como carnada en la pesquería del pulpo del estado de Campeche, México. Entre enero y marzo de 2010, se colectaron 768 especímenes usando trampas instaladas en la Península de Yucatán, México. Los resultados mostraron una

A revision of dragon millipedes I: genus Desmoxytes Chamberlin, 1923, with the description of eight new species (Diplopoda, Polydesmida, Paradoxosomatidae

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Ruttapon Srisonchai

2018-05-01

, comb. n., H. simplipodus (Liu, Golovatch & Tian, 2016, comb. n., H. specialis (Nguyen, Golovatch & Anichkin, 2005, comb. n., H. spectabilis (Attems, 1937, comb. n., H. spinitergus (Liu, Golovatch & Tian, 2016, comb. n., H. spinissimus (Golovatch, Li, Liu & Geoffroy, 2012, comb. n. and H. variabilis (Liu, Golovatch & Tian, 2016, comb. n. Desmoxytes s.s. includes the following species: D. breviverpa Srisonchai, Enghoff & Panha, 2016; D. cervina (Pocock,1895; D. delfae (Jeekel, 1964; D. des Srisonchai, Enghoff & Panha, 2016; D. pinnasquali Srisonchai, Enghoff & Panha, 2016; D. planata (Pocock, 1895; D. purpurosea Enghoff, Sutcharit & Panha, 2007; D. takensis Srisonchai, Enghoff & Panha, 2016; D. taurina (Pocock, 1895; D. terae (Jeekel, 1964, all of which are re-described based mainly on type material. Two new synonyms are proposed: Desmoxytes pterygota Golovatch & Enghoff, 1994, syn. n. (= Desmoxytes cervina (Pocock, 1895, Desmoxytes rubra Golovatch & Enghoff, 1994, syn. n. (= Desmoxytes delfae (Jeekel, 1964. Six new species are described from Thailand: D. aurata Srisonchai, Enghoff & Panha, sp. n., D. corythosaurus Srisonchai, Enghoff & Panha, sp. n., D. euros Srisonchai, Enghoff & Panha, sp. n., D. flabella Srisonchai, Enghoff & Panha, sp. n., D. golovatchi Srisonchai, Enghoff & Panha, sp. n., D. octoconigera Srisonchai, Enghoff & Panha, sp. n., as well as one from Malaysia: D. perakensis Srisonchai, Enghoff & Panha, sp. n., and one from Myanmar: D. waepyanensis Srisonchai, Enghoff & Panha, sp. n. The species can mostly be easily distinguished by gonopod structure in combination with other external characters; some cases of particularly similar congeners are discussed. All species of Desmoxytes s.s. seem to be endemic to continental Southeast Asia (except the ‘tramp’ species D. planata. Some biological observations (relationship with mites, moulting are recorded for the first time. Complete illustrations of external morphological characters, an identification key

Abundancia relativa de Amblyomma spp. (Acari: Ixodidae en bovinos (Bos taurus y B. indicus de Costa Rica

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V. Alvarez

2003-06-01

. The study compiled meteorological information for some farms located in the experiment, showing that the most fluctuant variable is rainfall. The most important Amblyomma species found was A. cajennense. Amblyomma nymphs were found only from January to May, which coincides with the lower humidity season in the rain seasonality area; as for it is expected only one generation per year. In the lab work Amblyomma nymphs are kept to measure the moulting season and the surviving time under controlled conditions, but no major differences were found between both sexes. The surviving periods show that it is not possible to do a grazing land handling, in order to control this genus species. Adults of the genus Amblyomma are present through all the year, not showing any specific preference for a season. The research divided the investigation areas in rain seasonality and not-seasonality systems. The highest amount of Amblyomma is found given in the rain seasonality system or of Pacific influence. A. maculatum is present only in the EZ of Tropical Humid Forest transition to pre-montainous. Likewise, Ixodes boliviensis is found in the EZ of low mountainous Very Humid Forest.

White Sea's Severe Winter Hydrological Hazard and Its Effect On Decrease of Population of Greenland Seals (1998/99 Winter Ecological Catastrophe)

Science.gov (United States)

Melentyev, Konstantin V.; Chernook, Vladimir I.

soundig with resolution 20-25 m, changed situation. High transparency of snow and relatively deep penetration of signals in ice is basis of sub-surface sounding. SAR images allow fix documentary different ice parameters: development and arrangement, ice type, shape of floes, ice concentration and compactness. Unfortunately time being resolution couldn't resolve individual sea mammal. In order to investigate the ice regime, estimate number of seals at the different winter conditions and forecast the future tendency of population decrease we perform regularly ice reconnaissance. Accomplish these observations and computations more precisely could be done at the time of mass accumulation of seals, that is whelping and moulting period. Aerial inspection is difficult task: weather conditions and masking coloration obstructs the problems, sometimes mammals couldn't be quite founded. Comprehensive study of ERS SAR signatures for diagnosis type of winter hydrology of the Arctic seas and ice conditions produced by severe winter , assessment of possibility forecast of future development of ice and studying ice as non-biotic factor of ecology of Pagophilus groenladicus and other ice-associated forms of sea mammals is a new interdisciplinary approach in marine biology. First experience of such application SAR data for diagnosis of hydrological hazard produced by severe winter has been undertaken in the White Sea and contiguous seas in 1996. Sub-satellite experiments onboard nuclear icebreaker "Taymir" provided validation program, ice cores and water samples were gathered and evaluated using chemi-luminiscent methods in connection with seal' behavior patterns. Since then aircraft Antonov-26 «Arktika» provided ice and seals investigations systematically. Helicopter is employed for in situ observations, ice cores and water samples are investigated in laboratory for measurement of different pollutant , dissolved organic matter and other hydro-chemical and radio-physical paramet ers

A Triatoma maculata (Hemiptera, Reduviidae, Triatominae population from Roraima, Amazon region, Brazil, has some bionomic characteristics of a potential Chagas disease vector Uma população de Triatoma maculata (Hemiptera, Reduviidae, Triatominae proveniente de Roraima, Amazônia, Brasil, possui algumas características bionômicas de vetor potencial de doença de Chagas

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José Francisco Luitgards-Moura

2005-06-01

Full Text Available Even though Chagas disease is rare in the Brazilian Amazon, the conditions for the establishment of domiciliated cycles prevail in many areas where triatomines are of frequent occurrence. In Roraima, a previous serological and entomological survey in three agricultural settlements showed the existence of all transmission cycle elements, i.e., individuals infected by Trypanosoma cruzi, triatomine species previously found harboring T. cruzi in the broader Amazon region of neighboring countries and, domicile/ peridomicile conditions favorable to triatomine colonization. Triatoma maculata was the most frequent species, found in chicken houses in the peridomicile and sporadically within residences. Aiming to investigate the possibility of T. maculata to possess the potentiality to transmit T. cruzi in the area, bionomic characteristics were studied under laboratory conditions. These were feeding frequency, time for defecation after a blood meal, time elapsed in voluntary fasting pre- and pos-ecdysis, moulting time periods, pre-oviposition and oviposition periods and index of oviposition, incubation period, egg viability, longevity and mortality rate. Results show that the Passarão population of T. maculata should be considered a potential vector of T. cruzi since it shows a capacity to infest artificial ecotopes in the peridomicile, to carry out large number of meals during the nymphal cycle, to have a relatively short developmental cycle capable of producing 2.9 generations/year, to blood source eclecticism, to defecate immediately after the blood meal while still on the host and to the fact that has been previously found naturally infected by T.cruzi.A doença de Chagas é de rara ocorrência na Região Amazônica Brasileira, onde contudo as condições para o estabelecimento de ciclos domésticos existem. Um estudo previamente realizado em áreas de colonização agrícola no Estado de Roraima, mostrou a possibilidade de ciclos autóctones de

Mating behaviour of Pseudodiaptomus annandalei (Copepoda Calanoida) with emphasis on rejection rate

Science.gov (United States)

Dur, G.; Souissi, S.; Schmitt, F. G.; Hwang, J. S.; Cheng, S. H.

2009-04-01

Mating behaviour has important consequences at both individual and population levels. Reproductive fitness is of paramount importance to sustain the success of planktonic copepod populations in aquatic environments. The calanoid copepod Pseudodiaptomus annandalei has one of the largest geographical ranges for Indo-Pacific Pseudodiaptomidae. It is also of great importance in fish culture pounds south of Taiwan. However, the mating behavior of this species has never been studied. Mating and predatory behaviour are conceptually the same. In both cases, the encounter and the interactions occur between two individuals with opposite characteristics: predator-prey for predation; male-female for mating. The mating behaviour may be defined as a sequence of encounter, pursuit, capture and copulation. Several observed behaviour suggest that both sexes asses and choose among available mates before the copulation. Pre-copulatory mate choice in copepods may manifest as mate guarding where males attached to CV females until their final moult, complicated pre-copulatory dance and escaping. During our preliminary observations, we notice that P. annandalei females escape by shaking, often violently, the males that have caught them. Consequently for such a species the act of mating may be visualized as a chain of six events (i.e. search, encounter, pursuit, capture, selective dance, copulation).Within this chain, encounter, capture and copulation are conditional events depending on the successful conclusion of their preceding events in the chain. In this study, we examined the different step in the mating behaviour of the scarcely studied sub-tropical copepod, Pseudodiaptomus annandalei, collected from the Danshuei estuary (North Taiwan). The individuals were observed using a 3D optical system to obtain simultaneous front and side views. Males, when placed in the water where females had previously swum in, showed significant increase of their swimming velocities. Additionally, their

Estadísticos poblacionales de Triatoma sordida Stäl 1859 (Hemiptera : Reduviidae en condiciones experimentales Population statistics of Triatoma sordida Stäl 1859 (Hemiptera: Reduviidae in experimental conditions

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Elena B. Oscherov

1996-10-01

verificou-se na terceira semana no início do estádio adulto.A distribuição estável de idades de T. sordida seria de 32% ovos, 26% ninfas do primeiro estádio, 19% ninfas do segundo estádio, 13% ninfas do terceiro estádio, 6% ninfas do quarto estádio, 3% ninfas do quinto estádio e 1% de adultos. A análise dos parâmetros permite considerar que esta espécie comporta-se como K-estrategista em condições experimentais.Four cohorts of 100 Triatoma sordida eggs were reared under standard laboratory conditions (28ºC, 63% R.H. and fed weekly on hens during 40 minutes. The numbers of dead insects, moults and eggs laid were recorded weekly. A constant survival value was observed without any important peaks in the four cohorts. Life expectancy was 37.4 weeks for males and 36.8 weeks for females. The average generation time was 61.7 weeks. The average net reproduction rate suggests that this population would increase 143.2 times during each generation. The average intrinsic rate of natural increase was 0.082 per individual per week. The highest reproductive value was observed 3 weeks after entering the adult stage. The age structure, assuming stable age distribution, would be 32% eggs, 26% of first instar nymphs, 19% of second instar nymphs, 13% of third instar nymphs, 6% of fourth instar nymphs, 3% of fifth instar nymphs and 1% of adults. Our results suggest that this species behaves as a k-strategist under experimental conditions.

Effects of climate change on seashores; Effekter av klimaendringer for havstrand

Energy Technology Data Exchange (ETDEWEB)

Follestad, Arne; Evju, Marianne; Oedegaard, Frode

2011-04-15

, thermopile species, and the distribution range can be expected to be increased with increased temperatures and a prolonged growth period. The largest changes in occurrences and population sizes are likely to be in arctic plants with restricted, northern distributions. For invertebrates, the effects of climate change will be largely determined by the state of the habitats after a change. Species favouring open, partly vegetation free areas in the backshore parts of the seashore habitats will probably decline. Particularly vulnerable are species found in sand dune habitats. Species being favoured by mild winters and a prolonged growth period are expected to increase their abundance, given that the state of the habitats is not significantly changed. For birds, climate change will affect the distribution and occurrence of several species. This may bring about needs for change in protection plans, as important breeding and feeding areas for sea birds and other waterfowl may become unsuitable with increasing sea levels. This is also valid for moulting sites and breeding sites of Harbour seal and Grey seal, which are often located in remote areas offshore. Several countries have implemented measures to prevent negative impacts on seashores, such as coastal protection measures, both to protect particular localities, nature types or important social structures. Coastal protection measures may impair natural dynamic processes operating in coastal areas and thus reduce the ability of the ecosystems to adapt to the effects of climate change. It is therefore recommended that strategies are developed relatively quickly in order to meet the challenges that coastal protection measures may result in for nature types and threatened species. An assessment of the necessity of law change may be advisable in order to be able to prevent irreversible interventions in seashore ecosystems. It is recommended to further investigate the effects on seashores, based on new prognoses for sea level rise

Comparision of the Efficiency of the Current Oils and Insecticide Compounds in Control of Greenhouse Whitefly, Trialeurodes vaporariorum (Westwood, (Hem.: Aleyrodidae on Rose and their Interaction

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Asghar Hosseininia

2017-03-01

block design with 20 treatments, 3 blocks and 4 replications. In addition, the bioassay of neem oil, citowett and volk on nymphal stages (2-4 as well as whiteflies adult were assayed in the greenhouse condition. The bioassay was carried out in clear plastic cages containing a leaf with three leaflets connected to the plant, containing 30 nymphs or 30 adults. Moreover, the bioassay of deltamethrin on adults and buprofezin on the nymphs and also synergistic rate (SR of three oils including neem oil, citowett and volk on deltamethrin and buprofezin were estimated. The followed formula {SR= (Lc50A +Lc50B/Lc50 (A+B} was used for calculating synergistic rate. For bioassay testes, the clear plastic cages containing three leaflets as well as 30 nymphs and also 30 adult whiteflies were used. Results and Discussion: Based on the result of the mortality rate of oils and common insecticide, the treatment control, which was neem oil (1 ml/L mixed with deltamethrin (0.5 ml/L, was caused 91.72 and 90.79 % MR of nymphs and adult whiteflies, respectively. Also the neem oil (0.5 ml/L and citowett (0.25 ml/L after water treatment had the lowest effect on the adult and nymphal stages mortality. When the oils separately were used, their LC50 were higher than they used simultaneously with deltamethrin and buprofezin. The results of the bioassay showed the Lc50 of deltamethrin mixed with neem oil, citowett and volk as: 417.55, 290.51 and 639.07 ppm, respectively. The synergistic effect of neem oil, citowett and volk with deltamethrin on the mortality rate of adult whitefly was estimated as 3.62, 5.45 and 2.56, respectively. The highest SR (7.24 of buprofezin for nymphal stage was occurred when it mixed with citowett. In addition, the SR of this pesticide was 4.86 and 3.55 for neem and volk, respectively. Also the Lc50 of buprofezin mixed with neem, citowett and volk were 214.26, 177.32 and 559.56 ppm, respectively. Conclusion: According to the effect of buprofezin on insect moulting, using of

Marine wind farms - seabirds, white-tailed eagles, Eurasian eagle-owl and waders. A screening of potential conflict areas; Offshore vindenergianlegg - sjoefugl, havoern, hubro og vadere. En screening av potensielle konfliktomraader

Energy Technology Data Exchange (ETDEWEB)

Christensen-Dalsgaard, S.; Lorentsen, S.-H.; Dahl, E.L.; Follestad, A.; Hanssen, F.O.; Systad, G.H.

2010-06-15

sufficient quality to be used for this method. For the species where less data was available (e.g. geese, waders, white-tailed eagle and the Eurasian eagle-owl) we have chosen to illustrate potential conflicts by means of maps of the major functional areas. The results are presented in maps, where the WSI is given for 10x10 km squares. The results of the study showed a clear difference in WSI between areas and seasons. For the seabirds it was shown that especially the large breeding colonies in Vesteraalen, Roest and Runde were areas with high WSI. In Vesteraalen, the gannets and some of the puffin colonies resulted in a high WSI, while on Roest auks and for Runde gannets and gulls resulted in high WSI-values. Further south it was mainly gulls and terns that caused high WSI-values on the coast of Vest- Agder and between Jaeren and Karmoey. The results for the breeding season were as expected, as other studies have previously pointed to these sites as valuable areas. There were some similarities between important localities in summer and winter, for example between Jaeren and Vesteraalen. But during the winter season, areas such as Lista, Nordoeyerne and Gossen (Moere and Romsdal), Smoela, Froan, Oerlandet, Frost, Vikna and Vega also showed a high vulnerability. For the white-tailed sea eagle especially the islands of Smoela, Hitra and Froeya, as well as the area from Bodoe to Steigen were very important. For the Eurasian eagle-owl the coast of Helgeland and the areas surrounding Karmoey in Rogaland were most important. For waders and geese the focus was on important resting and moulting sites. Such sites for geese and eiders are distributed across the study area, with the most important and largest areas being the coast of central Norway and northwards. For waders a number of important resting areas are spread over the entire study area, but with a concentration of localities along the coast of Moere and Romsdal and Rogaland, especially along the coast of Jaeren. In our

Pre- and post-construction studies of conflicts between birds and wind turbines in coastal Norway (BirdWind)

Energy Technology Data Exchange (ETDEWEB)

Bevanger, K.; Berntsen, F.; Clausen, S.; Dahl, E.L.; Flagstad, Oe.; Follestad, A.; Halley, D.; Hanssen, F.; Hoel, P.L.; Johnsen, L.; Kvaloey, P.; May, R.; Nygaard, T.; Pedersen, H.C.; Reitan, O.; Steinheim, Y.; Vang, R.

2009-12-15

connection to the planned extension of the existing power plant on Hitra I; the Hitra II Wind-Power Plant. Since 2003, 50 nestlings of white-tailed eagle have been equipped with satellite transmitters. In 2009, eight WTE nestlings were tagged, six with solar-powered and two with battery-powered transmitters. One was tagged within the wind-power plant, the others in close vicinity of it. The solar-powered transmitters used in 2009 were programmed to give one position per hour during summer in order to have finer resolution of movements for risk-modeling purposes. During winter less frequent downloading is scheduled, due to low light and poor battery-charging. One of the tagged nestlings was found killed by a turbine October 7. We have continued to collect feathers from active nests and chicks also in 2009, as well as from eagles killed in collisions with wind turbines. DNA-analyses from bones of six eagles killed by electrocution on power-line pylons on Smoela will also be included. For increased efficiency in the laboratory, and to streamline the production of DNA-data, the use of an extraction robot has been implemented. All WTE nest sites on Smoela were surveyed during the summer. Territorial activity, identified by either moulted adult feathers, chicks in the nest or fresh nest material, was confirmed in 61 different territories on the main island and in the surrounding archipelago. In these territories 27 chicks from 21 different clutches were recorded. This is the second highest number of chicks recorded ever on Smoela, giving a re-productive output of 0.44 chicks/confirmed occupied territory. In order to investigate behavioural differences for the WTE related to the distance from the turbines, data on flight activity (moving flight, social behaviour and soaring) and flight height (below, in and above the rotor zone) were collected at 12 vantage points, 6 from inside the wind-power plant area and 6 from control areas close to the power-plant area. The results indicate

[Dynamics of infection of Fringilla coelebs chaffinch nestlings with feather mites (Acari: Analgoidea)].

Science.gov (United States)

Mironov, S V; Malyshev, L L

2002-01-01

on 11th day 60.3 +/- 5.7 mites per nestling. In the micropopulation of this species, the tritonymphs count 38.3%, and the quota of males and females is 25.3% each. The migration of this species goes most intensively, than in two other species. An analitic selection of logistic curves shows, that the increasing of mite number during the process of infection with three mite species may be most adequately described by the sigmoid curves with clearly recognizable levels of saturation, which can be theoretically reached. Indeed, the number of mite individuals being able to migrate onto the nestlings is limited by their number on a respective chaffinch female. In a contrast, the increasing of plumage indices, for instance the length of flight feathers, has almost linear character during the period of observation. The beginning of mite migration is determined by the development of respective microhabitats in the plumage of nestlings, or at least by the development of certain structure elements of plumage, where mites are able to attach for a while, before that moment, when the nestlings will develop the plumage completely and begin to fly. In three mite species examined, the process of infection was performed by older stages, namely by the imago and/or tritonymphs. This can be explained by two reasons. On the one hand, the older stages are most active in their movement, resistible and able to survive successfully on new host individuals. On the other hand, the older stage are ready for the reproduction or will be ready after one moulting. The older stages of mites can quickly create a large and self-supporting micropopulations on the birds, therefore this strategy ensures a successful subsequent existence of the parasite species. In cases, when mites (A. passerinus, M. microphylla) migrate into the respective microhabitats structurally corresponding to their normal microhabitats on adult birds, the micropopulations of these mite species include a significant or dominant

HERBAL SUPPLEMENTS: CAUSE FOR CONCERN?

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Paolo Borrione

2008-12-01

Full Text Available More than 1400 herbal products or herbal-derived compounds are commonly commercialised for health uses worldwide (Tyler, 1996. Herbs are considered dietary supplements, and therefore are subjected to a very limited form of regulation, and advertisements normally highlight their potential activities without mentioning any side effect. Also, herbs are generally believed to be 'natural', and hence safe. Many nutritional supplements contains herb compounds usually not present in the diet (e.g. Ginko biloba, horse- chestnut, and only 10% of the herbs used in nutritional supplements are commonly present in the food (e.g. garlic, soy, blueberry, green the, ginger, curcuma (Eisenberg et al., 1993. There is much interest in "alternative natural approaches" in sport. It is appealing for athletes to use 'natural' substances with similar activity to 'pharmacological' ones in term of improving performance, are not considered doping, and are considered side-effects free (Table 1. Indeed, many herbal dietary supplements marketed on internet are presented as legal alternative to illicit drugs (Denneey et al., 2005. EcdysteroidsEcdysteroids are the steroid hormones of arthropods (Figure 1. They also occur in some plants, where they are known as phytoecdysteroids, and are believed to contribute to deter invertebrate predators. In insects, they regulate moulting and metamorphosis, may regulate reproduction and diapause. Most actions of ecdysteroids are mediated by intracellular receptor complexes, which regulate gene expression in a tissue- and development-specific manner (Lehmann et al 1989.Several phytoecdysteroids have anabolic growth-promoting effects on mice, rats, pigs and Japanese quails. Ecdysteroids stimulate muscle growth, and this anabolic effect promotes increased physical performance without training. Ecdysteroids are also able to increase muscle ATP content in vitamin D-deprived rats (Báthori, 2002. Ecdysteroids stimulate protein synthesis in the

Use of Isotopes for Investigating the Behaviour and Ecology of Insect Pests in Some Recent Studies; Emploi des radioisotopes dans des recherches recentes sur le comportement et l'ecologie des insectes nuisibles; Ispol'zovanie radioizotopov dlya issledovaniya povedeniya i ehkologii nasekomykh-vreditelej v Irane; Empleo de isotopos en estudios recientes sobre el comportamiento y la ecologia de las plagas insectiles

Energy Technology Data Exchange (ETDEWEB)

Quraishi Sayeed, M. [Cento Institute of Nuclear Science, Teheran (Iran, Islamic Republic of)

1963-09-15

Investigations into the ecology, behaviour, dispersal and longevity of insects have always provided challenges to the entomologist. The use of isotopes is an effective tool and the following is a report on some interesting problems solved by their application. Anopheles stephensi is the main vector o f malaria in southern Iran. On P{sup 32}-labelled mosquitoes, the dispersal, behaviour, digestion of blood meal, maturation of ovaries and length of gonotrophic cycles were successfully worked out. It was found that in about 80% of the cases the mosquito needed two blood meals for the completion of the first cycle. The first cycle itself was completed in 4-5 d depending upon the temperature. Labelled mosquitoes which had emerged overnight were released in an isolated village. The ratio of active mosquitoes to total catch was worked out every day and thus, on the assumption that the natural population remained constant, the mortality rate, which was found to be exponential for the first six days, was worked out. The mating behaviour of the female was also studied by using normal females which had mated once with P{sup 32}-labelled males. It was found that the female mates more than once and that after mating with an active male, the spermathead became active. Counts of up to twice the background (12 counts/min) were obtained by using males giving about 15 000 counts/min. Studies of the injection of saliva in glucose solution during feeding were also made on P{sup 32}-labelled mosquitoes. Eurygaster integriceps is a serious pest of wheat in Iran, Pakistan and the Middle East. Using P{sup 32} activated wheat plants, the feeding behaviour of the first-instar nymph was investigated. Other foods, radioactively labelled, were also studied and it was found that feeding was essential for the first moult, even if the food consisted of water absorbed in a filter paper. (author) [French] Les recherches sur l'ecologie, le comportement, la dispersion et la longevite des insectes ont