WorldWideScience

Sample records for attract parasitoids effects

  1. Jasmonic acid-induced volatiles of Brassica oleracea attract parasitoids: effects of time and dose, and comparison with induction by herbivores.

    Science.gov (United States)

    Bruinsma, Maaike; Posthumus, Maarten A; Mumm, Roland; Mueller, Martin J; van Loon, Joop J A; Dicke, Marcel

    2009-01-01

    Caterpillar feeding induces direct and indirect defences in brassicaceous plants. This study focused on the role of the octadecanoid pathway in induced indirect defence in Brassica oleracea. The effect of induction by exogenous application of jasmonic acid (JA) on the responses of Brussels sprouts plants and on host-location behaviour of associated parasitoid wasps was studied. Feeding by the biting-chewing herbivores Pieris rapae and Plutella xylostella resulted in significantly increased endogenous levels of JA, a central component in the octadecanoid signalling pathway that mediates induced plant defence. The levels of the intermediate 12-oxophyto-dienoic acid (OPDA) were significantly induced only after P. rapae feeding. Three species of parasitoid wasps, Cotesia glomerata, C. rubecula, and Diadegma semiclausum, differing in host range and host specificity, were tested for their behavioural responses to volatiles from herbivore-induced, JA-induced, and non-induced plants. All three species were attracted to volatiles from JA-induced plants compared with control plants; however, they preferred volatiles from herbivore-induced plants over volatiles from JA-induced plants. Attraction of C. glomerata depended on both timing and dose of JA application. JA-induced plants produced larger quantities of volatiles than herbivore-induced and control plants, indicating that not only quantity, but also quality of the volatile blend is important in the host-location behaviour of the wasps. PMID:19451186

  2. Plant pathogen-induced volatiles attract parasitoids to increase parasitism of an insect vector

    Directory of Open Access Journals (Sweden)

    Xavier eMartini

    2014-05-01

    Full Text Available Interactions between plant pathogens and arthropods have been predominantly studied through the prism of herbivorous arthropods. Currently, little is known about the effect of plant pathogens on the third trophic level. This question is particularly interesting in cases where pathogens manipulate host phenotype to increase vector attraction and presumably increase their own proliferation. Indeed, a predator or a parasitoid of a vector may take advantage of this manipulated phenotype to increase its foraging performance. We explored the case of a bacterial pathogen, Candidatus Liberibacter asiaticus (Las, which modifies the odors released by its host plant (citrus trees to attract its vector, the psyllid Diaphorina citri. We found that the specialist parasitoid of D. citri, Tamarixia radiata, was attracted more toward Las-infected than uninfected plants. We demonstrated that this attractiveness was due to the release of methyl salicylate. Parasitization of D. citri nymphs on Las-infected plants was higher than on uninfected controls. Also, parasitization was higher on uninfected plants baited with methyl salicylate than on non-baited controls. This is the first report of a parasitoid ‘eavesdropping’ on a plant volatile induced by bacterial pathogen infection, which also increases effectiveness of host seeking behavior of its herbivorous vector.

  3. The Gastropod Menace: Slugs on Brassica Plants Affect Caterpillar Survival through Consumption and Interference with Parasitoid Attraction.

    Science.gov (United States)

    Desurmont, Gaylord A; Zemanova, Miriam A; Turlings, Ted C J

    2016-03-01

    Terrestrial molluscs and insect herbivores play a major role as plant consumers in a number of ecosystems, but their direct and indirect interactions have hardly been explored. The omnivorous nature of slugs makes them potential disrupters of predator-prey relationships, as a direct threat to small insects and through indirect, plant-mediated effects. Here, we examined the effects of the presence of two species of slugs, Arion rufus (native) and A. vulgaris (invasive) on the survivorship of young Pieris brassicae caterpillars when feeding on Brassica rapa plants, and on plant attractiveness to the main natural enemy of P. brassicae, the parasitoid Cotesia glomerata. In two separate predation experiments, caterpillar mortality was significantly higher on plants co-infested with A. rufus or A. vulgaris. Moreover, caterpillar mortality correlated positively with slug mass and leaf consumption by A. vulgaris. At the third trophic level, plants infested with slugs and plants co-infested with slugs and caterpillars were far less attractive to parasitoids than plants damaged by caterpillars only, independently of slug species. Chemical analyses confirmed that volatile emissions, which provide foraging cues for parasitoids, were strongly reduced in co-infested plants. Our study shows that the presence of slugs has the potential to affect insect populations, directly via consumptive effects, and indirectly via changes in plant volatiles that result in a reduced attraction of natural enemies. The fitness cost for P. brassicae imposed by increased mortality in presence of slugs may be counterbalanced by the benefit of escaping its parasitoids. PMID:27002323

  4. Variation in plant volatiles and attraction of the parasitoid Diadegma semiclausum (Hellén)

    OpenAIRE

    Bukovinszky, T.; Gols, R.; Posthumus, M.A.; Vet, L. E. M.; Lenteren, van, J.C.

    2005-01-01

    Differences in allelochemistry of plants may influence their ability to attract parasitoids.We studied responses of Diadegma semiclausum (Hellén), a parasitoid of the diamondback moth (Plutella xylostella L.), to inter- and intraspecific variation in odor blends of crucifers and a non-crucifer species. Uninfested Brussels sprout (Brassica oleracea L. gemmifera), white mustard (Sinapis alba L.), a feral Brassica oleracea, and malting barley (Hordeum vulgare L.) were compared for their attracti...

  5. The effect of initial density and parasitoid intergenerational survival rate on classical biological control

    International Nuclear Information System (INIS)

    Models of biological control have a long history of theoretical development that have focused on the interaction of a parasitoid and its host. The host-parasitoid systems have identified several important and general factors affecting the long-term dynamics of interacting populations. However, much less is known about how the initial densities of host-parasitoid populations affect the biological control as well as the stability of host-parasitoid systems. To do this, the classical Nicholson-Bailey model with host self-regulation and parasitoid intergenerational survival rate is used to uncover the effect of initial densities on the successful biological control. The results indicate that the simplest Nicholson-Bailey model has various coexistence with a wide range of parameters, including boundary attractors where the parasitoid population is absent and interior attractors where host-parasitoid coexists. The final stable states of host-parasitoid populations depend on their initial densities as well as their ratios, and those results are confirmed by basins of attraction of initial densities. The results also indicate that the parasitoid intergenerational survival rate increases the stability of the host-parasitoid systems. Therefore, the present research can help us to further understand the dynamical behavior of host-parasitoid interactions, to improve the classical biological control and to make management decisions

  6. Effects of terrestrial pollutants on insect parasitoids.

    Science.gov (United States)

    Butler, Casey D; Beckage, Nancy E; Trumble, John T

    2009-06-01

    Parasitoids are important organisms in the regulation of insect herbivores in natural, urban, and agricultural ecosystems. The impact of pollutants acting on parasitoids has not been extensively reviewed. This prompted us to propose a falsifiable null hypothesis (pollutants have no effects on parasitoids) and two alternative hypotheses (pollution negatively or positively affects parasitoids) to assess in the available literature the effects of pollutants acting on parasitoids. We found 26 studies examining 39 biological systems that met our criteria for inclusion. Of these studies, 18 of the 39 biological systems (46.2%) supported the null hypothesis while 18 (46.2%) supported the first alternative hypothesis in which pollutants exhibited negative effects on parasitoids. Only a small percentage of the studies (7.6%, 3 of 39) supported the second alternative hypothesis suggesting that pollutants had positive effects on parasitoids. We provide a synthesis of the available data by pollution type, summarize trends for different pollutants, and suggest future areas of research. PMID:19132813

  7. Variation in plant volatiles and attraction of the parasitoid Diadegma semiclausum (Hellén).

    Science.gov (United States)

    Bukovinszky, T; Gols, R; Posthumus, M A; Vet, L E M; Van Lenteren, J C

    2005-03-01

    Differences in allelochemistry of plants may influence their ability to attract parasitoids. We studied responses of Diadegma semiclausum (Hellén), a parasitoid of the diamondback moth (Plutella xylostella L.), to inter- and intraspecific variation in odor blends of crucifers and a non-crucifer species. Uninfested Brussels sprout (Brassica oleracea L. gemmifera), white mustard (Sinapis alba L.), a feral Brassica oleracea, and malting barley (Hordeum vulgare L.) were compared for their attractivity to D. semiclausum in a Y-tube bioassay. Odors from all plants were more attractive to the parasitoid than clean air. However, tested against each other, parasitoids preferred the volatile blend from the three cruciferous species over that of malting barley. Wasps also discriminated between uninfested crucifers: mustard was as attractive as feral B. oleracea, and both were more attractive than Brussels sprout. Attractivity of uninfested plants was compared with that of plants infested by larvae of the host P. xylostella. Host-infested mustard and Brussels sprout were more attractive than uninfested conspecifics. Interestingly, the volatile blends of uninfested white mustard and infested Brussels sprout were equally attractive. We also compared the volatile composition of different plant sources by collecting headspace samples and analysing them with GC-MS. Similarities of volatile profiles were determined by hierarchic clustering and non-metric scaling based on the Horn-index. Due to the absence of several compounds in its blend, the volatile profile of barley showed dissimilarities from blends of crucifers. The odor profile of white mustard was distinctly different from the two Brassicaceae. Feral Brassica oleracea odor profile was different from infested Brussels sprout, but showed overlap with uninfested Brussels sprout. Odor blends from infested and uninfested Brussels sprout were similar, and mainly quantitative differences were found. D. semiclausum appears to

  8. Protection via parasitism: Datura odors attract parasitoid flies, which inhibit Manduca larvae from feeding and growing but may not help plants.

    Science.gov (United States)

    Wilson, J K; Woods, H A

    2015-12-01

    Insect carnivores frequently use olfactory cues from plants to find prey or hosts. For plants, the benefits of attracting parasitoids have been controversial, partly because parasitoids often do not kill their host insect immediately. Furthermore, most research has focused on the effects of solitary parasitoids on growth and feeding of hosts, even though many parasitoids are gregarious (multiple siblings inhabit the same host). Here, we examine how a gregarious parasitoid, the tachinid fly Drino rhoeo, uses olfactory cues from the host plant Datura wrightii to find the sphingid herbivore Manduca sexta, and how parasitism affects growth and feeding of host larvae. In behavioral trials using a Y-olfactometer, female flies were attracted to olfactory cues emitted by attacked plants and by cues emitted from the frass produced by larval Manduca sexta. M. sexta caterpillars that were parasitized by D. rhoeo grew to lower maximum weights, grew more slowly, and ate less of their host plant. We also present an analytical model to predict how tri-trophic interactions change with varying herbivory levels, parasitization rates and plant sizes. This model predicted that smaller plants gain a relatively greater benefit compared to large plants in attracting D. rhoeo. By assessing the behavior, the effects of host performance, and the variation in ecological parameters of the system, we can better understand the complex interactions between herbivorous insects, the plants they live on and the third trophic level members that attack them. PMID:26298191

  9. Differential attraction of parasitoids in relation to specificity of kairomones from herbivores and their by-products

    Institute of Scientific and Technical Information of China (English)

    Sumera Afsheen; Xia Wang; Ran Li; Chuan-Shu Zhu; Yong-Gen Lou

    2008-01-01

    Infochemicals are used by foraging parasitoids in the host selection process from habitat preference until host recognition. Kairomones from the herbivore host plays a vital role in the attraction of parasitoids, particularly in the micro-habitat. Parasitoids are specifically attracted to their respective herbivore species even when different herbivores are present on the same plant. Chemicals emitted from different stages of host (eggs, larvae,pupae, adult), host by-products (e.g., frass, exuviae, mandibular gland secretions, defense secretions etc.), or intra-specific infocbemicals (pheromones) can be main signals for the parasitoids. Parasitoids can differentiate between host and non-host, between different hosts and host stages by perceiving specific volatile and contact kairomones from the host itself,host along with its by-product, by-products alone or intra-specific infochemicals; of which frass (by-product) and intra-specific infochemicals are the most reported ones. Adult and larval parasitoids have been reported to be attracted to kairomones of their target stage or byproduct of their host. Pupal parasitoids have been found to utilize kairomones from the preceding host stage while egg parasitoids are known to exploit a variety of host infochemicals,for example, either from eggs themselves or other non-target host stages, especially adults and adult-related by-products. The kairomonal chemicals identified so far include various groups, but mainly hydrocarbons. A high degree of host specificity and host acceptance is important for the parasitoids as any mistake may result in the loss of fitness.

  10. Host-parasitoid dynamics and the success of biological control when parasitoids are prone to allee effects.

    Science.gov (United States)

    Bompard, Anaïs; Amat, Isabelle; Fauvergue, Xavier; Spataro, Thierry

    2013-01-01

    In sexual organisms, low population density can result in mating failures and subsequently yields a low population growth rate and high chance of extinction. For species that are in tight interaction, as in host-parasitoid systems, population dynamics are primarily constrained by demographic interdependences, so that mating failures may have much more intricate consequences. Our main objective is to study the demographic consequences of parasitoid mating failures at low density and its consequences on the success of biological control. For this, we developed a deterministic host-parasitoid model with a mate-finding Allee effect, allowing to tackle interactions between the Allee effect and key determinants of host-parasitoid demography such as the distribution of parasitoid attacks and host competition. Our study shows that parasitoid mating failures at low density result in an extinction threshold and increase the domain of parasitoid deterministic extinction. When proned to mate finding difficulties, parasitoids with cyclic dynamics or low searching efficiency go extinct; parasitoids with high searching efficiency may either persist or go extinct, depending on host intraspecific competition. We show that parasitoids suitable as biocontrol agents for their ability to reduce host populations are particularly likely to suffer from mate-finding Allee effects. This study highlights novel perspectives for understanding of the dynamics observed in natural host-parasitoid systems and improving the success of parasitoid introductions. PMID:24116153

  11. Powdery mildew suppresses herbivore-induced plant volatiles and interferes with parasitoid attraction in Brassica rapa.

    Science.gov (United States)

    Desurmont, Gaylord A; Xu, Hao; Turlings, Ted C J

    2016-09-01

    The co-occurrence of different antagonists on a plant can greatly affect infochemicals with ecological consequences for higher trophic levels. Here we investigated how the presence of a plant pathogen, the powdery mildew Erysiphe cruciferarum, on Brassica rapa affects (1) plant volatiles emitted in response to damage by a specialist herbivore, Pieris brassicae; (2) the attraction of the parasitic wasp Cotesia glomerata and (3) the performance of P. brassicae and C. glomerata. Plant volatiles were significantly induced by herbivory in both healthy and mildew-infected plants, but were quantitatively 41% lower for mildew-infected plants compared to healthy plants. Parasitoids strongly preferred Pieris-infested plants to dually-infested (Pieris + mildew) plants, and preferred dually infested plants over only mildew-infected plants. The performance of P. brassicae was unaffected by powdery mildew, but C. glomerata cocoon mass was reduced when parasitized caterpillars developed on mildew-infected plants. Thus, avoidance of mildew-infested plants may be adaptive for C. glomerata parasitoids, whereas P. brassicae caterpillars may suffer less parasitism on mildew-infected plants in nature. From a pest management standpoint, the concurrent presence of multiple plant antagonists can affect the efficiency of specific natural enemies, which may in turn have a negative impact on the regulation of pest populations. PMID:27043839

  12. Effects of Intraspecific Competition and Host-Parasitoid Developmental Timing on Foraging Behaviour of a Parasitoid Wasp

    OpenAIRE

    Couchoux, Christelle; van Nouhuys, Saskya

    2013-01-01

    In a context where hosts are distributed in patches and susceptible to parasitism for a limited time, female parasitoids foraging for hosts might experience intraspecific competition. We investigated the effects of host and parasitoid developmental stage and intraspecific competition among foraging females on host-searching behaviour in the parasitoid wasp Hyposoter horticola. We found that H. horticola females have a pre-reproductive adult stage during which their eggs are not mature yet and...

  13. A tritrophic signal that attracts parasitoids to host-damaged plants withstands disruption by non-host herbivores

    Directory of Open Access Journals (Sweden)

    Turlings Ted CJ

    2010-11-01

    Full Text Available Abstract Background Volatiles emitted by herbivore-infested plants are highly attractive to parasitoids and therefore have been proposed to be part of an indirect plant defense strategy. However, this proposed function of the plant-provided signals remains controversial, and it is unclear how specific and reliable the signals are under natural conditions with simultaneous feeding by multiple herbivores. Phloem feeders in particular are assumed to interfere with plant defense responses. Therefore, we investigated how attack by the piercing-sucking cicadellid Euscelidius variegatus influences signaling by maize plants in response to the chewing herbivore Spodoptera littoralis. Results The parasitoid Cotesia marginiventris strongly preferred volatiles of plants infested with its host S. littoralis. Overall, the volatile emissions induced by S. littoralis and E. variegatus were similar, but higher levels of certain wound-released compounds may have allowed the wasps to specifically recognize plants infested by hosts. Expression levels of defense marker genes and further behavioral bioassays with the parasitoid showed that neither the physiological defense responses nor the attractiveness of S. littoralis infested plants were altered by simultaneous E. variegatus attack. Conclusions Our findings imply that plant defense responses to herbivory can be more robust than generally assumed and that ensuing volatiles convey specific information about the type of herbivore that is attacking a plant, even in complex situations with multiple herbivores. Hence, the results of this study support the notion that herbivore-induced plant volatiles may be part of a plant's indirect defense stratagem.

  14. Effects of urbanisation on the parasitoid community of a leafminer

    Science.gov (United States)

    Fenoglio, María S.; Salvo, Adriana; Estallo, Elizabet L.

    2009-03-01

    Urbanisation may have detrimental effects on communities of parasitoids, affecting their species richness, abundance, and species dominance. Here we investigated the influence of the degree of urbanisation on parasitoid communities of Liriomyza commelinae (Frost) (Diptera: Agromyzidae), a leafminer of Commelina erecta L. (Commelinaceae), in the city of Córdoba, Argentina. To study changes in species richness, the specific composition of parasitic complexes and their degree of impact on the leafminer, 18 sampling sites from the centre to the outskirts of the city were selected and different variables indicative of urbanisation were quantified in each site. During January and February of 2005 and 2006, all mined leaves found in each plant patch were collected and the following variables were estimated: proportion of mined patches, abundance of the leafminer, total parasitoid species richness, total parasitism rates and parasitism due to the most abundant parasitoid species. The percentage of mined patches and leafminer abundance increased with urbanisation degree. Estimates of parasitoid species richness were not influenced by urbanisation degree but increased with species richness of mined plants. Changes in the specific composition of species along the urbanisation gradient were observed. Although parasitism by one of the species studied was higher in more urbanised sites of the city, the total parasitism rate of L. commelinae was not affected by urbanisation degree, species richness of mined plants or leafminer abundance. It appears that urbanisation benefits the herbivore species here studied but not through altering parasitoid activity. Changes in parasitoid community composition reflex dissimilar tolerance to environmental conditions displayed by different parasitoid species.

  15. Rhizobacterial colonization of roots modulates plant volatile emission and enhances the attraction of a parasitoid wasp to host-infested plants.

    Science.gov (United States)

    Pangesti, Nurmi; Weldegergis, Berhane T; Langendorf, Benjamin; van Loon, Joop J A; Dicke, Marcel; Pineda, Ana

    2015-08-01

    Beneficial root-associated microbes modify the physiological status of their host plants and affect direct and indirect plant defense against insect herbivores. While the effects of these microbes on direct plant defense against insect herbivores are well described, knowledge of the effect of the microbes on indirect plant defense against insect herbivores is still limited. In this study, we evaluate the role of the rhizobacterium Pseudomonas fluorescens WCS417r in indirect plant defense against the generalist leaf-chewing insect Mamestra brassicae through a combination of behavioral, chemical, and gene-transcriptional approaches. We show that rhizobacterial colonization of Arabidopsis thaliana roots results in an increased attraction of the parasitoid Microplitis mediator to caterpillar-infested plants. Volatile analysis revealed that rhizobacterial colonization suppressed the emission of the terpene (E)-α-bergamotene and the aromatics methyl salicylate and lilial in response to caterpillar feeding. Rhizobacterial colonization decreased the caterpillar-induced transcription of the terpene synthase genes TPS03 and TPS04. Rhizobacteria enhanced both the growth and the indirect defense of plants under caterpillar attack. This study shows that rhizobacteria have a high potential to enhance the biocontrol of leaf-chewing herbivores based on enhanced attraction of parasitoids. PMID:25783487

  16. Host-plant mediated effects of root herbivory on insect seed predators and their parasitoids.

    Science.gov (United States)

    Masters, G J; Jones, T H; Rogers, M

    2001-04-01

    The effects of root herbivory on a tephritid seed predator (Terellia ruficauda) and its parasitoids were investigated. Soil fauna were manipulated by insecticide treatment; host plant (Cirsium palustre) phenology and the oviposition behaviour of both tephritid and parasitoids (Pteromalus elevatus and Torymus chloromerus) recorded. Although insecticide-treated (and hence reduced root herbivory) plants had larger flowerheads, population abundances of both tephritids and parasitoids were greater on thistle plants subjected to root herbivory. Percentage parasitism was similar in both treatments. Root herbivory is thought to enhance the nutrient quality of plants and this may have resulted in the tephritid preferentially feeding on thistles whose roots had been attacked. Parasitoids on these plants were probably affected by a combination of increased plant attractivity (as for the tephritids), smaller flowerheads aiding ovipositor entry and more tephritid hosts being present. This is the first study to show that root herbivores, through plant-mediated interactions, can affect seed herbivores and also, albeit indirectly through the host, natural enemy trophic levels. PMID:24577656

  17. Volatiles from intact and Lygus-damaged Erigeron annuus (L.) Pers. are highly attractive to ovipositing Lygus and its parasitoid Peristenus relictus Ruthe.

    Science.gov (United States)

    Halloran, Sean T; Mauck, Kerry E; Fleischer, Shelby J; Fleisher, Shelby F; Tumlinson, James H

    2013-08-01

    Trap cropping and biological control can provide a sustainable means of controlling insect pests. Insects in the genus Lygus (Hemiptera: Miridae) are major pests on cotton and horticultural crops throughout the United States, and pesticide resistance within Lygus populations necessitates more sustainable long-term management techniques. Here, we explore behavioral responses of Lygus bugs (L. rubrosignatus Knight) and an introduced parasitoid, Peristenus relictus (Hymenoptera: Braconidae), to a common field edge plant, Erigeron annuus, which has the potential to serve as a trap host. Erigeron annuus is attractive to Lygus in the field, with Lygus preferentially moving to Erigeron patches compared to more abundant cotton plants. To determine the role of odor cues in mediating this attraction, we collected volatiles from E. annuus with and without Lygus damage, and then tested the attractiveness of these volatiles vs. those of cotton to Lygus females and female P. relictus wasps using Y-tube and wind tunnel bioassays. We found that undamaged E. annuus emits high concentrations of a complex volatile blend (60+ compounds), with novel compounds induced and constitutive compounds up-regulated in response to damage. Additionally, both female Lygus bugs and female P. relictus wasps are highly attracted to E. annuus volatiles over those of cotton in almost every combination of damage treatments. Our results suggest that Erigeron annuus would be an effective trap plant to control Lygus in cotton, since it is highly attractive to both the pest and its natural enemy. PMID:23982679

  18. Variable effects of dipteran parasitoids and management treatment on grasshopper fecundity in a tallgrass prairie.

    Science.gov (United States)

    Laws, A N; Joern, A

    2012-04-01

    Grasshoppers host a number of parasitoids, but little is known about their impact on grasshopper life history attributes or how those impacts may vary with land use. Here, we report on a three-year survey of nine grasshopper species in a tallgrass prairie managed with fire and bison grazing treatments. We measured parasitoid prevalence and the impact of parasitoid infection on grasshopper fecundity to determine if grasshopper-parasitoid interactions varied with management treatment. Adult female grasshoppers were collected every three weeks from eight watersheds managed with different prescribed burning and grazing treatments. Grasshopper fecundity with and without parasitoids was estimated through dissections of reproductive tracts. Dipteran parasitoids from two families (Nemestrinidae and Tachinidae) were observed infecting grasshoppers. We found significant effects of grazing treatment, but not burn interval, on grasshopper-parasitoid interactions. Parasitoids were three times more abundant in watersheds with bison grazing than in ungrazed watersheds, and the relative abundance of nemestrinid and tachinid flies varied with grazing treatment. Parasitoid prevalence varied among grasshopper species from <0.01% infected (Mermiria bivittata) to 17% infected (Hypochlora alba). Parasitoid infection reduced individual grasshopper fecundity, with stronger effects on current reproduction than on past reproduction. Furthermore, current fecundity in parasitized grasshoppers was lower in grazed watersheds compared to ungrazed watersheds. Nemestrinid parasitoids generally had stronger impacts on grasshopper fecundity than tachinid parasitoids, the effects of which were more variable. PMID:21944288

  19. The Effects of Aphid Traits on Parasitoid Host Use and Specialist Advantage

    Science.gov (United States)

    Gagic, Vesna; Petrović-Obradović, Olivera; Fründ, Jochen; Kavallieratos, Nickolas G.; Athanassiou, Christos G.; Starý, Petr; Tomanović, Željko

    2016-01-01

    Specialization is a central concept in ecology and one of the fundamental properties of parasitoids. Highly specialized parasitoids tend to be more efficient in host-use compared to generalized parasitoids, presumably owing to the trade-off between host range and host-use efficiency. However, it remains unknown how parasitoid host specificity and host-use depends on host traits related to susceptibility to parasitoid attack. To address this question, we used data from a 13-year survey of interactions among 142 aphid and 75 parasitoid species in nine European countries. We found that only aphid traits related to local resource characteristics seem to influence the trade-off between host-range and efficiency: more specialized parasitoids had an apparent advantage (higher abundance on shared hosts) on aphids with sparse colonies, ant-attendance and without concealment, and this was more evident when host relatedness was included in calculation of parasitoid specificity. More traits influenced average assemblage specialization, which was highest in aphids that are monophagous, monoecious, large, highly mobile (easily drop from a plant), without myrmecophily, habitat specialists, inhabit non-agricultural habitats and have sparse colonies. Differences in aphid wax production did not influence parasitoid host specificity and host-use. Our study is the first step in identifying host traits important for aphid parasitoid host specificity and host-use and improves our understanding of bottom-up effects of aphid traits on aphid-parasitoid food web structure. PMID:27309729

  20. Effects of student physical attractiveness

    Directory of Open Access Journals (Sweden)

    Krnjajić Stevan B.

    2005-01-01

    Full Text Available Implicit personality theories suggest that people draw conclusions about other persons by using a relatively small number of visible features. The formation of "the first impression" is influenced by the factors, such as sex, age, appearances, race or nationality. Frequently, conclusions based on those factors lead to developing social stereotypes. Attractiveness is a good example of "the first impression" effect, because physical attractiveness entails the creation of impression about another person along a relatively great number of dimensions. Experimental paradigm, introduced in the sphere of interpersonal perception around the mid-20th century, led to a relatively great number of studies on stereotype based on physical attractiveness. One of the most often quoted conclusions of studies on physical attractiveness is summarized by the idiom "what is beautiful is good". For example, socially desirable personality traits (responsibility kindness, energy quality, modesty, more successful private and professional life, are all attributed to physically attractive persons. In addition physical attractiveness is coupled with positive expectations, peer acceptance, academic achievement etc. On the basis of studies on the "what is beautiful is good" stereotype, we have situated our analysis within the domain of roles regulating social interaction between teachers and students i.e. effects of physical attractiveness on teacher expectations, peer acceptance and academic achievement.

  1. Effects of student physical attractiveness

    OpenAIRE

    Krnjajić Stevan B.

    2005-01-01

    Implicit personality theories suggest that people draw conclusions about other persons by using a relatively small number of visible features. The formation of "the first impression" is influenced by the factors, such as sex, age, appearances, race or nationality. Frequently, conclusions based on those factors lead to developing social stereotypes. Attractiveness is a good example of "the first impression" effect, because physical attractiveness entails the creation of impression about anothe...

  2. Induced parasitoid attraction by Arabidopsis thaliana : involvement of the octadecanoid and the salicylic acid pathway

    NARCIS (Netherlands)

    Poecke, van M.P.; Dicke, M.

    2002-01-01

    Plants can use indirect defence mechanisms to protect themselves against herbivorous insects. An example of such an indirect defence mechanism is the emission of volatiles by plants induced by herbivore feeding. These volatiles can attract the natural enemies of these herbivores, for example, parasi

  3. Complex effects of parasitoids on pharmacophagy and diet choice of a polyphagous caterpillar.

    Science.gov (United States)

    Smilanich, Angela M; Mason, Peri A; Sprung, Lucy; Chase, Thomas R; Singer, Michael S

    2011-04-01

    This study investigates complex effects of parasitoid infection on herbivore diet choice. Specifically, we examine how immunological resistance, parasitoid infection stage, and parasitoid taxonomic identity affect the pharmacophagous behavior of the polyphagous caterpillar, Grammia incorrupta (Arctiidae). Using a combination of lab and field experiments, we test the caterpillar's pharmacophagous response to pyrrolizidine alkaloids (PAs) over the course of parasitoid infection, as well as the effect of dietary PAs on the caterpillar's immunological response. Previous work from other systems gave the prediction that dietary PAs would be detrimental to the immune response and thus less acceptable to feeding early in the infection, when encapsulation of the parasitoid is most crucial. We found that the feeding acceptability of PAs was indeed low for caterpillars with early-stage parasitoid infections; however, this was not explained by PA interference with immune function. When allowed to choose among three host plant species, individuals harboring early-stage parasitoids increased their consumption of a nutritious plant containing antioxidants. This result was driven by wasp-parasitized caterpillars, whereas fly-parasitized caterpillars increased their consumption of plants containing iridoid glycosides. Individuals in the later time phase of infection exhibited an increase in PA intake that was consistent with previously reported self-medication behavior during late-stage parasitoid infection. This study reveals the depth of complexity and the dynamic nature of herbivore host plant choice, and underscores the importance of considering multitrophic interactions when studying insect diet choice. PMID:20941512

  4. Effect of Parasitoid: Host Ratio and Group Size on Fitness of Spathius galinae (Hymenoptera: Braconidae): Implications for Mass-Rearing.

    Science.gov (United States)

    Watt, Timothy J; Duan, Jian J; Tallamy, Douglas W; Hough-Goldstein, Judith

    2015-06-01

    Producing insect natural enemies in laboratories or insectaries for biological pest control is often expensive, and developing cost-effective rearing techniques is a goal of many biological control programs. Spathius galinae Belokobylskij and Strazenac (Hymenoptera: Braconidae), a newly described ectoparasitoid of emerald ash borer, Agrilus planipennis Fairmaire (Coleoptera: Buprestidae), is currently being evaluated for environmental introduction in the United States to provide biological control of this invasive pest. To improve mass-rearing outcomes for S. galinae, we investigated the effects of parasitoid: host ratio and parasitoid and host group size (density) on parasitoid fitness. Our results showed that when 1 emerald ash borer larva was exposed to 1, 2, 4, or 8 female parasitoids, parasitism rate was positively associated with increasing parasitoid: host ratio, while brood size, sex ratio, and fitness estimates of progeny were not affected. When a constant 1:1 parasitoid: host ratio was used, but group size varied from 1 female parasitoid and 1 host, 5 parasitoids and 5 hosts, 10 of each, and 20 of each in same size rearing cages, parasitism rates were highest when at least 5 females were exposed to 5 host larvae. Moreover, the number of progeny produced per female parasitoid was greatest when group size was 10 parasitoids and 10 hosts. These findings demonstrate that S. galinae may be reared most efficiently in moderately high-density groups (10 parasitoids and hosts) and with a 1:1 parasitoid: host ratio. PMID:26470215

  5. Effects of Abiotic Factors on HIPV-Mediated Interactions between Plants and Parasitoids.

    Science.gov (United States)

    Becker, Christine; Desneux, Nicolas; Monticelli, Lucie; Fernandez, Xavier; Michel, Thomas; Lavoir, Anne-Violette

    2015-01-01

    In contrast to constitutively emitted plant volatiles (PV), herbivore-induced plant volatiles (HIPV) are specifically emitted by plants when afflicted with herbivores. HIPV can be perceived by parasitoids and predators which parasitize or prey on the respective herbivores, including parasitic hymenoptera. HIPV act as signals and facilitate host/prey detection. They comprise a blend of compounds: main constituents are terpenoids and "green leaf volatiles." Constitutive emission of PV is well known to be influenced by abiotic factors like temperature, light intensity, water, and nutrient availability. HIPV share biosynthetic pathways with constitutively emitted PV and might therefore likewise be affected by abiotic conditions. However, the effects of abiotic factors on HIPV-mediated biotic interactions have received only limited attention to date. HIPV being influenced by the plant's growing conditions could have major implications for pest management. Quantitative and qualitative changes in HIPV blends may improve or impair biocontrol. Enhanced emission of HIPV may attract a larger number of natural enemies. Reduced emission rates or altered compositions, however, may render blends imperceptible to parasitoides and predators. Predicting the outcome of these changes is highly important for food production and for ecosystems affected by global climate change. PMID:26788501

  6. Livestock bedding effects on two species of parasitoid wasps of filth flies.

    Science.gov (United States)

    King, B H; Colyott, K L; Chesney, A R

    2014-01-01

    Choice of livestock bedding has been shown to affect density of filth fly maggots. Here, laboratory experiments indicate that bedding type can also affect natural enemies of the flies, specifically the parasitoid wasps Spalangia endius Walker and Urolepis rufipes (Ashmead) (Hymenoptera: Pteromalidae) parasitizing a natural host, the house fly Musca domestica L. (Diptera: Muscidae). For both parasitoid species, when females parasitized hosts under bedding, cedar shavings resulted in fewer parasitoids compared with pine shavings, but pine shavings did not differ from wood pellets and corn cob pellets. In the absence of exposure to hosts, longevity of adult females was reduced in cedar shavings compared with pine shavings and pellets. In contrast to the effects on parasitization and on adult survival, shavings treatment had no significant effect on the number of parasitoids or flies that emerged when hosts were not exposed to shavings until after parasitization. PMID:25480971

  7. Overview of parasitism associated effects on host haemocytes in larval parasitoids and comparison with effects of the egg-larval parasitoid Chelonus inanitus on its host Spodoptera littoralis.

    Science.gov (United States)

    Lanzrein, B; Pfister-Wilhelm, R; Wyler, T; Trenczek, T; Stettler, P

    1998-09-01

    In the first part we review the effects of larval endoparasitoids and their polydnavirus and venom on the immune system of their hosts. In all systems investigated, haemocyte spreading and encapsulation activity was reduced; in some cases effects on total (THC) or differential (DHC) haemocyte count as well as modification of haemocyte morphology and ultrastructure were also documented. In many cases polydnavirus (and venom) were shown to play a major role in abrogation of the host's immune reaction. In the second part we present the first investigation of effects of parasitism and polydnavirus/venom on the immune system of the host for an egg-larval parasitoid, Chelonus inanitus. We observed that in 4th and 5th instar larvae, i.e. 7 to 10 days after parasitization, neither haemocyte spreading and encapsulation activity, nor DHC, nor haemocyte ultrastructure were altered. After parasitization with X-ray irradiated wasps, which inject polydnavirus and venom and infertile eggs, there was no alteration of the above mentioned parameters. Nevertheless, parasitoid larvae implanted into 4th instar larvae which developed from eggs parasitized with X-ray irradiated wasps were not encapsulated, whereas co-injected latex beads were. These results show that parasitism by this egg-larval parasitoid does not generally suppress the host's immune system but that polydnavirus/venom injected at oviposition prevent, by, as yet unknown mechanisms, encapsulation of the parasitoid larva. PMID:12769877

  8. Physical Distance and Attraction: An Intensification Effect

    Science.gov (United States)

    Schiffenbauer, Allen; Schiavo, R. Steven

    1976-01-01

    This study was designed to test the effects of both interaction distance and the quality of the interaction upon attraction. The implications of this research for studies concerning crowding is discussed, as are possible explanatory mechanisms. (Editor/RK)

  9. A group's physical attractiveness is greater than the average attractiveness of its members : The group attractiveness effect

    NARCIS (Netherlands)

    van Osch, Y.M.J.; Blanken, Irene; Meijs, Maartje H. J.; van Wolferen, Job

    2015-01-01

    We tested whether the perceived physical attractiveness of a group is greater than the average attractiveness of its members. In nine studies, we find evidence for the so-called group attractiveness effect (GA-effect), using female, male, and mixed-gender groups, indicating that group impressions of

  10. Effects of plant availability on population size and dynamics of an insect community: diamondback moth and two of its parasitoids.

    Science.gov (United States)

    Soufbaf, M; Fathipour, Y; Karimzadeh, J; Zalucki, M P

    2014-08-01

    To understand the effect of plant availability/structure on the population size and dynamics of insects, a specialist herbivore in the presence of two of its parasitoids was studied in four replicated time-series experiments with high and low plant availabilities; under the latter condition, the herbivore suffered from some periods of resource limitation (starvation) and little plant-related structural refuges. Population dynamics of the parasitoid Cotesia vestalis was governed mainly by the delayed density-dependent process under both plant setups. The parasitoid, Diadegma semiclausum, under different plant availabilities and different coexistence situations (either +competitor or -competitor) showed dynamics patterns that were governed mainly by the delayed density process (significant lags at weeks 2-4). Both the competing parasitoids did not experience beneficial or costly interferences from each other in terms of their own population size when the plant resource was limited. Variation in the Plutella xylostella population under limited plant availability is higher than that under the other plant setup. For both parasitoids, under limited plant setup, the extinction risk was lower when parasitoids were engaged in competition, while under the unlimited plant setup, the mentioned risk was higher when parasitoids competed. In this situation, parasitoids suffered from two forces, competition and higher escaped hosts. PMID:24521693

  11. A group's physical attractiveness is greater than the average attractiveness of its members: the group attractiveness effect.

    Science.gov (United States)

    van Osch, Yvette; Blanken, Irene; Meijs, Maartje H J; van Wolferen, Job

    2015-04-01

    We tested whether the perceived physical attractiveness of a group is greater than the average attractiveness of its members. In nine studies, we find evidence for the so-called group attractiveness effect (GA-effect), using female, male, and mixed-gender groups, indicating that group impressions of physical attractiveness are more positive than the average ratings of the group members. A meta-analysis on 33 comparisons reveals that the effect is medium to large (Cohen's d = 0.60) and moderated by group size. We explored two explanations for the GA-effect: (a) selective attention to attractive group members, and (b) the Gestalt principle of similarity. The results of our studies are in favor of the selective attention account: People selectively attend to the most attractive members of a group and their attractiveness has a greater influence on the evaluation of the group. PMID:25733515

  12. Adaptive evolution of a generalist parasitoid: implications for the effectiveness of biological control agents

    OpenAIRE

    Zepeda-Paulo, Francisca A; Ortiz-Martínez, Sebastián A; Figueroa, Christian C.; Lavandero, Blas

    2013-01-01

    The use of alternative hosts imposes divergent selection pressures on parasitoid populations. In response to selective pressures, these populations may follow different evolutionary trajectories. Divergent natural selection could promote local host adaptation in populations, translating into direct benefits for biological control, thereby increasing their effectiveness on the target host. Alternatively, adaptive phenotypic plasticity could be favored over local adaptation in temporal and spat...

  13. Flowering plant effects on adults of the stink bug parasitoid Aridelus rufotestaceus (Hymenoptera: Braconidae)

    Science.gov (United States)

    Many parasitoids require food resources, such as nectar and pollen, besides hosts in order to optimize their life histories. This has led to interest in using these resources in pest management. Here we assess the potential effects of two floral plants, Fagopyrum esculentum and Gaillardia pulchella ...

  14. Plant allelochemicals and insect parasitoids effects of nicotine onCotesia congregata (say) (Hymenoptera: Braconidae) andHyposoter annulipes (Cresson) (Hymenoptera: Ichneumonidae).

    Science.gov (United States)

    Barbosa, P; Saunders, J A; Kemper, J; Trumbule, R; Olechno, J; Martinat, P

    1986-06-01

    Parasitoids developing within tobacco hornworms or fall army-worms exhibit significant differences in development and survival depending on whether their hosts fed on nicotine-free or nicotine-containing diets. The effects of nicotine were more severe on the relatively less adapted parasitoid,H. annulipes than the specialist parasitoid,Cotesia congregata. Labeled alkaloid originally placed in herbivore diet was incorporated in several parasitoid tissues. These results suggest that interactions between plant allelochemicals and parasitoids should be considered in the development of theory on insect herbivory and plant defense. PMID:24307111

  15. Juvenile and sublethal effects of selected pesticides on the leafminer parasitoids Hemiptarsenus varicornis and Diglyphus isaea (Hymenoptera: Eulophidae) from Australia.

    Science.gov (United States)

    Bjorksten, Tracey A; Robinson, Michelle

    2005-12-01

    The pest leafminers Liriomyza huidobrensis (Blanchard), Liriomyza sativae (Blanchard), and Liriomyza trifolii (Burgess) (Diptera: Agromyzidae) have spread into South East Asia and Oceania, and they are likely to reach Australia in the near future. Two translaminar pesticides, cyromazine and abamectin, currently provide effective chemical control of these pests, but because parasitoids can play an important role in controlling and preventing leafminer outbreaks, understanding the impact of pesticides on leafminer parasitoids is vital. Here, we tested larval and pupal mortality and sublethal effects of abamectin, cyromazine, and the widely used fungicide mancozeb on two common Australian leafminer parasitoids, Hemiptarsenus varicornis (Girault) and Diglyphus isaea (Walker). Abamectin caused significant mortality to larvae and pupae of both parasitoid species but cyromazine and mancozeb did not. Progeny production and longevity of H. varicornis were not affected by adult exposure to cyromazine and mancozeb, nor did direct pupal exposure decrease number of progeny produced by either parasitoid. Mortality of H. varicornis females emerging from leaves treated with abamectin was high for up to 72 h after eclosion but those surviving beyond 72 h did not differ from control females in the number of progeny produced. Mancozeb did not influence leaf residence time or parasitism by H. varicornis females. Cyromazine and the fungicide mancozeb were concluded to be compatible with the parasitoids tested and suitable for integrated pest management of leafminers should outbreaks of pest species occur in Australia. Abamectin should be used with caution because it caused significant mortality in both parasitoids tested here. PMID:16539101

  16. Effect of the irradiated food on the development of the egg parasitoid, Trichogramma chilonis (Ishii)

    International Nuclear Information System (INIS)

    Full text: Trichogrammatids, due to their amenability for mass-production, have the distinction of being the most frequently released natural enemies in the world. In many management programmes they fit as a key control component because they are found in a wide climatic range from temperate to tropical regions. It is estimated that over 18 million ha are annually treated with Trichogramma species in 16 different countries. About 18 species are being used to suppress pests on maize, sugarcane, rice, sugar beet, pine and vegetables. Out of many parasitoid species, Trichogramma chilonis Ishii is one of the most potent wasps and is extensively used in mass-releases against a number of lepidopteran pests in Asia. The irradiation of this parasitoid and its adult food with low doses of gamma radiation may induce useful characters/biological attributes viz., parasitisation, fecundity, emergence, sex ratio, etc. which might be exploited for improving the efficiency of the parasitoid. No practical information is available on the effect of irradiated adult food for incorporation of better biological attributes. In view of this, the present study was designed to investigate the effect of irradiated adult food on T. chilonis, which may lead to a better understanding of the role of irradiated food on the life of the parasitoid. Adult parasitoids were fed daily with fine streaks of either 50% honey, 20% of fructose/sucrose/glucose/yeast hydrolysate, and also on grape juice or distilled water, drawn on the inside wall of the tube with a fine needle. A group of parasitoids were also kept unfed during the course of the experiment. Proper care was taken to make streaks of the right thickness so that the parasitoids could be fed on them without getting stuck. For more critical and precise studies, the presence or absence of the food was observed at 10-hour intervals. This experiment was continued up to five successive generations of the parasitoid and in each generation freshly

  17. Side-Effects of Glyphosate to the Parasitoid Telenomus remus Nixon (Hymenoptera: Platygastridae).

    Science.gov (United States)

    Stecca, C S; Bueno, A F; Pasini, A; Silva, D M; Andrade, K; Filho, D M Z

    2016-04-01

    The aim of this study was to compare the side-effects of glyphosate to the parasitoid Telenomus remus Nixon (Hymenoptera: Platygastridae) when parasitoids were exposed to this chemical at the pupal (inside host eggs) and adult stages. Bioassays were conducted under laboratory conditions according to the International Organization for Biological Control (IOBC) standard methods for testing side-effects of pesticides to egg parasitoids. Different glyphosate-based pesticides (Roundup Original®, Roundup Ready®, Roundup Transorb®, Roundup WG®, and Zapp Qi®) were tested at the same acid equivalent concentration. Treatments were classified following the IOBC toxicity categories as (1) harmless, (2) slightly harmful, (3) moderately harmful, and (4) harmful. When tested against T. remus adults, Roundup Original®, Roundup Ready®, Roundup Transorb®, and Roundup WG® reduced parasitism 2 days after parasitoid emergence, being classified as slightly harmful. Differently, when tested against T. remus pupae, all tested glyphosate-based products did not differ in their lethal effect and therefore did not reduce T. remus adult emergence or parasitism capacity, being classified as harmless. However, differences on sublethal toxicity were found. Parasitism of individuals emerging from parasitized eggs sprayed at the pupal stage of T. remus with Zapp Qi® was lower compared to control, but parasitism was still higher than 66%, and therefore, Zapp Qi® was still classified as harmless. In conclusion, all tested glyphosate-based products can be used in agriculture without negative impact to T. remus as none was classified as harmful or moderately harmful to this parasitoid when exposure occurred at the pupal or adult stages. PMID:26842914

  18. Effects of entomopathogenic fungi on different developmental stages of Cotesia flavipes (Cam. a parasitoid of Diatraea flavipennella (Box (Lepidoptera: Crambidae

    Directory of Open Access Journals (Sweden)

    Cinthia Conceição Matias da Silva

    2016-02-01

    Full Text Available Biological control using the parasitoid Cotesia flavipes (Cam. is one of the main components in the integrated management of the sugarcane moth borer Diatraea spp. Besides this parasitoid, the entomopathogenic fungi Beauveria bassiana (Bals. Vuill and Metarhizium anisopliae (Metsch. Sorok. are used to control sugarcane pests, and they can be found naturally parasitizing caterpillars. This study aimed to evaluate the effects of M. anisopliae and B. bassiana on different developmental stages of the C. flavipes parasitoid on Diatraea flavipennella (Box. The experiments were carried at laboratory with isolates PL 43 of M. anisopliae and ESALQ 447 of B. bassiana were applied to the parasitoid at the immature and adult phases. No negative effects were observed on the larval development of C. flavipes, and it could complete its development on caterpillars of D. flavipennella treated with fungi. The fungi did not cause pupal mortality. However, B. bassiana caused high mortality in the adult parasitoid (76%. The fungi had negative effects on parasitoids when applied during certain developmental stages of C. flavipes.

  19. Attraction Effects in Honorific Agreement in Korean

    Science.gov (United States)

    Kwon, Nayoung; Sturt, Patrick

    2016-01-01

    Previous studies have suggested that sentence processing is mediated by content-addressable direct retrieval processes (McElree, 2000; McElree et al., 2003). However, the memory retrieval processes may differ as a function of the type of dependency. For example, while many studies have reported facilitatory intrusion effects associated with a structurally illicit antecedent during the processing of subject-verb number or person agreement and negative polarity items (Pearlmutter et al., 1999; Xiang et al., 2009; Dillon et al., 2013), studies investigating reflexives have not found consistent evidence of intrusion effects (Parker et al., 2015; Sturt and Kwon, 2015; cf. Nicol and Swinney, 1989; Sturt, 2003). Similarly, the memory retrieval processes could be also sensitive to cross-linguistic differences (cf. Lago et al., 2015). We report one self-paced reading experiment and one eye-tracking experiment that examine the processing of subject-verb honorific agreement, a dependency that is different from those that have been studied to date, in Korean, a typologically different language from those previously studied. The overall results suggest that the retrieval processes underlying the processing of subject-verb honorific agreement in Korean are susceptible to facilitatory intrusion effects from a structurally illicit but feature-matching subject, with a pattern that is similar to subject-verb agreement in English. In addition, the attraction effect was not limited to the ungrammatical sentences but was also found in grammatical sentences. The clear attraction effect in the grammatical sentences suggest that the attraction effect does not solely arise as the result of an error-driven process (cf. Wagers et al., 2009), but is likely also to result from general mechanisms of retrieval processes of activating of potential items in memory (Vasishth et al., 2008).

  20. Fitness Effects of Food Resources on the Polyphagous Aphid Parasitoid, Aphidius colemani Viereck (Hymenoptera: Braconidae: Aphidiinae)

    Science.gov (United States)

    Charles, Jennifer J.; Paine, Timothy D.

    2016-01-01

    Conservation biological control involving the polyphagous aphid parasitoid, Aphidius colemani Viereck, may include provisioning resources from a variety of plant sources. The fitness of adult A. colemani was enhanced with the provision of food resources such as floral nectar from a range of both native and introduced plant species and aphid honeydew under laboratory conditions. However, enhanced fitness appeared to be species specific rather than associated with the whether the plant was a native or an introduced species. Parasitoid survival and fecundity were enhanced significantly in response to the availability of floral nectar and honeydew compared to the response to available extrafloral nectar. These positive effects on the parasitoid’s reproductive activity can improve the effectiveness of conservation biological control in nursery production systems because of the abundance and diversity of floral resources within typical production areas. Additionally, surrounding areas of invasive weeds and native vegetation could serve as both floral resources and honeydew food resources for A. colemani. PMID:26808191

  1. Lethal and sublethal effects of four essential oils on the egg parasitoids Trissolcus basalis.

    Science.gov (United States)

    Werdin González, Jorge Omar; Laumann, Raúl Alberto; da Silveira, Samantha; Moraes, Maria Carolina Blassioli; Borges, Miguel; Ferrero, Adriana Alicia

    2013-07-01

    The essential oils from leaves of Schinus molle var. areira, Aloysia citriodora, Origanum vulgare and Thymus vulgaris have showed potential as phytoinsecticides against the green stink bug, Nezara viridula. In this work were evaluated their toxicological and behavioral effects on the parasitoid Trissolcus basalis, a biological control agent of this pest insect. Essential oils were obtained via hydrodestillation from fresh leaves. Insecticide activity in T. basalis females was evaluated in direct contact and fumigation bioassays. Behavioral effects were evaluated in olfactometer bioassays. To evaluate the residual toxicity, females of the parasitoids were exposed to oil residues; in these insects, the sublethal effects were evaluated (potential parasitism and survivorship of immature stages). The essential oils from O. vulgare and T. vulgaris proved to be highly selective when used as fumigant and did not change parasitoid behavior. After one week, the residues of these oils were harmless and did not show sublethal effects against T. basalis. According with these results, essential oils have potential applications for the integrated management of N. viridula. PMID:23664473

  2. Habitat amount modulates the effect of patch isolation on host-parasitoid interactions

    OpenAIRE

    ValérieCoudrain; ChristofSchüepp

    2014-01-01

    1. Habitat amount and patch isolation are important determinants of biodiversity and ecosystem functioning. We studied the separate and interactive effects of these two components of habitat fragmentation on host-parasitoid interactions in a replicated landscape-scale study. 2. We used trap-nesting solitary bees, wasps and their natural enemies as study system. We exposed trap nests in 30 tree patches in agricultural landscapes in northern Switzerland. Study sites were either (i) adjacent...

  3. Effects of some insecticides on the adult of Sunn pest egg parasitoids Trissolcus spp. (Hymenoptera: Scelionidae)

    OpenAIRE

    BABAROĞLU, Numan E.; UĞUR, Avni

    2011-01-01

    This study, was done to determine the effects of the most widespread used insecticides, fenitrothion and zetacypermethrin in order to control sunn pest, the most important pest of cereal to adult of egg parasitoid (Trissolcus spp) of Sunn pest were determined under laboratory and field condition in the years of 2003 and 2004. Both EC and ULV formulations of these insecticides were assessed as harmful under laboratory and field conditions.

  4. Effects of food deprivation on host feeding and parasitism of whitefly parasitoids.

    Science.gov (United States)

    Zang, Lian-Sheng; Liu, Tong-Xian

    2010-06-01

    Most whitefly parasitoids kill whiteflies in one of two ways, by piercing the whitefly body with the ovipositor and laying an egg or by piercing the body and feeding on host fluids. The effects of food deprivation on host-feeding and parasitizing capacity of the whitefly parasitoids Eretmocerus melanoscutus and Encarsia formosa (Hymenoptera: Aphelinidae) were determined in this study. We investigated the effects of various food-deprivation durations (0, 3, 6, 10, and 24 h, and 20% honey solution offered) before being released on the host mortality and parasitism by these species, using fourth-instar Bemisia tabaci (Homoptera: Aleyrodidae) nymphs as test hosts. Er. melanoscutus that were food deprived for 6 h fed on more hosts than those that were food deprived for 0 and 10 h and those that were fed only on honey solution. En. formosa was less sensitive to food deprivation, there being no significant changes in host feeding and parasitism. These species' differences were further confirmed by using third instars of B. tabaci, and both parasitoid species that were food deprived for 6 h fed on more hosts and parasitized similar or more hosts than those that were not food deprived. We also confirmed that Er. melanoscutus that were food deprived for 6 h killed significantly more whiteflies by host feeding and parasitism combined than the nonfood-deprived Er. melanoscutus. However, there were no significant differences in longevity between food-deprived and nonfood-deprived parasitoids of either species. We concluded that the effectiveness of Er. melanoscutus to biological control whitefly nymphs could be improved by starving them for 6 h prior to release. PMID:20550806

  5. Effects of forest spatial structure on insect outbreaks: insights from a host-parasitoid model.

    Science.gov (United States)

    Hughes, Josie S; Cobbold, Christina A; Haynes, Kyle; Dwyer, Greg

    2015-05-01

    Understanding how cycles of forest-defoliating insects are affected by forest destruction is of major importance for forest management. Achieving such an understanding with data alone is difficult, however, because population cycles are typically driven by species interactions that are highly nonlinear. We therefore constructed a mathematical model to investigate the effects of forest destruction on defoliator cycles, focusing on defoliator cycles driven by parasitoids. Our model shows that forest destruction can increase defoliator density when parasitoids disperse much farther than defoliators because the benefits of reduced defoliator mortality due to increased parasitoid dispersal mortality exceed the costs of increased defoliator dispersal mortality. This novel result can explain observations of increased outbreak duration with increasing forest fragmentation in forest tent caterpillar populations. Our model also shows that larger habitat patches can mitigate habitat loss, with clear implications for forest management. To better understand our results, we developed an approximate model that shows that defoliator spatial dynamics can be predicted from the proportion of dispersing animals that land in suitable habitat. This approximate model is practically useful because its parameters can be estimated from widely available data. Our model thus suggests that forest destruction may exacerbate defoliator outbreaks but that management practices could mitigate such effects. PMID:25905513

  6. Effect of host change on demographic fitness of the parasitoid, Trichogramma brassicae.

    Science.gov (United States)

    Iranipour, Shahzad; Vaez, Nahid; Ghanbalani, Ghadir Nouri; Zakaria, Rasoul Asghari; Mashhadi Jafarloo, Mohammad

    2010-01-01

    Trichogramma brassicae (Bezdenko) is the most important species of Trichogramma parasitoids in Iran. The cotton bollworm, Helicoverpa armigera (Hubner) is a polyphagous insect pest that attacks many crops including cotton, maize, soybean, tomato, etc. The bollworm egg is a suitable target for many Trichogramma species. Factitious hosts such as eggs of the flour moth, Anagasta kuehniella (Zeller) and cereal moth, Sitotroga cerealella (Hubner) are used for mass rearing purposes. But a problem that arises sometimes in laboratory cultures is the development of a tendency toward laboratory hosts following a few generations rearing with them. This may tend to a low efficiency on target pest in field conditions. In this study the possibility of declining efficiency of the parasitoid on target pest by developing such a preference to alternative hosts in previous generations were investigated when the flour moth or cereal moth uses as laboratory host. Two generations of T. brassicae were reared on each of the mentioned hosts and then transferred to H. armigera eggs for two further generations. The intrinsic rate of natural increase as well as other life table parameters were used for monitoring fitness of the parasitoid at successive generations. Even generations were included to determine if previously rearing host affected parasitoid performance. Results revealed that host shift from cereal moth to bollworm caused a sudden fall in population growth parameters (both intrinsic rate of natural increase and net replacement rate). Further rearing on bollworm eggs led to a relapse in both parameters. No similar effect was observed in cultures initiated with the flour moth. As a whole, cereal moth was a more suitable host than flour moth. PMID:20673197

  7. Effects of Instructor Attractiveness on Learning.

    Science.gov (United States)

    Westfall, Richard; Millar, Murray; Walsh, Mandy

    2016-01-01

    Although a considerable body of research has examined the impact of student attractiveness on instructors, little attention has been given to the influence of instructor attractiveness on students. This study tested the hypothesis that persons would perform significantly better on a learning task when they perceived their instructor to be high in physical attractiveness. To test the hypothesis, participants listened to an audio lecture while viewing a photograph of instructor. The photograph depicted either a physically attractive instructor or a less attractive instructor. Following the lecture, participants completed a forced choice recognition task covering material from the lecture. Consistent with the predictions; attractive instructors were associated with more learning. Finally, we replicated previous findings demonstrating the role attractiveness plays in person perception. PMID:27410051

  8. PHYSIOLOGICAL EFFECTS OF RESVERATROL AND COUMARIC ACID ON TWO MAJOR GROUNDNUT PESTS AND THEIR EGG PARASITOID BEHAVIOR.

    Science.gov (United States)

    Sambangi, Pratyusha; Rani, Pathipati Usha

    2016-04-01

    Groundnut, Arachis hypogea L., is one of the plant species that synthesizes phenolic compounds, resveratrol and coumaric acid. They are induced as a defense strategy in plant in response to feeding lepidopterans. The present study investigated the role of resveratrol and coumaric acid in producing antiherbivore effects as a direct defense against two major groundnut pests, Spodoptera litura F. and Amsacta albistriga W., and in indirect defense by attracting the egg parasitoid Trichogramma chilonis Ishii under laboratory conditions. The phenolic compounds deterred the feeding of both pests and caused reduction in the larval weights in a dose-dependent manner in leaf disk bioassays. Antioxidant mechanisms of larvae fed with these phenols were measured by estimating the activities of superoxide dismutase (SOD), ascorbate peroxidase (APOX), and catalase (CAT). Enzyme activities increased significantly in experimental larvae, more so in resveratrol-treated than in coumaric acid treated larvae. Feeding larvae with resveratrol and coumaric acid resulted in enhanced activities of detoxifying enzymes, carboxyl esterase (EST), and glutathione-S-transferase (GST) in the midgut tissues of both species, indicating the toxic nature of these compounds. Trichogramma chilonis was more attracted toward coumaric acid treatments in Y-olfactometer tests than to resveratrol. This study contributes to the understanding of the roles of resveratrol and coumaric acid in direct as well as indirect defense, we infer a possible utilization of these compounds in alternate measures of groundnut pest control in future. PMID:26890503

  9. Habitat amount modulates the effect of patch isolation on host-parasitoid interactions

    Directory of Open Access Journals (Sweden)

    Valérie eCoudrain

    2014-06-01

    Full Text Available 1.Habitat amount and patch isolation are important determinants of biodiversity and ecosystem functioning. We studied the separate and interactive effects of these two components of habitat fragmentation on host-parasitoid interactions in a replicated landscape-scale study. 2.We used trap-nesting solitary bees, wasps and their natural enemies as study system. We exposed trap nests in 30 tree patches in agricultural landscapes in northern Switzerland. Study sites were either (i adjacent to forest (adjacent, (ii distant from forest but connected through woody elements (connected or (iii distant from forest with no connecting woody elements (isolated. Independent of the three levels of isolation, the amount of woody habitat in the landscapes covered a gradient from 4 to 74%. 3.Host and parasitoid species richness increased with the amount of habitat in the landscape and was strongly reduced at isolated compared to adjacent and connected sites. Loss of host species richness was 21% at isolated compared to non-isolated sites, whereas parasitoid species richness decreased by 68%, indicating that the higher trophic level was more adversely affected by isolation. Most importantly, habitat amount and isolation had a pronounced interactive effect on parasitism: while isolation resulted in a strong decrease in parasitism in landscapes with low habitat amount, this effect was mitigated by high habitat amount. These interactive effects were consistent across the three years of the study. 4.The observed interplay between habitat amount and patch isolation may explain the often conflicting results in the habitat fragmentation literature and should be considered in future research on multitrophic communities and ecosystem functioning in fragmented landscapes.

  10. Parasitoid load affects plant fitness in a tritrophic system

    OpenAIRE

    Smallegange, R. C.; Loon, van, J.Th.; Blatt, S. E.; Harvey, J. A.; Dicke, M.

    2008-01-01

    Plants attacked by herbivorous insects emit volatile compounds that attract predators or parasitoids of the herbivores. Plant fitness increases when these herbivorous insects are parasitized by solitary parasitoids, but whether gregarious koinobiont parasitoids also confer a benefit to plant fitness has been disputed. We investigated the relationship between parasitoid load of the gregarious Cotesia glomerata (L.) (Hymenoptera: Braconidae), food consumption by larvae of their host Pieris bras...

  11. Lethal and sublethal effects of lufenuron on sugarcane borer Diatraea flavipennella and its parasitoid Cotesia flavipes.

    Science.gov (United States)

    Fonseca, Ana Paula Pereira; Marques, Edmilson Jacinto; Torres, Jorge Braz; Silva, Liliane Marques; Siqueira, Herbert Álvaro Abreu

    2015-11-01

    The combination of chemical and biological controls is a historic goal of integrated pest management, but has rarely been achieved due to lethal and sublethal impact of insecticides on natural enemies altering their performance. In this context, the susceptibility of the yellow sugarcane borer, Diatraea flavipennella (Lepidoptera: Crambidae), to the insect growth regulator lufenuron and the consequent effects upon its endoparasitoid Cotesia flavipes (Hymenoptera: Braconidae) encountering exposed but surviving larvae were studied. Neonate and 10-day-old larvae were subjected to one of seven concentrations of lufenuron (1.56, 3.12, 6.25, 12.5, 25.0, 50.0 and 100 mg a.i./L). Further, effects of lufenuron to the host larvae and to the parasitoid were assessed using low lethal LC20 and LC50. Lufenuron at concentrations up to 12.5 mg a.i./L allowed partial survival of borer larvae; and concentrations over 12.5 mg a.i./L caused 100 % larval mortality before pupation in both ages. Neonate larvae exhibited lower pupal weights only at concentrations 12.5 mg a.i./L; while 10-day-old larvae treated with the LC50 exhibited delayed development. Egg viability was reduced for adult borers from surviving larvae of both ages treated with low lethal concentrations. The parasitoid C. flavipes successfully parasitized surviving low lethal treated larvae. Among the studied life history characteristics of C. flavipes, only a delayed development was observed. The results showed that lufenuron can be effective against D. flavipennella at concentrations over 25 mg a.i./L, and that surviving larvae can be successfully parasitized by C. flavipes. The insecticide lufenuron and the parasitoid C. flavipes seem to be compatible for sugarcane borer control. PMID:26250937

  12. Effects of spirotetramat on Aonidiella aurantii (Homoptera: Diaspididae) and its parasitoid, Aphytis melinus (Hymenoptera: Aphelinidae).

    Science.gov (United States)

    Garcerá, Cruz; Ouyang, Yuling; Scott, Sara J; Moltó, Enrique; Grafton-Cardwell, Elizabeth E

    2013-10-01

    Laboratory and field studies were conducted to measure the effects of spirotetramat on life stages of California red scale, Aonidiella aurantii (Maskell), and a primary parasitoid, Aphytis melinus DeBach. Organophosphate-resistant and -susceptible populations responded similarly to spirotetramat, suggesting there is no cross-resistance between these insecticide classes. First and second instar male and female A. aurantii were 10- and 32-fold more susceptible to spirotetramat (LC50 = 0.1-0.2 ppm) compared with early third (LC50 = 1.5 ppm) and late third instar females (LC50 = 5.3 ppm). The LC99 value indicated that late stage third instar females would not be fully controlled by a field rate of spirotetramat; however, spirotetramat would reduce their fecundity by 89%. Field applications of spirotetramat in two water volumes and using two adjuvants (oil and a nonionic spray adjuvant) showed similar reduction in A. aurantii numbers, even though the higher water volume demonstrated more complete coverage. These data suggest that this foliarly applied systemic insecticide can be applied in as little as 2,340 liters/ha of water volume, minimizing application costs, and that the two adjuvants acted similarly. The endoparasitoid, A. melinus, was unaffected by the field rate of spirotetramat when it was applied to the host when the parasitoid was in the egg or larval stage. Adult A. melinus showed 2 wk of moderate reductions in survival when exposed to leaves with field-weathered residues. Spirotetramat is an integrated pest management compatible insecticide, effective in reducing A. aurantii stages and allowing survival of its primary parasitoid A. melinus. PMID:24224255

  13. Differential Effects of Pesticide Applications on Liriomyza huidobrensis (Diptera: Agromyzidae) and its Parasitoids on Pea in Central Kenya.

    Science.gov (United States)

    Guantai, M M; Ogol, C P K O; Salifu, D; Kasina, J M; Akutse, K S; Fiaboe, K K M

    2015-04-01

    Three Liriomyza species [Liriomyza huidobrensis (Blanchard), Liriomyza trifolii (Burgess), and Liriomyza sativae Blanchard] have been reported as the most important leafminer pests in vegetable production systems in Africa. In Kenya, farmers rely on indiscriminate synthetic insecticides use. On-farm field investigations were set up at three different locations (Sagana, Kabaru, and Naromoru) in central Kenya to determine the effect of pesticide application on the abundance of leafminers and their parasitoids under three management practices, namely: farmer practice (FP), reduced pesticide use (RP), and a control with no use of pesticides (CO). In addition, laboratory experiments were designed to test the effect of commonly used pesticides in pea production systems in central Kenya--Dimethoate, Dynamec, Thunder, Cyclone, Bestox, Folicur, Milraz, and Bulldock--on L. huidobrensis and two of its parasitoids, Diglyphus isaea Walker and Phaedrotoma scabriventris Nixon. The mean numbers of leafminer flies in control treatment were higher than in RP and FP in both first and second seasons across all sites, but RP and FP did not differ significantly. Parasitoid numbers were very low and there was no much variation between treatments at each location in both first and second seasons. No significant differences were observed between the three management practices with regards to the yield measurements. In the laboratory, the estimated LD50 values for L. huidobrensis larvae were all more than two times higher than the recommended dosages, while the LD50 of adults were below the recommended dosages. The estimated LD50 values for the parasitoids were much lower than recommended dosages for all pesticides except Thunder. This study, therefore, demonstrates that the pesticides currently used do not control the Liriomyza leafminer larvae that constitute the most destructive stage of the pest, but are rather detrimental to their parasitoids. In addition, the current low level of

  14. Combined Non-Target Effects of Insecticide and High Temperature on the Parasitoid Bracon nigricans.

    Science.gov (United States)

    Abbes, Khaled; Biondi, Antonio; Kurtulus, Alican; Ricupero, Michele; Russo, Agatino; Siscaro, Gaetano; Chermiti, Brahim; Zappalà, Lucia

    2015-01-01

    We studied the acute toxicity and the sublethal effects, on reproduction and host-killing activity, of four widely used insecticides on the generalist parasitoid Bracon nigricans (Hymenoptera: Braconidae), a natural enemy of the invasive tomato pest, Tuta absoluta (Lepidoptera: Gelechiidae). Laboratory bioassays were conducted applying maximum insecticide label rates at three constant temperatures, 25, 35 and 40°C, considered as regular, high and very high, respectively. Data on female survival and offspring production were used to calculate population growth indexes as a measure of population recovery after pesticide exposure. Spinetoram caused 80% mortality at 25°C and 100% at higher temperatures, while spinosad caused 100% mortality under all temperature regimes. Cyantraniliprole was slightly toxic to B. nigricans adults in terms of acute toxicity at the three temperatures, while it did not cause any sublethal effects in egg-laying and host-killing activities. The interaction between the two tested factors (insecticide and temperature) significantly influenced the number of eggs laid by the parasitoid, which was the lowest in the case of females exposed to chlorantraniliprole at 35°C. Furthermore, significantly lower B. nigricans demographic growth indexes were estimated for all the insecticides under all temperature conditions, with the exception of chlorantraniliprole at 25°C. Our findings highlight an interaction between high temperatures and insecticide exposure, which suggests a need for including natural stressors, such as temperature, in pesticide risk assessments procedures. PMID:26382245

  15. Effects of partner beauty on opposite-sex attractiveness judgments.

    Science.gov (United States)

    Little, Anthony C; Caldwell, Christine A; Jones, Benedict C; DeBruine, Lisa M

    2011-12-01

    Many studies show mate choice copying effects on mate preferences in non-human species in which individuals follow or copy the mate choices of same-sex conspecifics. Recent studies suggest that social learning also influences mate preferences in humans. Studies on heterosexual humans have focused on rating the attractiveness of potential mates (targets) presented alongside individuals of the opposite sex to the target (models). Here, we examined several different types of pairing to examine how specific social learning is to mate preferences. In Study 1, we replicated a previous effect whereby target faces of the opposite sex to the subject were rated as more attractive when paired with attractive than unattractive partner models of the same sex as the subject. Using the same paired stimuli, Study 2 demonstrated no effect of a paired model if subjects were asked to rate targets who were the same sex as themselves. In Study 3, we used pairs of the same sex, stating the pair were friends, and subjects rated targets of the opposite sex to themselves. Attractive models decreased targets' attractiveness, opposite to the effect in Study 1. Finally, Study 4 examined if attractive versus unattractive non-face stimuli might influence attraction. Unlike in Study 1, pairing with attractive stimuli either had no effect or decreased the attractiveness of paired target face images. These data suggest that social transmission of preferences via pairing with attractive/unattractive images is relatively specific to learning about mate preferences but does not influence attractiveness judgments more generally. PMID:21901646

  16. Effects of Transgenic Cry 1 Ac plus CpTI Cotton on the Bioecology of Main Parasitoids in Laboratory Studies

    Institute of Scientific and Technical Information of China (English)

    CUI Jin-jie; VANDER Weft Wopke; MA Yah; LUO Jun-yu

    2008-01-01

    @@ Effects of transgenic CrylAc plus CpTI cotton (double genes cotton) on development of main parasitoids were studied in the laboratory.Compared with the traditional cotton,the differences of the moulting rate and adult weight of cotton aphid-Aphydius from double gene cotton field were not obvious.

  17. Habitats as complex odour environments: how does plant diversity affect herbivore and parasitoid orientation?

    Directory of Open Access Journals (Sweden)

    Nicole Wäschke

    Full Text Available Plant diversity is known to affect success of host location by pest insects, but its effect on olfactory orientation of non-pest insect species has hardly been addressed. First, we tested in laboratory experiments the hypothesis that non-host plants, which increase odour complexity in habitats, affect the host location ability of herbivores and parasitoids. Furthermore, we recorded field data of plant diversity in addition to herbivore and parasitoid abundance at 77 grassland sites in three different regions in Germany in order to elucidate whether our laboratory results reflect the field situation. As a model system we used the herb Plantago lanceolata, the herbivorous weevil Mecinus pascuorum, and its larval parasitoid Mesopolobus incultus. The laboratory bioassays revealed that both the herbivorous weevil and its larval parasitoid can locate their host plant and host via olfactory cues even in the presence of non-host odour. In a newly established two-circle olfactometer, the weeviĺs capability to detect host plant odour was not affected by odours from non-host plants. However, addition of non-host plant odours to host plant odour enhanced the weeviĺs foraging activity. The parasitoid was attracted by a combination of host plant and host volatiles in both the absence and presence of non-host plant volatiles in a Y-tube olfactometer. In dual choice tests the parasitoid preferred the blend of host plant and host volatiles over its combination with non-host plant volatiles. In the field, no indication was found that high plant diversity disturbs host (plant location by the weevil and its parasitoid. In contrast, plant diversity was positively correlated with weevil abundance, whereas parasitoid abundance was independent of plant diversity. Therefore, we conclude that weevils and parasitoids showed the sensory capacity to successfully cope with complex vegetation odours when searching for hosts.

  18. Tritrophic effects of xanthotoxin on the polyembryonic parasitoid Copidosoma sosares (Hymenoptera: Encyrtidae).

    Science.gov (United States)

    Lampert, Evan C; Zangerl, Arthur R; Berenbaum, May R; Ode, Paul J

    2008-06-01

    Plant chemistry can have deleterious effects on insect parasitoids, which include the reduction in body size, increased development time, and increased mortality. We examined the effects of xanthotoxin, a linear furanocoumarin, on the polyembryonic encyrtid wasp Copidosoma sosares, a specialist parasitoid that attacks the parsnip webworm, Depressaria pastinacella, itself a specialist on furanocoumarin-producing plants. Furanocoumarins, allelochemicals abundant in the Apiaceae and Rutaceae, are toxic to a wide range of herbivores. In this study, we reared parasitized webworms on artificial diets containing no xanthotoxin (control) or low or high concentrations of xanthotoxin. Clutch sizes of both male and female C. sosares broods were more than 20% smaller when they developed in hosts fed the diet containing high concentrations of xanthotoxin. Xanthotoxin concentration in the artificial diet had no effect on the development time of C. sosares, nor did it have an effect on the body size (length of hind tibia) of individual adult male and female C. sosares in single-sex broods. Webworms fed artificial diets containing low or high concentrations of xanthotoxin were not significantly smaller, and their development time was similar to that of webworms fed a xanthotoxin-free diet. Mortality of webworms was not affected by xanthotoxin in their artificial diet. Therefore, dietary xanthotoxin did not appear to affect C. sosares via impairment of host health. However, unmetabolized xanthotoxin was found in D. pastinacella hemolymph where C. sosares embryos develop. Hemolymph concentrations were fourfold greater in webworms fed the high-xanthotoxin-containing diet than in webworms fed the low-xanthotoxin-containing diet. We failed to detect any xanthotoxin metabolism by either C. sosares embryos or precocious larvae. Therefore, the observed tritrophic effects of xanthotoxin are likely to be due to the effects of xanthotoxin after direct contact in the hemolymph rather than to

  19. Effects of selected insecticides on Diadegma semiclausum(Hymenoptera: Ichneumonidae) and Oomyzus sokolowskii (Hymenoptera: Eulophidae), parasitoids of Plutella xylostella (Lepidoptera: Plutellidae)

    Institute of Scientific and Technical Information of China (English)

    MUHAMMADHASEEB; HIROSHIAMANO; TONG-XIANLIU

    2005-01-01

    act Field doses of six selected insecticides were tested against the immature (pupae)and mature (adult) stages of Diadegma semiclausum (Hellén) and Oomyzus sokolowskii(Kurdjumov), parasitoids of the diamondback moth, Plutella xylostella (L.). Effects ofcontact toxicity (direct spraying) of the six insecticides on emergence of parasitoids were found negligible on both species except permethrin which caused 37.5% mortality. All adults of both parasitoid species died 24 hours after exposure to chlorfenapyr, emamectin benzoate and permethrin. In contrast, the three insect growth regulators (IGRs), chlorfluazuron,flufenoxuron and teflubenzuron, were found harmless to both species, and adult mortality of both parasitoid species was 0-16.7%. However, parasitism by the females of both parasitoid species was severely impaired when the females were offered the three IGR diluted solutions for 24 hours. Effects of oral toxicities of the IGRs on longevity of both parasitoids after 12 hours exposure were found to be significandy different between males and females. Compatibility of tested insecticides with D. semiclausum and O. sokolowskii and integration of compatible insecticides with these parasitoids in integrated pest management programs of crucifers are discussed.

  20. Multitrophic effects of experimental changes in plant diversity on cavity-nesting bees, wasps, and their parasitoids.

    Science.gov (United States)

    Ebeling, Anne; Klein, Alexandra-Maria; Weisser, Wolfgang W; Tscharntke, Teja

    2012-06-01

    Plant diversity changes can impact the abundance, diversity, and functioning of species at higher trophic levels. We used an experimental gradient in grassland plant diversity ranging from 1 to 16 plant species to study multitrophic interactions among plants, cavity-nesting bees and wasps, and their natural enemies, and analysed brood cell density, insect diversity (species richness), and bee and wasp community similarity over two consecutive years. The bee and wasp communities were more similar among the high (16 species) diversity plots than among plots of the lower diversity levels (up to 8 species), and a more similar community of bees and wasps resulted in a more similar community of their parasitoids. Plant diversity, which was closely related to flower diversity, positively and indirectly affected bee diversity and the diversity of their parasitoids via increasing brood cell density of bees. Increasing plant diversity directly led to higher wasp diversity. Parasitism rates of bees and wasps (hosts) were not affected by plant diversity, but increased with the diversity of their respective parasitoids. Decreases in parasitism rates of bees arose from increasing brood cell density of bees (hosts), whereas decreasing parasitism rates of wasps arose from increasing wasp diversity (hosts). In conclusion, decreases in plant diversity propagated through different trophic levels: from plants to insect hosts to their parasitoids, decreasing density and diversity. The positive relationship between plant diversity and the community similarity of higher trophic levels indicates a community-stabilising effect of high plant diversity. PMID:22120706

  1. Quality of the Exotic Parasitoid Cotesia flavipes (Hymenoptera: Braconidae) Does Not Show Deleterious Effects after Inbreeding for 10 Generations.

    Science.gov (United States)

    Trevisan, Maíra; De Bortoli, Sergio A; Vacari, Alessandra M; Laurentis, Valéria L; Ramalho, Dagmara G

    2016-01-01

    Although the parasitoid Cotesia flavipes (Cameron) has proven effective in controlling sugarcane borer Diatraea saccharalis (Fabricius) for many years, concern has arisen over the quality of individuals produced at large scales. The parasitoid has been reared in laboratories in Brazil for more than 40 years, with no new introductions of new populations during that period. Since the quality of the parasitoids was not verified at the time of the species' introduction in Brazil, we do not know if there has been any reduction in quality so far. However, it is possible to determine whether the parasitoid could reduce in quality in future generations. Thus, the objective of this research was to assess the quality of these insects over 10 generations and look for evidence of any loss in quality. We used two populations: one from a biofactory that has been maintained in the laboratory for over 40 years, and an inbred laboratory population. Both were bred, and compared for 10 generations. We wanted to determine what happened to the quality of the parasitoid after 10 generations in an extreme inbreeding situation. To assure inbreeding, newly emerged females were forced to mate with a sibling. Individual females were then allowed to parasitize larvae of D. saccharalis. We performed evaluations for each generation until the tenth generation, and recorded the sex ratio, percentage emergence, number of offspring/females, and longevity of both males and females. Results of the measurements of biological characteristics demonstrated random significant differences between populations; best results were obtained intermittently for both the biofactory population and the inbred population. No significant differences across generations for the same population were observed. Thus, rearing of a C. flavipes population subjected to inbreeding for 10 generations was not sufficient to reveal any deleterious effects of inbreeding. PMID:27509087

  2. Effects of heat shock on resistance to parasitoids and on life history traits in an aphid/endosymbiont system.

    Science.gov (United States)

    Cayetano, Luis; Vorburger, Christoph

    2013-01-01

    Temperature variation is an important factor determining the outcomes of interspecific interactions, including those involving hosts and parasites. This can apply to variation in average temperature or to relatively short but intense bouts of extreme temperature. We investigated the effect of heat shock on the ability of aphids (Aphis fabae) harbouring protective facultative endosymbionts (Hamiltonella defensa) to resist parasitism by Hymenopteran parasitoids (Lysiphlebus fabarum). Furthermore, we investigated whether heat shocks can modify previously observed genotype-by-genotype (G x G) interactions between different endosymbiont isolates and parasitoid genotypes. Lines of genetically identical aphids possessing different isolates of H. defensa were exposed to one of two heat shock regimes (35°C and 39°C) or to a control temperature (20°C) before exposure to three different asexual lines of the parasitoids. We observed strong G x G interactions on parasitism rates, reflecting the known genetic specificity of symbiont-conferred resistance, and we observed a significant G x G x E interaction induced by heat shocks. However, this three-way interaction was mainly driven by the more extreme heat shock (39°C), which had devastating effects on aphid lifespan and reproduction. Restricting the analysis to the more realistic heat shock of 35°C, the G x G x E interaction was weaker (albeit still significant), and it did not lead to any reversals of the aphid lines' susceptibility rankings to different parasitoids. Thus, under conditions feasibly encountered in the field, the relative fitness of different parasitoid genotypes on hosts protected by particular symbiont strains remains mostly uncomplicated by heat stress, which should simplify biological control programs dealing with this system. PMID:24143175

  3. Quality of the Exotic Parasitoid Cotesia flavipes (Hymenoptera: Braconidae) Does Not Show Deleterious Effects after Inbreeding for 10 Generations

    Science.gov (United States)

    Trevisan, Maíra; De Bortoli, Sergio A.; Vacari, Alessandra M.; Laurentis, Valéria L.; Ramalho, Dagmara G.

    2016-01-01

    Although the parasitoid Cotesia flavipes (Cameron) has proven effective in controlling sugarcane borer Diatraea saccharalis (Fabricius) for many years, concern has arisen over the quality of individuals produced at large scales. The parasitoid has been reared in laboratories in Brazil for more than 40 years, with no new introductions of new populations during that period. Since the quality of the parasitoids was not verified at the time of the species' introduction in Brazil, we do not know if there has been any reduction in quality so far. However, it is possible to determine whether the parasitoid could reduce in quality in future generations. Thus, the objective of this research was to assess the quality of these insects over 10 generations and look for evidence of any loss in quality. We used two populations: one from a biofactory that has been maintained in the laboratory for over 40 years, and an inbred laboratory population. Both were bred, and compared for 10 generations. We wanted to determine what happened to the quality of the parasitoid after 10 generations in an extreme inbreeding situation. To assure inbreeding, newly emerged females were forced to mate with a sibling. Individual females were then allowed to parasitize larvae of D. saccharalis. We performed evaluations for each generation until the tenth generation, and recorded the sex ratio, percentage emergence, number of offspring/females, and longevity of both males and females. Results of the measurements of biological characteristics demonstrated random significant differences between populations; best results were obtained intermittently for both the biofactory population and the inbred population. No significant differences across generations for the same population were observed. Thus, rearing of a C. flavipes population subjected to inbreeding for 10 generations was not sufficient to reveal any deleterious effects of inbreeding. PMID:27509087

  4. Screening and field evaluation of synthetic plant volatiles as attractants for Anagrus nilaparvatae Pang et Wang,an egg parasitoid of rice planthoppers%稻飞虱卵期寄生蜂稻虱缨小蜂引诱剂的筛选与田间试验

    Institute of Scientific and Technical Information of China (English)

    汪鹏; 娄永根

    2013-01-01

    植食性昆虫的天敌能够利用虫害诱导的挥发物进行有效的寄主或猎物定位.为了开发稻飞虱卵期天敌稻虱缨小蜂Anagrus nilaparvatae Pang et Wang的引诱剂,分别在室内和室外检测了多种褐飞虱诱导的水稻挥发物组分对褐飞虱卵期天敌稻虱缨小蜂的引诱作用.Y型嗅觉仪实验结果表明,5种单一化合物,Z-3-己烯乙酸酯,1-戊烯基-3-醇,Z-3-己烯醛,芳樟醇和水杨酸甲酯,以及3种混合物,水杨酸甲酯+Z-3-己烯醛,Z-3-己烯醛+Z-3-己烯乙酸酯+芳樟醇,水杨酸甲酯+Z-3-己烯醛+Z-3-己烯乙酸酯+芳樟醇,对稻虱缨小蜂具有明显引诱作用.田间试验表明,3种单一化合物,Z-3-己烯乙酸酯,Z-3-己烯醛和芳樟醇,以及一种混合物,水杨酸甲酯+Z-3-己烯醛+ Z-3-己烯乙酸酯+芳樟醇,能明显提高稻虱缨小蜂对褐飞虱卵的寄生作用.这些结果对于改善褐飞虱治理具有重要的意义.%Natural enemies of herbivores can effectively locate their hosts or prey by perceiving herbivore-induced plant volatiles.In order to develop attractants for Anagrus nilaparvatae Pang et Wang,an egg parasitoid of rice planthoppers,we tested the attractiveness of synthetic rice volatiles induced by the rice brown planthopper (BPH) Nilaparvata lugens (St(a)l) to the parasitoid in both laboratory and field.In the laboratory,using a Y-tube olfactometer,we found that five compounds(Z-3-hexenyl acetate,1-penten-3-ol,Z-3-hexenal,linalool and MeSA) attract the parasitoid.Moreover,A.nilapareatae was strongly attracted by three mixtures,one of MeSA plus Z-3-hexenal,one containing Z-3-hexenal,Z-3-hexenyl acetate and linalool,and one containing MeSA,Z-3-hexenal,Z-3-hexenyl acetate and linalool.Field experiments demonstrated that the parasitism of BPH eggs by the parasitoid was significantly increased on plants that received a septa containing one of the 3 chemicals (Z-3-hexenal,Z-3-hexenyl acetate,linalool) or the mixture containing MeSA,Z-3-hexenal

  5. The Effects of Attractiveness and Status on Personality Evaluation

    OpenAIRE

    Stefano Tartaglia; Chiara Rollero

    2015-01-01

    Research on personality has shown that perceiving a person as attractive fosters positive expectations about his/her personal characteristics. Literature has also demonstrated a significant link between personality traits and occupational achievement. Present research examines the combined effects of attractiveness, occupational status, and gender on the evaluation of others’ personality, according to the Big Five model. The study consisted of a 2 (Attractiveness: High vs. Low) x 2 (occupatio...

  6. Host diapause status and host diets augmented with cryoprotectants enhance cold hardiness in the parasitoid Nasonia vitripennis.

    Science.gov (United States)

    Li, Yuyan; Zhang, Lisheng; Zhang, Qirui; Chen, Hongyin; Denlinger, David L

    2014-11-01

    Boosting cold hardiness in parasitoids is a goal that is particularly attractive for increasing shelf life and shipment of biological control agents. In the experiments reported here we use the parasitoid Nasonia vitripennis as a model to evaluate manipulations that may be capable of enhancing the wasp's cold tolerance. We altered the parasitoid's cold tolerance by manipulating the wasp's diapause status, the diapause status of the host fly (Sarcophaga crassipalpis), and the diet of the host. Larval diapause in N. vitripennis dramatically increased cold tolerance and the diapause status of the host also exerted a positive, although less dramatic, effect. Augmenting the host fly's diet with supplements of putative cryoprotectants (alanine, proline and glycerol) enhanced cold tolerance in parasitoids that fed on the flies, thus indicating a tri-trophic effect on parasitoid cold tolerance. The most pronounced improvement in cold tolerance was noted in parasitoids fed on fly hosts that had received a diet augmented with proline. These results suggest mechanisms that could be exploited for enhancement of cold tolerance in parasitoids of commercial interest. PMID:25158026

  7. Effects of switching behavior for the attraction on pedestrian dynamics

    CERN Document Server

    Kwak, Jaeyoung; Luttinen, Tapio; Kosonen, Iisakki

    2014-01-01

    Walking is a fundamental activity of our daily life not only for moving to other places but also for interacting with surrounding environment. While walking on the streets, pedestrians can be aware of attractions like shopping windows. They can be influenced by the attractions and some of them might shift their attention towards the attractions, namely switching behavior. As a first step to incorporate the switching behavior, this study investigates collective effects of switching behavior for an attraction by developing a behavioral model. Numerical simulations exhibit different patterns of pedestrian behavior depending on the strength of the social influence and the average length of stay. When the social influence is strong along with a long length of stay, a saturated phase can be defined at which all the pedestrians have visited the attraction. If the social influence is not strong enough, an unsaturated phase appears where one can observe that some pedestrians head for the attraction while others walk i...

  8. Control potential of three hymenopteran parasitoid species against the bean weevil in stored beans: The effect of adult parasitoid nutrition on longevity and progeny production

    NARCIS (Netherlands)

    Schmale, I.; Wäckers, F.L.; Cardona, C.; Dorn, S.

    2001-01-01

    We evaluated the longevity and progeny production of three hymenopteran parasitoids of Acanthoscelides obtectus (Say) (Coleoptera: Bruchidae) when kept with or without food sources. In absence of adult food, Dinarmus basalis Ashm. (Pteromalidae) and Heterospilus prosopidis (Viereck) (Braconidae) liv

  9. Control potential of three hymenopteran parasitoid species against the bean weevil in stored beans: the effect of adult parasitoid nutrition on longevity and progeny production

    NARCIS (Netherlands)

    Schmale, I.; Wäckers, F.L.; Cardona, C.; Dorn, S.

    2001-01-01

    We evaluated the longevity and progeny production of three hymenopteran parasitoids of Acanthoscelides obtectus (Say) (Coleoptera: Bruchidae) when kept with or without food sources. In absence of adult food, Dinarmus basalis Ashm. (Pteromalidae) and Heterospilus prosopidis (Viereck) (Braconidae) liv

  10. Relationship of Physical Attractiveness to Students' Ratings of Teaching Effectiveness.

    Science.gov (United States)

    O'Reilly, Maria T.

    1987-01-01

    A study found that the physical attractiveness of a dental school teacher affected the student's opinion of teaching effectiveness, regardless of the student's sex, with effectiveness ratings correlating with pleasing appearance. (MSE)

  11. The Perceived Relationship between Physical Attractiveness and Social Influence Effectiveness.

    Science.gov (United States)

    Longo, Laura C.; Ashmore, Richard D.

    The power of beauty has been contemplated by writers, poets, and philosophers for centuries. The link between the target physical attractiveness and perceived social influence effectiveness has not been directly and systematically investigated. The goal of this study was to assess whether physically attractive (versus unattractive) individuals are…

  12. Effects of Type of Information Upon Interpersonal Attraction

    Science.gov (United States)

    Duck, Steven W.; Craig, Gordon

    1975-01-01

    Two experiments are reported: one in which presentation of external information about a stranger evoked significantly higher attraction ratings than available psychological information; and a second where similarity of Subject and Other on external characteristics had greater effects upon attraction scores than did similarity of psychological…

  13. Effects of root herbivory on pyrrolizidine alkaloid content and aboveground plant-herbivore-parasitoid interactions in Jacobaea vulgaris

    OpenAIRE

    O. Kostenko; Mulder, P.P.J.; Bezemer, T.M.

    2013-01-01

    The importance of root herbivory is increasingly recognized in ecological studies, and the effects of root herbivory on plant growth, chemistry, and performance of aboveground herbivores have been relatively well studied. However, how belowground herbivory by root feeding insects affects aboveground parasitoid development is largely unknown. In this study, we examined the effects of root herbivory by wireworms (Agriotes lineatus) on the expression of primary and secondary compounds in the lea...

  14. Effects of some insecticides on the adult emergence of sunn pest egg parasitoids Trissolcus spp. (Hymenoptera: Scelionidae)

    OpenAIRE

    BABAROĞLU, Numan E.; UĞUR, Avni

    2010-01-01

    In this study, the effects of most commonly used insecticides, Fenitrothion and Zetacypermethrin in order to control sunn pest, the most important pest of cereal to preimaginal stages of egg parasitoid (Trissolcus spp.) of sunn pest were determined under laboratory and field condition between 2003-2005 years. Both EC and ULV formulations of these insecticides was found to be effective with 100 % ratio on adult emergence under laboratory conditions and assessed as harmful. As for fie...

  15. Effects of volatiles from Maruca vitrata larvae and caterpillar-infested flowers of their host plant Vigna unguiculata on the foraging behavior of the parasitoid Apanteles taragamae

    OpenAIRE

    Dannon, A.E.; Tamò, M.; Huis, van, A.; Dicke, M.

    2010-01-01

    The parasitoid wasp Apanteles taragamae is a promising candidate for the biological control of the legume pod borer Maruca vitrata, which recently has been introduced into Benin. The effects of volatiles from cowpea and peabush flowers and Maruca vitrata larvae on host selection behavior of the parasitoid Apanteles taragamae were investigated under laboratory conditions by using a Y-tube olfactometer. Naïve and oviposition-experienced female wasps were given a choice between several odor sour...

  16. Effects of pollen load, parasitoids and the environment on pre-dispersal seed predation in the cleistogamous Ruellia nudiflora.

    Science.gov (United States)

    Munguía-Rosas, Miguel A; Abdala-Roberts, Luis; Parra-Tabla, Víctor

    2013-11-01

    Few studies have simultaneously addressed the effects of biotic and abiotic factors on pre-dispersal seed predation (PSP). Plant-seed predator interactions may be influenced by natural enemies and pollinators (the latter through changes in fruit or seed traits), and the activity of pre-dispersal seed predators and their natural enemies may both be affected by the abiotic environment. Additionally, in the case of cleistogamous plants with fruit dimorphism, PSP may be biased towards larger and more seeded chasmogamous (CH) fruits [relative to the smaller cleistogamous (CL) fruits], and the effects of biotic and abiotic factors may be contingent upon this fruit dimorphism. We studied PSP in the cleistogamous Ruellia nudiflora using a split-plot experimental design and asked the following: (1) is PSP biased towards CH fruits and is there an effect of pollen load on PSP? (2) Do parasitoids influence PSP and is their effect influenced by pollen load or fruit type? And (3) do light and water availability modify PSP and parasitoid effects? PSP was higher for CH relative to CL fruits, and under low water availability it was lower for pollen-supplemented CH fruits relative to open-pollinated CH fruits. Parasitoids were not influenced by abiotic conditions, but their negative effect on PSP was stronger for pollen-supplemented CH fruits. Overall, we show that fruit dimorphism, abiotic factors and natural enemies affect PSP, and that these effects can be non-additive. PMID:23576106

  17. Enhanced stability in host-parasitoid interactions with autoparasitism and parasitoid migration.

    Science.gov (United States)

    Huang, Yunxin; Yang, Nianwan; Qin, Yun; An, Feng; Li, Zhaohua; Wan, Fanghao

    2016-03-21

    Previous studies based on simple non-spatial model have suggested that autoparasitism, in which females develop as primary endoparasitoids of hosts while males develop at the expense of primary parasitoids, stabilizes host-parasitoid steady state. To date, however, how the stabilizing role of autoparasitism would be affected by more complex spatial factors has not been adequately investigated. To address the issue, here we analyzed a spatially extended two-patch host-parasitoid model and compared it with the corresponding non-spatial model. Results showed that in the non-spatial model and the case of autoparasitoid, the host-parasitoid steady states can be unstable if the host׳s intrinsic rate of growth and/or carrying capacity is sufficiently large. However, in the spatially extended two-patch model with parasitoid migration, the unstable host-parasitoid steady states in each local patch may become stable, provided there is certain spatial unevenness in host growth and/or carrying capacity. Therefore, the migration of parasitoid together with spatial unevenness in host growth and/or carrying capacity stabilizes the host-parasitoid interactions. The stabilizing effects are stronger with the host density-dependent migration of parasitoid than with the random migration of parasitoid. In the case of primary parasitoid, the model demonstrated similar stabilizing effects associated with the migration of parasitoid. However, the parameter conditions for stability are much more stringent than in the case of autoparasitoid. We concluded that the stabilizing effects of parasitoid migration and autoparasitism can add to each other, leading to more stable host-parasitoid interactions. PMID:26780647

  18. The sublethal effects of endosulfan on the circadian rhythms and locomotor activity of two sympatric parasitoid species.

    Science.gov (United States)

    Delpuech, Jean-Marie; Bussod, Sophie; Amar, Aurelien

    2015-08-01

    The organochlorine insecticide endosulfan is dispersed worldwide and significantly contributes to environmental pollution. It is an antagonist of the neurotransmitter gamma-aminobutyric acid (GABA), which is also indirectly involved in photoperiodic time measurement. In this study, we show that endosulfan at a dose as low as LC 0.1 modified the rhythm of locomotor activity of two sympatric parasitoid species, Leptopilina boulardi and Leptopilina heterotoma. The insecticide strongly increased the nocturnal activity of both species and synchronized their diurnal activity; these activities were not synchronized under control conditions. Parasitoids are important species in ecosystems because they control the populations of other insects. In this paper, we discuss the possible consequences of these sublethal effects and highlight the importance of such effects in evaluating the consequences of environmental pollution due to insecticides. PMID:25898969

  19. Effects of a broad spectrum and biorational insecticides on parasitoids of the Nantucket pine tip moth (Lepidoptera: Tortricidae).

    Science.gov (United States)

    McCravy, K W; Dalusky, M J; Berisford, C W

    2001-02-01

    We examined effects of aerial application of acephate (Orthene), Bacillus thuringiensis variety kurstaki Berliner (Foray), and tebufenozide (Mimic) on larval/pupal parasitoids of the Nantucket pine tip moth, Rhyacionia frustrana (Comstock), in the southwestern Georgia coastal plain. Parasitism of tip moths in acephate-treated plots was significantly lower than in untreated plots. Bacillus thuringiensis and tebufenozide showed no significant effects on parasitism. A tachinid, Lixophaga mediocris Aldrich, comprised a significantly greater proportion of emerging parasitoids in acephate-treated than in untreated control plots, whereas a chalcidid, Haltichella rhyacioniae Gahan, was less abundant in the acephate-treated plots. Acephate has a negative, but somewhat species-specific, impact on tip moth parasitism. PMID:11233099

  20. The Effect of Physical Attractiveness of Models on Advertising Effectiveness for Male and Female Adolescents

    Science.gov (United States)

    Tsai, Chia-Ching; Chang, Chih-Hsiang

    2007-01-01

    This study investigates the effect of advertising with physically attractive models on male and female adolescents. The findings suggest that highly attractive models are less effective than those who are normally attractive. Implications of social comparison are discussed.

  1. Protease activity in the larval stage of the parasitoid wasp, Eulophus pennicornis (Nees) (Hymenoptera: Eulophidae); effects of protease inhibitors.

    Science.gov (United States)

    Down, R E; Ford, L; Mosson, H J; Fitches, E; Gatehouse, J A; Gatehouse, A M

    1999-08-01

    Hymenopteran, parasitoid wasps have good potential for use in integrated pest management (IPM); for example, the gregarious ectoparasitoid, Eulophus pennicornis, has been suggested as a biological control agent for larvae of the tomato moth (Lacanobia oleracea L.). However, the processes by which such parasitic larvae are able to utilize the nutritional resource provided by the host have been little studied. Protease activity was present in E. pennicornis larvae, and characterization of the enzymes responsible for proteolysis was performed using a range of synthetic substrates and specific inhibitors. Serine protease enzymes was both trypsin- and chymotrypsin-like activities were present. A range of plant-derived serine protease inhibitors was tested for activity against these enzymes. Certain inhibitors, notably soybean Kunitz inhibitor (SKTI), inhibited enzyme activity by > 80% at pests are to form a component of IPM systems, possible adverse effects, whether direct or indirect, of transgene expression on parasitoids like E. pennicornis should be considered. PMID:10466123

  2. Effects of female diet and age on offspring sex ratio of the solitary parasitoid Pachycrepoideus vindemmiae (Rondani (Hymenoptera, Pteromalidae

    Directory of Open Access Journals (Sweden)

    Hao-Yuan Hu

    2012-06-01

    Full Text Available Effects of female diet and age on offspring sex ratio of the solitary parasitoid Pachycrepoideus vindemmiae (Rondani (Hymenoptera, Pteromalidae. Theories predict that females of parasitoid wasps would adjust the offspring sex ratio to environmental conditions in the oviposition patch, but the diet and age of females would also affect the sex ratio adjustment. Our focus was to test the effects of female diet and age on offspring sex ratio of the solitary parasitoid wasp, Pachycrepoideus vindemmiae (Rondani, 1875. Our results showed that females fed with honey had significantly less female biased offspring sex ratio than those fed only with water. Offspring sex ratio (male percentage decreased with female age or female longevity at the beginning of oviposition but increased at the end. There should be a sperm limitation in P. vindemmiae females at the end of oviposition, and a higher frequency of unfertilized eggs were laid then. Females also laid more unfertilized eggs at the beginning of oviposition, which would be necessary to insure the mating among offspring. Male offspring developed faster and emerged earlier, which would also reduce the risk of virginity in offspring with female-biased sex ratio.

  3. Mating Frequency and Effects on Sex Ratio in Female Parasitoids of xanthopimpla Stemmator (Thunberg). Implications in biological control Programmes

    International Nuclear Information System (INIS)

    Cereals, especially maize and sorghum are the most important field crops in Africa. classical biological Control is a management strategy that employs natural enemies against exotic pests on cereal crops. The method has been used against Chilo partellus (Swinhoe) (Lepidoptera: Crambidae), an introduced pest of maize, using the larval parasitoid cotesia flavipes (Cameron). However, C. flavipes is not able to attack all stem borer species in targeted areas. to complement its work, Xanthopimpla stemmator has successfully been established in Mauritius on Chilo sacchariphagus (Bojer). It is a common phenomenon for haplo-diploid parasitoids to give rise to male progeny when insemination does not take place. Mating becomes important to the parasitoid population since a male biased sex ratio can bring about collapse of the population. The aim of this study was to determine wether xanthopimpla stemmator females mat more than once and wether sex ratio of progeny is affected by multiple mating in female X. stemmator. The female showed a tendency to mate once. Multiple mating did not have any significant effect on either sex ratio or longevity. More males were produced in multiple mated females than once mated females.The effect of multiple mating in X. stemmator on sex ratio in relation to biocontrol programmes are discussed

  4. Side effects of some pesticides on the silverleaf whitefly’s parasitoid, Eretmocerus mundus Mercet (Hymenoptera: Aphelinidae under laboratory conditions

    Directory of Open Access Journals (Sweden)

    Mustafa PORTAKALDALI

    2015-12-01

    Full Text Available The silverleaf whitefly, Bemisia tabaci (Gennadius (Hemiptera: Aleyrodidae is one of major pests in greenhouses vegetable cultivation. Eretmocerus mundus Mercet (Hymenoptera: Aphelinidae has an important role among effective parasitoids used in biological control of the silverleaf whitefly. Nondestructive or less destructive pesticides against this parasitoid should be preferred in the scope of biological control. For this goal, side effects of 8 plant protection products, including spinosad, pyriproxyfen, abamectin, emamectin benzoate, copper oxychloride, kresoxim-methyl+boscalid, dimethoate and propineb+cymoxanil on pupae and adults of E. mundus were tested in this laboratory study conducted according to IOBC standards. As a result, pesticides containing spinosad, abamectin and dimethoate were determined as highly destructive to pupae and adults of E. mundus, and pesticide containing emamectin benzoate was found as moderately harmful. As for propineb+cymoxanil, pyriproxyfen, kresoxim-methyl+boscalid and copper oxychloride, they were determined as ineffective on the parasitoid under laboratory conditions. These results obtained from experiments that were conducted under laboratory conditions also have to be supported by field or semi-field experiment’s results.

  5. The Effects of Attractiveness and Status on Personality Evaluation

    Directory of Open Access Journals (Sweden)

    Stefano Tartaglia

    2015-11-01

    Full Text Available Research on personality has shown that perceiving a person as attractive fosters positive expectations about his/her personal characteristics. Literature has also demonstrated a significant link between personality traits and occupational achievement. Present research examines the combined effects of attractiveness, occupational status, and gender on the evaluation of others’ personality, according to the Big Five model. The study consisted of a 2 (Attractiveness: High vs. Low x 2 (occupational Status: High vs. Low x 2 (Target gender: Male vs. Female between-subjects experimental design (N = 476. Results showed that attractive targets were considered more positively than unattractive targets, and this effect was even stronger for male targets. Occupational status influenced perceived agreeableness (lower for high-status targets and perceived conscientiousness (higher for high-status targets.

  6. The Effects of Attractiveness and Status on Personality Evaluation.

    Science.gov (United States)

    Tartaglia, Stefano; Rollero, Chiara

    2015-11-01

    Research on personality has shown that perceiving a person as attractive fosters positive expectations about his/her personal characteristics. Literature has also demonstrated a significant link between personality traits and occupational achievement. Present research examines the combined effects of attractiveness, occupational status, and gender on the evaluation of others' personality, according to the Big Five model. The study consisted of a 2 (Attractiveness: High vs. Low) x 2 (occupational Status: High vs. Low) x 2 (Target gender: Male vs. Female) between-subjects experimental design (N = 476). Results showed that attractive targets were considered more positively than unattractive targets, and this effect was even stronger for male targets. Occupational status influenced perceived agreeableness (lower for high-status targets) and perceived conscientiousness (higher for high-status targets). PMID:27247685

  7. Inconsistent genetic structure among members of a multitrophic system: did bruchid parasitoids (Horismenus spp.) escape the effects of bean domestication?

    Science.gov (United States)

    Laurin-Lemay, S; Angers, B; Benrey, B; Brodeur, J

    2013-04-01

    Anthropogenic range expansion and cultural practices have modified the distribution, abundance and genetic diversity of domesticated organisms, thereby altering multitrophic assemblages through space and time. The putative Mesoamerican domestication centre of the common bean, Phaseolus vulgaris L., in Mexico allows investigating the effects of plant domestication on the genetic structure of members of a multitrophic system. The aim of this study was to compare the evolutionary history of Horismenus parasitoids (Hymenoptera: Eulophidae) to those of their bruchid beetle hosts (Coleoptera: Bruchidae) and their domesticated host plant (P. vulgaris), in the context of traditional agriculture in Mexico. We analyzed the population genetic structure of four Horismenus species in Mexico using mitochondrial COI haplotype data. The two most abundant parasitoid species were Horismenus depressus and Horismenus missouriensis. Horismenus missouriensis were infected by Wolbachia endosymbionts and had little to no population differentiation (F(ST) = 0.06). We suspect the mitochondrial history of H. missouriensis to be blurred by Wolbachia, because differentiation among infected vs. non-infected individuals exists (F(ST) = 0.11). Populations of H. depressus were found to be highly differentiated (F(ST) = 0.34), but the genetic structuring could not be explained by tested spatial components. We then compared the genetic structure observed in this parasitoid species to previously published studies on bruchid beetles and their host plants. Despite extensive human-mediated migration and likely population homogenization of its two Acanthoscelides bruchid beetle hosts, H. depressus populations are structured like its host plant, by a recent dispersal from a diverse ancestral gene pool. Distinct evolutionary dynamics may explain inconsistent patterns among trophic levels. Parasitoids likely migrate from wild bean populations and are poorly adapted to bean storage conditions similar to

  8. Local and landscape effects in a host-parasitoid interaction network along a forest-cropland gradient.

    Science.gov (United States)

    Osorio, Sergio; Arnan, Xavier; Bassols, Emili; Vicens, Narcís; Bosch, Jordi

    2015-10-01

    Land-use driven habitat modification is a major driver of biodiversity loss and impoverishment of interaction diversity. This may affect ecosystem services such as pollination and biological control. Our objective is to analyze the effects of local (nesting environment: farms vs. tree stands) and landscape (forest-cropland gradient) factors on the structure and composition of a cavity-nesting bee-wasp (CNBW) community, their nests associates (henceforth parasitoids), and their interactions. We set up 24 nest-trapping stations in a fragmented, extensively farmed area of ~100 km². We obtained 2035 nests containing 7572 brood cells representing 17 bee and 18 wasp species, attacked by 20 parasitoid species. Community structure and composition, as well as network structure, were much more dependent on local than on landscape factors. Host abundance and richness were higher in farms. In addition, host abundance was positively correlated to cropland cover. We also found highly significant differences between nesting environments in host community composition. Structure and composition of the parasitoid community were conditioned by the structure and composition of the host community. Network structure was affected by nesting environment but not by landscape factors. Interactions tended to be more diverse in farms. This result was mostly explained by differences in network size (greater in farms). However, generality was significantly higher in farms even after controlling for network size, indicating that differences in species' interaction patterns associated to differences in community composition between the two nesting environments are also affecting network structure. In conclusion, open habitats associated with extensively farmed exploitations favor local CNBW diversity (especially bees) and result in more complex host-parasitoid interaction networks in comparison to forested areas. The conservation value of this kind of open habitat is important in view of the

  9. A critical assessment of the effects of Bt transgenic plants on parasitoids.

    Science.gov (United States)

    Chen, Mao; Zhao, Jian-Zhou; Collins, Hilda L; Earle, Elizabeth D; Cao, Jun; Shelton, Anthony M

    2008-01-01

    The ecological safety of transgenic insecticidal plants expressing crystal proteins (Cry toxins) from the bacterium Bacillus thuringiensis (Bt) continues to be debated. Much of the debate has focused on nontarget organisms, especially predators and parasitoids that help control populations of pest insects in many crops. Although many studies have been conducted on predators, few reports have examined parasitoids but some of them have reported negative impacts. None of the previous reports were able to clearly characterize the cause of the negative impact. In order to provide a critical assessment, we used a novel paradigm consisting of a strain of the insect pest, Plutella xylostella (herbivore), resistant to Cry1C and allowed it to feed on Bt plants and then become parasitized by Diadegma insulare, an important endoparasitoid of P. xylostella. Our results indicated that the parasitoid was exposed to a biologically active form of the Cy1C protein while in the host but was not harmed by such exposure. Parallel studies conducted with several commonly used insecticides indicated they significantly reduced parasitism rates on strains of P. xylostella resistant to these insecticides. These results provide the first clear evidence of the lack of hazard to a parasitoid by a Bt plant, compared to traditional insecticides, and describe a test to rigorously evaluate the risks Bt plants pose to predators and parasitoids. PMID:18523682

  10. Fitness effects and transmission routes of a microsporidian parasite infecting Drosophila and its parasitoids.

    Science.gov (United States)

    Futerman, P H; Layen, S J; Kotzen, M L; Franzen, C; Kraaijeveld, A R; Godfray, H C J

    2006-04-01

    A microsporidian infection was discovered in laboratory cultures of Drosophila species. Ultrastructural examination suggested it belonged to the poorly characterized species Tubulinosema kingi, and morphological and sequence data are presented. We explored how T. kingi affected the fitness of Drosophila melanogaster and D. subobscura, as well as the fitness of 2 of their parasitoids, Asobara tabida and Pachycrepoideus vindemiae. In Drosophila, infections caused changes in most of the traits we looked at that were associated with fitness, in particular causing a 34-55% reduction in early-life fecundity. Parasitoid fitness was affected more severely by infection than that of their hosts, with pupal mortality in particular increasing by 75-89%. We investigated the most important routes of transmission for T. kingi in a laboratory setting. Letting Drosophila larvae feed on medium contaminated with spores from infected dead flies resulted in 100% infection. Low levels of transmission (<10%) were found between larvae, and vertically between mothers and their offspring. Parasitoids developing in infected hosts all became infected, but infected adults were neither able to transmit the pathogen to their offspring nor to their offspring's Drosophila host, either directly, or via contamination of the ovipositor or other body parts. A field survey of Drosophila and their parasitoids in southern England revealed no natural infections. We discuss the potential importance of Microsporidia in parasitoid-host interactions, and for those working with Drosophila in the laboratory. PMID:16318674

  11. Effects of plant protease inhibitors, oryzacystatin I and soybean Bowman-Birk inhibitor, on the aphid Macrosiphum euphorbiae (Homoptera, Aphididae) and its parasitoid Aphelinus abdominalis (Hymenoptera, Aphelinidae).

    Science.gov (United States)

    Azzouz, H; Cherqui, A; Campan, E D M; Rahbé, Y; Duport, G; Jouanin, L; Kaiser, L; Giordanengo, P

    2005-01-01

    Transgenic plants expressing protease inhibitors (PIs) have emerged in recent years as an alternative strategy for pest control. Beneficial insects such as parasitoids may therefore be exposed to these entomotoxins either via the host or by direct exposure to the plant itself. With the objective of assessing the effects of PIs towards aphid parasitoids, bioassays using soybean Bowman-Birk inhibitor (SbBBI) or oryzacystatin I (OCI) on artificial diet were performed on Macrosiphum euphorbiae-Aphelinus abdominalis system. OCI significantly reduced nymphal survival of the potato aphid M. euphorbiae and prevented aphids from reproducing. This negative effect was much more pronounced than with other aphid species. On the contrary, SbBBI did not affect nymphal viability but significantly altered adult demographic parameters. Enzymatic inhibition assays showed that digestive proteolytic activity of larvae and adults of Aphelinus abdominalis predominantly relies on serine proteases and especially on chymotrypsin-like activity. Immunoassays suggested that OCI bound to aphid proteins and accumulated in aphid tissues, whereas SbBBI remained unbound in the gut. Bioassays using M. euphorbiae reared on artificial diets supplemented with both OCI and SbBBI showed a fitness impairment of Aphelinus abdominalis that developed on intoxicated aphids. However, only SbBBI was detected in parasitoid larvae, while no PI could be detected in adult parasitoids that emerged from PI-intoxicated aphids. The potential impact of PI-expressing plants on aphid parasitoids and their combined efficiency for aphid control are discussed. PMID:15686649

  12. Effects of Certain Counselor Behaviors on Perceived Expertness and Attractiveness.

    Science.gov (United States)

    Barak, Azy; And Others

    1982-01-01

    Examined effects and relative contribution of three counselor behaviors (nonverbal behavior, jargon, and attire) on perceived expertise and attractiveness. Results revealed that all three independent variables significantly affected the two rated dimensions. Nonverbal behavior accounted for most of the variance and differentially affected ratings…

  13. BIOLOGICAL CONTROL OF OLIVE FLY: BALANCING PARASITOID EFFECTIVENESS AGAINST NON-TARGET IMPACTS

    Science.gov (United States)

    Olive fly, Bactrocera oleae (Diptera: Tephritidae), has become an important pest of California olives, and is the target of a classical biological control program. We report here on the pre-release screening of imported parasitoids Hymenoptera:Braconidae), conducted in the University of California ...

  14. Hyperparasitoids use herbivore-induced plant volatiles to locate their parasitoid host.

    Science.gov (United States)

    Poelman, Erik H; Bruinsma, Maaike; Zhu, Feng; Weldegergis, Berhane T; Boursault, Aline E; Jongema, Yde; van Loon, Joop J A; Vet, Louise E M; Harvey, Jeffrey A; Dicke, Marcel

    2012-01-01

    Plants respond to herbivory with the emission of induced plant volatiles. These volatiles may attract parasitic wasps (parasitoids) that attack the herbivores. Although in this sense the emission of volatiles has been hypothesized to be beneficial to the plant, it is still debated whether this is also the case under natural conditions because other organisms such as herbivores also respond to the emitted volatiles. One important group of organisms, the enemies of parasitoids, hyperparasitoids, has not been included in this debate because little is known about their foraging behaviour. Here, we address whether hyperparasitoids use herbivore-induced plant volatiles to locate their host. We show that hyperparasitoids find their victims through herbivore-induced plant volatiles emitted in response to attack by caterpillars that in turn had been parasitized by primary parasitoids. Moreover, only one of two species of parasitoids affected herbivore-induced plant volatiles resulting in the attraction of more hyperparasitoids than volatiles from plants damaged by healthy caterpillars. This resulted in higher levels of hyperparasitism of the parasitoid that indirectly gave away its presence through its effect on plant odours induced by its caterpillar host. Here, we provide evidence for a role of compounds in the oral secretion of parasitized caterpillars that induce these changes in plant volatile emission. Our results demonstrate that the effects of herbivore-induced plant volatiles should be placed in a community-wide perspective that includes species in the fourth trophic level to improve our understanding of the ecological functions of volatile release by plants. Furthermore, these findings suggest that the impact of species in the fourth trophic level should also be considered when developing Integrated Pest Management strategies aimed at optimizing the control of insect pests using parasitoids. PMID:23209379

  15. Biological control of Indianmeal moth (Lepidoptera: Pyralidae) on finished stored products using egg and larval parasitoids.

    Science.gov (United States)

    Grieshop, Matthew J; Flinn, Paul W; Nechols, James R

    2006-08-01

    Biological control using hymenopteran parasitoids presents an attractive alternative to insecticides for reducing infestations and damage from the Indianmeal moth, Plodia interpunctella (Hübner) (Lepidoptera: Pyralidae), in retail and warehouse environments. We examined the potential for using combinations of the egg parasitoid Trichogramma deion Riley (Hymenoptera: Trichogrammatidae), and the larval parasitoid Habrobracon hebetor (Say) (Hymenoptera: Braconidae) for preventing infestations of P. interpunctella in coarse-ground cornmeal as well as the influence of packaging on parasitoid effectiveness. Treatments included one or both parasitoids and either cornmeal infested with P. interpunctella eggs or eggs deposited on the surface of plastic bags containing cornmeal. H. hebetor had a significant impact on the number of live P. interpunctella, suppressing populations by approximately 71% in both unbagged and bagged cornmeal. In contrast, T. deion did not suppress P. interpunctella in unbagged cornmeal. However, when released on bagged cornmeal, T. deion significantly increased the level of pest suppression (87%) over bagging alone (15%). When H. hebetor was added to bagged cornmeal, there was a significant reduction of live P. interpunctella compared with the control (70.6%), with a further reduction observed when T. deion was added (96.7%). These findings suggest that, in most situations, a combined release of both T. deion and H. hebetor would have the greatest impact; because even though packaging may protect most of the stored products, there are usually areas in the storage landscape where poor sanitation is present. PMID:16937658

  16. Effects of Banana Plantation Pesticides on the Immune Response of Lepidopteran Larvae and Their Parasitoid Natural Enemies

    Directory of Open Access Journals (Sweden)

    Angela M. Smilanich

    2012-06-01

    Full Text Available Basic research on the insect immune response has progressed dramatically within the last two decades, showing that immunity is one of the most effective defenses against foreign invaders. As such, it is important to understand the causes of variation in this response. Here, we investigate the effects of pesticides used in Costa Rican banana plantations on the immune response of the lepidopteran larva, Caligo memnon (Brassolinae. In addition, we performed a parasitism survey of the banana plantations and surrounding forests to provide a broader assessment of pesticide effects on parasitoid populations. All caterpillars for the immune assay were collected from two banana plantations and brought to La Selva Biology Station for immune challenge. Individuals were fed leaves from the plantations (pesticide or leaves from La Selva (pesticide-free, then immune challenged with injected sephadex beads. We found that individuals feeding on pesticide leaves had significantly lower bead melanization compared to individuals feeding on pesticide-free leaves. Nonetheless, the parasitism survey showed that caterpillars from the banana plantations had lower parasitism rates compared to caterpillars from the La Selva forest. This study adds to the growing body of evidence documenting negative effects of pesticides on the insect immune response and on adult parasitoids, and underscores the need for more research at the intersection between ecological entomology and immunology.

  17. Expatriates' Ethnicity and their Effectiveness: "Similarity Attraction" or "Inverse Resonance"?

    OpenAIRE

    Stuart C. Carr; Ihfanyi Ehiobuche; Robert Rugimbana; Don Munro

    1996-01-01

    Studies of expatriate effectiveness have tended to restrict themselves to Westerners sojourning in non-Western countries or to non-Westerners studying in the West, thereby overlooking non-Western expatriates working in Third World countries. Reconstituting diverse principles from social comparison and identity theories, attribution research, the similarity-attraction literature, psychotherapy, psychody namics, and experimental social psychology, we predict that the relationship between (a) pe...

  18. Effects of endophyte colonization of Vicia faba (Fabaceae) plants on the life-history of leafminer parasitoids Phaedrotoma scabriventris (hymenoptera: braconidae) and Diglyphus isaea (hymenoptera: eulophidae).

    Science.gov (United States)

    Akutse, Komivi S; Fiaboe, Komi K M; Van den Berg, Johnnie; Ekesi, Sunday; Maniania, Nguya K

    2014-01-01

    Effects of the fungal endophytes Beauveria bassiana (isolates ICIPE 279, G1LU3, S4SU1) and Hypocrea lixii (isolate F3ST1) on the life-history of Phaedrotoma scabriventris and Diglyphus isaea, parasitoids of the pea leafminer Liriomyza huidobrensis, were studied in the laboratory. Parasitoids were allowed to parasitize 2(nd) and 3(rd) instar L. huidobrensis larvae reared on endophytically-inoculated faba bean, Vicia faba. In the control, parasitoids were reared on non-inoculated host plants. Parasitism, pupation, adult emergence and survival were recorded. No significant difference was observed between the control and the endophyte-inoculated plants in terms of parasitism rates of P. scabriventris (p = 0.68) and D. isaea (p = 0.45) and adult' survival times (p = 0.06). The survival period of the F1 progeny of P. scabriventris was reduced (p<0.0001) in B. bassiana S4SU1 to 28 days as compared to more than 40 days for B. bassiana G1LU3, ICIPE 279 and H. lixii F3ST1. However, no significant difference (p = 0.54) was observed in the survival times of the F1 progeny of D. isaea. This study has demonstrated that together, endophytes and parasitoids have beneficial effects in L. huidobrensis population suppression. PMID:25338084

  19. Effects of Endophyte Colonization of Vicia faba (Fabaceae) Plants on the Life–History of Leafminer Parasitoids Phaedrotoma scabriventris (Hymenoptera: Braconidae) and Diglyphus isaea (Hymenoptera: Eulophidae)

    Science.gov (United States)

    Akutse, Komivi S.; Fiaboe, Komi K. M.; Van den Berg, Johnnie; Ekesi, Sunday; Maniania, Nguya K.

    2014-01-01

    Effects of the fungal endophytes Beauveria bassiana (isolates ICIPE 279, G1LU3, S4SU1) and Hypocrea lixii (isolate F3ST1) on the life-history of Phaedrotoma scabriventris and Diglyphus isaea, parasitoids of the pea leafminer Liriomyza huidobrensis, were studied in the laboratory. Parasitoids were allowed to parasitize 2nd and 3rd instar L. huidobrensis larvae reared on endophytically-inoculated faba bean, Vicia faba. In the control, parasitoids were reared on non-inoculated host plants. Parasitism, pupation, adult emergence and survival were recorded. No significant difference was observed between the control and the endophyte-inoculated plants in terms of parasitism rates of P. scabriventris (p = 0.68) and D. isaea (p = 0.45) and adult' survival times (p = 0.06). The survival period of the F1 progeny of P. scabriventris was reduced (p<0.0001) in B. bassiana S4SU1 to 28 days as compared to more than 40 days for B. bassiana G1LU3, ICIPE 279 and H. lixii F3ST1. However, no significant difference (p = 0.54) was observed in the survival times of the F1 progeny of D. isaea. This study has demonstrated that together, endophytes and parasitoids have beneficial effects in L. huidobrensis population suppression. PMID:25338084

  20. Effects of endophyte colonization of Vicia faba (Fabaceae plants on the life-history of leafminer parasitoids Phaedrotoma scabriventris (hymenoptera: braconidae and Diglyphus isaea (hymenoptera: eulophidae.

    Directory of Open Access Journals (Sweden)

    Komivi S Akutse

    Full Text Available Effects of the fungal endophytes Beauveria bassiana (isolates ICIPE 279, G1LU3, S4SU1 and Hypocrea lixii (isolate F3ST1 on the life-history of Phaedrotoma scabriventris and Diglyphus isaea, parasitoids of the pea leafminer Liriomyza huidobrensis, were studied in the laboratory. Parasitoids were allowed to parasitize 2(nd and 3(rd instar L. huidobrensis larvae reared on endophytically-inoculated faba bean, Vicia faba. In the control, parasitoids were reared on non-inoculated host plants. Parasitism, pupation, adult emergence and survival were recorded. No significant difference was observed between the control and the endophyte-inoculated plants in terms of parasitism rates of P. scabriventris (p = 0.68 and D. isaea (p = 0.45 and adult' survival times (p = 0.06. The survival period of the F1 progeny of P. scabriventris was reduced (p<0.0001 in B. bassiana S4SU1 to 28 days as compared to more than 40 days for B. bassiana G1LU3, ICIPE 279 and H. lixii F3ST1. However, no significant difference (p = 0.54 was observed in the survival times of the F1 progeny of D. isaea. This study has demonstrated that together, endophytes and parasitoids have beneficial effects in L. huidobrensis population suppression.

  1. Cascading effects of early-season herbivory on late-season herbivores and their parasitoids.

    Science.gov (United States)

    Hernandez-Cumplido, Johnattran; Glauser, Gaetan; Benrey, Betty

    2016-05-01

    There is an increasing awareness that herbivory by one insect species induces changes in a plant that affect the performance of other herbivore species that feed on the same plant. However, previous studies of interspecies interactions mediated by plant defense responses have rarely taken into account different insect guilds or the third trophic level. Using a combination of field and laboratory experiments, we examined how early-season herbivory in lima bean plants (Phaseolus lunatus) by the leaf-chewing herbivore Cerotoma ruficornis and the bean pod weevil Apion godmani affects the abundance and performance of the seed beetle Zabrotes subfasciatus and that of its parasitoid Stenocorse bruchivora, which occurs on the plants at the end of the growing season. In addition, we determined the consequences of early-season herbivore-induced defenses on plant performance. We hypothesized that early-season induction would affect plant reproduction and, hence, would alter the suitability of seeds for late-season seed-eating beetles, and that this would in turn alter the vulnerability of these seed beetles to parasitoids. We found strong support for these hypotheses. In the field, early-season herbivory negatively affected plant reproduction and seeds of these plants suffered lower levels of infestation by seed-eating beetles, which in turn suffered less parasitism. Laboratory assays with field-collected seeds confirmed that the performance of beetles and parasitoids was lower on seeds from plants that had been subjected to early-season herbivory. Further analyses revealed that seeds produced by control plants were larger, heavier, and had a higher concentration of cyanogenic glycosides and total protein content than seeds from plants subjected to herbivory. Our results provide insight into how direct and indirect interactions between and within different trophic levels affect the dynamics and structure of complex communities. PMID:27349104

  2. Quantum Effects of Uniform Bose Atomic Gases with Weak Attraction

    Institute of Scientific and Technical Information of China (English)

    CHENG Ze

    2011-01-01

    @@ We find that uniform Bose atomic gases with weak attraction can undergo a Bardeen-Cooper-Schrieffer(BCS)condensation below a critical temperature.In the BCS condensation state,bare atoms with opposite wave vectors are bound into pairs,and unpaired bare atoms are transformed into a new kind of quasi-particles,i.e.the dressed atoms.The atom-pair system is a condensate or a superfluid and the dressed-atom system is a normal fluid.The critical temperature and the effective mass of dressed atoms are derived analytically.The transition from the BCS condensation state to the normal state is a first-order phase transition.%We find that uniform Bose atomic gases with weak attraction can undergo a Bardeen-Cooper-Schrieffer (BCS)condensation below a critical temperature. In the BCS condensation state, bare atoms with opposite wave vectors are bound into pairs, and unpaired bare atoms are transformed into a new kind of quasi-particles, i.e. the dressed atoms. The atom-pair system is a condensate or a superfluid and the dressed-atom system is a normal fluid. The critical temperature and the effective mass of dressed atoms are derived analytically. The transition from the BCS condensation state to the normal state is a first-order phase transition.

  3. Liquid drops attract or repel by the inverted Cheerios effect.

    Science.gov (United States)

    Karpitschka, Stefan; Pandey, Anupam; Lubbers, Luuk A; Weijs, Joost H; Botto, Lorenzo; Das, Siddhartha; Andreotti, Bruno; Snoeijer, Jacco H

    2016-07-01

    Solid particles floating at a liquid interface exhibit a long-ranged attraction mediated by surface tension. In the absence of bulk elasticity, this is the dominant lateral interaction of mechanical origin. Here, we show that an analogous long-range interaction occurs between adjacent droplets on solid substrates, which crucially relies on a combination of capillarity and bulk elasticity. We experimentally observe the interaction between droplets on soft gels and provide a theoretical framework that quantitatively predicts the interaction force between the droplets. Remarkably, we find that, although on thick substrates the interaction is purely attractive and leads to drop-drop coalescence, for relatively thin substrates a short-range repulsion occurs, which prevents the two drops from coming into direct contact. This versatile interaction is the liquid-on-solid analog of the "Cheerios effect." The effect will strongly influence the condensation and coarsening of drops on soft polymer films, and has potential implications for colloidal assembly and mechanobiology. PMID:27298348

  4. Do biopesticides affect the demographic traits of a parasitoid wasp and its biocontrol services through sublethal effects?

    Science.gov (United States)

    Biondi, Antonio; Zappalà, Lucia; Stark, John D; Desneux, Nicolas

    2013-01-01

    Pesticide risk assessments are usually based on short-term acute toxicity tests, while longer-term population dynamic related traits, critical to the success of biological control and Integrated Pest Management (IPM) programs, are often overlooked. This is increasingly important with respect to new biopesticides that frequently cause no short-term acute effects, but that can induce multiple physiological and behavioral sublethal effects, leading to a decrease in population growth and ecosystem services. In this study we assessed the lethal and sublethal effects of six biopesticides [abamectin, azadirachtin, Bacillus thuringiensis, borax plus citrus oil (Prev-Am®), emamectin benzoate, and spinosad], used in tomato crops to control the invasive pest Tuta absoluta (Lepidoptera: Gelechiidae), on adults and pupae of the parasitoid Bracon nigricans (Hymenoptera: Braconidae). Data on female survival and production of female offspring were used to calculate population growth indexes as a measure of population recovery after pesticide exposure. Spinosad caused 100% and 80% mortality in exposed adults (even 10 d after the treatment) and pupae, respectively. Although most of the biopesticides had low levels of acute toxicity, multiple sublethal effects were observed. The biocontrol activity of both females that survived 1-h and 10-d old residues, and females that emerged from topically treated pupae was significantly affected by the application of the neurotoxic insecticides emamectin benzoate and abamectin. Furthermore, very low B. nigricans demographic growth indices were estimated for these two insecticides, indicating potential local extinction of the wasp populations. Among the tested products, Bt proved to be the safest for B. nigricans adults and pupae. Our findings emphasize that acute toxicity assessment alone cannot fully predict the actual impact of pesticides on non-target parasitoids. Thus, sublethal effects related to the species specific life-history variables

  5. Effects of pesticide applications on the euonymus scale (Homoptera: Diaspididae) and its parasitoid, Encarsia citrina (Hymenoptera: Aphelinidae).

    Science.gov (United States)

    Rebek, Eric J; Sadof, Clifford S

    2003-04-01

    Novel biorational insecticides are rapidly replacing more toxic, broad-spectrum compounds to control pests of ornamental plants. These new formulations are widely regarded as safe, effective, and environmentally sound with minimal impact on nontarget organisms. We tested several biorational and traditional insecticides for their ability to control euonymus scale, Unaspis euonymi (Comstock), and their potential impacts on the aphelinid parasitoid, Encarsia citrina (Crawford). Soil-applied acephate and foliar-applied pyriproxyfen exhibited superior control of euonymus scale, but also reduced numbers of surviving E. citrina. Imidacloprid failed to control euonymus scale and decreased parasitism by E. citrina. Thus, the potential impact of a pesticide on biological control is not necessarily predicted by its potential longevity, mode of delivery, or its toxicity to the target pest. Finding the best fit of a compound into an integrated pest management program requires a consideration of all these factors and direct study of effects on the natural enemies of pests. PMID:14994813

  6. Combined effect of gamma radiation and the parasitoid T.evanescens, against potato tuber moth P. operculella (Lepidoptera- Gelechiidae)

    International Nuclear Information System (INIS)

    The present study was conducted to evaluate the effect of gamma irradiation on certain biological aspects of the potato tuber moth, Phthorimaea operculella. as a result of pupal irradiation, fecundity and fertility were significantly decreased as dose levels increased. In addition, a dose level at 400 Gy completely inhibited full pupal development, whether they were combined with non-irradiated or irradiated individuals of opposite sexes. A significant negative relationship between dose levels and percentage of egg hatching was obtained; [ the higher the dose, the lower the percentage of egg hatching]. The percentage of egg hatching resulting from irradiated male pupae was higher than that resulting from irradiated female pupae. Females were more sensitive than males which is evident from the lower LD value. Laboratory experiments were carried out to investigate the effect of the parasitoid Trichogramma evanescens on the resulting irradiated full-grown pupae of Phthorimaea operculella at different photoperiods and temperatures.

  7. Effect of doses and of refuge on the insecticide selectivity to predators and parasitoids of soybean insect pests

    International Nuclear Information System (INIS)

    A field experiment was conducted to evaluate seasonal effect of insecticides on predators and parasitoids of soybean insect pests. A randomized block design was used, with three replications, and the experiment was set up in the experimental station of the EMBRAPA-Centro Nacional de Pesquisa de Soja, located at Londrina, PR, Brazil. Treatments consisted of insecticide application to control the velvet bean caterpillar (1/21/1993) or the stink bug complex (3/4/1993). Insect population was sampled through the shock technique, consisting of an application of a broad spectrum insecticide over the plants to be sampled, being the insects collected on cloths placed on the ground, and transferred to the laboratory to be identified and counted. Statistical analysis revealed no differences on the populations of species of predators, diptera or himenoptera as a group. No effects of pest resurgence or secondary pest outbreaks were also observed. (author)

  8. Study of two conditioning methods of parasitoids used in biological control prior to inundative releases in apple orchards

    Directory of Open Access Journals (Sweden)

    Valérie-Anne Dumont

    2011-12-01

    Full Text Available The rosy apple aphid, Dysaphis plantaginea Pass., is a major pest in apple orchards in Belgium. Two micro-hymenopteran parasitoids Aphidius matricariae Haliday and Ephedrus cerasicola Stary are potentially capable of controlling this pest. However, when released in orchards the adult parasitoids tend to disperse. Based on the results of previous work it is proposed that the reason is that the artificial diet in which they are raised does not contain the odors that enable the parasitoids to identify the habitat where there are suitable aphid hosts. To optimize the control and make it economically effective it is important to reduce dispersal. This might be done by conditioning parasitoids during rearing by exposing them to the odors associated with orchards. The odor used in this study was a hydrodistillate of apple leaves, the main host-plant of the targeted aphid. Two methods of conditioning were used: 1 soaking mummies of the parasitoid in p ure hydrodistillate, 2 including a defined concentration of hydrodistillate in the artificial diet used for rearing the parasitoid. They were exposed to either a dilution of 100×, 200× and 1000× in two consecutive generations. The response of adult parasitoids to odors was determined using a dual choice olfactometer. Of the E. cerasicola conditioned by soaking the mummies 70–75% of individuals were attracted to the odor of plants infested with D. plantaginea compared to the 55–60% in the controls. The A.matricariae that were conditioned by feeding them artificial diets containing different concentrations of apple odor for one or two generations, showed no preference for the odor of apple leaves. Second generation adults of E. cerasicola exposed to a 200 times dilution of pure hydrodistillate showed a more marked response to apple odor.

  9. Cross-channel effects of vocal and physical attractiveness and their implications for interpersonal perception.

    Science.gov (United States)

    Zuckerman, M; Miyake, K; Hodgins, H S

    1991-04-01

    Judges' ratings of senders' vocal attractiveness from face-plus-voice (F+V) cues were influenced by senders' physical attractiveness, and ratings of senders' physical attractiveness from F+V cues were influenced by senders' vocal attractiveness. This occurred even when judges were warned not to pay attention to face when rating vocal attractiveness and not to pay attention to voice when rating physical attractiveness. Instructions to judge attractiveness without being told which channel to attend to resulted in ratings influenced by both vocal and physical attractiveness of senders. Because of cross-channel effects, F+V attractiveness ratings should be more highly related to F+V personality impressions than attractiveness ratings based on only face or only voice. The results supported this hypothesis. Implications of cross-channel effects for research on the attractiveness stereotype were discussed. PMID:2037966

  10. Effects of Children's Physical Attractiveness on Teachers' Evaluations

    Science.gov (United States)

    Rich, Jordan

    1975-01-01

    After viewing a photograph of an attractive or unattractive child and a vignette of possible misbehavior by that child, female teachers evaluated each student for blame, punishment and personality. Attractive children received better personality ratings than did unattractive. Unattractive girls were given more lenient punishments than unattractive…

  11. Effects of Physical Attractiveness on Evaluation of Vocal Performance.

    Science.gov (United States)

    Wapnick, Joel; Darrow, Alice Ann; Kovacs, Jolan; Dalrymple, Lucinda

    1997-01-01

    Studies whether physical attractiveness of singers affects judges' ratings of their vocal performances. Reveals that physical attractiveness does impact evaluation, that male raters were more severe than female raters, and that the rating of undergraduate majors versus graduate students and professors combined were not differently affected by…

  12. Adaptation effects to attractiveness of face photographs and art portraits are domain-specific

    OpenAIRE

    Hayn-Leichsenring, Gregor U.; Kloth, Nadine; Schweinberger, Stefan R.; Redies, Christoph

    2013-01-01

    We studied the neural coding of facial attractiveness by investigating effects of adaptation to attractive and unattractive human faces on the perceived attractiveness of veridical human face pictures (Experiment 1) and art portraits (Experiment 2). Experiment 1 revealed a clear pattern of contrastive aftereffects. Relative to a pre-adaptation baseline, the perceived attractiveness of faces was increased after adaptation to unattractive faces, and was decreased after adaptation to attractive ...

  13. Variation in a Host–Parasitoid Interaction across Independent Populations

    Directory of Open Access Journals (Sweden)

    Saskya van Nouhuys

    2012-12-01

    Full Text Available Antagonistic relationships between parasitoids and their insect hosts involve multiple traits and are shaped by their ecological and evolutionary context. The parasitoid wasp Cotesia melitaearum and its host butterfly Melitaea cinxia occur in several locations around the Baltic sea, with differences in landscape structure, population sizes and the histories of the populations. We compared the virulence of the parasitoid and the susceptibility of the host from five populations in a reciprocal transplant-style experiment using the progeny of five independent host and parasitoid individuals from each population. The host populations showed significant differences in the rate of encapsulation and parasitoid development rate. The parasitoid populations differed in brood size, development rate, pupal size and adult longevity. Some trait differences depended on specific host-parasitoid combinations, but neither species performed systematically better or worse in experiments involving local versus non-local populations of the other species. Furthermore, individuals from host populations with the most recent common ancestry did not perform alike, and there was no negative effect due to a history of inbreeding in the parasitoid. The complex pattern of variation in the traits related to the vulnerability of the host and the ability of the parasitoid to exploit the host may reflect multiple functions of the traits that would hinder simple local adaptation.

  14. Variation in a Host–Parasitoid Interaction across Independent Populations

    Science.gov (United States)

    van Nouhuys, Saskya; Niemikapee, Suvi; Hanski, Ilkka

    2012-01-01

    Antagonistic relationships between parasitoids and their insect hosts involve multiple traits and are shaped by their ecological and evolutionary context. The parasitoid wasp Cotesia melitaearum and its host butterfly Melitaea cinxia occur in several locations around the Baltic sea, with differences in landscape structure, population sizes and the histories of the populations. We compared the virulence of the parasitoid and the susceptibility of the host from five populations in a reciprocal transplant-style experiment using the progeny of five independent host and parasitoid individuals from each population. The host populations showed significant differences in the rate of encapsulation and parasitoid development rate. The parasitoid populations differed in brood size, development rate, pupal size and adult longevity. Some trait differences depended on specific host-parasitoid combinations, but neither species performed systematically better or worse in experiments involving local versus non-local populations of the other species. Furthermore, individuals from host populations with the most recent common ancestry did not perform alike, and there was no negative effect due to a history of inbreeding in the parasitoid. The complex pattern of variation in the traits related to the vulnerability of the host and the ability of the parasitoid to exploit the host may reflect multiple functions of the traits that would hinder simple local adaptation. PMID:26466737

  15. Variation in a Host-Parasitoid Interaction across Independent Populations.

    Science.gov (United States)

    van Nouhuys, Saskya; Niemikapee, Suvi; Hanski, Ilkka

    2012-01-01

    Antagonistic relationships between parasitoids and their insect hosts involve multiple traits and are shaped by their ecological and evolutionary context. The parasitoid wasp Cotesia melitaearum and its host butterfly Melitaea cinxia occur in several locations around the Baltic sea, with differences in landscape structure, population sizes and the histories of the populations. We compared the virulence of the parasitoid and the susceptibility of the host from five populations in a reciprocal transplant-style experiment using the progeny of five independent host and parasitoid individuals from each population. The host populations showed significant differences in the rate of encapsulation and parasitoid development rate. The parasitoid populations differed in brood size, development rate, pupal size and adult longevity. Some trait differences depended on specific host-parasitoid combinations, but neither species performed systematically better or worse in experiments involving local versus non-local populations of the other species. Furthermore, individuals from host populations with the most recent common ancestry did not perform alike, and there was no negative effect due to a history of inbreeding in the parasitoid. The complex pattern of variation in the traits related to the vulnerability of the host and the ability of the parasitoid to exploit the host may reflect multiple functions of the traits that would hinder simple local adaptation. PMID:26466737

  16. Effect of continuous rearing on courtship acoustics of five braconid parasitoids, candidates for augmentative biological control of Anastrepha species

    Science.gov (United States)

    The courtship acoustics of five species of parasitoid wasps (Hymenoptera: Braconidae), potential candidates for augmentative biological control of Anastrepha species (Diptera: Tephritidae), were compared between recently colonized individuals and those continuously reared 70-148 generations. During...

  17. Effect of doses and of refuge on the insecticide selectivity to predators and parasitoids of soybean insect pests; Efeito de doses e de refugio sobre a seletividade de inseticidas a predadores e parasitoides de pragas de soja

    Energy Technology Data Exchange (ETDEWEB)

    Corso, Ivan Carlos; Gazzoni, Decio Luiz; Nery, Manoel Eugenio [EMBRAPA, Londrina, PR (Brazil). Centro Nacional de Pesquisa de Soja]. E-mail: gazzoni@cnpso.embrapa.br

    1999-09-15

    A field experiment was conducted to evaluate seasonal effect of insecticides on predators and parasitoids of soybean insect pests. A randomized block design was used, with three replications, and the experiment was set up in the experimental station of the EMBRAPA-Centro Nacional de Pesquisa de Soja, located at Londrina, PR, Brazil. Treatments consisted of insecticide application to control the velvet bean caterpillar (1/21/1993) or the stink bug complex (3/4/1993). Insect population was sampled through the shock technique, consisting of an application of a broad spectrum insecticide over the plants to be sampled, being the insects collected on cloths placed on the ground, and transferred to the laboratory to be identified and counted. Statistical analysis revealed no differences on the populations of species of predators, diptera or himenoptera as a group. No effects of pest resurgence or secondary pest outbreaks were also observed. (author)

  18. Side effects of different pesticides used in citrus on the adult stage of the parasitoid Aphytis melinus DeBach (Hymenoptera Aphelinidae and its progeny

    Directory of Open Access Journals (Sweden)

    J. E. Gonzalez-Zamora

    2013-05-01

    Full Text Available Twelve pesticides commonly used in citrus in Spain were tested on adults of Aphytis melinus DeBach to determine their effects on parasitoid survival and fecundity, and the duration of the residue of each pesticide. Six of these pesticides were found to be harmless to moderately harmful to this parasitoid in a laboratory assay in closed Petri dishes: spinosad (bait formulation, azadirachtin, fenbutatin, fosetyl-Al, copper oxichloride, and mancozeb, with their scores on the reduction of beneficial capacity (RBC index being between 21.4 and 94.6% after one week. The other six pesticides classified as harmful were tested on citrus plants to study their persistence over time under greenhouse conditions: Pirimicarb, pyriproxifen, paraffinic oil, abamectin, chlorpyrifos, and lambda-cyhalothrin. Most of these products reduced their negative effect on adults of A. melinus between one and six weeks after treatment, although lambda-cyhalothrin was still harmful to parasitoids 11 weeks after application. This information can help growers and consultants to make decisions about pesticide selection and application timing in citrus in order to support IPM implementation when A. melinus is present.

  19. Differential effects of jasmonic acid treatment of Brassica nigra on the attraction of pollinators, parasitoids, and butterflies

    OpenAIRE

    Bruinsma, M.; IJdema, H.; Loon, van, J.Th.; Dicke, M.

    2008-01-01

    Herbivore-induced plant defences influence the behaviour of herbivores as well as that of their natural enemies. Jasmonic acid is one of the key hormones involved in both these direct and indirect induced defences. Jasmonic acid treatment of plants changes the composition of defence chemicals in the plants, induces volatile emission, and increases the production of extrafloral nectar. However, few studies have addressed the potential influence of induced defences on flower nectar chemistry an...

  20. Motivational orientations and task autonomy fit: effects on organizational attraction.

    Science.gov (United States)

    Wu, Yu-Chi

    2012-02-01

    The main purpose of this study was to investigate whether there is congruence between applicant needs (i.e., motivational orientations) and what is available (i.e., task autonomy) from an organizational perspective based on the fit between needs and supply. The fit between work motivation and task autonomy was examined to see whether it was associated with organizational attraction. This experimental study included two phases. Phase 1 participants consisted of 446 undergraduate students, of whom 228 were recruited to participate in Phase 2. The fit relations between task autonomy and intrinsic motivation and between task control and extrinsic motivation were characterized. Findings indicated that the fit between work motivation and task autonomy was positively associated with organizational attraction. Based on these results, it may be inferred that employers should emphasize job characteristics such as autonomy or control orientations to attract individuals, and focus on the most suitable work motivations for their organizations. PMID:22582692

  1. Biological control of cultural heritage pest Coleoptera and Lepidoptera with the help of parasitoid Hymenoptera

    Directory of Open Access Journals (Sweden)

    Matthias Schöller

    2011-08-01

    Full Text Available Natural enemies are known from many cultural heritage pests, but their potential for biological control has been marginally exploited only. In this publication, examples of practical and commercial application of parasitoids of beetles and moths are compiled as well as laboratory research that contributes to the development of guidelines for parasitoid releases. One the one hand there are parasitoids found to occur simultaneously with the pests in buildings, on the other hand there are parasitoids that were never found to be associated with the respective pests but accept them if brought into the cultural heritage environments. An example for the latter is the egg parasitoid Trichogramma evanescens euproctidis, a parasitoid of moth eggs including those of the cloth moth Tineola bisselliella. In semi-field trials it was shown that inundative releases of the egg parasitoids are necessary and that effectiveness is reduced on thick cloth with long strand. Trichogramma release units have to be placed directly on the cloth to be protected. A naturally occuring parasitoid of Anobiid beetles is the pteromalid larval parasitoid Lariophagus distinguendus. This parasitoid was applied against the drugstore beetle Stegobium paniceum in historic libraries and against spider beetles (Ptininae in historic buildings. A simulation model for the population-dynamics of L. distinguendus and the golden spider beetle Niptus hololeucus is presented. Finally, monitoring of the Braconid larval parasitoid Spathius exarator used for indirect monitoring of the common furniture beetle Anobium punctatum is described. The future potential of parasitoids to control cultural heritage pests is discussed.

  2. The effect of larval and early adult experience on behavioural plasticity of the aphid parasitoid Aphidius ervi (Hymenoptera, Braconidae, Aphidiinae)

    Science.gov (United States)

    Villagra, Cristian A.; Pennacchio, Francesco; Niemeyer, Hermann M.

    2007-11-01

    The relevance of the integration of preimaginal and eclosion experiences on the subsequent habitat preferences and mate finding by the adult has been rarely tested in holometabolous insects. In this work, the effect of larval and early adult experiences on the behavioural responses of adult males of the aphid parasitoid, Aphidius ervi, towards volatiles from the host-plant complex (HPC) and from conspecific females were evaluated. Two experience factors were considered: host diet (normal diet=ND; artificial diet=AD), and eclosion, i.e. extraction or non-extraction of the parasitoid larva from the parasitised aphid (extracted=EX; non-extracted=NE). Thus, four treatments were set up: ND/NE, ND/EX, AD/NE and AD/EX. Glass Y-tube olfactometers were used to investigate the responses of adult A. ervi males to the odour sources used. Males from the ND/NE treatment showed a shorter latency to the first choice of olfactometer arms, displayed a marked preference towards the HPC olfactometer arm, and spent more time in the HPC arm than males from the other treatments. Only the interaction of host diet and eclosion experiences proved to be relevant in explaining the differences in latency to first choice, time spent in olfactometers arms, and behaviours displayed in the olfactometer arms. These results show the importance of the integration of larval and eclosion experiences in the development of stereotyped responses of the adults. This process may involve memory retention from the preimaginal and emergence period, but further research is needed to disentangle the contribution of each stage. The response to conspecific females was much less affected by the treatments in relation to first arm choice and times in olfactometer arms, suggesting a pheromone-mediated behaviour, even though a prompter and more intense wing fanning courtship behaviour was registered in the ND/NE males compared to males from the AD/NE treatment. These results show that sexual behaviours are less

  3. Effect of similarity of ego identity status on interpersonal attraction.

    Science.gov (United States)

    Goldman, J A; Rosenzweig, C M; Lutter, A D

    1980-04-01

    Similarity of ego identity status, assessed by Marcia's four-category classification system, was related to interpersonal attraction. Using male and female college students as subjects, this study found that (1) while all judges preferred targets who had or who are undergoing a crisis to those who have not had a crisis, (2) diffuse judges preferred targets with no commitments to those with commitments, and (3) judges with commitments preferred a foreclosure target more than judges without commitments. Differential evaluations of the targets' intelligence, knowledge of current events, adjustment, and morality were also found. Results are discussed both in terms of previous research positively relating personality similarity to attraction and Erikson's theory of the relationship between ego identity development and intimacy in interpersonal relations. PMID:24318017

  4. The effects of facial adiposity on attractiveness and perceived leadership ability.

    Science.gov (United States)

    Re, Daniel E; Perrett, David I

    2014-01-01

    Facial attractiveness has a positive influence on electoral success both in experimental paradigms and in the real world. One parameter that influences facial attractiveness and social judgements is facial adiposity (a facial correlate to body mass index, BMI). Overweight people have high facial adiposity and are perceived to be less attractive and lower in leadership ability. Here, we used an interactive design in order to assess whether the most attractive level of facial adiposity is also perceived as most leader-like. We found that participants reduced facial adiposity more to maximize attractiveness than to maximize perceived leadership ability. These results indicate that facial appearance impacts leadership judgements beyond the effects of attractiveness. We suggest that the disparity between optimal facial adiposity in attractiveness and leadership judgements stems from social trends that have produced thin ideals for attractiveness, while leadership judgements are associated with perception of physical dominance. PMID:23971489

  5. Facial cosmetics have little effect on attractiveness judgments compared with identity.

    Science.gov (United States)

    Jones, Alex L; Kramer, S S

    2015-01-01

    The vast majority of women in modern societies use facial cosmetics, which modify facial cues to attractiveness. However, the size of this increase remains unclear--how much more attractive are individuals after an application of cosmetics? Here, we utilised a 'new statistics' approach, calculating the effect size of cosmetics on attractiveness using a within-subjects design, and compared this with the effect size due to identity--that is, the inherent differences in attractiveness between people. Women were photographed with and without cosmetics, and these images were rated for attractiveness by a second group of participants. The proportion of variance in attractiveness explained by identity was much greater than the variance within models due to cosmetics. This result was unchanged after statistically controlling for the perceived amount of cosmetics that each model used. Although cosmetics increase attractiveness, the effect is small, and the benefits of cosmetics may be inflated in everyday thinking. PMID:26489218

  6. Molecular theory for the effects of solute attractive forces on hydrophobic interactions

    CERN Document Server

    Chaudhari, M I; Asthagiri, D; Tan, L; Pratt, L R

    2015-01-01

    We consider the local molecular field (LMF) theory for the effects of solute attractive forces on hydrophobic interactions. The principal result of LMF theory is outlined, then tested by obtaining radial distribution functions (rdfs) for Ar atoms in water, with and without attractive interactions distinguished by the Weeks-Chandler-Andersen (WCA) separation. Change from purely repulsive atomic solute interactions to include realistic attractive interactions substantially \\emph{diminishes} the strength of hydrophobic bonds. Since attractions make a big contribution to hydrophobic interactions, Pratt-Chandler theory, which did not include attractions, should not be simply comparable to computer simulation results with general physical interactions, including attractions. The rdfs permit evaluation of osmotic second virial coefficients $B_2$. Those $B_2$ are consistent with the conclusion that incorporation of attractive interactions leads to more positive (repulsive) values. In all cases here, $B_2$ becomes mor...

  7. Plant surface wax affects parasitoid's response to host footprints

    Science.gov (United States)

    Rostás, Michael; Ruf, Daniel; Zabka, Vanessa; Hildebrandt, Ulrich

    2008-10-01

    The plant surface is the substrate upon which herbivorous insects and natural enemies meet and thus represents the stage for interactions between the three trophic levels. Plant surfaces are covered by an epicuticular wax layer which is highly variable depending on species, cultivar or plant part. Differences in wax chemistry may modulate ecological interactions. We explored whether caterpillars of Spodoptera frugiperda, when walking over a plant surface, leave a chemical trail (kairomones) that can be detected by the parasitoid Cotesia marginiventris. Chemistry and micromorphology of cuticular waxes of two barley eceriferum wax mutants ( cer-za.126, cer-yp.949) and wild-type cv. Bonus (wt) were assessed. The plants were then used to investigate potential surface effects on the detectability of caterpillar kairomones. Here we provide evidence that C. marginiventris responds to chemical footprints of its host. Parasitoids were able to detect the kairomone on wild-type plants and on both cer mutants but the response to cer-yp.949 (reduced wax, high aldehyde fraction) was less pronounced. Experiments with caterpillar-treated wt and mutant leaves offered simultaneously, confirmed this observation: no difference in wasp response was found when wt was tested against cer-za.126 (reduced wax, wt-like chemical composition) but wt was significantly more attractive than cer-yp.949. This demonstrates for the first time that the wax layer can modulate the detectability of host kairomones.

  8. Physical attractiveness biases in ratings of employment suitability: tracking down the "beauty is beastly" effect.

    Science.gov (United States)

    Johnson, Stefanie K; Podratz, Kenneth E; Dipboye, Robert L; Gibbons, Ellie

    2010-01-01

    The "what is beautiful is good" heuristic suggests that physically attractive persons benefit from their attractiveness in a large range of situations, including perceptions of employment suitability. Conversely, the "beauty is beastly" effect suggests that attractiveness can be detrimental to women in certain employment contexts, although these findings have been less consistent than those for the "what is beautiful is good" effect. The current research seeks to uncover situations in which beauty might be detrimental for female applicants. In two studies, we found that attractiveness can be detrimental for women applying for masculine sex-typed jobs for which physical appearance is perceived as unimportant. PMID:20575336

  9. Effect of mating on sex attraction in Bactericera cockerelli with evidence of refractoriness

    Science.gov (United States)

    We investigated the effect of mating on female attractiveness and male responsiveness in the potato psyllid, Bactericera (= Paratrioza) cockerelli (Šulc) (Hemiptera: Triozidae), a major pest of potato. Mating induced a behavioral refractoriness during which males are not attracted to females. This ...

  10. The Effects of Physical Attractiveness on Attributions of Causality for Success and Failure.

    Science.gov (United States)

    Wiener, Seymour; And Others

    Based on research indicating the existence of a generalized positive stereotype of physically attractive individuals, the present study was designed to investigate the effects of an individual's attractiveness on attributions about his achievement-related behavior. In the context of an accuracy-of-person perception task, 162 male and female…

  11. Effects of Attractiveness and Gender on the Perception of Achievement-Related Variables.

    Science.gov (United States)

    Chia, R. C.; Allred, L. J.; Grossnickle, W. F.; Lee, G. W.

    1998-01-01

    Examines the effects of physical attractiveness and gender on perceptions of academic success, achievement-related traits, intelligence, initiative, and attributions of ability and effort in relation to academic success. Finds that being perceived as physically attractive created positive impressions of achievement-related traits for men but…

  12. Physical Attractiveness: Interactive Effects of Counselor and Client on Counseling Processes.

    Science.gov (United States)

    Vargas, Alice M.; Borkowski, John G.

    1983-01-01

    Assessed how the physical attractiveness of counselors and clients interacted to build rapport in two experiments involving college students (N=128 and N=64). Results showed the counselor's physical attractiveness had a major impact on her perceived effectiveness and the client's expectation of success irrespective of the client's attractiveness…

  13. Parasitoids of Queensland Fruit Fly Bactrocera tryoni in Australia and Prospects for Improved Biological Control

    Directory of Open Access Journals (Sweden)

    Olivia L. Reynolds

    2012-10-01

    Full Text Available This review draws together available information on the biology, methods for study, and culturing of hymenopteran parasitoids of the Queensland fruit fly, Bactrocera tryoni, and assesses prospects for improving biological control of this serious pest. Augmentative release of the native and naturalised Australian parasitoids, especially the braconid Diachasmimorpha tryoni, may result in better management of B. tryoni in some parts of Australia. Mass releases are an especially attractive option for areas of inland eastern Australia around the Fruit Fly Exclusion Zone that produces B. tryoni-free fruits for export. Diachasmimorpha tryoni has been successful in other locations such as Hawaii for the biological control of other fruit fly species. Biological control could contribute to local eradication of isolated outbreaks and more general suppression and/or eradication of the B. tryoni population in endemic areas. Combining biological control with the use of sterile insect technique offers scope for synergy because the former is most effective at high pest densities and the latter most economical when the pest becomes scarce. Recommendations are made on methods for culturing and study of four B. tryoni parasitoids present in Australia along with research priorities for optimising augmentative biological control of B. tryoni.

  14. The Effect of Professor's Attractiveness on Distance Learning Students

    Science.gov (United States)

    Liu, Jeanny; Tomasi, Stella D.

    2015-01-01

    Technology enabled learning is becoming more popular and pervasive in education. While the effectiveness of distance learning versus traditional classroom education is strongly debated, human factors such as students' perception of their professors can influence their desire to learn. This research examines the perceptual effect of attractive…

  15. Effective Factors on Sports Tourism: Emphasizing Development in Sports Natural Attractions

    Directory of Open Access Journals (Sweden)

    Hasan Safdel

    2014-12-01

    Full Text Available The goal of this research is the evaluation of some of the effective environmental attractions on Khorasan Razavi’s sports tourism development. The research statistical population include of all in charge expert and professors in field of sport and tourism as 120 persons. This research is past-event descriptive that had been performed based on field method. Sampling had been performed as Categorized to determine effective environmental attraction effects on Khorasan Razavi’s tourism development, the questions had been analyzed by researcher that its validity had been confirmed by experts and Cronbach's alpha had been calculated as 0.82. Findings show that from experts and managers viewpoints, effective factors on sport tourism development with emphasis on sport natural attractions include of tourism and pilgrim attractions, natural treatment and warm water attractions and summer and water sports that are the most important items in Khorasan Razavi. Also there are three important factors in relation to problem and obstacles as Management problems, cultural problems and infrastructure problems. Research results show that pilgrim locations are effective to attract tourism and knowing the effect of tourism industry development effects and present obstacles and limitation in the province, attention to sport tourism development importance and applying various benefits of sport tourist attraction are necessary and programming and sport tourism developments by province planner and policy makers would be required.

  16. Testing the strength and robustness of the attraction effect in consumer decision making

    OpenAIRE

    Crosetto, Paolo; Gaudeul, Alexia

    2014-01-01

    We report the results of an original experiment that was designed to test the strength and robustness of the attraction effect. Rather than the usual simple tests for this effect, we consider a conceptually simple consumer purchasing task where alternatives are however difficult to evaluate. For the attraction effect to be observed, the consumer must go through two steps: the first is to find out that two or more options are comparable, which leads him to exclude the dominated alternatives. T...

  17. Effective Marketing Strategies to Attract Business Visitors at Trade Shows

    OpenAIRE

    Mei-Chin Chu; Sui-Ming Chiu

    2013-01-01

    Trade shows have been the focus of recent research as constituting one of the most effective marketing strategies.Related issues have been discussed extensively in the literature. How to achieve better performance is central tothese discussions. Studies on the key factors that influence trade show performance have focused mainly onsubjective opinions from the perspective of the staff at exhibitions. In this study, we explored the key criteria fora business visitor in selecting suppliers at a ...

  18. Multiple ant species tending lac insect Kerria yunnanensis (Hemiptera: Kerriidae) provide asymmetric protection against parasitoids.

    Science.gov (United States)

    Chen, Youqing; Lu, Zhixing; Li, Qiao; Hoffmann, Benjamin D; Zhang, Wei

    2014-01-01

    This study investigated the effects of ant attendance on the parasitoid community and parasitism of lac insect Kerria yunnanensis aggregations in Yunnan province, China. We manipulated ant attendance to establish three treatments: (1) ant exclusion; (2) low ant attendance by several ant species; and (3) high ant attendance by Crematogaster macaoensis. Five parasitoid species were collected, with two species contributing 82.7 and 13.2% of total abundance respectively. Total parasitoid abundance was lowest in the February sample when K. yunnanensis was in its younger life stage, being significantly lower in the ant exclusion treatment. In April, all three treatments had significantly different parasitoid abundances, being highest in the ant exclusion treatment and the lowest in the high ant attendance treatment. When ants were present, there were strong negative relationships between total parasitoid abundance and ant abundance, with the relationships being dependent upon the ant species composition and abundance. The patterns of total parasitoid abundance were driven by the two most abundant parasitoid species. Parasitoid species richness did not differ among treatments or between sample times, however, multivariate analysis confirmed that overall parasitoid community structure differed significantly among treatments and between sample times, with the high ant attendance treatment differing most from the other two treatments. Interestingly the absence of ants did not result in increased parasitism from four of the five parasitoids. Ants in lac insect farming systems have a clear role for agricultural pest management. A full understanding of the asymmetric abilities of ants to influence parasitoid communities, and affect parasitism of hosts will require further experimental manipulation to assess the relative roles of 1) the abundance of each individual ant species on parasitoid access to hosts, 2) competition among parasitoids, and 3) the interaction between the

  19. Promotion of cooperation induced by nonlinear attractive effect in spatial Prisoner's Dilemma game

    CERN Document Server

    Guan, J Y; Huang, Z G; Xu, X J; Wang, Y H; Guan, Jian-Yue; Wu, Zhi-Xi; Huang, Zi-Gang; Xu, Xin-Jian; Wang, Ying-Hai

    2006-01-01

    We introduce nonlinear attractive effects into a spatial Prisoner's Dilemma game where the players located on a square lattice can either cooperate with their nearest neighbors or defect. In every generation, each player updates its strategy by firstly choosing one of the neighbors with a probability proportional to $\\mathcal{A}^\\alpha$ denoting the attractiveness of the neighbor, where $\\mathcal{A}$ is the payoff collected by it and $\\alpha$ ($\\geq$0) is a free parameter characterizing the extent of the nonlinear effect; and then adopting its strategy with a probability dependent on their payoff difference. Using Monte Carlo simulations, we investigate the density $\\rho_C$ of cooperators in the stationary state for different values of $\\alpha$. It is shown that the introduction of such attractive effect remarkably promotes the emergence and persistence of cooperation over a wide range of the temptation to defect. In particular, for large values of $\\alpha$, i.e., strong nonlinear attractive effects, the syst...

  20. The Effects of Sex of Subject, Sex and Attractiveness of Photo on Facial Recognition.

    Science.gov (United States)

    Carroo, Agatha W.; Mozingo, R.

    1989-01-01

    Assessed effect of sex of subject, and sex and attractiveness of photo on facial recognition with 25 male and 25 female college students. Found male subjects performed better with male faces with d' prime scores. (Author/ABL)

  1. Intergroup Cooperation and Intergroup Attraction: The Effect of Previous Interaction and Outcome of Combined Effort

    Science.gov (United States)

    Worchel, Stephen; And Others

    1977-01-01

    Tests the hypothesis that the effect of intergroup cooperation on intergroup attraction would depend on both the outcome of the cooperation and the nature of the past interaction between groups. (Author/RK)

  2. Inhibition of the larval ecdysis and emergence behavior of the parasitoid Cotesia congregata by methoprene.

    Science.gov (United States)

    Beckage, Nancy E.; Foreman, Regina C.; Palmatier, Crystal M.; Tan, Frances F.

    2002-07-01

    Parasitism of the tobacco hornworm, Manduca sexta, by the braconid wasp Cotesia congregata, induces developmental arrest of the host in the larval stage. During the final instar of the host, its juvenile hormone (JH) titer is elevated, preventing host metamorphosis. This study investigated the effects of hormonal manipulation of the host on the parasitoid's emergence behavior. The second larval ecdysis of the wasps coincides with their emergence from the host, and application of the juvenile hormone analogue methoprene to day 4 fifth instar hosts either delayed or totally suppressed the subsequent emergence of the wasps. Effects of methoprene were dose-dependent and no parasitoids emerged following treatment of host larvae with doses >50 &mgr;g. Parasitoids which failed to emerge eventually succumbed as unecydsed pharate third instar larvae in the hemocoel of the host. Effects of host methoprene treatment on parasitoid metamorphosis were also assessed, and metamorphic disruption occurred at much lower dosages compared with doses necessary to suppress parasitoid emergence behavior. The inhibitory effect of methoprene on parasitoid emergence behavior appears to be mediated by effects of this hormone on the synthesis or release of ecdysis-triggering hormone (ETH) in the parasitoid, the proximate endocrine cue which triggers ecdysis behavior in free-living insects. ETH accumulated in the epitracheal Inka cells of parasitoids developing in methoprene-treated hosts, suggestive of a lack of hormone release. Thus, the hormonal modulation of parasitoid emergence behavior appears to be complex, involving a suite of hormones including JH, ecdysteroid, and peptide hormones. PMID:12770067

  3. Cold storage possibilities of a larval parasitoid, Venturia canescens (Gravenhorst) (Hymenoptera: Ichneumonidae)

    OpenAIRE

    TUNCA, Hilal; NazanYEŞİL, Ayşe; ÇALIŞKAN, Türkan Feyza

    2014-01-01

    The effects of cold storage on the biology of the larval parasitoid Venturia canescens were tested. Storage studies were conducted in two stages, pre-adult and adult stage of the larval parasitoid, Venturia canescens (Gravenhorst) (Hymenoptera: Ichneumonidae). Pre-adult stage of parasitoid was stored in last larval stage of the hosts, Ephestia kuehniella Zeller (Lepidoptera: Pyralidae) and Plodia interpunctella Hübner (Lepidoptera: Pyralidae) at 5, 10, 15°C for 1, 3, 5, 7, and 15 days. Simila...

  4. [Contrast effects of background stimulus person on attitude similarity judgement and interpersonal attraction: a study of topic familiarity effect].

    Science.gov (United States)

    Tajima, T

    2000-10-01

    The purpose of this study was to examine the effects of a background stimulus person on attitude similarity judgement and interpersonal attraction. Mascaro and Graves (1973) argued that a contrast effect on perception of similarity mediated interpersonal attraction. In the present experiment, it was hypothesized that topic familiarity moderated the effects of a background stimulus person on attitude similarity judgement and interpersonal attraction. One hundred twenty-two (122) female students were randomly assigned to four groups, formed by two levels of topic familiarity and two levels of similarity for the background stimulus person. They saw the attitudes of two stimulus persons together, and were asked to rate perceived similarity and interpersonal attraction. Results showed that in familiar topic condition, contrast effect was not found for attitude similarity judgement, but it was found for interpersonal attraction. The finding suggested that presence of a background stimulus person immediately led to the contrast effect on interpersonal attraction. PMID:11140256

  5. Modeling distributions of flying insects: Effective attraction radius of pheromone in two and three dimensions. Journal of Theoretical Biology

    Science.gov (United States)

    The effective attraction radius (EAR) of an attractive pheromone-baited trap was defined as the radius of a passive “sticky” sphere that would intercept the same number of flying insects as the attractant. The EAR for a particular attractant and insect species in nature is easily determined by a cat...

  6. Structure and dynamics of Lithocolletis ringoniella-Parasitoids food web in apple orchards of Shaanxi, China

    Directory of Open Access Journals (Sweden)

    Xin Li

    2014-09-01

    Full Text Available The formation and evolution of food web is a self-organizing process. A food web, L. ringoniella-Parasitoids food web, was proposed in present study. With the apple pest Lithocolletis ringoniella as the basic host, four parasitoids, Apanteles theivorae, Sympiesis sericeicornis, Ageniaspis testaceipes, and Sympiesis Foerst are included in the food web. In this food web, A. theivorae and A. testaceipes are primary parasitoids of L. ringoniella. A. theivorae mainly parasitizes apodous larva of L. ringoniella while A. testaceipes only chooses L. ringoniella egg to parasitize (egg-larva endoparasitization. S. Foerst and S. sericeicornis are facultative hyper-parasitoids. They can parasitize not only the larvae and pupae of L. ringoniella, but also A. theivorae. S. sericeicornis can be hyper-parasitized by S. Foerst. The occurrence mechanism and population dynamics of L. ringoniella and parasitoids, and parasitization effect of parasitoids in apple orchards of Shaanxi, China, were described in detail.

  7. Effective super Tonks-Girardeau gases as ground states of strongly attractive multi-component fermions

    OpenAIRE

    Yin, Xiangguo; Guan, Xi-Wen; Batchelor, M. T.; Chen, Shu

    2010-01-01

    In the strong interaction limit, attractive fermions with $N$-component hyperfine states in a one-dimensional waveguide form unbreakable bound cluster states. We demonstrate that the ground state of strongly attractive SU($N$) Fermi gases can be effectively described by a super Tonks-Girardeau gas-like state composed of bosonic cluster states with strongly attractive cluster-cluster interaction for even $N$, and a Fermi duality of a super Tonks-Girardeau gas-like state composed of fermionic c...

  8. Interpersonal attraction as a joint function of primacy and recency effects.

    Science.gov (United States)

    Bell, P A

    1975-01-01

    Empirical primacy-recency inconsistencies between Byrne's reinforcement affect model of attraction and Anderson's information integration model of personality impression formation were explored. Thirty-six male and female Ss gave attraction responses to sequences of blocks of similar and dissimilar attitudes arranged in increasing or decreasing proportions of similarity and increasing or decreasing levels of topic importance. Results generally supported the hypothesis that attraction is a joint function of the proportion of similar attitudes within each block (recency) and cumulative proportion of similar attitudes before each response (primacy). This joint occurrence of primacy and recency effects was interpreted in terms of an affect neutralization hypothesis. PMID:24203836

  9. Effects on microhymenopteran progeny of different host exposure periods (Chrysomya megacephala, Calliphoridae to the parasitoid wasp Nasonia vitripennis (Hymenoptera: Pteromalidae

    Directory of Open Access Journals (Sweden)

    Renata da Silva Mello

    2010-02-01

    Full Text Available To test the assumption that exposure of the host to parasitoid for long periods could provoke superparasitism, the aim of this work was to test the consequences on the immature development time, productivity of parasitoids per pupa, sex ratio and rate of parasitism of Nasonia vitripennis bred in Chrysomya megacephala pupae. Each individual pupa was placed in a glass tube with one parasitoid female for 24, 48, 72 and 96 h period of exposure, under controlled laboratory conditions. Twenty replicates of each period were performed. ANOVA with a 5% significance level was applied. The 72 h exposure caused the immature development time to increase. The mean parasitoids emergence per pupa did not vary significantly with the time of exposure. There were a significantly higher number of females than males and a trend in sex ratio deviation towards the females in all of the treatments. An increase in the number of unviable pupae rates were observed with increased exposure time.Para testar a hipótese que longos períodos de exposição do hospedeiro ao parasitóide podem ocasionar o superparasitismo, o presente estudo teve como objetivo testar as conseqüências sobre o tempo de desenvolvimento do imaturo, a produtividade de parasitóides, razão sexual e taxa de parasitismo de Nasonia vitripennis criadas em pupas de Chrysomya megacephala. Cada pupa foi individualizada e alocada em um tudo de ensaio com uma fêmea de N. vitripennis por 24, 48, 72 ou 96 h, sob condições laboratoriais controladas. Foram realizadas 20 réplicas para cada período de exposição. ANOVA com significância de 5 % foi aplicada. A exposição de 72 h causou um aumento no tempo desenvolvimento. A média de emergência de parasitóides não variou significativamente entre os tempos de exposição. Houve um número significativamente maior de fêmeas e uma tendência ao desvio da razão sexual para fêmeas em todos os tratamentos. Foi verificado um aumento no número de pupas invi

  10. Effects of GNA transgenic sugarcane on life history parameters of Parallorhogas pyralophagus (Marsh) (Hymenoptera: Braconidae), a parasitoid of Mexican rice borer.

    Science.gov (United States)

    Tomov, Beverly Wachtel; Bernal, Julio S

    2003-06-01

    Parallorhogas pyralophagus (Marsh) is the principal parasitoid of the Mexican rice borer [Eoreuma loftini (Dyar)], the primary pest of sugarcane in south Texas. Insect resistant transgenic sugarcane producing Galanthus nivalis agglutinin (GNA) was developed to improve control of E. loftini. The present laboratory study addressed whether over two consecutive generations transgenic sugarcane delivered via artificial diet has adverse host-mediated effects on P. pyralophagus life history parameters. The results of this study showed that a number of life history parameters were affected by transgenic sugarcane, whereas others were not affected, and that effects varied between generations. In the first generation, adult longevity was increased by approximately 2 d, and cocoon to adult and egg to adult developmental times were prolonged by approximately 1 d in parasitoids exposed to transgenic sugarcane, whereas effects were not evident on adult size; egg load; egg to cocoon developmental time; rates of gain of longevity and egg load with adult size; and egg, larval, and pupal mortality. However, in the second generation, adult longevity was reduced by approximately 3 d, adult size by approximately 5%, egg load by approximately 24%, and rate of gain of longevity with adult size by approximately 21%, whereas effects were not evident on the rate of gain of egg load with adult size. It was concluded that although GNA transgenic sugarcane, ingested via E. loftini tissues, was not acutely toxic to P. pyralophagus, the sublethal effects on life history parameters measured in this study must be considered in a broader context to determine their possible ecological significance. PMID:12852590

  11. Hymenopteran parasitoids of diamondback moth (Lepidoptera: Ypeunomutidae) in northern Thailand.

    Science.gov (United States)

    Rowell, Brent; Bunsong, Nittayaporn; Satthaporn, Kosin; Phithamma, Sompian; Doungsa-Ard, Charnnarong

    2005-04-01

    Larvae of the diamondback moth, Plutella xylostella (L.) (Lepidoptera: Ypeunomutidae), cause severe economic damage to cabbage, Brassica oleracea L. variety capitata (Brassicaceae) and related vegetables in Thailand. Overuse of broad-spectrum insecticides for diamondback moth control is a serious problem and has obscured the contributions of indigenous parasitoids. Our objectives were to identify indigenous diamondback moth parasitoids in northern Thailand and to assess their potential for natural control. Six parasitoid species were reared from diamondback moth larvae and pupae collected in 1990 and in 2003-2004. These included the larval parasitoid Cotesia plutellae Kurdjumov (Braconidae), a larval-pupal parasitoid Macromalon orientale Kerrich (Ichneumonidae), and pupal parasitoids Diadromus collaris Gravenhorst (Ichneumonidae) and Brachymeria excarinata Gahan (Chalcididae). Single specimens of Isotima sp. Forster (Ichneumonidae) and Brachymeria lasus Walker (Chalcididae) also were reared from diamondback moth hosts. C. plutellae was the dominant larval parasitoid and was often reared from host larvae collected from fields sprayed regularly with insecticides; parasitism ranged from 14 to 78%. Average parasitism by M. orientale was only 0.5-6%. Parasitism of host pupae by D. collaris ranged from 9 to 31%, whereas B. excarinata pupal parasitism ranged from 9 to 25%. An integrated pest management (IPM) protocol using simple presence-absence sampling for lepidopterous larvae and the exclusive use of Bacillus thuringiensis (Bt) or neem resulted in the highest yields of undamaged cabbage compared with a control or weekly sprays of cypermethrin (local farmer practice). IPM programs focused on conservation of local diamondback moth parasitoids and on greater implementation of biological control will help alleviate growing public concerns regarding the effects of pesticides on vegetable growers and consumers. PMID:15889737

  12. Effects of water-channel attractions on single-file water permeation through nanochannels

    Science.gov (United States)

    Xu, Yousheng; Tian, Xingling; Lv, Mei; Deng, Maolin; He, Bing; Xiu, Peng; Tu, Yusong; Zheng, Youqu

    2016-07-01

    Single-file transportation of water across narrow nanochannels such as carbon nanotubes has attracted much attention in recent years. Such permeation can be greatly affected by the water-channel interactions; despite some progress, this issue has not been fully explored. Herein we use molecular dynamics simulations to investigate the effects of water-channel attractions on occupancy, translational (transportation) and orientational dynamics of water inside narrow single-walled carbon nanotubes (SWNTs). We use SWNTs as the model nanochannels and change the strength of water-nanotube attractions to mimic the changes in the hydrophobicity/polarity of the nanochannel. We investigate the dependence of water occupancy inside SWNTs on the water-channel attraction and identify the corresponding threshold values for drying states, wetting-drying transition states, and stably wetting states. As the strength of water-channel attractions increases, water flow increases rapidly first, and then decreases gradually; the maximal flow occurs in the case where the nanochannel is predominately filled with the 1D water wire but with a small fraction of ‘empty states’, indicating that appropriate empty-filling (drying-wetting) switching can promote water permeation. This maximal flow is unexpected, since in traditional view, the stable and tight hydrogen-bonding network of the water wire is the prerequisite for high permeability of water. The underlying mechanism is discussed from an energetic perspective. In addition, the effect of water-channel attractions on reorientational dynamics of the water wire is studied, and a negative correlation between the flipping frequency of water wire and the water-channel attraction is observed. The underlying mechanism is interpreted in term of the axial total dipole moment of inner water molecules. This work would help to better understand the effects of water-channel attractions on wetting properties of narrow nanochannels, and on single

  13. Packing of Fruit Fly Parasitoids for Augmentative Releases

    Directory of Open Access Journals (Sweden)

    Pablo Montoya

    2012-09-01

    Full Text Available The successful application of Augmentative Biological Control (ABC to control pest fruit flies (Diptera: Tephritidae confronts two fundamental requirements: (1 the establishment of efficient mass rearing procedures for the species to be released, and (2 the development of methodologies for the packing and release of parasitoids that permit a uniform distribution and their optimal field performance under an area-wide approach. Parasitoid distributions have been performed by ground and by air with moderate results; both options face challenges that remain to be addressed. Different devices and strategies have been used for these purposes, including paper bags and the chilled adult technique, both of which are commonly used when releasing sterile flies. However, insect parasitoids have morphological and behavioral characteristics that render the application of such methodologies suboptimal. In this paper, we discuss an alternate strategy for the augmentative release of parasitoids and describe packing conditions that favor the rearing and emergence of adult parasitoids for increased field performance. We conclude that the use of ABC, including the packaging of parasitoids, requires ongoing development to ensure that this technology remains a viable and effective control technique for pest fruit flies.

  14. Relationship between Physical Attractiveness, Physical Effectiveness, and Self-Esteem: A Cross-Sectional Analysis among Adolescents.

    Science.gov (United States)

    Thornton, Bill; Ryckman, Richard M.

    1991-01-01

    Examined contributions of physical attractiveness and physical effectiveness to self-esteem among adolescents in grades 7, 9, and 11, and college freshmen. Both attractiveness and effectiveness were significantly related to self-esteem of males and females. Attractiveness and effectiveness did not appear to be differentially important to…

  15. Reduced-risk pest management programs for eastern U.S. peach orchards: effects on arthropod predators, parasitoids, and select pests.

    Science.gov (United States)

    Biddinger, David J; Leslie, Timothy W; Joshi, Neelendra K

    2014-06-01

    We developed new integrated pest management programs for eastern U.S. peaches with minimal use of organophosphates. From 2002-2005, we assessed the ecological impacts of these reduced-risk programs versus grower standard conventional programs that still relied primarily on the use of organophosphorous and carbamate insecticides. Using a split-plot design replicated at four commercial Pennsylvania peach orchards, we quantified pesticide rates, environmental impact, and arthropod community response. We used Environmental Impact Quotient (EIQ) analysis based on the growers' pesticide records from each orchard to calculate seasonal cumulative EIQ field ratings for all years. Ecological effects of the reduced-risk and conventional program were also measured as the abundance and diversity of nontarget arthropod predators, parasitoids, and selected pest taxa. Pesticide inputs and EIQ values were substantially lower in reduced-risk programs compared with conventional spray programs. Arthropod arrays differed significantly between pest management programs: most beneficial predator and parasitoid taxa were positively associated with the reduced-risk program and negatively associated with the standard grower program. Regardless of the pest management program, we observed significant differences in species arrays in the peach tree canopy compared with the ground cover of the orchards, but the arthropod community did not differ among the field sites or based on distance from the edge of the orchard. We conclude that reduced-risk programs not only provide control comparable with that of conventional programs, but they also reduce negative environmental effects while conserving key arthropod biological control agents within eastern U.S. peach orchards. PMID:25026668

  16. Describing a multitrophic plant-herbivore-parasitoid system at four spatial scales

    Science.gov (United States)

    Cuautle, M.; Parra-Tabla, V.

    2014-02-01

    Herbivore-parasitoid interactions must be studied using a multitrophic and multispecies approach. The strength and direction of multiple effects through trophic levels may change across spatial scales. In this work, we use the herbaceous plant Ruellia nudiflora, its moth herbivore Tripudia quadrifera, and several parasitoid morphospecies that feed on the herbivore to answer the following questions: Do herbivore and parasitoid attack levels vary depending on the spatial scale considered? With which plant characteristics are the parasitoid and the herbivore associated? Do parasitoid morphospecies vary in the magnitude of their positive indirect effect on plant reproduction? We evaluated three approximations of herbivore and parasitoid abundance (raw numbers, ratios, and attack rates) at four spatial scales: regional (three different regions which differ in terms of abiotic and biotic characteristics); population (i.e. four populations within each region); patch (four 1 m2 plots in each population); and plant level (using a number of plant characteristics). Finally, we determined whether parasitoids have a positive indirect effect on plant reproductive success (seed number). Herbivore and parasitoid numbers differed at three of the spatial scales considered. However, herbivore/fruit ratio and attack rates did not differ at the population level. Parasitoid/host ratio and attack rates did not differ at any scale, although there was a tendency of a higher attack in one region. At the plant level, herbivore and parasitoid abundances were related to different plant traits, varying the importance and the direction (positive or negative) of those traits. In addition, only one parasitoid species (Bracon sp.) had a positive effect on plant fitness saving up to 20% of the seeds in a fruit. These results underline the importance of knowing the scales that are relevant to organisms at different trophic levels and distinguish between the specific effects of species.

  17. Brain potentials indicate the effect of other observers' emotions on perceptions of facial attractiveness.

    Science.gov (United States)

    Huang, Yujing; Pan, Xuwei; Mo, Yan; Ma, Qingguo

    2016-03-23

    Perceptions of facial attractiveness are sensitive to emotional expression of the perceived face. However, little is known about whether the emotional expression on the face of another observer of the perceived face may have an effect on perceptions of facial attractiveness. The present study used event-related potential technique to examine social influence of the emotional expression on the face of another observer of the perceived face on perceptions of facial attractiveness. The experiment consisted of two phases. In the first phase, a neutral target face was paired with two images of individuals gazing at the target face with smiling, fearful or neutral expressions. In the second phase, participants were asked to judge the attractiveness of the target face. We found that a target face was more attractive when other observers positively gazing at the target face in contrast to the condition when other observers were negative. Additionally, the results of brain potentials showed that the visual positive component P3 with peak latency from 270 to 330 ms was larger after participants observed the target face paired with smiling individuals than the target face paired with neutral individuals. These findings suggested that facial attractiveness of an individual may be influenced by the emotional expression on the face of another observer of the perceived face. PMID:26601630

  18. Particle attraction effects on the centrifugal casting and extrusion of alumina

    International Nuclear Information System (INIS)

    Interparticle attraction forces were empirically related to the centrifugal casting and extrusion behavior of flocculated alumina suspensions. Attractive forces were altered by two approaches: Salt flocculation, which entails regulating the electrical double-layer thickness through electrolyte additions; and screening of van der Waals attraction by steric interactions of surface-adsorbed fatty acids. Specimens produced by both compressibility at a critical maximum density that increased with decreasing interparticle attraction. Gradients in packing density during centrifugal casting were alleviated using both methods as long as spatial variations of the effective stress were within the low-compressibility range. We hypothesized that the reduced interparticle attraction in both methods may also raise the threshold packing density at which ductile-to-brittle transitions occur during plastic shear. Specimens prepared with oleic acid adlayers were highly plastic and easily extrudable at solids contents of up to 59 vol%, although salt-flocculated samples at 55 vol% density extruded at creeping flow rates that were insensitive to the applied pressure. Results suggested that particle rearrangement during shear, is a rate-limiting process, with an average relaxation time that is lowered by reducing interparticle attraction

  19. The Effects of Attitude Similarity, Spatial Relationship, and Task Difficulty on Interpersonal Attraction.

    Science.gov (United States)

    Krivonos, Paul D.

    1980-01-01

    Presents a study of the effects of the occupation of an individual's personal space on that individual's judgment of the invader when the invader's attitudes are known to the invadee. Also studies the effect of the difficulty of the task on the relationship between spatial orientation and interpersonal attraction. (JMF)

  20. Plants attract parasitic wasps to defend themselves against insect pests by releasing hexenol.

    Directory of Open Access Journals (Sweden)

    Jianing Wei

    Full Text Available BACKGROUND: Plant volatiles play an important role in defending plants against insect attacks by attracting their natural enemies. For example, green leaf volatiles (GLVs and terpenoids emitted from herbivore-damaged plants were found to be important in the host location of parasitic wasps. However, evidence of the functional roles and mechanisms of these semio-chemicals from a system of multiple plants in prey location by the parasitoid is limited. Little is known about the potential evolutionary trends between herbivore-induced host plant volatiles and the host location of their parasitoids. METHODOLOGY/PRINCIPAL FINDINGS: The present study includes hierarchical cluster analyses of plant volatile profiles from seven families of host and non-host plants of pea leafminer, Liriomyza huidobrensis, and behavioral responses of a naive parasitic wasp, Opius dissitus, to some principal volatile compounds. Here we show that plants can effectively pull wasps, O. dissitus, towards them by releasing a universally induced compound, (Z-3-hexenol, and potentially keep these plants safe from parasitic assaults by leafminer pests, L. huidobrensis. Specifically, we found that volatile profiles from healthy plants revealed a partly phylogenetic signal, while the inducible compounds of the infested-plants did not result from the fact that the induced plant volatiles dominate most of the volatile blends of the host and non-host plants of the leafminer pests. We further show that the parasitoids are capable of distinguishing the damaged host plant from the non-host plant of the leafminers. CONCLUSIONS/SIGNIFICANCE: Our results suggest that, as the most passive scenario of plant involvement, leafminers and mechanical damages evoke similar semio-chemicals. Using ubiquitous compounds, such as hexenol, for host location by general parasitoids could be an adaptation of the most conservative evolution of tritrophic interaction. Although for this, other compounds may be

  1. Molecular theory and the effects of solute attractive forces on hydrophobic interactions

    International Nuclear Information System (INIS)

    The role of solute attractive forces on hydrophobic interactions is studied by coordinated development of theory and simulation results for Ar atoms in water. We present a concise derivation of the local molecular field (LMF) theory for the effects of solute attractive forces on hydrophobic interactions, a derivation that clarifies the close relation of LMF theory to the EXP approximation applied to this problem long ago. The simulation results show that change from purely repulsive atomic solute interactions to include realistic attractive interactions diminishes the strength of hydrophobic bonds. For the Ar-Ar rdfs considered pointwise, the numerical results for the effects of solute attractive forces on hydrophobic interactions are opposite in sign and larger in magnitude than predicted by LMF theory. That comparison is discussed from the point of view of quasichemical theory, and it is suggested that the first reason for this difference is the incomplete evaluation within LMF theory of the hydration energy of the Ar pair. With a recent suggestion for the system-size extrapolation of the required correlation function integrals, the Ar-Ar rdfs permit evaluation of osmotic second virial coefficients B2. Those B2's also show that incorporation of attractive interactions leads to more positive (repulsive) values. With attractive interactions in play, B2 can change from positive to negative values with increasing temperatures. Furthermore, this is consistent with the puzzling suggestions of decades ago that B2 ≈ 0 for intermediate cases of temperature or solute size. In all cases here, B2 becomes more attractive with increasing temperature

  2. Attitudes, personal evaluations, cognitive evaluation and interpersonal attraction: on the direct, indirect and reverse-causal effects.

    Science.gov (United States)

    Singh, Ramadhar; Ho, Li Jen; Tan, Hui Lynn; Bell, Paul A

    2007-03-01

    The authors hypothesized that (1) attraction toward a stranger based on attitudinal similarity is automatic, but cognitive evaluation of the stranger's quality before the measurement of attraction can make attraction nonautomatic or controlled; (2) personal evaluations from the stranger activate automatic attraction and cognitive evaluation; (3) controlled attraction from attitudes and automatic attraction and cognitive evaluation from personal evaluations engender reverse-causal effects (i.e. they mediate each other); and (4) attraction and cognitive evaluation are distinct constructs. Attitudinal similarity between the participant and the stranger or personal evaluations of the former by the latter were varied in Experiment 1 (N=96), and were crossed with each other in Experiment 2 (N=240). Orders of response measurement were either cognitive evaluation followed by attraction or attraction followed by cognitive evaluation. Results confirmed the hypotheses. Implications of the findings are discussed. PMID:17355717

  3. Language in Online Dating Texts: Trait Identification, Homophily, and their Effect on Attraction.

    Science.gov (United States)

    Fox Hamilton, Nicola; Fullwood, Chris; Kirwan, Grainne

    2015-01-01

    Research has indicated that online daters may pick up on language cues connected to personality traits in online dating profile texts, and act upon those cues. This research seeks to investigate the level of accuracy of detection of personality in dating profile texts, and the extent to which perceived or actual similarity of personality has an effect on attractiveness of the author. An online survey was conducted collecting the Ten Item Personality Inventory (TIPI) for each participant and text author, a peer-report TIPI score by participants for each text author, and an attractiveness rating on a Likert scale for each author. Participants correctly identified Extraversion, though the effect size was small. Contrary to the hypotheses, participants preferred texts when written by an author with a personality they perceived as dissimilar to their own, specifically in Openness and Conscientiousness, and no relationship was found between actual similarity of personality and attractiveness. Online daters may choose partners with complementary or desirable traits rather than similar traits, or other factors in attraction may be more salient in the initial stages of determining attraction. PMID:26799890

  4. Geographic distribution and relative abundance of the invasive glassy-winged sharpshooter: effects of temperature and egg parasitoids.

    Science.gov (United States)

    Gutierrez, Andrew Paul; Ponti, Luigi; Hoddle, Mark; Almeida, Rodrigo P P; Irvin, Nicola A

    2011-08-01

    The capacity to predict the geographic distribution and relative abundance of invasive species is pivotal to developing policy for eradication or control and management. Commonly used methods fall under the ambit of ecological niche models (ENMs). These methods were reviewed and shortcomings identified. Weather-driven physiologically based demographic models (PBDMs) are proposed that resolve many of the deficiencies of ENMs. The PBDM approach is used to analyze the invasiveness of the polyphagous glassy-winged sharpshooter (Homalodisca vitripennis [Germar]), a pest native to the southeastern United States and northeastern Mexico that extended its range into California in 1989. Glassy-winged sharpshooter vectors the pathogenic bacterium, Xylella fastidiosa (Wells) that causes Pierce's disease in grape and scorch-like diseases in other plants. PBDMs for glassy-winged sharpshooter and its egg parasitoids (Gonatocerus ashmeadi Girault and G. triguttatus Girault) were developed and linked to a PBDM for grape published by Wermelinger et al. (1991). Daily weather data from 108 locations across California for the period 1995-2006 were used to drive the PBDM system, and GRASS GIS was used to map the simulation results. The geographic distribution of glassy-winged sharpshooter, as observed, is predicted to be largely restricted to the warm areas of southern California, with the action of the two egg parasitoids reducing its abundance >90%. The average indispensable mortality contributed by G. triguttatus is <1%. A temperature-dependent developmental rate model for X. fastidiosa was developed that suggests its geographic range is also limited to the warm inland areas of southern California. Biological control of glassy-winged sharpshooter further decreases the pathogen's relative range. Climate warming scenarios of +2°C and +3°C suggest that the distribution and severity of glassy-winged sharpshooter and X. fastidiosa will increase in the agriculturally rich central valley

  5. Federal tax effects on the financial attractiveness of renewable versus conventional power plants

    International Nuclear Information System (INIS)

    In this paper, we examine the effects of federal tax laws on the financial attractiveness of seven renewable and four conventional electric power generating technologies adopted by investor owned utilities (IOUs) and non-utility electricity generators (NUGs). The results show that federal income tax laws applicable to renewable generating technologies generally provide very attractive financial incentives for the adoption of these technologies by IOUs and NUGs. If an IOU and NUG is subject to the alternative minimum tax, however, it may not be able to take full advantage of these financial incentives. (author)

  6. The effect of target's physical attractiveness and dominance on STD-risk perceptions

    NARCIS (Netherlands)

    Dijkstra, P; Buunk, BP; Blanton, H

    2000-01-01

    Utilizing a 2 x 2 design, the present study examined the effect of a female's physical attractiveness and dominance on men's sexual motivation and sexually transmitted disease (STD) risk perceptions in a sample of 72 heterosexual male college students. As predicted, participants a ere more motivated

  7. Effect of spectral composition of artificial light on the attraction of moths

    NARCIS (Netherlands)

    Langevelde, van F.; Ettema, J.A.; Donners, M.; Wallis de Vries, M.F.; Groenendijk, D.

    2011-01-01

    During the last decades, artificial night lighting has increased globally, which largely affected many plant and animal species. So far, current research highlights the importance of artificial light with smaller wavelengths in attracting moths, yet the effect of the spectral composition of artifici

  8. Developing tools to eradicate ecologically destructive ants on Rose Atoll: effectiveness and attractiveness of formicidal baits

    Science.gov (United States)

    Peck, Robert; Banko, Paul; Pendleton, Frank

    2014-01-01

    A key factor contributing to the decline in the population of Pisonia grandis on Rose Atoll is an infestation of the non-native scale, Pulvinaria urbicola (Homoptera: Coccidae). Ants, in facultative relationships with scale insects, may facilitate scale population growth and increase their effect on plant hosts. Three ant species found on Rose Atoll, Tetramorium bicarinatum, T. simillimum, and Pheidole oceanica, are capable of tending Pulvinaria on Pisonia and may have contributed to the demise of the trees on the atoll. Replicated trials conducted on Rose Atoll during 17–21 March 2013 tested the effectiveness and relative attractiveness of five formicidal baits potentially to be used to eradicate these ants on the atoll. Three baits contained toxins (hydramethylnon in Amdro® and Maxforce®, indoxacarb in Provaunt®) and two baits contained an insect growth regulator (IGR; pyriproxyfen in Distance® and s-methoprene in Tango®). Amdro, Distance, and Maxforce are granular baits while Provaunt and Tango were mixed with adjuvants to form a gel-like matrix. Results varied among ant species and baits, but Provaunt was highly effective against workers of both Tetramorium species while Amdro and Maxforce were highly effective against T. simillimum and P. oceanica. Limited time on the island prevented the evaluation of the effectiveness of the IGR baits. The relative attractiveness of the baits generally mirrored their ability to kill worker ants. Tetramorium simillimum was attracted to all five baits; T. bicarinatum was attracted to Provaunt, Distance, and Tango; and P. oceanica was attracted to the three granular baits. These results and the small area of Rose Atoll suggest that island-wide application of formicidal baits may result in eradication of these ants, but an application strategy targeting all three species would more likely succeed with the use of multiple baits.

  9. Systemic Imidacloprid Affects Intraguild Parasitoids Differently.

    Science.gov (United States)

    Taylor, Sally V; Burrack, Hannah J; Roe, R Michael; Bacheler, Jack S; Sorenson, Clyde E

    2015-01-01

    Toxoneuron nigriceps (Viereck) (Hymenoptera, Braconidae) and Campoletis sonorensis (Cameron) (Hymenoptera, Ichneumonidae) are solitary endoparasitoids of the tobacco budworm, Heliothis virescens (Fabricius) (Lepidoptera, Noctuidae). They provide biological control of H. virescens populations in Southeastern US agricultural production systems. Field and greenhouse experiments conducted from 2011-2014 compared parasitism rates of parasitoids that developed inside H. virescens larvae fed on tobacco plants treated with and without imidacloprid. The parasitoids in our study did not have a similar response. Toxoneuron nigriceps had reduced parasitism rates, but parasitism rates of C. sonorensis were unaffected. Preliminary data indicate that adult female lifespans of T. nigriceps are also reduced. ELISA was used to measure concentrations of neonicotinoids, imidacloprid and imidacloprid metabolites in H. virescens larvae that fed on imidacloprid-treated plants and in the parasitoids that fed on these larvae. Concentrations were detectable in the whole bodies of parasitized H. virescens larvae, T. nigriceps larvae and T. nigriceps adults, but not in C. sonorensis larvae and adults. These findings suggest that there are effects of imidacloprid on multiple trophic levels, and that insecticide use may differentially affect natural enemies with similar feeding niches. PMID:26658677

  10. Multisensory foraging by hymenopterous parasitoids.

    OpenAIRE

    Wäckers, F.L.

    1994-01-01

    The use of parasitoids as biological control agents is gaining interest as an environmentally sound alternative to the use of chemical insecticides. In order to extend and optimize biological control systems, it is essential to gain insight in the stimuli and mechanisms by which natural enemies locate their hosts, as well as their food sources. Only then will it be possible to select the particular parasitoid or predator that constitutes the optimal fit for a given crop-pest combination, or (...

  11. Beyond personality impressions: effects of physical and vocal attractiveness on false consensus, social comparison, affiliation, and assumed and perceived similarity.

    Science.gov (United States)

    Miyake, K; Zuckerman, M

    1993-09-01

    We examined the effects of target persons' physical and vocal attractiveness on judges' responses to five measures: false consensus (the belief that the target shares one's behavior), choice of targets as comparison others, affiliation with targets, assumed similarity (similarity between self-ratings and ratings assigned to targets), and perceived similarity (direct questions about similarity). Higher physical attractiveness and higher vocal attractiveness were both related to higher scores on all variables. The effect of one type of attractiveness was more pronounced for higher levels of the other type of attractiveness. The joint effect of the two types of attractiveness was best described as synergistic, i.e., only targets high on both types of attractiveness elicited higher scores on the dependent variables. The effect of physical attractiveness on most dependent variables was more pronounced for subjects who were themselves physically attractive. The synergistic effect (the advantage of targets high on both types of attractiveness) was more pronounced for judges high in self-monitoring. The contribution of the study to the literature on attractiveness stereotypes is discussed. PMID:8246108

  12. Effects of female diet and age on offspring sex ratio of the solitary parasitoid Pachycrepoideus vindemmiae (Rondani (Hymenoptera, Pteromalidae Efeitos da dieta e idade da fêmea em relação à prole e à razão sexual do parasitoide solitário Pachycrepoideus vindemmiae (Rondani (Hymenoptera, Pteromalidae

    Directory of Open Access Journals (Sweden)

    Hao-Yuan Hu

    2012-06-01

    Full Text Available Effects of female diet and age on offspring sex ratio of the solitary parasitoid Pachycrepoideus vindemmiae (Rondani (Hymenoptera, Pteromalidae. Theories predict that females of parasitoid wasps would adjust the offspring sex ratio to environmental conditions in the oviposition patch, but the diet and age of females would also affect the sex ratio adjustment. Our focus was to test the effects of female diet and age on offspring sex ratio of the solitary parasitoid wasp, Pachycrepoideus vindemmiae (Rondani, 1875. Our results showed that females fed with honey had significantly less female biased offspring sex ratio than those fed only with water. Offspring sex ratio (male percentage decreased with female age or female longevity at the beginning of oviposition but increased at the end. There should be a sperm limitation in P. vindemmiae females at the end of oviposition, and a higher frequency of unfertilized eggs were laid then. Females also laid more unfertilized eggs at the beginning of oviposition, which would be necessary to insure the mating among offspring. Male offspring developed faster and emerged earlier, which would also reduce the risk of virginity in offspring with female-biased sex ratio.Efeitos da dieta e idade da fêmea em relação à prole e à razão sexual do parasitoide solitário Pachycrepoideus vindemmiae (Rondani (Hymenoptera, Pteromalidae. As teorias predizem que as fêmeas parasitoides de vespas ajustam a relação razão sexual dos descendentes, de acordo com condições ambientais, em cada oviposição. Entretanto, a dieta e idade das fêmeas também podem afetar o ajuste da razão sexual. Nosso foco foi testar os efeitos da dieta e idade da fêmeas em relação a razão sexual da prole da vespa parasitoide Pachycrepoideus vindemmiae (Rondani, 1875. Nossos resultados mostraram que as fêmeas alimentadas com mel apresentaram uma razão sexual significativa menor de fêmeas, do que aquelas alimentadas apenas com água. A

  13. Acoustic Attraction

    Science.gov (United States)

    Oviatt, Eric; Patsiaouris, Konstantinos; Denardo, Bruce

    2009-11-01

    A sound source of finite size produces a diverging traveling wave in an unbounded fluid. A rigid body that is small compared to the wavelength experiences an attractive radiation force (toward the source). An attractive force is also exerted on the fluid itself. The effect can be demonstrated with a styrofoam ball suspended near a loudspeaker that is producing sound of high amplitude and low frequency (for example, 100 Hz). The behavior can be understood and roughly calculated as a time-averaged Bernoulli effect. A rigorous scattering calculation yields a radiation force that is within a factor of two of the Bernoulli result. For a spherical wave, the force decreases as the inverse fifth power of the distance from the source. Applications of the phenomenon include ultrasonic filtration of liquids and the growth of supermassive black holes that emit sound waves in a surrounding plasma. An experiment is being conducted in an anechoic chamber with a 1-inch diameter aluminum ball that is suspended from an analytical balance. Directly below the ball is a baffled loudspeaker that exerts an attractive force that is measured by the balance.

  14. Angry and Beautiful: The Interactive Effect of Facial Expression and Attractiveness on Time Perception

    Directory of Open Access Journals (Sweden)

    Jasmina Tomas

    2016-07-01

    Full Text Available Time perception is an adaptive phenomenon that enables everyday functioning, although many of its aspects remain unknown. Previous studies have resulted in new insights regarding this phenomenon, indicating an overestimation of emotional faces presentations, compared to neutral ones. The aim of the present study was to explore if this effect due to emotional expression would be modulated by the attractiveness of the perceived face. Female participants performed a temporal bisection task during which they evaluated elapsed time of female faces presentation differing in facial expression (angry and neutral expression and attractiveness (attractive and unattractive face for seven different stimuli durations (400-1.600 ms. Results indicate a systematic overestimation of angry faces duration compared to neutral ones, but only for the attractive face condition, the effect that did not occur for the unattractive face. These findings support the arousal-based models of time perception, indicating that arousal affects time perception mechanism resulting in an overestimation of the perceived time.

  15. Does Ethylene Treatment Mimic the Effects of Pollination on Floral Lifespan and Attractiveness?

    OpenAIRE

    2002-01-01

    In some species pollination may result in rapid changes in perianth colour and form (petal senescence and abscission, flower closure), rendering the flowers less attractive to pollinators. It has been suggested that this effect is mediated by ethylene. Flowers from about 200 species and 50 families were exposed to ethylene (3 ppm for 24 h at 20 °C). The effects on petal senescence and abscission have been described previously. Flower closure and perianth colour changes were generally ethylene...

  16. Effects of methoxyfenozide, indoxacarb, and other insecticides on the beneficial egg parasitoid Trichogramma nr. brassicae (Hymenoptera: Trichogrammatidae) under laboratory and field conditions.

    Science.gov (United States)

    Hewa-Kapuge, Swarna; McDougall, Sandra; Hoffmann, Ary A

    2003-08-01

    Trichogramma nr. brassicae is a common egg parasitoid of Helicoverpa species in Australian processing tomatoes, but its effectiveness can be severely curtailed by insecticide applications. To identify insecticides that are potentially compatible with this species, the effects of seven insecticides, including newly introduced compounds and a surfactant, were screened in laboratory and glasshouse assays for their toxicity to the wasps. Assays involved direct applications on adults, residual effects on adults, and applications on life stages still inside the host. Methoxyfenozide and indoxacarb were not toxic to Trichogramma in any assay when applied at field rates. Naled and chlorfenapyr caused 100% mortality when directly applied to adults, and 95% mortality when adults were exposed to residues of these chemicals within 24 h of application. The effects of naled residues were short lived (Naled and chlorfenapyr were also toxic when applied to Trichogramma developing inside host eggs, reducing emergence of adults by >25%. Imidacloprid, emamectin, and tau-fluvalinate were toxic in some experiments; they caused >97% mortality in adults 1 h after direct application and in residue assays they caused 23-64% mortality during the first 24 h. In field trials, methoxyfenozide had no harmful effects on emergence from sprayed parasitized eggs, whereas indoxacarb had a small impact (<8%) on emergence. Methoxyfenozide and indoxacarb are potentially suitable for inclusion in integrated pest management strategies for management of Helicoverpa because they do not influence adult survival or development of immature stages, whereas other chemicals need to be treated cautiously. PMID:14503578

  17. Effect of residual attractive interactions in size asymmetric colloidal mixtures: Theoretical analysis and predictions.

    Science.gov (United States)

    Germain, Ph

    2010-07-28

    We analyze the influence of residual attractions on the static and some dynamic properties of size asymmetric mixtures of "hard-sphere-like" colloids. These attractions, usually neglected in the theoretical analysis, are characterized by a very short range and a moderate strength reflecting the underlying microscopic structure of the colloidal particles. Their effect on the potentials of mean force is analyzed from analytical expressions obtained from low density expansions. The effective potential of the big particle fluid is next considered. An analytical expression is proposed for estimating the deviation with respect to the hard sphere depletion potential. This case is compared to that of mixtures with noninteracting depletants. The important consequences on the binodals and the glass transition lines of the effective fluid are discussed in both cases. This study is next extended to other properties-the specific heat and the low shear viscosity-which incorporate contributions from the two components of the binary mixture. PMID:20687684

  18. Effect of residual attractive interactions in size asymmetric colloidal mixtures: Theoretical analysis and predictions

    Science.gov (United States)

    Germain, Ph.

    2010-07-01

    We analyze the influence of residual attractions on the static and some dynamic properties of size asymmetric mixtures of "hard-sphere-like" colloids. These attractions, usually neglected in the theoretical analysis, are characterized by a very short range and a moderate strength reflecting the underlying microscopic structure of the colloidal particles. Their effect on the potentials of mean force is analyzed from analytical expressions obtained from low density expansions. The effective potential of the big particle fluid is next considered. An analytical expression is proposed for estimating the deviation with respect to the hard sphere depletion potential. This case is compared to that of mixtures with noninteracting depletants. The important consequences on the binodals and the glass transition lines of the effective fluid are discussed in both cases. This study is next extended to other properties—the specific heat and the low shear viscosity—which incorporate contributions from the two components of the binary mixture.

  19. Partial aphid resistance in lettuce negatively affects parasitoids.

    Science.gov (United States)

    Lanteigne, Marie-Eve; Brodeur, Jacques; Jenni, Sylvie; Boivin, Guy

    2014-10-01

    This study investigated the effects of partial plant resistance on the lettuce aphid Nasonovia ribisnigri (Mosley) (Hemiptera: Aphididae), a major pest of cultivated lettuce (Lactuca sativa L.), and one of its parasitoids, Aphidius ervi Haliday (Hymenoptera: Braconidae). Aphids were reared on susceptible (L. sativa variety Estival; S) or partially resistant (Lactuca serriola L. PI 491093; PR) lettuce, and next parasitized by A. ervi females. Fitness proxies were measured for both aphids and parasitoids. Developmental time to adult stage took longer for alate and apterous aphids (an average of 3.5 and 1.5 additional days, respectively) on PR than on S lettuce, and fecundity of alate aphids reared on PR lettuce was reduced by 37.8% relative to those reared on S lettuce. Size (tibia length) and weight of aphids reared on PR lettuce were lower than for aphids reared on S lettuce from the third and second instar onward, respectively. Parasitism of aphids reared on PR plants resulted in lower parasitoid offspring emergence (-49.9%), lower adult female (-30.3%) and male (-27.5%) weight, smaller adult female (-17.5%) and male (-11.9%) size, and lower female fecundity (37.8% fewer eggs) than when parasitoids developed from aphids reared on S plants. Our results demonstrate that partial aphid resistance in lettuce negatively affects both the second and third trophic levels. Host plant resistance in cultivated lettuce may therefore create an ecological sink for aphid parasitoids. PMID:25197882

  20. Inverted Cheerios effect: Liquid drops attract or repel by elasto-capillarity

    CERN Document Server

    Karpitschka, S; Lubbers, L A; Weijs, J H; Botto, L; Das, S; Andreotti, B; Snoeijer, J H

    2016-01-01

    Solid particles floating at a liquid interface exhibit a long-ranged attraction mediated by surface tension. In the absence of bulk elasticity, this is the dominant lateral interaction of mechanical origin. Here we show that an analogous long-range interaction occurs between adjacent droplets on solid substrates, which crucially relies on a combination of capillarity and bulk elasticity. We experimentally observe the interaction between droplets on soft gels and provide a theoretical framework that quantitatively predicts the migration velocity of the droplets. Remarkably, we find that while on thick substrates the interaction is purely attractive and leads to drop-drop coalescence, for relatively thin substrates a short-range repulsion occurs which prevents the two drops from coming into direct contact. This versatile, new interaction is the liquid-on-solid analogue of the "Cheerios effect". The effect will strongly influence the condensation and coarsening of drop soft polymer films, and has potential impli...

  1. Effect of Mono- and Multivalent Salts on Angle-dependent Attractions between Charged Rods

    OpenAIRE

    Lee, Kun-Chun; Borukhov, Itamar; Gelbart, William M.; Liu, Andrea J.; Stevens, Mark J.

    2003-01-01

    Using molecular dynamics simulations we examine the effective interactions between two like-charged rods as a function of angle and separation. In particular, we determine how the competing electrostatic repulsions and multivalent-ion-induced attractions depend upon concentrations of simple and multivalent salt. We find that with increasing multivalent salt the stable configuration of two rods evolves from isolated rods to aggregated perpendicular rods to aggregated parallel rods; at sufficie...

  2. Impact of Rag1 aphid resistant soybeans on Binodoxys communis (Hymenoptera: Braconidae), a parasitoid of soybean aphid (Hemiptera: Aphididae).

    Science.gov (United States)

    Ghising, Kiran; Harmon, Jason P; Beauzay, Patrick B; Prischmann-Voldseth, Deirdre A; Helms, Ted C; Ode, Paul J; Knodel, Janet J

    2012-04-01

    Multiple strategies are being developed for pest management of the soybean aphid, Aphis glycines Matsumura; however, there has been little published research thus far to determine how such strategies may influence each other, thereby complicating their potential effectiveness. A susceptible soybean (Glycine max L.) variety without the Rag1 gene and a near isogenic resistant soybean variety with the Rag1 gene were evaluated in the laboratory for their effects on the fitness of the soybean aphid parasitoid, Binodoxys communis (Gahan). The presence or absence of the Rag1 gene was verified by quantifying soybean aphid growth. To test for fitness effects, parasitoids were allowed to attack soybean aphids on either a susceptible or resistant plant for 24 h and then aphids were kept on the same plant throughout parasitoid development. Parasitoid fitness was measured by mummy and adult parasitoid production, adult parasitoid emergence, development time, and adult size. Parasitoids that attacked soybean aphids on susceptible plants produced more mummies, more adult parasitoids, and had a higher emergence rate compared with those on resistant plants. Adult parasitoids that emerged from resistant plants took 1 d longer and were smaller compared with those from susceptible plants. This study suggests that biological control by B. communis may be compromised when host plant resistance is widely used for pest management of soybean aphids. PMID:22507000

  3. The parasitoids of the asparagus miner (Diptera: Agromyzidae): field parasitism and the influence of food resources on life history.

    Science.gov (United States)

    Morrison, William R; Gibson, Gary A P; Szendrei, Zsofia

    2014-12-01

    The goals of this study were to identify pupal parasitoids of the asparagus miner, Ophiomyia simplex Loew (Diptera: Agromyzidae), and examine the effect of different diets and floral resources on the lifespan of adult asparagus miners and their parasitoids. We also measured the effect of parasitism on stem damage caused by the asparagus miner. The identity and abundance of the parasitoids of the asparagus miner were determined in asparagus fields in Michigan from weekly asparagus miner pupal collections during the 2010-2013 seasons. Twelve species of hymenopterous parasitoids were reared from asparagus miner pupae, including Chorebus rondanii (Giard) (Ichneumonoidea: Braconidae), 10 species in three families of Chalcidoidea, and one species of Bethylidae (Chrysidoidea), that represent new host records for the asparagus miner. C. rondanii and Thinodytes cephalon (Walker) (Pteromalidae) were the most common parasitoids. The effects of different diets and flowers on the lifespan of the pest and parasitoid adults were also evaluated. Buckwheat resulted in the shortest life span for the asparagus miner, whereas Riddell's goldenrod significantly increased its lifespan relative to the control. Parasitoid lifespan was doubled when individuals were fed sugar-rich diets. In the field, parasitoids preferred stems that contained more pupae and damage. The two most commonly reared parasitoids should be considered as targets for future conservation biological control efforts of the asparagus miner. PMID:25313948

  4. The Effects of Physical Attractiveness and Ethnicity on Children's Behavioral Attributions and Peer Preferences

    Science.gov (United States)

    Langlois, Judith H.; Stephan, Cookie

    1977-01-01

    Investigates the generality of stereotypes associated with physical attractiveness and assesses the relative contributions of attractiveness and ethnicity in determining children's behavioral attributions and peer preferences. (JMB)

  5. Insecticidal Effect of Chrysanthemum coronarium L. Flowers on the Pest Spodoptera littoralis Boisd and its Parasitoid Microplitis rufiventris Kok. with Identifying the Chemical Composition

    Science.gov (United States)

    Shonouda, Mourad L.; Osman, Salah; Salama, Osama; Ayoub, Amal

    The flower extract of Chrysanthemum coronarium L. and their fractions have shown insecticidal effect on the cotton leaf worm Spodoptera littoralis. The third instar larvae fed for two days on treated leaves were more susceptible to plant extracts and to their ethyl acetate and chloroform fractions. The active lowest concentration (5%) of the flower fractions showed no significant effect on the percent reduction of emerged adult parasitoids, Microplitis rufiventris Kok. GC/MS analysis revealed that the major constituents in ethyl acetate fraction were 3-dihydro-methylene-2- (3H) furanone (17.8%), jasmolin I (15.6%), carveol 1 (13.6%), phosphoric acid, tributyl ester (11.4%) and cinerin II (11.1%), while those of chloroform fraction were 5-hydroxy-3 methyl-1H-pyrazole (42.7%) and carveol 1(24.8%). The medicinal plant C. coronarium seems to be a promising plant for application in integrated pest management due to its safety to the surrounding environment.

  6. Determinants of parasitoid communities of willow-galling sawflies: habitat overrides physiology, host plant and space.

    Science.gov (United States)

    Nyman, Tommi; Leppänen, Sanna A; Várkonyi, Gergely; Shaw, Mark R; Koivisto, Reijo; Barstad, Trond Elling; Vikberg, Veli; Roininen, Heikki

    2015-10-01

    Studies on the determinants of plant-herbivore and herbivore-parasitoid associations provide important insights into the origin and maintenance of global and local species richness. If parasitoids are specialists on herbivore niches rather than on herbivore taxa, then alternating escape of herbivores into novel niches and delayed resource tracking by parasitoids could fuel diversification at both trophic levels. We used DNA barcoding to identify parasitoids that attack larvae of seven Pontania sawfly species that induce leaf galls on eight willow species growing in subarctic and arctic-alpine habitats in three geographic locations in northern Fennoscandia, and then applied distance- and model-based multivariate analyses and phylogenetic regression methods to evaluate the hierarchical importance of location, phylogeny and different galler niche dimensions on parasitoid host use. We found statistically significant variation in parasitoid communities across geographic locations and willow host species, but the differences were mainly quantitative due to extensive sharing of enemies among gallers within habitat types. By contrast, the divide between habitats defined two qualitatively different network compartments, because many common parasitoids exhibited strong habitat preference. Galler and parasitoid phylogenies did not explain associations, because distantly related arctic-alpine gallers were attacked by a species-poor enemy community dominated by two parasitoid species that most likely have independently tracked the gallers' evolutionary shifts into the novel habitat. Our results indicate that barcode- and phylogeny-based analyses of food webs that span forested vs. tundra or grassland environments could improve our understanding of vertical diversification effects in complex plant-herbivore-parasitoid networks. PMID:26340615

  7. Mainstreaming hearing-impaired students: the effect of effort in communicating on cooperation and interpersonal attraction.

    Science.gov (United States)

    Johnson, D W; Johnson, R T

    1985-01-01

    Cooperative and individualistic learning experiences were compared in terms of their effects on interaction and relationships between hearing and hearing-impaired students. Two contradictory hypotheses were tested--one stating that the effort required for hearing and hearing-impaired students to communicate would lead to frustration, withdrawal, exclusion, and rejection; the other stating that cooperative learning experiences would lead to cross-handicap interpersonal attraction regardless of communication difficulties. Thirty 3rd-grade students (20 hearing and 10 hearing impaired) were assigned to conditions on a stratified, random basis controlling for handicap, sex, and ability level. They participated in the study for 55 min a day for 15 instructional days. The results indicate that subjects involved in cooperative learning experiences performed higher on measures of interaction and interpersonal attraction between hearing and hearing-impaired students than did subjects involved in individualistic learning experiences. PMID:3989740

  8. Biologia da traça das crucíferas, Plutella xylostella Linnaeus (Lepidoptera, Yponomeutidae, sob condições controladas de temperatura, e parasitóides associados: Part III. Estudo sobre a biologia de Apanteles piceotrichosus (Blanchard (Hymenoptera, Braconidae: análise do efeito de endocruzamento Biology of crucifer moth, Plutella xylostella Linnaeus (Lepidoptera, Yponomeutidae, under controlled temperature conditions, and parasitoids associated.: Part III. Study on the biology of Apanteles piceotrichosus (Blanchard (Hymenoptera, Braconidae: analysis of the inbreeding effect

    Directory of Open Access Journals (Sweden)

    Rafaelle R. Gonçalves

    2005-09-01

    Full Text Available O endocruzamento em populações naturais resulta em uma perda na variabilidade genética que pode influenciar, a mortalidade juvenil e adulta, o tamanho, a viabilidade e fertilidade da prole, bem como a morfologia dos indivíduos. Apanteles piceotrichosus (Blanchard, 1943 (Hymenoptera, Braconidae é um parasitóide de Plutella xylostella Linnaeus,1758 (Lepidoptera, Yponomeutidae que tem atraído muita atenção com o propósito de biocontrole, pois pode ser utilizado como agente de controle biológico. Para a criação e liberação destes indivíduos são necessários estudos sobre a sua biologia. O objetivo do presente estudo foi examinar o efeito do endocruzamento sobre a mortalidade, longevidade e proporção sexual de A. piceotrichosus. Também foi observada a taxa de ataque do parasitóide sobre o hospedeiro. Foram realizados cruzamentos programados, a partir de indivíduos coletados em campo e criados em laboratório sob condições controladas. Não foram observadas diferenças significantes na mortalidade e na longevidade de A. piceotrichosus, bem como na taxa de ataque do parasitóide sobre o hospedeiro. A proporção sexual apresentou diferenças significantes entre o grupo controle e o endocruzado,entretanto não foram observadas diferenças dentro do grupo endocruzados.The inbreeding in natural populations results in a loss in the genetic variability that can influence juvenile and adult mortality, the size, viability and fertility of the offspring, as well as the individuals morphology. Apanteles piceotrichosus (Blanchard, 1943 (Hymenoptera, Braconidae is a Plutella xylostella Linnaeus,1758 parasitoid (Lepidoptera, Yponomeutidae that has been attracting a lot of attention to a biocontrol purpose, because it can be used as agent of biological control. For the creation and liberation of parasitoids are necessary studies on its biology. The objective of the present study was carried out to examine the inbreeding effect on the

  9. Effects of the host and parasitoid densities on the quality production of Trichogramma chilonis on lepidopterous (Sitotroga cereallela and Corcyra cephalonica eggs

    Directory of Open Access Journals (Sweden)

    Farzana Perveen

    2012-06-01

    Full Text Available The present study was conducted for efficient and quality production of the stingless wasp, Trichogramma chilonis Ishii with respect to rearing host and parasitoid densities of the angoumois grain moth, Sitotroga cereallela (Olivier and the rice meal moth, Corcyra cephalonica (Stainton on its biology. For host density,percentage parasitism and adult longevity was the highest at 20 eggs whereas emergence was the highest from 10 eggs of S. cereallela while of C. cephalonica percentage parasitism and emergence was the highest at 10 eggs. For parasitoid density, parasitism was the highest at 5 pairs of T. chilonis. Percentage of emergence and longevity remained similar among all the 5 treatments. It is concluded that S. cereallela eggs more suitable as compare to C. cephalonica eggs for mass and quality rearing of parasitoid, T. chilonis.

  10. Annual dynamics of wild bee densities: attractiveness and productivity effects of oilseed rape.

    Science.gov (United States)

    Riedinger, Verena; Mitesser, Oliver; Hovestadt, Thomas; Steffan-Dewenter, Ingolf; Holzschuh, Andrea

    2015-05-01

    Mass-flowering crops may affect long-term population dynamics, but effects on pollinators have never been studied across several years. We monitored wild bees in oilseed rape fields in 16 landscapes in Germany in two consecutive years. Effects on bee densities of landscape oilseed rape cover in the years of monitoring and in the previous years were evaluated with landscape data from three consecutive years. We fit empirical data to a mechanistic model to provide estimates for oilseed rape attractiveness and its effect on bee productivity in comparison to the rest of the landscape, and we evaluated consequences for pollinator densities in consecutive years. Our results show that high oilseed rape cover in the previous year enhances current densities of wild bees (except for bumble bees). Moreover, we show a strong attractiveness of and dilution on (i.e., decreasing bee densities with increasing landscape oilseed rape cover) oilseed rape for bees during flowering in the current year, modifying the effect of the previous year's oilseed rape cover in the case of wild bees (excluding Bombus). As long as other factors such as nesting sites or natural enemies do not limit bee reproduction, our findings suggest long-term positive effects of mass-flowering crops on bee populations, at least for non-Bombus generalists, which possibly help to maintain crop pollination services even when crop area increases. Similar effects are conceivable for other organisms providing ecosystem services in annual crops and should be considered in future studies. PMID:26236848

  11. Effect of Spatial Repellent Exposure on Dengue Vector Attraction to Oviposition Sites

    Science.gov (United States)

    Grieco, John P.; Apperson, Charles S.; Schal, Coby; Ponnusamy, Loganathan; Wesson, Dawn M.; Achee, Nicole L.

    2016-01-01

    Background Aedes aegypti is a primary vector of dengue virus (DENV), the causative agent of dengue fever, an arthropod-borne disease of global importance. Although a vaccine has been recommended for prevention, current dengue prevention strategies rely on vector control. Recently, volatile pyrethroids—spatial repellents—have received interest as a novel delivery system for adult Ae. aegypti control. Understanding the full range of behavioral effects spatial repellents elicit in mosquito species will be critical to understanding the overall impact these products have on vector populations and will guide expectations of efficacy against DENV transmission. Methodology/Principal Findings The current study quantified changes in attraction of gravid Ae. aegypti to experimental oviposition sites following exposure to the spatial repellent transfluthrin. Responses were measured with two-choice olfaction bioassays using ‘sticky-screens’ covering cups to prevent contact with the oviposition substrate. Two cups contained a bacterial attractant composed of four species of bacteria in calcium alginate beads in water and two cups contained only deionized water. Results from 40 replicates (n = 780 females total per treatment) indicated an estimated difference in attraction of 9.35% ± 0.18 (p ≤ 0.003), implying that the transfluthrin-exposed mosquitoes were more attracted to the experimental oviposition sites than the non-exposed mosquitoes. Conclusions/Significance Findings from this study will further characterize the role of spatial repellents to modify Ae. aegypti behavior related to dengue prevention specifically, and encourage innovation in vector control product development more broadly. PMID:27428011

  12. Name-valence and physical attractiveness in Facebook: their compensatory effects on friendship acceptance.

    Science.gov (United States)

    Greitemeyer, Tobias; Kunz, Irene

    2013-01-01

    Name-valence and physical attractiveness have been shown to be associated with how people respond toward others, in that people judge and behave more positively toward individuals with positive names and individuals who are physically attractive. The present research examined whether Facebook users are more likely to accept friendship requests from other Facebook users with positive (relative to negative) names and who are physically attractive (relative to being moderately attractive). In fact, both name-valence and physical attractiveness affected friendship acceptance. Moreover, results revealed that name-valence can be compensated by physical attractiveness (and vice versa). Acceptance rates of requests from users with positive names who are moderately attractive, as well as requests from users with negative names who are attractive did not significantly differ from those with positive names who are attractive. PMID:23724699

  13. No evidence for increased extinction proneness with decreasing effective population size in a parasitoid with complementary sex determination and fertile diploid males

    Directory of Open Access Journals (Sweden)

    Mazzi Dominique

    2010-11-01

    Full Text Available Abstract Background In species with single locus complementary sex determination (sl-CSD, the sex of individuals depends on their genotype at one single locus with multiple alleles. Haploid individuals are always males. Diploid individuals are females when heterozygous, but males when homozygous at the sex-determining locus. Diploid males are typically unviable or effectively sterile, hence imposing a genetic load on populations. Diploid males are produced from matings of partners that share an allele at the sex-determining locus. The lower the allelic diversity at the sex-determining locus, the more diploid males are produced, ultimately impairing the growth of populations and jeopardizing their persistence. The gregarious endoparasitoid wasp Cotesia glomerata is one of only two known species with sl-CSD and fertile diploid males. Results By manipulating the relatedness of the founders, we established replicated experimental populations of the parasitoid C. glomerata differing in their genetic effective size, and thus in allelic richness at the sex-determining locus and in the expected magnitude of diploid male production. Our long-term survey of population welfare and persistence did not provide evidence for increased proneness to population extinction with decreasing initial genetic effective population size. Most recorded surrogates of fitness nevertheless decayed over time and most experimental populations eventually went extinct, suggesting that the negative effects of inbreeding outweighed any premium from the fertility of diploid males. Conclusions The fertility of diploid males may have evolved as an adaptation prompted by the risk of extinction looming over small isolated populations of species with sl-CSD. However, fertility of diploid males does not negate the costs imposed by their production, and although it may temporarily stave off extinction, it is not sufficient to eradicate the negative effects of inbreeding.

  14. Evaluación de algunos insecticidas para el control de la «polilla del tomate», Tuta absoluta (Lepidoptera: Gelechiidae y su efecto residual sobre el parasitoide Trichogrammatoidea bactrae (Hymenoptera: Trichogrammatidae Efficacy of insecticides against the «tomato moth», Tuta absoluta (Lepidoptera: Gelechiidae and their residual effects on the parasitoid Trichogrammatoidea bactrae (Hymenoptera: Trichogrammatidae

    Directory of Open Access Journals (Sweden)

    María B. Riquelme Virgala

    2006-12-01

    Full Text Available La «polilla del tomate», Tuta absoluta (Meyrick, es una plaga clave de este cultivo en Argentina. Su manejo integrado debería incluir una selección de productos fitosanitarios que sean eficaces para su control y, al mismo tiempo, selectivos respecto de sus enemigos naturales. El objetivo de este trabajo fue evaluar la capacidad de control de los insecticidas triflumurón, clorfenapir, abamectin y una cepa experimental de Bacillus thuringiensis (Bt sobre la plaga, y el poder residual de los mismos sobre Trichogrammatoidea bactrae Nagaraja. Se registró la mortalidad de la polilla cada cuatro días, desde la aplicación hasta la emergencia de los adultos. El efecto sobre el parasitoide, se evaluó a través del número de huevos parasitados por hembra expuesta durante 48 horas a folíolos tratados, y su mortalidad luego de 1, 3, 7, 14 y 30 días de la pulverización. Todos los productos ocasionaron una mortalidad de T. absoluta mayor al 65% después de 12 días de aplicados. El Bt fue el único insecticida que no afectó la supervivencia y el parasitismo de T. bactrae . Estos resultados aportan información de interés para la selección de plaguicidas, a emplearse en programas de manejo integrado.The «tomato moth», Tuta absoluta (Meyrick is one of the key pests of tomato crops in Argentina. The compatible use of chemical and biological control is the main purpose of integrated pest management. Selective pesticides that can be successfully used to control pest without adverse side effects on natural enemies are highly required. The aim of this work was to evaluate the efficacy of control of T. absoluta and the residual effect on the oophagous parasitoid, Trichogrammatoidea bactrae Nagaraja of the following insecticides: triflumuron, abamectin, chlorfenapyr, and an experimental strain of Bacillus thuringiensis (Bt. Mortality of T. absoluta was evaluated every 4 days from pesticide spraying until adult emergency. The effect of pesticides on

  15. Tritrophic interaction among host plants, whiteflies, and parasitoids

    Science.gov (United States)

    Laboratory experiments were conducted to compare effects of cotton, bean, sweet potato, and tomato on the mortality and development of Bemisia tabaci (Gennadius) biotype B, Traileurodes abutilonea (Haldeman), and T. vaporariorum (Westwood) and on the key biological parameters of an exotic parasitoid...

  16. Rubbernecking Effect of Intimate Information on Twitter: When Getting Attention Works Against Interpersonal Attraction.

    Science.gov (United States)

    Baruh, Lemi; Cemalcılar, Zeynep

    2015-09-01

    Social networking sites offer individuals an opportunity to document and share information about themselves, as well as engaging in social browsing to learn about others. As a micro-blogging site within which users often share information publicly, Twitter may be a particularly suitable venue that can help satisfy both of these motivations. This study investigates how viewers react to disclosure of intimate information on Twitter. Specifically, the impact of disclosure intimacy is studied on attention that viewers pay to a Twitter page, reduction in their uncertainty about the attributes of the page owner, and their interpersonal attraction to the owner of the page. A total of 618 adult online panel members viewed one of six Twitter pages that contained either low-intimacy or high-intimacy tweets. Analyses indicated that viewers exposed to the Twitter pages containing high-intimate information paid more attention to the pages, were more confident about the attributions they could make about the page owner, yet were less willing to pursue further socialization with the page owner. Furthermore, attributional confidence mediated and perceived similarity moderated the relationship between disclosure intimacy and interpersonal attraction. This interaction between disclosure intimacy and perceived similarity was such that viewers who considered the page owner to be similar (dissimilar) to themselves were more (less) socially attracted to page owners who disclosed intimate information. These findings suggest that while intimate information shared on a Twitter page draws attention, this does not necessarily result in further socialization with the page owner--an effect we named as the "rubbernecking effect" of intimate information. PMID:26348810

  17. Some Effects of Attitudinal Similarity and Exposure on Attraction and Aggression

    Science.gov (United States)

    Shuntich, Richard J.

    1976-01-01

    Previous research investigating the relationship of attraction and aggression has yielded somewhat equivocal results. The present study investigated the influence of two variables, attitudinal similarity and exposure, on interpersonal attraction and physical aggression. (Editor)

  18. The effects of facial adiposity on attractiveness and perceived leadership ability

    OpenAIRE

    Re, Daniel Edward; Perrett, David Ian

    2014-01-01

    Facial attractiveness has a positive influence on electoral success both in experimental paradigms and in the real world. One parameter that influences facial attractiveness and social judgements is facial adiposity (a facial correlate to body mass index, BMI). Overweight people have high facial adiposity and are perceived to be less attractive and lower in leadership ability. Here, we used an interactive design in order to assess whether the most attractive level of facial adiposity is also ...

  19. Effects of Applicant Sex, Physical Attractiveness, and Type of Job on Employment Interviewers' Decisions.

    Science.gov (United States)

    Gilmore, David C.; And Others

    Past research on the employment interview has suggested that interviewers are influenced by many variables, including physical attractiveness. To investigate the potential interaction of applicant sex and attractiveness on hiring decisions, the type of job, applicant sex, and applicant physical attractiveness were manipulated to determine the…

  20. The Effect of Attractive Interactions and Macromolecular Crowding on Crystallins Association.

    Directory of Open Access Journals (Sweden)

    Jiachen Wei

    Full Text Available In living systems proteins are typically found in crowded environments where their effective interactions strongly depend on the surrounding medium. Yet, their association and dissociation needs to be robustly controlled in order to enable biological function. Uncontrolled protein aggregation often causes disease. For instance, cataract is caused by the clustering of lens proteins, i.e., crystallins, resulting in enhanced light scattering and impaired vision or blindness. To investigate the molecular origins of cataract formation and to design efficient treatments, a better understanding of crystallin association in macromolecular crowded environment is needed. Here we present a theoretical study of simple coarse grained colloidal models to characterize the general features of how the association equilibrium of proteins depends on the magnitude of intermolecular attraction. By comparing the analytic results to the available experimental data on the osmotic pressure in crystallin solutions, we identify the effective parameters regimes applicable to crystallins. Moreover, the combination of two models allows us to predict that the number of binding sites on crystallin is small, i.e. one to three per protein, which is different from previous estimates. We further observe that the crowding factor is sensitive to the size asymmetry between the reactants and crowding agents, the shape of the protein clusters, and to small variations of intermolecular attraction. Our work may provide general guidelines on how to steer the protein interactions in order to control their association.

  1. Multisensory foraging by hymenopterous parasitoids.

    NARCIS (Netherlands)

    Wäckers, F.L.

    1994-01-01

    The use of parasitoids as biological control agents is gaining interest as an environmentally sound alternative to the use of chemical insecticides. In order to extend and optimize biological control systems, it is essential to gain insight in the stimuli and mechanisms by which natural enemies loca

  2. Fatal attraction

    DEFF Research Database (Denmark)

    Jensen, Kim Ebensgaard

    2012-01-01

    of the use of the Danish ihjel-construction which accounts for patterns of attraction of construction-verb attraction, patterns of productivity, and various types of subconstructions, including item- and item-class-based ones and metaphorical extensions. The description of the ihjel...

  3. The combined effect of attraction and orientation zones in 2D flocking models

    Science.gov (United States)

    Iliass, Tarras; Cambui, Dorilson

    2016-01-01

    In nature, many animal groups, such as fish schools or bird flocks, clearly display structural order and appear to move as a single coherent entity. In order to understand the complex motion of these systems, we study the Vicsek model of self-propelled particles (SPP) which is an important tool to investigate the behavior of collective motion of live organisms. This model reproduces the biological behavior patterns in the two-dimensional (2D) space. Within the framework of this model, the particles move with the same absolute velocity and interact locally in the zone of orientation by trying to align their direction with that of the neighbors. In this paper, we model the collective movement of SPP using an agent-based model which follows biologically motivated behavioral rules, by adding a second region called the attraction zone, where each particles move towards each other avoiding being isolated. Our main goal is to present a detailed numerical study on the effect of the zone of attraction on the kinetic phase transition of our system. In our study, the consideration of this zone seems to play an important role in the cohesion. Consequently, in the directional orientation, the zone that we added forms the compact particle group. In our simulation, we show clearly that the model proposed here can produce two collective behavior patterns: torus and dynamic parallel group. Implications of these findings are discussed.

  4. Positive correlation of methamidophos resistance between Lipaphis erysimi and Diaeretilla rapae and effects of methamidophos ingested by host insect on the parasitoid

    Institute of Scientific and Technical Information of China (English)

    Gang Wu; Yong-Wen Lin; Tadashi Miyata; Shu-Ren Jiang; Lian-Hui Xie

    2009-01-01

    Temporal and spatial correlated variations on the methamidophos resistance and biomolecular rate constant of acetylcholinesterase to insecticides were found between the turnip aphid, Lipaphis erysimi and its endoparasitoid, Diaeretilla rapae, collected from field colonies and an insecticide-free field insectarium in Fujian, China. Compared to the related susceptible iusectarium population, L. erysimi and D. rapae displayed 7.4-29.2- and 2.6-9.2-fold resistance ratios, respectively. In addition, two populations of L. erysimi with different methamidophos resistance levels, that is, a field (with 5.8-fold resistance ratio) and an insectarium population, were used to study the effects of methamidophos ingested by the host insect on D. rapae development. The percentage of D. rapae cocoon formation decreased significantly when the parasitized L. erysimi were fed on cauliflower leaves treated with methamidophos at lethal concentration dosages 10 (LC10) or LC50. At LC50 dosages the percentage of D. rapae cocoon formation and adult emergence decreased significantly. When the parasitized L. erysimi were fed on methamidophos at LC50 dosage, no D. rapae cocoons were found. When the field or insectarium L. erysimi were treated with methamidophos at LC10, the susceptibility to methamidophos in the adult D. rapae emerged from the treated host insect was similar to the control. However, the susceptibility to methamidophos in the adult D. rapae became lower than the control when the host insects were treated at LC50 dosages. The data thus suggested that the methamidophos ingested by the host insect L. erysimi could be an important factor in the endoparasitoids' insecticide resistance development. The natural selectivity would favor the parasitoids that had developed an insensitivity to the insecticide(s).

  5. The effect of snowdrop lectin (GNA) delivered via artificial diet and transgenic plants on Eulophus pennicornis (Hymenoptera: Eulophidae), a parasitoid of the tomato moth Lacanobia oleracea (Lepidoptera: Noctuidae).

    Science.gov (United States)

    Bell, H A.; Fitches, E C.; Down, R E.; Marris, G C.; Edwards, J P.; Gatehouse, J A.; Gatehouse, A M.R.

    1999-11-01

    Snowdrop lectin (Galanthus nivalis agglutinin, GNA) has previously been shown to confer significant levels of protection against the lepidopteran pest Lacanobia oleracea when expressed in transgenic potato. The effect of GNA on the parasitism of L. oleracea by the gregarious ectoparasitoid Eulophus pennicornis was investigated. Maize-based, and potato leaf-based diets containing GNA, and excised transgenic potato leaves expressing GNA, were fed to L. oleracea larvae from the beginning of either the third or fourth larval instar. Lacanobia oleracea larvae were individually exposed to single mated adult female E. pennicornis parasitoids from the fifth instar onwards.The success of the wasp was not reduced by the presence of GNA in any of the diets, or by the length of feeding of the host prior to parasitism. However, the mean number of wasps that developed on L. oleracea reared from the third instar on the GNA-containing maize diet was significantly higher than on the controls (20.6 and 9.3 adults/host respectively). In all other cases differences were not significant. Eulophus pennicornis progeny that developed on L. oleracea reared on GNA-containing diets showed little or no alteration in size, longevity, egg load and fecundity when compared with wasps that had developed on hosts fed the respective control diets.The results suggest that expression of GNA in transgenic crops to confer resistance to lepidopteran pests will not adversely affect the ability of the ectoparasitoid E. pennicornis to utilise the pest species as a host. PMID:12770273

  6. Sequential effects in judgements of attractiveness: the influences of face race and sex.

    Directory of Open Access Journals (Sweden)

    Robin S S Kramer

    Full Text Available In perceptual decision-making, a person's response on a given trial is influenced by their response on the immediately preceding trial. This sequential effect was initially demonstrated in psychophysical tasks, but has now been found in more complex, real-world judgements. The similarity of the current and previous stimuli determines the nature of the effect, with more similar items producing assimilation in judgements, while less similarity can cause a contrast effect. Previous research found assimilation in ratings of facial attractiveness, and here, we investigated whether this effect is influenced by the social categories of the faces presented. Over three experiments, participants rated the attractiveness of own- (White and other-race (Chinese faces of both sexes that appeared successively. Through blocking trials by race (Experiment 1, sex (Experiment 2, or both dimensions (Experiment 3, we could examine how sequential judgements were altered by the salience of different social categories in face sequences. For sequences that varied in sex alone, own-race faces showed significantly less opposite-sex assimilation (male and female faces perceived as dissimilar, while other-race faces showed equal assimilation for opposite- and same-sex sequences (male and female faces were not differentiated. For sequences that varied in race alone, categorisation by race resulted in no opposite-race assimilation for either sex of face (White and Chinese faces perceived as dissimilar. For sequences that varied in both race and sex, same-category assimilation was significantly greater than opposite-category. Our results suggest that the race of a face represents a superordinate category relative to sex. These findings demonstrate the importance of social categories when considering sequential judgements of faces, and also highlight a novel approach for investigating how multiple social dimensions interact during decision-making.

  7. Leaf-Cutter Ant Parasitoids: Current Knowledge

    OpenAIRE

    Patricia J. Folgarait

    2013-01-01

    This review updates and summarizes the current knowledge about the interaction of leaf-cutter ants and their parasitoids by providing comparable data for Acromyrmex and Atta ants. First, an overview of the relevant aspects of the biology and taxonomy of leaf cutters and of their parasitoids is provided. Second, I show the peculiarities of the parasitoids attacking behaviors towards their host as well as the responses or ant defenses against the phorids exhibited by their hosts. Third, I discu...

  8. Evidence for specificity in symbiont-conferred protection against parasitoids.

    Science.gov (United States)

    McLean, Ailsa H C; Godfray, H Charles J

    2015-07-22

    Many insects harbour facultative symbiotic bacteria, some of which have been shown to provide resistance against natural enemies. One of the best-known protective symbionts is Hamiltonella defensa, which in pea aphid (Acyrthosiphon pisum) confers resistance against attack by parasitoid wasps in the genus Aphidius (Braconidae).We asked (i) whether this symbiont also confers protection against a phylogenetically distant group of parasitoids (Aphelinidae) and (ii) whether there are consistent differences in the effects of bacteria found in pea aphid biotypes adapted to different host plants. We found that some H. defensa strains do provide protection against an aphelinid parasitoid Aphelinus abdominalis. Hamiltonella defensa from the Lotus biotype provided high resistance to A. abdominalis and moderate to low resistance to Aphidius ervi, while the reverse was seen from Medicago biotype isolates. Aphids from Ononis showed no evidence of symbiont-mediated protection against either wasp species and were relatively vulnerable to both. Our results may reflect the different selection pressures exerted by the parasitoid community on aphids feeding on different host plants, and could help explain the maintenance of genetic diversity in bacterial symbionts. PMID:26136451

  9. The Price of Being Beautiful: Negative Effects of Attractiveness on Empathy for Children in Need

    OpenAIRE

    Fisher, Robert J.; Yu Ma

    2014-01-01

    The research examines how the attractiveness of children in need affects the empathy they evoke and the subsequent help they receive from unrelated adults. The authors find that attractive children are attributed desirable characteristics related to social competence, which is consistent with the "beautiful is good" stereotype. Ironically, the authors find that these attributions reduce the empathy evoked by attractive children and the help they receive from unrelated adults as long as their ...

  10. Host switching in a generalist parasitoid: contrasting transient and transgenerational costs associated with novel and original host species.

    Science.gov (United States)

    Jones, Thomas S; Bilton, Adam R; Mak, Lorraine; Sait, Steven M

    2015-01-01

    Parasitoids face challenges by switching between host species that influence survival and fitness, determine their role in structuring communities, influence species invasions, and affect their importance as biocontrol agents. In the generalist parasitoid, Venturia canescens (Gravenhorst) (Hymenoptera: Ichneumonidae), we investigated the costs in encapsulation, survival, and body size on juveniles when adult parasitoids switched from their original host, Plodia interpunctella (Hübner) (Lepidotera, Pyralidae) to a novel host, Ephestia kuehniella (Zeller) (Lepidoptera, Pyralidae), over multiple generations. Switching had an initial survival cost for juvenile parasitoids in the novel host, but increased survival occurred within two generations. Conversely, mortality in the original host increased. Body size, a proxy for fecundity, also increased with the number of generations in the novel host species, reflecting adaptation or maternal effects due to the larger size of the novel host, and therefore greater resources available to the developing parasitoid. Switching to a novel host appears to have initial costs for a parasitoid, even when the novel host may be better quality, but the costs rapidly diminish. We predict that the net cost of switching to a novel host for parasitoids will be complex and will depend on the initial reduction in fitness from parasitizing a novel host versus local adaptations against parasitoids in the original host. PMID:25691971

  11. New parasitoid-predator associations: female parasitoids do not avoid competition with generalist predators when sharing invasive prey

    Science.gov (United States)

    Chailleux, Anaïs; Wajnberg, Eric; Zhou, Yuxiang; Amiens-Desneux, Edwige; Desneux, Nicolas

    2014-12-01

    Optimal habitat selection is essential for species survival in ecosystems, and interspecific competition is a key ecological mechanism for many observed species association patterns. Specialized animal species are commonly affected by resource and interference competition with generalist and/or omnivorous competitors, so avoidance behavior could be expected. We hypothesize that specialist species may exploit broad range cues from such potential resource competitors (i.e., cues possibly common to various generalist and/or omnivorous predators) to avoid costly competition regarding food or reproduction, even in new species associations. We tested this hypothesis by studying short-term interactions between a native larval parasitoid and a native generalist omnivorous predator recently sharing the same invasive host/prey, the leaf miner Tuta absoluta. We observed a strong negative effect of kleptoparasitism (food resource stealing) instead of classical intraguild predation on immature parasitoids. There was no evidence that parasitoid females avoided the omnivorous predator when searching for oviposition sites, although we studied both long- and short-range known detection mechanisms. Therefore, we conclude that broad range cue avoidance may not exist in our biological system, probably because it would lead to too much oviposition site avoidance which would not be an efficient and, thus, beneficial strategy. If confirmed in other parasitoids or specialist predators, our findings may have implications for population dynamics, especially in the current context of increasing invasive species and the resulting creation of many new species associations.

  12. Host-Size Mediated Trade-Off in a Parasitoid Sclerodermus harmandi

    OpenAIRE

    Liu, Zhudong; Xu, Bingbing; Li LI; Sun, Jianghua

    2011-01-01

    Optimality models of host-parasitoid relationships have traditionally assumed that host quality increases as a function of host size at parasitism. However, trade-offs may play a crucial role in species evolution and should be found in host-parasitoid interactions where the host quality may differ between different sizes. Here, we investigated the effects of host size differences of Monochamus alternatus larva on foraging decisions, parasitism and related fitness in a gregarious ectoparasitoi...

  13. The Effect of Physical Attractiveness and Spokesperson Sex on Perceived Source and Organization Credibility.

    Science.gov (United States)

    Robinson, Donna L.; And Others

    To explore the dimensions of credibility and physical attractiveness in a public relations setting, the impact of public relations (PR) spokesperson physical attractiveness--as operationalized as photographs of the spokesperson attached to a press release--on perceptions of both the writer's and the organization's credibility was examined.…

  14. Effects of attractiveness and social status on dating desire in heterosexual adolescents: An experimental study

    NARCIS (Netherlands)

    Ha, P.T.; Overbeek, G.J.; Engels, R.C.M.E.

    2010-01-01

    The present study examined to what extent adolescent dating desire is based on attractiveness and social status of a potential short-term partner. Further, we tested whether self-perceived mate value moderated the relationship between dating desire and attractiveness of a potential partner. Data wer

  15. The Effects of Relaxation and Cognitive Expectancy on Attraction in a Social Interaction.

    Science.gov (United States)

    Wilson, Midge

    One approach to searching for determinants of interpersonal attraction involves the altering and studying of physiological arousal, psychological stress, and moods. On the basis of the reinforcement-affect model of attraction, it was hypothesized that the positive feelings obtained from undergoing relaxation exercises could serve to enhance…

  16. The Effects of Similarity, Evaluation, and Self-Esteem on Interpersonal Attraction.

    Science.gov (United States)

    Sachs, Donald H.

    It was predicted that high self-esteem subjects would have higher attraction scores than low self-esteem subjects to similar strangers or to strangers who gave positive personal evaluations. It was also predicted that high self-esteem subjects would have lower attraction scores than low self-esteem subjects to dissimilar strangers or to subjects…

  17. The Effects of Applicant Attractiveness, Managerial Attributes and Gender on Executive Employment Decisions.

    Science.gov (United States)

    Best, Bethia J.; Spector, Paul E.

    Although it has been shown that physical attractiveness is an advantage to male applicants for managerial positions, it is not clear whether attractiveness is an advantage or disadvantage to female applicants for these jobs. Male (N=25) and female (N=22) business administration students were asked to simulate selection decisions for a high level…

  18. Effect of Leg-to-Body Ratio on Body Shape Attractiveness.

    Science.gov (United States)

    Kiire, Satoru

    2016-05-01

    Recent studies have examined various aspects of human physical attractiveness. Attractiveness is considered an evolved psychological mechanism acquired via natural selection because an attractive body reflects an individual's health and fertility. The length of the legs is an often-emphasized aspect of attractiveness and has been investigated using the leg-to-body ratio (LBR), which reflects nutritional status of the infant, health status, fecundity, and other factors that are predictive of physical fitness. However, previous studies of leg length and physical fitness have produced mixed results. The present study investigated the relationship between LBR, defined as the height to perineum divided by total height, and perceived attractiveness. Three-dimensional stimuli (11 male and 11 female) were constructed with various LBR features. Each stimulus was rated by 40 women and 40 men in Japan on a 7-point scale. The results showed that the values closest to the average LBRs were rated as the most attractive. Furthermore, by fitting a quadratic curve on the relationship between attractiveness and LBR, an inverted U-shaped curve with the peak located at the average LBR was observed. In addition, high LBR values were rated as more attractive in females, whereas the opposite was true for males. These results suggest that average LBR is indicative of good health and good reproductive potential, whereas more extreme values are avoided because they could be indicative of diseases and other maladaptive conditions. PMID:26474977

  19. Gazing Behavior During Mixed-Sex Interactions: Sex and Attractiveness Effects

    NARCIS (Netherlands)

    Straaten, I. van; Holland, R.W.; Finkenauer, C.; Hollenstein, T.; Engels, R.C.M.E.

    2010-01-01

    We investigated to what extent the length of people's gazes during conversations with opposite-sex persons is affected by the physical attractiveness of the partner. Single participants (N = 115) conversed for 5 min with confederates who were rated either as low or high on physical attractiveness. F

  20. Effects of Profane Language and Physical Attractiveness on Perceptions of Counselor Behavior.

    Science.gov (United States)

    Paradise, Louis V.; And Others

    1980-01-01

    Data revealed that counselors using profanity were rated less favorably across all measures regardless of physical attractiveness. When profanity was present, female counselors were rated more positively than male counselors. Overall, physically attractive counselors were judged to have more favorable attributes. (Author)

  1. Functional response, host stage preference and interference of two whitefly parasitoids.

    Science.gov (United States)

    Xu, Hai-Yun; Yang, Nian-Wan; Duan, Min; Wan, Fang-Hao

    2016-02-01

    The functional responses of two parasitoids, Eretmocerus hayati Zolnerowich & Rose and Encarsia sophia Girault & Dodd, of whitefly Bemisia tabaci Gennadius Middle East-Asia Minor 1 were studied under laboratory conditions. In addition, the influence of host density and host stage on the competitive interactions between the two parasitoids, and biological control effect on whitefly were evaluated. In the functional response study, adult parasitoids were tested individually, with a conspecific or heterospecific competitor. Both Er. hayati and En. sophia exhibited a type II response to increasing host density, whether a conspecific or heterospecific competitor was present or not. Difference of searching rates and handling times between treatments suggested interference interactions existed between two parasitoid species. In the host stage preference study, two parasitoid species were jointly tested. Er. hayati had a competitive advantage over En. sophia when provided young host instars (first and second instar), whereas no advantage was found on old host instars (third and fourth instar). The biological control effect of Er. hayati and En. sophia in different introductions varied with host density. However, the effect of host instar on host mortality was not significant. These findings provide information for the practice of biological control and give better insight into how parasitoid species may coexist in diverse environments. PMID:25393924

  2. Natural enemies of three mealybug species (Hemiptera: Pseudococcidae) found on citrus and effects of some insecticides on the mealybug parasitoid Coccidoxenoides peregrinus (Hymenoptera: Encyrtidae) in South Africa.

    Science.gov (United States)

    Wakgari, W M; Giliomee, J H

    2003-06-01

    The population density of mealybug species in some South African citrus orchards has increased to pest status in recent years. The characterization of the natural enemy complex and quantification of their contribution to the control of Planococcus citri (Risso), Pseudococcus longispinus (Targioni-Tozzetti) and Pseudococcus calceolariae (Maskell) on Citrus limon (L.) and Citrus reticulata (Blanco) was investigated through intensive sampling. Eight primary and four secondary parasitoids, and two predator species were identified from P. citri and P. calceolariae. Anagyrus pseudococci (Girault) and Coccidoxenoides peregrinus (Timberlake) were the most common species, accounting for 44% and 21% of the total. Of the five primary parasitoids reared from P. longispinus, A. pseudococci and Anagyrus sp. were predominant, comprising 41% and 30%. Nymphal and adult parasitism (range = 0-26% vs. 0-66%) and predation (range = 0-5.6% vs. 0-4.1%) varied significantly between host trees and mealybug species (P triflumuron did not cause significant parasitoid mortality (P > 0.05). However, a mixture of pyriproxyfen and mineral oil caused a marginally significant mortality (P < 0.05). PMID:12762866

  3. Effects of Different Diets on the Dietary Attractability and Selectivity of Chinese Shrimp, Fenneropenaeus chinensis

    Institute of Scientific and Technical Information of China (English)

    HUANG Guoqiang; DONG Shuanglin; WANG Fang

    2005-01-01

    Attractabilities of different diets and dietary selectivity of Chinese shrimp, Fenneropenaeus chinensis were studied through behavior observation and feeding experiment, respectively. The five diets used in the experiment are: Fish Flesh (FF), Shrimp Flesh (SF), Clam Foot (CF), Polychaete Worm (PW), and Formulated Diet (FD). No significant differences of attractability exist between any two different diets when every two natural diets or all five diets are provided simultaneously. On the other hand, significant differences of attractability existbetween FD and every single natural diet when they are provided simultaneously. Results of behavioral observation indicate that natural diets are more attractive than FD.In feeding experiment, Chineseshrimp has distinct selectivity on different diets. It positively selects CF and PW, negatively selects FF and SF, and excludes FD absolutely. The results of the present studies indicate that the dietary selectivity of shrimp was based not only on the attractabilities of the diets, but also on the responses such as growth and food conversion.

  4. Effects of different diets on the dietary attractability and selectivity of Chinese shrimp, Fenneropenaeus chinensis

    Science.gov (United States)

    Huang, Guoqiang; Dong, Shuanglin; Wang, Fang

    2005-01-01

    Attractabilities of different diets and dietary selectivity of Chinese shrimp, Fenneropenaeus chinensis were studied through behavior observation and feeding experiment, respectively. The five diets used in the experiment are: Fish Flesh (FF), Shrimp Flesh (SF), Clam Foot (CF), Polychaete Worm (PW), and Formulated Diet (FD). No significant differences of attractability exist between any two different diets when every two natural diets or all five diets are provided simultaneously. On the other hand, significant differences of attractability exist between FD and every single natural diet when they are provided simultaneously. Results of behavioral observation indicate that natural diets are more attractive than FD. In feeding experiment, Chinese shrimp has distinct selectivity on different diets. It positively selects CF and PW, negatively selects FF and SF, and excludes FD absolutely. The results of the present studies indicate that the dietary selectivity of shrimp was based not only on the attractabilities of the diets, but also on the responses such as growth and food conversion.

  5. Trade-Off Between Fitness Gain and Cost Determines Profitability of a Peach Aphid Parasitoid.

    Science.gov (United States)

    Khatri, Diwas; He, Xiong Z; Wang, Qiao

    2016-08-01

    Aphidius colemani (Viereck) (Hymenoptera: Aphidiidae) is commercially produced and utilized for biological control of peach aphid Myzus persicae (Sulzer) (Hemiptera: Aphididae) on greenhouse crops in many countries. To provide knowledge for the evaluation of parasitoid-host interactions and development of effective mass rearing programs, we investigated how and why host age or size affected fitness gain in A. colemani We show that the parasitoid was significantly more likely to encounter larger hosts and that an encounter almost always triggered an attack attempt. However, the attack attempt did not proportionally translate into oviposition because larger aphids had greater ability to defend themselves and the parasitoid spent more time in handling larger aphids. The host age at parasitization had no effect on emergence rates and sex ratio of parasitoid progeny, suggesting that pupae and larvae have similar survival rate in hosts of different ages and/or the parasitoid females do not adjust sex allocation based on host size. When parasitizing mid-aged hosts, the parasitoid gained maximum fitness for their progeny in developmental period, body size, and parasitism. Taking all findings together, we suggest that parasitizing mid-aged green peach aphid nymphs is most profitable for A. colemani. PMID:27289084

  6. Interactions between pupae of the pine processionary moth (Thaumetopoea pityocampa) and parasitoids in a Pinus forest.

    Science.gov (United States)

    Bonsignore, C P; Manti, F; Castiglione, E

    2015-10-01

    Parasitoids are significant enemies of many economically important insects and there is some evidence to suggest that their actions have a role in terminating the outbreaks of forest Lepidoptera populations. In this study, we examined the impact of parasitoids on the pupae of the pine processionary moth, and highlighted the presence of several parasitoid species for this developmental stage. A higher rate of parasitism was found when the pupal density in the soil was reduced, but the rate of parasitism was not influenced by pupal morphological traits or by the presence or absence of a cocoon around a pupa. Of the external factors examined, a delay in the time of descent of larvae from the trees had a positive effect on the level of parasitism. Observational data indicated that dipteran and hymenopteran were the most abundant parasitoids to emerge from moth pupae. Our study highlights the complexity of the parasitoid-host dynamics, and stresses the importance of carefully determining environmental effects on host-parasitoid relations. PMID:26104534

  7. Indirect plant-parasitoid interactions mediated by changes in herbivore physiology.

    Science.gov (United States)

    Kaplan, Ian; Carrillo, Juli; Garvey, Michael; Ode, Paul J

    2016-04-01

    In occupying an intermediate trophic position, herbivorous insects serve a vital link between plants at the base of the food chain and parasitoids at the top. Although these herbivore-mediated indirect plant-parasitoid interactions are well-documented, new studies have uncovered previously undescribed mechanisms that are fundamentally changing how we view tri-trophic relationships. In this review we highlight recent advances in this field focusing on both plant-driven and parasitoid-driven outcomes that flow up and down the trophic web, respectively. From the bottom-up, plant metabolites can impact parasitoid success by altering host immune function; however, few have considered the potential effects of other plant defense strategies such as tolerance on parasitoid ecology and behavior. From the top-down, parasitoids have long been considered plant bodyguards, but in reality the consequences of parasitism for herbivory rates and induction of plant defensive chemistry are far more complicated with cascading effects on community-level interactions. PMID:27436656

  8. Effect of manipulated prestige-car ownership on both sex attractiveness ratings.

    Science.gov (United States)

    Dunn, Michael J; Searle, Robert

    2010-02-01

    Previous studies have shown that male attractiveness can be enhanced by manipulation of status through, for example, the medium of costume. The present study experimentally manipulated status by seating the same target model (male and female matched for attractiveness) expressing identical facial expressions and posture in either a 'high status' (Silver Bentley Continental GT) or a 'neutral status' (Red Ford Fiesta ST) motor-car. A between-subjects design was used whereby the above photographic images were presented to male and female participants for attractiveness rating. Results showed that the male target model was rated as significantly more attractive on a rating scale of 1-10 when presented to female participants in the high compared to the neutral status context. Males were not influenced by status manipulation, as there was no significant difference between attractiveness ratings for the female seated in the high compared to the neutral condition. It would appear that despite a noticeable increase in female ownership of prestige/luxury cars over recent years males, unlike females remain oblivious to such cues in matters pertaining to opposite-sex attraction. These findings support the results of previous status enhancement of attractiveness studies especially those espousing sex differences in mate preferences are due to sex-specific adaptations. PMID:19302732

  9. Post-release dispersal in animal translocations: social attraction and the "vacuum effect".

    Science.gov (United States)

    Mihoub, Jean-Baptiste; Robert, Alexandre; Le Gouar, Pascaline; Sarrazin, François

    2011-01-01

    Animal translocations are human-induced colonizations that can represent opportunities to contribute to the knowledge on the behavioral and demographic processes involved in the establishment of animal populations. Habitat selection behaviors, such as social cueing, have strong implications on dispersal and affect the establishment success of translocations. Using modeling simulations with a two-population network model (a translocated population and a remnant population), we investigated the consequences of four habitat selection strategies on post-translocation establishment probabilities in short- and long-lived species. Two dispersal strategies using social cues (conspecific attraction and habitat copying) were compared to random and quality-based strategies. We measured the sensitivity of local extinctions to dispersal strategies, life cycles, release frequencies, remnant population and release group sizes, the proportion of breeders and the connectivity between populations. Our results indicate that social behaviors can compromise establishment as a result of post-release dispersal, particularly in long-lived species. This behavioral mechanism, the "vacuum effect", arises from increased emigration in populations that are small relative to neighboring populations, reducing their rate of population growth. The vacuum effect can drive small remnant populations to extinction when a translocated group is large. In addition, the magnitude of the vacuum effect varies non-linearly with connectivity. The vacuum effect represents a novel form of the behaviorally mediated Allee effect that can cause unexpected establishment failures or population extinctions in response to social cueing. Accounting for establishment probabilities as a conditional step to the persistence of populations would improve the accuracy of predicting the fates of translocated or natural (meta)populations. PMID:22194784

  10. Post-release dispersal in animal translocations: social attraction and the "vacuum effect".

    Directory of Open Access Journals (Sweden)

    Jean-Baptiste Mihoub

    Full Text Available Animal translocations are human-induced colonizations that can represent opportunities to contribute to the knowledge on the behavioral and demographic processes involved in the establishment of animal populations. Habitat selection behaviors, such as social cueing, have strong implications on dispersal and affect the establishment success of translocations. Using modeling simulations with a two-population network model (a translocated population and a remnant population, we investigated the consequences of four habitat selection strategies on post-translocation establishment probabilities in short- and long-lived species. Two dispersal strategies using social cues (conspecific attraction and habitat copying were compared to random and quality-based strategies. We measured the sensitivity of local extinctions to dispersal strategies, life cycles, release frequencies, remnant population and release group sizes, the proportion of breeders and the connectivity between populations. Our results indicate that social behaviors can compromise establishment as a result of post-release dispersal, particularly in long-lived species. This behavioral mechanism, the "vacuum effect", arises from increased emigration in populations that are small relative to neighboring populations, reducing their rate of population growth. The vacuum effect can drive small remnant populations to extinction when a translocated group is large. In addition, the magnitude of the vacuum effect varies non-linearly with connectivity. The vacuum effect represents a novel form of the behaviorally mediated Allee effect that can cause unexpected establishment failures or population extinctions in response to social cueing. Accounting for establishment probabilities as a conditional step to the persistence of populations would improve the accuracy of predicting the fates of translocated or natural (metapopulations.

  11. Eigenvalue Attraction

    Science.gov (United States)

    Movassagh, Ramis

    2016-02-01

    We prove that the complex conjugate (c.c.) eigenvalues of a smoothly varying real matrix attract (Eq. 15). We offer a dynamical perspective on the motion and interaction of the eigenvalues in the complex plane, derive their governing equations and discuss applications. C.c. pairs closest to the real axis, or those that are ill-conditioned, attract most strongly and can collide to become exactly real. As an application we consider random perturbations of a fixed matrix M. If M is Normal, the total expected force on any eigenvalue is shown to be only the attraction of its c.c. (Eq. 24) and when M is circulant the strength of interaction can be related to the power spectrum of white noise. We extend this by calculating the expected force (Eq. 41) for real stochastic processes with zero-mean and independent intervals. To quantify the dominance of the c.c. attraction, we calculate the variance of other forces. We apply the results to the Hatano-Nelson model and provide other numerical illustrations. It is our hope that the simple dynamical perspective herein might help better understanding of the aggregation and low density of the eigenvalues of real random matrices on and near the real line respectively. In the appendix we provide a Matlab code for plotting the trajectories of the eigenvalues.

  12. Fitness costs of intrinsic competition in two egg parasitoids of a true bug.

    Science.gov (United States)

    Cusumano, Antonino; Peri, Ezio; Boivin, Guy; Colazza, Stefano

    2015-10-01

    Intrinsic competition in insect parasitoids occurs when supernumerary larvae develop in the same host as consequence of multiple ovipositions by females of the same species (intra-specific competition) or by females of different species (inter-specific competition). Studies on intrinsic competition have mainly focused on understanding the factors that play a role in the outcome of competition, while fitness-related effects for the parasitoid surviving the competition have been poorly investigated, especially in egg parasitoids. Interestingly, even the winning parasitoid can experience fitness costs due to larval development in a host in which multiple factors have been injected by the ovipositing females or released by their larvae. In this paper we studied fitness-related traits associated with intra- and inter-specific competition between Trissolcus basalis (Wollaston) and Ooencyrtus telenomicida (Vassiliev), the main egg parasitoids associated with the southern green stink bug Nezara viridula (L.) in Italy. We investigated the impact of intrinsic competition for the surviving parasitoid in terms of body size, developmental time, number and size of oocytes. Our results indicated that T. basalis adults did not experience fitness-related costs when surviving intra-specific competition; however, adults were smaller, took longer to develop and females produced fewer oocytes after surviving inter-specific competition. A different outcome was found for O. telenomicida where the emerging females were smaller, produced fewer and smaller oocytes when suffering intra-specific competition whereas no fitness costs were found when adults survived inter-specific competition. These results support the hypothesis that the impact of intrinsic competition in egg parasitoids depends on the severity of the competitive interaction, as fitness costs were more pronounced when the surviving parasitoid interacted with the most detrimental competitor. PMID:26149765

  13. Regional tritrophic relationship patterns of five aphid parasitoid species (Hymenoptera: Braconidae: Aphidiinae) in agroecosystem-dominated landscapes of southeastern Europe.

    Science.gov (United States)

    Tomanović, Zeljko; Kavallieratos, Nickolas G; Starý, Petr; Stanisavljević, Ljubisa Z; Cetković, Aleksandar; Stamenković, Srdjan; Jovanović, Slobodan; Athanassiou, Christos G

    2009-06-01

    A regional survey of the complex tritrophic associations (parasitoid-aphid-plant) of aphid parasitoids (Hymenoptera: Braconidae: Aphidiinae) was carried out to determine and explore the patterns of those associations in various types of environments. Here, we present trophic relationship patterns of the five aphid parasitoid species in crop and noncrop habitats in southeastern Europe, and we contrast them in a regional (Mediterranean [MED] versus continental [CNT]) context. In total, 79 aphid host taxa were identified in this survey. Forty-two of these were recorded from noncrop plants only, 21 from crop plants only, and 18 were present on both types of plants. This means that approximately 74% of all the parasitoid-aphid trophic interactions that support the persistence of the five selected parasitoids are entirely (54%) or partially (20%) associated with noncrop plants. The correspondence of parasitoid-aphid combinations among habitat/region combinations is very high and specific. Our results suggest that Mediterranean and continental regions are clearly distinguished by a contrasting pattern of trophic interactions in crop habitats, whereas the noncrop habitats contribute in lesser degree to these differences. For the crop/noncrop breakdown, the number of nonspecific interactions was larger than expected in crop habitats, whereas in noncrop habitats the abundance of partially specific and specific interactions was larger. The analysis of variance for the regional and habitat distribution of mean aphid host number per parasitoid was highly significant. When both regions were analyzed separately, the parasitoid/crop design showed significant parasitoid effects as well as interactions, whereas the habitat effect was not significant for the Mediterranean region and highly so for the continental region. This highly complex pattern suggests that the mean number of parasitized aphid species is not distributed among parasitoids, regions, and habitats in a similar manner

  14. Competitive Interactions between Parasitoids Provide New Insight into Host Suppression

    OpenAIRE

    Xu, Hai-Yun; Yang, Nian-Wan; Wan, Fang-Hao

    2013-01-01

    Understanding the dynamics of potential inter- and intraspecific competition in parasitoid communities is crucial in the screening of efficient parasitoid species and for utilization of the best parasitoid species combinations. In this respect, the host-parasitoid systems, Bemisia tabaci and two parasitoids, Eretmocerus hayati (exotic) and Encarsia sophia (existing) were studied under laboratory conditions to investigate whether interference competition between the exotic and existing species...

  15. Host habitat assessment by a parasitoid using fungal volatiles

    Directory of Open Access Journals (Sweden)

    Steidle Johannes LM

    2007-02-01

    Full Text Available Abstract Background The preference – performance hypothesis predicts that oviposition preference of insects should correlate with host suitability for offspring development. Therefore, insect females have to be able to assess not only the quality of a given host but also the environmental conditions of the respective host habitat. Chemical cues are a major source of information used by insects for this purpose. Primary infestation of stored grain by stored product pests often favors the intense growth of mold. This can lead to distinct sites of extreme environmental conditions (hot-spots with increased insect mortality. We studied the influence of mold on chemical orientation, host recognition, and fitness of Lariophagus distinguendus, a parasitoid of beetle larvae developing in stored grain. Results Volatiles of wheat infested by Aspergillus sydowii and A. versicolor repelled female parasitoids in an olfactometer. Foraging L. distinguendus females are known to be strongly attracted to the odor of larval host feces from the granary weevil Sitophilus granarius, which may adhere in remarkable amounts to the surface of the grains. Feces from moldy weevil cultures elicited neutral responses but parasitoids clearly avoided moldy feces when non-moldy feces were offered simultaneously. The common fungal volatile 1-octen-3-ol was the major component of the odor of larval feces from moldy weevil cultures and repelled female parasitoids at naturally occurring doses. In bioassays investigating host recognition behavior of L. distinguendus, females spent less time on grains containing hosts from moldy weevil cultures and showed less drumming and drilling behavior than on non-moldy controls. L. distinguendus had a clearly reduced fitness on hosts from moldy weevil cultures. Conclusion We conclude that L. distinguendus females use 1-octen-3-ol for host habitat assessment to avoid negative fitness consequences due to secondary mold infestation of host

  16. Effects of attractive versus repulsive vibrotactile instructional cues during motion replication tasks.

    Science.gov (United States)

    Lee, Beom-Chan; Sienko, Kathleen H

    2011-01-01

    The Mobile Instrument for Motion Instruction and Correction (MIMIC) enables an expert (i.e., physical therapist) to map his/her movements to a trainee (i.e., patient) in a hands-free fashion. MIMIC comprises an Expert Module (EM) and a Trainee Module (TM); both modules include six-degree-of-freedom inertial measurement units, microcontrollers, and batteries. The TM also includes actuators that provide the trainee with vibrotactile instructional cues. The estimated expert body motion information is transmitted wirelessly to the trainee; based on the computed difference between the motions of the expert and trainee, directional instructions are displayed to the trainee's skin via vibrotactile stimulation. This study examined anterior-posterior trunk movements using a simplified version of the MIMIC system in which only two actuators were used to provide feedback and pre-recorded target trajectories were used to represent ideal expert movements. The study was designed to investigate the effects of attractive versus repulsive vibrotactile instructional cues when the motion speed and task complexity were varied. Preliminary results (n = 12) suggest that repulsive vibrotactile instructional cues lead to the greatest correlation between expert and subject motion, the least time delay, and the least tilt error. PMID:22255102

  17. Sexual Conflict and Gender Gap Effects: Associations between Social Context and Sex on Rated Attractiveness and Economic Status

    Science.gov (United States)

    Dixson, Barnaby J.

    2016-01-01

    Human mate choice research often concerns sex differences in the importance of traits such as physical attractiveness and social status. A growing number of studies indicate that cues to social context, including other people who appear in stimulus photographs, can alter that individual’s attractiveness. Fewer studies, however, consider judgements of traits other than physical attractiveness, such as wealth. Here we manipulate the presence/absence of other people in photographs of target models, and test the effects on judgments of both attractiveness and earnings (a proxy for status). Participants (N = 2044) rated either male or female models for either physical attractiveness or social/economic status when presented alone, with same sex others or with opposite sex others. We collectively refer to this manipulation as ‘social context’. Male and female models received similar responses for physical attractiveness, but social context affected ratings of status differently for women and men. Males presented alongside other men received the highest status ratings while females presented alone were given the highest status ratings. Further, the status of females presented alongside a male was constrained by the rated status of that male. Our results suggests that high status may not directly lead to high attractiveness in men, but that status is more readily attributed to men than to women. This divide in status between the sexes is very clear when men and women are presented together, possibly reflecting one underlying mechanism of the modern day gender gap and sexist attitudes to women’s economic participation. This adds complexity to our understanding of the relationship between attractiveness, status, and sex in the light of parental investment theory, sexual conflict and economic theory. PMID:26731414

  18. Sexual Conflict and Gender Gap Effects: Associations between Social Context and Sex on Rated Attractiveness and Economic Status.

    Science.gov (United States)

    Gouda-Vossos, Amany; Dixson, Barnaby J; Brooks, Robert C

    2016-01-01

    Human mate choice research often concerns sex differences in the importance of traits such as physical attractiveness and social status. A growing number of studies indicate that cues to social context, including other people who appear in stimulus photographs, can alter that individual's attractiveness. Fewer studies, however, consider judgements of traits other than physical attractiveness, such as wealth. Here we manipulate the presence/absence of other people in photographs of target models, and test the effects on judgments of both attractiveness and earnings (a proxy for status). Participants (N = 2044) rated either male or female models for either physical attractiveness or social/economic status when presented alone, with same sex others or with opposite sex others. We collectively refer to this manipulation as 'social context'. Male and female models received similar responses for physical attractiveness, but social context affected ratings of status differently for women and men. Males presented alongside other men received the highest status ratings while females presented alone were given the highest status ratings. Further, the status of females presented alongside a male was constrained by the rated status of that male. Our results suggests that high status may not directly lead to high attractiveness in men, but that status is more readily attributed to men than to women. This divide in status between the sexes is very clear when men and women are presented together, possibly reflecting one underlying mechanism of the modern day gender gap and sexist attitudes to women's economic participation. This adds complexity to our understanding of the relationship between attractiveness, status, and sex in the light of parental investment theory, sexual conflict and economic theory. PMID:26731414

  19. Sexual Conflict and Gender Gap Effects: Associations between Social Context and Sex on Rated Attractiveness and Economic Status.

    Directory of Open Access Journals (Sweden)

    Amany Gouda-Vossos

    Full Text Available Human mate choice research often concerns sex differences in the importance of traits such as physical attractiveness and social status. A growing number of studies indicate that cues to social context, including other people who appear in stimulus photographs, can alter that individual's attractiveness. Fewer studies, however, consider judgements of traits other than physical attractiveness, such as wealth. Here we manipulate the presence/absence of other people in photographs of target models, and test the effects on judgments of both attractiveness and earnings (a proxy for status. Participants (N = 2044 rated either male or female models for either physical attractiveness or social/economic status when presented alone, with same sex others or with opposite sex others. We collectively refer to this manipulation as 'social context'. Male and female models received similar responses for physical attractiveness, but social context affected ratings of status differently for women and men. Males presented alongside other men received the highest status ratings while females presented alone were given the highest status ratings. Further, the status of females presented alongside a male was constrained by the rated status of that male. Our results suggests that high status may not directly lead to high attractiveness in men, but that status is more readily attributed to men than to women. This divide in status between the sexes is very clear when men and women are presented together, possibly reflecting one underlying mechanism of the modern day gender gap and sexist attitudes to women's economic participation. This adds complexity to our understanding of the relationship between attractiveness, status, and sex in the light of parental investment theory, sexual conflict and economic theory.

  20. Fatal attraction

    DEFF Research Database (Denmark)

    Jensen, Kim Ebensgaard

    2012-01-01

    The purpose of this paper is two-fold. Firstly, it presents an argument for usage-based inheritance models over complete inheritance models in construction grammar. It is argued that, with the principle of inductive language learning as their foundation, usage-based inheritance models allow for...... redundancies and incongruities in construction networks which enables linguists to take into account details of language use, which would otherwise not be facilitated in complete inheritance models. Secondly, making use of the method of collostructional analysis, the article offers a corpus-based description...... of the use of the Danish ihjel-construction which accounts for patterns of attraction of construction-verb attraction, patterns of productivity, and various types of subconstructions, including item- and item-class-based ones and metaphorical extensions. The description of the ihjel...

  1. Effects of selected defoliants in combination with insecticides on sweetpotato whitefly (Hemiptera: Aleyrodidae) and its parasitoids in cotton

    Science.gov (United States)

    Effects of two defoliants, Def (S, S, Stributylphosphorotrithioate) and Dropp (thidiazuron) alone and in combination with two commonly used insecticides, a pyrethroid, Karate (lambda-cyhalothrin) and an organophosphate, Guthion (azinphosmethyl) on sweetpotato whitefly, Bemisia tabaci Gennadius Bioty...

  2. The Undermining Effect of Facial Attractiveness on Brain Responses to Fairness in Ultimatum Game: An ERP Study

    Directory of Open Access Journals (Sweden)

    Qingguo eMa

    2015-03-01

    Full Text Available To investigate the time course of the neural processing of facial attractiveness and its influence on fairness consideration during social interactions, event-related potentials (ERP were recorded from 21 male subjects performing a two-person Ultimatum Game (UG. During this bargaining game, the male subjects played responders who decided whether to accept offers from female proposers, whose facial images (grouped as attractive and unattractive were presented prior to the offer presentation. The behavioral data demonstrated that the acceptance ratio increased with the fairness level of the offers and, more importantly, the subjects were more likely to accept unfair offers when presented with the attractive-face condition compared with the unattractive-face condition. The reaction times (RTs for five offers (1:9, 2:8, 3:7, 4:6 and 5:5 in the unattractive-face condition were not significantly different. In contrast, the subjects reacted slower to the attractive proposers’ unfair offers and quicker to fair offers. The ERP analysis of the face presentation demonstrated a decreased early negativity (N2 and enhanced late positive potentials (LPPs elicited by the attractive faces compared with the unattractive faces. In addition, the feedback-related negativity (FRN in response to an offer presentation was not significantly different for the unfair (1:9 and 2:8 and fair (4:6 and 5:5 offers in the attractive-face condition. However, the unfair offers generated larger FRNs compared with the fair offers in the unattractive-face condition (consistent with prior studies. A similar effect was identified for P300. The present study demonstrated an undermining effect of proposer facial attractiveness on responder consideration of offer fairness during the UG.

  3. The undermining effect of facial attractiveness on brain responses to fairness in the Ultimatum Game: an ERP study.

    Science.gov (United States)

    Ma, Qingguo; Hu, Yue; Jiang, Shushu; Meng, Liang

    2015-01-01

    To investigate the time course of the neural processing of facial attractiveness and its influence on fairness consideration during social interactions, event-related potentials (ERP) were recorded from 21 male subjects performing a two-person Ultimatum Game (UG). During this bargaining game, the male subjects played responders who decided whether to accept offers from female proposers, whose facial images (grouped as "attractive" and "unattractive") were presented prior to the offer presentation. The behavioral data demonstrated that the acceptance ratio increased with the fairness level of the offers and, more importantly, the subjects were more likely to accept unfair offers when presented with the attractive-face condition compared with the unattractive-face condition. The reaction times (RTs) for five offers (1:9, 2:8, 3:7, 4:6, and 5:5) in the unattractive-face condition were not significantly different. In contrast, the subjects reacted slower to the attractive proposers' unfair offers and quicker to fair offers. The ERP analysis of the face presentation demonstrated a decreased early negativity (N2) and enhanced late positive potentials (LPPs) elicited by the attractive faces compared with the unattractive faces. In addition, the feedback-related negativity (FRN) in response to an offer presentation was not significantly different for the unfair (1:9 and 2:8) and fair (4:6 and 5:5) offers in the attractive-face condition. However, the unfair offers generated larger FRNs compared with the fair offers in the unattractive-face condition (consistent with prior studies). A similar effect was identified for P300. The present study demonstrated an undermining effect of proposer facial attractiveness on responder consideration of offer fairness during the UG. PMID:25805967

  4. Effects of root herbivory on pyrrolizidine alkaloid content and aboveground plant-herbivore-parasitoid interactions in Jacobaea vulgaris

    NARCIS (Netherlands)

    Kostenko, O.; Mulder, P.P.J.; Bezemer, T.M.

    2013-01-01

    The importance of root herbivory is increasingly recognized in ecological studies, and the effects of root herbivory on plant growth, chemistry, and performance of aboveground herbivores have been relatively well studied. However, how belowground herbivory by root feeding insects affects aboveground

  5. Effects of Root Herbivory on Pyrrolizidine Alkaloid Content and Aboveground Plant-Herbivore-Parasitoid Interactions in Jacobaea Vulgaris

    NARCIS (Netherlands)

    Kostenko, O.; Mulder, P.P.J.; Bezemer, T.M.

    2013-01-01

    The importance of root herbivory is increasingly recognized in ecological studies, and the effects of root herbivory on plant growth, chemistry, and performance of aboveground herbivores have been relatively well studied. However, how belowground herbivory by root feeding insects affects aboveground

  6. Effects of gender and physical attractiveness on visual attention to Facebook profiles.

    Science.gov (United States)

    Seidman, Gwendolyn; Miller, Olivia S

    2013-01-01

    The current study examined viewers' gaze while observing Facebook profiles of strangers varying in gender and physical attractiveness. Fifty-one participants viewed four Facebook profiles, a physically attractive and unattractive individual of each gender. Participants' eye movements were tracked as they viewed each profile for 60 seconds. Results showed that participants paid more attention to the physical appearance (main profile photograph) of female than of male profile owners and to the personal information (likes and interests) of male than to female profile owners. Participants spent more time focusing on information that was irrelevant to forming an impression of the profile owner (advertisements) when viewing the profiles of unattractive than attractive individuals, suggesting that they made a greater effort to learn about these individuals. PMID:23153080

  7. Effects of religious veiling on Muslim men's attractiveness ratings of Muslim women.

    Science.gov (United States)

    Pazhoohi, Farid; Hosseinchari, Masoud

    2014-08-01

    Hijab and other Islamic veiling clothing are important social and political symbols for Muslim women's identity. Although recently there has been a large body of literature on the social and political aspects of hijab in Western countries, there has been no investigation of the origin and function of veiling itself. This article hypothesized that religious veiling, which eliminates the estrogen-induced body curves of reproductive age women, decreases men's perceptions of women's physical attractiveness, thereby serving mate guarding functions against rival men. To test this hypothesis. Measures of the motivational appeal and self-reported perceived attractiveness of women exhibiting different degrees of veiling were obtained from 80 Muslim male participants. The results showed that men were more motivated to view women exhibiting the less veiling and rated them more attractive than those women whose bodily curves were less apparent. These results support veiling serving a mate guarding function and reinforcing the marital bond. PMID:24464549

  8. Artificial nighttime light changes aphid-parasitoid population dynamics.

    Science.gov (United States)

    Sanders, Dirk; Kehoe, Rachel; Tiley, Katie; Bennie, Jonathan; Cruse, Dave; Davies, Thomas W; Frank van Veen, F J; Gaston, Kevin J

    2015-01-01

    Artificial light at night (ALAN) is recognized as a widespread and increasingly important anthropogenic environmental pressure on wild species and their interactions. Understanding of how these impacts translate into changes in population dynamics of communities with multiple trophic levels is, however, severely lacking. In an outdoor mesocosm experiment we tested the effect of ALAN on the population dynamics of a plant-aphid-parasitoid community with one plant species, three aphid species and their specialist parasitoids. The light treatment reduced the abundance of two aphid species by 20% over five generations, most likely as a consequence of bottom-up effects, with reductions in bean plant biomass being observed. For the aphid Megoura viciae this effect was reversed under autumn conditions with the light treatment promoting continuous reproduction through asexuals. All three parasitoid species were negatively affected by the light treatment, through reduced host numbers and we discuss induced possible behavioural changes. These results suggest that, in addition to direct impacts on species behaviour, the impacts of ALAN can cascade through food webs with potentially far reaching effects on the wider ecosystem. PMID:26472251

  9. Identification and evaluation of Trichogramma parasitoids for biological pest control

    OpenAIRE

    Silva, I.M.M.S.

    1999-01-01

    Egg parasitoids of the genus Trichogramma are used as biological control agents against lepidopterous pests. From the 180 species described world-wide, only 5 have large scale application. The development of better methods to select other Trichogramma species/strains is necessary for a more effective use of these wasps against target pests. The main aim of this thesis is to investigate criteria and methods for identification and selection of Trichogramma species/strains for biological control...

  10. Artificial nighttime light changes aphid-parasitoid population dynamics

    OpenAIRE

    Dirk Sanders; Rachel Kehoe; Katie Tiley; Jonathan Bennie; Dave Cruse; Davies, Thomas W; F J Frank van Veen; Gaston, Kevin J

    2015-01-01

    Artificial light at night (ALAN) is recognized as a widespread and increasingly important anthropogenic environmental pressure on wild species and their interactions. Understanding of how these impacts translate into changes in population dynamics of communities with multiple trophic levels is, however, severely lacking. In an outdoor mesocosm experiment we tested the effect of ALAN on the population dynamics of a plant-aphid-parasitoid community with one plant species, three aphid species an...

  11. Consequences of Beauty: Effects of Rater Sex and Sexual Orientation on the Visual Exploration and Evaluation of Attractiveness in Real World Scenes.

    Science.gov (United States)

    Mitrovic, Aleksandra; Tinio, Pablo P L; Leder, Helmut

    2016-01-01

    One of the key behavioral effects of attractiveness is increased visual attention to attractive people. This effect is often explained in terms of evolutionary adaptations, such as attractiveness being an indicator of good health. Other factors could influence this effect. In the present study, we explored the modulating role of sexual orientation on the effects of attractiveness on exploratory visual behavior. Heterosexual and homosexual men and women viewed natural-looking scenes that depicted either two women or two men who varied systematically in levels of attractiveness (based on a pre-study). Participants' eye movements and attractiveness ratings toward the faces of the depicted people were recorded. The results showed that although attractiveness had the largest influence on participants' behaviors, participants' sexual orientations strongly modulated the effects. With the exception of homosexual women, all participant groups looked longer and more often at attractive faces that corresponded with their sexual orientations. Interestingly, heterosexual and homosexual men and homosexual women looked longer and more often at the less attractive face of their non-preferred sex than the less attractive face of their preferred sex, evidence that less attractive faces of the preferred sex might have an aversive character. These findings provide evidence for the important role that sexual orientation plays in guiding visual exploratory behavior and evaluations of the attractiveness of others. PMID:27047365

  12. The Effect of Company Recruitment Web Site Orientation on Individuals' Perceptions of Organizational Attractiveness.

    Science.gov (United States)

    Williamson, Ian O.; Lepak, David P.; King, James

    2003-01-01

    To obtain information on job opportunities, business students (n=252) visited company websites having either a recruitment or selection orientation or both. Attractiveness of the organization was significantly higher for recruitment-oriented sites. Perceived usefulness and ease of use influenced outcome expectancy and organizational…

  13. Attracting the World: Institutional Initiatives' Effects on International Students' Decision to Enroll

    Science.gov (United States)

    Bohman, Eric

    2014-01-01

    Community colleges have increased their efforts to attract international students, but little is known how these active efforts influence international students' decisions to attend a community college. This longitudinal study focuses on international students at one community college that embarked on an active international student…

  14. Therapeugenic Factors in Psychotherapy: The Effect of Attitude Similarity on Therapist Credibility and Attraction.

    Science.gov (United States)

    Trautt, Gregory M.; And Others

    1980-01-01

    The therapist with similar attitudes was seen as more qualified, higher in interpersonal attraction, and more likeable. Subjects were more willing to recommend or seek therapy from these therapists. Significant interaction indicated that male subjects were more affected by the degree of attitude similarity. (Author)

  15. Effects of Sex, Attraction, and Acceptance on Children's Help Seeking and Attitudes to Interpersonal Relationships.

    Science.gov (United States)

    Downe, Alan G.; McDougall, Daniel

    1995-01-01

    A study involving 124 male and 128 female sixth graders found that sex differences existed in willingness to receive help and helper preferences, and that high-attraction subjects showed higher orientation toward including other children in their activities, accepting control from others, and being affectionate around others. (SLD)

  16. Separating the effects of repulsive and attractive forces on the phase diagram, interfacial, and critical properties of simple fluids.

    Science.gov (United States)

    Fuentes-Herrera, M; Moreno-Razo, J A; Guzmán, O; López-Lemus, J; Ibarra-Tandi, B

    2016-06-01

    Molecular simulations in the canonical and isothermal-isobaric ensembles were performed to study the effect of varying the shape of the intermolecular potential on the phase diagram, critical, and interfacial properties of model fluids. The molecular interactions were modeled by the Approximate Non-Conformal (ANC) theory potentials. Unlike the Lennard-Jones or Morse potentials, the ANC interactions incorporate parameters (called softnesses) that modulate the steepness of the potential in their repulsive and attractive parts independently. This feature allowed us to separate unambiguously the role of each region of the potential on setting the thermophysical properties. In particular, we found positive linear correlation between all critical coordinates and the attractive and repulsive softness, except for the critical density and the attractive softness which are negatively correlated. Moreover, we found that the physical properties related to phase coexistence (such as span of the liquid phase between the critical and triple points, variations in the P-T vaporization curve, interface width, and surface tension) are more sensitive to changes in the attractive softness than to the repulsive one. Understanding the different roles of attractive and repulsive forces on phase coexistence may contribute to developing more accurate models of liquids and their mixtures. PMID:27276958

  17. Separating the effects of repulsive and attractive forces on the phase diagram, interfacial, and critical properties of simple fluids

    Science.gov (United States)

    Fuentes-Herrera, M.; Moreno-Razo, J. A.; Guzmán, O.; López-Lemus, J.; Ibarra-Tandi, B.

    2016-06-01

    Molecular simulations in the canonical and isothermal-isobaric ensembles were performed to study the effect of varying the shape of the intermolecular potential on the phase diagram, critical, and interfacial properties of model fluids. The molecular interactions were modeled by the Approximate Non-Conformal (ANC) theory potentials. Unlike the Lennard-Jones or Morse potentials, the ANC interactions incorporate parameters (called softnesses) that modulate the steepness of the potential in their repulsive and attractive parts independently. This feature allowed us to separate unambiguously the role of each region of the potential on setting the thermophysical properties. In particular, we found positive linear correlation between all critical coordinates and the attractive and repulsive softness, except for the critical density and the attractive softness which are negatively correlated. Moreover, we found that the physical properties related to phase coexistence (such as span of the liquid phase between the critical and triple points, variations in the P-T vaporization curve, interface width, and surface tension) are more sensitive to changes in the attractive softness than to the repulsive one. Understanding the different roles of attractive and repulsive forces on phase coexistence may contribute to developing more accurate models of liquids and their mixtures.

  18. The potential attractant or repellent effects of different water types on oviposition in Aedes aegypti L. (Dipt., Culicidae)

    NARCIS (Netherlands)

    Navarro, D.M.A.F.; Oliveira, de P.E.S.; Potting, R.P.J.; Brito, A.C.; Fital, S.J.F.; Goulart Sant Ana, A.E.

    2003-01-01

    The selection of oviposition sites by the yellow-fever mosquito, Aedes aegypti , was studied in the laboratory. The repellent or attractant effects of salinity and the presence of bacteria in water collected from a local community on the Brazilian coast were investigated. Water contaminated with bac

  19. Job Attraction Predictors for Graduate Professional Students: The Effects of Job Attributes, Gender, and Year of Graduate Study.

    Science.gov (United States)

    Winter, Paul A.; Butters, Janice M.

    1999-01-01

    Examined the effects of job attributes and student characteristics on graduate professional students' job attraction using two theoretical models. Dental students evaluated content-validated descriptions of three professional job options. Results indicated that significant predictors were job attributes, job attributes-by-gender interactions, and…

  20. Influence of temperature on patch residence time in parasitoids: physiological and behavioural mechanisms

    Science.gov (United States)

    Moiroux, Joffrey; Abram, Paul K.; Louâpre, Philippe; Barrette, Maryse; Brodeur, Jacques; Boivin, Guy

    2016-04-01

    Patch time allocation has received much attention in the context of optimal foraging theory, including the effect of environmental variables. We investigated the direct role of temperature on patch time allocation by parasitoids through physiological and behavioural mechanisms and its indirect role via changes in sex allocation and behavioural defences of the hosts. We compared the influence of foraging temperature on patch residence time between an egg parasitoid, Trichogramma euproctidis, and an aphid parasitoid, Aphidius ervi. The latter attacks hosts that are able to actively defend themselves, and may thus indirectly influence patch time allocation of the parasitoid. Patch residence time decreased with an increase in temperature in both species. The increased activity levels with warming, as evidenced by the increase in walking speed, partially explained these variations, but other mechanisms were involved. In T. euproctidis, the ability to externally discriminate parasitised hosts decreased at low temperature, resulting in a longer patch residence time. Changes in sex allocation with temperature did not explain changes in patch time allocation in this species. For A. ervi, we observed that aphids frequently escaped at intermediate temperature and defended themselves aggressively at high temperature, but displayed few defence mechanisms at low temperature. These defensive behaviours resulted in a decreased patch residence time for the parasitoid and partly explained the fact that A. ervi remained for a shorter time at the intermediate and high temperatures than at the lowest temperature. Our results suggest that global warming may affect host-parasitoid interactions through complex mechanisms including both direct and indirect effects on parasitoid patch time allocation.

  1. Short- and long-range cues used by ground-dwelling parasitoids to find their host.

    Science.gov (United States)

    Goubert, C; Josso, C; Louâpre, P; Cortesero, A M; Poinsot, D

    2013-02-01

    Parasitoids of phytophagous insects face a detectability-reliability dilemma when foraging for hosts. Plant-related cues are easily detectable, but do not guarantee the presence of the host. Host-related cues are very reliable, but much harder to detect from a distance. Little is known in particular about the way coleopteran parasitoid females use these cues when foraging for a suitable place to lay their eggs. The question is of interest because, unlike hymenopteran larvae, coleopteran parasitoid larvae are highly mobile and able to forage for hosts on their own. We assessed whether females of the parasitoid rove beetle Aleochara bipustulata (L.) (Coleoptera: Staphylinidae) are attracted to plant (Swede roots, Brassica napus) and host-related cues [pupae of the cabbage root fly Delia radicum (L.) (Diptera: Anthomyiidae)]. In the field, A. bipustulata adult females were captured in selective pitfall traps containing pieces of roots damaged by D. radicum larvae, but not in traps containing pieces of healthy roots or D. radicum pupae. However, in the laboratory, the odour of D. radicum pupae attracted A. bipustulata females to mini-pitfalls. Video monitoring in the laboratory showed that foraging A. bipustulata females preferred a zone containing D. radicum pupae and larval tracks rather than one containing an extract of D. radicum-infested roots. Our results suggest a behavioural sequence where A. bipustulata females use plant-related cues at a distance, but then switch their preference to host-related cues at a close range. This would be the first observation of this behaviour in coleopteran parasitoids. PMID:23296403

  2. Attractiveness and Effectiveness of Competing Tourist Areas: A Study on Italian Provinces

    OpenAIRE

    2005-01-01

    Tourism has become a wide-spread phenomenon in our age and a focal point of economic policy of many regions competing for the favours of tourists. Consequently, competitiveness of tourist destinations has received increasing interest in economic research with a view to the identification of the user attractiveness of a tourist area. The present paper is inspired by the conceptual competitiveness model developed by Crouch and Ritchie and presents an attempt to assess the relative attractivenes...

  3. Boosting spin-caloritronic effects by attractive correlations in molecular junctions

    Science.gov (United States)

    Weymann, Ireneusz

    2016-01-01

    In nanoscopic systems quantum confinement and interference can lead to an enhancement of thermoelectric properties as compared to conventional bulk materials. For nanostructures, such as molecules or quantum dots coupled to external leads, the thermoelectric figure of merit can reach or even exceed unity. Moreover, in the presence of external magnetic field or when the leads are ferromagnetic, an applied temperature gradient can generate a spin voltage and an associated spin current flow in the system, which makes such nanostructures particularly interesting for future thermoelectric applications. In this study, by using the numerical renormalization group method, we examine the spin-dependent thermoelectric transport properties of a molecular junction involving an orbital level with attractive Coulomb correlations coupled to ferromagnetic leads. We analyze how attractive correlations affect the spin-resolved transport properties of the system and find a nontrivial dependence of the conductance and tunnel magnetoresistance on the strength and sign of those correlations. We also demonstrate that attractive correlations can lead to an enhancement of the spin thermopower and the figure of merit, which can be controlled by a gate voltage.

  4. Weak dissipative effects on trajectories from the edge of basins of attraction

    Science.gov (United States)

    Jousseph, C. A.; Kruger, T. S.; Manchein, C.; Lopes, S. R.; Beims, M. W.

    2016-08-01

    The purpose of this work is to present convergence properties of regular and chaotic conservative trajectories under small dissipation. It is known that when subjected to dissipation, stable periodic points become sinks attracting the surrounding trajectories which belong to rational/irrational tori, while chaotic trajectories converge to a chaotic attractor, if it exists. Using the standard map and a mixed plot we show that this simple scenario can be rather complicated and strongly depends on the dissipation intensity. For small dissipations the huge amount of attractors of the phase-space generates a complicated and intricate dynamics where trajectories are steered to their attractors based on the local (non)hyperbolicity, measured by the Lyapunov vectors. Dissipation creates holes (or attracting channels) on the torus from the conservative limit and allows trajectories to penetrate it. These holes are regions of large local hyperbolicity and are related to sticky channels reported recently. For stronger dissipation sinks tend to attract all trajectories, prevailing over the chaotic attractor.

  5. Parasitoid- and hyperparasitoid-mediated seasonal dynamics of the cabbage aphid (Hemiptera: Aphididae).

    Science.gov (United States)

    Nematollahi, Mohammad Reza; Fathipour, Yaghoub; Talebi, Ali Asghar; Karimzadeh, Javad; Zalucki, Myron Philip

    2014-12-01

    The population dynamics of the cabbage aphid, Brevicoryne brassicae (L.), its parasitoid, Diaeretiella rapae McIntosh, and hyperparasitoids, Pachyneuron spp., were quantified under field conditions during 2011-2013, by examining synchronization, parasitoid: aphid ratio, possible effect of density on the finite rate of increase, and spatial coincidence. The rates of parasitism and hyperparasitism were based on rearing field-collected mummies and live parasitized aphids, and density of the aphid were estimated using heat extraction and subsampling techniques. Only one parasitoid, D. rapae (80% on average), and two hyperparasitoid species from the genus of Pachyneuron (6.5% on average), namely Pachyneuron aphidis (Bouché) and Pachyneuron groenlandicum (Holmgren), were reared from the aphid mummies. Significant Pearson's time lagged correlations for percentage parasitism versus aphid density and for percentage hyperparasitism versus mummy density indicated that 2-3 wk is needed for D. rapae and Pachyneuron spp. to show impact on their respective host's population. In early spring, the parasitoid: aphid ratio was low (0.11 on average) while aphid density was increasing. Based on Taylor's power law, D. rapae and Pachyneuron spp., as well as B. brassicae, had an aggregated distribution among canola plants. Moreover, a high degree of spatial overlap was found between D. rapae and B. brassicae and between Pachyneuron spp. and D. rapae. In general, the parasitoid had good spatial coincidence with its aphid host but because of a lack of parasitoid-host synchronization and low parasitoid: aphid ratio, impact on the host population was low. PMID:25479198

  6. The tritrophic system hyptis suaveolens (Lamiaceae - agromyzid leafminers (Diptera: Agromyzidae - parasitoids (Hymenoptera: effects of herbivore density, host plant patch size, and habitat complexity on parasitism rate

    Directory of Open Access Journals (Sweden)

    Jarbas Marcal de Queiroz

    2009-06-01

    Full Text Available In this study a tritrophic system was evaluated to measure the contributions of the insect host density and its host plant concentration in simple and diversified habitat on the rate of parasitism. The system was composed of the plant Hyptis suaveolens, two species of agromyzid leafminers, and three morphospecies of parasitoids. The parasitism rate, patch size, and habitat complexity were found to be interdependent. If only the habitat complexity or patch size was take into account the differences in parasitism rate are not significant, although habitat diversity seemed to contribute more than the host plant concentration to increase the parasitism rate. The leaves or plants with different number of mines were equally attacked by the parasitoids. The results were representative of what happened to the leafminers at different host plant densities under the homogeneous and heterogeneous habitat condition. This work could help to reinforce the idea of the importance of the plant diversity for enhancing the biological control of the pests by the parasitoids in the managed ecosystems.Foi avaliado um sistema tritrófico para medir os efeitos da densidade de insetos minadores e a concentração da planta hospedeira em habitats simples e diversificados sobre a taxa de parasitismo. O sistema era composto pela planta Hyptis suaveolens, duas espécies de agromizídeos minadores de folhas e três morfoespécies de parasitóides. A taxa de parasitismo, tamanho da mancha e a complexidade do habitat foram interdependentes. Se levarmos em consideração apenas a complexidade ou tamanho de mancha, as diferenças na taxa de parasitismo não foram significativas, embora a diversidade de habitat pareça ter contribuido mais do que a concentração da planta hospedeira para aumentar a taxa de parasitismo. Folhas ou plantas com diferentes números de minas foram igualmente parasitadas. Nossos resultados são representativos do que acontece com insetos minadores em

  7. Chemical cues from the coffee berry borer influence the locomotory behaviour of its bethylid parasitoids.

    Science.gov (United States)

    Chiu-Alvarado, P; Valle-Mora, J; Rojas, J C

    2010-12-01

    Cephalonomia stephanoderis and Prorops nasuta are two bethylid wasps released into several Latin American countries for classical biological control of coffee berry borer, Hypothenemus hampei, the most serious insect pest of coffee worldwide. Recent studies on the host location behaviour of these parasitoids have shown that females of both species are attracted to volatile compounds released by immature stages and dust and frass of H. hampei. In this study, we investigated the role of the contact chemicals present in dust and frass of H. hampei on the behaviour of P. nasuta and C. stephanoderis females. Parasitoids remained longer on patches treated with methanol extracts than on acetone and hexane extracts. Females spent more time on the patch treated with the methanol extract of dust and frass than on the patches treated with the methanol extract of dry coffee and methanol control. The concentration of the methanol extracts from dust and frass influenced the locomotory activity of parasitoids of both species. The time that females spent in the patch tended to increase as the concentration of the methanol extracts increased. A further experiment aimed to identify other behavioural descriptors and gain a deeper understanding of the mechanisms underlying the response of parasitoids to methanol extracts was performed. Females of both species spent more time, covered more distance, turned more (per unit time and per unit distance), and decreased their speed when they contacted patches treated with methanol extracts in comparison to patches treated with methanol control. PMID:20307343

  8. An analysis of the influence of discount sales promotion in consumer buying intent and the moderating effects of attractiveness

    Directory of Open Access Journals (Sweden)

    Fernando de Oliveira Santini

    2015-12-01

    Full Text Available ABSTRACT The purpose of this paper is to analyze the influence of discount sales promotion in the purchase intention and the moderating effects of attractiveness in the relationship between intention to purchase a discounted product and the impulsiveness, hedonic perception and financial risk. Thus, an experiment involving 613 students was conducted. The hypotheses predicted that a product with discount promotion would relate positively with impulsivity, as well as with a hedonic perception about the good offered, and negatively with the perception of financial risk associated with the product offered with discount. A positive moderation was expected of the perceived attractiveness of the announced discount promotion on the intentions of behaviors. The results confirmed the hypothesis, indicating positive effects of impulsivity and hedonic perception by purchasing the discounted products, in addition to the negative link between the intention of purchasing discounted products and the perception of a financial risk. The moderating effects were not confirmed. Final considerations conclude the work.

  9. Effect of attractive interactions on the water-like anomalies of a core-softened model potential

    Energy Technology Data Exchange (ETDEWEB)

    Pant, Shashank [Department of Chemical Sciences, Indian Institute of Science Education and Research-Kolkata, Mohanpur-741252 (India); Gera, Tarun [Department of Chemistry, Indian Institute of Technology-Delhi, New Delhi, 110016 (India); Choudhury, Niharendu, E-mail: nihcho@barc.gov.in, E-mail: niharc2002@yahoo.com [Theoretical Chemistry Section, Bhabha Atomic Research Centre, Mumbai-400 085 (India)

    2013-12-28

    It is now well established that water-like anomalies can be reproduced by a spherically symmetric potential with two length scales, popularly known as core-softened potential. In the present study we aim to investigate the effect of attractive interactions among the particles in a model fluid interacting with core-softened potential on the existence and location of various water-like anomalies in the temperature-pressure plane. We employ extensive molecular dynamic simulations to study anomalous nature of various order parameters and properties under isothermal compression. Order map analyses have also been done for all the potentials. We observe that all the systems with varying depth of attractive wells show structural, dynamic, and thermodynamic anomalies. As many of the previous studies involving model water and a class of core softened potentials have concluded that the structural anomaly region encloses the diffusion anomaly region, which in turn, encloses the density anomaly region, the same pattern has also been observed in the present study for the systems with less depth of attractive well. For the systems with deeper attractive well, we observe that the diffusion anomaly region shifts toward higher densities and is not always enclosed by the structural anomaly region. Also, density anomaly region is not completely enclosed by diffusion anomaly region in this case.

  10. Effect of attractive interactions on the water-like anomalies of a core-softened model potential.

    Science.gov (United States)

    Pant, Shashank; Gera, Tarun; Choudhury, Niharendu

    2013-12-28

    It is now well established that water-like anomalies can be reproduced by a spherically symmetric potential with two length scales, popularly known as core-softened potential. In the present study we aim to investigate the effect of attractive interactions among the particles in a model fluid interacting with core-softened potential on the existence and location of various water-like anomalies in the temperature-pressure plane. We employ extensive molecular dynamic simulations to study anomalous nature of various order parameters and properties under isothermal compression. Order map analyses have also been done for all the potentials. We observe that all the systems with varying depth of attractive wells show structural, dynamic, and thermodynamic anomalies. As many of the previous studies involving model water and a class of core softened potentials have concluded that the structural anomaly region encloses the diffusion anomaly region, which in turn, encloses the density anomaly region, the same pattern has also been observed in the present study for the systems with less depth of attractive well. For the systems with deeper attractive well, we observe that the diffusion anomaly region shifts toward higher densities and is not always enclosed by the structural anomaly region. Also, density anomaly region is not completely enclosed by diffusion anomaly region in this case. PMID:24387380

  11. Effect of attractive interactions on the water-like anomalies of a core-softened model potential

    International Nuclear Information System (INIS)

    It is now well established that water-like anomalies can be reproduced by a spherically symmetric potential with two length scales, popularly known as core-softened potential. In the present study we aim to investigate the effect of attractive interactions among the particles in a model fluid interacting with core-softened potential on the existence and location of various water-like anomalies in the temperature-pressure plane. We employ extensive molecular dynamic simulations to study anomalous nature of various order parameters and properties under isothermal compression. Order map analyses have also been done for all the potentials. We observe that all the systems with varying depth of attractive wells show structural, dynamic, and thermodynamic anomalies. As many of the previous studies involving model water and a class of core softened potentials have concluded that the structural anomaly region encloses the diffusion anomaly region, which in turn, encloses the density anomaly region, the same pattern has also been observed in the present study for the systems with less depth of attractive well. For the systems with deeper attractive well, we observe that the diffusion anomaly region shifts toward higher densities and is not always enclosed by the structural anomaly region. Also, density anomaly region is not completely enclosed by diffusion anomaly region in this case

  12. Effect of Different Pollinator Attractant Crops for Seed Setting and Maximizing Seed Yield of Onion

    OpenAIRE

    Md. Kalim Uddin; Kamal, M.M.; M. M. Akand; Hasan, M. M.; M. N. A. Chowdhury

    2015-01-01

    The experiment was conducted at the Spices Research Centre, Shibgonj, Bogra during rabi season, 2010-11and 2011-12 to identify the suitable pollinator attractant crops for increasing the vigilance of pollinators and higher seed settings and thereby increasing seed yield of onion. In 2010-11, the highest seed setting was recorded in onion + fennel (69.88%) which was statistically identical to Onion + coriander (67.45 %) and Onion + black cumin (64.15 %) while the highest seed setting was recor...

  13. The differential effects of switching costs and attractiveness of alternatives on customer loyalty

    OpenAIRE

    Magalhães, Sara Henriques de Jesus Paninho

    2009-01-01

    Dissertação apresentada como requisito parcial para obtenção do grau de Mestre em Estatística e Gestão de Informação. There is an increasing recognition among marketing scholars and practitioners of the importance of the influence of switching costs and attractiveness of alternatives in the relationship between customer satisfaction and customer loyalty. To date, however, there is a lack of research about the process through which these variables influence the satisfaction-loyalty...

  14. Behavioral and developmental effects of neem extracts on Clavigralla scutellaris (Hemiptera: Heteroptera: Coreidae) and its egg parasitoid, Gryon fulviventre (Hymenoptera: Scelionidae).

    Science.gov (United States)

    Mitchell, Paula Levin; Gupta, Reetika; Singh, Ashok K; Kumar, Pradyumn

    2004-06-01

    Extracts of neem, Azadirachta indica A. Juss, negatively affected feeding and development of Clavigralla scutellaris (Westwood), a coreid pest of pigeonpea, Cajanus cajan (L.) Millspaugh. Labial dabbing, pod wall penetration, and seed damage by fifth instars were significantly reduced on beans, Phaseolus vulgaris (L.), that had been dipped in aqueous, methanolic, or hexane extracts of neem seed kernel. When fourth instars were dipped directly into aqueous extract, developmental abnormalities of the wings occurred at all levels tested and fecundity dropped to zero at concentrations above 0.3125%. The LC50 value was 3.14% (220 ppm azadirachtin) at 8 d. The scelionid wasp Gryon fulviventre (Crawford) is an important natural enemy of Clavigralla spp.; egg mortality from this parasitoid ranged from 37 to 85% during the fall cropping season. Feeding by newly emerged wasps was dramatically reduced when honey was mixed with aqueous neem suspension, but 6-d survivorship of adults did not differ significantly from that of the control. Wasp oviposition behavior was altered slightly when coreid eggs were treated with neem: the period of antennation was significantly extended, but time for drilling, oviposition, and marking was unaffected. Neem-dipped eggs were accepted for oviposition and progeny emerged successfully from these treated eggs. Exposure of already parasitized eggs to neem did not interfere with progeny emergence, longevity, or sex ratio. Thus, neem extract and egg parasitoids seem to be compatible and promising control strategies for C. scutellaris. Our results suggest that use of neem against pod-sucking bugs will not interfere with natural control provided by G. fulviventre. PMID:15279272

  15. Effect of Different Pollinator Attractant Crops for Seed Setting and Maximizing Seed Yield of Onion

    Directory of Open Access Journals (Sweden)

    Md. Kalim Uddin

    2015-12-01

    Full Text Available The experiment was conducted at the Spices Research Centre, Shibgonj, Bogra during rabi season, 2010-11and 2011-12 to identify the suitable pollinator attractant crops for increasing the vigilance of pollinators and higher seed settings and thereby increasing seed yield of onion. In 2010-11, the highest seed setting was recorded in onion + fennel (69.88% which was statistically identical to Onion + coriander (67.45 % and Onion + black cumin (64.15 % while the highest seed setting was recorded in Onion + Fennel (73.70 % which was identical to Onion + Dill (70.50% and Onion + Coriander( 72.37% during 2011-12. In 2010-11, the highest seed yield (865.5 kg/ha was obtained from Onion + fennel which was identical to Onion + coriander (838.1 kg/ha but in 2011-12, the highest seed yield (1165.34 kg/ha was recorded from Onion + fennel which was identical to Onion + coriander (1064.59 kg/ha. In both the years, percent seed setting was lowest in Sole onion (55.93 % in 2010-11and 57.73% in 2011-12. Accordingly, the lowest seed yield was also recorded from Sole onion (623.3 kg/ha in 2010-11 and 685.44 kg/ha in 2011-12. Dill and Fennel was the better attractant crop for pollination while coriander acted as intermediate.

  16. The use of Aedes aegypti larvae attractants to enhance the effectiveness of larvicides.

    Science.gov (United States)

    Gonzalez, Paula V; Harburguer, Laura; González-Audino, Paola A; Masuh, Héctor M

    2016-06-01

    Aedes aegypti (L.) is an important dengue, chikungunya, and yellow fever vector. Immature stages of this species inhabit human-made containers placed in residential landscapes, and the application of larvicides inside containers that cannot be eliminated is still considered a priority in control programs. Larvicidal efficacy is influenced by several factors, including the formulation used, the water quality, and the susceptibility of larvae, among others. If an attractant can be incorporated into a slow-release larvicide formulation, it will be feasible to direct the larvae into the source of insecticide and thereby improving its efficacy. We studied the influence of 1-octen-3ol and 3-methylphenol on the rate of Ae. aegypti larvae mortality using the larvicides Bacillus thuringiensis var. israelensis (Bti), temephos, and spinosad. These chemicals were combined with the larvicides mixed with agar during the bioassays. Mortality was registered every 10 min, and a lethal time 50 (LT50) was calculated. The inclusion of the Ae. aegypti larvae attractants with the larvicides into a solid agar matrix improved their efficiency obtaining a strong and marked reduction in the LT50 compared with the use of larvicides alone. PMID:26922177

  17. The Effect of Incobotulinumtoxin A and Dermal Filler Treatment on Perception of Age, Health, and Attractiveness of Female Faces

    OpenAIRE

    Fink, Bernhard; Prager, Michael

    2014-01-01

    Objectives: Facial age, health, and attractiveness assessments play a major role in human social interaction and affect the way we perceive and think about others. Modern cosmetic dermatology provides a bewildering array of facial treatment procedures with botulinum toxin type A and dermal filler application being the most requested. The authors sought to determine the effect of facial rejuvenation procedures, such as application of incobotulinumtoxin A and dermal filler injections, on people...

  18. Distributed attraction: the effects of street network connectivity upon the distribution of retail frontage in the City of Buenos Aires

    OpenAIRE

    Martin D Scoppa; John Peponis

    2015-01-01

    The City of Buenos Aires has a radial street plan, regular blocks, and a clear central place. On the basis of an analysis of the city’s GIS database, we show that measures describing the syntax of its street network have a significant relationship with commercial frontage density, over and above the impact of central business district attraction. These results are obtained while controlling for the effects of population and employment density, distance from public transportation stations, and...

  19. An analysis of the influence of discount sales promotion in consumer buying intent and the moderating effects of attractiveness

    OpenAIRE

    Fernando de Oliveira Santini; Cláudio Hoffmann Sampaio; Marcelo Gattermann Perin; Valter Afonso Vieira

    2015-01-01

    ABSTRACT The purpose of this paper is to analyze the influence of discount sales promotion in the purchase intention and the moderating effects of attractiveness in the relationship between intention to purchase a discounted product and the impulsiveness, hedonic perception and financial risk. Thus, an experiment involving 613 students was conducted. The hypotheses predicted that a product with discount promotion would relate positively with impulsivity, as well as with a hedonic perception a...

  20. Temporal autocorrelation in host density increases establishment success of parasitoids in an experimental system.

    Science.gov (United States)

    Vercken, Elodie; Fauvergue, Xavier; Ris, Nicolas; Crochard, Didier; Mailleret, Ludovic

    2015-07-01

    Environmental variation is classically expected to affect negatively population growth and to increase extinction risk, and it has been identified as a major determinant of establishment failures in the field. Yet, recent theoretical investigations have shown that the structure of environmental variation and more precisely the presence of positive temporal autocorrelation might alter this prediction. This is particularly likely to affect the establishment dynamics of biological control agents in the field, as host-parasitoid interactions are expected to induce temporal autocorrelation in host abundance. In the case where parasitoid populations display overcompensatory dynamics, the presence of such positive temporal autocorrelation should increase their establishment success in a variable environment. We tested this prediction in laboratory microcosms by introducing parasitoids to hosts whose abundances were manipulated to simulate uncorrelated or positively autocorrelated variations in carrying capacity. We found that environmental variability decreased population size and increased parasitoid population variance, which is classically expected to extinction risk. However, although exposed to significant environmental variation, we found that parasitoid populations experiencing positive temporal autocorrelation in host abundance were more likely to persist than populations exposed to uncorrelated variation. These results confirm that environmental variation is a key determinant of extinction dynamics that can have counterintuitive effects depending on its autocorrelation structure. PMID:26257880

  1. Tritrophic interactions between parasitoids and cereal aphids are mediated by nitrogen fertilizer.

    Science.gov (United States)

    Aqueel, Muhammad A; Raza, Abu-bakar M; Balal, Rashad M; Shahid, Muhammad A; Mustafa, Irfan; Javaid, Muhammad M; Leather, Simon R

    2015-12-01

    Host plant nutritional quality can directly and indirectly affect the third trophic levels. The aphid-parasitoid relationship provides an ideal system to investigate tritrophic interactions (as the parasitoids are completely dependent for their development upon their hosts) and assess the bottom up forces operating at different concentrations of nitrogen applications. The effects of varying nitrogen fertilizer on the performance of Aphidius colemani (V.) reared on Sitobion avenae (F.) and Aphidius rhopalosiphi (D.) reared on Rhopalosiphum padi (L.) were measured. Parasitism and percent emergence of parasitoids were positively affected by nitrogen fertilizer treatments while developmental duration (egg, larval, and pupal stages) was not affected by increasing nitrogen inputs. In males and females of both parasitoid species, adult longevity increased with the increasing nitrogen fertilizer. Hind tibia length and mummy weight of both parasitoid species increased with nitrogen fertilizer concentrations, as a result of larger aphids. This study showed that nitrogen application to the soil can have important consequences for aboveground multitrophic interactions. PMID:24623663

  2. The relationship between variable host grouping and functional responses among parasitoids of Antispila nysaefoliella (Lepidoptera: Heliozelidae).

    Science.gov (United States)

    Low, Candace; Scheffer, Sonja J; Lewis, Matthew L; Gates, Michael W

    2012-12-01

    Our study investigated the importance of variability in the parasitoid community as a source of selection on host group size using a field population of the tupelo leafminer, Antispila nysaefoliella Clemens, which specializes on tupelo, Nyssa sylvatica Marsh. Larvae were collected from leaves with variable numbers of larvae and screened for parasitism using polymerase chain reaction of mitochondrial cytochrome oxidase I using markers designed specifically for amplifying parasitoid DNA while excluding host DNA. This method of selective PCR was effective for detecting the presence and identifying species of immature stages of three hymenopteran superfamilies: Chalcidoidea, Ichneumonoidea and Platygastroidea, which represented 83.4%, 16.0% and 0.6% of the total detectable parasitism, respectively. Our resulting sequences were then calibrated with sequences from identified adult parasitoids that had been either reared or field-captured. A cluster analysis revealed 10 distinct clades that showed differences in attack patterns with respect to host traits and season. Total parasitism followed an inverse density-dependent or density-independent pattern with respect to host density (number per leaf). However, when parasitoid taxa were considered separately, one clade, which could be a cryptic species of Pnigalio maculipes Crawford (Chalcidoidea: Eulophidae), was found to increase its per leaf attack rate with host density. Our results suggest that parasitoid community composition and differences among species in their attack strategies can play a large role in determining the adaptive advantage of host grouping. PMID:23094653

  3. Impact of five insecticides used to control citrus pests on the parasitoid Ageniaspis citricola Longvinovskaya (Hymenoptera: Encyrtidae).

    Science.gov (United States)

    de Morais, Matheus Rovere; Zanardi, Odimar Zanuzo; Rugno, Gabriel Rodrigo; Yamamoto, Pedro Takao

    2016-07-01

    The parasitoid Ageniaspis citricola Longvnovskaya is a main biological control agent of the citrus leafminer Phyllocnistis citrella Stainton, an insect pest that causes considerable damage to citrus worldwide. However, the use of pesticides to control arthropod pests can reduce the effectiveness of parasitoids and disrupt integrated pest management in citrus groves. This study evaluated the impact on A. citricola of five insecticides that are used to control arthropod pests in citrus. Our results indicated that imidacloprid, chlorpyrifos, bifenthrin and β-cyfluthrin were harmful (mortality >89 %) to A. citricola adults; whereas abamectin did not cause significant mortality and was considered harmless to the parasitoid. In addition to causing high mortality, imidacloprid and bifenthrin were considered moderately persistent, because they caused control treatment. Therefore, semi-field and field studies that consider demographic parameters are needed to evaluate the impacts of these insecticides on the A. citricola parasitoid. PMID:27146672

  4. Attention Alters Perceived Attractiveness.

    Science.gov (United States)

    Störmer, Viola S; Alvarez, George A

    2016-04-01

    Can attention alter the impression of a face? Previous studies showed that attention modulates the appearance of lower-level visual features. For instance, attention can make a simple stimulus appear to have higher contrast than it actually does. We tested whether attention can also alter the perception of a higher-order property-namely, facial attractiveness. We asked participants to judge the relative attractiveness of two faces after summoning their attention to one of the faces using a briefly presented visual cue. Across trials, participants judged the attended face to be more attractive than the same face when it was unattended. This effect was not due to decision or response biases, but rather was due to changes in perceptual processing of the faces. These results show that attention alters perceived facial attractiveness, and broadly demonstrate that attention can influence higher-level perception and may affect people's initial impressions of one another. PMID:26966228

  5. Judging attractiveness: Biases due to raters’ own attractiveness and intelligence

    OpenAIRE

    Stacy Yen-Lin Sim; Jenna Saperia; Jill Anne Brown; Frank John Bernieri

    2015-01-01

    Tennis and Dabbs (1975) reported that physically attractive males showed a positivity bias when rating the attractiveness of others. The opposite pattern was observed for females. We attempted to replicate and extend these findings by: (1) using self-assessed attractiveness rather than the experimentally derived attractiveness measure used in previous research, (2) using face-to-face interactions with targets as opposed to using photographs, and (3) examining the effect of another ego-involvi...

  6. The Tip-Induced Twisted Bilayer Graphene Superlattice on HOPG: Capillary Attraction Effect

    CERN Document Server

    Yin, Long Jing; Feng, Ke Ke; Dou, Rui-Fen; Nie, Jia-Cai

    2014-01-01

    We use the tip of the scanning tunneling microscope (STM) to manipulate single weakly bound nanometer-sized sheets on the the highly oriented pyrolytic graphite (HOPG) surface through artifically increasing the tip and sample interaction in humid environment. By this means it is possible to tear apart a graphite sheet againt a step and fold this part onto the HOPG surface and thus generate the gaphene superlattices with hexagonal symmetry. The tip and sample surface interactions, including the van der Waals force, eletrostatic force and capillary attraction force originating from the Laplace pressure due to the formation of a highly curved fluid meniscus connecting the tip and sample, are discussed in details to understand the fromation mechnism of graphen superlattice induced by the STM tip. Especially, the capillary force is the key role in manipulating the graphite surface sheet in the hunmidity condition. Our approach may provides a simple and feasible route to prepare the controllable superlattices and g...

  7. Effect of sun-exposure of the horse chestnut (Aesculus hippocastanum L.) on the occurrence and number of parasitoids of the horse chestnut leafminer (Cameraria ohridella Deschka & Dimic) in central Poland in 2004– 2006

    OpenAIRE

    Tarwacki, Grzegorz; Bystrowski, Cezary; Celmer-Warda, Katarzyna

    2012-01-01

    The research on parasitoids of the horse chestnut leafminer (Cameraria ohridella Deschka & Dymić, 1986) of the order Hymenoptera was conducted in the years 2004– 2006 in six locations in central Poland. The complex of para-sitoids was composed of 14 species. Minotetrastrichus frontalis (Nees) and Pnigalio agraules (Walker), (Hyme-noptera: Eulophidae) were the dominant species in all locations. It was noted that sun-exposure of the horse chest-nut (Aesculus hippocastanum L.) had asignificant e...

  8. Electromagnetic Attraction.

    Science.gov (United States)

    Milson, James L.

    1990-01-01

    Three activities involving electromagnetism are presented. Discussed are investigations involving the construction of an electromagnet, the effect of the number of turns of wire in the magnet, and the effect of the number of batteries in the circuit. Extension activities are suggested. (CW)

  9. Effects of reading health and appearance exercise magazine articles on perceptions of attractiveness and reasons for exercise.

    Directory of Open Access Journals (Sweden)

    Melanie Pankratow

    Full Text Available OBJECTIVE: To examine the effects of reading exercise-related magazine articles (health, appearance, or control and the moderating effects of exercise self-identity on reasons for exercise and perceptions of attractiveness, among women in first year university. An additional purpose was to use a thought listing technique, the results of which were examined for evidence of internalization of the exercise-related messages. PARTICIPANTS: Female students in their first year of studies between September 2010 and April 2011 (N = 173; mean age = 19.31 years, mean body mass index = 22.01. METHODS: Participants read a health, appearance, or control article, listed thoughts, and completed questionnaires measuring reasons for exercising, physical self-perception, and exercise self-identity. RESULTS: Participants in the health condition rated exercise for health significantly higher than control condition participants. Participants with high exercise self-identity rated attractiveness as a reason for exercising significantly higher than low exercise self-identity participants in both the health and appearance conditions. Participants with higher internalization scores (i.e., accepted societal norms of appearance reported exercising for attractiveness reasons more so than participants with lower internalization scores. CONCLUSIONS: The good news is that health messages may be influential and result in wanting to exercise for health purposes. However, exercising for attractiveness was rated highly by participants with high exercise identity who read either the health or appearance articles. Health and appearance are not necessarily distinct concepts for female undergraduate students and the media may influence cited reasons for exercise.

  10. Differential thermal performance curves in response to different habitats in the parasitoid Venturia canescens

    Science.gov (United States)

    Foray, Vincent; Gibert, Patricia; Desouhant, Emmanuel

    2011-08-01

    Environmental variability is expected to be important in shaping performance curves, reaction norms of phenotypic traits related to fitness. Models predict that the breadth of performance curves should increase with environmental variability at the expense of maximal performance. In this study, we compared the thermal performance curves of two sympatric populations of the parasitoid Venturia canescens that were observed under contrasting thermal regimes in their respective preferred habitats and differing in their modes of reproduction. Our results confirm the large effect of developmental temperature on phenotypic traits of insects and demonstrate that thelytokous and arrhenotokous wasps respond differently to temperature during development, in agreement with model predictions. For traits related to fecundity, thelytokous parasitoids, which usually occur in stable thermal conditions, exhibit specialist performance curves, maximising their reproductive success under a restricted range of temperature. In contrast, arrhenotokous parasitoids, which occur in variable climates, exhibit generalist performance curves, in keeping with the hypothesis "jack of all temperatures, master of none".

  11. The Roles of Parasitoid Foraging for Hosts, Food and Mates in the Augmentative Control of Tephritidae

    Directory of Open Access Journals (Sweden)

    Martin Aluja

    2012-07-01

    Full Text Available Ultimately, the success of augmentative fruit fly biological control depends upon the survival, dispersal, attack rate and multi-generational persistence of mass-reared parasitoids in the field. Foraging for hosts, food and mates is fundamental to the above and, at an operational level, the choice of the parasitoid best suited to control a particular tephritid in a certain environment, release rate estimates and subsequent monitoring of effectiveness. In the following we review landscape-level and microhabitat foraging preferences, host/fruit ranges, orientation through environmental cues, host vulnerabilities/ovipositor structures, and inter and intraspecific competition. We also consider tephritid parasitoid mating systems and sexual signals, and suggest the directions of future research.

  12. Effect of adult diet on signaling activity, mate attraction, and mating success in male Mediterranean fruit flies (Diptera: Tephritidae)

    International Nuclear Information System (INIS)

    Field experiments were performed to examine the effect of adult diet on calling activity, female attraction, and mating success in male Mediterranean fruit flies, Ceratitis capitata (Wiedemann). In all tests, comparisons were drawn between males fed sugar only ('protein-deprived' males) and males fed a protein-sugar mixture ('protein-fed' males). In tests of long-distance attraction, aggregations consisting of protein-deprived males exclusively or protein-fed males exclusively were established in a coffee field, and females were released from a central release point. Protein-fed and protein-deprived males displayed similar calling levels, but approximately twice as many female sightings were recorded at groups of protein-fed males than at groups of protein-deprived males. A second test of female attraction compared single groups of protein-deprived and protein-fed males within the canopy of a field-caged host plant. As before, calling activity did not vary with diet, and in this case numbers of female sightings were also similar between aggregations of protein-fed vs. protein-deprived males. In mating trials conducted on field-caged host plants, protein-fed males achieved significantly more matings than protein-deprived males. These results are compared with other recent studies on the nutritional ecology of male Mediterranean fruit flies. (author)

  13. The native ant, Tapinoma melanocephalum, improves the survival of an invasive mealybug, Phenacoccus solenopsis, by defending it from parasitoids.

    Science.gov (United States)

    Feng, Dong-Dong; Michaud, J P; Li, Pan; Zhou, Zhong-Shi; Xu, Zai-Fu

    2015-01-01

    Mutualistic ants can protect their partners from natural enemies in nature. Aenasius bambawalei is an important parasitoid of the the invasive mealybug Phenacoccus solenopsis. We hypothesized that mutualism between native ants and mealybugs would favor survival of mealybugs. To test this, we examined effects of tending by the native mutualistic ant Tapinoma melanocephalum on growth of P. solenopsis colonies on Chinese hibiscus, Hibiscus rosa-sinensis, in a field setting. Ant workers with access to honeydew of mealybugs lived much longer than those provisioned only with water in the laboratory, and number of ant workers foraging increased significantly with growth of mealybug colonies in the field. In later observations, there were significant differences in densities of mealybugs between ant-tended and -excluded treatments. Survival rate of mealybugs experiencing parasitoid attack was significantly higher on ant-tended plants than on ant-excluded plants. When the parasitoid was excluded, there was no difference in survival rate of mealybugs between ant-tended and -excluded plants. In most cases, ants directly attacked the parasitoid, causing the parasitoid to take evasive action. We conclude that native ants such as T. melanocephalum have the potential to facilitate invasion and spread of P. solenopsis in China by providing them with protection from parasitoids. PMID:26503138

  14. Evaluation of the community of native eulophid parasitoids on Cameraria ohridella Deschka and Dimic in urban areas.

    Science.gov (United States)

    Ferracini, Chiara; Alma, Alberto

    2007-10-01

    The parasitoid complex associated with the exotic leafminer Cameraria ohridella Deschka and Dimic (Lepidoptera: Gracillariidae), which attacks horse chestnut (Aesculus hippocastanum L.), was studied in the urban environment of Turin (northern Italy). The studies were carried out over 5 yr after the first detection of the pest in our region in 1999. To evaluate parasitism, 438,029 leaf mines were examined over the 5-yr period, of which 29,033 were found to be parasitized (6.6%). Also, ornamental broadleaf trees attacked by other native gracillariid leafminers and located in the proximity of the target horse chestnut trees were sampled. A total of 11 parasitoid species (Hymenoptera: Eulophidae) were recorded on C. ohridella, and the most common species were Minotetrastichus frontalis (Nees), Closterocerus trifasciatus Westwood, and Pnigalio agraules (Walker). The first species accounted for >77.5% of all parasitoids collected. Cirrospilus talitzkii Boucek was found for the first time in 2005. The high population level of the pest and the low parasitism rate show that the parasitoid complex is currently inadequate to contain C. ohridella populations effectively. The most frequent parasitoids of the moth were also found on the most common broadleaf trees in the studied area, showing how native leafminer parasitoid species are able to switch to other hosts. These results show that both native and broadleaf plants species may potentially provide an important reservoir of parasitic wasps to help protect a simple biotope, such as the urban environment, from pests. PMID:18284739

  15. A new approach for investigating venom function applied to venom calreticulin in a parasitoid wasp.

    Science.gov (United States)

    Siebert, Aisha L; Wheeler, David; Werren, John H

    2015-12-01

    A new method is developed to investigate functions of venom components, using venom gene RNA interference knockdown in the venomous animal coupled with RNA sequencing in the envenomated host animal. The vRNAi/eRNA-Seq approach is applied to the venom calreticulin component (v-crc) of the parasitoid wasp Nasonia vitripennis. Parasitoids are common, venomous animals that inject venom proteins into host insects, where they modulate physiology and metabolism to produce a better food resource for the parasitoid larvae. vRNAi/eRNA-Seq indicates that v-crc acts to suppress expression of innate immune cell response, enhance expression of clotting genes in the host, and up-regulate cuticle genes. V-crc KD also results in an increased melanization reaction immediately following envenomation. We propose that v-crc inhibits innate immune response to parasitoid venom and reduces host bleeding during adult and larval parasitoid feeding. Experiments do not support the hypothesis that v-crc is required for the developmental arrest phenotype observed in envenomated hosts. We propose that an important role for some venom components is to reduce (modulate) the exaggerated effects of other venom components on target host gene expression, physiology, and survival, and term this venom mitigation. A model is developed that uses vRNAi/eRNA-Seq to quantify the contribution of individual venom components to total venom phenotypes, and to define different categories of mitigation by individual venoms on host gene expression. Mitigating functions likely contribute to the diversity of venom proteins in parasitoids and other venomous organisms. PMID:26359852

  16. Experimental Effects and Individual Differences in Linear Mixed Models: Estimating the Relation of Spatial, Object, and Attraction Effects in Visual Attention

    Directory of Open Access Journals (Sweden)

    ReinholdKliegl

    2011-01-01

    Full Text Available Linear mixed models (LMMs provide a still underused methodological perspective on combining experimental and individual-differences research. Here we illustrate this approach with two-rectangle cueing in visual attention (Egly, Driver, & Rafal, 1994. We replicated previous experimental cue-validity effects relating to a spatial shift of attention within an object (spatial effect, to attention switch between objects (object effect, and to the attraction of attention towards the display centroid (attraction effect, taking also into account the design-inherent imbalance of valid and other trials. We simultaneously estimated variance/covariance components of subject-related random effects for these spatial, object, and attraction effects in addition to their mean RTs. The spatial effect showed a strong positive correlation with mean RT and a strong negative correlation with the attraction effect. The analysis of individual differences suggests that slow subjects engage attention more strongly at the cued location than fast subjects. We compare this joint LMM analysis of experimental effects and associated subject-related variances and correlations with two alternative, frequently used, statistical procedures.

  17. Insect attraction to herbivore-induced beech volatiles under different forest management regimes.

    Science.gov (United States)

    Gossner, Martin M; Weisser, Wolfgang W; Gershenzon, Jonathan; Unsicker, Sybille B

    2014-10-01

    Insect herbivore enemies such as parasitoids and predators are important in controlling herbivore pests. From agricultural systems we know that land-use intensification can negatively impact biological control as an important ecosystem service. The aim of our study was to investigate the importance of management regime for natural enemy pressure and biological control possibilities in forests dominated by European beech. We hypothesize that the volatile blend released from herbivore-infested beech trees functions as a signal, attracting parasitoids and herbivore enemies. Furthermore, we hypothesize that forest management regime influences the composition of species attracted by these herbivore-induced beech volatiles. We installed flight-interception traps next to Lymantria dispar caterpillar-infested young beech trees releasing herbivore-induced volatiles and next to non-infested control trees. Significantly more parasitoids were captured next to caterpillar-infested trees compared to non-infested controls, irrespective of forest type. However, the composition of the trophic guilds in the traps did vary in response to forest management regime. While the proportion of chewing insects was highest in non-managed forests, the proportion of sucking insects peaked in forests with low management and of parasitoids in young, highly managed, forest stands. Neither the number of naturally occurring beech saplings nor herbivory levels in the proximity of our experiment affected the abundance and diversity of parasitoids caught. Our data show that herbivore-induced beech volatiles attract herbivore enemies under field conditions. They further suggest that differences in the structural complexity of forests as a consequence of management regime only play a minor role in parasitoid activity and thus in indirect tree defense. PMID:25080178

  18. Effects of Cooperative vs Individualistic Learning Experiences on Interpersonl Attraction between Learning-Disabled and Normal-Progress Elementary School Students.

    Science.gov (United States)

    Armstrong, Barbara; And Others

    1981-01-01

    The effects of cooperative and individualistic learning experiences were compared on interpersonal attraction between nonhandicapped students and learning-disabled peers and achievement. Results indicate that greater interpersonal attraction between the learning-disabled and normal-progress students and higher achievement resulted in the…

  19. Instant Attraction: Immediate Action-Effect Bindings Occur for Both, Stimulus- and Goal-Driven Actions

    OpenAIRE

    Janczyk, Markus; Heinemann, Alexander; Pfister, Roland

    2012-01-01

    Flexible behavior is only possible if contingencies between own actions and following environmental effects are acquired as quickly as possible; and recent findings indeed point toward an immediate formation of action-effect bindings already after a single coupling of an action and its effect. The present study explored whether these short-term bindings occur for both, stimulus- and goal-driven actions (“forced-choice actions” vs. “free-choice actions”). Two experiments confirmed that immedia...

  20. Sequential Effects in Judgements of Attractiveness: The Influences of Face Race and Sex

    OpenAIRE

    Robin S S Kramer; Jones, Alex L.; Dinkar Sharma

    2013-01-01

    In perceptual decision-making, a person’s response on a given trial is influenced by their response on the immediately preceding trial. This sequential effect was initially demonstrated in psychophysical tasks, but has now been found in more complex, real-world judgements. The similarity of the current and previous stimuli determines the nature of the effect, with more similar items producing assimilation in judgements, while less similarity can cause a contrast effect. Previous research foun...

  1. Attracting International Hotels

    DEFF Research Database (Denmark)

    Assaf, A. George; Josiassen, Alexander; Agbola, Frank Wogbe

    2015-01-01

    their presence has several positive effects. Using, for the first time, actual on-location data we investigate the factors that matter most for international hotels when selecting host destinations. Specifically, we identify 23 factors that make a destination an attractive (or unattractive) location......With the increased international competition facing hotel chains, it is essential that the next destination they enter is the most attractive option possible. The host destinations too have a keen interest in strategically positioning themselves in order to attract international hotels since...... for international hotels. We then rank these. The results show that welcomeness, infrastructure, and crime rate are the three most important factors that influence the location of international hotels in host destinations....

  2. Instant attraction: Immediate action-effect bindings occur for both, stimulus- and goal-driven actions

    Directory of Open Access Journals (Sweden)

    MarkusJanczyk

    2012-10-01

    Full Text Available Flexible behavior is only possible if contingencies between own actions and following environmental effects are acquired as quickly as possible; and recent findings indeed point toward an immediate formation of action-effect bindings already after a single coupling of an action and its effect. The present study explored whether these short-term bindings occur for both, stimulus- and goal-driven actions (“forced-choice actions” vs. “free-choice actions”. Two experiments confirmed that immediate action-effect bindings are formed for both types of actions and affect upcoming behavior. These findings support the view that action-effect binding is a ubiquitous phenomenon which occurs for any type of action.

  3. The Effects of Social Behavior on Fourth and Fifth Grade Girls' Perceptions of Physically Attractive and Unattractive Peers.

    Science.gov (United States)

    Duncan-Bazil, Lisa; Foster, Sharon L.

    Despite abundant research relating physical attractiveness and social skill, no studies have systematically assessed the influence of social behavior on perceived attractiveness. This study experimentally investigated how exposure to positive, negative, and neutral childhood behaviors influences ratings of physical attractiveness and other social…

  4. Influence of antibiotics on the offspring production of the Wolbachia-infected parthenogenetic parasitoid Encarsia formosa

    NARCIS (Netherlands)

    Stouthamer, R.; Mak, F.

    2002-01-01

    Three different concentrations of the antibiotic tetracycline in honey were tested for their influence on the offspring production and longevity of the parasitoid wasp Encarsia formosa. Several earlier publications did not provide a conclusive answer on the effect that the Wolbachia have on these wa

  5. Combining larval parasitoids and an entomopathogenicfungus for biological control of Sitophilus granarius (Coleoptera: Curculionidae) in stored grain

    DEFF Research Database (Denmark)

    Hansen, Lise Stengaard; Steenberg, Tove

    2006-01-01

    The potential of combining different natural enemies for biological control of Sitophilus granarius (L.) in grain was investigated in a laboratory study. We compared the effect of two species of larval parasitoids, Lariophagus distinguendus Förster and Anisoptermalus calandrae (Howard), alone or in...... suppression (>99.9%) was obtained in units with L. distinguendus, followed by units with A. calandrae. In units with both parasitoids and the entomopathogen, the pest suppression level was 83-98%. Although the parasitoids were negatively affected by the fungus, they still exerted some degree of control...

  6. Aphid parasitoids (Hymenoptera, Braconidae, Aphidiinae) from Thailand

    Czech Academy of Sciences Publication Activity Database

    Starý, Petr; Rakhshani, E.; Tomanović, Ž.; Kavallieratos, N. G.; Sharkey, M.

    -, č. 2498 (2010), s. 47-52. ISSN 1175-5326 Grant ostatní: Ministry of Science of the Republic of Serbia(CS) 143006B; U. S. National Science Foundation(US) DEB 0542864 Institutional research plan: CEZ:AV0Z50070508 Keywords : aphids * parasitoids * biodiversity Subject RIV: EG - Zoology Impact factor: 0.853, year: 2010

  7. Effects of physical attractiveness on evaluations of a male employee's allegation of sexual harassment by his female employer.

    Science.gov (United States)

    Wuensch, Karl L; Moore, Charles H

    2004-04-01

    College students (N = 324) served as mock jurors in a simulated civil case in which a male plaintiff accused a female defendant of sexual harassment. The authors experimentally manipulated the physical attractiveness of the litigants. The authors asked mock jurors to decide whether the defendant was guilty and to rate their certainty of belief in the defendant's guilt (or lack of guilt). Jurors were more certain of the guilt of the defendant when the plaintiff was attractive than when he was unattractive. Plaintiff attractiveness significantly affected female jurors' individual recommended verdicts when the defendant was unattractive but not when she was attractive. With male jurors, plaintiff attractiveness significantly affected their verdicts when the defendant was attractive but not when she was unattractive. Female jurors were more likely than male jurors to conclude that sexual harassment had taken place but only when the litigants were different in attractiveness. PMID:15074507

  8. The endosymbiont Arsenophonus is widespread in soybean aphid, Aphis glycines, but does not provide protection from parasitoids or a fungal pathogen

    Science.gov (United States)

    Aphids commonly harbor bacterial facultative symbionts that have a variety of effects upon their aphid hosts, including defense against hymenopteran parasitoids and fungal pathogens. The soybean aphid, Aphis glycines Matsumura (Hemiptera: Aphididae), is infected with the symbiont, Arsenophonus sp., ...

  9. On sponsoring and CSR involvement. Two theories explaining their effects on a company’s attractiveness for candidates

    Directory of Open Access Journals (Sweden)

    Jacek WOZNIAK

    2014-07-01

    Full Text Available The use of e-recruitment for hiring personnel is constantly expanding. However, the scientific understanding of factors affecting company employer brand during e-recruitment, is still poor. Research into corporate social responsibilities (CSR shows that information about the company’s involvement in these areas makes its image more positive, including its image as an employer. CSR is an umbrella concept, which includes activities similar to traditional sponsoring of sports and cultural events. Two theories explaining the impact of information on attractiveness of the employer’s brand in the e-recruitment process are presented. The aim of the text is to check which of them – cultural fit or signaling theory – more adequately explains the changes in how a candidate perceives a company’s attractiveness, when given information about its’ sports and cultural sponsoring and environment-related activities. The effect of both positive and negative information concerning a company’s activities on its employer image in the e-recruitment situation is analyzed. Data from an questionnaire filled in by 80 young full-time workers shows that positive information about a company’s CSR and sponsoring activities affects candidates according to the cultural fit model, while negative – according to the signaling theory model. The consequences for theory and managerial practice are described.

  10. On sponsoring and CSR involvement. Two theories explaining their effects on a company’s attractiveness for candidates

    Directory of Open Access Journals (Sweden)

    Jacek Wozniak

    2016-04-01

    Full Text Available The use of e-recruitment for hiring personnel is constantly expanding. However, the scientific understanding of factors affecting company employer brand during e-recruitment, is still poor. Research into corporate social responsibilities (CSR shows that information about the company’s involvement in these areas makes its image more positive, including its image as an employer. CSR is an umbrella concept, which includes activities similar to traditional sponsoring of sports and cultural events. Two theories explaining the impact of information on attractiveness of the employer’s brand in the e-recruitment process are presented. The aim of the text is to check which of them – cultural fit or signaling theory – more adequately explains the changes in how a candidate perceives a company’s attractiveness, when given information about its’ sports and cultural sponsoring and environment-related activities. The effect of both positive and negative information concerning a company’s activities on its employer image in the e-recruitment situation is analyzed. Data from an questionnaire filled in by 80 young full-time workers shows that positive information about a company’s CSR and sponsoring activities affects candidates according to the cultural fit model, while negative – according to the signaling theory model. The consequences for theory and managerial practice are described.

  11. Effectiveness of Mosquito Trap with Sugar Fermented Attractant to the Vector of Dengue Hemorrhagic Fever

    Directory of Open Access Journals (Sweden)

    Endang Puji Astuti

    2011-06-01

    Full Text Available Aedes aegypti is the main vector of dengue fever that is still become health problem in the world. Various control efforts has been done at several areas through chemically or naturally control. Developing mosquitoes trapping tool is an alternative method to control mosquitoes besides insecticides utilization. This laboratorium research utilize sugar fermented process to yield CO2 as one of attractan to mosquito. Production of ethanol and CO2 can be yielded from anaerob sugar fermentation proccess (without O2 by khamir Saccharomyces cerevisiae activities. The trapped mosquitoes was observed up to 48 hours exposure, the highest average of mosquito trapped is on solution treatment with yeast 1 gram (43.2% and 40 gr sugar (48.4%. The highest effectivity of trapping tool both inside or outside was on the 14th day. There were declained amount of trapped mosquitos on 16th and 18th days. This laboratorium research has described that trapping tool with sugar fermented solution were effective to control population of dengue vector.

  12. Physical Attractiveness and Counseling Skills.

    Science.gov (United States)

    Vargas, Alice M.; Borkowski, John G.

    1982-01-01

    Searched for interaction between quality of counseling skills (presence or absence of empathy, genuineness, and positive regard) and physical attractiveness as determinants of counseling effectiveness. Attractiveness influenced perceived effectiveness of counselor's skill. Analyses of expectancy data revealed that only with good skills did…

  13. Self-induced polarization tracking, tunneling effect and modal attraction in optical fiber

    CERN Document Server

    Guasoni, Massimiliano; Bony, Pierre-Yves; Wabnitz, Stefan; Fatome, Julien

    2015-01-01

    In this paper, we report the observation and exploitation of the capability of light to self-organize its state-of-polarization, upon propagation in optical fibers, by means of a device called Omnipolarizer. The principle of operation of this system consists in a counter-propagating four-wave mixing interaction between an incident signal and its backward replica generated at the fiber output thanks to a reflective fiber loop. We have exploited this self-induced polarization tracking phenomenon for all-optical data processing and successfully demonstrated the spontaneous repolarization of a 40-Gbit/s On-Off keying optical signal without noticeable impairments. Moreover, the strong local coupling between the two counter-propagating waves has also revealed a fascinating aspect of the Omnipolarizer called polarization-based tunneling effect. This intrinsic property enables us to instantaneously let jump a polarization information onto the reflected signal, long before the expected time-of-flight induced by the ro...

  14. [INVITED] Self-induced polarization tracking, tunneling effect and modal attraction in optical fiber

    Science.gov (United States)

    Guasoni, M.; Morin, P.; Bony, P.-Y.; Wabnitz, S.; Fatome, J.

    2016-06-01

    In this paper, we report the observation and exploitation of the capability of light to self-organize its state-of-polarization, upon propagation in optical fibers, by means of a device called Omnipolarizer. The principle of operation of this system consists in a counter-propagating four-wave mixing interaction between an incident signal and its backward replica generated at the fiber output thanks to a reflective fiber loop. We have exploited this self-induced polarization tracking phenomenon for all-optical data processing and successfully demonstrated the spontaneous repolarization of a 40-Gbit/s On-Off keying optical signal without noticeable impairments. Moreover, the strong local coupling between the two counter-propagating waves has also revealed a fascinating aspect of the Omnipolarizer called polarization-based tunneling effect. This intrinsic property enables us to instantaneously let "jump" a polarization information onto the reflected signal, long before the expected time-of-flight induced by the round-trip along the fiber span. Finally, we discuss how the concept of self-organization could be generalized to multimode fibers, which paves the way to new important applications in the framework of spatial-mode-multiplexing.

  15. Surveys for Stenoma catenifer (Lepidoptera: Elachistidae) and associated parasitoids infesting avocados in Perú.

    Science.gov (United States)

    Hoddle, Mark S; Hoddle, Christina D

    2012-04-01

    Surveys for Stenoma catenifer Walsingham, the avocado seed moth, and its associated larval parasitoids were conducted in the Departments of Junín, Huánuco, Cusco, and Madre de Dios in Perú. Fruit infestation levels in some areas ranged from 0 to 58%, and parasitism of S. catenifer larvae in Junín and Huánuco was 23%. Five species of hymenopteran parasitoid in two families, Braconidae (Apanteles sp., Hypomicrogaster sp., and Chelonus sp.) and Ichneumonidae (Pristeromerus sp. and Xiphosomella sp.), were reared from larvae, and one species of tachinid fly (Chrysodoria sp.) emerged from pupae. The dominant larval parasitoid, a gregarious Apanteles sp., accounted for 55% of parasitized hosts. Branch and twig tunneling by S. catenifer larvae in a commercial Hass avocado orchard was observed in Cusco. The field attractiveness of the sex pheromone of S. catenifer was demonstrated with 73% of monitoring traps deployed in three departments (Junín, Huánuco, and Cusco) catching male moths. Approximately 55% of avocado fruit sourced from the Province of Chanchamayo (Junin) and purchased at the Mercado Modelo de Frutas in La Victoria, in central Lima were infested with larvae of S. catenifer. Infested avocado fruit sold at this market could represent a potential incursion threat to coastal Hass avocado production regions in Perú that are reportedly free of this pest. PMID:22606810

  16. Does host plant influence parasitism and parasitoid species composition in Lygus rugulipennis? A molecular approach.

    Science.gov (United States)

    Gariepy, T D; Kuhlmann, U; Gillott, C; Erlandson, M

    2008-06-01

    Lygus Hahn plant bugs (Hemiptera: Miridae) are serious pests of a wide variety of economically important crops in North America. European Peristenus digoneutis Loan and P. relictus Ruthe (Hymenoptera: Braconidae) are being considered for release in Canada as part of a classical biological control program for Lygus. The attractiveness of different host plants to European Peristenus has not been addressed, but may be an important consideration prior to parasitoid release. Lygus rugulipennis Poppius nymphs were collected in the Northern Temperate Atlantic (NTA) ecoregion on red clover (Trifolium pratense L.; Fabaceae) and chamomile (Matricaria recutita L.; Asteraceae), and in the Western European Broadleaf Forest (WEBF) ecoregion on red clover and alfalfa (Medicago sativa L.; Fabaceae). Parasitism levels and parasitoid species were determined using a multiplex PCR assay for P. digoneutis, P. relictus, and P. pallipes Curtis. Mean parasitism levels in L. rugulipennis were 45-49% in the NTA ecoregion and 25-32% in the WEBF ecoregion. However, in neither ecoregion were parasitism levels and parasitoid species compositions significantly different in nymphs from different host plant species. Furthermore, multiparasitism was low despite the fact that P. digoneutis and P. relictus share the same host species. PMID:18439339

  17. Attraction between two similar particles in an electrolyte: effects of Stern layer absorption

    Directory of Open Access Journals (Sweden)

    Franck Plouraboué

    2010-03-01

    Full Text Available When Debye length is comparable or larger than the distance between two identical particles, the overlapping among the particles double-layers can play an important role in their interactions. This paper presents a theoretical analysis of the interaction among two identical particles with overlapped double-layers. We particularly focus on the effect of a Stern electro static condition from linearization of the adsorption isotherm near the isoelectric (neutrality point in order to capture how polyvalent ion condensation affect sand reverses the surface charge. The stationary potential problem is solved within the framework of an asymptotic lubrication approach for a mean-field Poisson-Boltzmann model. Both spherical and cylindrical particles are analyzed. The results are finally discussed in the context of Debye-Hückel (D-H limit and beyond it.Quando o comprimento de Debye é comparável ou maior do que as distâncias entre duas partículas idênticas, a interseção entre as duplas camadas pode desempenhar papel importante na interação entre elas. Este artigo apresenta uma análise teórica da interação entre duas partículas idênticas as quais apresentam interseção entre as camadas duplas. Nós particularmente focamos a análise sobre o efeito da condição eletrostática de Stern a partir da linearização da isoterma de adsorção perto do ponto isoelétrico para capturar como a condensação do íon polivalente afeta e reverte a densidade de carga superficial. O problema que governa o potencial estacionário é resolvido no contexto de uma teoria assintótica de lubrificação para o modelo de Poisson-Boltzmann. O modelo é analisado para partículas cilíndricas e esféricas. Os resultados são finalmente discutidos no contexto do limite de Debye-Hückel e além dele.

  18. Judging attractiveness: Biases due to raters’ own attractiveness and intelligence

    Directory of Open Access Journals (Sweden)

    Stacy Yen-Lin Sim

    2015-12-01

    Full Text Available Tennis and Dabbs (1975 reported that physically attractive males showed a positivity bias when rating the attractiveness of others. The opposite pattern was observed for females. We attempted to replicate and extend these findings by: (1 using self-assessed attractiveness rather than the experimentally derived attractiveness measure used in previous research, (2 using face-to-face interactions with targets as opposed to using photographs, and (3 examining the effect of another ego-involving attribute: intelligence. Consistent with previous research, attractiveness judgments made by men, but not women, correlated positively with their own self-perceived level of attractiveness (r = .51, p < .001. Attractiveness judgments made by women, but not men, correlated negatively with their intelligence (r = −.32, p = .001. Judgments of attractiveness are thus biased by a rater’s own attributes (e.g. attractiveness and intelligence, but these effects are not generalizable across men and women raters, and may be driven by different mechanisms.

  19. An endoparasitoid Cretaceous fly and the evolution of parasitoidism

    Science.gov (United States)

    Zhang, Qingqing; Zhang, Junfeng; Feng, Yitao; Zhang, Haichun; Wang, Bo

    2016-02-01

    Parasitoidism is a key innovation in insect evolution, and parasitoid insects, nowadays, play a significant role in structuring ecological communities. Despite their diversity and ecological impact, little is known about the early evolution and ecology of parasitoid insects, especially parasitoid true flies (Diptera). Here, we describe a bizarre fly, Zhenia xiai gen. et sp. nov., from Late Cretaceous Burmese amber (about 99 million years old) that represents the latest occurrence of the family Eremochaetidae. Z. xiai is an endoparasitoid insect as evidenced by a highly developed, hypodermic-like ovipositor formed by abdominal tergites VIII + IX that was used for injecting eggs into hosts and enlarged tridactylous claws supposedly for clasping hosts. Our results suggest that eremochaetids are among the earliest definite records of parasitoid insects. Our findings reveal an unexpected morphological specialization of flies and broaden our understanding of the evolution and diversity of ancient parasitoid insects.

  20. Old maids have more appeal: effects of age and pheromone source on mate attraction in an orb-web spider

    OpenAIRE

    Cory, Anna-Lena; Schneider, Jutta M

    2016-01-01

    Background. In many insects and spider species, females attract males with volatile sex pheromones, but we know surprisingly little about the costs and benefits of female pheromone emission. Here, we test the hypothesis that mate attraction by females is dynamic and strategic in the sense that investment in mate attraction is matched to the needs of the female. We use the orb-web spider Argiope bruennichi in which females risk the production of unfertilised egg clutches if they do not receive...

  1. Diversity of parasitoid Lepidopterans larvae on Brassicaceae in West Sumatra

    OpenAIRE

    FENI YUSMARIKA; YAHERWANDI; RUSDI RUSLI; NOVRI NELLY

    2010-01-01

    Nelly N, Rusli R, Yaherwandi, Yusmarika F (2010) Diversity of parasitoid Lepidopterans larvae on Brassicaceae. Biodiversitas 11: 93-96. Diversity of parasitoid lepidopterans larvae on Brassicaceae was conducted in several Brassicaceae areas in West Sumatra. The objective of the research was to study the diversity of parasitoid lepidopterans larvae on Brassicaceae. Sampling was conducted on Brassicaceae plants: cabbage, cauliflower, petsai and sawi. It was taken five samples in every plot, by ...

  2. Chemical Control for Host-Parasitoid Model within the Parasitism Season and Its Complex Dynamics

    Directory of Open Access Journals (Sweden)

    Tao Wang

    2016-01-01

    Full Text Available In the present paper, we develop a host-parasitoid model with Holling type II functional response function and chemical control, which can be applied at any time of each parasitism season or pest generation, and focus on addressing the importance of the timing of application pesticide during the parasitism season or pest generation in successful pest control. Firstly, the existence and stability of both the host and parasitoid populations extinction equilibrium and parasitoid-free equilibrium have been investigated. Secondly, the effects of key parameters on the threshold conditions have been discussed in more detail, which shows the importance of pesticide application times on the pest control. Thirdly, the complex dynamics including multiple attractors coexistence, chaotic behavior, and initial sensitivity have been studied by using numerical bifurcation analyses. Finally, the uncertainty and sensitivity of all the parameters on the solutions of both the host and parasitoid populations are investigated, which can help us to determine the key parameters in designing the pest control strategy. The present research can help us to further understand the importance of timings of pesticide application in the pest control and to improve the classical chemical control and to make management decisions.

  3. Effects of Bt plants on the development and survival of the parasitoid Cotesia plutellae (Hymenoptera: Braconidae) in susceptible and Bt-resistant larvae of the diamondback moth, Plutella xylostella (Lepidoptera: Plutellidae).

    Science.gov (United States)

    Schuler, Tanja H; Denholm, Ian; Clark, Suzanne J; Stewart, C Neal; Poppy, Guy M

    2004-05-01

    A range of crops have been transformed with delta-endotoxin genes from Bacillus thuringiensis (Bt) to produce transgenic plants with high levels of resistance to lepidopteran pests. Parasitoids are important natural enemies of lepidopteran larvae and the effects of Bt plants on these non-target insects have to be investigated to avoid unnecessary disruption of biological control. This study investigated the effects of Cry1Ac-expressing transgenic oilseed rape (Brassica napus) on the solitary braconid endoparasitoid Cotesia plutellae in small-scale laboratory experiments. C. plutellae is an important natural enemy of the diamondback moth (Plutella xylostella), the most important pest of brassica crops world-wide. Bt oilseed rape caused 100% mortality of a Bt-susceptible P. xylostella strain but no mortality of the Bt-resistant P. xylostella strain NO-QA. C. plutellae eggs laid in Bt-susceptible hosts feeding on Bt leaves hatched but premature host mortality did not allow C. plutellae larvae to complete their development. In contrast, C. plutellae developed to maturity in Bt-resistant hosts fed on Bt oilseed rape leaves and there was no effect of Bt plants on percentage parasitism, time to emergence from hosts, time to adult emergence and percentage adult emergence from cocoons. Weights of female progeny after development in Bt-resistant hosts did not differ between plant types but male progeny was significantly heavier on wildtype plants in one of two experiments. The proportion of female progeny was significantly higher on Bt plants in the first experiment with Bt-resistant hosts but this effect was not observed again when the experiment was repeated. PMID:15121457

  4. The Effects of Attitude Similarity and Utility on Liking for a Stranger: Measurement of Attraction with the IJS.

    Science.gov (United States)

    Nesler, Mitchell S.; And Others

    Research has demonstrated that attraction to a stranger is a function of the proportion of similar attitudes reported by that stranger. Traditional theories of attraction do not usually differentiate between respect or esteem for another and liking. This study used a 2 x 2 factorial experiment to test the hypothesis that the desire to work with…

  5. Old maids have more appeal: effects of age and pheromone source on mate attraction in an orb-web spider.

    Science.gov (United States)

    Cory, Anna-Lena; Schneider, Jutta M

    2016-01-01

    Background. In many insects and spider species, females attract males with volatile sex pheromones, but we know surprisingly little about the costs and benefits of female pheromone emission. Here, we test the hypothesis that mate attraction by females is dynamic and strategic in the sense that investment in mate attraction is matched to the needs of the female. We use the orb-web spider Argiope bruennichi in which females risk the production of unfertilised egg clutches if they do not receive a copulation within a certain time-frame. Methods. We designed field experiments to compare mate attraction by recently matured (young) females with females close to oviposition (old). In addition, we experimentally separated the potential sources of pheromone transmission, namely the female body and the web silk. Results. In accordance with the hypothesis of strategic pheromone production, the probability of mate attraction and the number of males attracted differed between age classes. While the bodies and webs of young females were hardly found by males, the majority of old females attracted up to two males within two hours. Old females not only increased pheromone emission from their bodies but also from their webs. Capture webs alone spun by old females were significantly more efficient in attracting males than webs of younger females. Discussion. Our results suggest that females modulate their investment in signalling according to the risk of remaining unmated and that they thereby economize on the costs associated with pheromone production and emission. PMID:27114864

  6. Drought and root herbivory interact to alter the response of above-ground parasitoids to aphid infested plants and associated plant volatile signals

    OpenAIRE

    Muhammad Tariq; Wright, Denis J.; Bruce, Toby J. A.; Staley, Joanna T.

    2013-01-01

    Multitrophic interactions are likely to be altered by climate change but there is little empirical evidence relating the responses of herbivores and parasitoids to abiotic factors. Here we investigated the effects of drought on an above/below-ground system comprising a generalist and a specialist aphid species (foliar herbivores), their parasitoids, and a dipteran species (root herbivore).We tested the hypotheses that: (1) high levels of drought stress and below-ground herbivory interact to r...

  7. Out of Lust or Jealousy: The Effects of Mate-Related Motives on Study-Time Allocation to Faces Varying in Attractiveness.

    Directory of Open Access Journals (Sweden)

    Weijian Li

    Full Text Available Although a growing number of empirical studies have revealed that activating mate-related motives might exert a specific set of consequences for human cognition and behaviors, such as attention and memory, little is known about whether mate-related motives affect self-regulated learning. The present study examined the effects of mate-related motives (mate-search and mate-guarding on study-time allocation to faces varying in attractiveness. In two experiments, participants in mate-related priming conditions (Experiment 1: mate-search; Experiment 2: mate-guarding or control conditions studied 20 female faces (10 highly attractive, 10 less attractive during a self-paced study task, and then were given a yes/no face recognition task. The finding of Experiment 1 showed that activating a mate-search motive led the male participants to allocate more time to highly attractive female faces (i.e., perceived potential mates than to less attractive ones. In Experiment 2, female participants in the mate-guarding priming condition spent more time studying highly attractive female faces (i.e., perceived potential rivals than less attractive ones, compared to participants in the control condition. These findings illustrate the highly specific consequences of mate-related motives on study-time allocation, and highlight the value of exploring human cognition and motivation within evolutionary and self-regulated learning frameworks.

  8. Out of Lust or Jealousy: The Effects of Mate-Related Motives on Study-Time Allocation to Faces Varying in Attractiveness.

    Science.gov (United States)

    Li, Weijian; Zhang, Yuchi; Li, Fengying; Li, Xinyu; Li, Ping; Jia, Xiaoyu; Chen, Haide; Ji, Haojie

    2015-01-01

    Although a growing number of empirical studies have revealed that activating mate-related motives might exert a specific set of consequences for human cognition and behaviors, such as attention and memory, little is known about whether mate-related motives affect self-regulated learning. The present study examined the effects of mate-related motives (mate-search and mate-guarding) on study-time allocation to faces varying in attractiveness. In two experiments, participants in mate-related priming conditions (Experiment 1: mate-search; Experiment 2: mate-guarding) or control conditions studied 20 female faces (10 highly attractive, 10 less attractive) during a self-paced study task, and then were given a yes/no face recognition task. The finding of Experiment 1 showed that activating a mate-search motive led the male participants to allocate more time to highly attractive female faces (i.e., perceived potential mates) than to less attractive ones. In Experiment 2, female participants in the mate-guarding priming condition spent more time studying highly attractive female faces (i.e., perceived potential rivals) than less attractive ones, compared to participants in the control condition. These findings illustrate the highly specific consequences of mate-related motives on study-time allocation, and highlight the value of exploring human cognition and motivation within evolutionary and self-regulated learning frameworks. PMID:26121131

  9. Employer attractiveness of the Swedish Armed Forces : A quantitative study of gender differences and the effects of employer brand attributes and social media in the government authority sector

    OpenAIRE

    Jorlöv, Karin; Venngren, Emma

    2014-01-01

    The main purpose of this degree project has been to examine the effects of employer brand attributes and activities on social media to the employer attractiveness of the Swedish Armed Forces. We aimed to make theoretical contributions to the fields of employer branding and social media marketing, and test a unique conceptual model for the government authority. The conceptual model focuses on employer brand attributes that have previously been connected to employer attractiveness in this type ...

  10. Displacement of Aphytis chrysomphali by Aphytis melinus, parasitoids of the California red scale, in the Iberian Peninsula

    Directory of Open Access Journals (Sweden)

    Juan Ramon Boyero

    2014-02-01

    Full Text Available Parasitoids are the main natural enemies of the California red scale, Aonidiella aurantii (Maskell and on occasion can regulate their populations. To increase their effectiveness, inoculative or augmentative releases of parasitoids are promoted. Previous to the implementation of any release strategy an important and necessary step is to acquire knowledge on the parasitoid fauna associated with this key phytophagous pest. Parasitoids were surveyed and quantified in Spanish citrus orchards between 2005 and 2009. Aphytis melinus DeBach (87.1% resulted as the dominant species, followed by Aphytis chrysomphali (Mercet (15.9%, Encarsia perniciosi (Tower (2.4% and Aphycus hederaceus (Westwood (0.004%. Overall, higher levels of parasitism were recorded in fruit than in twigs. Scales in fruit were parasitized at similar levels by the different parasitoid species whereas E. perniciosi was more active in twigs. Data eventually reveal the recent displacement of A. chrysomphali by A. melinus. The implications of these results on the biological control of A. aurantii are discussed and this information will be useful in the decision of IPM strategies for this pest.

  11. Attack and Success of Native and Exotic Parasitoids on Eggs of Halyomorpha halys in Three Maryland Habitats.

    Science.gov (United States)

    Herlihy, Megan V; Talamas, Elijah J; Weber, Donald C

    2016-01-01

    Egg parasitoids of the exotic invasive brown marmorated stink bug, Halyomorpha halys (Stål), were investigated using lab-reared fresh (live) and frozen (killed) lab-reared sentinel egg masses deployed for 72h on foliage in three habitats-woods, orchard, and soybean field-in Maryland, USA, in summer 2014. Four native hymenopteran species, Telenomus podisi Ashmead (Scelionidae), Trissolcus euschisti (Ashmead) and Tr. brochymenae Ashmead (Scelionidae), and Anastatus reduvii (Howard) (Eupelmidae), developed and emerged from H. halys eggs. One exotic parasitoid, Trissolcus japonicus (Ashmead), emerged, providing the first known occurrence of this species in North America. Native parasitoids emerged from frozen eggs significantly more often than from fresh eggs (89.3% of egg masses and 98.1% of individual eggs), whereas the exotic Tr. japonicus did not show a similar difference, strongly suggesting adaptation to H. halys as a host by Tr. japonicus but not by the native species. Parasitoids were habitat-specific: all three Trissolcus species were significantly more likely to occur in the woods habitat, whereas Te. podisi was found exclusively in the soybean field. Further investigations are required to elucidate evolving host-parasitoid relationships, habitat specificity, and non-target effects of Tr. japonicus over the expanded range of H. halys in North America. PMID:26983012

  12. Qualitative analysis of aphid and primary parasitoid trophic relations of genus Alloxysta (Hymenoptera: Cynipoidea: Figitidae: Charipinae).

    Science.gov (United States)

    Ferrer-Suay, Mar; Janković, Marina; Selfa, Jesús; Van Veen, F J Frank; Tomanović, Željko; Kos, Katarina; Rakhshani, Ehsan; Pujade-Villar, Juli

    2014-12-01

    Charipinae hyperparasitoids affect effectiveness of the primary parasitoids of aphids by decreasing their abundance and modifying their behavior. As a result, increase of aphid populations can cause severe yield losses in some crops. Therefore, ecological studies on the subfamily Charipinae have a great economical and biological importance. Host specificity of these hyperparasitoids is still under debate and for many Charipinae species very little is known about their trophic relations. Here, we give a comprehensive overview of the trophic relationships between the Charipinae species of the genus Alloxysta Förster and their aphid and primary parasitoids hosts, worldwide. Within this subfamily, Alloxysta arcuata (Kieffer), Alloxysta brevis (Thomson), Alloxysta fuscicornis (Hartig), and Alloxysta victrix (Westwood) are the most generalist species sharing many aphid hosts, while for primary parasitoid hosts these are A. arcuata, A. brevis, Alloxysta pleuralis (Cameron), and A. victrix. Alloxysta citripes (Thomson), Alloxysta halterata (Thomson), Alloxysta leunisii (Hartig), and Alloxysta ramulifera (Thomson) appear, up to now, as the most specialized in relation to the primary parasitoid hosts. Primary parasitoids of the genera Aphidius Nees, Lysiphlebus Förster, Praon Haliday, and Trioxys Haliday are the most common hosts for Alloxysta species, and the common host aphid species belong to the genera Aphis L., Uroleucon Mordvilko, Myzus Passerini, and Sitobion Mordvilko. Host range is analyzed for each Alloxysta species, as well as the extent of overlap between them. We used Jaccard's distance and a hierarchical cluster analysis to determine the host range dissimilarity. A permutation test has been applied to analyze if the host range dissimilarity is significantly different from what is expected by chance. We have calculated additional qualitative measures that complement well the Alloxysta niche overlap analysis and evaluated their host specificity using different

  13. Utilisation of the egg-larval parasitoid, Fopius (Biosteres) arisanus, for augmentative biological control of tephritid fruit flies

    International Nuclear Information System (INIS)

    more. The countries supplying the insects could ask for payment for use of their natural resources. In some situations, there is strong opposition to parasitoid introductions from the lay and scientific communities due to the argument that introduced parasitoids could have adverse effects on beneficial insects which control weeds. When new introductions are successful, they must be evaluated in quarantine for months before they can be released into the field. There is no guarantee that new parasitoid species will find a niche in the tephritid fruit fly infested areas for competing well against the existing parasitoid species. A strategy which we believe has been neglected is laboratory colonisation, mass rearing and augmentative release of F. arisanus, the parasitoid species which has proved to be most successful in the Hawaiian ecosystem. We envisioned that successful colonisation of F. arisanus could provide the insight and know-how for developing different strains of F. arisanus for different fruit fly species. This strategy would complement and support foreign explorations for tephritid fruit fly parasitoids. We describe how F. arisanus is colonised, explain the research developments leading to mass production and outline what we believe can be done to develop new strains of F. arisanus

  14. Parasitoid foraging behaviour in a competitive environment

    OpenAIRE

    Couchoux, Christelle

    2013-01-01

    In my thesis I investigated the foraging behaviour of the wasp Hyposoter horticola, an egg-larval parasitoid of the Glanville fritillary butterfly Melitaea cinxia, in the Åland islands in Finland. The particularity of this system is that the wasp is resource limited and faces strong intraspecific competition. ---------- I first focused on behaviour at an individual scale. In a series of experiments I tested how H. horticola s host searching behaviour was affected by developmental timing of b...

  15. Rheology of Attractive Emulsions

    OpenAIRE

    Datta, Sujit S.; Gerrard, Dustin D.; Rhodes, Travers S.; Mason, Thomas G.; Weitz, David A.

    2012-01-01

    We show how attractive interactions dramatically influence emulsion rheology. Unlike the repulsive case, attractive emulsions below random close packing, RCP, can form soft gel-like elastic solids. However, above RCP, attractive and repulsive emulsions have similar elasticities. Such compressed attractive emulsions undergo an additional shear-driven relaxation process during yielding. Our results suggest that attractive emulsions begin to yield at weak points through the breakage of bonds, an...

  16. Estimating parasitoid immature mortality by comparing oviposition and pupal development of Trichogramma galloi ZUCCHI and T. pretiosum RILEY on natural and factitious hosts

    Directory of Open Access Journals (Sweden)

    CÔNSOLI F. L.

    2000-01-01

    Full Text Available Mortality during the immature development of T. galloi and T. pretiosum was estimated on UV-killed and live eggs of a factitious and a natural host, respectively. A staining technique was used to determine the actual parasitization of UV-treated eggs and was compared with the number of parasitoids that emerged per host egg (detectable parasitization. Effects of temperature as a factor of mortality during the immature development of both parasitoids on the factitious host was also assessed. The actual and detectable parasitization of live hosts was measured by recording both the parasitization behavior and the number of eggs where a parasitoid developed successfully. Our data show that mortality during immature development of both parasitoids may occur in live eggs of the natural host. No such mortality was observed when parasitoids developed on UV-killed eggs of the factitious host. Possible causes of parasitoid immature mortality and the effects of using UV-treated eggs of factitious hosts in estimating the parasitism capacity of Trichogramma in field conditions are discussed.

  17. Allomonal effect of breath contributes to differential attractiveness of humans to the African malaria vector Anopheles gambiae

    NARCIS (Netherlands)

    Mukabana, W.R.; Takken, W.; Killeen, G.F.; Knols, B.G.J.

    2004-01-01

    Background - Removal of exhaled air from total body emanations or artificially standardising carbon dioxide (CO2) outputs has previously been shown to eliminate differential attractiveness of humans to certain blackfly (Simuliidae) and mosquito (Culicidae) species. Whether or not breath contributes

  18. Allomonal effect of breath contributes to differential attractiveness of humans to the African malaria vector Anopheles gambiae

    Directory of Open Access Journals (Sweden)

    Takken Willem

    2004-01-01

    Full Text Available Abstract Background Removal of exhaled air from total body emanations or artificially standardising carbon dioxide (CO2 outputs has previously been shown to eliminate differential attractiveness of humans to certain blackfly (Simuliidae and mosquito (Culicidae species. Whether or not breath contributes to between-person differences in relative attractiveness to the highly anthropophilic malaria vector Anopheles gambiae sensu stricto remains unknown and was the focus of the present study. Methods The contribution to and possible interaction of breath (BR and body odours (BO in the attraction of An. gambiae s.s. to humans was investigated by conducting dual choice tests using a recently developed olfactometer. Either one or two human subjects were used as bait. The single person experiments compared the attractiveness of a person's BR versus that person's BO or a control (empty tent with no odour. His BO and total emanations (TE = BR+BO were also compared with a control. The two-person experiments compared the relative attractiveness of their TE, BO or BR, and the TE of each person against the BO of the other. Results Experiments with one human subject (P1 as bait found that his BO and TE collected more mosquitoes than the control (P = 0.005 and P 1 attracted more mosquitoes than that of another person designated P8 (P 8 attracted more mosquitoes than the BR of P1 (P = 0.001. The attractiveness of the BO of P1 versus the BO of P8 did not differ (P = 0.346. The BO from either individual was consistently more attractive than the TE from the other (P Conclusions We demonstrated for the first time that human breath, although known to contain semiochemicals that elicit behavioural and/or electrophysiological responses (CO2, ammonia, fatty acids in An. gambiae also contains one or more constituents with allomonal (~repellent properties, which inhibit attraction and may serve as an important contributor to between-person differences in the relative

  19. The Undermining Effect of Facial Attractiveness on Brain Responses to Fairness in Ultimatum Game: An ERP Study

    OpenAIRE

    Qingguo eMa; Yue eHu; Shushu eJiang; Liang eMeng

    2015-01-01

    To investigate the time course of the neural processing of facial attractiveness and its influence on fairness consideration during social interactions, event-related potentials (ERP) were recorded from 21 male subjects performing a two-person Ultimatum Game (UG). During this bargaining game, the male subjects played responders who decided whether to accept offers from female proposers, whose facial images (grouped as attractive and unattractive) were presented prior to the offer presentation...

  20. Five new associations of parasitoids in potter wasps (Vespidae, Eumeninae

    Directory of Open Access Journals (Sweden)

    Tiago H. Auko

    2014-12-01

    Full Text Available Five new associations of parasitoids in potter wasps (Vespidae, Eumeninae. New associations of host and parasitoids involving potter wasps: Toxophora leucon and Pleurochrysis sp. were found parasitizing Cyphomenes anisitsii, Chrysis sp. (gr. intricans was found parasitizing Minixi suffusum, Plega beardi was found parasitizing Montezumia pelagica sepulchralis and Macrosiagon sp. was found parasitizing Pachodynerus nasidens.

  1. Repellent and Attractive Effects of α-, β-, and Dihydro-β- Ionone to Generalist and Specialist Herbivores.

    Science.gov (United States)

    Cáceres, L A; Lakshminarayan, S; Yeung, K K-C; McGarvey, B D; Hannoufa, A; Sumarah, M W; Benitez, X; Scott, I M

    2016-02-01

    In plants, the oxidative cleavage of carotenoid substrates produces volatile apocarotenoids, including α-ionone, β-ionone, and dihydro-β-ionone, compounds that are important in herbivore-plant communication. For example, β-ionone is part of an induced defense in canola, Brassica napus, and is released following wounding by herbivores. The objectives of the research were to evaluate whether these volatile compounds would: 1) be released in higher quantities from plants through the over-expression of the carotenoid cleavage dioxygenase1 (CCD1) gene and 2) cause herbivores to be repelled or attracted to over-expressing plants relative to the wild-type. In vivo dynamic headspace collection of volatiles coupled with gas chromatography-mass spectrometry was used to determine volatile organic compounds (VOC) in the headspace of the Arabidopsis thaliana ecotype Columbia-0 (L.) over-expressing the AtCCD1 gene. The analytical method allowed the detection of β-ionone in the Arabidopsis headspace where emission rates ranged between 2 and 5-fold higher compared to the wild type, thus corroborating the in vivo enhancement of gene expression. A two chamber choice test between wild type and AtCCD1 plants revealed that crucifer flea beetle Phyllotreta cruciferae (Goeze) adults were repelled by the AtCCD1 plants with the highest transcription and β-ionone levels. α-Ionone and dihydro-β-ionone were not found in the headspace analysis, but solutions of the three compounds were tested in the concentration range of β-ionone found in the Arabidopsis headspace (0.05 to 0.5 ng/μl) in order to assess their biological activity with crucifer flea beetle, two spotted spider mite Tetranychus urticae (Koch), and silverleaf whiteflies Bemisia tabaci (Gennadius). Choice bioassays demonstrated that β-ionone has a strong repellent effect toward both the flea beetle and the spider mite, and significant oviposition deterrence to whiteflies. In contrast, dihydro-β-ionone had attractant

  2. Web-based recruitment: effects of information, organizational brand, and attitudes toward a Web site on applicant attraction.

    Science.gov (United States)

    Allen, David G; Mahto, Raj V; Otondo, Robert F

    2007-11-01

    Recruitment theory and research show that objective characteristics, subjective considerations, and critical contact send signals to prospective applicants about the organization and available opportunities. In the generating applicants phase of recruitment, critical contact may consist largely of interactions with recruitment sources (e.g., newspaper ads, job fairs, organization Web sites); however, research has yet to fully address how all 3 types of signaling mechanisms influence early job pursuit decisions in the context of organizational recruitment Web sites. Results based on data from 814 student participants searching actual organization Web sites support and extend signaling and brand equity theories by showing that job information (directly) and organization information (indirectly) are related to intentions to pursue employment when a priori perceptions of image are controlled. A priori organization image is related to pursuit intentions when subsequent information search is controlled, but organization familiarity is not, and attitudes about a recruitment source also influence attraction and partially mediate the effects of organization information. Theoretical and practical implications for recruitment are discussed. PMID:18020806

  3. What Is the Relationship between the Age of the Audience and the Effectiveness of Marketing Techniques in Attracting Students to a Community College?

    Science.gov (United States)

    Silberg, Carol A.

    A study was conducted at Prince George's Community College (PGCC) to investigate the relationship between the age of the audience and the effectiveness of marketing techniques in attracting students to the college. The study focused on how and why community colleges market themselves, and why some techniques were more effective than others for…

  4. Mutually beneficial host exploitation and ultra-biased sex ratios in quasisocial parasitoids.

    Science.gov (United States)

    Tang, Xiuyun; Meng, Ling; Kapranas, Apostolos; Xu, Fuyuan; Hardy, Ian C W; Li, Baoping

    2014-01-01

    Selfish interests usually preclude resource sharing, but under some conditions collective actions enhance per capita gains. Such Allee effects underlay early explanations of social evolution but current understanding focusses on kin selection (inclusive fitness). We find an Allee effect that explains unusual quasisociality (cooperative brood care) among parasitoid wasps without invoking or precluding kin selection effects. In Sclerodermus harmandi, individual females produce most offspring when exploiting small hosts alone. However, larger hosts are more successfully exploited by larger groups of females, with the per-female benefits outweighing the costs of host sharing. Further, the extremely biased sex ratios (97% female) are better explained by mutually beneficial female-female interactions that increase the reproductive value of daughters (local resource enhancement), rather than by the usually invoked local mate competition between males. Thus, atypical quasisocial behaviour in a parasitoid wasp directly enhances reproductive success and selects for very extremely female-biased sex ratios. PMID:25216091

  5. Euclidean gravity attracts

    OpenAIRE

    Bakker MR; Smit, J.

    1993-01-01

    We look at gravitational attraction in simplicial gravity using the dynamical triangulation method. On the dynamical triangulation configurations we measure quenched propagators of a free massive scalar field. The masses measured from these propagators show that gravitational attraction is present.

  6. Resource Provisioning as a Habitat Manipulation Tactic to Enhance the Aphid Parasitoid, Aphidius colemani Viereck (Hymenoptera: Braconidae: Aphidiinae), and the Plant-Mediated Effects of a Systemic Insecticide, Imidacloprid

    OpenAIRE

    Charles-Tollerup, Jennifer Jean

    2012-01-01

    Resource provisioning as a habitat manipulation tactic to control the melon aphid, Aphis gossypii, by the polyphagous aphid parasitoid, Aphidius colemani, was investigated in the ornamental, potted-plant nursery using the shrub Photinia x fraseri as a plant host. Floral food resources from an invasive, Conium maculatum, an ornamental, P. x fraseri, and a native, Salvia apiana considerably improved the longevity and fecundity of A. colemani in laboratory experiments. Additionally, floral nec...

  7. The Effect Of Intellectual Capital On Job Satisf action And Organizational Attractiveness During The Person - Organization Fit: A Case Study Of A University Hospital

    Directory of Open Access Journals (Sweden)

    Orhan Adıgüzel

    2015-12-01

    Full Text Available Basic purpose of this study is about investigating the effects of intellectual capital on job satisfaction and organizational attractiveness during the person-organization fit on employees of university hospital. For this purpose; questi on form, which created with personal information form, job satisfaction scale, organizational attractiveness scale, capital perception scale and person-organization fit scale, was applied on 330 persons, who work for university hospital. The statistical technics was used for testing the hypotheses, which were created for this study; “Pearson Correlation Analysis Linear” and “Multivariate Regression Models”. The results of study put forward that the intellectual capital structure of health establishment is effective on health employees to get job satisfaction and to find their establishment as attractive.

  8. Molecular analysis reveals high compartmentalization in aphid-primary parasitoid networks and low parasitoid sharing between crop and noncrop habitats.

    Science.gov (United States)

    Derocles, Stephane A P; Le Ralec, Anne; Besson, Mathilde M; Maret, Marion; Walton, Alan; Evans, Darren M; Plantegenest, Manuel

    2014-08-01

    The ecosystem service of insect pest regulation by natural enemies, such as primary parasitoids, may be enhanced by the presence of uncultivated, semi-natural habitats within agro-ecosystems, although quantifying such host-parasitoid interactions is difficult. Here, we use rRNA 16S gene sequencing to assess both the level of parasitism by Aphidiinae primary parasitoids and parasitoid identity on a large sample of aphids collected in cultivated and uncultivated agricultural habitats in Western France. We used these data to construct ecological networks to assess the level of compartmentalization between aphid and parasitoid food webs of cultivated and uncultivated habitats. We evaluated the extent to which uncultivated margins provided a resource for parasitoids shared between pest and nonpest aphids. We compared the observed quantitative ecological network described by our molecular approach to an empirical qualitative network based on aphid-parasitoid interactions from traditional rearing data found in the literature. We found that the molecular network was highly compartmentalized and that parasitoid sharing is relatively rare between aphids, especially between crop and noncrop compartments. Moreover, the few cases of putative shared generalist parasitoids were questionable and could be due to the lack of discrimination of cryptic species or from intraspecific host specialization. Our results suggest that apparent competition mediated by Aphidiinae parasitoids is probably rare in agricultural areas and that the contribution of field margins as a source of these biocontrol agents is much more limited than expected. Further large-scale (spatial and temporal) studies on other crops and noncrop habitats are needed to confirm this. PMID:24612360

  9. Interpersonal Congruency, Attitude Similarity, and Interpersonal Attraction

    Science.gov (United States)

    Touhey, John C.

    1975-01-01

    As no experimental study has examined the effects of congruency on attraction, the present investigation orthogonally varied attitude similarity and interpersonal congruency in order to compare the two independent variables as determinants of interpersonal attraction. (Author/RK)

  10. The Differential Effect of Skin Color on Attractiveness, Personality Evaluations, and Perceived Life Success of African Americans

    Science.gov (United States)

    Wade, T. Joel; Bielitz, Sara

    2005-01-01

    Skin color in relation to perceived attractiveness, personality ratings, and perceived life success of African Americans was investigated in a 2 (sex of participant) 2 (skin color of stimulus person) 2 (sex of stimulus person) design. Based on prior research, Skin Color Sex of Stimulus Person and Sex of Participant Skin Color interactions were…

  11. Differential attractiveness of humans to the African malaria vector Anopheles gambiae Giles - Effects of host characteristics and parasite infection

    NARCIS (Netherlands)

    Mukabana, W.R.

    2002-01-01

    The results of a series of studies designed to understand the principal factors that determine the differential attractiveness of humans to the malaria vector Anopheles gambiae are described in this thesis. Specific

  12. Chemosignalling effects of human tears revisited : Does exposure to female tears decrease males' perception of female sexual attractiveness?

    NARCIS (Netherlands)

    Gracanin, A.; van Assen, M.A.L.M.; Omrčen, Višnja; Koraj, Ivana; Vingerhoets, A.J.J.M.

    2016-01-01

    Gelstein et al. reported the results of three experiments suggesting a dampening influence of inhalation of female emotional tears on males' arousal and perception of female sexual attractiveness, specifically in non-sexual situations. This prompted the hypothesis that crying exerts its influence on

  13. Biological Control of Solenopsis Fire Ants by Pseudacteon Parasitoids: Theory and Practice

    OpenAIRE

    Morrison, Lloyd W.

    2012-01-01

    Pseudacteon parasitoids are potential biocontrol agents of invasive Solenopsis fire ants. Pseudacteon species that parasitize the invasive S. invicta Buren and S. richteri Forel have been introduced to, and naturally dispersed across, the southeastern USA, although there is no evidence yet that Solenopsis host ant populations have decreased. The ability of introduced Pseudacteon species to regulate Solenopsis populations will depend upon the relative importance of top-down effects in the reci...

  14. The role of geography and host abundance in the distribution of parasitoids of an alien pest

    OpenAIRE

    Nováková, Petra; Holuša, Jaroslav; Horák, Jakub

    2016-01-01

    Chalcid wasps (Hymenoptera: Chalcidoidea) are probably the most effective and abundant parasitoids of the horse chestnut leaf miner (Cameraria ohridella), an alien pest in Europe that lacks specialized enemies. We studied how the species richness and abundance of chalcids are influenced by altitude, direction of an alien spread and host abundance of C. ohridella. We quantified the numbers and species richness of chalcid wasps and the numbers of C. ohridella that emerged from horse chestnut (A...

  15. Age at reproductive maturity and effect of age and time of day on sex attraction in the potato psyllid Bactericera cockerelli

    Institute of Scientific and Technical Information of China (English)

    Christelle Guédot; David R.Horton; Peter J.Landolt

    2012-01-01

    The potato psyllid,Bactericera (=Paratrioza) cockerelli ((S)ulc) (Hemiptera:Triozidae),is a major pest of potato.Studies were conducted to determine the age at which both males and females reach reproductive maturity and the effect of age and time of day on sex attraction.Adult B.cockerelli reach reproductive maturity within 48 h post-eclosion,with females being mature on the day of eclosion and males at 1 day post-eclosion.Oviposition generally began 2 days after mating but was delayed when females mated within 2 days post-eclosion.In laboratory olfactometer assays,the age of females used as odor sources and the age of males assayed to these odors did not affect sex attraction,with both younger (1-4-day-old) and older (8-10-day-old) males being attracted to females,regardless of female age (1-4-day-old or 8-10-day-old).Males assayed to live females at different times during the photophase (between 8:00 and 20:00 hours) were attracted to females between 11:00 and 17:00 hours,showing a temporal periodicity in sex attraction with B.cockerelli at least during the photophase.

  16. Trichogramma parasitoids alter the metabolic physiology of Manduca eggs.

    Science.gov (United States)

    Potter, Kristen A; Woods, H Arthur

    2012-09-01

    Egg parasitoids face unique developmental constraints. First, they have exceptionally limited resources to support themselves and their siblings through three life stages. Second, they develop within the physiological system of another species, which they modify to their own ends. We examined how these constraints affect the metabolic physiology of egg parasitism, and whether parasitoids retool their host eggshell to account for their different metabolic demands. Higher-conductance eggshells allow more oxygen to reach the developing parasitoids, but also allow more water to leave the egg. We used Manduca sexta (Lepidoptera: Sphingidae) eggs and Trichogramma (Hymenoptera: Trichogrammatidae) parasitoids from southeastern AZ, USA. Compared with unparasitized Manduca eggs, eggs parasitized by Trichogramma had lower peak metabolic rates and approximately 50 per cent lower metabolic efficiency. However, developing Trichogramma were far more efficient than typical transfer efficiencies between tropic levels (approx. 10%). Even within a few hours of parasitization, eggs containing more Trichogramma had lower per-parasitoid metabolic rates, suggesting that parasitoid larvae have mechanisms for rapidly adjusting their metabolic rates based on number of siblings. Parasitoids also appear to control the conductance of their host eggshell: their different metabolic demands were mirrored by shifts in rates of water loss. PMID:22719035

  17. Temperature-dependent functional response of Spalangia cameroni (Perkins) (Hymenoptera: Pteromalidae), a parasitoid of Stomoxys calcitrans (L.) (Diptera: Muscidae)

    DEFF Research Database (Denmark)

    Skovgård, Henrik; Nachman, Gösta

    2015-01-01

    The effects of host density, temperature, and burial depths on the functional response of the synovigenic parasitoid Spalangia cameroni (Perkins) attacking pupae of the stable fly Stomoxys calcitrans (L.) were examined. Five temperatures (15, 20, 25, 30, and 35 degrees C), six host densities (2, ...

  18. Drought stress affects plant metabolites and herbivore preference but not host location by its parasitoids.

    Science.gov (United States)

    Weldegergis, Berhane T; Zhu, Feng; Poelman, Erik H; Dicke, Marcel

    2015-03-01

    One of the main abiotic stresses that strongly affects plant survival and the primary cause of crop loss around the world is drought. Drought stress leads to sequential morphological, physiological, biochemical and molecular changes that can have severe effects on plant growth, development and productivity. As a consequence of these changes, the interaction between plants and insects can be altered. Using cultivated Brassica oleracea plants, the parasitoid Microplitis mediator and its herbivorous host Mamestra brassicae, we studied the effect of drought stress on (1) the emission of plant volatile organic compounds (VOCs), (2) plant hormone titres, (3) preference and performance of the herbivore, and (4) preference of the parasitoid. Higher levels of jasmonic acid (JA) and abscisic acid (ABA) were recorded in response to herbivory, but no significant differences were observed for salicylic acid (SA) and indole-3-acetic acid (IAA). Drought significantly impacted SA level and showed a significant interactive effect with herbivory for IAA levels. A total of 55 VOCs were recorded and the difference among the treatments was influenced largely by herbivory, where the emission rate of fatty acid-derived volatiles, nitriles and (E)-4,8-dimethylnona-1,3,7-triene [(E)-DMNT] was enhanced. Mamestra brassicae moths preferred to lay eggs on drought-stressed over control plants; their offspring performed similarly on plants of both treatments. VOCs due to drought did not affect the choice of M. mediator parasitoids. Overall, our study reveals an influence of drought on plant chemistry and insect-plant interactions. PMID:25370387

  19. The Parasitoid Factor in the Virulence and Spread of Lepidopteran Baculoviruses

    Institute of Scientific and Technical Information of China (English)

    J. E. Cossentine

    2009-01-01

    Insect parasitoids and baculoviruses play important roles in the natural and strategic biological control of insects. The two parasites are frequent competitors within common hosts and much research has focused on the negative impact that baculoviral host infections have on parasitoids. This review summarizes the impacts that parasitoids may have on the virulence and spread of lepidopteran baculoviruses. By changing host behavior and development, parasitoids have been shown to decrease baculovirus virulence and productivity within parasitized baculovirus-susceptible hosts; however, studies of the tools used by hymenopteran parasitoids to overcome their hosts' immune systems, suggest that parasitoids may, in some cases, facilitate baculoviral infections in less susceptible hosts. Laboratory and field research have demonstrated that parasitoids can mechanically transmit bacuioviruses between insects, and in this way, increase the efficacy of the viruses. Instances of new, more virulent isolates of baculoviruses have been recorded from specifically parasitoid-targeted hosts suggesting other possible benefits from the transmission or activation of baculoviruses by parasitoids.

  20. Effects of pesticides used in soybean crops to the egg parasitoid Trichogramma pretiosum Efeitos dos agroquímicos utilizados na cultura da soja ao parasitóide de ovos Trichogramma pretiosum

    Directory of Open Access Journals (Sweden)

    Adeney de Freitas Bueno

    2008-09-01

    Full Text Available This research aimed to study the effects of different insecticides, herbicides and fungicides on eggs, larvae and pupae of Trichogramma pretiosum. The results showed that studied pesticides had different impact on T. pretiosum. Esfenvalerate 7.5 and spinosad 24.0 grams ha-1 were classified as harmfull (class 4 while clorfluazuron 10.0, methoxyfenozide 19.2, lactofen 165.0, fomesafen 250.0, fluazifop 125.0, glyphosate 960.0 (Gliz® and Roundup Transorb®, azoxistrobin + ciproconazol 60.0 + 24.0, azoxistrobin 50.0 and myclobutanil 125.0 grams ha-1 were chemicals classified as harmless to all imature T. pretiosum stages. All the other chemicals evaluated had different impact on T. pretiosum being classified from harmless (class 1 to harmful (class 4 varying the impact accordingly to the different parasitoid stage. Then, less noxious products should be chosen whenever possible to be used in a soybean IPM program.Este trabalho teve como objetivo estudar os efeitos de diferentes inseticidas, herbicidas e fungicidas em ovos, larvas e pupas de Trichogramma pretiosum. Os resultados mostraram que os pesticidas estudados tiveram efeitos diferentes sobre T. pretiosum. Esfenvalerato 7,5 e espinosade 24,0 gramas ha-1 foram classificados como nocivos (classe 4, enquanto que clorfluazurom 10,0, metoxifenozida 19,2, lactofem 165,0, fomesafem 250,0, fluazifope 125,0, glifosato 960,0 (Gliz® e Roundup Transorb®, azoxistrobina + ciproconazole 60,0 + 24,0, azoxistrobina 50,0 e miclobutanil 125,0 gramas ha-1 foram classificados como seletivos (classe 1 para todas as fases imaturas de T. pretiosum. Todos os demais agroquímicos avaliados tiveram diferentes efeitos em T. pretiosum, sendo classificados de seletivo (classe 1 a nocivo (classe 4, variando o impacto de acordo com as diferentes fases do parasitóide. Portanto, produtos menos nocivos aos inimigos naturais devem ser escolhidos, sempre que possível, para serem usados em um programa de MIP-soja.

  1. Impact of change in winter strategy of one parasitoid species on the diversity and function of a guild of parasitoids.

    Science.gov (United States)

    Andrade, Thiago Oliveira; Krespi, Liliane; Bonnardot, Valérie; van Baaren, Joan; Outreman, Yannick

    2016-03-01

    The rise of temperatures may enable species to increase their activities during winter periods and to occupy new areas. In winter, resource density is low for most species and an increased number of active consumers during this season may produce heightened competitive pressure. In Western France, the aphid parasitoid species Aphidius avenae Haliday has been known to adopt a winter diapausing strategy adjacent to newly sown cereal crops, until recent reports of active winter populations in cereal crops. We investigate how the addition of this species to the winter guild of parasitoids may change the structure of the aphid-parasitoid food web and the host-exploitation strategies of previously occurring parasitoids. We showed that in winter, Aphidius avenae was mostly associated with two aphid species, Sitobion avenae Fabricius and Metopolophium dirhodum Walker, while the generalist species Aphidius rhopalosiphi was restricted to the aphid species Rhopalosiphum padi L. in the presence of Aphidius avenae. Due to this new competition, winter food webs present a higher degree of compartmentalization and lower proportional similarity index values than spring ones. Parasitoid and aphid abundances responded significantly to changes in daily high temperatures, suggesting that the host-parasitoid community structure can be partly predicted by climate. This study demonstrates how a change in the winter strategy of one species of a guild can modify complex interspecific relationships in host-parasitoid systems. PMID:26558625

  2. Population genetic structure of two primary parasitoids of Spodoptera frugiperda (Lepidoptera), Chelonus insularis and Campoletis sonorensis (Hymenoptera): to what extent is the host plant important?

    Science.gov (United States)

    Jourdie, Violaine; Alvarez, Nadir; Molina-Ochoa, Jaime; Williams, Trevor; Bergvinson, David; Benrey, Betty; Turlings, Ted C J; Franck, Pierre

    2010-05-01

    Plant chemistry can strongly influence interactions between herbivores and their natural enemies, either by providing volatile compounds that serve as foraging cues for parasitoids or predators, or by affecting the quality of herbivores as hosts or prey. Through these effects plants may influence parasitoid population genetic structure. We tested for a possible specialization on specific crop plants in Chelonus insularis and Campoletis sonorensis, two primary parasitoids of the fall armyworm, Spodoptera frugiperda. Throughout Mexico, S. frugiperda larvae were collected from their main host plants, maize and sorghum and parasitoids that emerged from the larvae were used for subsequent comparison by molecular analysis. Genetic variation at eight and 11 microsatellites were respectively assayed for C. insularis and C. sonorensis to examine isolation by distance, host plant and regional effects. Kinship analyses were also performed to assess female migration among host-plants. The analyses showed considerable within population variation and revealed a significant regional effect. No effect of host plant on population structure of either of the two parasitoid species was found. Isolation by distance was observed at the individual level, but not at the population level. Kinship analyses revealed significantly more genetically related--or kin--individuals on the same plant species than on different plant species, suggesting that locally, mothers preferentially stay on the same plant species. Although the standard population genetics parameters showed no effect of plant species on population structure, the kinship analyses revealed that mothers exhibit plant species fidelity, which may speed up divergence if adaptation were to occur. PMID:20406384

  3. The undermining effect of facial attractiveness on brain responses to fairness in the Ultimatum Game: an ERP study

    OpenAIRE

    Ma, Qingguo; Hu, Yue; Jiang, Shushu; Meng, Liang

    2015-01-01

    To investigate the time course of the neural processing of facial attractiveness and its influence on fairness consideration during social interactions, event-related potentials (ERP) were recorded from 21 male subjects performing a two-person Ultimatum Game (UG). During this bargaining game, the male subjects played responders who decided whether to accept offers from female proposers, whose facial images (grouped as “attractive” and “unattractive”) were presented prior to the offer presenta...

  4. The Effect of Cues of Parental Investment on Attractiveness Ratings of Males: The Impact of Child Presence and Age

    OpenAIRE

    Went, Hannah

    2007-01-01

    According to evolutionary theories of mate choice, male parental investment is a desired characteristic of long term mates. Brase (2006) found that cues of a positive disposition towards parental investment increased males’ perceived attractiveness to females. Interacting with a child was taken to be a measure of males’ disposition towards parental investment. The present study sought to replicate and extend these findings by altering the age of the child involved. The results ...

  5. Molecular Weight Dependence of the Depletion Attraction and its Effects on the Competitive Adsorption of Lung Surfactant

    OpenAIRE

    Stenger, Patrick C.; Isbell, Stephen G.; Zasadzinski, Joseph A.

    2008-01-01

    Albumin competes with lung surfactant for the air-water interface, resulting in increased surface tension. Polyethylene glycol (PEG) and other hydrophilic polymers restore the normal rate of surfactant adsorption to the interface, which re-establishes low surface tensions on compression. PEG does so by generating an entropic depletion attraction between the surfactant aggregates and interface, reducing the energy barrier to adsorption imposed by the albumin. For a fixed composition of 10 g/L ...

  6. 旅游景区形象对顾客忠诚的影响研究%The Effects of Tourist Attractions Image on Customer Loyalty

    Institute of Scientific and Technical Information of China (English)

    邱宏亮; 吴雪飞; 钱正英

    2012-01-01

    Combined the review of related literature with the qualitative research, the four-dimension measurement model of tourist attractions image is proposed. And the structural model of each dimension of tourist attractions image affecting relationship among value, satisfaction and loyalty is constructed. Empirical results indicate that: (1)the measurement model of tourist attractions image which includes landscape and health, tourist attractions price, tourist attractions service, infrastructure has been ac- ceptable levels of reliability, overall fit, convergent validity, discriminant validity; (Z)Each dimension of tourist attractions image has different effects on the customer's value-satisfaction-loyalty.%采用文献回顾和定性研究相结合的方法,提出了旅游景区形象4维度测量模型。基于此,建立了旅游景区形象各维度对顾客忠诚的作用机制模型.数据研究表明:(1)笔者开发的旅游景区形象量表具有较好的信度水平、整体拟合优度、收敛效度、判别效度,它包括风景与卫生、景区价格、景区服务、基础设施等4个结构维度;(2)旅游景区形象各维度对顾客忠诚存在不同的作用机理与影响效应.

  7. Susceptibility to selected insecticides and risk assessment in the insect egg parasitoid Trichogramma confusum (Hymenoptera: Trichogrammatidae).

    Science.gov (United States)

    Wang, Yanhua; Chen, Liping; An, Xuehua; Jiang, Jinhua; Wang, Qiang; Cai, Leiming; Zhao, Xueping

    2013-02-01

    The parasitoid Trichogramma confusum Viggiani (Hymenoptera: Trichogrammatidae) is an important natural enemy of many lepidopterans throughout the world. Extensive toxicological tests have clarified the toxic effects of insecticides on trichogrammatids, but only few studies have examined these effects on T. confusum. Among the seven classes of tested chemicals, organophosphates and carbamates exhibited the highest intrinsic toxicity to the parasitoid with LC50 values ranging from 0.037 (0.030-0.046) to 0.29 (0.23-0.38) and from 0.17 (0.15-0.19) to 1.61 (1.45-1.79) mg AI L(-1), respectively. They were followed by phenylpyrazoles, avermectins, pyrethroids, and neonicotinoids, which induced variable toxicity responses with LC50 values ranging from 0.63 to 45.26, 1.06-21.73, 3.89-19.36, and 0.24-754.2 mg AI L(-1), respectively. In contrast, insect growth regulators (IGRs) showed the least toxicity to the parasitoid with LC50 values ranging from 3,907 (3,432-4,531) to 10,154 (8,857-12,143) mg AI L(-1). A risk quotient analysis indicated that neonicotinoids (except thiamethoxam), avermectins, pyrethroids, IGRs, and phenylpyrazoles are safe, but organophosphates and carbamates are slightly to moderately or dangerously toxic to T. confusum. This study provides informative data for implementing both biological and chemical control strategies in integrated pest management of lepidopterans. PMID:23448026

  8. Can the Understory Affect the Hymenoptera Parasitoids in a Eucalyptus Plantation?

    Science.gov (United States)

    Dall’Oglio, Onice Teresinha; Ribeiro, Rafael Coelho; Ramalho, Francisco de Souza; Fernandes, Flávio Lemes; Wilcken, Carlos Frederico; de Assis Júnior, Sebastião Lourenço; Rueda, Rosa Angélica Plata; Serrão, José Eduardo; Zanuncio, José Cola

    2016-01-01

    The understory in forest plantations can increase richness and diversity of natural enemies due to greater plant species richness. The objective of this study was to test the hypothesis that the presence of the understory and climatic season in the region (wet or dry) can increase the richness and abundance of Hymenoptera parasitoids in Eucalyptus plantations, in the municipality of Belo Oriente, Minas Gerais State, Brazil. In each eucalyptus cultivation (five areas of cultivation) ten Malaise traps were installed, five with the understory and five without it. A total of 9,639 individuals from 30 families of the Hymenoptera parasitoids were collected, with Mymaridae, Scelionidae, Encyrtidae and Braconidae being the most collected ones with 4,934, 1,212, 619 and 612 individuals, respectively. The eucalyptus stands with and without the understory showed percentage of individuals 45.65% and 54.35% collected, respectively. The understory did not represent a positive effect on the overall abundance of the individuals Hymenoptera in the E. grandis stands, but rather exerted a positive effect on the specific families of the parasitoids of this order. PMID:26954578

  9. Impact of insecticides on parasitoids of the leafminer, Liriomyza trifolii, in pepper in south Texas.

    Science.gov (United States)

    Hernández, Ricardo; Harris, Marvin; Liu, Tong-Xian

    2011-01-01

    Liriomyza leafminers (Diptera: Agromyzidae) are cosmopolitan, polyphagous pests of horticultural plants and many are resistant to insecticides. Producers in South Texas rely on insecticides as the primary management tool for leafminers, and several compounds are available. The objective of this study is to address the efficacy of these compounds for controlling Liriomyza while minimizing their effects against natural enemies. Research plots were established at Texas AgriLife research center at Weslaco, Texas in fall 2007 and spring 2008 seasons, and peppers were used as a model crop. Plots were sprayed with novaluron, abamectin, spinetoram, lambda-cyhalothrin and water as treatments according to leafminer infestation; insecticide efficacy was monitored by collecting leaves and infested foliage. Plant phenology was also monitored. Novaluron was the most effective insecticide and lambda-cyhalothrin showed resurgence in leafminer density in fall 2007 and no reduction in spring 2008. Other compounds varied in efficacy. Novaluron showed the least number of parasitoids per leafminer larva and the lowest parasitoid diversity index among treatments followed by spinetoram. Liriomyza trifolii (Burgess) was the sole leafminer species on peppers, and 19 parasitoid species were found associated with this leafminer. Application of these insecticides for management of leafminers with conservation of natural enemies is discussed. PMID:21864155

  10. Attractants in purified diets

    OpenAIRE

    Pascual, Felicitas P.

    1980-01-01

    Juvenile Penaeus monodon were reared on purified diets containing different attractants used to gelatinize the cornstarch: plain water, shrimp, mussel, squid or trash fish extract. The highest survival rate was observed in the group given the shrimp attractant, followed by mussel, fish and squid. However growth appeared best in the diet containing mussel extract. Mussel extract apparently can be used to enhance the attractability of purified diets.

  11. Attraction of Tomicus yunnanensis (Coleoptera: Scolytidae to Yunnan Pine Logs with and without Periderm or Phloem: An Effective Monitoring Bait

    Directory of Open Access Journals (Sweden)

    Rong Chun Lu

    2012-01-01

    Full Text Available The Yunnan pine shoot beetle, Tomicus yunnanensis Kirkendall and Faccoli (Coleoptera: Scolytinae is an important pest of Yunnan pine (Pinus yunnanensis Franch in China. Experiments with host log baits were done to develop a pest monitoring system using host tree kairomone. Five Yunnan pine logs (each 10–15 cm diam. × 30-cm long in a trap-log bundle were treated by peeling periderm (outer bark off to expose the phloem, and half of each log was covered with sticky adhesive to capture any attracted adult beetles. Significantly, more beetles were attracted and caught on the periderm-peeled logs (ca 30 beetles/m2 log surface/day than on untreated control logs with adhesive (ca 2.5/m2/day. No significant differences were observed between catches on logs taken from lower or upper halves of Yunnan pines. T. yunnanensis flies mostly during the afternoon according to trap catches throughout the day. Attraction to the periderm-peeled logs decreased considerably when they were peeled further to remove the phloem, indicating phloem volatiles play a role in selection of the host by the beetle. The readily-available log baits appear useful for monitoring pine shoot beetle populations in integrated pest management programs.

  12. Advances and perspectives in the mass rearing of fruit fly parasitoids in Mexico

    International Nuclear Information System (INIS)

    Biological control by augmentation is applied in Mexico as part of an integrated pest management program against native fruit flies of the genus Anastrepha Schiner. The exotic parasitoid Diachasmimorpha longicaudata has been the most important species used within this context. A program for the mass rearing of 50 million parasitized pupa per week has been established in southeast Mexico, and these are released into the field according to a yearly national plan based on industry requirements. In order to reduce costs and optimize procedures, important advances have been made in the technology for mass production, including an increase in the weight of host larvae (24 mg), changes in the management of host exposition, improvements in the management of environmental conditions, suitability in time and motions are the main areas addressed. Furthermore, a quality control program is routinely applied, and the key parameters under constant evaluation are: 1) weight and volume of host larvae, 2) host mortality after exposure, 3) weight and volume of pupae, and 4) percent parasitoid viability and percent emergence. Good performance in these parameters produces adults with adequate longevity and fecundity, high flight ability and good searching behavior. The introduced egg parasitoid Fopius arisanus and the native pupal parasitoid Coptera hawardi are being evaluated for use in the future as a complement to releases into the field of D. longicaudata. Manipulating host size and exposition time, the use of starting diet and suppressing host development by irradiation, have permitted the effective use of Anastrepha eggs as hosts for the rearing of F. arisanus. Further achievements in the mass rearing of C. haywardi (e.g., the suppression of unparasitized hosts after irradiation), could give us the opportunity to employ new options to reinforce the augmentative biological control of Anastrepha fruit flies in Mexico. (author)

  13. Advances and perspectives in the mass rearing of fruit fly parasitoids in Mexico

    Energy Technology Data Exchange (ETDEWEB)

    Cancino, Jorge; Montoya, Pablo [Secretaria de Agricultura, Ganaderia, Desarrollo Rural, Pesca y Alimentacion (DGSV/SENASICA/SAGARPA), Chiapas (Mexico). Servicio Nacional de Sanidad, Inocuidad y Calidad Agroalimentaria. Programa Moscamed-Moscafrut

    2006-07-01

    Biological control by augmentation is applied in Mexico as part of an integrated pest management program against native fruit flies of the genus Anastrepha Schiner. The exotic parasitoid Diachasmimorpha longicaudata has been the most important species used within this context. A program for the mass rearing of 50 million parasitized pupa per week has been established in southeast Mexico, and these are released into the field according to a yearly national plan based on industry requirements. In order to reduce costs and optimize procedures, important advances have been made in the technology for mass production, including an increase in the weight of host larvae (24 mg), changes in the management of host exposition, improvements in the management of environmental conditions, suitability in time and motions are the main areas addressed. Furthermore, a quality control program is routinely applied, and the key parameters under constant evaluation are: 1) weight and volume of host larvae, 2) host mortality after exposure, 3) weight and volume of pupae, and 4) percent parasitoid viability and percent emergence. Good performance in these parameters produces adults with adequate longevity and fecundity, high flight ability and good searching behavior. The introduced egg parasitoid Fopius arisanus and the native pupal parasitoid Coptera hawardi are being evaluated for use in the future as a complement to releases into the field of D. longicaudata. Manipulating host size and exposition time, the use of starting diet and suppressing host development by irradiation, have permitted the effective use of Anastrepha eggs as hosts for the rearing of F. arisanus. Further achievements in the mass rearing of C. haywardi (e.g., the suppression of unparasitized hosts after irradiation), could give us the opportunity to employ new options to reinforce the augmentative biological control of Anastrepha fruit flies in Mexico. (author)

  14. Parasitoid complex of Zygaena filipendulae L. (Lepidoptera: Zygaenidae

    Directory of Open Access Journals (Sweden)

    Žikić V.

    2013-01-01

    Full Text Available Caterpillars of Zygaena filipendulae Linnaeus were sampled during May and June in the Sićevo Gorge in southern Serbia. All parasitized larvae were found on grey elm trees (Ulmus canescens. During the short period before metamorphosis of Z. filipendulae, we found the whole specter of parasitoid wasps: Cotesia zygaenarum Marshall (Braconidae, Gelis agilis (Fabricius and Mesochorus velox Holmgren (Ichneumonidae, Elasmus platyedrae Ferrière and Pediobius sp. (Eulophidae, Eupelmus vesicularis (Retzius (Eupelmidae and Brachymeria tibialis (Walker (Chalcididae. Beside hymenopteran parasitoids, we found parasitoid flies from the family Tachinidae, Phryxe nemea (Meigen (Diptera. All 46 observed Z. filipendulae larvae found on grey elm trees were parasitized, but three pupae were found directly on Lotus corniculatus. Two species are newly reported as parasitoids of Z. filipendulae: E. platyedrae and Eupelmus vesicularis and three species (G. agilis, M. velox and E. platyedrae are new to the fauna of Serbia. [Projekat Ministarstva nauke Republike Srbije, br. 43001

  15. Dead ant walking: a myrmecophilous beetle predator uses parasitoid host location cues to selectively prey on parasitized ants.

    Science.gov (United States)

    Mathis, Kaitlyn A; Tsutsui, Neil D

    2016-08-17

    Myrmecophiles (i.e. organisms that associate with ants) use a variety of ecological niches and employ different strategies to survive encounters with ants. Because ants are typically excellent defenders, myrmecophiles may choose moments of weakness to take advantage of their ant associates. This hypothesis was studied in the rove beetle, Myrmedonota xipe, which associates with Azteca sericeasur ants in the presence of parasitoid flies. A combination of laboratory and field experiments show that M. xipe beetles selectively locate and prey upon parasitized ants. These parasitized ants are less aggressive towards beetles than healthy ants, allowing beetles to eat the parasitized ants alive without interruption. Moreover, behavioural assays and chemical analysis reveal that M. xipe are attracted to the ant's alarm pheromone, the same secretion used by the phorid fly parasitoids in host location. This strategy allows beetles access to an abundant but otherwise inaccessible resource, as A. sericeasur ants are typically highly aggressive. These results are the first, to our knowledge, to demonstrate a predator sharing cues with a parasitoid to gain access to an otherwise unavailable prey item. Furthermore, this work highlights the importance of studying ant-myrmecophile interactions beyond just their pairwise context. PMID:27512148

  16. Using parasitoid wasps in Integrated Pest Management in museums against biscuit beetle (Stegobium paniceum and webbing clothes moth (Tineola bisselliella

    Directory of Open Access Journals (Sweden)

    Pascal Querner

    2011-08-01

    Full Text Available Biscuit beetle (Stegobium paniceum and webbing clothes moth (Tineola bisselliella cause much damage to museum objects. Some objects and materials are very attractive to these two pest species and objects are often re-infested after treatment. For some years parasitoid wasps have been used in biological pest control to treat and reduce infestations of stored product pests in food processing facilities. Their application in museums is still new and in a research stage. Results from five different museums in Germany and Austria and their application are presented. Lariophagus distinguendus wasps were released against Stegobium paniceum in the municipal library Augsburger Stadtarchiv (Germany, the Ethnological Museum in Berlin (Germany and the Picture Gallery in the Kunsthistorisches Museum in Vienna (Austria. Trichogramma evanescens were released against Tineola bisselliella in the Technisches Museum in Vienna (Austria and in the Deutsches Museum Verkehrszentrum in Munich (Germany. Results show that for active biscuit beetle infestations good results can be expected using the Lariophagus distinguendus in museums. Active clothes moth infestations are harder to treat but with a very regular and long-term exposure to the wasps, the clothes moth population can be reduced over the years. We see the application of parasitoid wasps as part of an Integrated Pest Management concept that should be used besides regular insect monitoring and other preventive measures. Difficulties, limitations and research needs in the application of parasitoid wasps in museums are discussed.

  17. Complex interactions envolving a gall midge Myrciamyia maricaensis Maia (Diptera, Cecidomyiidae, phytophagous modifiers and parasitoids

    Directory of Open Access Journals (Sweden)

    Ferraz Fernando Fortunato Faria

    2003-01-01

    Full Text Available Myrciamyia maricaensis Maia, 1995 (Diptera, Cecidomyiidae induces a gall in lateral and apical shoots in the plant Myrcia lundiana Kiaersk (Myrtaceae which is used and modified by two eulophid wasps species. In both cases the gall former species suffer high rate of attack exceeding the importance of parasitoid species as mortality factors. In this study these interactions are described and their effects as mortality of gall former. The intensity of occurrence of the two eulophid species as modifiers and of microhymenopteran parasitoids, and the relative importance of these species as mortality agents of the M. maricaensis larvae is compared. This comparison reveals that two modifiers species found in the gall tissue modification causing the death of the M. maricaensis larva and it is a more important factor of mortality than the cecidomyiid larva parasitism. The fluctuation of the number of each type of gall along the year was monitored in the research field and confirmed in numerical and in synchronic terms of occurrence of the galls; the importance of the species of the gall modifier eulophids, particularly one of these species, as factors of mortality of the M. maricaensis larvae and justified our comparing the relationship between these species and M. maricaensis as similar to the parasitoid-host relationship. The gall shape modification by one of the eulophids allows the occurrence of other inquiline insect species, what means that this gall modification becomes it more heterogeneous and allows the increase of the species richness to the system.

  18. Intelligence and Physical Attractiveness

    Science.gov (United States)

    Kanazawa, Satoshi

    2011-01-01

    This brief research note aims to estimate the magnitude of the association between general intelligence and physical attractiveness with large nationally representative samples from two nations. In the United Kingdom, attractive children are more intelligent by 12.4 IQ points (r=0.381), whereas in the United States, the correlation between…

  19. Assertiveness and Physical Attractiveness.

    Science.gov (United States)

    Kleim, David M.; And Others

    Earlier research investigating the relationship between physical attractiveness and assertiveness found that physically attractive females were more assertive than other females. To investigate this relationship further and to broaden the scope of the study, 69 students were videotaped in groups of five to ten while responding to open-ended…

  20. Packing of Fruit Fly Parasitoids for Augmentative Releases

    OpenAIRE

    Pablo Montoya; Lía Ruiz; Jorge Cancino

    2012-01-01

    The successful application of Augmentative Biological Control (ABC) to control pest fruit flies (Diptera: Tephritidae) confronts two fundamental requirements: (1) the establishment of efficient mass rearing procedures for the species to be released, and (2) the development of methodologies for the packing and release of parasitoids that permit a uniform distribution and their optimal field performance under an area-wide approach. Parasitoid distributions have been performed by ground and by a...

  1. Trichogramma parasitoids alter the metabolic physiology of Manduca eggs

    OpenAIRE

    Potter, Kristen A.; Woods, H. Arthur

    2012-01-01

    Egg parasitoids face unique developmental constraints. First, they have exceptionally limited resources to support themselves and their siblings through three life stages. Second, they develop within the physiological system of another species, which they modify to their own ends. We examined how these constraints affect the metabolic physiology of egg parasitism, and whether parasitoids retool their host eggshell to account for their different metabolic demands. Higher-conductance eggshells ...

  2. Effects of ionizing radiation on codling moth Cydia pomonella (L) female's ability to attract males in the field

    International Nuclear Information System (INIS)

    Codling moth Cydia pomonella L. males and females were exposed to three levels of gamma radiation (0, 250 and 350 Gy). Females were used in pheromone traps (instead of pheromone capsules) inside wire cages at a rate of one female / trap. Males were released in a 2 * 2 m square in the middle of the orchard and the number of caught males (wild and released ) in female baited traps was recorded. Results showed an inverse relationship between radiation dose and the ability of females to attract males (wild and released). Contrary to that, result showed that the higher the dose, the lower was the number of males caught in female baited traps. (author)

  3. Lethal and sublethal effects of essential oils from Pittosporum undulatum and Hedychium gardnerianum on the egg parasitoid Trichogramma cordubensis (Hymenoptera: Trichogrammatidae

    OpenAIRE

    Furtado, Cláudia da Silva

    2013-01-01

    ABSTRACT: Laboratory and field studies have shown that Trichogramma wasps are highly susceptible to most broadspectrum insecticides, reducing their efficacy as biological control agents. Thus, the integration of this biological control agent with other methods requires knowledge of the lethal and sublethal effects they may have on these natural enemies. To promote environmentally friendly pest control methods in Azorean crops, this research aimed at assessing the safety of essential oils of P...

  4. The parasitoid, Cotesia flavipes (Cameron) (Hymenoptera: Braconidae), influences food consumption and utilization by larval Diatraea saccharalis (F.) (Lepidoptera: Crambidae).

    Science.gov (United States)

    Rossi, Guilherme Duarte; Salvador, Gabriela; Cônsoli, Fernando Luis

    2014-10-01

    Parasitoids exploit host insects for food and other resources; they alter host development and physiology to optimize conditions to favor parasitoid development. Parasitoids influence their hosts by injecting eggs, along with a variety of substances, including venoms, polydnaviruses, ovarian fluids, and other maternal factors, into hosts. These factors induce profound changes in hosts, such as behavior, metabolism, endocrine events, and immune defense. Because endoparasitoids develop and consume tissues from within their hosts, it is reasonable to suggest that internal parasitization would also influence host food consumption and metabolism. We report on the effects of parasitism by Cotesia flavipes on the food consumption and utilization of its host, Diatraea saccharalis. Cotesia flavipes reduces the host food consumption, but parasitized larvae considered a unit with their parasitoid's attained the same final weight as the nonparasitized larvae. Nutritional indices, midgut activities of carbohydrases, and trypsin of parasitized and nonparasitized D. saccharalis were assessed. Parasitized larvae had reduced relative food consumption, metabolic and growth rates, coupled with higher efficiency for conversion of the digested, but not ingested, food into body mass. Parasitism also affected food flux through the gut and protein contents in the midgut of parasitized larvae. The activity of α-amylase and trehalase in parasitized host was enhanced in the first day after parasitism relative to control larvae. Saccharase activity remained unchanged during larval development. Trypsin activity was reduced from the fifth to ninth day after parasitism. We argue on the mechanisms involved in host food processing after parasitism. PMID:25042594

  5. Conservation of Diadegma semiclausum Hellen. Parasitoids as Biological Control to Plutella xylostella Linn. with Adult Food Exploration

    Directory of Open Access Journals (Sweden)

    Fri Maulina

    2013-01-01

    Full Text Available Diadegma semiclausum Hellen. parasitoid (Hymenoptera : Ichneumonidae is a potential natural enemy to Plutella xylostella Linn. larvae (Lepidoptera : Yponomeutidae that attacks Brassicaceae crops (crucifers such as cabbage  (Brassica oleraceae var. capitata  and cauliflower (Brassica oleraceae var. italica.  The failures of biological control programs caused by the lack of suitable charbohydrate food sources to adult parasitoid, and its effects the adult reproduction, so its important to use food sources which is suitable to D. semiclausum longevity and fecundity for good existence in field. The aim of research is to identification kind of Brassicaceae wild flowers  and to get a better Brassicaceae wild flowers  as  food to  D. semiclausum adult parasitoids.   This research has been conducted during the periods of Mei to November 2008 in laboratory and screen house of Payakumbuh Agriculture Polytechnic.  This research consist of descriptive method to identification and a series with Completely Randomized Design.  The last  research is testing Brassicaceae wild flowers (Rorippa indica (Nasturtium indicum,  Cardamine hirsuta, Bunias orientalis,  R. indica (N.  heterophylum as food of D. semiclausum adult parasitoids with four replications.    Analysis of variance is performed on the data with SAS Systems.  The result of research showed that brassicaceae wild flowers were testing a potential food sources  for D. semiclausum adult but no one the best from its.

  6. The effect of public Polices on the attractiveness of emerging countries for the development of innovation activities by multinational firms

    Directory of Open Access Journals (Sweden)

    Eva Stal

    2009-03-01

    Full Text Available Multinational firms contribute to the development of innovative capacity in countries where they establish subsidiaries and research centers. However, they still conduct most of their R&D at home or in developed countries’ based subsidiaries. The resources offered by the host country affect the level of local R&D, and they constitute what Dunning calls the L (location variable of his Eclectic Paradigm of International Production. It includes a big domestic market, availability of qualified and low-cost professionals, technological (universities and research institutes and communication infrastructure, protection of intellectual property rights, commercial policies and the scale of the national technological effort. These aspects define the type and scope of R&D that will be done locally. The article aims at showing that emerging countries need a strong action from the government, in order to improve their attractiveness to MNCs. The Brazilian Informatics Act is an example of a successful policy, which attracted many foreign companies, in exchange of tax incentives and the requirement of local R&D activities. The results are based on interviews with a group of firms established in the Campinas region.

  7. Effects of Peganum harmala (Zygophyllaceae) seed extract on the olive fruit fly (Diptera: Tephritidae) and its larval parasitoid Psyttalia concolor (Hymenoptera: Braconidae).

    Science.gov (United States)

    Rehman, Junaid Ur; Wang, Xin-Geng; Johnson, Marshall W; Daane, Kent M; Jilani, Ghulam; Khan, Mir A; Zalom, Frank G

    2009-12-01

    Peganum harmala L. (Zygophyllaceae) is an herb native to arid and semiarid regions of Central Asian deserts. This study investigated the effects of ethanol extracts of P. harmala seeds on the olive fruit fly, Bactrocera oleae (Rossi) (Diptera: Tephritidae), i.e., adult repellency, reproductive activity, and larval growth, as well as parasitism levels by Psyttalia concolor (Szépligeti). Olive fruit treated with 2% extract reduced B. oleae oviposition. In choice tests, female B. oleae spent >99% of their time foraging on untreated fruit rather than P. harmala-treated fruit. These changes in ovipositional behavior resulted in a nearly 30-fold decrease in oviposition marks on treated fruit compared with untreated fruit during a 48 h exposure period. When female B. oleae were fed liquid diet containing 0.2% P. harmala extract, there was no effect on the number of ovipositional marks on exposed fruit, but up to 21.4% of the deposited eggs were deformed. SDS-polyacrylamide gel electrophoresis analyses of deformed eggs revealed that some protein bands were missing. Consequently, the number of offspring produced by treated females was lower than by untreated females. Neither the sex ratio nor body size of the fly's offspring were affected by adults fed diet containing 0.2% P. harmala extract. However, there was a slightly prolonged developmental time from egg to adult. Parasitism of larval B. oleae by P. concolor was not affected by infested fruit treatment with 2% P. harmala extract. P. harmala extracts as a potential control for insect pest species are discussed. PMID:20069853

  8. Functional and evolutionary insights from the genomes of three parasitoid Nasonia species

    NARCIS (Netherlands)

    Werren, John H.; Richards, Stephen; Desjardins, Christopher A.; Niehuis, Oliver; Gadau, Juergen; Colbourne, John K.; Beukeboom, Leo W.; Desplan, Claude; Elsik, Christine G.; Grimmelikhuijzen, Cornelis J. P.; Kitts, Paul; Lynch, Jeremy A.; Murphy, Terence; Oliveira, Deodoro C. S. G.; Smith, Christopher D.; van de Zande, Louis; Worley, Kim C.; Zdobnov, Evgeny M.; Aerts, Maarten; Albert, Stefan; Anaya, Victor H.; Anzola, Juan M.; Barchuk, Angel R.; Behura, Susanta K.; Bera, Agata N.; Berenbaum, May R.; Bertossa, Rinaldo C.; Bitondi, Marcia M. G.; Bordenstein, Seth R.; Bork, Peer; Bornberg-Bauer, Erich; Brunain, Marleen; Cazzamali, Giuseppe; Chaboub, Lesley; Chacko, Joseph; Chavez, Dean; Childers, Christopher P.; Choi, Jeong-Hyeon; Clark, Michael E.; Claudianos, Charles; Clinton, Rochelle A.; Cree, Andrew G.; Cristino, Alexandre S.; Dang, Phat M.; Darby, Alistair C.; de Graaf, Dirk C.; Devreese, Bart; Dinh, Huyen H.; Edwards, Rachel; Elango, Navin; Elhaik, Eran; Ermolaeva, Olga; Evans, Jay D.; Foret, Sylvain; Fowler, Gerald R.; Gerlach, Daniel; Gibson, Joshua D.; Gilbert, Donald G.; Graur, Dan; Grunder, Stefan; Hagen, Darren E.; Han, Yi; Hauser, Frank; Hultmark, Dan; Hunter, Henry C.; Jhangian, Shalini N.; Jiang, Huaiyang; Johnson, Reed M.; Jones, Andrew K.; Junier, Thomas; Kadowaki, Tatsuhiko; Kamping, Albert; Kapustin, Yuri; Kechavarzi, Bobak; Kim, Jaebum; Kim, Jay; Kiryutin, Boris; Koevoets, Tosca; Kovar, Christie L.; Kriventseva, Evgenia V.; Kucharski, Robert; Lee, Heewook; Lee, Sandra L.; Lees, Kristin; Lewis, Lora R.; Loehlin, David W.; Logsdon, John M.; Lopez, Jacqueline A.; Lozado, Ryan J.; Maglott, Donna; Maleszka, Ryszard; Mayampurath, Anoop; Mazur, Danielle J.; McClure, Marcella A.; Moore, Andrew D.; Morgan, Margaret B.; Muller, Jean; Munoz-Torres, Monica C.; Muzny, Donna M.; Nazareth, Lynne V.; Neupert, Susanne; Nguyen, Ngoc B.; Nunes, Francis M. F.; Oakeshott, John G.; Okwuonu, Geoffrey O.; Pannebakker, Bart A.; Pejaver, Vikas R.; Peng, Zuogang; Pratt, Stephen C.; Predel, Reinhard; Pu, Ling-Ling; Ranson, Hilary; Raychoudhury, Rhitoban; Rechtsteiner, Andreas; Reese, Justin T.; Reid, Jeffrey G.; Riddle, Megan; Robertson, Il High M.; Romero-Severson, Jeanne; Rosenberg, Miriam; Sackton, Timothy B.; Sattelle, David B.; Schluens, Helge; Schmitt, Thomas; Schneider, Martina; Schueler, Andreas; Schurko, Andrew M.; Shuker, David M.; Simoes, Zila L. P.; Sinha, Saurabh; Smith, Zachary; Solovyev, Victor; Souvorov, Alexandre; Springauf, Andreas; Stafflinger, Elisabeth; Stage, Deborah E.; Stanke, Mario; Tanaka, Yoshiaki; Telschow, Arndt; Trent, Carol; Vattathil, Selina; Verhulst, Eveline C.; Viljakainen, Lumi; Wanner, Kevin W.; Waterhouse, Robert M.; Whitfield, James B.; Wilkes, Timothy E.; Williamson, Michael; Willis, Judith H.; Wolschin, Florian; Wyder, Stefan; Yamada, Takuji; Yi, Soojin V.; Zecher, Courtney N.; Zhang, Lan; Gibbs, Richard A.

    2010-01-01

    We report here genome sequences and comparative analyses of three closely related parasitoid wasps: Nasonia vitripennis, N. giraulti, and N. longicornis. Parasitoids are important regulators of arthropod populations, including major agricultural pests and disease vectors, and Nasonia is an emerging

  9. Functional and evolutionary insights from the genomes of three parasitoid Nasonia species

    DEFF Research Database (Denmark)

    Werren, John H; Richards, Stephen; Desjardins, Christopher A;

    2010-01-01

    We report here genome sequences and comparative analyses of three closely related parasitoid wasps: Nasonia vitripennis, N. giraulti, and N. longicornis. Parasitoids are important regulators of arthropod populations, including major agricultural pests and disease vectors, and Nasonia is an emergi...

  10. Effects of ionizing radiation on codling moth cydia pomonella (L) female's ability to attract males in the field

    International Nuclear Information System (INIS)

    Codling moth Cydia pomonella L. males and females were exposed to three levels of gamma radiation (0, 250 and 350 Gy). Females were used in pheromone traps (instead of pheromone capsules) inside wire cages at a rate of one female / trap. Males were released in a 2 x 2 m square in the middle of the orchard and the number of caught males (wild and released ) in female baited traps was recorded. Results showed an inverse relationship between radiation dose and the ability of females to attract males (wild and released). Contrary to that, result showed that the higher the dose, the lower was the number of males caught in female baited traps. (author)

  11. Effectiveness of attract-and-kill systems using methyl eugenol incorporated with neonicotinoid insecticides against the oriental fruit fly (Diptera: Tephritidae).

    Science.gov (United States)

    Chuang, Yi-Yuan; Hou, Roger F

    2008-04-01

    Laboratory bioassays and field trials were conducted to evaluate an "attract-and-kill" system using methyl eugenol (ME) with neonicotinoid insecticides against male oriental fruit fly, Bactrocera dorsalis (Hendel) (Diptera: Tephritidae). In laboratory bioassays, mortality of male flies resulting from the conventional toxicant, naled was 98.3-100% at 24 through 72 h after treatment, whereas the neonicotinoid insecticides imidacloprid and acetamiprid caused only approximately 60-80% at 24 through 72 h after treatment. In the assays of residual effect, naled was persistent up to 96 wk, whereas imidacloprid or acetamiprid was persistent up to 150 wk, resulting in 38.9 or 61.2% male mortality, respectively. Imidacloprid, in particular, caused a delayed lethal effect on flies. In another experiment, male mortality within 28 wk from clothianidin, another neonicotinoid insecticide, was approximately 80% after exposure for 24 h, suggesting a delayed lethal effect similar to those treated with imidacloprid, and mortality was up to 91.8%, if observed, 72 h after treatment. In field trials, attractiveness was similar between ME alone and ME incorporated with naled or neonicotinoids, indicating that addition of these insecticides to ME in traps is not repellent to B. dorsalis males. Using an improved wick-typed trap with longer attractiveness for simulating field application, addition of imidacloprid or acetamiprid maintained 40.1 or 64.3% male mortality, respectively, when assayed once every 2 wk from traps placed in orchards for 42 wk without changing the poison, whereas incorporation with naled resulted in as high as 98.1% after 34 wk and approximately 80% at 42 wk, indicating that persistence is increased compared with sugarcane fiberboard blocks for carrying poison attractants. This study also suggests that neonicotinoid insecticides could be used as an alternative for broad-spectrum insecticides as toxicants in fly traps. PMID:18459398

  12. Effects of different animal manures on attraction and reproductive behaviors of common house fly, Musca domestica L.

    Science.gov (United States)

    Shah, Rizwan Mustafa; Azhar, Faheem; Shad, Sarfraz Ali; Walker, William B; Azeem, Muhammad; Binyameen, Muhammad

    2016-09-01

    Insects rely mainly on their well-developed and highly sophisticated olfactory system to discriminate volatile cues released from host and nonhost substances, mates, oviposition substrates, and food sources. Onset of first mating, mating duration, and onset of first oviposition, oviposition period, fecundity (number of eggs laid by a female), and longevity of freshly emerged Musca domestica L. (Diptera: Muscidae) adults were observed in the presence of different animal manures: cow, horse, donkey, poultry, and an artificial diet. The M. domestica adults exposed to horse manure showed a delay in onset of first mating and first oviposition, prolonged mating duration, and reduced fecundity compared to the artificial diet (control). Likewise, the fecundity was reduced in the presence of donkey manure as compared to artificial diet. The onset of first mating was delayed and duration of first mating was shortened in the presence of cow manure as compared to artificial diet and no oviposition was observed throughout the duration of the experiment. However, the reproductive behaviors and all fitness measures in adults exposed to poultry manure were similar or even better, compared to the artificial diet. Surprisingly, in a free-choice attraction assay, the highest numbers of adult flies were attracted toward the cow manure as compared to all other manures as well as the artificial diet. However, the numbers of flies captured in all other types of manures were not different than the artificial diet (control). Furthermore, chemical analysis of headspace samples of manures revealed qualitative differences in odor (volatile) profiles of all manures and artificial diet, indicating that behavioral differences could be due to the differences in the volatile chemistry of the adult ovipositional substrates and larval growth mediums. This study may contribute toward both understanding the linkage between ecological adaptations and host selection mechanisms and the development of

  13. Vocal attractiveness increases by averaging.

    Science.gov (United States)

    Bruckert, Laetitia; Bestelmeyer, Patricia; Latinus, Marianne; Rouger, Julien; Charest, Ian; Rousselet, Guillaume A; Kawahara, Hideki; Belin, Pascal

    2010-01-26

    Vocal attractiveness has a profound influence on listeners-a bias known as the "what sounds beautiful is good" vocal attractiveness stereotype [1]-with tangible impact on a voice owner's success at mating, job applications, and/or elections. The prevailing view holds that attractive voices are those that signal desirable attributes in a potential mate [2-4]-e.g., lower pitch in male voices. However, this account does not explain our preferences in more general social contexts in which voices of both genders are evaluated. Here we show that averaging voices via auditory morphing [5] results in more attractive voices, irrespective of the speaker's or listener's gender. Moreover, we show that this phenomenon is largely explained by two independent by-products of averaging: a smoother voice texture (reduced aperiodicities) and a greater similarity in pitch and timbre with the average of all voices (reduced "distance to mean"). These results provide the first evidence for a phenomenon of vocal attractiveness increases by averaging, analogous to a well-established effect of facial averaging [6, 7]. They highlight prototype-based coding [8] as a central feature of voice perception, emphasizing the similarity in the mechanisms of face and voice perception. PMID:20129047

  14. Physical Attractiveness and Courtship

    Science.gov (United States)

    Silverman, Irwin

    1971-01-01

    This study shows a high and disquieting degree of similarity in physical attractiveness between dating partners, and suggests also that more similar partners tend to form stronger romantic attachments. (Author)

  15. Host preference of the egg parasitoids Telenomus remus and Trichogramma pretiosum in laboratory

    OpenAIRE

    Maria Mirmes Paiva Goulart; Adeney de Freitas Bueno; Regiane Cristina Oliveira de Freitas Bueno; Adenil Ferreira Diniz

    2011-01-01

    Host preference of the egg parasitoids Telenomus remus and Trichogramma pretiosum in laboratory. This research aimed to evaluate the host preference of the egg parasitoids Telenomus remus and Trichogramma pretiosum. Trials were carried out in laboratory, under controlled environmental conditions (25 ± 2ºC temperature; 70 ± 10% RH; and 14 h photophase). The parasitoid searching behavior was evaluated based on the distribution (%) of eggs parasitized by each parasitoid, on egg masses of each ho...

  16. Physical attractiveness, employment and earnings

    OpenAIRE

    Pfeifer, Christian

    2011-01-01

    Survey data is used to estimate the impact of physical attractiveness rated by the interviewer as well as by the respondent on employment probability and labor income of men and women. In addition to mean linear and non-linear effects on earnings, simultaneous quantile regressions are applied to analyze heterogeneity across the wage distribution.

  17. [The attractiveness of various heat insulation substrates and their effect on the reproductive rate of the German cockroach and recommendations for preventing cockroaches].

    Science.gov (United States)

    Klunker, R

    1989-09-01

    Attractivity of some heat-isolating materials (glass wool, mineral wool, foam polystyrol, "texdur"-sheets and textile isolating mats) to the German cockroach, Blattella germanica L. and the effects on rate of increase were studied in the laboratory in comparison with folded cardboard as a check. The influence of structure (pressed sheets or loosely quilted materials) and exposition (single, piled or between sheets of plaster) was represented. Loose glass wool, open or between plaster sheets, shows a clearly higher attractivity than the other materials tested. increase of populations on glass wool is almost the same as on folded cardboards. The solid variants were less suitable for the settlement of the cockroaches. General recommendations for the prevention of infestations by cockroaches are given. PMID:2588704

  18. Effect of CO2 and 1-octen-3-ol attractants for estimating species richness and the abundance of diurnal mosquitoes in the southeastern Atlantic forest, Brazil

    Directory of Open Access Journals (Sweden)

    Gabriel Z Laporta

    2011-05-01

    Full Text Available Studies have shown that both carbon dioxide (CO2 and octenol (1-octen-3-ol are effective attractants for mosquitoes. The objective of the present study was to evaluate the attractiveness of 1-octen-3-ol and CO2 for diurnal mosquitoes in the southeastern Atlantic forest. A Latin square experimental design was employed with four treatments: CDC-light trap (CDC-LT, CDC-LT and 1-octen-3-ol, CDC-LT and CO2 and CDC-LT with 1-octen-3-ol and CO2. Results demonstrated that both CDC-CO2 and CDC-CO2-1-octen-3-ol captured a greater number of mosquito species and specimens compared to CDC-1-octen-3-ol; CDC-LT was used as the control. Interestingly, Anopheles (Kerteszia sp. was generally attracted to 1-octen-3-ol, whereas Aedes serratus was the most abundant species in all Latin square collections. This species was recently shown to be competent to transmit the yellow fever virus and may therefore play a role as a disease vector in rural areas of Brazil.

  19. EFFECTS OF "SWIM WITH THE TURTLES" TOURIST ATTRACTIONS ON GREEN SEA TURTLE (CHELONIA MYDAS) HEALTH IN BARBADOS, WEST INDIES.

    Science.gov (United States)

    Stewart, Kimberly; Norton, Terry; Mohammed, Hamish; Browne, Darren; Clements, Kathleen; Thomas, Kirsten; Yaw, Taylor; Horrocks, Julia

    2016-04-01

    Along the West Coast of Barbados a unique relationship has developed between endangered green sea turtles (Chelonia mydas) and humans. Fishermen began inadvertently provisioning these foraging turtles with fish offal discarded from their boats. Although initially an indirect supplementation, this activity became a popular attraction for visitors. Subsequently, demand for this activity increased, and direct supplementation or provisioning with food began. Food items offered included raw whole fish (typically a mixture of false herring [Harengula clupeola] and pilchard [Harengula humeralis]), filleted fish, and lesser amounts of processed food such as hot dogs, chicken, bread, or various other leftovers. Alterations in behavior and growth rates as a result of the provisioning have been documented in this population. The purpose of this study was to determine how tourism-based human interactions are affecting the overall health of this foraging population and to determine what potential health risks these interactions may create for sea turtles. Juvenile green sea turtles (n=29) were captured from four sites off the coast of Barbados, West Indies, and categorized into a group that received supplemental feeding as part of a tour (n=11) or an unsupplemented group (n=18) that consisted of individuals that were captured at sites that did not provide supplemental feeding. Following capture, a general health assessment of each animal was conducted. This included weight and morphometric measurements, a systematic physical examination, determination of body condition score and body condition index, epibiota assessment and quantification, and clinical pathology including hematologic and biochemical testing and nutritional assessments. The supplemented group was found to have changes to body condition, vitamin, mineral, hematologic, and biochemical values. Based on these results, recommendations were made to decrease negative behaviors and health impacts for turtles as a result

  20. Location of Host and Host Habitat by Fruit Fly Parasitoids

    Directory of Open Access Journals (Sweden)

    Pascal Rousse

    2012-11-01

    Full Text Available Augmentative releases of parasitoids may be a useful tool for the area-wide management of tephritid pests. The latter are parasitized by many wasp species, though only a few of them are relevant for augmentative biocontrol purposes. To date, nearly all the actual or potential biocontrol agents for such programs are egg or larval Opiinae parasitoids (Hymenoptera: Braconidae. Here, we review the literature published on their habitat and host location behavior, as well as the factors that modulate this behavior, which is assumed to be sequential; parasitoids forage first for the host habitat and then for the host itself. Parasitoids rely on chemical, visual, and mechanical stimuli, often strongly related to their ecology. Behavioral modulation factors include biotic and abiotic factors including learning, climatic conditions and physiological state of the insect. Finally, conclusions and perspectives for future research are briefly highlighted. A detailed knowledge of this behavior may be very useful for selecting the release sites for both inundative/augmentative releases of mass-reared parasitoids and inoculative releases for classical biocontrol.

  1. Attracting Girls to Physics

    Science.gov (United States)

    Sandow, Barbara; Marks, Ann; Borg, Anne

    2009-04-01

    In most countries the number of girls studying physics, as well female physicists in academic positions, is still low. Active recruitment at all levels is essential to change this situation. In some countries a large proportion of students are female, but career progression is difficult. Highlighting the broad spectrum of career opportunities for those with physics qualifications is a major approach in attracting girls to physics. This paper presents findings, examples of best practices, and recommendations resulting from the workshop, Attracting Girls to Physics, organized as part of the Third IUPAP International Conference on Women in Physics, Seoul, 2008.

  2. Timetable Attractiveness Parameters

    DEFF Research Database (Denmark)

    Schittenhelm, Bernd

    2008-01-01

    Timetable attractiveness is influenced by a set of key parameters that are described in this article. Regarding the superior structure of the timetable, the trend in Europe goes towards periodic regular interval timetables. Regular departures and focus on optimal transfer possibilities make these...... timetables attractive. The travel time in the timetable depends on the characteristics of the infrastructure and rolling stock, the heterogeneity of the planned train traffic and the necessary number of transfers on the passenger’s journey. Planned interdependencies between trains, such as transfers and...

  3. Host generated cues alter the foraging behavior of Cabbage butterfly, Pieris brassicae and its larval parasitoids, Cotesia glomerata and Hyposoter ebeninus

    Directory of Open Access Journals (Sweden)

    M. Debarma

    2013-09-01

    Full Text Available Effect of host-generated cues on foraging speed of herbivore as well as its natural enemies was studied under net house conditions in Meghalaya, India. Foraging speed of P. brassicae was significantly higher towards the healthy plants, whereas it was lowest towards the damaged plants along with herbivore cues. In contrast foraging speed of parasitoids H. ebeninus and C. glomerata was highest towards damaged plants along with herbivore cues and lowest towards healthy plants. It indicates that herbivore and its parasitoids respond to the volatiles generated by their host. In addition to host plants natural enemies also utilize herbivore-generated cues for their detection.

  4. Biotic and abiotic factors affecting the flight activity of Fopius arisanus, an egg-pupal parasitoid of fruit fly pests.

    Science.gov (United States)

    Rousse, P; Gourdon, F; Roubaud, M; Chiroleu, F; Quilici, S

    2009-06-01

    Climatic conditions and the physiological state of a parasitoid may alter its host selection behavior and thus its efficiency as a biological control agent. We studied the influence of these parameters on the behavior of Fopius arisanus (Sonan), an egg-pupal parasitoid of many Tephritidae. In the first experiment, we assessed in field cage assays the influence of temperature, humidity, light intensity, barometric pressure, and wind speed. Both flight and parasitism were mainly affected by temperature and humidity. However, because these two factors were strongly correlated in our experiments, the direct influence of each one cannot be specified. Flight activity was affected by variations in barometric pressure. In a second set of experiments, we conducted release and recapture assays with dyed insects to determine the influence of sex, mating status, egg load, age, and starvation on attraction toward infested fruit. Males were not attracted, suggesting that fruit are not a mating site. The egg load seemed to be a major parameter of foraging motivation. Finally, we showed that flight activity strongly decreased after 48 h of starvation. We observed a possible switch to food in the foraging motivation of starved females, but this result was impaired by poor recoveries: <10% of released females were recaptured after 96 h of starvation. We finally discuss the importance of these observations on the efficiency of F. arisanus as a biological control agent in tropical humid areas. PMID:19508801

  5. Transgenic GNA expressing potato plants augment the beneficial biocontrol of Lacanobia oleracea (Lepidoptera; Noctuidae) by the parasitoid Eulophus pennicornis (Hymenoptera; Eulophidae).

    Science.gov (United States)

    Bell, H A; Fitches, E C; Marris, G C; Bell, J; Edwards, J P; Gatehouse, J A; Gatehouse, A M

    2001-01-01

    The effect of expressing the gene encoding snowdrop lectin (Galanthus nivalis agglutinin, GNA) in transgenic potato plants, on parasitism of the phytophagous insect pest Lacanobia oleracea by the gregarious ectoparasitoid Eulophus pennicornis, was investigated in glasshouse trials. Expression of GNA (approx. 1.0% total soluble protein) by transgenic plants significantly reduced the level of pest damage, thus confirming previous studies. Furthermore, the presence of the parasitoid significantly reduced the levels of damage incurred either by the transgenic or control plants when compared to those plants grown in the absence of the parasitoid. For the GNA expressing plants the presence of the parasitoid resulted in further reductions (ca. 21%) in the level of damage caused by the pest species. The ability of the wasp to parasitise and subsequently develop on the pest larvae was not altered by the presence of GNA in the diet of the host. E. pennicornis progeny that developed on L. oleracea reared on GNA expressing plants showed no significant alteration in fecundity when compared with wasps that had developed on hosts fed on control potato plants, although mean size and longevity of female parasitoids was significantly reduced. The number of F2 progeny produced by parasitoids derived from hosts fed on GNA expressing plants was not significantly different to those produced by parasitoids from hosts fed control plants. Results from the present study demonstrate that the use of transgenic plants expressing insecticidal proteins can be compatible with the deployment of beneficial insects and that the two factors may interact in a positive manner. PMID:11252381

  6. [Interaction of Metarhizium anisopliae (Metsch.) Sorok., Beauveria bassiana (Bals.) Vuill. and the parasitoid Oomyzus sokolowskii (Kurdjumov) (Hymenoptera: Eulophidae) with larvae of diamondback moth, Plutella xylostella (L.) (Lepidoptera: Plutellidae)].

    Science.gov (United States)

    dos Santos, Hugo J G; Marques, Edmilson J; Barros, Reginaldo; Gondim, Manoel G C

    2006-01-01

    Chemical insecticides are broadly applied to control diamondback moth, Plutella xylostella (L.). Diamondback moth is a major pest of cruciferous worldwide, and resistance of this pest to insecticide has been often reported. Thus, this research investigated the interactions among the fungi Metarhizium anisopliae (Metsch.) Sorok., Beauveria bassiana (Bals.) Vuill., and the larval-pupal parasitoid Oomyzus sokolowskii (Kurdjumov) before and after application of the fungi on DBM larvae offered to the parasitoid. The experiment was carried out at 26+/-l degreeC, 75+/- 5% RH and 12h photophase using a completely randomized design, with eight treatments with six replications each. The isolates E9 of M. anisopliae and ESALQ 447 of B. bassiana, were used at the concentration of 10(7) conidia ml(-1). The results showed that M. anisopliae and B. bassiana reduced the parasitism of P. xylostella by O. sokolowskii. Additive effects were found on the mortality of P. xylostella with the different combinations among the fungi and parasitoid, except for the treatment B. bassiana inoculated 24h before exposition of the larvae to O. sokolowskii. The isolates were more efficacious when applied after exposition of the larvae to the parasitoid. The efficiency of O. sokolowskii was negatively influenced by the presence of the fungi, mainly when the fungi were applied 24h before diamondback's larvae were exposed to the parasitoid. The association of the fungi with the parasitoid presents potential to be tested in field. The use of these natural enemies in the integrated management of P. xylostella may economically improve the cabbage productive system, especially for organic farming. PMID:17348136

  7. Stress-reducing effects of indoor plants in the built healthcare environment: The mediating role of perceived attractiveness

    NARCIS (Netherlands)

    Dijkstra, K.; Pieterse, M.E.; Pruyn, A.

    2008-01-01

    Objective: Natural elements in the built healthcare environment have shown to hold potential stress-reducing properties. In order to shed light on the underlying mechanism of stress-reducing effects of nature, the present study investigates whether the stress-reducing effects of indoor plants occur

  8. Host-parasitoid evolution in a metacommunity.

    Science.gov (United States)

    Start, Denon; Gilbert, Benjamin

    2016-05-25

    Patch size and isolation are predicted to alter both species diversity and evolution; yet, there are few empirical examples of eco-evolutionary feedback in metacommunities. We tested three hypotheses about eco-evolutionary feedback in a gall-forming fly, Eurosta solidaginis and two of its natural enemies that select for opposite traits: (i) specialization and poor dispersal ability constrain a subset of natural enemies from occupying small and isolated patches, (ii) this constraint alters selection on the gall fly, causing phenotypic shifts towards traits resistant to generalist and dispersive enemies in small and isolated patches, and (iii) reduced dispersal evolves in small, isolated populations. We sampled patches in a natural metacommunity and found support for all hypotheses; Eurosta's specialist wasp parasitoid attacked fewer galls in small and isolated patches, generating a selection gradient that favoured small galls resistant to predation by a dispersive and generalist bird predator. Phenotype distributions matched this selection gradient, and these phenotypic differences were maintained in a common garden experiment. Finally, we found lower dispersal abilities in small and isolated patches, a phenotypic shift that aids in the maintenance of local adaptation. We suggest that the trophic rank and the species traits of consumers are central to evolution in metacommunities. PMID:27194705

  9. Attractiveness and activity in Internet communities

    CERN Document Server

    Ghoshal, G; Ghoshal, Gourab; Holme, Petter

    2005-01-01

    Datasets of online communication often take the form of contact sequences -- ordered lists contacts (where a contact is defined as a triple of a sender, a recipient and a time). We propose measures of attractiveness and activity for such data sets and analyze these quantities for anonymized contact sequences from an Internet dating community. For this data set the attractiveness and activity measures show broad power-law like distributions. Our attractiveness and activity measures are more strongly correlated in the real-world data than in our reference model. Effects that indirectly can make active users more attractive are discussed.

  10. Body sizes of hosts and parasitoids in individual feeding relationships

    OpenAIRE

    Joel E. Cohen; Jonsson, Tomas; Müller, Christine B.; Godfray, H. C. J.; Savage, M

    2005-01-01

    In a natural community of 49 species (12 species of aphids and 37 species of their parasitoids), body lengths of 2,151 parasitoid individuals were, to an excellent approximation, related to the body lengths of their individual aphid hosts by a power law with an exponent close to 3/4. Two alternative models predict this exponent. One is based on surface area to volume relationships. The other is based on recent developments in metabolic ecology. Both models require a changing ratio (in both ho...

  11. Investigating the effect of Casimir and van der Waals attractions on the electrostatic pull-in instability of nano-actuators

    Energy Technology Data Exchange (ETDEWEB)

    Soroush, R [Electronics Engineering Department, Islamic Azad University, Lahijan Branch, Lahijan (Iran, Islamic Republic of); Koochi, A; Haddadpour, H [Department of Aerospace Engineering, and Center of Excellence in Aerospace Systems, Sharif University of Technology, Azadi Avenue, PO Box 11165-8639, Tehran (Iran, Islamic Republic of); Kazemi, A S [School of Physics and Center for Solid State Research, Damghan University for Basic Sciences, PO Box 367164-167, Damghan (Iran, Islamic Republic of); Noghrehabadi, A [Department of Mechanical Engineering, Shahid Chamran University, PO Box 613574-333, Ahvaz (Iran, Islamic Republic of); Abadyan, M, E-mail: A.R.Noghrehabadi@scu.ac.i, E-mail: Abadyan@yahoo.co [Mechanical Engineering Group, Islamic Azad University Ramsar Branch, Ramsar Center, Ramsar (Iran, Islamic Republic of)

    2010-10-15

    This paper investigates the effect of dispersion (van der Waals and Casimir) forces on the pull-in instability of cantilever nano-actuators by considering their range of application. Adomian decomposition is introduced to obtain an analytical solution of the distributed parameter model. Dispersion forces decrease the pull-in deflection and voltage of a nano-actuator. However, the fringing field increases the pull-in deflection while decreasing the pull-in voltage of the actuator. The minimum initial gap and the detachment length of the actuator that does not stick to the substrate due to van der Waals and Casimir attractions were determined. Furthermore, the proposed approach is capable of determining the stress distribution of the actuator at the onset of instability. It is seen that Casimir and van der Waals attractions effectively reduce the maximum value of stress resultants at the onset of instability. The results indicate that Adomian decomposition is a reliable method for simulating nano-structures at submicrometer ranges.

  12. Indirect competition facilitates widespread displacement of one naturalized parasitoid of imported fire ants by another.

    Science.gov (United States)

    LeBrun, E G; Plowes, R M; Gilbert, L E

    2009-05-01

    Species abundances in natural systems are usually close to some equilibrium, making mechanisms that maintain or prevent species coexistence difficult to discern. Biological control projects provide an opportunity to observe systems transition between equilibriums as a result of the influence of the newly introduced species. In the southeastern United States and Texas, species of phorid fly parasitoids are being sequentially introduced as control agents for imported fire ants. The first two species introduced, Pseudacteon tricuspis and P. curvatus, partition the host niche based upon body size and co-exist broadly in their native range in Argentina, indicating they would form a co-existing and complementary suite of parasitoids in North America. This study examines the interaction between these parasitoids at multiple temporal and spatial scales. Surprisingly, data at all scales reveal that as P. curvatus establishes at a site it competitively displaces P. tricuspis. However, the speed of this reduction appears to differ between ecoregions, suggesting that the rate of displacement depends on environment. At the site where P. curvatus has been established the longest, this population interaction approaches complete displacement. Tests of potential mechanisms causing this displacement reveal that direct competition for host workers alters the operational sex ratio of the P. tricuspis population, but the strength of this effect is insufficient to explain the displacement. Experiments reveal the operation of a strong, indirect effect whereby locally common species preempt reproductive opportunities from rarer species by inducing host behavioral defenses. Finally, a re-examination of published data from their native range reveals that a previously overlooked negative relationship between the densities of these two species also exists there, suggesting that the same processes as those reported here also operate in South America. PMID:19537540

  13. Attractiveness of Invariant Manifolds

    CERN Document Server

    Pei, Lijun

    2011-01-01

    In this paper an operable, universal and simple theory on the attractiveness of the invariant manifolds is first obtained. It is motivated by the Lyapunov direct method. It means that for any point $\\overrightarrow{x}$ in the invariant manifold $M$, $n(\\overrightarrow{x})$ is the normal passing by $\\overrightarrow{x}$, and $\\forall \\overrightarrow{x^{'}} \\in n(\\overrightarrow{x})$, if the tangent $f(\\overrightarrow{x^{'}})$ of the orbits of the dynamical system intersects at obtuse (sharp) angle with the normal $n(\\overrightarrow{x})$, or the inner product of the normal vector $\\overrightarrow{n}(\\overrightarrow{x})$ and tangent vector $\\overrightarrow{f}(\\overrightarrow{x^{'}})$ is negative (positive), i.e., $\\overrightarrow{f}(\\overrightarrow{x^{'}}). \\overrightarrow{n}(\\overrightarrow{x}) )0$, then the invariant manifold $M$ is attractive (repulsive). Some illustrative examples of the invariant manifolds, such as equilibria, periodic solution, stable and unstable manifolds, other invariant manifold are pre...

  14. Chemistry of sex attraction.

    OpenAIRE

    Roelofs, W L

    1995-01-01

    The chemical communication system used to attract mates involves not only the overt chemical signals but also indirectly a great deal of chemistry in the emitter and receiver. As an example, in emitting female moths, this includes enzymes (and cofactors, mRNA, genes) of the pheromone biosynthetic pathways, hormones (and genes) involved in controlling pheromone production, receptors and second messengers for the hormones, and host plant cues that control release of the hormone. In receiving ma...

  15. Cytogenetic analysis of three species of Pseudacteon (Diptera, Phoridae) parasitoids of the fire ants using standard and molecular techniques

    OpenAIRE

    Mónica G. Chirino; Patricia J. Folgarait; Gilbert, Lawrence E; Silvia Lanzavecchia; Papeschi, Alba G.

    2009-01-01

    Pseudacteon flies, parasitoids of worker ants, are being intensively studied as potentially effective agents in the biological control of the invasive pest fire ant genus Solenopsis (Hymenoptera: Formicidae). This is the first attempt to describe the karyotype of P. curvatus Borgmeier, P. nocens Borgmeier and P. tricuspis Borgmeier. The three species possess 2n = 6; chromosomes I and II were metacentric in the three species, but chromosome pair III was subtelocentric in P. curvatus and P. tri...

  16. Interocular conflict attracts attention.

    Science.gov (United States)

    Paffen, Chris L E; Hessels, Roy S; Van der Stigchel, Stefan

    2012-02-01

    During binocular rivalry, perception alternates.between dissimilar images presented dichoptically. Since.its discovery, researchers have debated whether the phenomenon is subject to attentional control. While it is now clear that attentional control over binocular rivalry is possible, the opposite is less evident: Is interocular conflict (i.e., the situation leading to binocular rivalry) able to attract attention?In order to answer this question, we used a change blindness paradigm in which observers looked for salient changes in two alternating frames depicting natural scenes. Each frame contained two images: one for the left and one for the right eye. Changes occurring in a single image (monocular) were detected faster than those occurring in both images (binocular). In addition,monocular change detection was also faster than detection in fused versions of the changed and unchanged regions. These results show that interocular conflict is capable of attracting attention, since it guides visual attention toward salient changes that otherwise would remain unnoticed for longer. The results of a second experiment indicated that interocular conflict attracts attention during the first phase of presentation, a phase during which the stimulus is abnormally fused [added]. PMID:22167536

  17. Fingertip aura and interpersonal attraction.

    Science.gov (United States)

    Murstein, B I; Hadjolian, S E

    1977-06-01

    Concluding from our survey of the literature that fingertip auras (Kirlian effect) might be associated with interpersonal attraction, four hypotheses were advanced to test this assertion. It was hypothesized that individuals would respond with bigger auras to (1) opposite-sex photographers as compared to same-sex photographers, (2) to seductive opposite-sex photographers as opposed to normally behaving opposite-sex photographers, (3) to opposite-sex unknown peers as opposed to same-sex unknown peers, and (4) to liked as opposed to disliked same-sex persons. All hypotheses except (2) were supported. The second hypothesis was significant in a direction contrary to hypothesis. Fingertip auras are seen as a promising measurement device in the study of interpersonal attraction. PMID:16367230

  18. Impressions of Counselors as a Function of Counselor Physical Attractiveness

    Science.gov (United States)

    Carter, Jean A.

    1978-01-01

    Research assessed the effects of counselor physical attractiveness and inter-actions between attractiveness and counselor subject sex. It is suggested that sex of counselor and client may play a more important role independently and in conjunction with attractiveness than does attractiveness alone in influencing impressions and expectations.…

  19. Impact of botanical pesticides derived from Melia azedarach and Azadirachta indica on the biology of two parasitoid species of the diamondback moth

    NARCIS (Netherlands)

    Charleston, D.S.; Kfir, R.; Dicke, M.; Vet, L.E.M.

    2005-01-01

    The effect of two botanical pesticides was tested on two species of parasitoids, Cotesia plutellae and Diadromus collaris. Aqueous leaf extracts from the syringa tree, Melia azedarach and commercial formulations from the neem tree, Azadirachta indica, Neemix 4.5 were investigated in the laboratory a

  20. Assessment of Impact of Insecticides on Anagrus nilaparvatae (Pang et Wang) (Hymenoptera: Mymanidae), an Egg Parasitoid of the Rice Planthopper, Nilaparvata lugens (Hemiptera: Delphacidae)

    Science.gov (United States)

    The parasitoid Anagrus Nilaparvatae (Pang et Wang) (Hymenoptera: Mymanidae) is a major natural enemy of the rice planthopper Nilaparvata lugens (Hemiptera: Delphacidae). It plays an important role in the IPM of the rice planthopper. Contact and oral toxicity and residual effect of fourteen pesticide...

  1. U.S. Department of Energy Solar Decathlon: Challenging Students to Build Energy Efficient, Cost-Effective, and Attractive Solar-Powered Houses

    Energy Technology Data Exchange (ETDEWEB)

    Simon, J.

    2012-01-01

    The U.S. Department of Energy Solar Decathlon challenges collegiate teams to design, build, and operate solar-powered houses that are cost-effective, energy-efficient, and attractive. The winner of the competition is the team that best blends affordability, consumer appeal, and design excellence with optimal energy production and maximum efficiency. The paper discusses the solutions developed for the event. We believe that the solutions implemented for Solar Decathlon 2011 represent current trends and that by analyzing, critiquing, and exposing the solutions pursued, the industry can become better suited to address challenges of the future. Constructing a solar community using high-efficiency design and unique materials while remaining code compliant, safe, and effective results in solutions that are market relevant, important, and interesting to the industry as a whole.

  2. 6种饵料对小白鼠引诱作用的初步观察%Preliminary observation of the attracting effect of six mice baits

    Institute of Scientific and Technical Information of China (English)

    钟平生; 邓惠彩; 赵瑾; 郭国汉

    2011-01-01

    Objective To identify the most attractive mice baits for preparation of toxic baits. Methods The attracting effects of six types of bait (peanut, rice, potato, bean cake, fish bait, and cat food) on mice were determined in terms of the respective feeding coefficients. Results Mice showed different preferences for the six baits, of which potatoes and peanuts had the strongest attracting effects with feeding coefficients of 5.90 and 2.49, respectively, and average feeding rates of 60.71% and 25.61%, respectively. Bean cakes and rice followed with feeding coefficients of 1.08 and 1.16 and feeding rates of 14.49% and 11.94%, respectively. The attractive efficiency of fish baits and cat food were the lowest, with the feeding rates of 8.74% and 3.00%, respectively. Conclusion Potatoes and peanuts are the baits of choice when preparing poison baits for mice. Their attracting effects deteriorate with time and become the lowest beyond 48 hours. Furthermore, the nutritional balance or mixing of baits may be considered to improve palatability.%目的 寻找对小白鼠更具引诱力的饵料,为配制毒饵提供一定依据.方法 采用摄食系数测定6种不同饵料(花生、豆饼、稻谷、马铃薯、猫料、鱼饵)对小白鼠的引诱效果.结果 小白鼠对6种饵料的偏好性存在差异.其中马铃薯、花生对小白鼠的引诱效果最强,摄食系数为5.90和2.49,偏好性为优,平均取食率达60.71%和25.61%;豆饼和稻谷的引诱效果次之,摄食系数分别为1.08和1.16,偏好性也为优,取食率分别为14.49%和11.94%;鱼饵和猫料的引诱效果较弱,取食率分别仅为8.74%和3.00%,低于对照饵料——鼠粮的取食率(13.37%).结论 在配制鼠类毒饵时,可优先考虑更具引诱效果的马铃薯和花生;同时,随着投饵后时间的延长,持续引诱作用降低,其中以48 h后的减幅最大.此外,在研制灭鼠剂时,应考虑饵料的营养平衡或不同类型饵料的交替使用,以提高诱饵的适口性.

  3. Efeitos de atrativos e repelentes sobre o comportamento da abelha (Apis mellifera, l. Effect of attractants and repellents on the behavior of honey bees (Apis mellipera, L.

    Directory of Open Access Journals (Sweden)

    D.T. MALERBO-SOUZA

    1998-01-01

    Full Text Available O objetivo do presente ensaio foi testar diversas substâncias e verificar sua atratividade e repelência para abelhas, Apis mellifera, L. Para isso, foram realizados testes em discos próximos às colméias e em cana picada oferecida como alimentação para gado bovino confinado. Nos discos próximos à colméia, o produto mais atrativo foi Bee-Here e o mais repelente foi o óleo de citronela. No cocho para bovinos, o repelente mais efetivo foi n-octyl-acetato.The experiment aimed to study honey bee (Apis mellifera attractants and repellents in vitro and on chopped sugar cane for bovine feeding. Tests were performed on plates located near to the hives and on bovine-hods. On plates, Bee-Here® was the most attractive and citronela oil the most repellent. On bovine-hods the most effective was n-octyl-acetate.

  4. Biology of Habrobracon gelechiae (Hymenoptera: Braconidae), as a parasitoid of the obliquebanded leafroller (Lepidoptera: Tortricidae).

    Science.gov (United States)

    Daane, Kent M; Wang, Xingeng; Duerr, Sean S; Kuhn, Emily J; Son, Youngsoo; Yokota, Glenn Y

    2013-02-01

    Habrobracon gelechiae Ashmead (Hymenoptera: Braconidae) was studied as a parasitoid of the obliquebanded leafroller, Choristoneura rosaceana (Harris) (Lepidoptera: Tortricidae) in California pistachio (Pistacia vera L.) orchards. Ovipositional behavior, adult longevity and fecundity, and the effects of temperature on developmental time and survival were determined. Habrobracon gelechiae develops as a gregarious, ectoparasitic idiobiont on late-instar C. rosaceana larvae. At 25°C, adult female wasps survived longer when provided honey and water (35.4 ± 4.9 d) or honey, water, and host larvae (34.4 ± 2.4 d) than when provided water (8.9 ± 1.1 d) or no food (5.9 ± 0.8 d). Over the adult lifespan, females parasitized 20.6 ± 2.1 hosts and deposited 228.8 ± 24.6 eggs. The intrinsic rate of increase was 0.24, the mean generation time was 18.15 d, and the double time 2.88 d. At constant temperatures, H. gelechiae successfully developed (egg to adult) from 15 to 35 °C. The developmental rate was fit to a nonlinear model, providing estimates of the parasitoid's lower (10.5 °C), upper (36.0 °C), and optimal (33.3 °C) development temperatures. Based on a linear model, 155 degree days were estimated for egg to adult eclosion. Temperature-dependent nonlinear model of survival showed similar shape with the model of development rate. The wasp developed under two diurnal temperature regimes, with 31.0 ± 13.3% survival at low (4-15 °C) and 63.0 ± 11.4% survival at high (15-35 °C) temperature regimes. The results are discussed with respect to H. gelechiae potential as a parasitoid of C. rosaceana in California's San Joaquin Valley. PMID:23339791

  5. Relações interespecíficas entre parasitoides nativos de moscas-das-frutas e o braconídeo exótico Diachasmimorpha longicaudata em frutos de 'umbu-cajá' Interespecific relations between native parasitoids of fruit flies and exotic braconid Diachasmimorpha longicaudata in fruits of 'umbu-cajá'

    Directory of Open Access Journals (Sweden)

    Zuzinaide Vidal Bomfim

    2010-02-01

    Full Text Available Espécies de vespas parasitoides (Hymenoptera: Braconidae são importantes agentes de controle biológico de moscas-das-frutas (Diptera: Tephritidae. Este trabalho teve por objetivo conhecer os efeitos da liberação e as relações de competitividade interespecífica do parasitoide exótico Diachasmimorpha longicaudata Ashmead sobre o complexo de parasitoides nativos de moscas-das-frutas associado a frutos de 'umbu-cajá' (Spondias spp. na região do Recôncavo Baiano. Entre os meses de abril e julho de 2006, 8.955 frutos (192,93kg foram coletados antes e após (24 e 48 horas a liberação de 9.600 fêmeas de D. longicaudata em campo. Obteve-se um total de 8.724 pupários de Tephritidae, dos quais emergiram 3.963 adultos de Anastrepha obliqua (Macquart e 1.115 parasitoides. A maior frequência relativa foi de Doryctobracon areolatus (Szépligeti, seguida por Asobara Anastrephae (Muesebeck e Utetes Anastrephae (Viereck. Após 24 e 48 horas da liberação do parasitoide exótico D. longicaudata em campo, constatou-se que o índice de parasitismo total aumentou de 15,86 para 20,4 e 45,19%, respectivamente. Assim, observou-se que a liberação da espécie exótica D. longicaudata não apresenta efeitos negativos na ocorrência dos parasitoides nativos e contribui para complementar o controle biológico natural de A. obliqua em frutos de 'umbu-cajá', nas condições deste estudo.Wasps parasitoid species (Hymenoptera: Braconidae are fruit flies (Diptera: Tephritidae biological control important agents. This study aimed to know the effects of the release and interspecific competitive relationships of the exotic parasitoid Diachasmimorpha longicaudata Ashmead (Hymenoptera: Braconidae on the native parasitoid complex of fruit flies in Spondias spp. in the region of Recôncavo Baiano. From April to July of 2006, 8.955 fruits (192.93kg were collected before and after (24 and 48 hours release of 9.600 females of D. longicaudata. Exactly 8.724 Tephritidae

  6. A review of aphid parasitoids (Hym., Braconidae, Aphidiinae) of Turkey

    Czech Academy of Sciences Publication Activity Database

    El-Mali, M. U.; Starý, Petr; Sahbaz, A.; Zsemerci, F.

    2004-01-01

    Roč. 14, č. 2 (2004), 355-370. ISSN 1110-1768 R&D Projects: GA AV ČR(CZ) IBS5007102; GA AV ČR(CZ) IAA6007105 Institutional research plan: CEZ:AV0Z5007907 Keywords : review * aphid parasitoids * Turkey Subject RIV: EG - Zoology

  7. Foraging behavior of egg parasitoids exploiting chemical information

    NARCIS (Netherlands)

    Fatouros, N.E.; Dicke, M.; Mumm, R.; Meiners, T.; Hilker, M.

    2008-01-01

    Female parasitic wasps seek hosts for their offspring often in a dynamic environment. Foraging egg parasitoids rely on a variety of chemical cues originating from the adult host, host products, or the host plant rather than from the attacked host stage¿the insect egg itself. Besides pupae, insect eg

  8. Fire ant microsporidia acquired by parasitoid flies of fire ants

    Science.gov (United States)

    The microsporidium Kneallhazia (formerly Thelohania) solenopsae and parasitoid flies in the genus Pseudacteon are natural enemies of the invasive fire ant, Solenopsis invicta. Pseudacteon flies oviposit into adult fire ants, where maggots that eclose from eggs migrate to the ants’ head, pupate, and...

  9. Foraging under incomplete information: parasitoid behaviour and community dynamics

    NARCIS (Netherlands)

    Vos, M.

    2001-01-01

    This thesis describes research on multitrophic interactions between parasitoids, herbivores and plants. These are all involved in a dynamic game of hide-and-seek. Insect herbivores may occur in different spatial distributions across plants. Some species occur in local clusters, while others have a m

  10. Sugar convertibility in the parasitoid Cotesia glomerata (Hymenoptera: Braconidae)

    NARCIS (Netherlands)

    Hausmann, C.; Wäckers, F.L.; Dorn, S.

    2005-01-01

    Lack of suitable sugar sources for adult parasitic wasps is an important cause of failure in biological control programs, but the metabolic constraints of sugar feeding are poorly understood. Here we investigated the suitability of 11 naturally occurring sugars as energy sources for the parasitoid C

  11. Identification and evaluation of Trichogramma parasitoids for biological pest control

    NARCIS (Netherlands)

    Silva, I.M.M.S.

    1999-01-01

    Egg parasitoids of the genus Trichogramma are used as biological control agents against lepidopterous pests. From the 180 species described world-wide, only 5 have large scale application. The development of better methods to select other Trichogramma species/strains is necessary for a more effectiv

  12. Venom of Parasitoid Pteromalus puparum Impairs Host Humoral Antimicrobial Activity by Decreasing Host Cecropin and Lysozyme Gene Expression

    Science.gov (United States)

    Fang, Qi; Wang, Bei-Bei; Ye, Xin-Hai; Wang, Fei; Ye, Gong-Yin

    2016-01-01

    Insect host/parasitoid interactions are co-evolved systems in which host defenses are balanced by parasitoid mechanisms to disable or hide from host immune effectors. Here, we report that Pteromalus puparum venom impairs the antimicrobial activity of its host Pieris rapae. Inhibition zone results showed that bead injection induced the antimicrobial activity of the host hemolymph but that venom inhibited it. The cDNAs encoding cecropin and lysozyme were screened. Relative quantitative PCR results indicated that all of the microorganisms and bead injections up-regulated the transcript levels of the two genes but that venom down-regulated them. At 8 h post bead challenge, there was a peak in the transcript level of the cecropin gene, whereas the peak of lysozyme gene occurred at 24 h. The transcripts levels of the two genes were higher in the granulocytes and fat body than in other tissues. RNA interference decreased the transcript levels of the two genes and the antimicrobial activity of the pupal hemolymph. Venom injections similarly silenced the expression of the two genes during the first 8 h post-treatment in time- and dose-dependent manners, after which the silence effects abated. Additionally, recombinant cecropin and lysozyme had no significant effect on the emergence rate of pupae that were parasitized by P. puparum females. These findings suggest one mechanism of impairing host antimicrobial activity by parasitoid venom. PMID:26907346

  13. Venom of Parasitoid Pteromalus puparum Impairs Host Humoral Antimicrobial Activity by Decreasing Host Cecropin and Lysozyme Gene Expression.

    Science.gov (United States)

    Fang, Qi; Wang, Bei-Bei; Ye, Xin-Hai; Wang, Fei; Ye, Gong-Yin

    2016-01-01

    Insect host/parasitoid interactions are co-evolved systems in which host defenses are balanced by parasitoid mechanisms to disable or hide from host immune effectors. Here, we report that Pteromalus puparum venom impairs the antimicrobial activity of its host Pieris rapae. Inhibition zone results showed that bead injection induced the antimicrobial activity of the host hemolymph but that venom inhibited it. The cDNAs encoding cecropin and lysozyme were screened. Relative quantitative PCR results indicated that all of the microorganisms and bead injections up-regulated the transcript levels of the two genes but that venom down-regulated them. At 8 h post bead challenge, there was a peak in the transcript level of the cecropin gene, whereas the peak of lysozyme gene occurred at 24 h. The transcripts levels of the two genes were higher in the granulocytes and fat body than in other tissues. RNA interference decreased the transcript levels of the two genes and the antimicrobial activity of the pupal hemolymph. Venom injections similarly silenced the expression of the two genes during the first 8 h post-treatment in time- and dose-dependent manners, after which the silence effects abated. Additionally, recombinant cecropin and lysozyme had no significant effect on the emergence rate of pupae that were parasitized by P. puparum females. These findings suggest one mechanism of impairing host antimicrobial activity by parasitoid venom. PMID:26907346

  14. Venom of Parasitoid Pteromalus puparum Impairs Host Humoral Antimicrobial Activity by Decreasing Host Cecropin and Lysozyme Gene Expression

    Directory of Open Access Journals (Sweden)

    Qi Fang

    2016-02-01

    Full Text Available Insect host/parasitoid interactions are co-evolved systems in which host defenses are balanced by parasitoid mechanisms to disable or hide from host immune effectors. Here, we report that Pteromalus puparum venom impairs the antimicrobial activity of its host Pieris rapae. Inhibition zone results showed that bead injection induced the antimicrobial activity of the host hemolymph but that venom inhibited it. The cDNAs encoding cecropin and lysozyme were screened. Relative quantitative PCR results indicated that all of the microorganisms and bead injections up-regulated the transcript levels of the two genes but that venom down-regulated them. At 8 h post bead challenge, there was a peak in the transcript level of the cecropin gene, whereas the peak of lysozyme gene occurred at 24 h. The transcripts levels of the two genes were higher in the granulocytes and fat body than in other tissues. RNA interference decreased the transcript levels of the two genes and the antimicrobial activity of the pupal hemolymph. Venom injections similarly silenced the expression of the two genes during the first 8 h post-treatment in time- and dose-dependent manners, after which the silence effects abated. Additionally, recombinant cecropin and lysozyme had no significant effect on the emergence rate of pupae that were parasitized by P. puparum females. These findings suggest one mechanism of impairing host antimicrobial activity by parasitoid venom.

  15. Impact of terbufos on Cotesia flavipes, a parasitoid of Diatraea saccharalis

    International Nuclear Information System (INIS)

    The effect of terbufos on larvae of Diatraea saccharalis and its parasitoid, Cotesia flavipes was evaluated in the laboratory. Bioassays were conducted to determine the dose response of non-parasitized larvae of D. saccharalis feeding on artificial diet contaminated with terbufos. From the dose-response curve based on larval fresh weight, sublethal doses ranging from 1.32 ppm to 108 ppm of terbufos were selected for further studying the effect of the insecticide on both species. Both parasitized and non-parasitized larvae were exposed to the selected sublethal doses of terbufos in the diet. Consumption of the insecticide by the host resulted in mortality of the parasitoid, increased length of its larval and pupal periods, decreased adult fresh weight and changes in sex proportions. These negative effects were more severe as the dose of the insecticide increased. D. saccharalis was also affected by terbufos; larvae showed abnormalities, the length of the larval and pupal periods increased and the proportion of the females was reduced. In a preliminary greenhouse bioassay, only traces of terbufos or its metabolites were found in treated maize plants and in tissue of D. saccharalis larvae feeding on them. (author)

  16. 10种人工鱼礁模型对黑鲷幼鱼的诱集效果%Attraction effect of various artificial reef models on Sparus macrocephalus

    Institute of Scientific and Technical Information of China (English)

    周艳波; 蔡文贵; 陈海刚; 陈丕茂; 吕国敏; 贾晓平

    2011-01-01

    Artificial reef was used in marine ranch to improve the marine ecological environment and enhance the fishery resources. Attractive effects of artificial reef may be attributed to creating habitat, shelter and spawning ground for the various kinds of fish, therefore positively affect the breeding and growth of the fish. In recent years, artificial reef construction programs have been rapidly developed in China. However, the knowledge of the effect of artificial reef on marine ecological environment is limited. The present study aimed to determine the influence of materials, structure and combination on the attractive effects of the artificial reefs and therefore provide useful data and information for the development of artificial reef construction. In the present study, the effects of ten kinds of artificial reef models with different shapes, which have been deployed in Yangmeikeng reef area, on the behavioral responses of the fish Sparus macrocephalus and the fish attraction effects of the artificial reef models were analyzed and compared with those without the artificial reef model in the trough. The result showed that in the condition without the artificial reef model in the trough, the fish liked to stay in radius of the center trough area within 40 - 70 cm. while the fish are more dispersed in the trough. After the artificial model was put into the troughs, the fish liked to stay in radius of the center trough area within 20 - 50 cm while No. 1 reef-No. 8 reef were put into the trough, the fish liked to stay in radius of the center trough area within 10 -40 cm while No. 9 reef and No. 10 reef were put into the trough. The average occurring rate of the fish inside and near the reef areas all increased, while comparing fish occurring rates in artificial reef areas with or without artificial reef. The analysis results showed that all of the ten artificial reef models have obvious attraction effects on S. macrocephalus,especially for model NO. 10. Its attraction

  17. Comparison of effectiveness of various artificial reef materials for fish attraction%不同材料人工鱼礁生物诱集效果的比较

    Institute of Scientific and Technical Information of China (English)

    江艳娥; 陈丕茂; 林昭进; 方展强

    2013-01-01

    参考相关资料对比水泥类、油井类、舰船类及其他类型人工鱼礁对海洋生物诱集效果,探讨不同材料人工鱼礁在诱集效果上的差异.结果表明,人工鱼礁区生物诱集效果高出天然礁区(对照区)的比率达68.75%.不同材料类型人工鱼礁的生物诱集效果存在差异:水泥类人工鱼礁生物诱集效果高于天然礁区的比率为71.43%;油井类人工鱼礁生物诱集效果高于天然礁区的比率为50.00%;舰船类人工鱼礁生物诱集效果高于天然礁区的比率为100.00%;其他类人工鱼礁生物诱集效果高于天然礁区的比率为80.00%.研究资料分析表明人工鱼礁的建设,需要更多地结合海洋物理、海洋化学、海洋生物等方面的知识,以提高人工鱼礁对海洋生物的增殖效果,促进其生态效益、经济效益和社会效益共同提高.%Analyzed the effectiveness of fish attraction on artificial reef of concrete,oil jetty,vessel and other materials,differences of fish attraction on these artificial reefs versus natural reefs (control sites) have been recognized.68.75% of all these analyzed artificial reefs have higher records of fish attraction than that in natural reefs.The record is 71.43% in concrete artificial reefs,50.00% in oil jetty artificial reefs,100% in vessel artificial reefs,80.00% in other material artificial reefs.In conclusion,the following advices could favor the fish attraction:smallscale isolated artificial reefs,concrete material with much holes and shade if possible and high variation of model appearance.Not only these factors,but also factors of physic,chemical and biology would work together on artificial reefs to attract marine organisms for ecological,economic and social benefits.

  18. Susceptibility of the Parasitoid Phymastichus coffea LaSalle (Hymenoptera: Eulophidae) to Beauveria bassiana under laboratory conditions; Susceptibilidad del parasitoide Phymastichus coffea LaSalle (Hymenoptera:Eulophidae) a Beauveria bassiana en condiciones de laboratorio

    Energy Technology Data Exchange (ETDEWEB)

    Castillo, Alfredo; Gomez, Jaime; Infante, Francisco [El Colegio de la Frontera Sur (ECOSUR), Chiapas (Mexico). Dept. de Entomologia Tropical], e-mail: acastill@ecosur.mx, e-mail: jgomez@ecosur.mx, e-mail: finfante@ecosur.mx; Vega, Fernando E. [United States Department of Agriculture (USDA), Beltsville, MD (United States). Agricultural Research Service. Sustainable Perennial Crops Lab.], e-mail: fernando.vega@ars.usda.gov

    2009-09-15

    The coffee berry borer, Hypothenemus hampei (Ferrari) (Coleoptera: Curculionidae), is the most important coffee pest worldwide. Beauveria bassiana is a generalist entomopathogenic fungus widely used by coffee farmers to control this pest and Phymastichus coffea LaSalle (Hymenoptera: Eulophidae) is an African endo parasitoid of H. hampei adults, recently imported to several Latin American and Caribbean countries to aid in the coffee berry borer control. The objective of this study was to determine if B. bassiana is detrimental to P. coffea. The susceptibility of the parasitoid was evaluated in terms of adult survivorship, mean lethal concentration (LC{sub 50}), mean lethal time (LT{sub 50}), reproduction and immature mortality. The main effect of the fungus resulted in reduction of adult longevity and mortality of 100% for immature stages of this parasitoid. The LC{sub 50} for adults was 0.11% equivalent to 9.53 x 10{sup 7} conidia/ml of B. bassiana and a LT{sub 50} of 29.4 h, equivalent to reduction of 22% of its normal longevity as an adult. P. coffea was capable of disseminating spores of B. bassiana to non-infected H. hampei adults, which could indirectly cause the death of its own progeny. These results could be valuable when considering the use of both organisms in the field, especially in an integrated pest management program. (author)

  19. A novel design and driving strategy for a hybrid electric machine with torque performance enhancement both taking reluctance and electromagnetic attraction effects into account

    International Nuclear Information System (INIS)

    A novel design, the hybrid electric machine, that owns improved competence for the output torque regulation as well as enlarged power density comparing to the conventional brushless machines by making use of the simultaneous performance overlapping concept based on magnetism is proposed in this paper. The developed design concept is focused on electric machine structure and its counterpart drive for applying two main magnetic-power transmitting paths by combination of both features of magnetic tendencies of flux generation that may flow in the path with minimum reluctance and direction owning the electromagnetic motive attraction. The verifications demonstrate that the outputted torque owns effective improvement by the presented concept of the electric machine based on the equivalent 3-hp frame than the conventional brushless motors

  20. Stereoselective Chlorination and Bromination of Enamides and Enamines via an Electrostatic Attraction Effect Using (1,1-Diacetoxyiodo)benzene and a Halide Source.

    Science.gov (United States)

    Xing, Linlin; Li, Chunbao

    2015-10-16

    The direct chlorination and bromination of (E)-enamines and (Z)-enamides to the corresponding (Z)-configurated α-chloroenamines, α-bromoenamines, and α-chloroenamides have been realized using NiCl2·6H2O or tetrabutyl ammonium bromide as a halide source and (1,1-diacetoxyiodo)benzene as an oxidant. The high stereoselective reactions which produce products with only (Z)-configurations can be attributed to the structure of the intermediates, the conformations of which are controlled by the electrostatic attractions between the positively charged nitrogen atoms and the oxygen atoms of the carbonyl group. This type of electrostatic effect has never been reported in olefin halogenations. For this reason, the three-membered bromonium ion is only a minor intermediate in the enamine bromination pathway. These methods open pathways to prepare α-chloroenamines and α-chloroenamides, which are not accessible via the currently used methods. PMID:26421836

  1. Effect of attract and kill formulations and application rates on trap catches of European pine shoot moth (Lepidoptera: Tortricidae) and shoot damage in Scots pine saplings.

    Science.gov (United States)

    Sukovata, Lidia; Kolk, Andrzej; Cieślak, Marek

    2004-10-01

    Attract and kill technology was tested for management of European pine shoot moth, Rhyacionia buoliana (Denis & Schiffermüller), in 4-6-yr-old Scots pine, Pinus sylvestris L., plantations managed by Jablonna and Pultusk Forest Districts, Poland. In 2001, two formulations based on ricinoleic acid and hydrocarbon fraction (petroleum jelly) in combination with (E)-9-dodecenyl acetate, the sex pheromone of the pine shoot moth; permethrin as a contact insecticide; and Tinuvin UV absorber were used. In 2002, different formulations and application rates of the attracticide based on petroleum jelly were tested. Significantly reduced trap catches occurred in plots treated with three attracticide formulations [Rhykil-1 (with Tinuvin UV absorber), Rhykil-2 (with a new UV absorber, 3,3'-dihydroxy-2,2'-bipyridyl), and Rhykil-3 (without the insecticide)] at 3,000 droplets per hectare in comparison with those in control plots, suggesting that all formulations were highly effective. Significantly lower catches than in control plots also were observed when Rhykil-1 was applied at 1000, 2,000, and 3,000 droplets per hectare. However, only slight reduction of shoot damage in treated plots was observed in both experiments. The formulation without the insecticide had similar efficacy to that of the formulation combined with the insecticide. In 2003, the Rhykil-2 attracticide was tested at 250, 500, and 1000 droplets per hectare. Although there were no significant differences in trap catches between treated and control plots, shoot damage level was reduced substantially in all treated plots. These results suggest that attract and kill technology may be used at rates lower than 1000 droplets per hectare for management of R. buoliana; however, its "kill" effect should be confirmed in further studies. PMID:15568351

  2. Sunflower stem weevil and its larval parasitoids in native sunflowers: Is parasitoid abundance and diversity greater in the US Southwest?

    Science.gov (United States)

    Sunflower stem weevils (Cylindrocopturus adspersus) and their larval parasitoids were collected from stems of four native sunflower species (Helianthus annuus, H. nuttallii, H. pauciflorus, and H. petiolaris) from 147 sites across eight states in 2003 and 2005. Native H. annuus constituted the major...

  3. Biological Control of Solenopsis Fire Ants by Pseudacteon Parasitoids: Theory and Practice

    Directory of Open Access Journals (Sweden)

    Lloyd W. Morrison

    2012-01-01

    Full Text Available Pseudacteon parasitoids are potential biocontrol agents of invasive Solenopsis fire ants. Pseudacteon species that parasitize the invasive S. invicta Buren and S. richteri Forel have been introduced to, and naturally dispersed across, the southeastern USA, although there is no evidence yet that Solenopsis host ant populations have decreased. The ability of introduced Pseudacteon species to regulate Solenopsis populations will depend upon the relative importance of top-down effects in the recipient communities. In this paper, I examine the characteristics of the Pseudacteon/Solenopsis parasitoid/host system and evaluate the extent to which research findings are consistent with top-down control. Laboratory and field experiments evaluating Solenopsis population regulation have been equivocal, and overall the available evidence provides little support for strong top-down effects in this system. Competitive exclusion may occur among introduced Pseudacteon species, and future efforts at biological control are likely to be more efficacious if they focus on other types of natural enemies.

  4. Parasitoids and competitors influence colony-level responses in the red imported fire ant, Solenopsis invicta

    Science.gov (United States)

    Mehdiabadi, Natasha J.; Kawazoe, Elizabeth A.; Gilbert, Lawrence E.

    2004-11-01

    Social insect colonies respond to challenges set by a variable environment by reallocating work among colony members. In many social insects, such colony-level task allocation strategies are achieved through individual decisions that produce a self-organized adapting group. We investigated colony responses to parasitoids and native ant competitors in the red imported fire ant (Solenopsis invicta). Parasitoid flies affected fire ants by decreasing the proportion of workers engaged in foraging. Competitors also altered colony-level behaviours by reducing the proportion of foraging ants and by increasing the proportion of roaming majors, whose role is colony defence. Interestingly, the presence of both parasitism and competition almost always had similar effects on task allocation in comparison to each of the biotic factors on its own. Thus, our study uniquely demonstrates that the interactive effect of both parasitism and competition is not necessarily additive, implying that these biotic factors alter colony behaviour in distinct ways. More generally, our work demonstrates the importance of studying the dynamics of species interactions in a broader context.

  5. Susceptibility of the Parasitoid Phymastichus coffea LaSalle (Hymenoptera: Eulophidae) to Beauveria bassiana under laboratory conditions

    International Nuclear Information System (INIS)

    The coffee berry borer, Hypothenemus hampei (Ferrari) (Coleoptera: Curculionidae), is the most important coffee pest worldwide. Beauveria bassiana is a generalist entomopathogenic fungus widely used by coffee farmers to control this pest and Phymastichus coffea LaSalle (Hymenoptera: Eulophidae) is an African endo parasitoid of H. hampei adults, recently imported to several Latin American and Caribbean countries to aid in the coffee berry borer control. The objective of this study was to determine if B. bassiana is detrimental to P. coffea. The susceptibility of the parasitoid was evaluated in terms of adult survivorship, mean lethal concentration (LC50), mean lethal time (LT50), reproduction and immature mortality. The main effect of the fungus resulted in reduction of adult longevity and mortality of 100% for immature stages of this parasitoid. The LC50 for adults was 0.11% equivalent to 9.53 x 107 conidia/ml of B. bassiana and a LT50 of 29.4 h, equivalent to reduction of 22% of its normal longevity as an adult. P. coffea was capable of disseminating spores of B. bassiana to non-infected H. hampei adults, which could indirectly cause the death of its own progeny. These results could be valuable when considering the use of both organisms in the field, especially in an integrated pest management program. (author)

  6. Ação transovariana de lufenuron (50 g/l sobre adultos de Spodoptera Frugiperda (j. e. smith (Lepidoptera: Noctuidae e seu efeito sobre o parasitóide de ovos Trichogramma pretiosum Riley (Hymenoptera: Trichogrammatidae Transovarian action of lufenuron on adults of Spodoptera frugiperda (J. E. Smith (Lepidoptera: Noctuidae and its effect on the parasitoid Trichogramma pretiosum Riley (Hymenoptera: Trichogrammatidae

    Directory of Open Access Journals (Sweden)

    Dirceu Pratissoli

    2004-02-01

    Full Text Available Avaliaram-se a ação transovariana do lufenuron em Spodoptera frugiperda e sua seletividade ao parasitóide de ovos Trichogramma pretiosum. Casais da praga foram isolados em gaiolas de PVC e alimentados com solução de mel a 10% na testemunha, e nos outros tratamentos, foi adicionado à solução de mel o regulador de crescimento de insetos Match® CE nas proporções de 12,5; 15,0 e 17,5 g i.a/l. Para verificação da ação transovariana, diariamente foram coletadas as posturas, contado o número de ovos e, posteriormente, o número de larvas eclodidas. Quarenta ovos provenientes de cada tratamento foram colados em cartelas de papel (cartolina e expostos ao parasitismo, dentro de tubos de vidro de 1,0 x 3,5 cm, contendo uma fêmea de T. pretiosum no seu interior. Cartelas contendo 40 ovos de S. frugiperda foram imersas em soluções de lufenuron com a mesma concentração dos tratamentos anteriores e, posteriormente, expostas ao parasitismo por T. pretiosum. O lufenuron afetou consideravelmente a viabilidade dos ovos de S. frugiperda. Pelos resultados obtidos nos ensaios, relativos ao parasitóide, demonstram-se a seletividade do regulador de crescimento lufenuron e a possibilidade de sua utilização em programas de Manejo Integrado, juntamente com o parasitóide de ovos T. pretiosum.The transovarian action of insect growth regulator lufenuron in Spodoptera frugiperda (Lepidoptera: Noctuidae and its effects on the egg parasitoid Trichogramma pretiosum (Hymenoptera: Trichogrammatidae, were evaluated. Pest couples were isolated in PVC's cages and provided with 10% honey solution as control. In the others treatments, the honey solution was mixed with the insect growth regulator Match® CE using the following concentrations of 12.5; 15.0 and 17.5 g i.a./l. For verification of the transovarian action, the eggs were collected daily, with the number of the hatched larvae being subsequently counted. Forty eggs from each treatment were fixed in

  7. Parasitoids and Parasitoids and Predators of Ips typographus (L. in Unmanaged and Managed Spruce Forests in Natural Park Apuseni, Romania

    Directory of Open Access Journals (Sweden)

    Ciprian George FORA

    2014-06-01

    Full Text Available The last time span, of protected areas of forest ecosystems established raise of a variety of problems regarding frequency and intensity of the attack carried out by the rich pest complex affecting the trees’ state of health. The current legislation forbids the application of pests control measures which can affect the biodiversity of these ecosystems. Species belonging to the useful entomofauna may interfere in the decrease of pest populations in these areas. The study of the parasitoid and predator complex has thus become a very topical research field, and these type of studies were carried out in Natural Park Apuseni, Romania. With the aim to identify present parasitoids and predators, 24 spruce logs provided from physiological weakened trees of 20-25 cm diameter and 1 m length were placed in 6 locations, in order to be populated by the spruce bark beetle Ips typographus (Linnaeus as a trophic base of useful insect species. After its infestation the wood material was put in eclectors and analyzed weekly for the spruce bark beetle Ips typographus, its parasitoids and predators. After examining collected biological material, 6 parasitoid species were identified which determined a 4.8% parasitization in unmanaged and 2.3% parasitization in managed forests. The best represented Hymenopteran parasitoids were Roptrocerus ylophagorum (Ratzeburg and Rhopalicus tutela (Walker. The found Coleopteran predators were from 12 species, which belong to 4 families. The most captures were of the species Nemosoma elongatum (Linnaeus, representing 50.3% of the total captured predators and Rhizophagus cribratus (Gyllenhaal, representing 9.5% of the captures.

  8. Attractions between charged colloids at water interfaces

    OpenAIRE

    Oettel, M.; Dominguez, A; Dietrich, S.

    2005-01-01

    The effective potential between charged colloids trapped at water interfaces is analyzed. It consists of a repulsive electrostatic and an attractive capillary part which asymptotically both show dipole--like behavior. For sufficiently large colloid charges, the capillary attraction dominates at large separations. The total effective potential exhibits a minimum at intermediate separations if the Debye screening length of water and the colloid radius are of comparable size.

  9. Hymenopteran parasitoids of the ant-eating spider Zodarion styliferum (Simon (Araneae, Zodariidae

    Directory of Open Access Journals (Sweden)

    Stanislav Korenko

    2013-02-01

    Full Text Available Calymmochilus dispar Bouček & Andriescu (Hymenoptera, Eupelmidae and Gelis apterus (Pontoppidan (Hymenoptera, Ichneumonidae are newly recorded as parasitoids of the ant-eating spider Zodarion styliferum (Simon (Araneae, Zodariidae. The larvae of both parasitoid species fed on juvenile spiders. The final instar larva and pupa of C. dispar and the male of G. apterus are described for the first time. Both species represent new distribution records for Portugal. The biology and host associations of the parasitoids are discussed.

  10. Absence of Transgenerational Phenotypic Plasticity in Fecundity in the Parasitoid Anagrus erythroneurae (Hymenoptera: Mymaridae)

    OpenAIRE

    Andreazza, Felipe; Rosenheim, Jay A.

    2015-01-01

    To improve biological pest control, we would like to understand the main factors that limit the reproductive success of key biological control agents, including parasitoid wasps. Previous research with proovigenic parasitoids in the genus Anagrus collected from multiple field sites revealed positive correlations between parasitoid fecundity and local host density. In this article, we test whether this variation in fecundity is a reflection of transgenerational phenotypic plasticity. We expose...

  11. Behavioral Strategies of Phorid Parasitoids and Responses of Their Hosts, the Leaf-Cutting Ants

    OpenAIRE

    Elizalde, Luciana; Folgarait, Patricia Julia

    2012-01-01

    Host-searching and oviposition behaviors of parasitoids, and defensive responses of the hosts, are fundamental in shaping the ecology of host-parasitoid interactions. In order to uncover key behavioral features for the little known interactions between phorid parasitoids (Diptera: Phoridae) and their leaf-cutting ant hosts (Formicidae: Attini), host-related behavioral strategies (i.e., host searching and oviposition) for 13 phorid species, and host defensive responses (i.e., hitchhikers and p...

  12. Parasitoids of Leafminers (Diptera: Agromyzidae) from Southeast Turkey with 3 New Records

    OpenAIRE

    ÇIKMAN, Emine; BEYARSLAN, Ahmet; CİVELEK, Hasan Sungur

    2006-01-01

    This study was carried out in order to determine parasitoid species of the family Agromyzidae (Diptera) in Diyarbakır and Mardin provinces during 2002-2004. Infested leaves with leafminer larvae were collected from both cultivated and non-cultivated plants twice a month. The adult parasitoids were obtained by rearing from infested leaves in the laboratory. Five parasitoid species belonging to the Braconidae (Hymenoptera) were found. These species, Bracon kirgisorum Telenga, 1936, Opius basali...

  13. Shifting preference between oviposition vs. host-feeding under changing host densities in two aphelinid parasitoids

    DEFF Research Database (Denmark)

    Yang, Nian-Wan; Ji, Lu-Lu; Lövei, Gabor L;

    2012-01-01

    Destructive host-feeding is common in hymenopteran parasitoids. Such feeding may be restricted to host stages not preferred for oviposition. However, whether this is a fixed strategy or can vary according to resource levels or parasitoid needs is less clear. We tested the trade-off between host....... The balance between reserving optimal hosts for oviposition or using them for host-feeding depended on parasitoid life history and the availability of host resources....

  14. Insects Can Count: Sensory Basis of Host Discrimination in Parasitoid Wasps Revealed

    OpenAIRE

    Sara Ruschioni; van Loon, Joop J. A.; Smid, Hans M; Joop C van Lenteren

    2015-01-01

    The solitary parasitoid Leptopilina heterotoma is one of the best studied organisms concerning the ecology, behaviour and physiology of host discrimination. Behavioural evidence shows that L. heterotoma uses its ovipositor to discriminate not only between parasitized and unparasitized Drosophila melanogaster larvae, but also to discriminate between hosts with different numbers of parasitoid eggs. The existing knowledge about how and when the parasitoid marks the host motivated us to unravel t...

  15. Use of gamma radiation for the economic production of an egg parasitoid, Trichogramma chilonis (Ishii)

    International Nuclear Information System (INIS)

    Sugarcane is an important cash crop of irrigated areas of Pakistan. Average yield per hectare is very low as compared to other cane growing countries of the world. Amongst the factors responsible for this low yield are insect pests as the major limiting factor. Insect pests have devastating effects on production of this crop. Conservative estimates indicate that insect pests reduce crop yield up to 80%, while 20% is common. It has always been difficult to control borer pests with insecticides due to the concealed feeding habits of the damaging stage, i.e. larvae. Moreover, insecticides are expensive and hazardous, cause environmental pollution and insect pests become resistant. Interest has resurfaced in using the biological control, which has long been recognised as an important tool in suppressing insect pests. The beneficial insects have been successfully manipulated with a variety of augmentation and conservation strategies. However, production of natural enemies in an efficient and economical way is a prerequisite for any biological control programme. Considerable technological advances have been made in mass-rearing of parasitoids and predators for augmentative biological management of the pests. Irradiation may play a significant role in the economical production of natural enemies. The studies reported here were designed specifically to evaluate the feasibility of using nuclear techniques for efficient and economical production of the egg parasitoid, Trichogramma chilonis, a polyphagous parasitoid of lepidopteran pests. Eggs of Angoumois grain moth were obtained from the moths reared in the laboratory at 25±2 deg. C in 2.5-liter glass jars. For this purpose, a large numbers of 1- to 2-day old adults were collected from stock cultures and placed in inverted 1-liter plastic jars with screen bottoms. Eggs that fell through screen bottoms were collected by sifting them with the help of a 70- mesh screen. The egg cards were prepared having approx. 2,000 eggs

  16. Biocontrol potential of Lariophagus distinguendus (Hymenoptera: Pteromalidae) against Sitophilus granarius (Coleoptera: Curculionidae) at low temperatures: reproduction and parasitoid-induced mortality.

    Science.gov (United States)

    Hansen, Lise Stengård

    2007-06-01

    Lariophagus distinguendus Forster (Hymenoptera: Pteromalidae) has been suggested as a biological control agent against the granary weevil, Sitophilus granarius (L.), in grain stores. Information on the effect of low temperatures prevailing in grain stores is necessary to be able to predict the potential of this parasitoid against S. granarius in temperate regions, where grain is cooled with ambient air to achieve safe storage conditions. The influence of constant temperatures of 16, 18, and 20 degrees C on life table parameters and parasitoid-induced mortality (PIM) was investigated in the laboratory. L. distinguendus is able to develop and reproduce at temperatures as low as 16 degrees C. The intrinsic rate of natural increase, rm, was 0.0182, 0.0222, and 0.0792 d(-1) at 16, 18, and 20 degrees C, respectively. The proportion of hosts killed due to parasitoid-induced mortality was highest at 20 degrees C. At this temperature, it amounted to 70% of the total mortality exerted by the parasitoid; at 18 and 16'C, it was 57 and 42% of the total, respectively. L. distinguendus is a promising biocontrol agent for grain stores in temperate regions because it is able to develop and reproduce at temperatures down to 16 degrees C; its development is quicker than that of its host, estimated from the literature; and it kills many hosts in addition to those used for reproduction. PMID:17598568

  17. Impact of αAI-1 expressed in genetically modified cowpea on Zabrotes subfasciatus (Coleoptera: Chrysomelidae) and its parasitoid, Dinarmus basalis (Hymenoptera: Pteromalidae).

    Science.gov (United States)

    Lüthi, Christoph; Alvarez-Alfageme, Fernando; Romeis, Jörg

    2013-01-01

    Genetically modified (GM) cowpea seeds expressing αAI-1, an α-amylase inhibitor from the common bean, have been shown to be immune against several bruchid species. Effective control of such pests by growing GM cowpea could promote the spread of bruchid species that are αAI-1 tolerant. Consequently, the sustainability of bruchid pest control could be increased by combining GM seeds and hymenopteran parasitoids. However, there are concerns that αAI-1 could interfere with the biological control provided by parasitoids. Here, we assessed the impact of GM cowpea seeds expressing αAI-1 on the αAI-1-tolerant bruchid Zabrotes subfasciatus and its parasitoid Dinarmus basalis. αAI-1 in cowpea seeds did not increase resistance to Z. subfasciatus or affect the mortality rate of Z. subfasciatus larvae. Parasitism of Z. subfasciatus by D. basalis and fitness of D. basalis offspring were not affected by the presence of αAI-1. Thus, αAI-1-expressing cowpeas and parasitoids should be compatible for the control of bruchid pests. PMID:23840776

  18. Impact and Selectivity of Insecticides to Predators and Parasitoids

    Directory of Open Access Journals (Sweden)

    Flávio Lemes Fernandes

    2010-04-01

    Full Text Available Problems with the use of insecticides has brought losses, such as, negative impact on natural enemies. When these beneficial insects reduce cause the eruption of pests and resurgence it’s more common. Thus principles of conservation these arthropods are extremely important in the biological natural control of pests, so that these enemies may present a high performance. Because of the negative impacts caused by insecticides on agriculture and their harmful effects on natural enemies, the objective of this article is to approach two important subjects, divided into three parts. Part I relates to the description of the main crop pests and their natural enemies; Part II involves the impact of insecticides on predators and parasitoids and Part III focuses on the selectivity of several groups of insecticides to natural enemies. Before spraying insecticides, it is necessary to choose a product that is efficient to pests and selective to natural enemies. So, it is indispensable to identify correctly the groups and species of natural enemies, since insecticides have an impact on their survival, growth, development, reproduction (sexual ratio, fecundity, longevity and fertility, and behavior (motility, orientation, feeding, oviposition and learning of insects. The mechanisms of toxicity and selectivity of insecticides are related to the properties of higher or lower solubility and molecular weight. Besides, characteristics of the cuticular composition of the integument of natural enemies are extremely important in the selectivity of a product or the tolerance of a certain predator or parasitoid to this molecules.Impacto e Seletividade de Inseticidas para Predadores e ParasitóidesResumo.Dentre os problemas advindos do uso de inseticidas, a destruição de inimigos naturais é fator importante. Estes insetos benéficos podem reduzir problemas de erupção de pragas secundárias, ressurgência de pragas e manter a praga abaixo do nível de dano econ

  19. Role of plant volatiles in the search for a host by parasitoidDiglyphus isaea (Hymenoptera: Eulophidae).

    Science.gov (United States)

    Finidori-Logli, V; Bagnères, A G; Clément, J L

    1996-03-01

    Diglyphus isaea Walker is a larval ectoparasitoid used in biological pest control against the American serpentine leaf minerLiriomyza trifolii Burgess. We studied the parasitoid's host searching behavior, using olfactometric methods. Our data show that the parasitoids locate host larvae (a leafmining dipteran) on the basis of volatile signals released by the plant-host complex. FemaleD. isaea are strongly attracted to the odors arising from damaged bean plants, whereas they show practically no response to intact plants. The results of our chemical analyses showed that about 15 components were present, two of which,cis-3-hexen-1-ol and 4-hydroxy-4-methyl-2-pentanone, were present in significantly larger quantities in the leaf extracts from mined or damaged bean plants than in those from healthy plants. The damage inflicted by the host larvae on these plants triggers the release of larger amounts of these substances, which probably lead the parasites to their hosts. The compounds thus act as synomones. PMID:24227491

  20. Control of cabbage diamondback moth by integrating the sterile insect technique and parasitoids in Myanmar

    International Nuclear Information System (INIS)

    Full text: Mass rearing of DBM was carried out on cauliflower, cabbage, mustard and artificial diet. Pupae collection on aluminum foil was tested. Storage of pupae and larvae was carried out in 16 deg. C incubator and 5-10 deg. C refrigerator. Different doses of gamma radiation: 10Kr, 15Kr and 20Kr were tested to established the effective gamma radiation dose. Each one hundred cabbage plants were selected and marked for regular observations of DBM populations in control plots to assess the frequency distribution of DBM adult population in cabbage fields. DBM larvae were collected in control plots to assess the rate of DBM larvae with the parasitoid - Cotesia plutellae in fields. Mass rearing of DBM on cauliflower was better than rearing on cabbage, mustard and artificial diet. Pupae collection on cauliflower was better than those of cabbage, mustard and artificial diet. Pupae could be stored successfully for 2 weeks in 16 deg. C incubator and 5-10 deg. C refrigerator. DBM larvae reared on cauliflower could be stored for 7 days at 5-10 deg. c refrigerator. Radiation doses of 10Kr gave better results than 15 Kr and 20 Kr. 1-5 DBM adults were found in most of the plants during the season. Percentage of DBM larvae parasitised by the parasitoid - Cotesia plutellae was 30-40% in the field. (author)

  1. The role of geography and host abundance in the distribution of parasitoids of an alien pest.

    Science.gov (United States)

    Nováková, Petra; Holuša, Jaroslav; Horák, Jakub

    2016-01-01

    Chalcid wasps (Hymenoptera: Chalcidoidea) are probably the most effective and abundant parasitoids of the horse chestnut leaf miner (Cameraria ohridella), an alien pest in Europe that lacks specialized enemies. We studied how the species richness and abundance of chalcids are influenced by altitude, direction of an alien spread and host abundance of C. ohridella. We quantified the numbers and species richness of chalcid wasps and the numbers of C. ohridella that emerged from horse chestnut (Aesculus hippocastanum) leaf litter samples collected from 35 sites in the Czech Republic. Species richness of chalcids, which was considered an indicator of the possible adaptation of parasitoids to this alien host, was unrelated to C. ohridella abundance, direction of spread, or altitude. Chalcid abundance, which was considered an indicator of parasitism of the alien host, was strongly and positively related to C. ohridella abundance. Chalcid abundance was negatively related to direction of spread and positively related, although in a non-linear manner, to altitude. The relationship of chalcid abundance with direction of spread and altitude was weaker than that with C. ohridella abundance. The results provide evidence that biological control of the alien pest C. ohridella by natural enemies might develop in the future. PMID:26819849

  2. The role of geography and host abundance in the distribution of parasitoids of an alien pest

    Science.gov (United States)

    Nováková, Petra; Holuša, Jaroslav

    2016-01-01

    Chalcid wasps (Hymenoptera: Chalcidoidea) are probably the most effective and abundant parasitoids of the horse chestnut leaf miner (Cameraria ohridella), an alien pest in Europe that lacks specialized enemies. We studied how the species richness and abundance of chalcids are influenced by altitude, direction of an alien spread and host abundance of C. ohridella. We quantified the numbers and species richness of chalcid wasps and the numbers of C. ohridella that emerged from horse chestnut (Aesculus hippocastanum) leaf litter samples collected from 35 sites in the Czech Republic. Species richness of chalcids, which was considered an indicator of the possible adaptation of parasitoids to this alien host, was unrelated to C. ohridella abundance, direction of spread, or altitude. Chalcid abundance, which was considered an indicator of parasitism of the alien host, was strongly and positively related to C. ohridella abundance. Chalcid abundance was negatively related to direction of spread and positively related, although in a non-linear manner, to altitude. The relationship of chalcid abundance with direction of spread and altitude was weaker than that with C. ohridella abundance. The results provide evidence that biological control of the alien pest C. ohridella by natural enemies might develop in the future. PMID:26819849

  3. Adaptation of indigenous larval parasitoids to Tuta absoluta (Lepidoptera: Gelechiidae) in Italy.

    Science.gov (United States)

    Ferracini, Chiara; Ingegno, Barbara Letizia; Navone, Paolo; Ferrari, Ester; Mosti, Marco; Tavella, Luciana; Alma, Alberto

    2012-08-01

    Tuta absoluta (Meyrick) (Lepidoptera: Gelechiidae) is a serious threat to tomato (Solanum lycopersicum L.) crops in South America. In Europe, after its first detection in Spain in 2006, it rapidly spread through the Mediterranean basin, reaching Italy 2 yr later. The aim of our work was to find indigenous effective biological control agents and to evaluate their potential role in the control of larval populations of T. absoluta in controlled conditions. Nine species of larval parasitoids emerged from field-collected tomato leaves infested by T. absoluta. The most abundant, Necremnus near artynes (Walker) and Necremnus near tidius (Walker) (Hymenoptera: Eulophidae), were tested in laboratory parasitism trials. Furthermore, because the species N. artynes and N. tidius are each reported in literature as an ectoparasitoid of Cosmopterix pulchrimella Chambers (Lepidoptera: Cosmopterigidae) on upright pellitory plants, olfactometer bioassays were performed to assess the response of our parasitoids to the odors of tomato and pellitory leaves infested by T absoluta and C. pulchrimella, respectively, compared with healthy ones. Both Necremnus species showed good adaptation to the invasive pest, and we observed a high larval mortality of T. absoluta because of host feeding and parasitism. Even olfactory responses highlighted a preference of both wasps for tomato plants infested by the exotic pest. These preliminary results demonstrated a high suitability of these indigenous natural enemies for controlling T. absoluta. Further investigations are needed to confirm their role as potential biological agents in commercial tomato plantations. PMID:22928311

  4. Effect of tree species and end seal on attractiveness and utility of cut bolts to the redbay ambrosia beetle and granulate ambrosia beetle (coleoptera: Curculionidae: Scolytinae).

    Science.gov (United States)

    Mayfield, A E; Hanula, J L

    2012-04-01

    The redbay ambrosia beetle, Xyleborus glabratus Eichhoff, is a non-native invasive pest and vector of the fungus that causes laurel wilt disease in certain trees of the family Lauraceae. This study assessed the relative attractiveness and suitability of cut bolts of several tree species to X. glabratus. In 2009, female X. glabratus were equally attracted to traps baited with swampbay (Persea palustris (Rafinesque) Sargent) and camphortree (Cinnamomum camphora (L.) J. Presl), which were more attractive than avocado (Persea americana Miller), lancewood (Ocotea coriacea (Swartz) Britton), and sweetbay (Magnolia virginiana L.). These species were more attractive than loblolly bay (Gordonia lasianthus (L.) J. Ellis). X. glabratus entrance hole density and emergence from caged bolts were highest on swampbay and camphortree. In 2010, swampbay was significantly more attractive to X. glabratus than sassafras (Sassafras albidum (Nuttall) Nees), yellow poplar (Liriodendron tulipifera L.), and eastern redbud (Cercis canadensis L.). Sassafras bolts end sealed with a liquid wax-and-water emulsion were more attractive to X. glabratus than end-sealed bolts of yellow poplar and redbud. Relative to unsealed bolts, end seal decreased X. glabratus entrance hole density on swampbay and decreased granulate ambrosia beetle (Xylosandrus crassiusculus (Motschulsky)) trap catch, entrance hole density, and adult emergence from swampbay. X. crassiusculus was not attracted to sassafras, yellow poplar, and redbud and was not more attracted to manuka oil than to unbaited traps. Sassafras was more attractive to X. glabratus than previously reported and supported reproducing populations of the insect. End sealing bolts with a wax-and-water emulsion may not be optimal for attracting and rearing ambrosia beetles in small logs. PMID:22606816

  5. How facial attractiveness affects sustained attention.

    Science.gov (United States)

    Li, Jie; Oksama, Lauri; Hyönä, Jukka

    2016-10-01

    The present study investigated whether and how facial attractiveness affects sustained attention. We adopted a multiple-identity tracking paradigm, using attractive and unattractive faces as stimuli. Participants were required to track moving target faces amid distractor faces and report the final location of each target. In Experiment 1, the attractive and unattractive faces differed in both the low-level properties (i.e., luminance, contrast, and color saturation) and high-level properties (i.e., physical beauty and age). The results showed that the attractiveness of both the target and distractor faces affected the tracking performance: The attractive target faces were tracked better than the unattractive target faces; when the targets and distractors were both unattractive male faces, the tracking performance was poorer than when they were of different attractiveness. In Experiment 2, the low-level properties of the facial images were equalized. The results showed that the attractive target faces were still tracked better than unattractive targets while the effects related to distractor attractiveness ceased to exist. Taken together, the results indicate that during attentional tracking the high-level properties related to the attractiveness of the target faces can be automatically processed, and then they can facilitate the sustained attention on the attractive targets, either with or without the supplement of low-level properties. On the other hand, only low-level properties of the distractor faces can be processed. When the distractors share similar low-level properties with the targets, they can be grouped together, so that it would be more difficult to sustain attention on the individual targets. PMID:27347672

  6. Physical attractiveness and personality development.

    Science.gov (United States)

    Shea, J; Crossman, S M; Adams, G R

    1978-05-01

    A test of the relationship between physical attractiveness and ego development was completed through an interview study of 294 men and women college students. Ss responded to personality measures assessing identity formation, locus of control, and ego functioning and were rated on facial attractiveness and body form scales. Contrary to the physical attractiveness stereotype, attractive and unattractive Ss did not differ in their personality styles. PMID:650605

  7. Perceived Attractiveness and Classroom Interactions

    Science.gov (United States)

    Algozzine, Bob

    1977-01-01

    Adams and Cohen (1974) demonstrated that facial attractiveness was a salient factor in differential student-teacher interactions. This research investigates further the interaction between teachers and children perceived to be attractive or unattractive by those teachers. It was hypothesized that attractive children would exhibit more "positive,"…

  8. Attracting Girls Into Physics

    Science.gov (United States)

    Hosny, Hala M.; Kahil, Heba M.

    2005-10-01

    From our national statistics, it is evident that in the population of physicists there are considerably fewer women than men. Our role is to attract girls to physics and thus decrease this gap. The institutional structure in Egypt provides an equal opportunity for girls to study sciences, including physics. It is reckoned that girls refrain from studying physics due to a group of social and economic factors. We will discuss teaching physics at schools and present some ideas to develop it. The media should play a role in placing female physicists in the spotlight. Unfortunately, careers that require intellectual skills are considered men's careers. This necessitates that society changes the way it sees women and trusts more in their skills and talents. We therefore call for the cooperation of governmental and nongovernmental bodies, together with universities and the production sectors involved. This will ultimately lead to enhancing the entrepreneurial projects related to physics and technology on the one hand, and will encourage girls to find challenging opportunities on the other.

  9. Attracting foreign companies

    International Nuclear Information System (INIS)

    The question of attracting foreign companies to undertake uranium exploration and development is typically a national problem and has to take into account, among other things, political policy, national needs, investment capability and choice, technological level of the country reached and/or planned. These considerations are not specific to uranium exploration; the same questions can be put for growing corn (or rice), producing television sets, or manufacturing space rockets. The answers are necessarily different for each country. However, mineral exploration (including uranium) presents important differences that are related to the special investment risks associated with these activities. The investor in mining development can never be sure of earning his money back. This will not be the case in other industries as long as the business is operated in an adequate way. Under these conditions it is very difficult to provide precise guide lines. The host country must pay close attention to the risk involved when making incentive regulations. The best way is for the government to understand very well the foreign investor's motivations and to accommodate, as well as possible within national policies, respect for the interests of both parties

  10. The Role of Attractiveness and Aggression in High School Popularity

    Science.gov (United States)

    Borch, Casey; Hyde, Allen; Cillessen, Antonius H. N.

    2011-01-01

    This study examines the effects of physical attractiveness and aggression on popularity among high school students. Previous work has found positive relationships between aggression and popularity and physical attractiveness and popularity. The current study goes beyond this work by examining the interactive effects of physical attractiveness and…

  11. Colony-level impacts of parasitoid flies on fire ants.

    OpenAIRE

    Mehdiabadi, Natasha J; Gilbert, Lawrence E

    2002-01-01

    The red imported fire ant is becoming a global ecological problem, having invaded the United States, Puerto Rico, New Zealand and, most recently, Australia. In its established areas, this pest is devastating natural biodiversity. Early attempts to halt fire ant expansion with pesticides actually enhanced its spread. Phorid fly parasitoids from South America have now been introduced into the United States as potential biological control agents of the red imported fire ant, but the impact of th...

  12. HYMENOPTERAN PARASITOIDS: LABORATORY REARING AND EVALUATION OF STORAGE TECHNIQUES

    OpenAIRE

    Binazzi, Francesco

    2014-01-01

    The present work focused on O. pityocampae (Mercet) (Hymenoptera Encyrtidae), an indigenous and polyphagous egg-parasitoid that might play a role in biological control programs against Thaumetopoea pityocampa (Den. & Shiff.) (Lepidoptera Notodontidae). Therefore biological parameters of this encyrtid reared on alternative host eggs were analyzed by testing its behavior and reproductive parameters. Time between oviposition and progeny emergence, sex ratio of offspring, parasitization rate and ...

  13. Mountain aphid and parasitoid guilds on Aconitum spp. in Europe

    Czech Academy of Sciences Publication Activity Database

    Havelka, Jan; Tomanović, Ž.; Kos, K.; Kavallieratos, N. G.; Janeček, J.; Pons, X.; Rakhshani, E.; Starý, Petr

    2014-01-01

    Roč. 67, č. 1 (2014), s. 57-61. ISSN 1721-8861 Grant ostatní: Ministry of Education, Science and Technological Development(RS) III43001 Institutional support: RVO:60077344 Keywords : aphis * Aphididae * parasitoids Subject RIV: EH - Ecology, Behaviour Impact factor: 1.494, year: 2014 http://www.bulletinofinsectology.org/pdfarticles/vol67-2014-057-061havelka.pdf

  14. Genomic and karyotypic variation in Drosophila parasitoids (Hymenoptera, Cynipoidea, Figitidae

    Directory of Open Access Journals (Sweden)

    Vladimir Gokhman

    2011-08-01

    Full Text Available Drosophila melanogaster Meigen, 1830 has served as a model insect for over a century. Sequencing of the 11 additional Drosophila Fallen, 1823 species marks substantial progress in comparative genomics of this genus. By comparison, practically nothing is known about the genome size or genome sequences of parasitic wasps of Drosophila. Here, we present the first comparative analysis of genome size and karyotype structures of Drosophila parasitoids of the Leptopilina Förster, 1869 and Ganaspis Förster, 1869 species. The gametic genome size of Ganaspis xanthopoda (Ashmead, 1896 is larger than those of the three Leptopilina species studied. The genome sizes of all parasitic wasps studied here are also larger than those known for all Drosophila species. Surprisingly, genome sizes of these Drosophila parasitoids exceed the average value known for all previously studied Hymenoptera. The haploid chromosome number of both Leptopilina heterotoma (Thomson, 1862 and L. victoriae Nordlander, 1980 is ten. A chromosomal fusion appears to have produced a distinct karyotype for L. boulardi (Barbotin, Carton et Keiner-Pillault, 1979 (n = 9, whose genome size is smaller than that of wasps of the L. heterotoma clade. Like L. boulardi, the haploid chromosome number for G. xanthopoda is also nine. Our studies reveal a positive, but non linear, correlation between the genome size and total chromosome length in Drosophila parasitoids. These Drosophila parasitoids differ widely in their host range, and utilize different infection strategies to overcome host defense. Their comparative genomics, in relation to their exceptionally well-characterized hosts, will prove to be valuable for understanding the molecular basis of the host-parasite arms race and how such mechanisms shape the genetic structures of insect communities.

  15. The effects of waist-to-hip ratio and body weight on male judgements of female physical attractiveness, wife desirability, and health, both within and between cultures.

    OpenAIRE

    McLean, Julia

    2007-01-01

    Evolutionary theories maintain that female physical attractiveness has evolved to honestly signal health and reproductive potential. Both a low waist-to-hip ratio (WHR) and a critical range of body weight have received considerable attention in this respect. As a result these cues should be universally utilised by males when evaluating female attractiveness. However, a lack of cross-cultural uniformity in these male judgements has led some researchers to reject this theory and ...

  16. Evaluation of the attractive effect of coloured sticky traps for Aleurocanthus spiniferus (Quaintance and its monitoring method in tea garden in China

    Directory of Open Access Journals (Sweden)

    Y. Wang

    2015-12-01

    Full Text Available Aleurocanthus spiniferus (Quaintance, namely tea spiny whitefly (TSW, belongs to the family Aleyrodidae in the order Homoptera, widespread in tea trees and fruit trees in many countries or regions. In this study, the preference of TSW for different colours was evaluated in tea gardens. Yellow was the colour most preferred by TSW, followed by pink, red, white and other colours. The controlling technologies about the number of sticky traps in a certain area of tea garden and the height of sticky traps above tea canopy were also evaluated, the results indicated that the attractive effect of 20 traps/667 m2 of trials area and the height of 10 cm above tea canopy were significantly higher than others treatments. In addition, more TSW was caught at 11:00-15:00, followed by 7:00-11:00, and 15:00-19:00 in a daytime; higher activity level of male adults was at 7:00-11:00 and 11:00-15:00 in day time (95.13% and 94.97% of caught TSW, indicating a higher activity level for male adult.

  17. The effect of the attractive well of the potential energy surface for Ne-HCl on rotationally inelastic partial wave cross sections

    Institute of Scientific and Technical Information of China (English)

    Yu Chun-Ri; Shi Shou-Hua; Wang Rong-Kai; Yang Xiang-Dong

    2007-01-01

    An interaction potential of the Ne-HCl van der Waals complex is obtained by utilizing the Huxley analytic potential function to fit the accurate interaction energy data, which have been computed at the coupled cluster singles and doubles including connected triple excitations level and with the augmented correlation consistent polarized valence quintuple zeta basis set extended with a set of 3s3p2d1f1g mid-bond functions [CCSD (T)/aug-cc-pV5Z-33211]. The close coupling calculation of state-to-state partial cross sections for collision of Ne with HCl is first performed by employing the fitted interaction potential. This calculation is performed at the incident energies: 40, 60, 75 and 100 meV, separately. The effects of the long-range attractive and the short-range anisotropic interactions on the inelastic state-to-state partial cross sections are discussed in detail. Two maxima are present in the rotationally inelastic partial cross sections and they originate from different mechanisms.

  18. Toxicity of organic supplies for the egg parasitoid Telenomus podisi

    Directory of Open Access Journals (Sweden)

    Débora Mello da Silva

    2014-01-01

    Full Text Available Toxicity (dosage per hectare of: 1 Baculovirus anticarsia 140x109 cpi; 2 Bacillus thuringiensis 16.8g; 3 Azadirachtin-A, azadirachtin-B, nimbina and salamina 9.6 ppm; 4 Rotenoids 4 liters; 5 Nitrogen 1.3%, phosphorus 3.0% and total organic carbon 8.0% 3 liters; 6 Sodium silicate 2% 4 liters; 7 Copper 7% + calcium 3.3% 1.8 liters; 8 Sulfur 20% + quicklime 10% 1.8 liters; 9 Chlorpyrifos 384g; 10 Distilled H2O (control were evaluated for pupae and adults of Telenomus podisi. Treatments from 1 to 8 were in general harmless (class 1 to both pupae and adults of T. podisi. Among them, only treatment 5 and 7 presented slightly toxic to the parasitoid with a reduction in parasitism 5 days after F1 parasitoid emergence. Differently, the chlorpyrifos was classified as slightly harmful (class 2 or moderately harmful (class 3. Therefore, the use of the tested organic agricultural supplies in the production of organic soybean is viable, without impairing the natural biological control allowed by this egg parasitoid. Chlorpyrifos use, on the other hand, is not allowed in organic soybean, but even on convention crop production, could whenever possible, be replaced by other products more compatible with T. podisi preservation.

  19. A hitch-hiker’s guide to parasitism: the chemical ecology of phoretic insect parasitoids

    NARCIS (Netherlands)

    Huigens, M.E.; Fatouros, N.E.

    2013-01-01

    Phoretic arthropods use other animals as vehicles to migrate to new environments. Among insect parasitoids, phoresy is almost exclusively restricted to minute wasp species that develop in or on the smallest and most inconspicuous life stage of their host: the egg. Females of about 35 egg parasitoid

  20. Diversity of Species and Behavior of Hymenopteran Parasitoids of Ants: A Review

    Directory of Open Access Journals (Sweden)

    Jean-Paul Lachaud

    2012-01-01

    Full Text Available Reports of hymenopterans associated with ants involve more than 500 species, but only a fraction unambiguously pertain to actual parasitoids. In this paper, we attempt to provide an overview of both the diversity of these parasitoid wasps and the diversity of the types of interactions they have formed with their ant hosts. The reliable list of parasitoid wasps using ants as primary hosts includes at least 138 species, reported between 1852 and 2011, distributed among 9 families from 3 superfamilies. These parasitoids exhibit a wide array of biologies and developmental strategies: ecto- or endoparasitism, solitary or gregarious, and idio- or koinobiosis. All castes of ants and all developmental stages, excepting eggs, are possible targets. Some species parasitize adult worker ants while foraging or performing other activities outside the nest; however, in most cases, parasitoids attack ant larvae either inside or outside their nests. Based on their abundance and success in attacking ants, some parasitoid wasps like diapriids and eucharitids seem excellent potential models to explore how parasitoids impact ant colony demography, population biology, and ant community structure. Despite a significant increase in our knowledge of hymenopteran parasitoids of ants, most of them remain to be discovered.

  1. Egg distributions and the information a solitary parasitoid has and uses for its oviposition decisions

    NARCIS (Netherlands)

    Hemerik, L.; Hoeven, van der N.; Alphen, van J.J.M.

    2002-01-01

    Approximately three decades ago the question was first answered “whether parasitoids are able to assess the number or origin of eggs in a host” for a solitary parasitoid, Leptopilina heterotoma, by fitting theoretically derived distributions to empirical ones. We extend the set of different theoreti

  2. Contrasting Patterns of Host Adaptation in Two Egg Parasitoids of the Pine Processionary Moth (Lepidoptera: Thaumetopoeidae).

    Science.gov (United States)

    Ruschioni, Sara; Riolo, Paola; Isidoro, Nunzio; Romani, Roberto; Petrucco-Toffolo, Edoardo; Zovi, Daniel; Battisti, Andrea

    2015-06-01

    Adaptation of parasitoids to their phytophagous host is often mediated by environmental conditions and by the food plant of the phytophagous host. Therefore, the host food plant can indirectly affect the survival and fitness of parasitoids that also attack quiescent host stages, such as eggs, in which the resources available to the immature parasitoid stages are limited. Our aim was to investigate how two egg parasitoid species of the pine processionary moth, Thaumetopoea pityocampa (Denis & Schiffermüller), respond to variations in egg traits at the extremes of a west-to-east geographic gradient in northern Italy. We considered one specialist [Baryscapus servadeii (Domenichini)] and one generalist [Ooencyrtus pityocampae (Mercet)] parasitoid, which reproduce mainly by thelytokous parthenogenesis and are common throughout the whole range of this pest. The size and shell structure of the pine processionary moth eggs were studied under light microscopy and tested experimentally under controlled conditions. We can conclude that 1) the pine processionary moth egg shell thickness is inversely proportional to the parasitism performance; 2) the larger eggs from the pine processionary moth eastern population produce parasitoid females of a larger size, which have greater realized fecundity; 3) the generalist parasitoid performs successfully with either the "home" or "away" (i.e., from both extremes of the geographic gradient) pine processionary moth eggs, which is not the case for the specialist parasitoid. The implications of these responses in the regulation of phytophagous populations are numerous and should be considered in population dynamics studies and pest management programs. PMID:26313953

  3. Mortality of Plutella xylostella (Lepidoptera, Plutellidae by parasitoids in the Province of Santa Fe, Argentina

    Directory of Open Access Journals (Sweden)

    Isabel Bertolaccini

    2011-09-01

    Full Text Available Mortality of Plutella xylostella (Lepidoptera, Plutellidae by parasitoids in the Province of Santa Fe, Argentina. Plutella xylostella (Linnaeus, 1758 (Lepidoptera, Plutellidae larvae cause severe economic damage on cabbage, Brassica oleracea L. variety capitata (Brassicaceae, in the horticultural fields in the Province of Santa Fe, Argentina. Overuse of broad spectrum insecticides affects the action of natural enemies of this insect on cabbage. The objectives of this work were to identify the parasitoids of P. xylostella and to determine their influence on larva and pupa mortality. Weekly collections of larvae and pupae were randomly conducted in cabbage crops during spring 2006 and 2007. The immature forms collected were classified according to their developmental stage: L1 and L2 (Ls = small larvae, L3 (Lm = medium larvae, L4 (Ll = large larvae, pre-pupae and pupae (P. Each individual was observed daily in the laboratory until the adult pest or parasitoid emergence. We identified parasitoids, the number of instar and the percentage of mortality of P. xylostella for each species of parasitoid. Parasitoids recorded were: Diadegma insulare (Cresson, 1875 (Hymenoptera, Ichneumonidae, Oomyzus sokolowskii (Kurdjumov, 1912 (Hymenoptera, Eulophidae, Cotesia plutellae (Kurdjumov, 1912 (Hymenoptera, Braconidae and an unidentified species of Chalcididae (Hymenoptera. Besides parasitoids, an unidentified entomopathogenic fungus was also recorded in 2006 and 2007. In 2006, the most successful parasitoids were D. insulare and O. sokolowskii, while in 2007 only D. insulare exerted a satisfactory control and it attacked the early instars of the pest.

  4. Parasitoids and predators of armored scales in some orchards in Serbia

    OpenAIRE

    Draga Graora; Radoslava Spasić; Anđa Vučetić

    2009-01-01

    Five parasitoid and five predator species were registered on four armored scale species in apple, pear, peach and plum orchards at 16 sites in Serbia. The armored scales found were: Diaspidiotus perniciosus (Comstock), Pseudaulacaspis pentagona (Targioni-Tozzetti), Epidiaspis leperii (Signoret) and Lepidosaphes ulmi (L.). The parasitoid species detected were: Encarsia (=Prospaltella) perniciosi (Tow.), Encarsia (=Prospaltella) berlesei (How.), Aphytis proclia (Wal.), Aphytis mytilaspidis (Le ...

  5. Understanding talent attraction: The influence of financial rewards elements on perceived job attractiveness

    Directory of Open Access Journals (Sweden)

    Anton Schlechter

    2014-02-01

    Full Text Available Orientation: In order to attract knowledge workers and maintain a competitive advantage,it is necessary for organisations to understand how knowledge workers are attracted todifferent types and levels of financial rewards.Research purpose: This research investigated a set of financial reward elements (remuneration, employee benefits and variable pay to determine whether knowledgeworkers perceived them as attractive inducements when considering a job or position.Motivation for the study: In South Africa there is a shortage of talent, largely due to highrates of emigration of scarce skills (human capital. Financial rewards or inducementsare necessary to attract talent and it is essential to assess which of these rewards are mostsuccessful in this regard.Method: A 23 full-factorial experimental design (field experiment was used. The threefinancial reward elements (remuneration, employee benefits and variable pay weremanipulated in a fictitious job advertisement (each at two levels. Eight (2 × 2 × 2 = 8 differentversions of a job advertisement were used as a stimulus to determine the effect of financialreward elements on perceived job attractiveness. A questionnaire was used to measure howparticipants perceived the attractiveness of the job. A convenience sampling approach wasused. Different organisations throughout South Africa, as well as corporate members of the South African Reward Association, were asked to participate in the study. Respondents (n = 169 were randomly assigned to the various experimental conditions (i.e. one of the eightadvertisements. Data were analysed using descriptive statistics. A full-factorial analysis ofvariance was used to investigate if significant main effects could be found.Main findings: Participants considered high levels of remuneration, the inclusion ofbenefits and variable pay to be significant job attraction factors within a reward package. Remuneration was found to have the largest main effect on job

  6. Measuring tax attractiveness across countries

    OpenAIRE

    Keller, Sara; Schanz, Deborah

    2013-01-01

    This paper develops a new tax measure - the Tax Attractiveness Index - reflecting the attractiveness of a country's tax environment and the tax planning opportunities that are offered. Specifically, the Tax Attractiveness Index covers 16 different components of real-world tax systems, such as the statutory tax rate, the taxation of dividends and capital gains, withholding taxes, the existence of a group taxation regime, loss offset provision, the double tax treaty network, thin capitalization...

  7. Habitat selection of a parasitoid mediated by volatiles informing on host and intraguild predator densities

    DEFF Research Database (Denmark)

    Cotes, Belén; Rännbäck, Linda Marie; Björkman, Maria; Norli, Hans Ragnar; Meyling, Nicolai Vitt; Rämert, Birgitta; Anderson, Peter

    2015-01-01

    To locate and evaluate host patches before oviposition, parasitoids of herbivorous insects utilize plant volatiles and host-derived cues, but also evaluate predator-derived infochemicals to reduce predation risks. When foraging in host habitats infested with entomopathogenic fungi that can infect...... both a parasitoid and its host, parasitoids may reduce the risk of intraguild predation (IGP) by avoiding such patches. In this study, we examined whether the presence of the entomopathogenic fungi Metarhizium brunneum and Beauveria bassiana in soil habitats of a root herbivore, Delia radicum, affects...... the behavior of Trybliographa rapae, a parasitoid of D. radicum. Olfactometer bioassays revealed that T. rapae avoided fungal infested host habitats and that this was dependent on fungal species and density. In particular, the parasitoid avoided habitats with high densities of the more virulent fungus...

  8. Rearing parasitoids of spruce budworm from northern Alberta. Forest management note No. 61

    Energy Technology Data Exchange (ETDEWEB)

    Williams, D.J.

    1994-12-31

    Numerous species of parasitic flies and wasps attack spruce budworm (SBW) throughout its geographic range and at all immature stages, but little is known about these dynamics in northern Alberta. This note gives the results of a study on rearing parasitoids from northern Alberta. Parasitoids sampled lay eggs on SBW larvae, live as larvae in the host body, and emerge from older larvae or pupae. Sampling techniques therefore include examination of the incidence of egg laying, the presence of parasitoid larvae in the host, and the emergence of adult parasitoids. In this study, large numbers of SBW larvae were individually reared to obtain adult parasitoids, but extensive dissection of SBW larvae was avoided, and results were obtained using limited time and materials.

  9. Physical Attractiveness Stereotypes about Marriage: Attractiveness Matching Is Good.

    Science.gov (United States)

    Sussman, Steve; And Others

    Previous research on physical attractiveness stereotypes about marriage have used stimulus individuals in isolation. To examine these attractiveness stereotypes using couples as targets, 72 college students (36 females, 36 males) rated eight photographs of four male-female couple types. Members of each couple were either matched (attractive…

  10. Host size and spatiotemporal patterns mediate the coexistence of specialist parasitoids.

    Science.gov (United States)

    Pekas, Apostolos; Tena, Alejandro; Harvey, Jeffrey A; Garcia-Mari, Ferran; Frago, Enric

    2016-05-01

    Many insect parasitoids are highly specialized and thus develop on only one or a few related host species, yet some hosts are attacked by many different parasitoid species in nature. For this reason, they have been often used to examine the consequences of competitive interactions. Hosts represent limited resources for larval parasitoid development and thus one competitor usually excludes all others. Although parasitoid competition has been debated and studied over the past several decades, understanding the factors that allow for coexistence among species sharing the same host in the field remains elusive. Parasitoids may be able to coexist on the same host species if they partition host resources according to size, age, or stage, or if their dynamics vary at spatial and temporal scales. One area that has thus far received little experimental attention is if competition can alter host usage strategies in parasitoids that in the absence of competitors attack hosts of the same size in the field. Here, we test this hypothesis with two parasitoid species in the genus Aphytis, both of which are specialized on the citrus pest California red scale Aonidiella aurantii. These parasitoids prefer large scales as hosts and yet coexist in sympatry in eastern parts of Spain. Parasitoids and hosts were sampled in 12 replicated orange groves. When host exploitation by the stronger competitor, A. melinus, was high the poorer competitor, A. chrysomphali, changed its foraging strategy to prefer alternative plant substrates where it parasitized hosts of smaller size. Consequently, the inferior parasitoid species shifted both its habitat and host size as a result of competition. Our results suggest that density-dependent size-mediated asymmetric competition is the likely mechanism allowing for the coexistence of these two species, and that the use of suboptimal (small) hosts can be advantageous under conditions imposed by competition where survival in higher quality larger hosts may

  11. Lack of phenotypic and evolutionary cross-resistance against parasitoids and pathogens in Drosophila melanogaster.

    Directory of Open Access Journals (Sweden)

    Alex R Kraaijeveld

    Full Text Available BACKGROUND: When organisms are attacked by multiple natural enemies, the evolution of a resistance mechanism to one natural enemy will be influenced by the degree of cross-resistance to another natural enemy. Cross-resistance can be positive, when a resistance mechanism against one natural enemy also offers resistance to another; or negative, in the form of a trade-off, when an increase in resistance against one natural enemy results in a decrease in resistance against another. Using Drosophila melanogaster, an important model system for the evolution of invertebrate immunity, we test for the existence of cross-resistance against parasites and pathogens, at both a phenotypic and evolutionary level. METHODS: We used a field strain of D. melanogaster to test whether surviving parasitism by the parasitoid Asobara tabida has an effect on the resistance against Beauveria bassiana, an entomopathogenic fungus; and whether infection with the microsporidian Tubulinosema kingi has an effect on the resistance against A. tabida. We used lines selected for increased resistance to A. tabida to test whether increased parasitoid resistance has an effect on resistance against B. bassiana and T. kingi. We used lines selected for increased tolerance against B. bassiana to test whether increased fungal resistance has an effect on resistance against A. tabida. RESULTS/CONCLUSIONS: We found no positive cross-resistance or trade-offs in the resistance to parasites and pathogens. This is an important finding, given the use of D. melanogaster as a model system for the evolution of invertebrate immunity. The lack of any cross-resistance to parasites and pathogens, at both the phenotypic and the evolutionary level, suggests that evolution of resistance against one class of natural enemies is largely independent of evolution of resistance against the other.

  12. Esthetic effect of the buccal corridor size and amount of tooth-gingival display on smile attractiveness in two student population

    Directory of Open Access Journals (Sweden)

    Hooman Zarif Najafi

    2015-05-01

    Full Text Available 3- Dentist   Background and Aims: An attractive, well-balanced smile is a paramount treatment objective of the modern orthodontic therapy. The purpose of this study was to determine the effects of the buccal corridor size and tooth-gingival display on the smile esthetics as perceived by two groups of the students.   Materials and Methods: A colored image of a woman frontal posed smile was selected. The image was altered digitally to produce different buccal corridor sizes (6%, 12.5% and 20% and different tooth-gingival displays (maxillary central incisors and 2 mm of gingival, maxillary central incisors and dental papilla and 80% of the maxillary central incisors. The different buccal corridor sizes and tooth-gingival displays were combined to produce 9 images. These altered images were rated by 120 medical and dental students using Visual Analogue Scale (VAS. Data were analyzed using Mann-Whitney test, Pairwise comparison LSD test, Repeated measure MANOVA and ICC (Intraclass Correlation Coefficient.   Results: The smile which had the buccal corridor size of 12.5% and complete incisor display without gingival display received the highest rates among the nine smile images in the dental students group. But in the medical students group the smile with the buccal corridor size of 12.5% and 2 mm gingival display, received the highest rates among the nine smile images. There was no significant difference in judging between the male and female raters for the both groups (P>0.05. The dental students were more critical about the increasing of the gingival display.   Conclusion: In the treatment procedure that may lead to the combination of wide buccal corridor and more tooth-gingival show, more caution should be considered.

  13. Estimating geocenter motion and barystatic sea-level variability from GRACE observations with explicit consideration of self-attraction and loading effects

    Science.gov (United States)

    Bergmann-Wolf, Inga; Dobslaw, Henryk

    2016-04-01

    Estimating global barystatic sea-level variations from monthly mean gravity fields delivered by the Gravity Recovery and Climate Experiment (GRACE) satellite mission requires additional information about geocenter motion. These variations are not available directly due to the mission implementation in the CM-frame and are represented by the degree-1 terms of the spherical harmonics expansion. Global degree-1 estimates can be determined with the method of Swenson et al. (2008) from ocean mass variability, the geometry of the global land-sea distribution, and GRACE data of higher degrees and orders. Consequently, a recursive relation between the derivation of ocean mass variations from GRACE data and the introduction of geocenter motion into GRACE data exists. In this contribution, we will present a recent improvement to the processing strategy described in Bergmann-Wolf et al. (2014) by introducing a non-homogeneous distribution of global ocean mass variations in the geocenter motion determination strategy, which is due to the effects of loading and self-attraction induced by mass redistributions at the surface. A comparison of different GRACE-based oceanographic products (barystatic signal for both the global oceans and individual basins; barotropic transport variations of major ocean currents) with degree-1 terms estimated with a homogeneous and non-homogeneous ocean mass representation will be discussed, and differences in noise levels in most recent GRACE solutions from GFZ (RL05a), CSR, and JPL (both RL05) and their consequences for the application of this method will be discussed. Swenson, S., D. Chambers and J. Wahr (2008), Estimating geocenter variations from a combination of GRACE and ocean model output, J. Geophys. Res., 113, B08410 Bergmann-Wolf, I., L. Zhang and H. Dobslaw (2014), Global Eustatic Sea-Level Variations for the Approximation of Geocenter Motion from GRACE, J. Geod. Sci., 4, 37-48

  14. Acute and population level toxicity of imidacloprid and fenpyroximate on an important egg parasitoid, Trichogramma cacoeciae (Hymenoptera: Trichogrammatidae).

    Science.gov (United States)

    Saber, Moosa

    2011-08-01

    One focus of integrated pest management (IPM) is the use of biological and chemical control in an optimal way. The availability of selective pesticides is important as is information about both lethal and sublethal effects of pesticides on biocontrol agents. Acute and sublethal effects of imidacloprid and fenpyroximate exposure were studied on adult stage of egg parasitoid Trichogramma cacoeciae Marchal and the emergence rate and life table parameters were determined. The adult wasps were exposed to field recommended concentration (FRC) of the pesticides on glass plates. Field rates of imidacloprid and fenpyroximate caused 100 and 32% adult mortality, respectively. Based on concentration-response experiments, the LC(50) values of imidacloprid and fenpyroximate were 6.25 and 1,949 ppm, respectively. The effect of imidacloprid and fenpyroximate on larvae, prepupae and pupae of the parasitoid was tested by exposing parasitized eggs of Sitotroga cerealella Olivier or Cydia pomonella L. to the FRC. Imidacloprid and fenpyroximate reduced adult emergence by 10.7 and 29%, respectively, when S. cerealella eggs were used as the host and 10.9 and 24.9%, respectively, when C. pomonella eggs were used as the host. Population parameters of emerged adults from treated pre-imaginal stages by FRC of the pesticides were also studied. The parameters were longevity and progeny production of emergent adults and also intrinsic rate of increase (r ( m )), generation time (T) and doubling time (DT). Longevity and progeny production of the emergent adults was not affected by pesticide exposure in comparison to the control. In addition, none of population parameters such as r ( m ), T and DT were affected by pesticide exposure. The intrinsic rate of increase for the control, fenpyroximate and imidacloprid exposed populations were 0.388, 0.374, and 0.372 female offspring per female per day, respectively. Overall, results of this study suggest a relative compatibility between fenpyroximate

  15. Ordinal Position, Approval Motivation, and Interpersonal Attraction

    Science.gov (United States)

    Nowicki, Stephen, Jr.

    1971-01-01

    Results of the study suggest that birth-order effects might be included within the wider framework of approval-dependency theory. Females tend to account for a significant share of birth-order effects. More particularly, firstborn females accounted for much of the differences in expressed attraction as well as need for social approval. (Author)

  16. Physical Attractiveness and Courtship Progress.

    Science.gov (United States)

    White, Gregory L.

    1980-01-01

    Among college students who were casual or serious daters, greater relative attractiveness was positively correlated with greater relative availability of opposite-sexed friends and negatively correlated with worrying about partner's potential involvement with others. A 9-month follow-up revealed that similarity of attractiveness was predictive of…

  17. Physical Attractiveness and Interpersonal Influence

    Science.gov (United States)

    Dion, Karen K.; Stein, Steven

    1978-01-01

    Examines the hypothesis that attractive individuals should be more successful with opposite-sex peers but less successful with same-sex peers than unattractive individuals. Also investigates the influence strategies employed by persons differing in attractiveness since nothing is currently known about the actual behavior exhibited by attractive…

  18. Apparent Acquired Resistance by a Weevil to Its Parasitoid Is Influenced by Host Plant.

    Science.gov (United States)

    Goldson, Stephen L; Tomasetto, Federico

    2016-01-01

    Field parasitism rates of the Argentine stem weevil Listronotus bonariensis (Kuschel; Coleoptera: Curculionidae) by Microctonus hyperodae Loan (Hymenoptera: Braconidae) are known to vary according to different host Lolium species that also differ in ploidy. To further investigate this, a laboratory study was conducted to examine parasitism rates on tetraploid Italian Lolium multiflorum, diploid Lolium perenne and diploid hybrid L. perenne ×L. multiflorum; none of which were infected by Epichloë endophyte. At the same time, the opportunity was taken to compare the results of this study with observations made during extensive laboratory-based research and parasitoid-rearing in the 1990s using the same host plant species. This made it possible to determine whether there has been any change in weevil susceptibility to the parasitoid over a 20 year period when in the presence of the tetraploid Italian, diploid perennial and hybrid host grasses that were commonly in use in the 1990's. The incidence of parasitism in cages, in the presence of these three grasses mirrored what has recently been observed in the field. When caged, weevil parasitism rates in the presence of a tetraploid Italian ryegrass host were significantly higher (75%) than rates that occurred in the presence of either the diploid perennial (46%) or the diploid hybrid (52%) grass, which were not significantly different from each other. This is very different to laboratory parasitism rates in the 1990s when in the presence of both of the latter grasses high rates of parasitism (c. 75%) were recorded. These high rates are typical of those still found in weevils in the presence of both field and caged tetraploid Italian grasses. In contrast, the abrupt decline in weevil parasitism rates points to the possibility of evolved resistance by the weevil to the parasitoid in the diploid and hybrid grasses, but not so in the tetraploid. The orientation of plants in the laboratory cages had no significant effect on

  19. Physical attractiveness stereotype and memory.

    Science.gov (United States)

    Rohner, Jean-Christophe; Rasmussen, Anders

    2011-08-01

    Three experiments examined explicit and implicit memory for information that is congruent with the physical attractiveness stereotype (i.e. attractive-positive and unattractive-negative) and information that is incongruent with the physical attractiveness stereotype (i.e. attractive-negative and unattractive-positive). Measures of explicit recognition sensitivity and implicit discriminability revealed a memorial advantage for congruent compared to incongruent information, as evident from hit and false alarm rates and reaction times, respectively. Measures of explicit memory showed a recognition bias toward congruent compared to incongruent information, where participants tended to call congruent information old, independently of whether the information had been shown previously or not. This recognition bias was unrelated to reports of subjective confidence in retrieval. The present findings shed light on the cognitive mechanisms that might mediate discriminatory behavior towards physically attractive and physically unattractive individuals. PMID:21255024

  20. The Red-Attractiveness Effect, Applying the Ioannidis and Trikalinos (2007b) Test, and the Broader Scientific Context: A Reply to Francis (2013)

    Science.gov (United States)

    Elliot, Andrew J.; Maier, Markus A.

    2013-01-01

    Francis (2013) tested for and found evidence of publication bias in 1 of the 3 focal relations examined in Elliot et al. (2010), that between red and attractiveness. He then called into question the research as a whole and the field of experimental psychology more generally. Our reply has 3 foci. First, we attend to the bottom line regarding the…