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Sample records for attract parasitoids effects

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

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    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.

  2. Are synthetic pheromone captures predictive of parasitoid densities as a kairomonal attracted tool?

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    Mohamed Hassan Bayoumy

    2011-04-01

    Full Text Available Abundance of White Peach scale (WPS, Pseudaulacaspis pentagona (Targioni-Tozzetti and San José scale (SJS, Diaspidiotus perniciosus (Comstock (Hemiptera: Diaspididae adult males and their attracted parasitoids were monitored using pheromone and sticky tape traps in an orchard of Budapest, Hungary, during 2010. In this study, we tried answer on the question raised whether synthetic commercial pheromones of WSP or SJS could work as a kairomonal stimulant and positively attract higher numbers of the specialized parasitoids. Although pheromone traps attracted a wide range of parasitoid species, most of them were accidentally. However, the parasitoid Thomsonisca amathus (Walker (Hymenoptera: E ncyrtidae and the parasitoid Encarsia perniciosi (Tower (Hymenoptera: Aphelinidae significantly respond to the sex pheromones of WPS and SJS, respectively, suggesting that they may play an important role in host location.

  3. Assessing the suitability of flowering herbs as parasitoid food sources: flower attractiveness and nectar accessibility

    NARCIS (Netherlands)

    Wäckers, F.L.

    2004-01-01

    Eleven insect-pollinated plant species were investigated with respect to their olfactory attractiveness and nectar accessibility for the parasitoid species Cotesia glomerata (Hymenoptera: Braconidae), Heterospilus prosopidis (Hymenoptera: Braconidae), and Pimpla turionellae (Hymenoptera:

  4. Egg parasitoid attraction toward induced plant volatiles is disrupted by a non-host herbivore attacking above or belowground plant organs.

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    Rihem eMoujahed

    2014-11-01

    Full Text Available Plants respond to insect oviposition by emission of oviposition-induced plant volatiles (OIPVs which can recruit egg parasitoids of the attacking herbivore. To date, studies demonstrating egg parasitoid attraction to OIPVs have been carried out in tritrophic systems consisting of one species each of plant, herbivore host, and the associated egg parasitoid. Less attention has been given to plants experiencing multiple attacks by host and non-host herbivores that potentially could interfere with the recruitment of egg parasitoids as a result of modifications to the OIPV blend. Egg parasitoid attraction could also be influenced by the temporal dynamics of multiple infestations, when the same non-host herbivore damages different organs of the same plant species. In this scenario we investigated the responses of egg parasitoids to feeding and oviposition damage using a model system consisting of Vicia faba, the above-ground insect herbivore Nezara viridula, the above- and below-ground insect herbivore Sitona lineatus, and Trissolcus basalis, a natural enemy of N. viridula. We demonstrated that the non-host S. lineatus disrupts wasp attraction toward plant volatiles induced by the host N. viridula. Interestingly, V. faba damage inflicted by either adults (i.e. leaf-feeding or larvae (i.e. root-feeding of S. lineatus, had a similar disruptive effect on T. basalis host location, suggesting that a common interference mechanism might be involved. Neither naïve wasps or wasps with previous oviposition experience were attracted to plant volatiles induced by N. viridula when V. faba plants were concurrently infested with S. lineatus adults or larvae. Analysis of the volatile blends among healthy plants and above-ground treatments show significant differences in terms of whole volatile emissions. Our results demonstrate that induced plant responses caused by a non-host herbivore can disrupt the attraction of an egg parasitoid to a plant that is also infested

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

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    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.

  6. Silicon Supplementation Alters the Composition of Herbivore Induced Plant Volatiles and Enhances Attraction of Parasitoids to Infested Rice Plants

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    Jian Liu

    2017-07-01

    Full Text Available Silicon (Si is important in plant defenses that operate in a direct manner against herbivores, and work in rice (Oryza sativa has established that this is mediated by the jasmonate signaling pathway. Plant defenses also operate indirectly, by the production of herbivore induced plant volatiles (HIPVs that attract predators and parasitoids of herbivores. These indirect defenses too are mediated by the jasmonate pathway but no earlier work has demonstrated an effect of Si on HIPVs. In this study, we tested the effect of Si supplementation versus Si deprivation to rice plants on subsequent HIPV production following feeding by the important pest, rice leaffolder (Cnaphalocrocis medinalis. Gas chromatography–mass spectrometry analyses showed lower production of α-bergamotene, β-sesquiohellandrene, hexanal 2-ethyl, and cedrol from +Si herbivore-infested plants compared with -Si infested plants. These changes in plant chemistry were ecologically significant in altering the extent to which parasitoids were attracted to infested plants. Adult females of Trathala flavo-orbitalis and Microplitis mediator both exhibited greater attraction to the HIPV blend of +Si plants infested with their respective insect hosts compared to -Si infested plants. In equivalent studies using RNAi rice plants in which jasmonate perception was silenced there was no equivalent change to the HIPV blend associated with Si treatment; indicating that the effects of Si on HIPVs are modulated by the jasmonate pathway. Further, this work demonstrates that silicon alters the HIPV blend of herbivore-infested rice plants. The significance of this finding is that there are no earlier-published studies of this phenomenon in rice or any other plant species. Si treatment to crops offers scope for enhancing induced, indirect defenses and associated biological control of pests because parasitoids are more strongly attracted by the HIPVs produced by +Si plants.

  7. Silicon Supplementation Alters the Composition of Herbivore Induced Plant Volatiles and Enhances Attraction of Parasitoids to Infested Rice Plants.

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    Liu, Jian; Zhu, Jiwei; Zhang, Pengjun; Han, Liwei; Reynolds, Olivia L; Zeng, Rensen; Wu, Jinhong; Shao, Yue; You, Minsheng; Gurr, Geoff M

    2017-01-01

    Silicon (Si) is important in plant defenses that operate in a direct manner against herbivores, and work in rice (Oryza sativa) has established that this is mediated by the jasmonate signaling pathway. Plant defenses also operate indirectly, by the production of herbivore induced plant volatiles (HIPVs) that attract predators and parasitoids of herbivores. These indirect defenses too are mediated by the jasmonate pathway but no earlier work has demonstrated an effect of Si on HIPVs. In this study, we tested the effect of Si supplementation versus Si deprivation to rice plants on subsequent HIPV production following feeding by the important pest, rice leaffolder (Cnaphalocrocis medinalis). Gas chromatography-mass spectrometry analyses showed lower production of α-bergamotene, β-sesquiohellandrene, hexanal 2-ethyl, and cedrol from +Si herbivore-infested plants compared with -Si infested plants. These changes in plant chemistry were ecologically significant in altering the extent to which parasitoids were attracted to infested plants. Adult females of Trathala flavo-orbitalis and Microplitis mediator both exhibited greater attraction to the HIPV blend of +Si plants infested with their respective insect hosts compared to -Si infested plants. In equivalent studies using RNAi rice plants in which jasmonate perception was silenced there was no equivalent change to the HIPV blend associated with Si treatment; indicating that the effects of Si on HIPVs are modulated by the jasmonate pathway. Further, this work demonstrates that silicon alters the HIPV blend of herbivore-infested rice plants. The significance of this finding is that there are no earlier-published studies of this phenomenon in rice or any other plant species. Si treatment to crops offers scope for enhancing induced, indirect defenses and associated biological control of pests because parasitoids are more strongly attracted by the HIPVs produced by +Si plants.

  8. Risk of Egg Parasitoid Attraction Depends on Anti-aphrodisiac Titre in the Large Cabbage White Butterfly Pieris brassicae

    NARCIS (Netherlands)

    Huigens, M.E.; Swart, de E.; Mumm, R.

    2011-01-01

    Males of a variety of insects transfer an anti-aphrodisiac pheromone to females during mating that renders them less attractive to conspecific males. In cabbage white butterflies, the transfer of an anti-aphrodisiac can result in the unwanted attraction of tiny egg parasitoid wasps of the genus

  9. Bee species-specific nesting material attracts a generalist parasitoid: implications for co-occurring bees in nest box enhancements.

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    Macivor, J Scott; Salehi, Baharak

    2014-08-01

    Artificial nests (e.g., nest boxes) for bees are increasingly being used to contribute to nesting habitat enhancement for bees that use preexisting cavities to provision brood. They usually incorporate additional nesting materials that vary by species. Cavity-nesting bees are susceptible to brood parasitoids that recognize their host(s) using visual and chemical cues. Understanding the range of cues that attract parasitoids to bee nests, including human-made analogues, is important if we wish to control parasitism and increase the potential value of artificial nests as habitat-enhancement strategies. In this study, we investigated the cues associated with the orientation of the generalist brood parasitoid Monodontomerus obscurus Westwood (Hymenoptera: Torymidae) to the nests of a common cavity-nesting resin bee Megachile campanulae (Robertson) (Megachilidae). The parasitoids were reared from previously infested M. campanulae brood cells and placed into choice trials where they were presented with pairs of different nest material cues. Among different materials tested, we found that Mo. obscurus was most attracted to fresh resin collected directly from Pinus strobus trees followed by previously used resin collected from the bee nest. The parasitoid also attacked other bee species in the same nest boxes, including those that do not use resin for nesting. Our findings suggest that M. campanulae could act as a magnet, drawing parasites away from other bee hosts co-occurring in nest boxes, or, as an attractant of Mo. obscurus to nest boxes, increasing attacks on co-occurring host bee species, potentially undermining bee diversity enhancement initiatives.

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

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    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.

  11. Exceptional Use of Sex Pheromones by Parasitoids of the Genus Cotesia: Males Are Strongly Attracted to Virgin Females, but Are No Longer Attracted to or Even Repelled by Mated Females

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    Hao Xu

    2014-06-01

    Full Text Available Sex pheromones have rarely been studied in parasitoids, and it remains largely unknown how male and female parasitoids locate each other. We investigated possible attraction (and repellency between the sexes of two braconid wasps belonging to the same genus, the gregarious parasitoid, Cotesia glomerata (L., and the solitary parasitoid, Cotesia marginiventris (Cresson. Males of both species were strongly attracted to conspecific virgin females. Interestingly, in C. glomerata, the males were repelled by mated females, as well as by males of their own species. This repellency of mated females was only evident hours after mating, implying a change in pheromone composition. Males of C. marginiventris were also no longer attracted, but not repelled, by mated females. Females of both species showed no attraction to the odors of conspecific individuals, male or female, and C. glomerata females even appeared to be repelled by mated males. Moreover, the pheromones were found to be highly specific, as males were not attracted by females of the other species. Males of Cotesia glomerata even avoided the pheromones of female Cotesia marginiventris, indicating the recognition of non-conspecific pheromones. We discuss these unique responses in the context of optimal mate finding strategies in parasitoids.

  12. Signal transduction downstream of salicylic and jasmonic acid in herbivory-induced parasitoid attraction by Arabidopsis is independent of JAR1 and NPR1

    NARCIS (Netherlands)

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

    2003-01-01

    Plants can defend themselves indirectly against herbivores by emitting a volatile blend upon herbivory that attracts the natural enemies of these herbivores, either predators or parasitoids. Although signal transduction in plants from herbivory to induced volatile production depends on jasmonic acid

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

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    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.

  14. Differential effects of flower feeding in an insect host–parasitoid system

    OpenAIRE

    Kehrli, Patrik; Bacher, Sven

    2008-01-01

    In many insect host–parasitoid systems, both the host and its parasitoids forage on shared floral resources. As a result of insect behaviour, morphology and physiology, flower species may act selectively at different levels of such systems, e.g., between the trophic levels of hosts and parasitoids, between species within a guild, between sexes or individuals within a species or between life history traits within an individual. We asked if effects of selectivity are consistent across levels in...

  15. Effects of student physical attractiveness

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    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.

  16. 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,

  17. Attraction of egg-killing parasitoids toward induced plant volatiles in a multi-herbivore context

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    Cusumano, A.; Weldegergis, B.T.; Colazza, S.; Dicke, M.; Fatouros, N.E.

    2015-01-01

    In response to insect herbivory, plants emit volatile organic compounds which may act as indirect plant defenses by attracting natural enemies of the attacking herbivore. In nature, plants are often attacked by multiple herbivores, but the majority of studies which have investigated indirect plant

  18. 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...

  19. Plant-mediated indirect effects and the persistence of parasitoid-herbivore communities

    NARCIS (Netherlands)

    Vos, M.; Berrocal, S.M.; Karamaouna, F.; Hemerik, L.; Vet, L.E.M.

    2001-01-01

    We have examined the effects of herbivore diversity on parasitoid community persistence and stability mediated by nonspecific information from herbivore-infested plants. First, we investigated host location and patch time allocation in the parasitoid Cotesia glomerata in environments where host

  20. Plant-mediated indirect effects and the persistence of parasitoid-herbivore communities

    NARCIS (Netherlands)

    Vos, M.; Berrocal, S.M.; Karamaouna, F.; Hemerik, L.; Vet, L.E.M.

    2001-01-01

    We have examined the effects of herbivore diversity on parasitoid community persistence and stability, mediated by nonspecific information from herbivore-infested plants. First, we investigated host location and patch time allocation in the parasitoid Cotesia glomerata in environments where host

  1. Impact of botanical pesticides derived from Melia azedarach and Azadirachta indica plants on the emission of volatiles that attract Parasitoids of the diamondback moth to cabbage plants.

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    Charleston, Deidre S; Gols, Rieta; Hordijk, Kees A; Kfir, Rami; Vet, Louise E M; Dicke, Marcel

    2006-02-01

    Herbivorous and carnivorous arthropods use chemical information from plants during foraging. Aqueous leaf extracts from the syringa tree Melia azedarach and commercial formulations from the neem tree Azadirachta indica, Neemix 4.5, were investigated for their impact on the flight response of two parasitoids, Cotesia plutellae and Diadromus collaris. Cotesia plutellae was attracted only to Plutella xylostella-infested cabbage plants in a wind tunnel after an oviposition experience. Female C. plutellae did not distinguish between P. xylostella-infested cabbage plants treated with neem and control P. xylostella-infested plants. However, females preferred infested cabbage plants that had been treated with syringa extract to control infested plants. Syringa extract on filter paper did not attract C. plutellae. This suggests that an interaction between the plant and the syringa extract enhances parasitoid attraction. Diadromus collaris was not attracted to cabbage plants in a wind tunnel and did not distinguish between caterpillar-damaged and undamaged cabbage plants. Headspace analysis revealed 49 compounds in both control cabbage plants and cabbage plants that had been treated with the syringa extract. Among these are alcohols, aldehydes, ketones, esters, terpenoids, sulfides, and an isothiocyanate. Cabbage plants that had been treated with the syringa extract emitted larger quantities of volatiles, and these increased quantities were not derived from the syringa extract. Therefore, the syringa extract seemed to induce the emission of cabbage volatiles. To our knowledge, this is the first example of a plant extract inducing the emission of plant volatiles in another plant. This interesting phenomenon likely explains the preference of C. plutellae parasitoids for cabbage plants that have been treated with syringa extracts.

  2. Mechanisms Underlying the Nonconsumptive Effects of Parasitoid Wasps on Aphids.

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    Ingerslew, K S; Finke, D L

    2017-02-01

    Natural enemies need not consume herbivores to suppress herbivore populations. Behavioral interactions can adversely impact herbivore fitness from reduced time feeding, investment in defense, or injury from failed attacks. The importance of such "nonconsumptive effects" for herbivore suppression may vary across species based on the specificity and intensity of the herbivore defensive response. In a series of manipulative studies, we quantified the nature and consequences of nonconsumptive interactions between two parasitoid wasps, Aphidius ervi Haliday and Aphidius colemani Viereck, on two aphid species, pea aphids (Acyrthosiphon pisum (Harris)) and green peach aphids (Myzus persicae (Sulzer)). Both wasps successfully parasitize green peach aphids, but only A. ervi parasitizes pea aphids. We observed A. ervi antennating and stinging pea aphids and documented a decrease in pea aphid longevity in response to stinging even when the aphid survived the interaction and no mummy formed. The primary defensive tactic of pea aphids in response to either wasp species was dropping from the host plant. Both wasp species antennated and stung green peach aphids, but they elicited unique defensive behaviors. Green peach aphids kicked or emitted cornicle secretions in response to A. colemani but spent more time off the plant in the presence of A. ervi. Green peach aphid longevity and fecundity were not affected by wasp stings when the aphid survived and no mummy formed. Our study demonstrates the complexity of behavioral interactions between parasitoids and their potential hosts and contributes to a mechanistic understanding of variation in the nonconsumptive suppression of herbivore populations. © The Authors 2016. Published by Oxford University Press on behalf of Entomological Society of America. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  3. Maize plants sprayed with either jasmonic acid or its precursor, methyl linolenate, attract armyworm parasitoids, but the composition of attractants differs

    NARCIS (Netherlands)

    Ozawa, R.; Shiojiri, K.; Sabelis, M.W.; Takabayashi, J.

    2008-01-01

    Treatment of both uninfested and armyworm-infested maize plants with jasmonic acid (JA) is known to attract the parasitic wasp, Cotesia kariyai Watanabe (Hymenoptera: Braconidae). Here, we show that treatment with a methyl ester of a JA precursor, methyl linolenate (MeLin), also causes maize plants

  4. Smelling the wood from the trees: Non-linear parasitoid responses to volatile attractants produced by wild and cultivated cabbage

    NARCIS (Netherlands)

    Gols, R.; Bullock, J.M.; Dicke, M.; Bukovinszky, T.; Harvey, J.A.

    2011-01-01

    Despite a large number of studies on herbivore-induced plant volatiles (HIPVs), little is known about which specific compounds are used by natural enemies to locate prey- or host- infested plants. In addition, the role of HIPVs in attracting natural enemies has been restricted largely to

  5. Smelling the Wood from the Trees: Non-Linear Parasitoid Responses to Volatile Attractants Produced by Wild and Cultivated Cabbage

    NARCIS (Netherlands)

    Gols, R.; Bullock, J.M.; Dicke, M.; Bukovinszky, T.; Harvey, J.A.

    2011-01-01

    Despite a large number of studies on herbivoreinduced plant volatiles (HIPVs), little is known about which specific compounds are used by natural enemies to locate prey- or host- infested plants. In addition, the role of HIPVs in attracting natural enemies has been restricted largely to agricultural

  6. Investigation of the lethal and behavioral effects of commercial insecticides on the parasitoid wasp Copidosoma truncatellum.

    Science.gov (United States)

    Ramos, Rodrigo S; de Araújo, Vitor C R; Pereira, Renata R; Martins, Júlio C; Queiroz, Obiratanea S; Silva, Ricardo S; Picanço, Marcelo C

    2018-01-01

    Copidosoma truncatellum (Hymenoptera: Encyrtidae) is an important parasitoid wasp of the soybean looper, Chrysodeixis includens, but its effectiveness can be severely curtailed by the application of certain insecticides. Therefore, to identify insecticides that are potentially compatible with C. truncatellum, the lethal and behavioral effects of nine chemicals used to control the soybean looper were evaluated for their toxicity to the wasp. Chlorantraniliprole, chlorfenapyr, flubendiamide, and indoxacarb were the least toxic insecticides to the parasitoid, resulting in mortalities of less than 25%. In contrast, cartap, deltamethrin, and methomyl caused 100% mortality, and acephate and spinosad caused 76% and 78% mortality, respectively. At least one of the detoxifying enzymes (monooxygenase, glutathione S-transferase, and/or esterases) may be involved in the mechanisms underlying the selectivity of chlorantraniliprole, chlorfenapyr, flubendiamide, and indoxacarb for the parasitoid based on the results for the insecticide plus synergist treatment. Changes in the behavioral patterns (walking time and resting time) of the parasitoid were found with exposure to acephate, flubendiamide, indoxacarb and methomyl, but behavioral avoidance was not observed. Our results indicate that the insecticides chlorantraniliprole and chlorfenapyr are the most suitable for inclusion in integrated pest management strategies for the control of C. includens. Copyright © 2017 Elsevier Ltd. All rights reserved.

  7. 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

  8. 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.

  9. The moderating effect of stimulus attractiveness on the effect of alcohol consumption on attractiveness ratings.

    Science.gov (United States)

    Chen, Xiong; Wang, Xiaoyu; Yang, Dong; Chen, Youguo

    2014-01-01

    To explore the enhancing effect of alcohol consumption on attractiveness ratings, in that few studies on the Beer Goggles effect control the stimuli attractiveness level and researchers have seldom considered extending the effect to stimuli other than faces. Male and female participants (n = 103) were randomly assigned to alcohol consumption or placebo groups. Both groups were asked to assess the attractiveness of two types of pictures (faces and landscapes) with three levels of attractiveness for each stimulus category (high, moderate and low). We found significant interactions between beverage type and attractiveness level. Attractiveness ratings for moderate- and low-attractiveness faces were significantly higher in the alcohol compared with placebo condition, while there was no significant difference for high-attractiveness stimuli between these two conditions. As for landscapes, only low-attractiveness stimuli were rated significantly higher in the alcohol condition. Whether or not alcohol consumption leads to an increase in attractiveness ratings depends on the initial attractiveness of the stimulus materials. Alcohol consumption tends to affect ratings for stimuli with relatively low attractiveness. Furthermore, this effect is not limited to faces; it extends to other types of stimuli like landscapes. © The Author 2014. Medical Council on Alcohol and Oxford University Press. All rights reserved.

  10. Effect of Maruca vitrata (Lepidoptera: Crambidae) host plants on life-history parameters of the parasitoid Apanteles taragamae (Hymenoptera: Braconidae)

    NARCIS (Netherlands)

    Dannon, A.E.; Tamo, M.; Agboton, C.; Huis, van A.; Dicke, M.

    2012-01-01

    The effect of four host plant species of the herbivore Maruca vitrata Fabricius (Lepidoptera: Crambidae) on development time, longevity, fecundity and sex ratio of the parasitoid Apanteles taragamae Viereck (Hymenoptera: Braconidae) was investigated under laboratory conditions. The larvae were

  11. Sublethal effects of imidacloprid on the whitefly parasitoid Encarsia formosa Gahan

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    Drobnjaković Tanja

    2017-01-01

    Full Text Available Acute toxicity of an imidacloprid-based product (Confidor 200 SL to pupae of the whitefly parasitoid Encarsia formosa Gahan (Hymenoptera: Aphelinidae, and its effects on life history traits and population growth in F1 generation of the surviving parasitoid females of a commercial strain ('Dutch' strain, D and two local populations from Serbia (Bujanovac, B; Negotin, N were examined in laboratory bioassays. All trials were carried out at 27±1°C temperature and 60±10% relative humidity, and under 16/8 h daylight/darkness photoperiod in four replications. In acute toxicity bioassays, tobacco leaves carrying parasitoid pupae were treated with a series of symmetrical concentrations (800, 400, 200, 100, 50 and 25 mg a.i./l covering a 10-90% mortality range. The product based on imidacloprid, applied directly onto parasitoid pupae at mean lethal concentrations (LC50 determined in the acute toxicity assays (30 mg/l, 20 mg/l and 25 mg/l, for populations B, N and D, respectively, significantly affected the survival of females developed from the treated pupae, extended the duration of juvenile development (by 1.81, 1.59 and 1.73 days for populations B, N and D, respectively, significantly reduced total parasitism of females D (25.92 %, total female adult emergence in populations B (27.48 % and D (17.92 %, and significantly reduced the instantaneous rate of increased only of females N (4.23 %. Considering the high acute toxicity of the imidacloprid product to the pupal stage of E. formosa, and significant reductions in life table and population parameters, imidacloprid is not considered compatible for simultaneous use with the parasitoid E. formosa. A more precise assessment of risks involved in the use of that insecticide requires a more detailed testing in the field. The implications of these results for the concept of integrated control of the greenhouse whitefly are discussed.

  12. Effects of aposymbiotic and symbiotic aphids on parasitoid progeny development and adult oviposition behavior within aphid instars.

    Science.gov (United States)

    Cheng, Rui-Xia; Meng, Ling; Li, Bao-Ping

    2010-04-01

    This study aims at exploring the potential relationship between aphidiine parasitoid development and the primary endosymbiont in aphids by focusing on specific aphid instars and the relative effects on parasitoid oviposition behavior and progeny development. Lysiphlebus ambiguus (Aphidiidae, Hymenoptera) is a solitary parasitoid of several species of aphids, including Aphis fabae. In this study, A. fabae was treated with antibiotic rifampicin to obtain aposymbiotic hosts and exposed to parasitism. L. ambiguus launched significantly more attacks on symbiotic L(2) (the second instar), aposymbiotic L(3) (the third instar) and L(4) (the forth instar) hosts than on the corresponding hosts at the same age. L. ambiguus also parasitized more L(1) aphids compared with adults irrespective of whether the aphid was asymbiotic or not. Pupa mortality rate of parasitoid progeny was significantly lower from aposymbiotic hosts than from the corresponding symbiotics at all stages. Female-biased parasitoid progeny was produced from aposymbiotic aphids without respect to host ages, but female progeny increased linearly with host ages at parasitism from symbiotic aphids. Body size of parasitoid progeny increased linearly with host instars at parasitism in symbiotic aphids but did not significantly change across host instars in aposymbiotic aphids. The offspring parasitoids turned out to be generally large in body size from attacking aposymbiotic aphids compared with the symbiotics. Development time of egg-to-adult of parasitoid progeny decreased with host instars in both symbiotic and aposymbiotic aphids but was generally much longer in aposymbiotic aphids than in symbiotic aphids. Our study suggests that age or body size of host aphids may not be the only cue exercised by L. ambiguus to evaluate host quality and that offspring parasitoids may be able to compensate for the nutrition stress associated with disruption of primary endosymbiotc bacteria in aposymbiotic aphids.

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

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    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.

  14. 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. Published by Elsevier Ltd.

  15. The Attraction Effect in Information Visualization.

    Science.gov (United States)

    Dimara, Evanthia; Bezerianos, Anastasia; Dragicevic, Pierre

    2017-01-01

    The attraction effect is a well-studied cognitive bias in decision making research, where one's choice between two alternatives is influenced by the presence of an irrelevant (dominated) third alternative. We examine whether this cognitive bias, so far only tested with three alternatives and simple presentation formats such as numerical tables, text and pictures, also appears in visualizations. Since visualizations can be used to support decision making - e.g., when choosing a house to buy or an employee to hire - a systematic bias could have important implications. In a first crowdsource experiment, we indeed partially replicated the attraction effect with three alternatives presented as a numerical table, and observed similar effects when they were presented as a scatterplot. In a second experiment, we investigated if the effect extends to larger sets of alternatives, where the number of alternatives is too large for numerical tables to be practical. Our findings indicate that the bias persists for larger sets of alternatives presented as scatterplots. We discuss implications for future research on how to further study and possibly alleviate the attraction effect.

  16. 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).

  17. Attraction effects in honorific agreement in Korean

    Directory of Open Access Journals (Sweden)

    Nayoung Kwon

    2016-08-01

    Full Text Available Previous studies have suggested that sentence processing is mediated by content-addressable direct retrieval processes (McElree, 2000; McElree, Foraker, & Dyer, 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 (Dillon, Mishler, Sloggett, & Phillips, 2013; Pearlmutter, Garnsey & Bock, 1999; Xiang, Dillon, & Phillips, 2009, studies investigating reflexives have not found consistent evidence of intrusion effects (Parker & Lago, & Phillips, 2015; Sturt & Kwon, 2015; cf. Nicol & Swinney, 1989; Sturt, 2003. Similarly, the memory retrieval processes could be also sensitive to cross-linguistic differences (cf. Lago, Shalom, Sigman, Lau & Phillips, 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, Lau & Phillips, 2009, but is likely also to result from general mechanisms of retrieval processes of activating of potential items in memory (Vasishth, Br

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

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    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.

  19. Time allocation of a parasitoid foraging in heterogeneous vegetation: implications for host-parasitoid interactions

    NARCIS (Netherlands)

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

    2007-01-01

    1. Changing plant composition in a community can have profound consequences for herbivore and parasitoid population dynamics. To understand such effects, studies are needed that unravel the underlying behavioural decisions determining the responses of parasitoids to complex habitats. 2. The

  20. Specific bottom-up effects of arbuscular mycorrhizal fungi across a plant-herbivore-parasitoid system.

    Science.gov (United States)

    Hempel, Stefan; Stein, Claudia; Unsicker, Sybille B; Renker, Carsten; Auge, Harald; Weisser, Wolfgang W; Buscot, François

    2009-05-01

    The majority of plants are involved in symbioses with arbuscular mycorrhizal fungi (AMF), and these associations are known to have a strong influence on the performance of both plants and insect herbivores. Little is known about the impact of AMF on complex trophic chains, although such effects are conceivable. In a greenhouse study we examined the effects of two AMF species, Glomus intraradices and G. mosseae on trophic interactions between the grass Phleum pratense, the aphid Rhopalosiphum padi, and the parasitic wasp Aphidius rhopalosiphi. Inoculation with AMF in our study system generally enhanced plant biomass (+5.2%) and decreased aphid population growth (-47%), but there were no fungal species-specific effects. When plants were infested with G. intraradices, the rate of parasitism in aphids increased by 140% relative to the G. mosseae and control treatment. When plants were associated with AMF, the developmental time of the parasitoids decreased by 4.3% and weight at eclosion increased by 23.8%. There were no clear effects of AMF on the concentration of nitrogen and phosphorus in plant foliage. Our study demonstrates that the effects of AMF go beyond a simple amelioration of the plants' nutritional status and involve rather more complex species-specific cascading effects of AMF in the food chain that have a strong impact not only on the performance of plants but also on higher trophic levels, such as herbivores and parasitoids.

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

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    Khaled Abbes

    Full Text Available 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.

  2. 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

  3. The Effects of Physical Attractiveness and Anxiety on Heterosexual Attraction Over a Series of Five Encounters

    Science.gov (United States)

    Mathes, Eugene W.

    1975-01-01

    The "information availability model" of heterosexual attraction was tested by having subjects go on a series of five encounters. It was found that both physical attractiveness and the personality variable, anxiety, had early and continuous effects on liking. It was concluded the model is an inadequate explanation of heterosexual…

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

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    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.

  5. Parasitoid-specific induction of plant responses to parasitized herbivores affects colonization by subsequent herbivores.

    Science.gov (United States)

    Poelman, Erik H; Zheng, Si-Jun; Zhang, Zhao; Heemskerk, Nanda M; Cortesero, Anne-Marie; Dicke, Marcel

    2011-12-06

    Plants are exposed to a suite of herbivorous attackers that often arrive sequentially. Herbivory affects interactions between the host plants and subsequently attacking herbivores. Moreover, plants may respond to herbivory by emitting volatile organic compounds (VOCs) that attract carnivorous natural enemies of the herbivores. However, information borne by VOCs is ubiquitous and may attract carnivores, such as parasitoids, that differ in their effectiveness at releasing the plant from its herbivorous attackers. Furthermore, the development of parasitoids within their herbivorous hosts, attacking a given host plant, may influence the elicitation of defensive reactions in the host plant. This may, in turn, affect the behavior of subsequent herbivores attacking the host plant. Here, we show that the species identity of a parasitoid had a more significant effect on defense responses of Brassica oleracea plants than the species identity of the herbivorous hosts of the parasitoids. Consequently, B. oleracea plants that were damaged by caterpillars (Pieris spp.) parasitized by different parasitoid species varied in the degree to which diamondback moths (Plutella xylostella) selected the plants for oviposition. Attracting parasitoids in general benefitted the plants by reducing diamondback moth colonization. However, the species of parasitoid that parasitized the herbivore significantly affected the magnitude of this benefit by its species-specific effect on herbivore-plant interactions mediated by caterpillar regurgitant. Our findings show that information-mediated indirect defense may lead to unpredictable consequences for plants when considering trait-mediated effects of parasitized caterpillars on the host plant and their consequences because of community-wide responses to induced plants.

  6. Context-dependent fitness effects of behavioral manipulation by a parasitoid

    NARCIS (Netherlands)

    Janssen, A.; Grosman, A.H.; Cordeiro, E.G.; de Brito, E.F.; Fonseca, J.O.; Colares, F.; Pallini, A.; Lima, E.R.; Sabelis, M.W.

    2010-01-01

    Many true parasites and parasitoids modify the behavior of their host, and most of these changes are thought to benefit the parasites. However, field tests of this hypothesis are scarce. We previously showed that braconid parasitoids (Glyptapanteles sp.) induce their caterpillar host (Thyrinteina

  7. 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.

  8. Asymmetric Effect of Expression Intensity on Evaluations of Facial Attractiveness

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    Ryuhei Ueda

    2016-11-01

    Full Text Available Many studies have shown that facial expression influences evaluations of attractiveness, but the effect of expression intensity remains unclear. In the present study, participants rated the expression intensity and attractiveness of faces with happy, neutral, or sad expressions. Sad faces, as anticipated, were judged as less attractive than neutral and happy faces. Among happy expressions, faces with more intense expressions were considered more attractive; for sad expressions, there was no significant relationship between rating and intensity. Multiple regression analyses further demonstrated that the attractiveness of a face with a sad expression could be predicted only by its baseline attractiveness (i.e., ratings of neutral expressions. We conclude that the intensity of positive and negative expressions asymmetrically influences evaluations of the attractiveness of a face. We discuss the results in terms of emotional contagion or sympathy.

  9. Trans-Generational Effects of Mild Heat Stress on the Life History Traits of an Aphid Parasitoid

    Science.gov (United States)

    Ismaeil, Ibrahim; Doury, Géraldine; Desouhant, Emmanuel; Dubois, Françoise; Prevost, Geneviève; Couty, Aude

    2013-01-01

    Temperature changes are common in nature and insects are particularly exposed and sensitive to such variations which can be potential stresses, ultimately affecting life history traits and overall fitness. Braconids have been widely used to study the effects of temperature on host-parasitoid interactions and the present work focused on the solitary endoparasitoid Aphidius ervi Haliday (Hymenoptera: Braconidae Aphidiidae), an efficient biological control agent commercially used against aphids such as the potato aphid Macrosiphum euphorbiae Thomas (Sternorrhyncha: Aphididae). Contrary to previous studies using heat shocks at extreme temperatures, we evaluated the effects of mild heat stresses by transferring young parasitoid adults from the constant temperature of 20°C to either a warm (25°C) or hot (28°C) temperature, for either 1 h or 48 h. Such treatments are consistent with situations commonly experienced by parasitoids when moved from their rearing conditions to greenhouses or field conditions. The effects were evaluated both on the heat stressed A. ervi adults (G0) (immediate effects) and on their first generation (G1) progeny (trans-generational effects). G0 wasps’ mortality was significantly affected by the temperature in interaction with the duration of the stress. Longevity of G0 wasps surviving the heat stress was negatively affected by the temperature and females lived longer than males. Heat stress applied to A. ervi parents also had consequences on their G1 progeny whose developmental time, rates of mummification and percentage of parasitoid completing total development were negatively affected. Surprisingly, the egg load at emergence of the G1 female progeny was increased when their mothers had been submitted to a mild heat stress of 25°C or 28°C. These results clearly demonstrate trans-generational phenotypic plasticity, showing that adaptation to thermal stresses may be achieved via maternal effects. This study also sheds light on the

  10. Trans-generational effects of mild heat stress on the life history traits of an aphid parasitoid.

    Directory of Open Access Journals (Sweden)

    Ibrahim Ismaeil

    Full Text Available Temperature changes are common in nature and insects are particularly exposed and sensitive to such variations which can be potential stresses, ultimately affecting life history traits and overall fitness. Braconids have been widely used to study the effects of temperature on host-parasitoid interactions and the present work focused on the solitary endoparasitoid Aphidius ervi Haliday (Hymenoptera: Braconidae Aphidiidae, an efficient biological control agent commercially used against aphids such as the potato aphid Macrosiphum euphorbiae Thomas (Sternorrhyncha: Aphididae. Contrary to previous studies using heat shocks at extreme temperatures, we evaluated the effects of mild heat stresses by transferring young parasitoid adults from the constant temperature of 20°C to either a warm (25°C or hot (28°C temperature, for either 1 h or 48 h. Such treatments are consistent with situations commonly experienced by parasitoids when moved from their rearing conditions to greenhouses or field conditions. The effects were evaluated both on the heat stressed A. ervi adults (G0 (immediate effects and on their first generation (G1 progeny (trans-generational effects. G0 wasps' mortality was significantly affected by the temperature in interaction with the duration of the stress. Longevity of G0 wasps surviving the heat stress was negatively affected by the temperature and females lived longer than males. Heat stress applied to A. ervi parents also had consequences on their G1 progeny whose developmental time, rates of mummification and percentage of parasitoid completing total development were negatively affected. Surprisingly, the egg load at emergence of the G1 female progeny was increased when their mothers had been submitted to a mild heat stress of 25°C or 28°C. These results clearly demonstrate trans-generational phenotypic plasticity, showing that adaptation to thermal stresses may be achieved via maternal effects. This study also sheds light on

  11. Toxicity of Piper aduncum (Piperaceae) Essential Oil Against Euschistus heros (F.) (Hemiptera: Pentatomidae) and Non-Effect on Egg Parasitoids.

    Science.gov (United States)

    Turchen, L M; Piton, L P; Dall'Oglio, E L; Butnariu, A R; Pereira, M J B

    2016-10-01

    Plant essential oils have been recognized as significant natural resources for insecticides. Herein, we have assessed the toxicity of the essential oil of Piper aduncum (Piperaceae) against Euschistus heros (F.) (Hemiptera: Pentatomidae), a key soybean pest in Neotropical America. In addition, we have assessed its effect on the performance of egg parasitoids. The essential oil was obtained from the leaves of P. aduncum via hydrodistillation. Subsequently, bioassays of the concentration response to eggs (contact and immersion methods), nymphs, and adults (topical application) were conducted, to assess the lethal effects on the stink bug. We also evaluated the performance of parasitism and adult emergence of egg parasitoids, when the host eggs were treated with essential oil. In the egg bioassay, both exposure methods were efficient for unviable eggs (immersion LC50 = 15.64 mg mL-1; contact LC50 = 21.29 mg mL-1), with the highlight on the immersion method. The bioassay with nymphs indicated a higher toxicity of essential oil, with lower concentrations (LC50 = 11.37 mg mL-1) being required to cause the death of insects. For adults, a reduction in survival of insects was observed, and consequently, there was a reduction in the number of individuals in the next generation. Although the essential oil was toxic to E. heros, it exhibited lower toxicity for egg parasitoids, as there was no effect on parasitism and the emergence of wasps. We discuss likely explanations for such selectivity. In summary, we found that the essential oil was promising for the control of E. heros, because it caused deleterious effects at all development stages of the stink bug and had no effect on parasitism and emergence of the egg parasitoids, which suggested compatibility with biological control.

  12. 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.

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

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    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.

  14. 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...

  15. The Effect of Professor's Attractiveness On Distance Learning Students

    Directory of Open Access Journals (Sweden)

    Jeanny Liu

    2015-07-01

    Full Text Available 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 professors on business students enrolled in distance learning courses. This study expands on prior studies by testing whether the attractiveness of the professor matters to student learning within the context of online learning environment. A total of 122 online business students were surveyed. Our findings suggest that professor’s attractiveness has a statistically significant effect on student learning, motivation, and satisfaction. In addition, online students perceived attractive professors with more expertise as an instructor. Female students had higher motivation than male students. Furthermore, separate analysis indicated that attractiveness effects were stronger for participants over the age 46 when compared to other groups.

  16. Genetic engineering of plant volatile terpenoids: effects on a herbivore, a predator and a parasitoid.

    Science.gov (United States)

    Kos, Martine; Houshyani, Benyamin; Overeem, Aart-Jan; Bouwmeester, Harro J; Weldegergis, Berhane T; van Loon, Joop J A; Dicke, Marcel; Vet, Louise E M

    2013-02-01

    Most insect-resistant transgenic crops employ toxins to control pests. A novel approach is to enhance the effectiveness of natural enemies by genetic engineering of the biosynthesis of volatile organic compounds (VOCs). Before the commercialisation of such transgenic plants can be pursued, detailed fundamental studies of their effects on herbivores and their natural enemies are necessary. The linalool/nerolidol synthase gene FaNES1 was constitutively expressed from strawberry in three Arabidopsis thaliana accessions, and the behaviour of the aphid Brevicoryne brassicae L., the parasitoid Diaeretiella rapae McIntosh and the predator Episyrphus balteatus de Geer was studied. Transgenic FaNES1-expressing plants emitted (E)-nerolidol and larger amounts of (E)-DMNT and linalool. Brevicoryne brassicae was repelled by the transgenic lines of two of the accessions, whereas its performance was not affected. Diaeretiella rapae preferred aphid-infested transgenic plants over aphid-infested wild-type plants for two of the accessions. In contrast, female E. balteatus predators did not differentiate between aphid-infested transgenic or wild-type plants. The results indicate that the genetic engineering of plants to modify their emission of VOCs holds considerable promise for facilitating biological control of herbivores. Validation for crop plants is a necessary next step to assess the usefulness of modified volatile emission in integrated pest management. Copyright © 2012 Society of Chemical Industry.

  17. Effects of Switching Behavior for the Attraction on Pedestrian Dynamics.

    Science.gov (United States)

    Kwak, Jaeyoung; Jo, Hang-Hyun; Luttinen, Tapio; Kosonen, Iisakki

    2015-01-01

    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 in their desired direction. These collective patterns of pedestrian behavior are summarized in a phase diagram by comparing the number of pedestrians who visited the attraction to the number of passersby near the attraction. Measuring the marginal benefits with respect to the strength of the social influence and the average length of stay enables us to identify under what conditions enhancing these variables would be more effective. The findings from this study can be understood in the context of the pedestrian facility management, for instance, for retail stores.

  18. Effects of Switching Behavior for the Attraction on Pedestrian Dynamics.

    Directory of Open Access Journals (Sweden)

    Jaeyoung Kwak

    Full Text Available 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 in their desired direction. These collective patterns of pedestrian behavior are summarized in a phase diagram by comparing the number of pedestrians who visited the attraction to the number of passersby near the attraction. Measuring the marginal benefits with respect to the strength of the social influence and the average length of stay enables us to identify under what conditions enhancing these variables would be more effective. The findings from this study can be understood in the context of the pedestrian facility management, for instance, for retail stores.

  19. 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.

  20. The Effect of Professor's Attractiveness On Distance Learning Students

    OpenAIRE

    Jeanny Liu; Stella D. Tomasi

    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 professors on business students enrolled in distance learning courses. This study expands on prior studies by testing whether the attractiveness of the ...

  1. Parasitoids and dipteran predators exploit volatiles from microbial symbionts to locate bark beetles.

    Science.gov (United States)

    Boone, Celia K; Six, Diana L; Zheng, Yanbing; Raffa, Kenneth F

    2008-02-01

    Host location by parasitoids and dipteran predators of bark beetles is poorly understood. Unlike coleopteran predators that locate prey by orienting to prey pheromones, wasps and flies often attack life stages not present until after pheromone production ceases. Bark beetles have important microbial symbionts, which could provide sources of cues. We tested host trees, trees colonized by beetles and symbionts, and trees colonized by symbionts alone for attractiveness to hymenopteran parasitoids and dipteran predators. Field studies were conducted with Ips pini in Montana. Three pteromalid wasps were predominant. All were associated with the second and third instars of I. pini. Heydenia unica was more attracted to logs colonized by either I. pini or the fungus Ophiostoma ips than logs alone or blank controls (screen with no log). Rhopalicus pulchripennis was more attracted to logs colonized by I. pini than logs alone or blank controls. Dibrachys cavus was attracted to logs but did not distinguish whether or not they were colonized. Two dolichopodid predators were predominant. A Medetera species was more attracted to colonized than uncolonized logs and more attracted to logs than blank controls. It was also more attracted to logs colonized with the yeast Pichia scolyti than uncolonized logs, but attraction was less consistent. An unidentified dolichopodid was more attracted to logs colonized with I. pini, O. ips, and the bacteria Burkholderia sp., than to uncolonized logs. It was also attracted to uncolonized logs. Its responses were less consistent and pronounced than H. unica. These results suggest some parasitoids and dipteran predators exploit microbial symbionts of bark beetles to locate hosts. Overall, specialists showed strong attraction to fungal cues, whereas generalists were more attracted by plant volatiles. These results also show how microbial symbionts can have conflicting effects on host fitness.

  2. The Effect of Molecular Structure on Olfactory Discrimination by the Parasitoid Microplitis croceipes

    NARCIS (Netherlands)

    Meiners, T.; Wäckers, F.L.; Lewis, W.J.

    2002-01-01

    Flight chamber experiments were conducted to examine the capacity of the larval parasitoid Microplitis croceipes (Hymenoptera: Braconidae) to learn to distinguish between structurally related aliphatic alcohols differing in the carbon chain-length and the position of the functional group, and

  3. The effect of molecular structure on olfactory discrimination by the parasitoid Microplitis croceipes

    NARCIS (Netherlands)

    Meiners, T.; Waeckers, F.; Lewis, W.J.

    2002-01-01

    Flight chamber experiments were conducted to examine the capacity of the larval parasitoid Microplitis croceipes (Hymenoptera: Braconidae) to learn to distinguish between structurally related aliphatic alcohols differing in the carbon chain-length and the position of the functional group, and

  4. Dietary Effects on Cuticular Hydrocarbons and Sexual Attractiveness in Drosophila

    Science.gov (United States)

    Fedina, Tatyana Y.; Kuo, Tsung-Han; Dreisewerd, Klaus; Dierick, Herman A.; Yew, Joanne Y.; Pletcher, Scott D.

    2012-01-01

    Dietary composition is known to have profound effects on many aspects of animal physiology, including lifespan, general health, and reproductive potential. We have previously shown that aging and insulin signaling significantly influence the composition and sexual attractiveness of Drosophila melanogaster female cuticular hydrocarbons (CHCs), some of which are known to be sex pheromones. Because diet is intimately linked to aging and to the activity of nutrient-sensing pathways, we asked how diet affects female CHCs and attractiveness. Here we report consistent and significant effects of diet composition on female CHC profiles across ages, with dietary yeast and sugar driving CHC changes in opposite directions. Surprisingly, however, we found no evidence that these changes affect female attractiveness. Multivariate comparisons among responses of CHC profiles to diet, aging, and insulin signaling suggest that diet may alter the levels of some CHCs in a way that results in profiles that are more attractive while simultaneously altering other CHCs in a way that makes them less attractive. For example, changes in short-chain CHCs induced by a high-yeast diet phenocopy changes caused by aging and by decreased insulin signaling, both of which result in less attractive females. On the other hand, changes in long-chain CHCs in response to the same diet result in levels that are comparable to those observed in attractive young females and females with increased insulin signaling. The effects of a high-sugar diet tend in the opposite direction, as levels of short-chain CHCs resemble those in attractive females with increased insulin signaling and changes in long-chain CHCs are similar to those caused by decreased insulin signaling. Together, these data suggest that diet-dependent changes in female CHCs may be sending conflicting messages to males. PMID:23227150

  5. Dietary effects on cuticular hydrocarbons and sexual attractiveness in Drosophila.

    Directory of Open Access Journals (Sweden)

    Tatyana Y Fedina

    Full Text Available Dietary composition is known to have profound effects on many aspects of animal physiology, including lifespan, general health, and reproductive potential. We have previously shown that aging and insulin signaling significantly influence the composition and sexual attractiveness of Drosophila melanogaster female cuticular hydrocarbons (CHCs, some of which are known to be sex pheromones. Because diet is intimately linked to aging and to the activity of nutrient-sensing pathways, we asked how diet affects female CHCs and attractiveness. Here we report consistent and significant effects of diet composition on female CHC profiles across ages, with dietary yeast and sugar driving CHC changes in opposite directions. Surprisingly, however, we found no evidence that these changes affect female attractiveness. Multivariate comparisons among responses of CHC profiles to diet, aging, and insulin signaling suggest that diet may alter the levels of some CHCs in a way that results in profiles that are more attractive while simultaneously altering other CHCs in a way that makes them less attractive. For example, changes in short-chain CHCs induced by a high-yeast diet phenocopy changes caused by aging and by decreased insulin signaling, both of which result in less attractive females. On the other hand, changes in long-chain CHCs in response to the same diet result in levels that are comparable to those observed in attractive young females and females with increased insulin signaling. The effects of a high-sugar diet tend in the opposite direction, as levels of short-chain CHCs resemble those in attractive females with increased insulin signaling and changes in long-chain CHCs are similar to those caused by decreased insulin signaling. Together, these data suggest that diet-dependent changes in female CHCs may be sending conflicting messages to males.

  6. Effects of parental socio-economic conditions on facial attractiveness.

    Science.gov (United States)

    Huber, Susanne; Fieder, Martin

    2014-12-30

    Socio-economic conditions during early life are known to affect later life outcomes such as health or social success. We investigated whether family socio-economic background may also affect facial attractiveness. We used the Wisconsin Longitudinal Study (n = 8434) to analyze the association between an individual's parental socio-economic background (in terms of father's highest education and parental income) and that individual's facial attractiveness (estimated by rating of high school yearbook photographs when subjects were between 17 and 20 years old), controlling for subjects' sex, year of birth, and father's age at subjects' birth. Subjects' facial attractiveness increased with increasing father's highest educational attainment as well as increasing parental income, with the latter effect being stronger for female subjects as well. We conclude that early socio-economic conditions predict, to some extent, facial attractiveness in young adulthood.

  7. Effects of Parental Socio-Economic Conditions on Facial Attractiveness

    Directory of Open Access Journals (Sweden)

    Susanne Huber

    2014-04-01

    Full Text Available Socio-economic conditions during early life are known to affect later life outcomes such as health or social success. We investigated whether family socio-economic background may also affect facial attractiveness. We used the Wisconsin Longitudinal Study (n = 8434 to analyze the association between an individual's parental socioeconomic background (in terms of father's highest education and parental income and that individual's facial attractiveness (estimated by rating of high school yearbook photographs when subjects were between 17 and 20 years old, controlling for subjects' sex, year of birth, and father's age at subjects' birth. Subjects' facial attractiveness increased with increasing father's highest educational attainment as well as increasing parental income, with the latter effect being stronger for female subjects as well. We conclude that early socio-economic conditions predict, to some extent, facial attractiveness in young adulthood.

  8. Effects of Associating with Musical Genres on Heterosexual Attraction.

    Science.gov (United States)

    Zillman, Dolf; Bhatia, Azra

    1989-01-01

    Studies the effect of musical preferences on undergraduate students' estimation of numerous behavioral traits and the desirability of a potential heterosexual date. Finds that such disclosure influences attraction, as well as the perception and evaluation of pertinent traits, the effects being a function of genre-specific stereotypes and…

  9. The Attraction Effect Modulates Reward Prediction Errors and Intertemporal Choices.

    Science.gov (United States)

    Gluth, Sebastian; Hotaling, Jared M; Rieskamp, Jörg

    2017-01-11

    Classical economic theory contends that the utility of a choice option should be independent of other options. This view is challenged by the attraction effect, in which the relative preference between two options is altered by the addition of a third, asymmetrically dominated option. Here, we leveraged the attraction effect in the context of intertemporal choices to test whether both decisions and reward prediction errors (RPE) in the absence of choice violate the independence of irrelevant alternatives principle. We first demonstrate that intertemporal decision making is prone to the attraction effect in humans. In an independent group of participants, we then investigated how this affects the neural and behavioral valuation of outcomes using a novel intertemporal lottery task and fMRI. Participants' behavioral responses (i.e., satisfaction ratings) were modulated systematically by the attraction effect and this modulation was correlated across participants with the respective change of the RPE signal in the nucleus accumbens. Furthermore, we show that, because exponential and hyperbolic discounting models are unable to account for the attraction effect, recently proposed sequential sampling models might be more appropriate to describe intertemporal choices. Our findings demonstrate for the first time that the attraction effect modulates subjective valuation even in the absence of choice. The findings also challenge the prospect of using neuroscientific methods to measure utility in a context-free manner and have important implications for theories of reinforcement learning and delay discounting. Many theories of value-based decision making assume that people first assess the attractiveness of each option independently of each other and then pick the option with the highest subjective value. The attraction effect, however, shows that adding a new option to a choice set can change the relative value of the existing options, which is a violation of the independence

  10. Effects of host deprivation and egg expenditure on the reproductive capacity of Mastrus ridibundus, an introduced parasitoid for the biological control of codling moth in California

    NARCIS (Netherlands)

    Hougardy, E.; Bezemer, T.M.; Mills, N.J.

    2005-01-01

    The effect of host deprivation and egg expenditure on egg load, realized fecundity, and parasitism of the ichneumonid Mastrus ridibundus, a gregarious parasitoid introduced for the control of codling moth in California, were investigated under laboratory conditions. Females deprived of hosts had a

  11. 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

    NARCIS (Netherlands)

    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

  12. Host suitability affects odor association in Cotesia marginiventris: implications in generalist parasitoid host-finding

    Science.gov (United States)

    Insect herbivores often induce plant volatile compounds that can attract natural enemies. Cotesia marginiventris (Hymenoptera: Braconidae) is a generalist parasitoid wasp of noctuid caterpillars and is highly attracted to Spodoptera exigua-induced plant volatiles. The plasticity of C. marginiventris...

  13. The effect of floral resources on parasitoid and host longevity: prospects for conservation biological control in strawberries.

    Science.gov (United States)

    Sigsgaard, Lene; Betzer, Cathrine; Naulin, Cyril; Eilenberg, Jørgen; Enkegaard, Annie; Kristensen, Kristian

    2013-01-01

    The strawberry tortricid, Acleris comariana Lienig and Zeller (Lepidoptera: Tortricidae) is an important pest in Danish strawberry production. Its most common parasitoid is Copidosoma aretas (Walker) (Hymenoptera: Chalcidoidea: Encyrtidae). To identify selective flowering plants that could be used to increase functional biodiversity, the longevity of C. aretas and its host A. comariana was assessed on 5 flowering species: buckwheat, Fagopyrum esculentum Moench (Caryophyllales: Polygonaceae); borage, Borago officinalis L. (Boraginaceae); strawberry, Fragaria x ananassa Duchesne (Rosales: Rosaceae); phacelia, Phacelia tanacetifolia Bentham (Boraginaceae); and dill, Anethum graveolens L. (Apiales: Apiaceae). Dill was only tested with C. aretas. Sucrose and pollen served as positive controls, and pure water as a negative control. In a subsequent field experiment, A. comariana larval density was assessed at 1, 6, and 11 m distances from buckwheat flower strips in 3 fields. The proportion of field-collected larvae that were parasitized by C. aretas or fungi was assessed. Among the tested floral diets, buckwheat was superior for C. aretas, increasing its longevity by 1.4 times compared to water. Although buckwheat also increased longevity of A. comariana, its longevity and survival on buckwheat, borage, and strawberry was not significantly different, so buckwheat was chosen for field experiments. A. comariana densities in the 3 fields with sown buckwheat flower strips were 0.5, 4.0, and 8.3 larvae per m per row of strawberry respectively. Of the collected larvae, a total of 1%, 39%, and 65% were parasitized by C. aretas, respectively. The density of A. comariana and the proportion parasitized by C. aretas were highly significantly correlated. Distance from floral strips had no significant effect on either A. comariana larval density or on the proportion of individuals parasitized by C. aretas. Few other parasitoids emerged from collected larvae, and no larvae were

  14. 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.

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

    Directory of Open Access Journals (Sweden)

    Antonio Biondi

    Full Text Available 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

  16. 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

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

    Directory of Open Access Journals (Sweden)

    Suvi Niemikapee

    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.

  18. 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...

  19. The Effect of Natural Space on Nearby Property Prices : Accounting for Perceived Attractiveness

    NARCIS (Netherlands)

    Daams, Michiel N.; Sijtsma, Frans J.; van der Vlist, Arno J.

    2016-01-01

    This paper estimates the effect of attractive natural space on Dutch residential property prices. We operationalize attractive natural spaces by combining land use data with unique data on the perceived attractiveness of natural spaces. In our main results, the effect of attractive natural space on

  20. 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.

  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. Examining the locus of the attentional attraction effect.

    Science.gov (United States)

    Chow, Amy; Gozli, Davood G; Pratt, Jay

    2014-11-01

    Our spatial perception is not always veridical. Indeed, systematic distortions in localization have been found to result from orienting of attention. Distorted localization is inferred from tasks wherein the subject reports the location of centrally presented parallel (vernier) line stimuli. Particularly, prior to the presentation of the lines, a shift of attention toward peripheral cues produces a mislocalization of the line stimuli away from the cues (termed the attentional repulsion effect [ARE]). However, if the shift of attention is induced after target presentation, by reversing the order of stimulus presentation, a substantial mislocalization toward the cues (attentional attraction effect [AAE]) is found. The purpose of this study was to identify whether the AAE arises from the modulation in the same processes as the ARE. While an interocular presentation of cues to one eye and vernier lines to the other was previously shown to eliminate the ARE, the AAE persists across both the interocular and monocular conditions (both the cues and vernier lines are presented to the same eye). Considering Ono and Watanabe's (2011) suggestion that memory traces may be involved in generating the AAE, this prospect was examined by having participants delay their response for a short (100 ms) or long (1,000 ms) period of time. The magnitude of AAE was larger with a longer delay, consistent with the involvement of visual memory. Next, to directly examine the role of spatial working memory, the attentional attraction task was embedded within either a spatial memory task (remembering the locations of one or three squares) or a color memory task (remembering the color of one or three squares). Only high spatial memory load reduced the magnitude of AAE. Our results suggest the AAE relies on changes to different visual processes than does the ARE and involves spatial working memory.

  3. Effect of temperatures and cold storage on performance of Tetrastichus brontispae (Hymenoptera: Eulophidae), a parasitoid of Brontispa longissima (Coleptera: Chrysomelidae).

    Science.gov (United States)

    Liu, Kui; Fu, Buli; Lin, Jiangrong; Fu, Yueguan; Peng, Zhengqiang; Jin, Qi'an

    2014-01-01

    Laboratory studies were conducted to determine the effect of temperature and cold storage on the performance of Tetrastichus brontispae (Ferriere) (Hymenoptera: Eulophidae), one of the major endoparasitoids against coconut hispine beetle, Brontispa longissima (Gestro) (Coleptera: Chrysomelidae). The results revealed that T. brontispae could successfully parasitize host pupae under all seven tested temperatures, but no adult emergence was observed at 32°C. It was also revealed that temperatures between 24 and 26°C appeared to be the optimum temperatures for parasitism, as these temperatures resulted in the most parasitized pupae and a significantly higher emergence rate and progeny production. These measurements significantly declined at 20, 30, and 32°C. This study confirmed developmental periods of parasitoid progeny decreased as the temperature increased, and sex ratio of this female-biased parasitoid was not affected by rearing temperatures. More importantly, this study indicated that cold storage of parasitized pupae could extend up to 30 d at 10°C, and a longer storage period had a significant adverse effect on mean adult emergence and parasitism performance. Ten days might be the optimum cold-storage period at 10°C, as parasitism performance, emergence rate, and progeny production at this storage period were similar to the control of 26°C. Furthermore, the developmental period, emergence rate, and sex ratio of progeny that emerged from cold-stored parasitized pupae were not influenced by storage periods, whereas parasitism performance of progeny decreased as storage period increased. This study suggests that about 24-26°C would be the optimal temperature for mass production and release of T. brontispae for biological control of B. longissima. These results also provide novel findings that a period of 10 d at 10°C may be more suitable and acceptable for ideal cold storage of parasitized pupae of T. brontispae. © The Author 2014. Published by

  4. 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…

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

    NARCIS (Netherlands)

    Bruinsma, M.; IJdema, H.; Loon, van J.J.A.; 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

  6. 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

  7. Extending the Similarity-Attraction Effect : The effects of When-Similarity in mediated communication

    NARCIS (Netherlands)

    Kaptein, M.C.; Castaneda, D.; Fernandez, N.; Nass, C.

    2014-01-01

    The feeling of connectedness experienced in computer-mediated relationships can be explained by the similarity-attraction effect (SAE). Though SAE is well established in psychology, the effects of some types of similarity have not yet been explored. In 2 studies, we demonstrate similarity-attraction

  8. Host niches and defensive extended phenotypes structure parasitoid wasp communities.

    Directory of Open Access Journals (Sweden)

    Richard Bailey

    2009-08-01

    Full Text Available Oak galls are spectacular extended phenotypes of gallwasp genes in host oak tissues and have evolved complex morphologies that serve, in part, to exclude parasitoid natural enemies.Parasitoids and their insect herbivore hosts have coevolved to produce diverse communities comprising about a third of all animal species. The factors structuring these communities, however, remain poorly understood. An emerging theme in community ecology is the need to consider the effects of host traits, shaped by both natural selection and phylogenetic history, on associated communities of natural enemies. Here we examine the impact of host traits and phylogenetic relatedness on 48 ecologically closed and species-rich communities of parasitoids attacking gall-inducing wasps on oaks. Gallwasps induce the development of spectacular and structurally complex galls whose species- and generation-specific morphologies are the extended phenotypes of gallwasp genes. All the associated natural enemies attack their concealed hosts through gall tissues, and several structural gall traits have been shown to enhance defence against parasitoid attack. Here we explore the significance of these and other host traits in predicting variation in parasitoid community structure across gallwasp species. In particular, we test the "Enemy Hypothesis," which predicts that galls with similar morphology will exclude similar sets of parasitoids and therefore have similar parasitoid communities. Having controlled for phylogenetic patterning in host traits and communities, we found significant correlations between parasitoid community structure and several gall structural traits (toughness, hairiness, stickiness, supporting the Enemy Hypothesis. Parasitoid community structure was also consistently predicted by components of the hosts' spatiotemporal niche, particularly host oak taxonomy and gall location (e.g., leaf versus bud versus seed. The combined explanatory power of structural and

  9. Red is Romantic, but Only for Feminine Females: Sexual Dimorphism Moderates Red Effect on Sexual Attraction

    OpenAIRE

    Fangfang Wen; Bin Zuo; Yang Wu; Shan Sun; Ke Liu

    2014-01-01

    Previous researchers have documented that the color red enhances one's sexual attraction to the opposite sex. The current study further examined the moderating role of sexual dimorphism in red effects. The results indicated that red enhanced men's sexual attraction to women with more feminine facial characteristics but had no effect on ratings of perceived general attractiveness. Red clothing also had a marginally significant effect on men's sexual attractiveness. In addition, regardless of s...

  10. Semiochemicals From Fungal Associates of Bark Beetles May Mediate Host Location Behavior of Parasitoids

    Science.gov (United States)

    Brian T. Sullivan; C. Wayne Berisford

    2004-01-01

    In laboratory olfactometer bioassays, females of two hymenopteran parasitoid species, Roptrocerus xylophagorum (Ratzeburg) (Hymenoptera: Pteromalidae) and Spathius pallidus (Ashmead) (Hymenoptera: Braconidae), were attracted to odors from bark or bolts of loblolly pine, Pinus taeda L., colonized by bluestain fungi (genus ...

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

    OpenAIRE

    Jones, A L; Kramer, R.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 ...

  12. Factors affecting stem borer parasitoid species diversity and parasitism in cultivated and natural habitats.

    Science.gov (United States)

    Mailafiya, Duna Madu; Le Ru, Bruno Pierre; Kairu, Eunice Waitherero; Calatayud, Paul-André; Dupas, Stéphane

    2010-02-01

    The effects of biotic and abiotic factors on stem borer parasitoid diversity, abundance, and parasitism were studied in cultivated and natural habitats in four agroecological zones in Kenya. Comparing habitat types, we found partial support for the "natural enemy" hypothesis, whereby, across all localities, parasitoid diversity was higher in more diverse host plant communities in natural habitats, whereas parasitoid abundance was higher in cultivated habitats. For both habitats, parasitoid richness was mainly influenced by stem borer density and/or its interaction with stem borer richness, whereas parasitoid abundance was mainly affected by stem borer abundance. Parasitoid richness was higher in localities (with bimodal rainfall distribution) with increased spatial and temporal availability of host plants that harbored the borers. Across seasons, parasitoid richness was lower in both cultivated and natural habitats in the driest locality, Mtito Andei. Overall, parasitoid diversity was low in Suam and Mtito Andei, where maize cultivation was practiced on a commercial scale and intense grazing activities persist across seasons, respectively. Across localities, habitats, and seasons, stem borer parasitism was positively correlated with parasitoid richness and abundance. Furthermore, the interaction of rainfall and altitude influenced the presence and absence of parasitoids, and consequently, stem borer parasitism. Parasitism was positively and negatively correlated with temperature in cultivated and natural habitats, respectively. Overall, natural habitats seem to serve as important refugia for sustaining parasitoid diversity, which in turn can affect stem borer parasitism in the cereal cropping system.

  13. 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.

  14. Effect of host quality of Callosobruchus maculatus (Coleoptera: Bruchidae) on performance of the egg parasitoid Uscana Iariophaga (Hymenoptera: Trichogrammatidae)

    NARCIS (Netherlands)

    Spitzen, J.; Huis, van A.

    2005-01-01

    Development and reproductive success of the solitary egg parasitoid Uscana lariophaga Steffan were examined after development in eggs of the bruchid storage pest Callosobruchus maculatus Fabricius reared at either low or high densities on cowpea seeds and laid at day 1 and 4 of maternal life. Both

  15. The Effect of Attractiveness on Recognition Memory when Women Look at Female Faces

    OpenAIRE

    Kana Kuraguchi; Hiroshi Ashida

    2011-01-01

    In previous studies, the relationship between facial attractiveness and memory has been inconsistent. We investigated the effect of facial attractiveness on recognition memory in terms of gender and judgment contents. Both female and male facial images were judged for their attractiveness and personal character, and incidental memory was tested later. Recognition performance was shown as d' and analyzed with 2 (participant's gender) x 2 (condition of attractiveness) ANOVA. The interaction was...

  16. The effect of bark thickness on the effectiveness of Tetrastichus planipennisi (Hymen: Eulophidae) and Atanycolus spp. (Hymen: Braconidae), two parasitoids of emerald ash borer (Coleop: Buprestidae)

    Science.gov (United States)

    Kristopher J. Abell; Jian J. Duan; Leah Bauer; Jonathan P. Lelito; Roy G. Van Driesche

    2012-01-01

    Parasitoids have recently been introduced from Asia to aid in biological control in the United States of the invasive, highly damaging, emerald ash borer, Agrilus planipennis. Three introduced parasitoids have established and field biological studies are underway to improve our understanding of niche partitioning among them. Here we report one such...

  17. Potential Side Effects of the Entomopathogenic Fungus Metarhizium anisopliae on the Egg Parasitoid Trichogramma pretiosum (Hymenoptera: Trichogrammatidae) Under Controlled Conditions.

    Science.gov (United States)

    Potrich, M; Alves, L F A; Lozano, E R; Bonini, A K; Neves, P M O J

    2017-10-06

    The purpose was to evaluate the side effects of strains Metarhizium anisopliae (Metsch.) Sorokin sensu lato Unioeste 43 and M. anisopliae sensu stricto ESALQ 1641 on Trichogramma pretiosum Riley (Hymenoptera: Trichogrammatidae) under controlled conditions. A free-choice test for parasitism was performed, with the confinement of T. pretiosum females mated with cards (1 × 5 cm) containing age-standardized Anagasta kuehniella Zeller eggs, either sprayed with a fungal strain (109 conidia/ml) or 0.01% v/v Tween 80 (control). For the no-choice tests, T. pretiosum females mated were confined with cards sprayed with fungal strains before or after parasitism, and cards with fungal applications at different times. The number of parasitized eggs, percentage of emergence, longevity, egg-to-adult period, sex ratio, total and confirmed mortality by the fungus, and longevity of females that parasitized previously sprayed eggs, were assessed. Histological analysis of immature phases was also performed. The fungus was repellent to T. pretiosum in the free-choice test, while in the no-choice test, fungal applications before and after parasitism did not affect the number of eggs parasitized by T. pretiosum or the sex ratio of emerging adults. However, both strains affected adult emergence rates, the egg-to-adult period, and longevity. Overall, both M. anisopliae strains had minor effects on these biological parameters of T. pretiosum under controlled conditions. Hyphae were not detected in histological observations of immature stages of the parasitoid. © The Authors 2017. Published by Oxford University Press on behalf of Entomological Society of America. All rights reserved. For permissions, please email: journals.permissions@oup.com.

  18. Visibility and anonymity effects on attraction and group cohesiveness

    NARCIS (Netherlands)

    Lea, Martin; Spears, Russell; Watt, Susan E.

    2007-01-01

    This study investigated attraction and group cohesiveness under different visibility and anonymity conditions for social categories that differed in their capacity to be visually cued. Using computer-mediated communication in 36 mixed gender (visually cued category) and nationality (non-visually

  19. Effects of perceived attractiveness and academic success on early adolescent peer popularity.

    Science.gov (United States)

    Boyatzis, C J; Baloff, P; Durieux, C

    1998-09-01

    Effects of perceived attractiveness and academic performance on 9th graders' ratings of peers' popularity were investigated. Participants were 270 9th graders (152 girls, 118 boys) who read a vignette describing a hypothetical same-sex peer with whom the student had been assigned to complete a project. The partner's attractiveness and academic performance were systematically varied in four conditions: high attractiveness/high grades, high attractiveness/low grades, low attractiveness/high grades, and low attractiveness/low grades. After reading the vignette, the students rated the partner's popularity. As hypothesized, analyses of variance revealed that attractive partners were significantly more popular than unattractive partners, regardless of whether the partner had high or low grades. Contrary to expectation, attractiveness was not more important to girls than to boys. Integration with past research and suggestions for future research are offered.

  20. 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.

  1. Malathion-induced oxidative stress in a parasitoid wasp: effect on adult emergence, longevity, fecundity, and oxidative and antioxidative response of Pimpla turionellae (Hymenoptera: Ichneumonidae).

    Science.gov (United States)

    Büyükgüzel, Kemal

    2006-08-01

    Effects of an organophosphorus insecticide, malathion, on survivorship and lipid peroxidation of the greater wax moth, Galleria mellonella (L.), pupae were investigated by rearing the newly hatched larvae on an artificial diet containing 0.01, 0.1, 1, 10, and 100 ppm of the insecticide. As bioindicators of long-term physiological stress responses, the adult emergence rate, longevity, and fecundity associated with lipid peroxidation level and antioxidant enzyme activity in the endoparasitoid Pimpla turionellae (L.) (Hymenoptera: Ichneumonidae) were determined by rearing the parasitoid on a factitious host, G. mellonella pupae treated with malathion. At 100 ppm, malathion significantly decreased pupation rate of G. mellonella larvae and the rate of adult emergence of the parasitoid from these pupae. This concentration resulted in a significant increase in the lipid peroxidation product malondialdehyde (MDA) in both the host and the parasitoid. Malathion at 1 and 10 ppm significantly increased pupation rate and lipid peroxidation level of G. mellonella pupae. The adult emergence rate of P. turionellae was significantly decreased from 63.7 to 20% by these concentrations, whereas MDA content was increased by two- and three-fold, respectively, compared with the control (45.3 +/- 3.2 nmol/ g protein). The longevity of adults was significantly extended from 52.5 +/- 5.7 to 75.7 +/- 6.3 d when the parasitoids emerged from host pupae exposed with 0.1 ppm malathion. At low concentrations (0.01 and 0.1 ppm), malathion significantly increased the number of eggs laid per female per day. However, the lowest concentration (0.01 ppm) had no significant effect on hatchability, whereas 0.1 ppm of the insecticide resulted in significant decrease in egg hatch compared with the control. A significant increase in total superoxide dismutase (SOD) activity for low concentrations of malathion (0.01-1 ppm) was found compared with the control. There was a significant positive correlation of

  2. 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.

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

    Science.gov (United States)

    Zamek, Ashley L; Spinner, Jennifer E; Micallef, Jessica L; Gurr, Geoff M; Reynolds, Olivia L

    2012-10-22

    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.

  4. Red is Romantic, but Only for Feminine Females: Sexual Dimorphism Moderates Red Effect on Sexual Attraction

    Directory of Open Access Journals (Sweden)

    Fangfang Wen

    2014-10-01

    Full Text Available Previous researchers have documented that the color red enhances one's sexual attraction to the opposite sex. The current study further examined the moderating role of sexual dimorphism in red effects. The results indicated that red enhanced men's sexual attraction to women with more feminine facial characteristics but had no effect on ratings of perceived general attractiveness. Red clothing also had a marginally significant effect on men's sexual attractiveness. In addition, regardless of sexual dimorphism cues, male participants rated women with red as warmer and more competent. The underlying mechanisms of the red effect, the limitations of the current study, and suggestions for future directions are discussed.

  5. Red is romantic, but only for feminine females: sexual dimorphism moderates red effect on sexual attraction.

    Science.gov (United States)

    Wen, Fangfang; Zuo, Bin; Wu, Yang; Sun, Shan; Liu, Ke

    2014-08-08

    Previous researchers have documented that the color red enhances one's sexual attraction to the opposite sex. The current study further examined the moderating role of sexual dimorphism in red effects. The results indicated that red enhanced men's sexual attraction to women with more feminine facial characteristics but had no effect on ratings of perceived general attractiveness. Red clothing also had a marginally significant effect on men's sexual attractiveness. In addition, regardless of sexual dimorphism cues, male participants rated women with red as warmer and more competent. The underlying mechanisms of the red effect, the limitations of the current study, and suggestions for future directions are discussed.

  6. Nitrogen and water inputs to tomato plant do not trigger bottom-up effects on a leafminer parasitoid through host and non-host exposures.

    Science.gov (United States)

    Dong, Yong-Cheng; Han, Peng; Niu, Chang-Ying; Zappalà, Lucia; Amiens-Desneux, Edwige; Bearez, Philippe; Lavoir, Anne-Violette; Biondi, Antonio; Desneux, Nicolas

    2017-10-02

    Bottom-up and top-down forces are major components of biological control against pests in an agro-ecosystem. Understanding the multi-trophic interactions between plants and secondary consumers would help optimize pest control strategies. We manipulated nitrogen and/or water inputs to tomato plants (Solanum lycopersicum) to test whether these manipulations could trigger bottom-up effects on the parasitoid Necremnus tutae via host (Tuta absoluta) and/or non-host (Bemisia tabaci) exposures, and compared the control efficacy of N. tutae on T. absoluta in the presence and absence of B. tabaci. The results showed no cascading effects of plant nitrogen and/or water inputs on N. tutae via either host or non-host exposure. The bottom-up force was mitigated by chewing or sap-feeding insect consumers at the second energy level. By contrast, the top-down force on T. absoluta from parasitoids was enhanced by an additionally provided non-host, which could produce alternative food sources extending N. tutae longevity and enhancing the fitness of its offspring. Our results provided evidence for the combination of bottom-up and top-down approaches in tomato integrated pest management programs. © 2017 Society of Chemical Industry. © 2017 Society of Chemical Industry.

  7. Effects of Entomopathogenic Nematodes on the Development of Root-knot Nematode and Aphid, and on the Parasitism of Aphid Parasitoid in Tobacco

    Directory of Open Access Journals (Sweden)

    WANG Yu-kun

    2017-05-01

    Full Text Available Entomopathogenic nematodes(EPN which is recognized as a kind of potential biological control material have been paid more and more attention in recent years. In the present study, we selected tobacco(Nicotiana tabacum as the object to study the effects of EPN (Steinernema carpocapsae and Heterorhabditis bacteriophoraon the development of root-knot nematodes and aphid (Myzus persicae, and on the parasitism of aphid parasitoid (Aphidius gifuensis in tobacco. The results showed that (1Under the condition of the artificial removal of aphids, the number of egg per plant was significantly lower under the EPN treatments than control treatment(PS. carpocapsae treatment than the other treatments(PH. bacteriophora cadaver treatment were 89.6 individual·plant-1 and 0.996 g·plant-1, 99.8 individual·plant-1 and 3.258 g·plant-1, 76.6 individual·plant-1 and 1.643 g·plant-1, respectively, indicating that EPN treatment could decrease the number of aphids per mass; (3On the first three observation dates, the number of aphid mummies was significantly lower under S. carpocapsae cadaver treatment than H. bacteriophora cadaver treatment. The results indicated that EPN treatments in tobacco could affect the development of root-knot nematode, and had impact on the development of aphids and the activities of aphid parasitoid by "bottom-up" approach, and these effects were affected by the species of EPN.

  8. 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

  9. Response of the braconid parasitoid Cotesia (= Apanteles) glomerata to volatile infochemicals: effects of bioassay set-up, parasitoid age and experience and barometric flux.

    NARCIS (Netherlands)

    Steinberg, S.; Dicke, M.; Vet, L.E.M.; Wanningen, R.

    1992-01-01

    Upon initiating a research project on the role of volatile infochemicals in the tritrophic system Cotesia (= Apanteles) glomerata (L.)-Pieris brassicae (L.)-cabbage, a bioassay was developed to investigate the response of C. glomerata. The bioassay should be effective in terms of high responsiveness

  10. Facial Cosmetics and Attractiveness: Comparing the Effect Sizes of Professionally-Applied Cosmetics and Identity.

    Science.gov (United States)

    Jones, Alex L; Kramer, Robin S S

    2016-01-01

    Forms of body decoration exist in all human cultures. However, in Western societies, women are more likely to engage in appearance modification, especially through the use of facial cosmetics. How effective are cosmetics at altering attractiveness? Previous research has hinted that the effect is not large, especially when compared to the variation in attractiveness observed between individuals due to differences in identity. In order to build a fuller understanding of how cosmetics and identity affect attractiveness, here we examine how professionally-applied cosmetics alter attractiveness and compare this effect with the variation in attractiveness observed between individuals. In Study 1, 33 YouTube models were rated for attractiveness before and after the application of professionally-applied cosmetics. Cosmetics explained a larger proportion of the variation in attractiveness compared with previous studies, but this effect remained smaller than variation caused by differences in attractiveness between individuals. Study 2 replicated the results of the first study with a sample of 45 supermodels, with the aim of examining the effect of cosmetics in a sample of faces with low variation in attractiveness between individuals. While the effect size of cosmetics was generally large, between-person variability due to identity remained larger. Both studies also found interactions between cosmetics and identity-more attractive models received smaller increases when cosmetics were worn. Overall, we show that professionally-applied cosmetics produce a larger effect than self-applied cosmetics, an important theoretical consideration for the field. However, the effect of individual differences in facial appearance is ultimately more important in perceptions of attractiveness.

  11. Side-effects of cowpea treatment with botanical insecticides on two parasitoids of Callosobruchus maculatus

    NARCIS (Netherlands)

    Boeke, S.J.; Sinzogan, A.A.C.; Almeida, de R.P.; Boer, de P.W.M.; Jeong, G.S.; Kossou, D.K.; Loon, van J.J.A.

    2003-01-01

    Studies on the protective effect of botanical products against pest insects have infrequently been extended to side-effects on natural enemies. Indirect effects of botanicals on the storability of seeds could occur through their possible negative impact on biological control agents. Four plant

  12. The Effect of Attractiveness on Recognition Memory when Women Look at Female Faces

    Science.gov (United States)

    Kuraguchi, Kana; Ashida, Hiroshi

    2011-01-01

    In previous studies, the relationship between facial attractiveness and memory has been inconsistent. We investigated the effect of facial attractiveness on recognition memory in terms of gender and judgment contents. Both female and male facial images were judged for their attractiveness and personal character, and incidental memory was tested later. Recognition performance was shown as d' and analyzed with 2 (participant's gender) x 2 (condition of attractiveness) ANOVA. The interaction was significant for female faces but not for male faces. It is, therefore, suggested that the difference of gender affects the recognition memory concerning facial attractiveness. In particular, attractiveness of female faces had different effects for female participants when compared to other combinations. As a control, the interaction for female faces was not significant when the task was to judge the physical features such as the size of eyes and the angle of mouth. In sum, unattractive faces were better recognized than attractive faces in general except for the case when women judged attractiveness of female faces. These results suggest that there may be an effect of attention to attractiveness on recognition memory that is particularly strong when women look at female faces.

  13. The Effect of Attractiveness on Recognition Memory when Women Look at Female Faces

    Directory of Open Access Journals (Sweden)

    Kana Kuraguchi

    2011-05-01

    Full Text Available In previous studies, the relationship between facial attractiveness and memory has been inconsistent. We investigated the effect of facial attractiveness on recognition memory in terms of gender and judgment contents. Both female and male facial images were judged for their attractiveness and personal character, and incidental memory was tested later. Recognition performance was shown as d' and analyzed with 2 (participant's gender x 2 (condition of attractiveness ANOVA. The interaction was significant for female faces but not for male faces. It is, therefore, suggested that the difference of gender affects the recognition memory concerning facial attractiveness. In particular, attractiveness of female faces had different effects for female participants when compared to other combinations. As a control, the interaction for female faces was not significant when the task was to judge the physical features such as the size of eyes and the angle of mouth. In sum, unattractive faces were better recognized than attractive faces in general except for the case when women judged attractiveness of female faces. These results suggest that there may be an effect of attention to attractiveness on recognition memory that is particularly strong when women look at female faces.

  14. 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.

  15. 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

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

    OpenAIRE

    Zamek, Ashley L.; Spinner, Jennifer E.; Micallef, Jessica L.; Gurr, Geoff M.; Reynolds, Olivia L.

    2012-01-01

    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...

  17. Genetic engineering of plant volatile terpenoids: effects on a herbivore, a predator and a parasitoid

    NARCIS (Netherlands)

    Kos, M.; Houshyani, B.; Overeem, A.J.; Bouwmeester, H.J.; Weldegergis, B.T.; van Loon, J.J.A.; Dicke, M.; Vet, L.E.M.

    2013-01-01

    BACKGROUND: Most insect-resistant transgenic crops employ toxins to control pests. A novel approach is to enhance the effectiveness of natural enemies by genetic engineering of the biosynthesis of volatile organic compounds (VOCs). Before the commercialisation of such transgenic plants can be

  18. 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.

  19. 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…

  20. An effective attractive electron-electron interaction and high-Tc superconductivity

    Energy Technology Data Exchange (ETDEWEB)

    Howson, M.A.; Porter, J.; Morgan, G.J. (Dept. of Physics, Univ. of Leeds (UK))

    1991-01-15

    The repulsive Coulomb interaction is usually seen as opposing the attractive phonon mediated interaction giving rise to superconductivity. Here we show how the vertex part for electron-electron scattering can lead to an effective attractive Coulomb interaction. We then solve the Eliashberg equations with this effective vertex correction and calculate Tc for a model density of states as we vary the strength of the interaction and the effective mass of the electrons. (orig.).

  1. 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...

  2. Effects of symmetry and familiarity on the attractiveness of human faces

    Directory of Open Access Journals (Sweden)

    Mentus Tatjana

    2016-01-01

    Full Text Available The effects of both symmetry (perceptual factor and familiarity (cognitive factor on facial attractiveness were investigated. From the photographs of original slightly asymmetric faces, symmetric left-left (LL and right-right (RR versions were generated. Familiarity was induced in the learning block using the repetitive presentation of original faces. In the test block participants rated the attractiveness of original, previously seen (familiar faces, original, not previously seen faces, and both LL and RR versions of all faces. The analysis of variance showed main effects of symmetry. Post hoc tests revealed that asymmetric original faces were rated as more attractive than both LL and RR symmetric versions. Familiarity doesn’t have a significant main effect, but the symmetry-familiarity interaction was obtained. Additional post hoc tests indicated that facial attractiveness is positively associated with natural slight asymmetry rather than with perfect symmetry. Also, unfamiliar LL symmetric versions were rated as more attractive than familiar LL versions, whereas familiar RR versions were rated as more attractive than RR unfamiliar faces. These results suggested that symmetry (perceptual factor and familiarity (cognitive or memorial factor play differential roles in facial attractiveness, and indicate a relatively stronger effect of the perceptual compared to the cognitive factor. [Projekat Ministarstva nauke Republike Srbije, br. ON179018 i br. ON179033

  3. The Effect of Organizational Attraction and Corporate Reputation on Applicants’ Intention to Join Organization

    Directory of Open Access Journals (Sweden)

    Murat Güler

    2015-10-01

    Full Text Available The purpose of this study was to investigate generalizability of the effect of organizational attraction and corporate reputation on applicants’ intention to join an organization in Turkish sample. The data were collected from 539 students who applied to join a public high education institution. The research hypotheses were tested with correlation and regression analyzes. The applicants' attitudes toward attractiveness of the organization and corporate reputation, which reflects the collective assessment of community about organization, have been identified as significant predictors of applicants' intention to join the organization. Also, it was identified that the effect of corporate reputation on applicants' intention to join the organization was partially mediated by organizational attraction..

  4. Effects of Direct Experience and Vicarious Experience on Group Therapeutic Attraction

    Science.gov (United States)

    Silver, Robert J.; Conyne, Robert K.

    1977-01-01

    Tests the hypothesis that if direct small group experience was shown to be relatively more effective than vicarious experience in heightening attraction, then a significant assumption of T-group theory would receive support. Results support the hypothesis. (Author)

  5. On the Nature of Clitics and Their Sensitivity to Number Attraction Effects

    National Research Council Canada - National Science Library

    Mikel Santesteban; Adam Zawiszewski; Kepa Erdocia; Itziar Laka

    2017-01-01

    .... In Experiment 1, an acceptability judgment self-paced reading task was used. Accuracy data yielded reliable attraction effects in both grammatical and ungrammatical sentences, only in singular (but not plural) clitics...

  6. Facial cosmetics and attractiveness: comparing the effect sizes of professionally-applied cosmetics and identity

    OpenAIRE

    Jones, Alex L.; Robin S S Kramer

    2016-01-01

    Forms of body decoration exist in all human cultures. However, in Western societies, women are more likely to engage in appearance modification, especially through the use of facial cosmetics. How effective are cosmetics at altering attractiveness? Previous research has hinted that the effect is not large, especially when compared to the variation in attractiveness observed between individuals due to differences in identity. In order to build a fuller understanding of how cosmetics and identi...

  7. Facial Cosmetics and Attractiveness: Comparing the Effect Sizes of Professionally-Applied Cosmetics and Identity

    OpenAIRE

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

    2016-01-01

    Forms of body decoration exist in all human cultures. However, in Western societies, women are more likely to engage in appearance modification, especially through the use of facial cosmetics. How effective are cosmetics at altering attractiveness? Previous research has hinted that the effect is not large, especially when compared to the variation in attractiveness observed between individuals due to differences in identity. In order to build a fuller understanding of how cosmetics and identi...

  8. On the Nature of Clitics and Their Sensitivity to Number Attraction Effects

    OpenAIRE

    Mikel Santesteban; Adam Zawiszewski; Kepa Erdocia; Itziar Laka

    2017-01-01

    Pronominal dependencies have been shown to be more resilient to attraction effects than subject-verb agreement. We use this phenomenon to investigate whether antecedent-clitic dependencies in Spanish are computed like agreement or like pronominal dependencies. In Experiment 1, an acceptability judgment self-paced reading task was used. Accuracy data yielded reliable attraction effects in both grammatical and ungrammatical sentences, only in singular (but not plural) clitics. Reading times did...

  9. On the Nature of Clitics and Their Sensitivity to Number Attraction Effects

    Directory of Open Access Journals (Sweden)

    Mikel Santesteban

    2017-09-01

    Full Text Available Pronominal dependencies have been shown to be more resilient to attraction effects than subject-verb agreement. We use this phenomenon to investigate whether antecedent-clitic dependencies in Spanish are computed like agreement or like pronominal dependencies. In Experiment 1, an acceptability judgment self-paced reading task was used. Accuracy data yielded reliable attraction effects in both grammatical and ungrammatical sentences, only in singular (but not plural clitics. Reading times did not show reliable attraction effects. In Experiment 2, we measured electrophysiological responses to violations, which elicited a biphasic frontal negativity-P600 pattern. Number attraction modulated the frontal negativity but not the amplitude of the P600 component. This differs from ERP findings on subject-verb agreement, since when the baseline matching condition obtained a biphasic pattern, attraction effects only modulated the P600, not the preceding negativity. We argue that these findings support cue-retrieval accounts of dependency resolution and further suggest that the sensitivity to attraction effects shown by clitics resembles more the computation of pronominal dependencies than that of agreement.

  10. On the Nature of Clitics and Their Sensitivity to Number Attraction Effects.

    Science.gov (United States)

    Santesteban, Mikel; Zawiszewski, Adam; Erdocia, Kepa; Laka, Itziar

    2017-01-01

    Pronominal dependencies have been shown to be more resilient to attraction effects than subject-verb agreement. We use this phenomenon to investigate whether antecedent-clitic dependencies in Spanish are computed like agreement or like pronominal dependencies. In Experiment 1, an acceptability judgment self-paced reading task was used. Accuracy data yielded reliable attraction effects in both grammatical and ungrammatical sentences, only in singular (but not plural) clitics. Reading times did not show reliable attraction effects. In Experiment 2, we measured electrophysiological responses to violations, which elicited a biphasic frontal negativity-P600 pattern. Number attraction modulated the frontal negativity but not the amplitude of the P600 component. This differs from ERP findings on subject-verb agreement, since when the baseline matching condition obtained a biphasic pattern, attraction effects only modulated the P600, not the preceding negativity. We argue that these findings support cue-retrieval accounts of dependency resolution and further suggest that the sensitivity to attraction effects shown by clitics resembles more the computation of pronominal dependencies than that of agreement.

  11. 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.

  12. An improved culturing method for opiine fruit fly parasitoids and its application to parasitoid monitoring in the field.

    Science.gov (United States)

    Masry, Ayad; Furlong, Michael J; Clarke, Anthony R; Cunningham, John Paul

    2018-02-01

    Good culturing methods play an important role in the study of insect behavior and its application to pest management. Here, we describe and validate a new method for rearing the parasitoid wasp, Diachasmimorpha kraussii, which attacks some of the world's worst fruit fly pests and is an internationally used biological control agent. Our method differs from standard culturing approaches by presenting adult wasps with host-infested artificial media within a "culturing bag," which mimics a natural (fruit) oviposition substrate. In laboratory trials using wild collected D. kraussii, the culturing bag method was compared to the use of host-infested nectarines, and a commonly used laboratory method of presenting host-infested artificial media within Petri dishes. The culturing bag method proved to be a significant improvement on both methods, combining the advantages of high host survival in artificial media with parasitism levels that were the equivalent to those recorded using host-infested fruits. In our field study, culturing bags infested with the Queensland fruit fly, Bactrocera tryoni, and hung in a mixed peach and nectarine orchard proved to be effective "artificial fruits" attracting wild D. kraussii for oviposition. Significantly more adult wasps were reared from the culturing bags compared to field collected fruits. This was shown to be due to higher fruit fly larval density in the bags, as similar percentage parasitism rates were found between the culturing bags and ripe fruits. We discuss how this cheap, time-efficient method could be applied to collecting and monitoring wild D. kraussii populations in orchards, and assist in maintaining genetic variability in parasitoid laboratory cultures. © 2016 Institute of Zoology, Chinese Academy of Sciences.

  13. Visual exposure to obesity: Experimental effects on attraction toward overweight men and mate choice in females.

    Science.gov (United States)

    Robinson, E; Christiansen, P

    2015-09-01

    Cultural differences in ideal body weight are well established, but less research has examined attraction toward potential mates of heavier body weights. We examined whether exposure to obesity increases physical attraction toward overweight men. In Studies 1 and 2, we examined the effect that exposure to obese vs healthy weight men had on female attraction toward an overweight man. Study 3 examined whether females who are regularly exposed to males of heavier body weights reported a greater attraction toward overweight men. Study 4 tested whether females in an online dating study were more likely to choose to date an overweight man, after having been exposed to obesity. Exposure to obesity altered visual perceptions of what normal and therefore healthy body weights were and this resulted in greater attraction toward an overweight man (Studies 1 and 2). Females regularly exposed to men of heavier body weight reported a greater attraction toward overweight men (Study 3). After exposure to obesity, females in an online dating study were more likely to choose to date an overweight man ahead of a healthy weight man (Study 4). Exposure to male obesity increases female attraction toward overweight men and may affect mate choice.

  14. Age-Differential Effects of Job Characteristics on Job Attraction: A Policy-Capturing Study

    OpenAIRE

    Hannes Zacher; Dirkers, Bodil T.; Sabine Korek; Brenda Hughes

    2017-01-01

    Based on an integration of job design and lifespan developmental theories, Truxillo et al. (2012) proposed that job characteristics interact with employee age in predicting important work outcomes. Using an experimental policy-capturing design, we investigated age-differential effects of four core job characteristics (i.e., job autonomy, task variety, task significance, and feedback from the job) on job attraction (i.e., individuals' rating of job attractiveness). Eighty-two employees between...

  15. Systemic Imidacloprid Affects Intraguild Parasitoids Differently.

    Directory of Open Access Journals (Sweden)

    Sally V Taylor

    Full Text Available 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.

  16. Systemic Imidacloprid Affects Intraguild Parasitoids Differently

    Science.gov (United States)

    Roe, R. Michael; Bacheler, Jack S.

    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

  17. Deforestation homogenizes tropical parasitoid-host networks.

    Science.gov (United States)

    Laliberté, Etienne; Tylianakis, Jason M

    2010-06-01

    Human activities drive biotic homogenization (loss of regional diversity) of many taxa. However, whether species interaction networks (e.g., food webs) can also become homogenized remains largely unexplored. Using 48 quantitative parasitoid-host networks replicated through space and time across five tropical habitats, we show that deforestation greatly homogenized network structure at a regional level, such that interaction composition became more similar across rice and pasture sites compared with forested habitats. This was not simply caused by altered consumer and resource community composition, but was associated with altered consumer foraging success, such that parasitoids were more likely to locate their hosts in deforested habitats. Furthermore, deforestation indirectly homogenized networks in time through altered mean consumer and prey body size, which decreased in deforested habitats. Similar patterns were obtained with binary networks, suggesting that interaction (link) presence-absence data may be sufficient to detect network homogenization effects. Our results show that tropical agroforestry systems can support regionally diverse parasitoid-host networks, but that removal of canopy cover greatly homogenizes the structure of these networks in space, and to a lesser degree in time. Spatiotemporal homogenization of interaction networks may alter coevolutionary outcomes and reduce ecological resilience at regional scales, but may not necessarily be predictable from community changes observed within individual trophic levels.

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

    Directory of Open Access Journals (Sweden)

    Jianing Wei

    2007-09-01

    Full Text Available 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.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.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 used to improve the precision of the host location by the parasitoids.

  19. Effects of Objective 3-Dimensional Measures of Facial Shape and Symmetry on Perceptions of Facial Attractiveness.

    Science.gov (United States)

    Hatch, Cory D; Wehby, George L; Nidey, Nichole L; Moreno Uribe, Lina M

    2017-09-01

    Meeting patient desires for enhanced facial esthetics requires that providers have standardized and objective methods to measure esthetics. The authors evaluated the effects of objective 3-dimensional (3D) facial shape and asymmetry measurements derived from 3D facial images on perceptions of facial attractiveness. The 3D facial images of 313 adults in Iowa were digitized with 32 landmarks, and objective 3D facial measurements capturing symmetric and asymmetric components of shape variation, centroid size, and fluctuating asymmetry were obtained from the 3D coordinate data using geo-morphometric analyses. Frontal and profile images of study participants were rated for facial attractiveness by 10 volunteers (5 women and 5 men) on a 5-point Likert scale and a visual analog scale. Multivariate regression was used to identify the effects of the objective 3D facial measurements on attractiveness ratings. Several objective 3D facial measurements had marked effects on attractiveness ratings. Shorter facial heights with protrusive chins, midface retrusion, faces with protrusive noses and thin lips, flat mandibular planes with deep labiomental folds, any cants of the lip commissures and floor of the nose, larger faces overall, and increased fluctuating asymmetry were rated as significantly (P attractive. Perceptions of facial attractiveness can be explained by specific 3D measurements of facial shapes and fluctuating asymmetry, which have important implications for clinical practice and research. Copyright © 2017 American Association of Oral and Maxillofacial Surgeons. Published by Elsevier Inc. All rights reserved.

  20. 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

  1. Manipulation of parasitoids for aphid pest management: progress and prospects.

    Science.gov (United States)

    Powell, Wilf; Pickett, John A

    2003-02-01

    This paper describes research at IACR-Rothamsted on aphid parasitoid responses to semiochemical foraging stimuli, aimed at developing novel ways of manipulating these behaviours to overcome ecological constraints to biological and integrated pest control. Female parasitoids respond both to aphid sex pheromones acting as kairomones, and to aphid-induced plant volatiles, acting as synomones. A range of economically important parasitoid species respond to aphid sex pheromones, and their potential for enhancing parasitization of aphid populations has been demonstrated in the field. Commercial production of the pheromone from the plant Nepeta cataria L has been developed and strategies for its use in arable crops are being investigated. Aphid-induced plant volatiles are released systemically throughout the plant and are aphid species specific, probably induced by elicitors in aphid saliva. Aphid-infested plants can induce uninfested neighbours to release damage-related volatiles, plant-to-plant communication occurring via the rhizosphere. The plant compound cis-jasmone has been identified as a plant signal with potential for aphid control, inducing plant defence mechanisms that both deter colonising aphids and attract parasitoids and predators. Such compounds may represent a new generation of crop protectants and their further investigation and development will be aided by the tools generated by genomic and post-genomic biology.

  2. 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

  3. Extending the Similarity-Attraction Effect: The Effects of When-Similarity in Computer-Mediated Communication

    NARCIS (Netherlands)

    Kaptein, M.C.; Castaneda, D.; Fernandez, N.; Nass, C.

    2014-01-01

    The feeling of connectedness experienced in computer-mediated relationships can be explained by the similarity-attraction effect (SAE). Though SAE is well established in psychology, the effects of some types of similarity have not yet been explored. In 2 studies, we demonstrate similarity-attraction

  4. Parasitoid wasps indirectly suppress seed production by stimulating consumption rates of their seed-feeding hosts.

    Science.gov (United States)

    Xi, Xinqiang; Eisenhauer, Nico; Sun, Shucun

    2015-07-01

    In parasitoid-herbivore-plant food chains, parasitoids may be simultaneously linked with both herbivore hosts and plants, as occurs when herbivores attacked by parasitoids continue to consume plants although they are destined to die. This peculiar property may cause parasitoids to confer a differential trophic cascading effect on plants than that known for typical predators. We hypothesized that larval koinobiont parasitoids would confer an immediate negative effect on plant seed production by stimulating consumption of their seed-predator hosts. We tested this hypothesis in an alpine parasitic food chain of plant seeds, pre-dispersal seed predators (tephritid fly larvae) and koinobiont parasitoids using field observations, a field experiment and a microcosm study. We first compared observed seed production in (i) non-infected capitula, (ii) capitula infected only by seed predators (tephritid flies) and (iii) capitula infected by both seed predators and their parasitoids in five Asteraceae species. Consistent with our hypothesis, seed loss in the capitula with both seed predators and parasitoids was significantly greater than in the capitula infested only by seed predators. This effect was replicated in a controlled field experiment focusing on the most common parasitoid-seed predator-plant interaction chain in our system, in which confounding factors (e.g. density and phenology) were excluded. Here, we show that parasitoids indirectly decreased plant seed production by changing the behaviour of seed predators. In a microcosm study, we show that larval parasitoids significantly extended the growth period and increased the terminal size of their host tephritid maggots. Thus, parasitoids suppressed plant seed production by stimulating the growth and consumption of the fly maggots. In contrast to the typical predator-induced trophic cascade, we highlight the significance of parasitoids indirectly decreasing plant fitness by stimulating consumption by seed predators

  5. Effect of smile index and incisal edge position on perception of attractiveness in different age groups.

    Science.gov (United States)

    Chou, J-C; Nelson, A; Katwal, D; Elathamna, E N; Durski, M T

    2016-11-01

    Changes in occlusal vertical dimension (OVD) and age have been found to affect Smile Index (SI, width/height of smile). Limited information is available regarding the aesthetic effects of these changes. The objective of this study was to evaluate the attractiveness of digitally manipulated smile images with differences in SI and incisal edge position (IEP) judged by respondents in different age groups. A total of 12 smile images were generated with varying SI (3·5, 5·3, 7·2, 9·0) and IEP (High, Medium, Low). Fifty respondents each in four age groups (15-24, 25-39, 40-54, 55+) evaluated the attractiveness of the 12 images using a 0-10 visual analog scale (VAS, 10 being most attractive). A repeated-measures three-factorial mixed model assessed differences. SI, IEP and age of respondents were found to significantly influence attractiveness score (P age groups combined, SI = 7·2/IEP = Medium was most attractive (VAS = 7·22), followed by SI = 9·0/IEP = Medium, and SI = 5·3/IEP = Medium (VAS = 6·53 and 6·48, respectively). SI = 3·5/IEP = High and SI = 3·5/IEP = Low were least attractive (VAS = 1·99 and VAS = 2·58, respectively). Age group significantly influenced aesthetic perception, with younger respondents more critical in differences in SI and IEP. SI and IEP significantly influenced attractiveness of the smile in all respondent age groups. Low SI (i.e. 3·5) combined with high or low IEP was unattractive. Medium SI to high SI (i.e. 5·3-9·0) combined with medium IEP were considered attractive. © 2016 John Wiley & Sons Ltd.

  6. Parasitoids of the Southern Pine Beetle

    Science.gov (United States)

    C. Wayne Berisford

    2011-01-01

    Hymenopterous parasitoids make up a significant portion of the natural enemy complex associated with the southern pine beetle (SPB). Collectively, parasitoids can affect the growth of individual SPB infestations and area populations by reducing the survival rates of developing SPB larval/pupal broods. A substantial body of information on parasitoids has been...

  7. The effects of objectification on stereotypical perception and attractiveness of women and men

    Directory of Open Access Journals (Sweden)

    Rollero Chiara

    2016-01-01

    Full Text Available Objectification has been found to have negative consequences on how women are perceived by others. However in an even more sexualized world being a sexual object has become a standard of physical attractiveness for women and objectification could foster a positive evaluation increasing attractiveness. Although Objectification Theory was originally grounded in women’s experiences, some research points to the promise of Objectification Theory for understanding men’s experiences as well. The aim of the paper was investigating the effects of objectification on gender stereotypes and perceived attractiveness. Two experimental studies were conducted. Study 1 (N=139 investigated the effects of objectification on female targets. Study 2 (N=146 investigated the effects on male targets. In both studies three dependent variables were considered: communality, agency, and attractiveness. Results of Study 1 revealed that objectified women were considered less communal and more attractive. Moreover, men perceived objectified women less agentic than the non-objectified ones, whereas women showed the opposite perception. Concerning men, objectification has a limited impact, as it interacted with participants’ gender only on communality: men considered objectified males more communal than the non-objectified ones, while women revealed the opposite perception.

  8. The Effectiveness of Engineering Workshops in Attracting Females into Engineering Fields: A Review of the Literature

    Science.gov (United States)

    Sinkele, Carrie Nicole; Mupinga, Davison M.

    2011-01-01

    All-girl engineering workshops are increasing in popularity as a means to attract females into the male-dominated field of engineering. However, the effectiveness of such workshops as a recruitment tool is unclear. This report summarizes several research studies on this topic with the intent of showing the effectiveness of such workshops and other…

  9. 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)

  10. Molecular Theory and the Effects of Solute Attractive Forces on Hydrophobic Interactions.

    Science.gov (United States)

    Chaudhari, Mangesh I; Rempe, Susan B; Asthagiri, D; Tan, L; Pratt, L R

    2016-03-03

    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. 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.

  11. Attractive celebrity and peer images on Instagram: Effect on women's mood and body image.

    Science.gov (United States)

    Brown, Zoe; Tiggemann, Marika

    2016-12-01

    A large body of research has documented that exposure to images of thin fashion models contributes to women's body dissatisfaction. The present study aimed to experimentally investigate the impact of attractive celebrity and peer images on women's body image. Participants were 138 female undergraduate students who were randomly assigned to view either a set of celebrity images, a set of equally attractive unknown peer images, or a control set of travel images. All images were sourced from public Instagram profiles. Results showed that exposure to celebrity and peer images increased negative mood and body dissatisfaction relative to travel images, with no significant difference between celebrity and peer images. This effect was mediated by state appearance comparison. In addition, celebrity worship moderated an increased effect of celebrity images on body dissatisfaction. It was concluded that exposure to attractive celebrity and peer images can be detrimental to women's body image. Copyright © 2016 Elsevier Ltd. All rights reserved.

  12. 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.

  13. Combined use of herbivore-induced plant volatiles and sex pheromones for mate location in braconid parasitoids.

    Science.gov (United States)

    Xu, Hao; Desurmont, Gaylord; Degen, Thomas; Zhou, Guoxin; Laplanche, Diane; Henryk, Luka; Turlings, Ted C J

    2017-03-01

    Herbivore-induced plant volatiles (HIPVs) are important cues for female parasitic wasps to find hosts. Here, we investigated the possibility that HIPVs may also serve parasitoids as cues to locate mates. To test this, the odour preferences of four braconid wasps - the gregarious parasitoid Cotesia glomerata (L.) and the solitary parasitoids Cotesia marginiventris (Cresson), Microplitis rufiventris Kokujev and Microplitis mediator (Haliday) - were studied in olfactometers. Each species showed attraction to pheromones but in somewhat different ways. Males of the two Cotesia species were attracted to virgin females, whereas females of M. rufiventris were attracted to virgin males. Male and female M. mediator exhibited attraction to both sexes. Importantly, female and male wasps of all four species were strongly attracted by HIPVs, independent of mating status. In most cases, male wasps were also attracted to intact plants. The wasps preferred the combination of HIPVs and pheromones over plant odours alone, except M. mediator, which appears to mainly use HIPVs for mate location. We discuss the ecological contexts in which the combined use of pheromones and HIPVs by parasitoids can be expected. To our knowledge, this is the first study to show that braconid parasitoids use HIPVs and pheromones in combination to locate mates. © 2016 John Wiley & Sons Ltd.

  14. Local and Landscape Drivers of Parasitoid Abundance, Richness, and Composition in Urban Gardens.

    Science.gov (United States)

    Burks, Julia M; Philpott, Stacy M

    2017-04-01

    Urbanization negatively affects biodiversity, yet some urban habitat features can support diversity. Parasitoid wasps, an abundant and highly diverse group of arthropods, can inhabit urban areas and do well in areas with higher host abundance, floral resources, or local or landscape complexity. Parasitoids provide biological control services in many agricultural habitats, yet few studies have examined diversity and abundance of parasitoids in urban agroecosystems to understand how to promote conservation and function. We examined the local habitat and landscape drivers of parasitoid abundance, superfamily and family richness, and parasitoid composition in urban gardens in the California central coast. Local factors included garden size, ground cover type, herbaceous plant species, and number of trees and shrubs. Landscape characteristics included land cover and landscape diversity around gardens. We found that garden size, mulch cover, and urban cover within 500 m of gardens predicted increases in parasitoid abundance within gardens. The height of herbaceous vegetation and tree and shrub richness predicted increases in superfamily and family richness whereas increases in urban cover resulted in declines in parasitoid richness. Abundance of individual superfamilies and families responded to a wide array of local and landscape factors, sometimes in opposite ways. Composition of parasitoid communities responded to changes in garden size, herbaceous plant cover, and number of flowers. Thus, both local scale management and landscape planning may impact the abundance, diversity, and community composition of parasitoids in urban gardens, and may result in differences in the effectiveness of parasitoids in biological control. © The Authors 2017. Published by Oxford University Press on behalf of Entomological Society of America. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  15. Dynamics of a host-parasitoid model with prolonged diapause for parasitoid

    Science.gov (United States)

    Zhao, Min; Zhang, Limin; Zhu, Jun

    2011-01-01

    In this paper, a host-parasitoid model with prolonged diapause for parasitoid is proposed and analyzed. The asymptotic stability analysis of the system is performed. For a biologically reasonable range of parameter values, the global dynamics of the system have been studied numerically. In particular, the effect of prolonged diapause and parasitism on the system has been investigated. Many forms of complex dynamics are observed. The complexities include: (1) chaotic bands with periodic windows; (2) pitchfork and tangent bifurcations; (3) period-doubling and period-halving cascades; (4) intermittency; (5) supertransients; (6) non-unique dynamics, meaning that several attractors coexist; and (7) attractor crises. Furthermore, the complex dynamic behaviors of the model are confirmed by the largest Lyapunov exponents.

  16. Effects of shelf architecture and parasitoid release height on biological control of Plodia interpunctella (Lepidoptera: Pyralidae) eggs by Trichogramma deion (Hymenoptera: Trichogrammatidae).

    Science.gov (United States)

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

    2006-12-01

    The effects of shelving type, packaging, and release height on success of Trichogramma deion Pinto & Oatman (Hymenoptera: Trichogrammatidae) parasitizing Plodia interpunctella (Hübner) (Lepidoptera: Pyralidae) eggs was studied under laboratory conditions. In trials on multipletiered gondola-type or open shelving units, with or without packaging, foraging success was evaluated by comparing parasitism and total mortality rates of sentinel egg disks among shelves after a single point-release of T. deion. Results showed that T. deion parasitized more egg disks and killed more total eggs on open shelves than on gondola shelving. The presence of packaging had no effect on parasitoid foraging on open shelves; however, packaging did interfere with parasitism of P. interpunctella eggs on gondola shelving. Egg parasitism and mortality patterns among shelves were not as evenly distributed on gondola-type shelving compared with open shelving. On gondola shelves without packages, changing the release point of T. deion from the middle to the lowest shelf shifted the distribution of parasitism toward the floor. Gondola shelving, especially in the presence of packaging, reduced foraging efficiency of T. deion for P. interpunctella eggs. Thus, to attain adequate control of P. interpunctella, it may be necessary to use two release heights on gondola shelving.

  17. 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

  18. Communicator Style as a Predictor of Effectiveness and Attractiveness: A Developmental Study.

    Science.gov (United States)

    Norton, Robert W.; And Others

    From a group of 288 college students that completed the Communicator Style Measure (CSM), 72 subjects were randomly assigned to triads in a study exploring the relationships between communicator style, effectiveness, and attractiveness. The 72 subjects were selected by their CSM scores and stratified into three groups (high, medium, and low). The…

  19. Effectiveness and Attractiveness as a Function of Communicator Style in Triads.

    Science.gov (United States)

    Schroeder, Anthony B.

    The purpose of this research was to determine how interactive style influences effectiveness and interpersonal attraction in groups. After college student volunteers completed the Communicator Style Measure (CSM), 72 subjects were selected from three style profiles and assigned to triads that contained high, mid, and low communication style…

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

    NARCIS (Netherlands)

    Dijkstra, P; Buunk, BP; Blanton, H

    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

  1. The Effects of Nonverbal Involvement and Communication Apprehension on State Anxiety, Interpersonal Attraction, and Speech Duration.

    Science.gov (United States)

    Remland, Martin S.; Jones, Tricia S.

    1989-01-01

    Examines whether communication apprehension mediates the effect of nonverbal involvement cues (head nods, eye contact, body orientation, etc.) on state anxiety, interpersonal attraction, and speech duration in information gathering interviews. Finds that nonverbal cues affect loquacity and liking, but that a speaker's communication apprehension…

  2. The Interactive Effects of Counselor Gender, Physical Attractiveness and Status on Client Self-Disclosure.

    Science.gov (United States)

    Kunin, Carla C.; Rodin, Miriam J.

    1982-01-01

    Investigated client self-disclosure and client perception of counselors. Subjects rated counselors on intelligence and empathy, and while role-playing clients in therapy. Clients disclosed more to male counselors when counselors were high in status or attractiveness. Suggests the effect of counselor gender depends on an interaction with other…

  3. Effects of brood size manipulations on sexual attractiveness of offspring in the zebra finch

    NARCIS (Netherlands)

    DeKogel, CH; Prijs, HJ

    In a laboratory study the effect of brood size manipulations on the sexual attractiveness of offspring was investigated. Zebra finches, Taeniopygia guttata, were reared in small or large broods. Young were exchanged so that natural siblings from different rearing conditions could be compared. Birds

  4. Parasitoid searching efficiency links behaviour to population processes

    NARCIS (Netherlands)

    Vet, L.E.M.

    2001-01-01

    Parasitoid searching efficiency is central to parasitoid-host population dynamics, to the evolution of parasitoid and host behaviour, and to the application of parasitoids as natural enemies of insect pests in biological control. Students of parasitoid behaviour attempt to explain variability in

  5. Performance of DNA metabarcoding, standard barcoding, and morphological approach in the identification of host-parasitoid interactions.

    Science.gov (United States)

    Šigut, Martin; Kostovčík, Martin; Šigutová, Hana; Hulcr, Jiří; Drozd, Pavel; Hrček, Jan

    2017-01-01

    in groups with high level of crypsis. This study suggests the potential of metabarcoding for effectively recovering host-parasitoid diversity, together with more accurate identifications obtained from building reliable and comprehensive reference libraries, especially for parasitoids.

  6. 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.

  7. Age-Differential Effects of Job Characteristics on Job Attraction: A Policy-Capturing Study

    Science.gov (United States)

    Zacher, Hannes; Dirkers, Bodil T.; Korek, Sabine; Hughes, Brenda

    2017-01-01

    Based on an integration of job design and lifespan developmental theories, Truxillo et al. (2012) proposed that job characteristics interact with employee age in predicting important work outcomes. Using an experimental policy-capturing design, we investigated age-differential effects of four core job characteristics (i.e., job autonomy, task variety, task significance, and feedback from the job) on job attraction (i.e., individuals' rating of job attractiveness). Eighty-two employees between 19 and 65 years (Mage = 41, SD = 14) indicated their job attraction for each of 40 hypothetical job descriptions in which the four job characteristics were systematically manipulated (in total, participants provided 3,280 ratings). Results of multilevel analyses showed that the positive effects of task variety, task significance, and feedback from the job were stronger for younger compared to older employees, whereas we did not find significant age-differential effects of job autonomy on job attraction. These findings are only partially consistent with propositions of Truxillo et al.'s (2012) lifespan perspective on job design. PMID:28713322

  8. Age-Differential Effects of Job Characteristics on Job Attraction: A Policy-Capturing Study.

    Science.gov (United States)

    Zacher, Hannes; Dirkers, Bodil T; Korek, Sabine; Hughes, Brenda

    2017-01-01

    Based on an integration of job design and lifespan developmental theories, Truxillo et al. (2012) proposed that job characteristics interact with employee age in predicting important work outcomes. Using an experimental policy-capturing design, we investigated age-differential effects of four core job characteristics (i.e., job autonomy, task variety, task significance, and feedback from the job) on job attraction (i.e., individuals' rating of job attractiveness). Eighty-two employees between 19 and 65 years (Mage = 41, SD = 14) indicated their job attraction for each of 40 hypothetical job descriptions in which the four job characteristics were systematically manipulated (in total, participants provided 3,280 ratings). Results of multilevel analyses showed that the positive effects of task variety, task significance, and feedback from the job were stronger for younger compared to older employees, whereas we did not find significant age-differential effects of job autonomy on job attraction. These findings are only partially consistent with propositions of Truxillo et al.'s (2012) lifespan perspective on job design.

  9. Age-Differential Effects of Job Characteristics on Job Attraction: A Policy-Capturing Study

    Directory of Open Access Journals (Sweden)

    Hannes Zacher

    2017-06-01

    Full Text Available Based on an integration of job design and lifespan developmental theories, Truxillo et al. (2012 proposed that job characteristics interact with employee age in predicting important work outcomes. Using an experimental policy-capturing design, we investigated age-differential effects of four core job characteristics (i.e., job autonomy, task variety, task significance, and feedback from the job on job attraction (i.e., individuals' rating of job attractiveness. Eighty-two employees between 19 and 65 years (Mage = 41, SD = 14 indicated their job attraction for each of 40 hypothetical job descriptions in which the four job characteristics were systematically manipulated (in total, participants provided 3,280 ratings. Results of multilevel analyses showed that the positive effects of task variety, task significance, and feedback from the job were stronger for younger compared to older employees, whereas we did not find significant age-differential effects of job autonomy on job attraction. These findings are only partially consistent with propositions of Truxillo et al.'s (2012 lifespan perspective on job design.

  10. 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.

  11. 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.

  12. Early memory in the parasitoid wasp Nasonia vitripennis.

    Science.gov (United States)

    Schurmann, Daria; Kugel, Dominic; Steidle, Johannes L M

    2015-04-01

    We studied early memory in Nasonia vitripennis, a parasitoid of fly pupae and emerging model organism for ecological questions in the context of learning. After associative training consisting of one drilling experience in a host in the presence of cinnamon, females showed a preference to cinnamon for at least 24 h. To study sensitisation, wasps were trained by one drilling in a host without cinnamon. These wasps were not attracted to cinnamon immediately afterwards. Obviously, sensitisation is not involved in early memory. Wasps that were anaesthetised by CO2 directly after associative training did not react to cinnamon 30-45 min later, but after 1 and 24 h. CO2 treatment≥5 min after training did not erase the reaction to cinnamon. This indicates the existence of four early memory phases. (a) One phase<5 min after training, in which CO2 has to be applied to become effective. (b) One subsequent phase which is resistant to CO2. (c) One phase<1 h in which memory can be erased by CO2 treatment directly after training. (d) One phase 1-24 h not affected by CO2 treatment. Together with earlier data this enables us to establish a complete memory structure for N. vitripennis.

  13. Invasive insect herbivores as disrupters of chemically-mediated tritrophic interactions: effects of herbivore density and parasitoid learning

    Science.gov (United States)

    Invasive species of insect herbivores have the potential to interfere with native multitrophic interactions when they invade new environments. For instance, exotic herbivores can affect the chemical cues emitted by plants and disrupt attraction of natural enemies mediated by herbivore-induced plant ...

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

    Directory of Open Access Journals (Sweden)

    Diane B Choi

    2016-07-01

    Full Text Available 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.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.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.

  16. Effective prey attraction in the rare Drosophyllum lusitanicum, a flypaper-trap carnivorous plant.

    Science.gov (United States)

    Bertol, Nils; Paniw, Maria; Ojeda, Fernando

    2015-05-01

    Carnivorous plants have unusually modified leaves to trap insects as an adaptation to low-nutrient environments. Disparate mechanisms have been suggested as luring traits to attract prey insects into their deadly leaves, ranging from very elaborate to none at all. Drosophyllum lusitanicum is a rare carnivorous plant with a common flypaper-trap mechanism. Here we tested whether Drosophyllum plants lure prey insects into their leaves or they act just as passive traps. We compared prey capture between live, potted plants and Drosophyllum-shaped artificial mimics coated with odorless glue. Since this species is insect-pollinated, we also explored the possible existence of a pollinator-prey conflict by quantifying the similarity between the pollination and prey guilds in a natural population. All experiments were done in southern Spain. The sticky leaves of Drosophyllum captured significantly more prey than mimics, particularly small dipterans. Prey attraction, likely exerted by scent or visual cues, seems to be unrelated to pollinator attraction by flowers, as inferred from the low similarity between pollinator and prey insect faunas found in this species. Our results illustrate the effectiveness of this carnivorous species at attracting insects to their flypaper-trap leaves. © 2015 Botanical Society of America, Inc.

  17. 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.

  18. First foreign exploration for asian parasitoids of Drosophila suzukii

    Science.gov (United States)

    The invasive spotted wing drosophila, Drosophila suzukii Matsumura (Dipt.: Drosophilidae), is a native of East Asia and is now widely established in North America and Europe, where it is a serious pest of small and stone fruit crops. The lack of effective indigenous parasitoids of D. suzukii in the ...

  19. Multisensory foraging by hymenopterous parasitoids

    NARCIS (Netherlands)

    Waeckers, 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

  20. Effects of temperature and photoperiod on the reproductive biology and diapause of oobius agrili (Hymenoptera: Encyrtidae), an egg parasitoid of emerald ash borer (Coleoptera: Buprestidae)

    Science.gov (United States)

    Oobius agrili Zhang and Huang is a solitary egg parasitoid of the invasive emerald ash borer, Agrilus planipennis Fairmaire (Coleoptera: Buprestidae) and has been introduced to the United States for biological control. We characterized the weekly survivorship, fecundity, and diapause patterns of bo...

  1. The Effectiveness of Tax Incentives in Attracting Investment : Panel Data Evidence from the CFA Franc Zone

    OpenAIRE

    Van Parys, Stefan; James, Sebastian

    2010-01-01

    In this paper, we investigate to what extent tax incentives are effective in attracting investment in Sub-Saharan Africa. We test the neo-classical investment theory prediction that tax incentives, by lowering the user cost of capital, raise investment. Next to tax incentives, we also estimate the impact on investment of other investment climate variables that are under direct control of the government, such as the transparency and complexity of the tax system, and the legal protection of for...

  2. Recruiting nurses through social media: Effects on employer brand and attractiveness.

    Science.gov (United States)

    Carpentier, Marieke; Van Hoye, Greet; Stockman, Sara; Schollaert, Eveline; Van Theemsche, Bart; Jacobs, Gerd

    2017-11-01

    To investigate whether and how nurses' exposure to a hospital's profile on social media affects their perceptions of the hospital's brand and attractiveness as an employer. Since in many places across the globe hospitals are struggling with nursing shortages, competition is rising to be perceived as an attractive employer by this target group. Organizations are increasingly using social media for recruitment, however, little is known about its effects on potential applicants' perceptions of the organization as an employer. We thus examine whether these effects occur and rely on the media richness theory to explain the mechanisms at play. A between-subjects experimental design was applied. Three conditions were used: a control group, one condition that required visiting the Facebook page of a hospital and one condition that required visiting the LinkedIn page. The focal organization was an existing Belgian hospital which had a LinkedIn and a Facebook page. An online questionnaire was sent to nursing students and employed nurses over 5 months in 2015-2016. Nurses' exposure to the hospital's Facebook or LinkedIn page had a significant positive effect on a majority of the employer brand dimensions, both instrumental and symbolic. In addition, nurses who visited the Facebook page felt more attracted to working at the hospital. Most of these effects were mediated by social presence. Nurses' perceptions of employers can be positively influenced by seeing a hospital's social media page. Hospitals can thus employ social media to improve their employer brand image and attractiveness. © 2017 John Wiley & Sons Ltd.

  3. Biological control of invasive Dryocosmus kuriphilus with introduced parasitoid Torymus sinensis in Croatia, Slovenia and Hungary

    OpenAIRE

    Matošević, Dinka; Lacković, Nikola; Melika, George; Kos, Katarina; Franić, Iva; Kriston, Eva; Bozso, Miklos; Seljak, Gabrijel; Rot, Mojca

    2016-01-01

    Background and purpose: Dryocosmus kuriphilus is considered as one of the major pests of sweet chestnut and the effective method of controlling its populations and damage is the biological control with its introduced parasitoid Torymus sinensis. T. sinensis is a univoltine, host specific parasitoid, phenologically synchronized and morphologically adapted to D. kuriphilus. It has a good dispersal ability, it builds up populations quickly and it effectively controls the pest already few years a...

  4. Face likeability mediates the memory-enhancing effect of face attractiveness in young but not older adults.

    Science.gov (United States)

    Lin, Tian; Lendry, Reesa; Ebner, Natalie C

    2016-11-01

    Evidence of effects of face attractiveness on memory is mixed and little is known about the underlying mechanisms of this relationship. Previous work suggests a possible mediating role of affective responding to faces (i.e., face likeability) on the relationship between face attractiveness and memory. Age-related change in social motivation may reduce the relevance of face attractiveness in older adults, with downstream effects on memory. In the present study, 50 young and 51 older participants were presented with face-trait pairs. Faces varied in attractiveness. Participants then completed a face-trait associative recognition memory task and provided likeability ratings for each face. There was a memory-enhancing effect of face attractiveness in young (but not older) participants, which was partially mediated by face likeability. In addition, more attractive and less attractive (compared to moderately attractive) faces were more likely remembered by both young and older participants. This quadratic effect of face attractiveness on memory was not mediated by face likeability. Findings are discussed in the context of motivational influences on memory that vary with age.

  5. Volatile Organic Compounds Induced by Herbivory of the Soybean Looper Chrysodeixis includens in Transgenic Glyphosate-Resistant Soybean and the Behavioral Effect on the Parasitoid, Meteorus rubens.

    Science.gov (United States)

    Strapasson, Priscila; Pinto-Zevallos, Delia M; Da Silva Gomes, Sandra M; Zarbin, Paulo H G

    2016-08-01

    Transgenic soybean plants (RR) engineered to express resistance to glyphosate harbor a variant of the enzyme EPSPS (5-enolpyruvylshikimate-3-phosphate synthase) involved in the shikimic acid pathway, the biosynthetic route of three aromatic amino acids: phenylalanine, tyrosine, and tryptophan. The insertion of the variant enzyme CP4 EPSPS confers resistance to glyphosate. During the process of genetic engineering, unintended secondary effects are likely to occur. In the present study, we quantified volatile organic compounds (VOCs) emitted constitutively or induced in response to herbivory by the soybean looper Chrysodeixis includens in transgenic soybean and its isogenic (untransformed) line. Since herbivore-induced plant volatiles (HIPVs) are known to play a role in the recruitment of natural enemies, we assessed whether changes in VOC profiles alter the foraging behavior of the generalist endoparasitic larval parasitoid, Meteorus rubens in the transgenic line. Additionally, we assessed whether there was a difference in plant quality by measuring the weight gain of the soybean looper. In response to herbivory, several VOCs were induced in both the conventional and the transgenic line; however, larger quantities of a few compounds were emitted by transgenic plants. Meteorus rubens females were able to discriminate between the odors of undamaged and C. includens-damaged plants in both lines, but preferred the odors emitted by herbivore-damaged transgenic plants over those emitted by herbivore-damaged conventional soybean plants. No differences were observed in the weight gain of the soybean looper. Our results suggest that VOC-mediated tritrophic interactions in this model system are not negatively affected. However, as the preference of the wasps shifted towards damaged transgenic plants, the results also suggest that genetic modification affects that tritrophic interactions in multiple ways in this model system.

  6. Facial attractiveness.

    Science.gov (United States)

    Little, Anthony C

    2014-11-01

    Facial attractiveness has important social consequences. Despite a widespread belief that beauty cannot be defined, in fact, there is considerable agreement across individuals and cultures on what is found attractive. By considering that attraction and mate choice are critical components of evolutionary selection, we can better understand the importance of beauty. There are many traits that are linked to facial attractiveness in humans and each may in some way impart benefits to individuals who act on their preferences. If a trait is reliably associated with some benefit to the perceiver, then we would expect individuals in a population to find that trait attractive. Such an approach has highlighted face traits such as age, health, symmetry, and averageness, which are proposed to be associated with benefits and so associated with facial attractiveness. This view may postulate that some traits will be universally attractive; however, this does not preclude variation. Indeed, it would be surprising if there existed a template of a perfect face that was not affected by experience, environment, context, or the specific needs of an individual. Research on facial attractiveness has documented how various face traits are associated with attractiveness and various factors that impact on an individual's judgments of facial attractiveness. Overall, facial attractiveness is complex, both in the number of traits that determine attraction and in the large number of factors that can alter attraction to particular faces. A fuller understanding of facial beauty will come with an understanding of how these various factors interact with each other. WIREs Cogn Sci 2014, 5:621-634. doi: 10.1002/wcs.1316 CONFLICT OF INTEREST: The author has declared no conflicts of interest for this article. For further resources related to this article, please visit the WIREs website. © 2014 John Wiley & Sons, Ltd.

  7. Sublethal doses of imidacloprid disrupt sexual communication and host finding in a parasitoid wasp

    Science.gov (United States)

    Tappert, Lars; Pokorny, Tamara; Hofferberth, John; Ruther, Joachim

    2017-02-01

    Neonicotinoids are widely used insecticides, but their use is subject of debate because of their detrimental effects on pollinators. Little is known about the effect of neonicotinoids on other beneficial insects such as parasitoid wasps, which serve as natural enemies and are crucial for ecosystem functioning. Here we show that sublethal doses of the neonicotinoid imidacloprid impair sexual communication and host finding in the parasitoid wasp Nasonia vitripennis. Depending on the dose, treated females were less responsive to the male sex pheromone or unable to use it as a cue at all. Courtship behaviour of treated couples was also impeded resulting in a reduction of mating rates by up to 80%. Moreover, treated females were no longer able to locate hosts by using olfactory cues. Olfaction is crucial for the reproductive success of parasitoid wasps. Hence, sublethal doses of neonicotinoids might compromise the function of parasitoid wasps as natural enemies with potentially dire consequences for ecosystem services.

  8. Social dynamics in emergency evacuations: Disentangling crowd's attraction and repulsion effects

    Science.gov (United States)

    Haghani, Milad; Sarvi, Majid

    2017-06-01

    The social dynamics of crowds in emergency escape scenarios have been conventionally modelled as the net effect of virtual forces exerted by the crowd on each individual (as self-driven particles), with the magnitude of the influence formulated as decreasing functions of inter-individual distances and the direction of effect assumed to be transitioning from repulsion to attraction by distance. Here, we revisit this conventional assumption using laboratory experimental data. We show based on robust econometric hypothesis-testing methods that individuals' perception of other escapees differs based on whether those individuals are jamming around exit destinations or are on the move towards the destinations. Also, for moving crowds, it differs based on whether the escape destination chosen by the moving flow is visible or invisible to the individual. The presence of crowd jams around a destination, also the movement of crowd flows towards visible destinations are both perceived on average as repulsion (or disutility) effects (with the former showing significantly larger magnitude than the latter). The movement of crowd flows towards an invisible destination, however, is on average perceived as attraction (or utility) effect. Yet, further hypothesis testing showed that neither of those effects in isolation determines adequately whether an individual would merge with or diverge from the crowd. Rather, the social interaction factors act (at significant levels) in conjunction with the physical factors of the environments (including spatial distances to exit destinations and destinations' visibility). In brief, our finding disentangles the conditions under which individuals are more likely to show mass behaviour from the situations where they are more likely to break from the herd. It identifies two factors that moderate the perception of social interactions, ;crowds' jam/movement status; and ;environmental setup;. Our results particularly challenge the taxonomy of

  9. Plant species loss affects life-history traits of aphids and their parasitoids.

    Directory of Open Access Journals (Sweden)

    Jana S Petermann

    Full Text Available The consequences of plant species loss are rarely assessed in a multi-trophic context and especially effects on life-history traits of organisms at higher trophic levels have remained largely unstudied. We used a grassland biodiversity experiment and measured the effects of two components of plant diversity, plant species richness and the presence of nitrogen-fixing legumes, on several life-history traits of naturally colonizing aphids and their primary and secondary parasitoids in the field. We found that, irrespective of aphid species identity, the proportion of winged aphid morphs decreased with increasing plant species richness, which was correlated with decreasing host plant biomass. Similarly, emergence proportions of parasitoids decreased with increasing plant species richness. Both, emergence proportions and proportions of female parasitoids were lower in plots with legumes, where host plants had increased nitrogen concentrations. This effect of legume presence could indicate that aphids were better defended against parasitoids in high-nitrogen environments. Body mass of emerged individuals of the two most abundant primary parasitoid species was, however, higher in plots with legumes, suggesting that once parasitoids could overcome aphid defenses, they could profit from larger or more nutritious hosts. Our study demonstrates that cascading effects of plant species loss on higher trophic levels such as aphids, parasitoids and secondary parasitoids begin with changed life-history traits of these insects. Thus, life-history traits of organisms at higher trophic levels may be useful indicators of bottom-up effects of plant diversity on the biodiversity of consumers.

  10. 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.

  11. 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

  12. Interaction between the entomopathogenic fungus, Beauveria bassiana (Ascomycota: Hypocreales and the parasitoid wasp, Aphidius colemani Viereck (Hymenoptera: Braconidae

    Directory of Open Access Journals (Sweden)

    F. Emami

    2013-04-01

    Full Text Available The effect of the entomopathogenic fungus, Beauveria bassiana, on the biological characteristics of Aphidius colemani, a parasitoid of the green peach aphid, Myzus persicae, was studied under laboratory conditions. Third-instar nymphs of green peach aphid were infected with 5/3×105 conidia/mL of B. bassiana, which was determined to be the lethal concentration 50 dose. They were then offered to mated female parasitoids for 24 h at different intervals. Results showed that by prolonging the release intervals of parasitoids, the number of mummies and percent emergence of parasitoids were reduced. Moreover, production of male offspring increased in the F1 generation of parasitoids. The interference of B. bassiana with parasitoid development was also studied by first exposing the aphid hosts to the parasitoids for 24 h and subsequently spraying them with B. bassiana 24, 48, 72, and 96 h after exposure. Results showed that by prolonging fungal spraying intervals, the number of mummies and percent emergence of parasitoids were increased. It appeared that the best time for applying B. bassiana would be three to four days after parasitisation.

  13. 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.

  14. Carbohydrate Diet and Reproductive Performance of a Fruit Fly Parasitoid, Diachasmimorpha tryoni

    OpenAIRE

    Zamek, Ashley Louisa; Reynolds, Olivia Louise; Mansfield, Sarah; Micallef, Jessica Louise; Gurr, Geoff Michael

    2013-01-01

    Augmentative releases of parasitoid wasps are often used successfully for biological control of fruit flies in programs worldwide. The development of cheaper and more effective augmentative releases of the parasitoid wasp Diachasmimorpha tryoni (Cameron) (Hymenoptera: Braconidae) may allow its use to be expanded to cover Queensland fruit fly, Bactrocera tryoni (Froggatt) (Diptera: Tephritidae), a serious pest of many vegetables and most fruit production in Australia. This demands a fuller und...

  15. Predation on rose galls: parasitoids and predators determine gall size through directional selection.

    Directory of Open Access Journals (Sweden)

    Zoltán László

    Full Text Available Both predators and parasitoids can have significant effects on species' life history traits, such as longevity or clutch size. In the case of gall inducers, sporadically there is evidence to suggest that both vertebrate predation and insect parasitoid attack may shape the optimal gall size. While the effects of parasitoids have been studied in detail, the influence of vertebrate predation is less well-investigated. To better understand this aspect of gall size evolution, we studied vertebrate predation on galls of Diplolepis rosae on rose (Rosa canina shrubs. We measured predation frequency, predation incidence, and predation rate in a large-scale observational field study, as well as an experimental field study. Our combined results suggest that, similarly to parasitoids, vertebrate predation makes a considerable contribution to mortality of gall inducer larvae. On the other hand, its influence on gall size is in direct contrast to the effect of parasitoids, as frequency of vertebrate predation increases with gall size. This suggests that the balance between predation and parasitoid attack shapes the optimal size of D. rosae galls.

  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.

  17. Latitudinal variation in parasitoid guild composition and parasitism rates of North American hawthorn infesting Rhagoletis.

    Science.gov (United States)

    Rull, Juan; Wharton, Robert; Feder, Jeffrey L; Guillén, Larissa; Sivinski, John; Forbes, Andrew; Aluja, Martín

    2009-06-01

    Rhagoletis pomonella (Diptera: Tephritidae) populations in North America have diverged by exploiting host plants with varying fruiting phenologies in environments that differ markedly in temperature and humidity. As a result, four genetically and ecologically distinct R. pomonella populations that display partial reproductive isolation have evolved. Host shifting by Rhagoletis and similar evolutionary histories could have had cascading effects across trophic levels, influencing the diversity and distribution of associated parasitoid guilds. To establish the basis for a future understanding of the possible effect of divergence in R. pomonella populations on the parasitoids attacking these flies, we surveyed parasitoids from five different species of hawthorns distributed over 15 states in México and 2 states in the midwestern United States. Emerging parasitoids were identified, parasitism rates were calculated, and regional fly and parasitoid emergence schedules were determined. Parasitism rate, emergence schedules, Shannon-Weiner diversity indexes, and species accumulation curves were compared across three main geographical regions. Parasitism levels varied greatly among regions from an overall high of 27.2% in the United States to 5.5% in the Sierra Madre Oriental (SMO) mountains of Mexico, to as low as 0.19% in the Eje Volcánico Trans Mexicano (EVTM). Shannon-Weiner diversity indexes showed that parasitoid species diversity was similar across the distribution range of R. pomonella in Mexico and the United States because of the fact that total parasitism was dominated by only two species, one of them recovered across the whole North American range of hawthorn infesting Rhagoletis. Nevertheless, eight parasitoids were found attacking R. pomonella in Mexico compared with only four collected in the United States. Only two diapausing parasitoid species were shared between the U.S. and Mexican R. pomonella populations: Utetes canaliculatus and Diachasmimorpha mellea

  18. Effects on eastern larch beetle of its natural attractant and synthetic pheromones in Alaska.

    Science.gov (United States)

    Richard A. Werner; Malcom M. Furniss; Thomas. Ward

    1981-01-01

    Traps baited with Seudenol + a-pinene caught 87 percent more eastern larch beetles, Dendroctonus simplex LeConte, than did tamarack logs infested with females. Male beetles responded to the synthetic attractant in greater numbers than females. Male beetles were not attracted to frontalin, a principal attractant of the closely related Douglas-fir...

  19. 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. © The Authors 2016. Published by Oxford University Press on behalf of Entomological Society of America. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  20. Revisiting the Red Effect on Attractiveness and Sexual Receptivity : No Effect of the Color Red on Human Mate Preferences

    NARCIS (Netherlands)

    Peperkoorn, L.S.; Roberts, S. Craig; Pollet, Thomas V.

    2016-01-01

    Color-in-context theory is the first theoretical framework for understanding color effects in human mate preferences, arguing that red clothing enhances attractiveness ratings. Here we present three empirical studies failing to support this prediction. We aimed to extend the current literature by

  1. Effects of topology on the adsorption of singly tethered ring polymers to attractive surfaces.

    Science.gov (United States)

    Li, Bing; Sun, Zhao-Yan; An, Li-Jia

    2015-07-14

    We investigate the effect of topology on the equilibrium behavior of singly tethered ring polymers adsorbed on an attractive surface. We focus on the change of square radius of gyration Rg(2), the perpendicular component Rg⊥(2) and the parallel component Rg‖(2) to the adsorbing surface, the mean contacting number of monomers with the surface , and the monomer distribution along z-direction during transition from desorption to adsorption. We find that both of the critical point of adsorption εc and the crossover exponent ϕ depend on the knot type when the chain length of ring ranges from 48 to 400. The behaviors of Rg(2), Rg⊥(2), and Rg‖(2) are found to be dependent on the topology and the monomer-surface attractive strength. At weak adsorption, the polymer chains with more complex topology are more adsorbable than those with simple topology. However, at strong adsorption, the polymer chains with complex topology are less adsorbable. By analyzing the distribution of monomer along z-direction, we give a possible mechanism for the effect of topology on the adsorption behavior.

  2. Effects of attractive colloids on the phase separation behaviors of binary polymer blends

    Science.gov (United States)

    Zhang, Xinghua; Chen, Yunlin; Qu, Lijian; Yan, Dadong

    2013-08-01

    The attractive colloids are added as fillers to control the phase behaviors of binary polymer blends. Because the colloids attract both components in the blends, aggregates are formed by the colloids coated with both kinds of polymer brushes. The aggregation results in two contradictory effects on the phase separation. First, the formation of aggregate decreases the translational entropy, which promotes the phase separation. On the other hand, the phase separation causes the extra free energy penalty due to the stretch of the chains attaching on the colloids, which prevents the phase separation. Furthermore, as the concentration or adsorbability of the colloids increases the local fluctuations within the aggregates become important. This results in a transition from the macro-phase separation to the micro-phase separation and the existence of the Lifshitz point. All of these effects lead to diverse phase behaviors in the polymer nanocomposites system. In present work, these behaviors are studied theoretically by the random phase approximation in a model system.

  3. 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.

  4. Evaluating the attractiveness and effectiveness of artificial coral reefs as a recreational ecosystem service.

    Science.gov (United States)

    Belhassen, Yaniv; Rousseau, Meghan; Tynyakov, Jenny; Shashar, Nadav

    2017-12-01

    Artificial reefs are increasingly being used around the globe to attract recreational divers, for both environmental and commercial reasons. This paper examines artificial coral reefs as recreational ecosystem services (RES) by evaluating their attractiveness and effectiveness and by examining divers' attitudes toward them. An online survey targeted at divers in Israel (n = 263) indicated that 35% of the dives in Eilat (a resort city on the shore of the Red Sea) take place at artificial reefs. A second study monitored divers' behavior around the Tamar artificial reef, one of the most popular submerged artificial reefs in Eilat, and juxtaposed it with divers' activities around two adjacent natural reefs. Findings show that the average diver density at the artificial reef was higher than at the two nearby natural knolls and that the artificial reef effectively diverts divers from natural knolls. A third study that examined the attitudes towards natural vs. artificial reefs found that the artificial reefs are considered more appropriate for training, but that divers feel less relaxed around them. By utilizing the RES approach as a framework, the study offers a comprehensive methodology that brings together the aesthetic, behavioral, and attitudinal aspects in terms of which artificial reefs can be evaluated. Copyright © 2017 Elsevier Ltd. All rights reserved.

  5. The Effect of Attractiveness on Food Sharing Preferences in Human Mating Markets

    Directory of Open Access Journals (Sweden)

    Michael Stirrat

    2011-01-01

    Full Text Available The current study explored how physical attractiveness affects food sharing by studying payment preferences for hypothetical romantic dinner dates (a hypothetical mating market. We analyzed payment preferences, self-rated attractiveness, and rated attractiveness for hypothetical dates in 416 participants. We hypothesized that (1 men would be more likely to prefer to pay than would women, (2 attractive individuals of both sexes would be less willing to pay, and (3 preferences to enter an exchange would be influenced by the attractiveness of prospective partners such that (3a men would prefer to pay for attractive women, and (3b women would prefer to be paid for by attractive men. All hypotheses were supported by our results. Individuals with higher self-rated attractiveness were more likely to prefer that their date would pay for the meal, and we found clear sex differences in how the attractiveness of potential dates affected payment preferences. Male participants preferred to pay for dates that had higher facial attractiveness, while female participants preferred that attractive men would pay. Individuals show condition dependent financial preferences consistent with the provisioning hypothesis in this mating market that are adaptive to evaluations of their own quality and that of prospective partners.

  6. 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

  7. Pengaruh lama ketiadaan inang terhadap kapasitas reproduksi parasitoid Snellenius manilae Ashmead (Hymenoptera: Braconidae

    Directory of Open Access Journals (Sweden)

    Mohamad Eldiary Akbar

    2015-09-01

    Full Text Available The objective of this research was to study the  influence  of host deprivation on the oviposition and physiological condition of Snellenius manilae Ashmead. The research was conducted at Laboratory of Bioecology of Parasitoid and Predator, Department of Plant Protection, Faculty of Agriculture, IPB. Ten parasitoids of the same age and cohort were used in this experiment. Deprivation of hosts were done for 1, 2, 3, 4, 5, 6 and 7 days at the beginning and toward the end of their life. All hosts were replaced every 24 hours. Result indicated that host deprivation affects the reproductive capacity of Snellenius manilae. Even though parasitoids were able to lay eggs even when they were deprived of hosts for seven consecutive days, the overall results of host deprivation experiment showed that the length and timing of deprivation period can affect reproductive capacity. Deprivation of hosts tends to increase the parasitism rate and the numbers of eggs laid upon their first encounter of hosts after the treatment. The difference is more pronounced on treatements that allowed parasitism to occur before the deprivation treatment. However, the overall results suggests that deprivation overall decrease the reproductive capacity of the parasitoid. The longevity of deprived individuals was also lengthened. Parasitoids that were given host before deprivation treatments tend to produced more eggs than those were not. These results showed that deprivation of hosts in the field may affect the effectiveness of parasitoids and the success of biological control.

  8. Effect of surface roughness on van der Waals and Casimir-Polder/Casimir attraction energies

    Science.gov (United States)

    Makeev, Maxim A.

    2017-09-01

    A theoretical model is devised to assess effects of surface roughness on dispersion interactions between macroscopic bodies, bounded by self-affine fractal surfaces and separated by a vacuum gap. The rough-surface profiles are described statistically by the saturation values of surface width and the correlation lengths; i.e., in terms of experimentally measurable quantities. The model devised takes into account the separation distance-dependent nature of dispersive interactions. The case of non-retarded van der Waals interactions, known to operate at smaller separation distances between the bodies, and that of retarded attractions, operative at larger separation length-scales, are treated separately in this work. Analytical formulae for the roughness corrections are deduced for the two aforementioned types of attractions. The model is employed to compute roughness corrections to interactions between an extended body, bounded by a self-affine surface, and: a) a point-like adherent; and b) a planar half-space. Furthermore, the roughness-induced corrections to dispersive interaction energies between half-spaces, both bounded by self-affine surfaces, are obtained under assumption that the corresponding surface profiles are not correlated. The predictions of the model are compared with some previously reported theoretical studies and available experimental data on the theme of dispersive adhesion between macroscopic bodies.

  9. 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.

  10. Effect of incentives on the financial attractiveness of solar industrial process heating in India★

    Directory of Open Access Journals (Sweden)

    Sharma Ashish K.

    2017-01-01

    Full Text Available India has a huge industrial demand for process heating at temperatures that can be provided with commercially available solar collectors. Government of India with support from multi-lateral agencies has initiated an ambitious programme for promoting large scale adoption of Solar Industrial Process Heating (SIPH in the industrial sector of the country. This paper presents the details of an attempt to study the effect of several existing and potential incentives on the financial attractiveness of SIPH systems in India. A case of solar process heating in dairy industry has been presented to demonstrate the relative efficacy of different incentives on the economics of SIPH systems in terms of their impact on levelized cost of useful thermal energy delivered. Finally, policy implications of the results obtained have been discussed.

  11. Pretty Pleases: The Effects of Physical Attractiveness, Race, and Sex on Receiving Help

    Science.gov (United States)

    Benson, Peter L.; And Others

    1976-01-01

    Investigates whether favoritism for the physically attractive, a phenomenon demonstrated almost exclusively on the basis of rating scales, generalizes to nonreactive, behavioral helping responses. (Editor)

  12. 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...

  13. 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

    2015-10-16

    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.

  14. Altruists Attract

    Directory of Open Access Journals (Sweden)

    Daniel Farrelly

    2007-04-01

    Full Text Available Explaining human cooperation continues to present a challenge because it goes beyond what is predicted by established theories of kinship and reciprocal altruism. Little attention has been paid to the sexual selection hypothesis that proposes that cooperation can act as a display that attracts mates. The costs of cooperating are then offset not by kinship or reciprocation but by increased mating success. Here we present results from a series of experiments which show that, as predicted by the sexual selection hypothesis, people preferentially direct cooperative behavior towards more attractive members of the opposite sex. Furthermore, cooperative behavior increases the perceived attractiveness of the cooperator. Economically costly behaviors can therefore bring benefits through mate choice and sexual selection should be regarded as an evolutionary mechanism capable of promoting cooperation.

  15. Effects of acute nicotine and alcohol on the rating of attractiveness in social smokers and alcohol drinkers.

    Science.gov (United States)

    Attwood, Angela S; Penton-Voak, Ian S; Goodwin, Christine; Munafò, Marcus R

    2012-09-01

    Nicotine and alcohol are often consumed together. Previous research suggests that both can independently increase the perceived attractiveness of social stimuli, which may be a mechanism that drives continued use. This study examined whether there was an additive effect of nicotine and alcohol on perceived attractiveness of social and environmental stimuli. Male and female (n=96) social alcohol consumers and light cigarette smokers (no more than 14 cigarettes per week) were randomized to smoke either a nicotinized or denicotinized cigarette and drink either an alcoholic or non-alcoholic (placebo) beverage. The primary outcome was attractiveness ratings of facial and landscape stimuli. Secondary outcomes were self-report mood and craving. There was a main effect of drink (p=.031) and a trend toward a main effect of cigarette (p=.057) with higher ratings of attractiveness after alcohol compared to placebo and after a nicotinized cigarette compared to a denicotinized cigarette. Nicotine and alcohol appeared to work additively on ratings of attractiveness, with the highest ratings in the nicotine/alcohol group. There were no interactions between drink, cigarette and stimulus type. When co-administered, nicotine and alcohol consumption resulted in the highest perceptions of attractiveness across all stimulus types. This additive effect may be a mechanism by which administration of one drug reinforces use of the other, and which leads to an increased likelihood of habitual consumption and relapse. Copyright © 2012 Elsevier Ireland Ltd. All rights reserved.

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

    Science.gov (United States)

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

  17. 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.

  18. Effects of bark beetle pheromones on the attraction of Monochamus alternatus to pine volatiles

    Science.gov (United States)

    Jian-Ting Fan; Daniel Miller; Long-Wa Zhang; Jiang-Hua Sun

    2010-01-01

    We evaluated the attraction of Monochamus alternatus Hope (Coleoptera: Cerambycidae), Dryocoetes luteus Blandford and Orthotomicus erosusWollaston (Coleoptera: Curculionidae: Scolytinae) to multiple-funnel traps baited with the pine volatiles, ethanol and (+)-α-pinene and the bark beetle pheromones, ipsenol and ipsdienol. M. alternatus were attracted to traps baited...

  19. The Effects of Sensation Seeking, Physical Attractiveness of Stimuli, and Exposure Frequency on Liking

    Science.gov (United States)

    Horai, Joann

    1976-01-01

    Males (N=54) and 46 females who scored high or low on a sensation seeking scale were exposed to slides of physically attractive or unattractive person stimuli. High sensation seekers both liked and expected to recognize the physically attractive persons in the future more than the physically unattractive persons. (Author)

  20. Effects of Five Naturally Occurring Sugars on the Longevity, Oogenesis, and Nutrient Accumulation Pattern in Adult Females of the Synovigenic Parasitoid Neochrysocharis formosa (Hymenoptera: Eulophidae).

    Science.gov (United States)

    Wang, W; Lu, S-L; Liu, W-X; Cheng, L-S; Zhang, Y-B; Wan, F-H

    2014-12-01

    Neochrysocharis formosa (Westwood) (Hymenoptera: Eulophidae), one of the dominant natural enemies of agromyzid leafminers, is a synovigenic parasitoid. We compared the longevity, oogenesis, and nutrient levels of female wasps provided with 10% solutions of five naturally occurring sugars. All five sugars significantly increased the longevity of female wasps, which was 6.5-9.3-fold higher than that of parasitoids provided with water only. We found no significant difference in longevity of female wasps fed on glucose versus fructose or trehalose versus melezitose, but longevity of wasps fed on glucose or fructose was significantly longer than those fed on trehalose or melezitose. Also, we examined the oosorption capability of wasps fed on the five sugars. Some mature eggs were present in the ovaries of newly emerged females, but these were fully reabsorbed within 72 h when wasps were starved. Once wasps were fed with any of the sugars, the number of mature eggs increased at first and then decreased due to oosorption. The longevity and oogenesis dynamics of female wasps fed on five sugars were related with their function of hydrolysis and digestion. As female wasps have no lipogenesis capability, by acquiring exogenous sugars for oogenesis, they can either maintain or exceed the original level of capital nutrients held on adult emergence because none of the wasps' glycogen need be metabolized to burn as sugar.

  1. Impact of water-deficit stress on tritrophic interactions in a wheat-aphid-parasitoid system.

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    Syed Suhail Ahmed

    Full Text Available Increasing temperature and CO2 concentrations can alter tritrophic interactions in ecosystems, but the impact of increasingly severe drought on such interactions is not well understood. We examined the response of a wheat-aphid-parasitoid system to variation in water-deficit stress levels. Our results showed that arid area clones of the aphid, Sitobion avenae (Fabricius, tended to have longer developmental times compared to semiarid and moist area clones, and the development of S. avenae clones tended to be slower with increasing levels of water-deficit. Body sizes of S. avenae clones from all areas decreased with increasing water-deficit levels, indicating their declining adaptation potential under drought. Compared to arid area clones, moist area clones of S. avenae had a higher frequency of backing under severe water stress only, but a higher frequency of kicking under well-watered conditions only, suggesting a water-deficit level dependent pattern of resistance against the parasitoid, Aphidius gifuensis (Ashmead. The number of S. avenae individuals attacked by the parasitoid in 10 min showed a tendency to decrease with increasing water-deficit levels. Clones of S. avenae tended to have lower parasitism rates under treatments with higher water-deficit levels. The development of the parasitoid tended to be slower under higher levels of water-deficit stress. Thus, the bottom-up effects of water-deficit stressed plants were negative on S. avenae. However, the top-down effects via parasitoids were compromised by water-deficit, which could favor the growth of aphid populations. Overall, the first trophic level under water-deficit stress was shown to have an indirect and negative impact on the third trophic level parasitoid, suggesting that parasitoids could be increasingly vulnerable in future warming scenarios.

  2. Effects of putative male pheromones on female ratings of male attractiveness: influence of oral contraceptives and the menstrual cycle.

    Science.gov (United States)

    Thorne, Frances; Neave, Nick; Scholey, Andrew; Moss, Mark; Fink, Bernhard

    2002-08-01

    Previous research has revealed that natural and synthetic pheromones can enhance ratings of opposite sex attractiveness. The present study investigated the effects of exposure to male axillary secretions on female ratings of the sexual attractiveness of male stimuli. Thirty-two female undergraduates, half of whom were contraceptive pill users, rated male vignette characters and photographs of male faces on aspects of attractiveness. On two separate study days, corresponding to different phases of their menstrual cycle, stimuli were presented while exposed to male axillary pheromones and under a control condition (no pheromone). The order of testing was balanced with respect to pheromone/control condition and menstrual cycle phase. Pheromone exposure resulted in significantly higher attractiveness ratings of vignette characters and faces. Use of the contraceptive pill or menstrual cycle phase had equivocal effects on some vignette items and neither had any influence on female ratings of male facial attractiveness. The results of this study suggest that exposure to natural male axillary pheromones can significantly enhance female perceptions of various aspects of male attractiveness.

  3. The effects of van der Waals attractions on cloud droplet growth by coalescence

    Science.gov (United States)

    Rogers, Jan R.; Davis, Robert H.

    1990-01-01

    The inclusion of van der Waals attractions in the interaction between cloud droplets has been recently shown to significantly increase the collision efficiencies of the smaller droplets. In the current work, these larger values for the collision efficiencies are used in a population dynamics model of the droplet size distribution evolution with time, in hopes of at least partially resolving the long-standing paradox in cloud microphysics that predicted rates of the onset of precipitation are generally much lower than those which are observed. Evolutions of several initial cloud droplet spectra have been tracked in time. Size evolutions are compared as predicted from the use of collision efficiencies computed using two different models to allow for droplet-droplet contact: one which considers slip flow effects only, and one which considers the combined effects of van der Waals forces and slip flow. The rate at which the droplet mass density function shifts to larger droplet sizes is increased by typically 20-25 percent, when collision efficiencies which include van der Waals forces are used.

  4. The effect of self-serving attribution on attraction in additive- and conjunctive-task groups.

    Science.gov (United States)

    Uraz, G; Aydin, O

    1995-04-01

    The prediction that the effect of self-serving attribution on personal attraction will vary according to task type was tested. Twenty-four groups of Turkish students, each consisting of 1 participant and 3 confederates, received success feedback after having performed either an additive or a conjunctive task. Two of the confederates made either self-serving or group-serving attributions, whereas the 3rd confederate attributed success to the collective efforts of all group members. Following these attributions, the participants filled out a form to indicate the degree to which they preferred each member as a friend and a work mate. Self-serving attributors in the conjunctive-task condition were less preferred as friends than the self-serving attributors in the additive-task condition. Also, the additive-task participants' ratings for other group members were systematically higher than those of the conjunctive-task participants. Thus, there was a main effect of task type for both friends and workmates.

  5. Carbohydrate diet and reproductive performance of a fruit fly parasitoid, Diachasmimorpha tryoni.

    Science.gov (United States)

    Zamek, Ashley Louisa; Reynolds, Olivia Louise; Mansfield, Sarah; Micallef, Jessica Louise; Gurr, Geoff Michael

    2013-01-01

    Augmentative releases of parasitoid wasps are often used successfully for biological control of fruit flies in programs worldwide. The development of cheaper and more effective augmentative releases of the parasitoid wasp Diachasmimorpha tryoni (Cameron) (Hymenoptera: Braconidae) may allow its use to be expanded to cover Queensland fruit fly, Bactrocera tryoni (Froggatt) (Diptera: Tephritidae), a serious pest of many vegetables and most fruit production in Australia. This demands a fuller understanding of the parasitoid's reproductive biology. In this study, mating status, fecundity, and size of female D. tryoni were determined under laboratory conditions. A range of pre-release diets, 10% concentrations of honey, white sugar, and golden syrup, were also assessed in the laboratory. Mature egg loads and progeny yields of mated and unmated parasitoid females were statistically similar, demonstrating that mating status was not a determinant of parasitoid performance. Female lifespan was not negatively impacted by the act of oviposition, though larger females carried more eggs than smaller individuals, indicating a need to produce large females in mass-rearing facilities to maintain this trait. White sugar gave the highest adult female lifespan, while honey and golden syrup shared similar survivorship curves, all significantly greater compared with water control females. Pre-release feeding of D. tryoni, particularly with white sugar, may enhance the impact of released parasitoids on B. tryoni. These findings are important because honey is currently the standard diet for mass-reared braconids, but white sugar is less than one-third the cost of other foods; however further work is required to assess postrelease performance of the parasitoid.

  6. Shifts in metabolomic profiles of the parasitoid Nasonia vitripennis associated with elevated cold tolerance induced by the parasitoid's diapause, host diapause and host diet augmented with proline.

    Science.gov (United States)

    Li, Yuyan; Zhang, Lisheng; Chen, Hongyin; Koštál, Vladimir; Simek, Petr; Moos, Martin; Denlinger, David L

    2015-08-01

    The ectoparasitoid wasp, Nasonia vitripennis can enhance its cold tolerance by exploiting a maternally-induced larval diapause. A simple manipulation of the fly host diapause status and supplementation of the host diet with proline also dramatically increase cold tolerance in the parasitoid. In this study, we used a metabolomics approach to define alterations in metabolite profiles of N. vitripennis caused by diapause in the parasitoid, diapause of the host, and augmentation of the host's diet with proline. Metabolic profiles of diapausing and nondiapausing parasitoid were significantly differentiated, with pronounced distinctions in levels of multiple cryoprotectants, amino acids, and carbohydrates. The dynamic nature of diapause was underscored by a shift in the wasp's metabolomic profile as the duration of diapause increased, a feature especially evident for increased concentrations of a suite of cryoprotectants. Metabolic pathways involved in amino acid and carbohydrate metabolism were distinctly enriched during diapause in the parasitoid. Host diapause status also elicited a pronounced effect on metabolic signatures of the parasitoid, noted by higher cryoprotectants and elevated compounds derived from glycolysis. Proline supplementation of the host diet did not translate directly into elevated proline in the parasitoid but resulted in an alteration in the abundance of many other metabolites, including elevated concentrations of essential amino acids, and reduction in metabolites linked to energy utilization, lipid and amino acid metabolism. Thus, the enhanced cold tolerance of N. vitripennis associated with proline augmentation of the host diet appears to be an indirect effect caused by the metabolic perturbations associated with diet supplementation. Copyright © 2015 Elsevier Ltd. All rights reserved.

  7. 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.

  8. 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.

  9. Effects of attractiveness and status in dating desire in homosexual and heterosexual men and women.

    Science.gov (United States)

    Ha, Thao; van den Berg, Judith E M; Engels, Rutger C M E; Lichtwarck-Aschoff, Anna

    2012-06-01

    The present study examined partner preferences of homosexual and heterosexual men and woman, focusing on attractiveness and status. Homosexual (N=591 men; M age=28.87 years, SD=10.21; N=249 women; M age=33.36 years, SD=13.12) and heterosexual participants (N=346 men; M age=39.74 years, SD=14.26; N=400 women; M age=35.93 years, SD=13.72) rated the importance of attractiveness and social status of potential partners and then, in a vignette test, expressed their desire to date hypothetical potential partners based on photographs that varied in attractiveness and status-related profiles. With ratings, heterosexual men valued attractiveness the most, followed by homosexual men, heterosexual women, and homosexual women. Heterosexual women rated social status as most important. When status profiles were manipulated and accompanied with photographs of faces, the pattern of differences between homosexuals and heterosexuals supported the self-reported results. Overall, homosexual men and women have similar mate preferences to heterosexual men and women by showing more dating desire for attractive and high social status persons. Compared to attractiveness, status played a smaller role in dating desire.

  10. 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.

  11. Repellent effect of some household products on fly attraction to cadavers.

    Science.gov (United States)

    Charabidze, Damien; Bourel, Benoit; Hedouin, Valery; Gosset, Didier

    2009-08-10

    The most common task of a forensic entomologist is to determine an accurate minimum post-mortem interval (PMI) using necrophagous fly larvae found on carrion. More often, blowflies (Diptera: Calliphoridae) are the first insects to detect the cadaver and, if the circumstances are favourable, to leave eggs on the body. However, several studies reveal that products such as gas or paint found on the cadaver induce a delay in the colonisation of the body, leading to an under-estimate of the PMI. Six common household products (gas, mosquito citronella repellent, perfume, bleach, hydrochloric acid and soda) were added to dead rats (Rattus norvegicus) in a field (Lille Forensic Institute, France). The presence of necrophagous flies was checked at regular intervals during 1 month. This experiment was repeated at the same period for four consecutive years. Results clearly showed the repellent effect of three of the six tested substances: gas (petroleum spirit), perfume and mosquito citronella repellent, which resulted in a mean delay of several days in the appearance of the first Dipteran species. Experiments were then carried out in controlled conditions in order to confirm previous observations. An olfactometer was specially designed to observe the behaviour of female Calliphora vicina (Diptera: Calliphoridae) in response to mice (Mus musculus) cadaver odour stimuli combined with household products. Dead mouse odour was a strong attractive stimulus for most of the tested individuals. Furthermore, it was noticed that the presence of mosquito citronella repellent, perfume, hydrochloric acid and paradichlorobenzene produced a significant repellent effect on female flies. All these results together confirm the repellent effect of some household products on flies and the necessity for forensic entomologists to consider this hypothesis when estimating the PMI.

  12. 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

  13. Application of Nuclear Techniques to Improve the Mass Production and Management of Fruit Fly Parasitoids

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    Jorge Hendrichs

    2012-10-01

    Full Text Available The use of irradiated hosts in mass rearing tephritid parasitoids represents an important technical advance in fruit fly augmentative biological control. Irradiation assures that fly emergence is avoided in non-parasitized hosts, while at the same time it has no appreciable effect on parasitoid quality, i.e., fecundity, longevity and flight capability. Parasitoids of fruit fly eggs, larvae and pupae have all been shown to successfully develop in irradiated hosts, allowing a broad range of species to be shipped and released without post-rearing delays waiting for fly emergence and costly procedures to separate flies and wasps. This facilitates the early, more effective and less damaging shipment of natural enemies within hosts and across quarantined borders. In addition, the survival and dispersal of released parasitoids can be monitored by placing irradiated sentinel-hosts in the field. The optimal radiation dosages for host-sterility and parasitoid-fitness differ among species, and considerable progress has been made in integrating radiation into a variety of rearing procedures.

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

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    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.

  15. 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.

  16. 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.

  17. Keanekaragaman spesies parasitoid telur Helicoverpa armigera (Hübner pada sistem tanam monokultur dan polikultur kapas

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    nurindah nurindah

    2017-02-01

    Full Text Available Polyculture system is one of techniques in pest management. In Indonesia, cotton is always intercropped with second food crops such as maize, soybean, mungbean or peanut. This research was aimed to evaluate the effect of culture system, i.e. cotton monoculture vs. cotton intercropped with soybean on the increase of species diversity of H. armigera egg parasitoids and the parasitoid contribution to mortality of H. armigera. The research was arranged in a split plot design with two main factors: three cotton varieties with three levels of trichome density (Tamcot SP 37, Kanesia 8 and LRA 5166 and the subplots were two cultivation systems (cotton monoculture and polyculture, with three replicates. Observations were made by collecting H. armigera eggs on population of first generation (45 days after planting and second generation (75 DAP. The results showed that on cotton polyculture the egg parasitoid complex which consisted of Trichogramma spp. and Trichogrammatoidea spp. was higher than that in cotton monoculture and so was the egg parasitism level. The increase of egg parasitism was 24% in the first generation and 15% in the second generation. Parasitoid species found belonged to the genera Trichogramma and Trichogrammatoidea. In the parasitoid complex, Trichogrammatoidea armigera was dominant on the first generation and Trichogramma chilotraeae on the second. The domination succession could be as a result of the higher host-searching capacity of T. chilotraeae than that of T. armigera.

  18. 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.

  19. Potential Host Manipulation by the Aphid Parasitoid Aphidius avenae to Enhance Cold Tolerance

    Science.gov (United States)

    Alford, Lucy; Androdias, Annabelle; Franco, Thomas; Pierre, Jean-Sébastien; Burel, Françoise; van Baaren, Joan

    2016-01-01

    During parasitoid development, the immature parasitoid is confined to the host species. As a result, any potential to modify the physiology or behaviour of the host could play an important role in parasitoid fitness. The potential for host manipulation by the aphid parasitoid Aphidius avenae to increase cold thermotolerance was investigated using the aphid host species Metopolophium dirhodum and Sitobion avenae. Aphids were parasitized at L3/L4 instar stage (5 d old) and allowed to develop into pre-reproductive adults (10 d old) containing a 5 d old parasitoid larva. A control group was created of non-parasitized pre-reproductive adults (10 d old). The inherent physiological thermotolerance (LT50) and potential behavioural thermoregulation (behaviour in a declining temperature regime) of parasitized and non-parasitized aphids were investigated. Results revealed no effect of parasitism on the physiological thermotolerance of S. avenae and M. dirhodum. Significant differences in the behaviour of parasitized and non-parasitized aphids were observed, in addition to differences between host species, and such behaviours are discussed in view of the potential for host manipulation. PMID:28006018

  20. Potential Host Manipulation by the Aphid Parasitoid Aphidius avenae to Enhance Cold Tolerance.

    Science.gov (United States)

    Alford, Lucy; Androdias, Annabelle; Franco, Thomas; Pierre, Jean-Sébastien; Burel, Françoise; van Baaren, Joan

    2016-01-01

    During parasitoid development, the immature parasitoid is confined to the host species. As a result, any potential to modify the physiology or behaviour of the host could play an important role in parasitoid fitness. The potential for host manipulation by the aphid parasitoid Aphidius avenae to increase cold thermotolerance was investigated using the aphid host species Metopolophium dirhodum and Sitobion avenae. Aphids were parasitized at L3/L4 instar stage (5 d old) and allowed to develop into pre-reproductive adults (10 d old) containing a 5 d old parasitoid larva. A control group was created of non-parasitized pre-reproductive adults (10 d old). The inherent physiological thermotolerance (LT50) and potential behavioural thermoregulation (behaviour in a declining temperature regime) of parasitized and non-parasitized aphids were investigated. Results revealed no effect of parasitism on the physiological thermotolerance of S. avenae and M. dirhodum. Significant differences in the behaviour of parasitized and non-parasitized aphids were observed, in addition to differences between host species, and such behaviours are discussed in view of the potential for host manipulation.

  1. Potential Host Manipulation by the Aphid Parasitoid Aphidius avenae to Enhance Cold Tolerance.

    Directory of Open Access Journals (Sweden)

    Lucy Alford

    Full Text Available During parasitoid development, the immature parasitoid is confined to the host species. As a result, any potential to modify the physiology or behaviour of the host could play an important role in parasitoid fitness. The potential for host manipulation by the aphid parasitoid Aphidius avenae to increase cold thermotolerance was investigated using the aphid host species Metopolophium dirhodum and Sitobion avenae. Aphids were parasitized at L3/L4 instar stage (5 d old and allowed to develop into pre-reproductive adults (10 d old containing a 5 d old parasitoid larva. A control group was created of non-parasitized pre-reproductive adults (10 d old. The inherent physiological thermotolerance (LT50 and potential behavioural thermoregulation (behaviour in a declining temperature regime of parasitized and non-parasitized aphids were investigated. Results revealed no effect of parasitism on the physiological thermotolerance of S. avenae and M. dirhodum. Significant differences in the behaviour of parasitized and non-parasitized aphids were observed, in addition to differences between host species, and such behaviours are discussed in view of the potential for host manipulation.

  2. Effect of buccolingual inclinations of maxillary canines and premolars on perceived smile attractiveness.

    Science.gov (United States)

    Xu, Hui; Han, Xianglong; Wang, Yanmin; Shu, Rui; Jing, Yan; Tian, Ye; Andrews, Will A; Andrews, Lawrence F; Bai, Ding

    2015-02-01

    In this study, we aimed to investigate the effect of buccolingual inclinations of the maxillary canines and premolars on the perceived attractiveness of the smile when viewed from the frontal perspective. A smiling frontal photograph was taken of a man. A 3-dimensional digital dental model of this subject was constructed within which the buccolingual inclinations of the canines and premolars could be altered relative to the occlusal plane. Three-dimensional models of the altered digital models were then printed in resin and mounted on articulators. Frontal photos of the mounted models were taken and transferred to the smile image. A series of images was produced with the canines and premolars inclined buccally or lingually by different degrees. The smile images were assessed by 2 panels, orthodontists and laypeople. There was a broad range of esthetic acceptability for the buccolingual inclinations of the maxillary canines and premolars. The range of preferred inclinations was not as broad. Smile esthetics was significantly compromised (P <0.01) when the canines were lingually inclined more than -12°, or the premolars were lingually inclined more than -15°, as perceived by orthodontists and laypersons. Buccally tipping the canines more than 6° also made the smile esthetics less satisfying (P <0.01). It could be esthetically satisfying to position the teeth within the ranges of 0° to -7° of inclination for the canines and -3° to -11° of inclination for the premolars, as assessed by the orthodontists, or of 3° to -10° of inclination for the canines and 5° to -11° of inclination for the premolars, as assessed by the laypersons. Clinicians could exercise flexibility within this range, when compromising tooth positions for transverse jaw discrepancies. Copyright © 2015 American Association of Orthodontists. Published by Elsevier Inc. All rights reserved.

  3. Effects of attractiveness and status in dating desire in homosexual and heterosexual men and women

    NARCIS (Netherlands)

    Ha, P.T.; Berg, J.E.M. van den; Engels, R.C.M.E.; Lichtwarck-Aschoff, A.

    2012-01-01

    The present study examined partner preferences of homosexual and heterosexual men and woman, focusing on attractiveness and status. Homosexual (N = 591 men; M age = 28.87 years, SD = 10.21; N = 249 women; M age = 33.36 years, SD = 13.12) and heterosexual participants (N = 346 men; M age = 39.74

  4. Effectiveness of synthetic versus natural human volatiles as attractants for Anopheles gambiae (Diptera: Culicidae) sensu stricto

    NARCIS (Netherlands)

    Smallegange, R.C.; Knols, B.G.J.; Takken, W.

    2010-01-01

    Females of the African malaria vector, Anopheles gambiae Giles sensu stricto, use human volatiles to find their blood-host. Previous work has shown that ammonia, lactic acid, and aliphatic carboxylic acids significantly affect host orientation and attraction of this species, In the current study,

  5. 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)

  6. Effects of Student Race and Physical Attractiveness on Teachers' Judgments of Transgressions.

    Science.gov (United States)

    Marwit, Karen L.; And Others

    1978-01-01

    Student and practicing teachers rated severity of classroom misbehaviors ascribed to Black or White attractive or unattractive children. Following student teaching, ratings of Black children's transgressions increased in severity, and ratings of White children's transgressions remained the same. Practicing teachers were affected by student…

  7. The Effects of Crowding and Interpersonal Attraction on Affective Responses, Task Performance, and Verbal Behavior.

    Science.gov (United States)

    Emiley, Stephen F.

    This report describes two studies in which 48 male college students and 144 male high school students, respectively, were assigned to high or low spatial density conditions and instructed to construct, as a team, an erector set model within a 40-minute period. High school students were assigned to high, middle, and low attraction groups on the…

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

    Science.gov (United States)

    Worchel, Stephen; And Others

    In order to examine the conditions that determine when intergroup cooperation will result in increased intergroup attraction, a group of 494 male and female undergraduate students was divided into task groups consisting of eight to twelve individuals. In the first phase of the study, groups were led to believe that they were either competing,…

  9. Basins of Attraction for Two-Species Competitive Model with Quadratic Terms and the Singular Allee Effect

    Directory of Open Access Journals (Sweden)

    A. Brett

    2015-01-01

    Full Text Available We consider the following system of difference equations: xn+1=xn2/B1xn2+C1yn2, yn+1=yn2/A2+B2xn2+C2yn2,  n=0, 1, …,   where B1, C1, A2, B2, C2 are positive constants and x0, y0≥0 are initial conditions. This system has interesting dynamics and it can have up to seven equilibrium points as well as a singular point at (0,0, which always possesses a basin of attraction. We characterize the basins of attractions of all equilibrium points as well as the singular point at (0,0 and thus describe the global dynamics of this system. Since the singular point at (0,0 always possesses a basin of attraction this system exhibits Allee’s effect.

  10. 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

  11. A Test of Two Competing Explanations for the Attraction-Enhancing Effects of Counselor Self-Disclosure.

    Science.gov (United States)

    Klein, Jill G.; Friedlander, Myrna L.

    1987-01-01

    Tested two theoretical explanations for attraction-enhancing effects of counselor self-disclosure by constructing counseling analogue which varied the valence (positive or negative) of a counselor's disclosure and its relevance to client's presenting problem. Clients were 70 male college students. Results were mixed, supporting social exchange…

  12. On Linking Social Performance with Social Competence: Some Relations between Communicative Style and Attributions of Interpersonal Attractiveness and Effectiveness.

    Science.gov (United States)

    Brandt, David R.

    1979-01-01

    Explores the process of impression formation in initial interactions as a function of a person's communicative style. Develops a method for measurement of interactive or communicative style and describes a study designed to empirically assess relations between style, attractiveness, and effectiveness. (JMF)

  13. Cockroach Oothecal Parasitoid, Evania appendigaster (Hymenoptera: Evaniidae) Exhibits Oviposition Preference Towards Oothecal Age Most Vulnerable to Host Cannibalism.

    Science.gov (United States)

    Tee, Hui-Siang; Lee, Chow-Yang

    2017-09-27

    Many female parasitoid wasps optimize host selection to balance the benefits of high-quality hosts and the costs of predator- or hyperparasitoid-induced mortality risks to maximize their fitness. Cannibalism exists in many insect species and affects survival of parasitoid larvae developing in or on parasitized hosts. However, little is known about how parasitoid wasps resolve the fitness consequence of host cannibalism-induced mortality risk during host selection. We examined the effect of oothecal age on cannibalism in the American cockroach Periplaneta americana (L.) (Dictyoptera: Blattidae) and its effect on host age selection and fitness of its oothecal parasitoid Evania appendigaster (L.) (Hymenoptera: Evaniidae). P. americana differentially cannibalized 1-d-old (30‒60%) versus 10- to 40-d-old oothecae (<9%). However, parasitoid females did not avoid but still preferred to parasitize 1-d-old (45%) over 10- to 40-d-old oothecae (1.6‒20%). The parasitism rate was greater and the handling time was shorter on 1-d-old compared to older oothecae. For parasitoid progeny emerging from different-aged oothecae, regression analysis showed that development time increased and body size (measured as hind tibia length) and longevity decreased with oothecal age. These results demonstrate that reduced parasitoid progeny survival due to host cannibalism did not change the parasitoid's oviposition preference for newly laid oothecae, and that E. appendigaster females traded progeny survival for fitness gains for themselves and their progeny. © The Authors 2017. Published by Oxford University Press on behalf of Entomological Society of America. All rights reserved. For permissions, please email: journals.permissions@oup.com.

  14. 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.

  15. 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".

  16. STRUKTUR KOMUNITAS HYMENOPTERA PARASITOID PADA TUMBUHAN LIAR DI SEKITAR PERTANAMAN PADI DI DAERAH ALIRAN SUNGAI (DAS CIANJUR, JAWA BARAT

    Directory of Open Access Journals (Sweden)

    Yaherwandi, S. Manuwoto, D. Buchori, P. Hidayat, dan L.B. Prasetyo.

    2012-02-01

    Full Text Available Hymenoptera Parasitoid Community Structure on Non-crops Vegetation Around Rice fields in Cianjur Watershed, West Java. Hymenoptera parasitoids have an important role in agroecosystem because of their ability in suppressing pest population. Their presence in the field is seen as the key to agricultural ecosystem. Their presence can be influenced by the availability of non-crop vegetation. Some adult Hymenoptera parasitoids require food in the form of pollen and nectar of wild flowers to ensure effective reproduction and longevity. The objective of this research was to study Hymenoptera parasitoid communities in non-crop vegetation around rice fields at Cianjur Watershed. Samplings were conducted at three different landscape, i.e. Nyalindung, Gasol and Selajambe West Java. Insects were sampled by two trapping techniques (farmcop and sweep net in two lines of transect for each landscape. A total of 257 species from 25 families of Hymenoptera parasitoids were collected in non-crop vegetation at Cianjur Watershed. Landscape structure, flowering vegetation, and pesticide application affected the species richness, diversity and evenness of Hymenoptera parasitoid in non-crop vegetation.

  17. 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

    2015-10-27

    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.

  18. 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.

  19. The effects of sleep debt on risk perception, risk attraction and betting behavior during a blackjack style gambling task.

    Science.gov (United States)

    Frings, Daniel

    2012-09-01

    Gamblers often gamble while experiencing fatigue due to sleep deprivation or cumulative sleep debt. Such fatigue has been shown to make decision makers behave more riskily. The present study aimed to test the role of two cognitive processes, risk perception and risk attraction, in this effect. Two hundred and two participants played twelve hands of a black-jack style card game while either fatigued or reasonably alert. Findings showed that both fatigued and alert participants rated higher risk bets as more risky than lower risk bets, suggesting risk perception was unaffected by fatigue. However, fatigued participants did not rate higher risk bets as less attractive than lower risk bets, and reduced the size of their wager to a lesser extent when objective risk increased. These findings are discussed in relation to the effects of fatigue on motivated tasks and the need for gamblers to be aware of the effects of fatigue.

  20. 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...

  1. Effect of facial rejuvenation surgery on perceived attractiveness, femininity, and personality.

    Science.gov (United States)

    Reilly, Michael J; Tomsic, Jaclyn A; Fernandez, Stephen J; Davison, Steven P

    2015-01-01

    To date, the conversation about facial rejuvenation surgery has focused on one goal: youthfulness. However, human beings are judged throughout life based on many other characteristics and personal qualities conveyed by their faces. The term facial profiling has been used to describe this act of determining personality attributes through visual observation. To introduce the concept of facial profiling to the surgical literature and to evaluate and quantify the changes in personality perception that occur with facial rejuvenation surgery. This study was a retrospective evaluation of preoperative and postoperative photographs of 30 white female patients who underwent facial rejuvenation surgery between January 1, 2009, and December 31, 2013. Procedures included rhytidectomy (face-lift), upper blepharoplasty, lower blepharoplasty, eyebrow-lift, neck-lift, and/or chin implant. The 60 photographs (30 preoperative and 30 postoperative) of these patients were split into 6 groups, each with 5 preoperative and 5 postoperative photographs. The same patient's preoperative and postoperative photographs were not included in any single group to avoid any recall bias. At least 24 individuals rated each photograph for 6 personality traits (aggressiveness, extroversion, likeability, trustworthiness, risk seeking, and social skills), as well as for attractiveness and femininity. The raters were blinded as to the intent of the study. Ratings of personality traits, attractiveness, and femininity. Of the 8 traits that were evaluated, analysis revealed 4 traits with statistically significant improvements when comparing preoperative and postoperative scores: likeability (+0.36, P < .01), social skills (+0.38, P = .01), attractiveness (+0.36, P = .01), and femininity (+0.39, P = .02). Improvement in scores for perceived trustworthiness (+0.22, P = .06), aggressiveness (-0.14, P = .32), extroversion (+0.19, P = .14), and risk seeking (+0.10, P = .27) did not

  2. Effect of Common Species of Florida Landscaping Plants on the Efficacy of Attractive Toxic Sugar Baits Against Aedes albopictus.

    Science.gov (United States)

    Seeger, Kelly E; Scott, Jodi M; Muller, Gunter C; Qualls, Whitney A; Xue, Rui-De

    2017-06-01

    Attractive toxic sugar bait (ATSB) was applied to 5 different types of commonly found plants in landscaping of northeastern Florida. The ATSB applications were assessed for possible plant effects and preference against Aedes albopictus in semifield evaluations. Positive and negative controls consisted of plants sprayed with attractive sugar bait (no toxicant) and plants with nothing applied. Bioassays were conducted on stems with leaf clippings and on full plants to assess any difference in mosquito mortality on the different plants. Plants utilized in these evaluations were Indian hawthorne, Yaupon holly, Japanese privet, Loropetalum ruby, and podocarpus. In both assays, no significant difference was observed in the effect of ATSBs on adult female mosquitoes based on the type of plant. ATSB could be applied to common landscape plants for adult Ae. albopictus control.

  3. Existential neuroscience: effects of mortality salience on the neurocognitive processing of attractive opposite-sex faces.

    Science.gov (United States)

    Silveira, Sarita; Graupmann, Verena; Agthe, Maria; Gutyrchik, Evgeny; Blautzik, Janusch; Demirçapa, Idil; Berndt, Andrea; Pöppel, Ernst; Frey, Dieter; Reiser, Maximilian; Hennig-Fast, Kristina

    2014-10-01

    Being reminded of the inherently finite nature of human existence has been demonstrated to elicit strivings for sexual reproduction and the formation and maintenance of intimate relationships. Recently, it has been proposed that the perception of potential mating partners is influenced by mortality salience. Using functional magnetic resonance imaging, we investigated the neurocognitive processing of attractive opposite-sex faces after priming with death-related words for heterosexual men and women. Significant modulations of behavioral and neural responses were found when participants were requested to decide whether they would like to meet the presented person. Men were more in favor of meeting attractive women after being primed with death-related words compared to a no-prime condition. Increased neural activation could be found under mortality salience in the left anterior insula and the adjacent lateral prefrontal cortex (lPFC) for both men and women. As previously suggested, we believe that the lPFC activation reflects an approach-motivated defense mechanism to overcome concerns that are induced by being reminded of death and dying. Our results provide insight on a neurocognitive level that approach motivation in general, and mating motivation in particular is modulated by mortality salience. © The Author (2013). Published by Oxford University Press. For Permissions, please email: journals.permissions@oup.com.

  4. Variation in natural plant products and the attraction of bodyguards involved in indirect plant defense

    NARCIS (Netherlands)

    Mumm, R.; Dicke, M.

    2010-01-01

    Plants can respond to feeding or egg deposition by herbivorous arthropods by changing the volatile blend that they emit. These herbivore-induced plant volatiles (HIPVs) can attract carnivorous natural enemies of the herbivores, such as parasitoids and predators, a phenomenon that is called indirect

  5. 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)

  6. A trade-off between diapause duration and fitness in female parasitoids.

    NARCIS (Netherlands)

    Ellers, J.; van Alphen, J.J.M.

    2002-01-01

    1. Diapause allows insects to cope with adverse weather conditions but also poses substantial fitness costs, e,g. through reduced survival of the diapausing stage or sublethal effects in the following season. 2. The energetic costs of diapause in females of the parasitoid Asobara tabida Nees

  7. Warming and nitrogen affect size structuring and density dependence in a host–parasitoid food web

    Science.gov (United States)

    de Sassi, Claudio; Staniczenko, Phillip P. A.; Tylianakis, Jason M.

    2012-01-01

    Body size is a major factor constraining the trophic structure and functioning of ecological communities. Food webs are known to respond to changes in basal resource abundance, and climate change can initiate compounding bottom-up effects on food-web structure through altered resource availability and quality. However, the effects of climate and co-occurring global changes, such as nitrogen deposition, on the density and size relationships between resources and consumers are unknown, particularly in host–parasitoid food webs, where size structuring is less apparent. We use a Bayesian modelling approach to explore the role of consumer and resource density and body size on host–parasitoid food webs assembled from a field experiment with factorial warming and nitrogen treatments. We show that the treatments increased resource (host) availability and quality (size), leading to measureable changes in parasitoid feeding behaviour. Parasitoids interacted less evenly within their host range and increasingly focused on abundant and high-quality (i.e. larger) hosts. In summary, we present evidence that climate-mediated bottom-up effects can significantly alter food-web structure through both density- and trait-mediated effects. PMID:23007092

  8. Sexual size and development time dimorphism in a parasitoid wasp: an exception to the rule?

    NARCIS (Netherlands)

    Harvey, J.A.; Strand, M.R.

    2003-01-01

    Sexual dimorphisms in adult size (SSD) and development time (SDTD) occur in many groups of organisms. In insects, some of the best examples occur in parasitoid wasps where most studies report that females are larger than males but take longer to develop. Sex-specific differences in the effects of

  9. 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.

  10. Stress-reducing effects of indoor plants in the built healthcare environment: the mediating role of perceived attractiveness.

    Science.gov (United States)

    Dijkstra, K; Pieterse, M E; Pruyn, A

    2008-09-01

    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 because such an environment is perceived as being more attractive. A single-factor between-subjects experimental design (nature: indoor plants vs. no plants) was used in which participants (n=77) were presented with a scenario describing hospitalization with a possible legionella diagnosis. The study was conducted from March to May 2007 in the Netherlands. Subsequently, they were exposed to a photo of a hospital room. In this room were either indoor plants, or there was a painting of an urban environment on the wall. Afterwards, perceived stress and the perceived attractiveness of the hospital room were measured. Participants exposed to the hospital room with indoor plants reported less stress than those in the control condition. Mediation analysis confirmed that indoor plants in a hospital room reduce feelings of stress through the perceived attractiveness of the room. This study confirms the stress-reducing properties of natural elements in the built healthcare environment. It also sheds light on the underlying mechanism causing this stress-reduction.

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

    Science.gov (United States)

    Pankratow, Melanie; Berry, Tanya R; McHugh, Tara-Leigh F

    2013-01-01

    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. 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). Participants read a health, appearance, or control article, listed thoughts, and completed questionnaires measuring reasons for exercising, physical self-perception, and exercise self-identity. 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. 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.

  12. 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.

  13. Cross-protection experiments with parasitoids in the genus Microplitis (Hymenoptera: Braconidae) suggest a high level of specificity in their associated bracoviruses

    NARCIS (Netherlands)

    Kadash, K.; Harvey, J.A.; Strand, M.R.

    2003-01-01

    The immunological and developmental effects of bracoviruses (BVs) from three parasitoids in the genus Microplitis (Braconidae: Microgastrinae) were compared in the hosts Pseudoplusia includens and Heliothis virescens (Lepidoptera: Noctuidae). Southern blotting experiments indicated that viral DNAs

  14. Effects of the Reciprocity of Self-Disclosure upon Attribution of Attractive Qualities to the Ingratiation Target.

    Science.gov (United States)

    1981-01-01

    validated and researched attraction scale was produced by Byrne ( 1971 ). The most widely accepted theoretical explanation of interpersonal attraction is... Interpersonal attraction has been defined as a posi- tive attitude toward another individual (Berscheid Walster, 1978). According to Berscheid and Walster’s re...provide another. According to many sources which advise on improving interpersonal attraction , one who wishes to be attractive F should first indicate

  15. Niche comparison among two invasive leafminer species and their parasitoid Opius biroi: implications for competitive displacement.

    Science.gov (United States)

    Xing, Zhenlong; Zhang, Linya; Wu, Shengyong; Yi, Hao; Gao, Yulin; Lei, Zhongren

    2017-06-26

    Fundamental to competitive displacement in biological invasion is that exotic species occupy the ecological niches of native species in novel environments. Contrasting outcomes of competitive displacement have occurred between Liriomyza trifolii and L. sativae in different geographical regions following their introduction. Various factors have been advanced in an attempt to explain these different competitive outcomes, although none of these explanations have addressed the effects of niche differences. We conducted field cage experiments to compare the feeding and habitat niches of the two leafminer species and their primary parasitoid, Opius biroi, when occurring together on kidney bean. A wider spatiotemporal niche breadth was found in L. trifolii (0.3670) than in L. sativae (0.3496). With respect to the parasitoid, the proportional niche similarity between L. sativae and the parasitoid was 0.3936 but only 0.0835 for L. trifolii, while similar results were found for niche overlap, indicating that stronger trailing behaviour and parasitic effects of O. biroi occurred in L. sativae. In conclusion, L. trifolii has outperformed L. sativae in occupying the ecological niche and is superior to L. sativae in avoiding parasitization by the pupal parasitoid, O. biroi.

  16. Effects of release rates on the range of attraction of carbon dioxide to some southwestern Ontario mosquito species.

    Science.gov (United States)

    McIver, S B; McElligott, P E

    1989-03-01

    The effects of release rates of 0, 250, 500, 1,000 and 4,000 ml/min on the range of attraction of carbon dioxide to some southwestern Ontario mosquito species was determined using ramp traps placed at 3, 7, 11, 15 and 19 m from a central pressurized cylinder. For female Aedes vexans, spring Aedes spp. and Anopheles walkeri, an increase in the release rate of CO2 from 1,000 to 4,000 ml/min resulted in extension of the range of attractiveness from between 3-7 m to between 7-11 m; rates of 500 and 250 ml/min did result in an increase in number of mosquitoes in the traps. Correspondingly, significantly more mosquitoes were caught in the traps at 3 m when the rate was increased to 1,000 ml/min from 500 ml/min. For Ae. vexans, 4,000 ml/min of CO2 attracted more mosquitoes to the 7 m traps than 1,000 ml/min. In this work carbon dioxide did not result in an increase in the number of Culiseta inornata, Cs. morsitans and Culex restuans and Cx. pipiens in the traps.

  17. 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.

  18. Psychobiology of facial attractiveness.

    Science.gov (United States)

    Cellerino, A

    2003-01-01

    The last decade has witnessed an upsurge of interest in the research on facial attractiveness. The development of computer graphics has allowed to objectively investigate the conserved features of attractive faces. Averageness, symmetry and sex-specific traits have been associated with attractiveness. The effect of averageness is exemplified by blending a set of real faces into a chimeric face. This composite is more attractive than most of the faces used to create it. Beautiful faces are not simply average faces, however. If the female-specific features of a female composite face are enhanced, the resulting face is perceived as more attractive than the composite. In particular, smaller than average chin, smaller than average nose and higher than average forehead, all are traits associated with female's attractiveness. These traits have been interpreted as signs of high estrogen/testosterone ratio and therefore cues of high fertility. However, these same traits are also a species-specific characteristic of Homo sapiens that differentiates it from other hominid species. Preference for caricature of human features could represent a relic of species recognition mechanisms. Female preferences for male faces proved to be more variable than male preferences for female faces. Different facial traits are preferred in the choice of short-term and long-term partners. Preference for short term depend on the hormonal status and changes across the menstrual cycle and is influenced by contraceptive hormonal treatment. Psychological factors are also important sources of variance: female preferences correlate with self-perceived attractiveness, status in a relationship and degree of gender-conformity.

  19. 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.

  20. In situ Occurrence, Prevalence and Dynamics of Parvilucifera Parasitoids during Recurrent Blooms of the Toxic Dinoflagellate Alexandrium minutum

    Directory of Open Access Journals (Sweden)

    Elisabet Alacid

    2017-08-01

    Full Text Available Dinoflagellate blooms are natural phenomena that often occur in coastal areas, which in addition to their large number of nutrient-rich sites are characterized by highly restricted hydrodynamics within bays, marinas, enclosed beaches, and harbors. In these areas, massive proliferations of dinoflagellates have harmful effects on humans and the ecosystem. However, the high cell density reached during blooms make them vulnerable to parasitic infections. Under laboratory conditions parasitoids are able to exterminate an entire host population. In nature, Parvilucifera parasitoids infect the toxic dinoflagellate Alexandrium minutum during bloom conditions but their prevalence and impact remain unexplored. In this study, we evaluated the in situ occurrence, prevalence, and dynamics of Parvilucifera parasitoids during recurrent blooms of A. minutum in a confined site in the NW Mediterranean Sea as well as the contribution of parasitism to bloom termination. Parvilucifera parasitoids were recurrently detected from 2009 to 2013, during seasonal outbreaks of A. minutum. Parasitic infections in surface waters occurred after the abundance of A. minutum reached 104–105 cells L−1, suggesting a density threshold beyond which Parvilucifera transmission is enhanced and the number of infected cells increases. Moreover, host and parasitoid abundances were not in phase. Instead, there was a lag between maximum A. minutum and Parvilucifera densities, indicative of a delayed density-dependent response of the parasitoid to host abundances, similar to the temporal dynamics of predator-prey interactions. The highest parasitoid prevalence was reached after a peak in host abundance and coincided with the decay phase of the bloom, when a maximum of 38% of the A. minutum population was infected. According to our estimates, Parvilucifera infections accounted for 5–18% of the total observed A. minutum mortality, which suggested that the contribution of parasitism to

  1. Attracting International Hotels

    DEFF Research Database (Denmark)

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

    2015-01-01

    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...... 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...... 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. 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. Climate variation alters the synchrony of host–parasitoid interactions

    National Research Council Canada - National Science Library

    Wetherington, Miles T; Jennings, David E; Shrewsbury, Paula M; Duan, Jian J

    2017-01-01

    .... Although some research has examined how parasitoids will respond to colder temperatures or experimental warming, we know relatively little about how increased variation in temperature and humidity...

  4. Effect of attractive interactions between polymers on the effective force acting between colloids immersed in a polymer system: Analytic liquid-state theory.

    Science.gov (United States)

    Chervanyov, A I

    2016-12-28

    By making use of the polymer reference interaction site model, we analytically study the effect of attractive interactions between polymers on the effective forces acting between colloids immersed in a polymer system. The performed theoretical analysis has no restrictions with respect to the polymer density and relative sizes of the colloids and polymers. The polymer mediated (PM) potential acting between colloids is shown to significantly depend on the strength and range of the polymer-polymer interactions. In the nano-particle limit, where the colloid radius is much smaller than the polymer gyration radius, the presence of attractive polymer-polymer interactions causes only quantitative changes to the PM potential. In the opposite limit of relatively large colloids, the polymer-polymer interactions revert the sign of the total effective force acting between colloids so that this force becomes attractive at sufficiently large polymer densities. With the objective to study an intricate interplay between the attractive PM forces and steric repulsion in different polymer density regimes, we calculate the second virial coefficient B of the total effective potential acting between colloids. The dependence of B on the polymer density is discussed in detail, revealing several novel features of the PM interactions caused by the presence of attractive polymer-polymer interactions.

  5. Survival and development of a stored-product pest, Sitophilus zeamais (Coleoptera: Curculionidae), and its natural enemy, the parasitoid Lariophagus distinguendus (Hymenoptera: Pteromalidae), on transgenic Bt maize.

    Science.gov (United States)

    Hansen, Lise S; Lövei, Gábor L; Székács, András

    2013-05-01

    The effect of transgenic maize (Zea mays L.) containing a lepidopteran-specific Bt toxin on a stored-product pest, Sitophilus zeamais Motschulsky, and its parasitoid, Lariophagus distinguendus Förster, was examined in the laboratory to test the impact of transgenic maize on stored-product pests and their biological control. Weevils were not harmfully affected by transgenic Bt maize in their development characteristics (development time, body mass), and females emerging from transgenic maize kernels were larger. However, significantly fewer parasitoid females emerged from weevils that developed in transgenic kernels, although parasitoids did not develop more slowly and were not different in size or mass from their conspecifics emerging from hosts in non-transgenic maize kernels. The emergence of female parasitoids was reduced in transgenic Bt maize, and this effect cannot be explained by the known lepidopteran-specific toxicity of Bt Cry1Ab toxin. © 2012 Society of Chemical Industry.

  6. Larval RNAi in Nasonia (parasitoid wasp).

    Science.gov (United States)

    Werren, John H; Loehlin, David W; Giebel, Jonathan D

    2009-10-01

    Nasonia is a complex of four closely related species of wasps with several features that make it an excellent system for a variety of genetic studies. These include a short generation time, ease of rearing, interfertile species, visible and molecular markers, and a sequenced genome. Furthermore, its parasitoid lifestyle allows investigations of questions relating to parasitoid/host dynamics, host preference, and specialist versus generalist biology. It also can serve as a behavior model for studies of courtship, male aggression and territoriality, female dispersal, and sex ratio control. This protocol describes a method to use RNA interference (RNAi) to knock down genes in Nasonia larvae. Unlike in Drosophila, RNAi in Nasonia is systemic. In the example presented here, adult red-eye-color phenotypes are produced by injecting double-stranded RNA (dsRNA) against the eye color gene cinnabar into last-instar Nasonia larvae.

  7. Analisis senyawa volatil dari ekstrak tanaman yang berpotensi sebagai atraktan parasitoid telur wereng batang coklat, Anagrus nilaparvatae (Pang et Wang (Hymenoptera: Mymaridae

    Directory of Open Access Journals (Sweden)

    Surjani Wonorahardjo

    2015-09-01

    Full Text Available Plants produce volatiles as communication cues intra- or inter- species. Infested plants by herbivores will produce volatiles as indirect defense mechanism that attracts natural enemies of herbivores. Analysis of volatiles compounds produced by rice plant as result of infested brown plant hopper (BPH, Nilaparvata lugens Stâl, was done to identify compounds in the volatiles that potentially can be used as attractant for egg parasitoids of BPH, Anagrus nilaparvatae (Pang et Wang (Hymenoptera: Mymaridae. This research was an early stage to develop formulation of parasitoid attractant. The research activities include volatiles extraction of infested rice stem by BPH eggs using acetone, n-hexane as the extraction solvents; analyses of volatile compounds with GC-MS; and bioassay of parasitoid orientation behavior to the volatiles using olfactometer methods. Extraction methods applied were maceration and continuous extraction followed by concentration. Bioassay on the parasitoid orientation behavior was done by using Y-tube olfactometer and every lot of bioassay using 30 parasitoid females with 3 replicates. The results showed that the volatile compounds of extract of infested rice stem by BPH eggs comprise of 16 components. The highest proportion of the components extracted with acetone is 2-Pentanone, 4-hydroxy-4-methyl (19,9%, while those with n-hexane is Hexanedioic acid, dioctyl ester (65%. A. nilaparvatae showed positive response to the volatiles extracted from infested rice plant by N. lugens eggs. Therefore, the volatiles can be used as an attractant for the egg A. nilaparvatae to support rice pest management.

  8. Teasing apart the effect of visibility and physical co-presence to examine the effect of CMC on interpersonal attraction

    NARCIS (Netherlands)

    Croes, Emmelyn; Antheunis, Marjolijn; Schouten, Alexander; Krahmer, Emiel

    2016-01-01

    This study analyzed the possible difference in interpersonal attraction between communicators in cue-rich computer-mediated communication (CMC) and face-to-face (FtF) communication. The first aim was to determine whether physical co-presence and visibility may account for differences in

  9. 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.

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

    Directory of Open Access Journals (Sweden)

    Megan V Herlihy

    Full Text Available 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.

  11. Theoretical modeling of the effect of Casimir attraction on the electrostatic instability of nanowire-fabricated actuators

    Science.gov (United States)

    Mokhtari, J.; Farrokhabadi, A.; Rach, R.; Abadyan, M.

    2015-04-01

    The presence of the quantum vacuum fluctuations, i.e. the Casimir attraction, can strongly affect the performance of ultra-small actuators. The strength of the Casimir force is significantly influenced by the geometries of interacting bodies. Previous research has exclusively studied the impact of the vacuum fluctuations on the instability of nanoactuators with planar geometries. However, no work has yet considered this phenomenon in actuators fabricated from nanowires/nanotubes with cylindrical geometries. In our present work, the influence of the Casimir attraction on the electrostatic stability of nanoactuators fabricated from cylindrical conductive nanowire/nanotube is investigated. The Dirichlet mode is considered and an asymptotic solution, based on scattering theory, is applied to consider the effect of vacuum fluctuations in the theoretical model. The size-dependent modified couple stress theory is employed to derive the constitutive equation of the actuator. The governing nonlinear equations are solved by two different approaches, i.e. the finite difference method and modified Adomian-Padé method. Various aspects of the problem, i.e. comparison with the van der Waals force regime, the variation of instability parameters, effect of geometry and coupling between the Casimir force and size dependency are discussed. This work is beneficial to determine the impact of Casimir force on nanowire/nanotube-fabricated actuators.

  12. When mothers make sons sexy: maternal effects contribute to the increased sexual attractiveness of extra-pair offspring.

    Science.gov (United States)

    Tschirren, Barbara; Postma, Erik; Rutstein, Alison N; Griffith, Simon C

    2012-03-22

    Quality differences between offspring sired by the social and by an extra-pair partner are usually assumed to have a genetic basis, reflecting genetic benefits of female extra-pair mate choice. In the zebra finch (Taeniopygia guttata), we identified a colour ornament that is under sexual selection and appears to have a heritable basis. Hence, by engaging in extra-pair copulations with highly ornamented males, females could, in theory, obtain genes for increased offspring attractiveness. Indeed, sons sired by extra-pair partners had larger ornaments, seemingly supporting the genetic benefit hypothesis. Yet, when comparing ornament size of the social and extra-pair partners, there was no difference. Hence, the observed differences most likely had an environmental basis, mediated, for example, via differential maternal investment of resources into the eggs fertilized by extra-pair and social partners. Such maternal effects may (at least partly) be mediated by egg size, which we found to be associated with mean ornament expression in sons. Our results are consistent with the idea that maternal effects can shape sexual selection by altering the genotype-phenotype relationship for ornamentation. They also caution against automatically attributing greater offspring attractiveness or viability to an extra-pair mate's superior genetic quality, as without controlling for differential maternal investment we may significantly overestimate the role of genetic benefits in the evolution of extra-pair mating behaviour.

  13. Fitness trade-off in peach-potato aphids (Myzus persicae) between insecticide resistance and vulnerability to parasitoid attack at several spatial scales.

    Science.gov (United States)

    Foster, S P; Denholm, I; Poppy, G M; Thompson, R; Powell, W

    2011-12-01

    Insecticide-resistant clones of the peach-potato aphid, Myzus persicae (Sulzer), have previously been shown to have a reduced response to aphid alarm pheromone compared to susceptible ones. The resulting vulnerability of susceptible and resistant aphids to attack by the primary endoparasitoid, Diaeretiella rapae (McIntosh), was investigated across three spatial scales. These scales ranged from aphids confined on individual leaves exposed to single female parasitoids, to aphids on groups of whole plants exposed to several parasitoids. In all experiments, significantly fewer aphids from insecticide-susceptible clones became parasitised compared to insecticide-resistant aphids. Investigations of aphid movement showed at the largest spatial scale that more susceptible aphids than resistant aphids moved from their inoculation leaves to other leaves on the same plant after exposure to parasitoids. The findings imply that parasitoids, and possibly other natural enemies, can influence the evolution and dynamics of insecticide resistance through pleiotropic effects of resistance genes on important behavioural traits.

  14. Two Gut-Associated Yeasts in a Tephritid Fruit Fly have Contrasting Effects on Adult Attraction and Larval Survival.

    Science.gov (United States)

    Piper, Alexander M; Farnier, Kevin; Linder, Tomas; Speight, Robert; Cunningham, John Paul

    2017-09-01

    Yeast-insect interactions have been well characterized in drosophilid flies, but not in tephritid fruit flies, which include many highly polyphagous pest species that attack ripening fruits. Using the Queensland fruit fly (Bactrocera tryoni) as our model tephritid species, we identified yeast species present in the gut of wild-collected larvae and found two genera, Hanseniaspora and Pichia, were the dominant isolates. In behavioural trials using adult female B. tryoni, a fruit-agar substrate inoculated with Pichia kluyveri resulted in odour emissions that increased the attraction of flies, whereas inoculation with Hanseniaspora uvarum, produced odours that strongly deterred flies, and both yeasts led to decreased oviposition. Larval development trials showed that the fruit-agar substrate inoculated with the 'deterrent odour' yeast species, H. uvarum, resulted in significantly faster larval development and a greater number of adult flies, compared to a substrate inoculated with the 'attractive odour' yeast species, P. kluyveri, and a yeast free control substrate. GC-MS analysis of volatiles emitted by H. uvarum and P. kluyveri inoculated substrates revealed significant quantitative differences in ethyl-, isoamyl-, isobutyl-, and phenethyl- acetates, which may be responsible for the yeast-specific olfactory responses of adult flies. We discuss how our seemingly counterintuitive finding that female B. tryoni flies avoid a beneficial yeast fits well with our understanding of female choice of oviposition sites, and how the contrasting behavioural effects of H. uvarum and P. kluyveri raises interesting questions regarding the role of yeast-specific volatiles as cues to insect vectors. A better understanding of yeast-tephritid interactions could assist in the future management of tephritid fruit fly pests through the formulation of new "attract and kill" lures, and the development of probiotics for mass rearing of insects in sterile insect control programs.

  15. The Effects of Computer-Aided Antero-Posterior Forehead Movement on Ratings of Facial Attractiveness

    Science.gov (United States)

    2015-06-01

    8217!]. Angle Orthodontist , 80(4), 490-496. doi: 10.2319/052207-243.1 Schlosser, J.B., Preston, C.B., & Lampasso, J. (2005). The effects of computer...posterior 4. CITI, Collaborative Institutional Training Initiative 5. FA, Facial-Axis 6. FMIA, Frankfort-Mandibular Incisor Angle 7. GALL, Goal Anterior...Effects of hard tissue manipulation on facial profile and overlying soft tissue In severe cases of malocclusion orthodontists and oral surgeons

  16. Trichogramma pretiosum attraction due to the Elasmopalpus lignosellus damage in maize

    Directory of Open Access Journals (Sweden)

    Luciane Modenez Saldivar Xavier

    2011-06-01

    Full Text Available The objective of this work was to evaluate if corn plants damaged by the lesser cornstalk borer (Elasmopalpus lignosellus larvae release volatile organic compounds capable of attracting the egg parasitoid Trichogramma pretiosum. The treatments consisted of plants subjected to harm caused by E. lignosellus larvae, plants subjected to mechanical damage, and undamaged plants. The parasitoid was more attracted by the volatiles released by the insect damaged plants than to those released by undamaged corn plants, after 24 and 72 hours. The volatiles (Z-3-hexenyl acetate, β-pinene, β-myrcene, (E-4,8-dimethylnona-1,3,7-triene, and benzothiazole were released in significantly larger quantities by damaged plants. Volatiles released by corn plants damaged by E. lignosellus larvae may act as an indirect defense, attracting by T. pretiosum.

  17. What is beautiful brings out what is good in you: The effect of facial attractiveness on individuals' honesty.

    Science.gov (United States)

    Wang, Jing; Xia, Tiansheng; Xu, Liling; Ru, Taotao; Mo, Ce; Wang, Ting Ting; Mo, Lei

    2017-06-01

    This study tested whether the presence of an attractive face would influence individuals' honesty. In 2 experiments, 225 participants were asked to predict the outcome of computerised coin-flips and to self-report the accuracy of their predictions. Self-reports were made in the presence of a facial photo of a female who had been rated before the experiment as high attractive, middle attractive or low attractive by other volunteers. Participants were rewarded based on their self-reported (not actual) accuracy. The results showed that subjects tended to give more dishonest self-reports when presented with middle or low attractive facial images than when presented with high attractive images, with self-reported accuracy being significantly higher than the random level. The results of this study show that presented with an attractive face, subjects tend to engage in behaviours that conform to moral codes. © 2015 International Union of Psychological Science.

  18. 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.

  19. The Effect of Certain Factors on FDI Attraction - A cross-country analysis

    OpenAIRE

    Giavidou, Maria

    2016-01-01

    In this Master Dissertation we examine the effects of (i) the direct taxes to GDP ratio, of (ii) the nominal unit labor cost, and of (iii) the business cycle fluctuations on the FDI net inflows, for the 19 Euro Area member states between 1999 and 2014. We estimated with Fixed and Random Effects three equations: one for the level of FDI net inflows, one for the first differences at current time and with one period , and one only with lagged differences – model (III). Business cycle was proxied...

  20. Importance of host feeding for parasitoids that attack honeydew-producing hosts

    NARCIS (Netherlands)

    Burger, J.S.M.; Kormany, A.; Van Lenteren, J.C.; Vet, L.E.M.

    2005-01-01

    Insect parasitoids lay their eggs in arthropods. Some parasitoid species not only use their arthropod host for oviposition but also for feeding. Host feeding provides nutrients to the adult female parasitoid. However, in many species, host feeding destroys an opportunity to oviposit. For parasitoids

  1. Facial Cosmetics and Attractiveness: Comparing the Effect Sizes of Professionally-Applied Cosmetics and Identity

    National Research Council Canada - National Science Library

    Jones, Alex L; Kramer, Robin S. S

    2016-01-01

    ... by the global cosmetics industry which is worth billions of pounds [5]. Women report using cosmetics for a variety of reasons, ranging from anxiety about facial appearance, conformity to social norms, and public self-consciousness [6-8], through to appearing more sociable and assertive to others [6]. Cosmetics are effective at improving social perceptions that...

  2. Testing Two Theoretical Explanations for the Attraction-Enhancing Effects of Self-Disclosure.

    Science.gov (United States)

    Ellingson, Kari Trexler; Galassi, John P.

    1995-01-01

    Investigated differential ability of similarity theory and social exchange theory to predict the effects of self-disclosure in a counseling versus a friendship encounter (n=80 undergraduates). Participants rated the videotaped self-disclosure of an individual in an initial dyadic encounter. Unequivocal support was not obtained for either theory.…

  3. Resource acquisition, allocation, and utilization in parasitoid reproductive strategies

    NARCIS (Netherlands)

    Jervis, M.A.; Ellers, J.; Harvey, J.A.

    2008-01-01

    Parasitoids display remarkable inter- and intraspecific variation in their reproductive and associated traits. Adaptive explanations have been proposed for many of the between-trait relationships. We present an overview of the current knowledge of parasitoid reproductive biology, focusing on egg

  4. Climate variation alters the synchrony of host–parasitoid interactions

    Science.gov (United States)

    Although some research has examined how parasitoids will respond to colder temperatures or experimental warming, we know relatively little about how increased variation in temperature could affect interactions between parasitoids and their hosts. Using a study system consisting of emerald ash borer...

  5. Foraging behaviour of parasitoids in multi-herbivore communities

    NARCIS (Netherlands)

    Rijk, de M.

    2016-01-01

    Foraging behaviour of parasitoids in multi-herbivore communities Parasitic wasps, or parasitoids, use herbivore-induced plant volatiles and infochemicals produced directly by the herbivore to locate their herbivorous hosts. This process could be interrupted by the presence of

  6. 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.

  7. 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.

  8. Inverting Steric Effects: Using "Attractive" Noncovalent Interactions To Direct Silver-Catalyzed Nitrene Transfer.

    Science.gov (United States)

    Huang, Minxue; Yang, Tzuhsiung; Paretsky, Jonathan D; Berry, John F; Schomaker, Jennifer M

    2017-12-06

    Nitrene transfer (NT) reactions represent powerful and direct methods to convert C-H bonds into amine groups that are prevalent in many commodity chemicals and pharmaceuticals. The importance of the C-N bond has stimulated the development of numerous transition-metal complexes to effect chemo-, regio-, and diastereoselective NT. An ongoing challenge is to understand how subtle interactions between catalyst and substrate influence the site-selectivity of the C-H amination event. In this work, we explore the underlying reasons why Ag(tpa)OTf (tpa = tris(pyridylmethyl)amine) prefers to activate α-conjugated C-H bonds over 3° alkyl C(sp3)-H bonds and apply these insights to reaction optimization and catalyst design. Experimental results suggest possible roles of noncovalent interactions (NCIs) in directing the NT; computational studies support the involvement of π···π and Ag···π interactions between catalyst and substrate, primarily by lowering the energy of the directed transition state and reaction conformers. A simple Hess's law relationship can be employed to predict selectivities for new substrates containing competing NCIs. The insights presented herein are poised to inspire the design of other catalyst-controlled C-H functionalization reactions.

  9. 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.

  10. An exploratory study of the effects of teacher attractiveness on undergraduates' perceptions of teacher-student sexual involvement.

    Science.gov (United States)

    Fromuth, Mary Ellen; Kelly, David B; Wilson, Amy K; Finch, Lanjericha V; Scruggs, Lindsey

    2013-01-01

    This study explored whether the attractiveness of a teacher affected perceptions of teacher sexual misconduct. Respondents (120 female and 108 male undergraduates) read scenarios depicting teacher sexual misconduct varied by gender dyad (male teacher-female student and female teacher-male student) and two levels of attractiveness (very attractive or ordinary looking). The attractiveness of the teacher had little impact on respondents' perceptions. Significant interactions emerged on most variables between respondent gender and gender dyad. Specifically, male respondents tended to view the female teacher-male student dyad as less negative than the male teacher-female student dyad. Female respondents generally did not make a distinction based on the gender dyad.

  11. A Game of Russian Roulette for a Generalist Dinoflagellate Parasitoid: Host Susceptibility Is the Key to Success.

    Science.gov (United States)

    Alacid, Elisabet; Park, Myung G; Turon, Marta; Petrou, Katherina; Garcés, Esther

    2016-01-01

    Marine microbial interactions involving eukaryotes and their parasites play an important role in shaping the structure of phytoplankton communities. These interactions may alter population densities of the main host, which in turn may have consequences for the other concurrent species. The effect generalist parasitoids exert on a community is strongly dependent on the degree of host specificity. Parvilucifera sinerae is a generalist parasitoid able to infect a wide range of dinoflagellates, including toxic-bloom-forming species. A density-dependent chemical cue has been identified as the trigger for the activation of the infective stage. Together these traits make Parvilucifera-dinoflagellate hosts a good model to investigate the degree of specificity of a generalist parasitoid, and the potential effects that it could have at the community level. Here, we present for the first time, the strategy by which a generalist dinoflagellate parasitoid seeks out its host and determine whether it exhibits host preferences, highlighting key factors in determining infection. Our results demonstrate that in its infective stage, P. sinerae is able to sense potential hosts, but does not actively select among them. Instead, the parasitoids contact the host at random, governed by the encounter probability rate and once encountered, the chance to penetrate inside the host cell and develop the infection strongly depends on the degree of host susceptibility. As such, their strategy for persistence is more of a game of Russian roulette, where the chance of survival is dependent on the susceptibility of the host. Our study identifies P. sinerae as a potential key player in community ecology, where in mixed dinoflagellate communities consisting of hosts that are highly susceptible to infection, parasitoid preferences may mediate coexistence between host species, reducing the dominance of the superior competitor. Alternatively, it may increase competition, leading to species exclusion. If

  12. A game of Russian roulette for a generalist dinoflagellate parasitoid: host susceptibility is the key to success

    Directory of Open Access Journals (Sweden)

    Elisabet eAlacid

    2016-05-01

    Full Text Available Marine microbial interactions involving eukaryotes and their parasites play an important role in shaping the structure of phytoplankton communities. These interactions may alter population densities of the main host, which in turn may have consequences for the other concurrent species. The effect generalist parasitoids exert on a community is strongly dependent on the degree of host specificity. Parvilucifera sinerae is a generalist parasitoid able to infect a wide range of dinoflagellates, including toxic-bloom-forming species. A density-dependent chemical cue has been identified as the trigger for the activation of the infective stage. Together these traits make Parvilucifera-dinoflagellate hosts a good model to investigate the degree of specificity of a generalist parasitoid, and the potential effects that it could have at the community level. Here, we present for the first time, the strategy by which a generalist dinoflagellate parasitoid seeks out its host and determine whether it exhibits host preferences, highlighting key factors in determining infection. Our results demonstrate that in its infective stage, P. sinerae is able to sense potential hosts, but does not actively select among them. Instead, the parasitoids contact the host at random, governed by the encounter probability rate and once encountered, the chance to penetrate inside the host cell and develop the infection strongly depends on the degree of host susceptibility. As such, their strategy for persistence is more of a game of Russian roulette, where the chance of survival is dependent on the susceptibility of the host. Our study identifies P. sinerae as a potential key player in bloom community ecology, where in mixed dinoflagellate communities consisting of hosts that are highly susceptible to infection, parasitoid preferences may mediate coexistence between host species, reducing the dominance of the superior competitor. Alternatively, it may increase competition, leading

  13. Indoor use of attractive toxic sugar bait (ATSB) to effectively control malaria vectors in Mali, West Africa.

    Science.gov (United States)

    Qualls, Whitney A; Müller, Günter C; Traore, Sekou F; Traore, Mohamed M; Arheart, Kristopher L; Doumbia, Seydou; Schlein, Yosef; Kravchenko, Vasiliy D; Xue, Rui-De; Beier, John C

    2015-08-05

    Attractive toxic sugar bait (ATSB) solutions containing any gut toxins can be either sprayed on plants or used in simple bait stations to attract and kill sugar-feeding female and male mosquitoes. This field study in Mali demonstrates the effect of ATSB bait stations inside houses as a vector control method that targets and kills endophilic African malaria vectors. The studies were conducted in five villages located near the River Niger, Mali. Baseline village-wide assessments of densities for female and male Anopheles gambiae sensu lato were performed by pyrethrum spray collections (PSC) in ten houses in each of five villages. To determine the rate of mosquito feeding on bait stations, one bait station per house containing attractive sugar bait (ASB) (without toxin) plus a food dye marker, was set up in ten houses in each of the five villages. PSC collections were conducted on the following day and the percentage of female and male mosquitoes that had fed was determined by visual inspection for the dye marker. Then, a 50-day field trial was done. In an experimental village, one bait station containing ATSB (1% boric acid active ingredient) was placed per bedroom (58 bedrooms), and indoor densities of female and male An. gambiae s.l. were subsequently determined by PSC, and female mosquitoes were age graded. In the five villages, the percentages of An. gambiae s.l. feeding inside houses on the non-toxic bait stations ranged from 28.3 to 53.1% for females and 36.9 to 78.3% for males. Following ATSB indoor bait station presentation, there was a significant reduction, 90% in female and 93% in male populations, of An. gambiae s.l. at the experimental village. A 3.8-fold decrease in the proportion of females that had undergone four or more gonotrophic cycles was recorded at the experimental village, compared to a 1.2-fold increase at the control village. The field trial demonstrates that An. gambiae s.l. feed readily from ATSB bait stations situated indoors, leading to

  14. Primary and secondary parasitoids (Hymenoptera) of aphids (Hemiptera: Aphididae) on blueberry and other Vaccinium in the Pacific Northwest.

    Science.gov (United States)

    Raworth, D A; Pike, K S; Tanigoshi, L K; Mathur, S; Graf, G

    2008-04-01

    Blueberry scorch virus, a commercially important Carlavirus in highbush blueberry, Vaccinium corymbosum L., is vectored by aphids (Hemiptera: Aphididae). We surveyed the aphids, primary parasitoids (Hymenoptera: Aphelinidae, Braconidae), and associated secondary parasitoids (Hymenoptera: Charipidae, Megaspilidae, Pteromalidae) on highbush blueberry and other Vaccinium in the Pacific Northwest from 1995 to 2006, with samples concentrated in 2005 and 2006, to lay the groundwork for augmentative biological control. Ericaphis fimbriata (Richards) was the principal aphid. The dominant parasitoid species were Praon unicum Smith, Aphidius n. sp., A. sp., and Aphidius ervi Haliday. Their frequency in relation to the other primary parasitoids varied significantly with geographical area; P. unicum dominated the frequency distribution in southwestern British Columbia, A. n. sp., west of the Cascades, and A. sp. and A. ervi east of the Cascades. Among the secondary parasitoids, pteromalids dominated, and their frequency in relation to the other secondary parasitoids was lowest in southwestern British Columbia. The parasitization rate for P. unicum and A. n. sp. in southwestern British Columbia increased from May or June to a maximum of 0.080 +/- 0.024 and 0.090 +/- 0.084 (SD), respectively, in late July or early August. P. unicum emerged in the spring 4 wk before A. n. sp. The parasitization rate for P. unicum was lower in conventional than organic fields. Whereas aphid density increased monotonically, P. unicum had two spring peaks. A simulation model showed that these peaks could reflect discrete generations. Releases of insectary-reared P. unicum at 150 or 450 DD above 5.6 degrees C, summing from 1 January, may effectively augment the natural spring populations by creating overlapping generations.

  15. 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.

  16. The Identification and Prioritization of Effective Factors in Attracting Health Tourists to Kermanshah Province-West of Iran

    Directory of Open Access Journals (Sweden)

    Saeed Khani

    2015-08-01

    Full Text Available ​Background and objectives : Health tourism has drastically grown during the last decade as a form of specialized tourism. The development of this industry in Iran and Kermanshah requires attention to important factors such as marketing techniques, the performance of organizations and the surrounding environment situation. This study was designed and conducted to identify effective factors in attracting health tourists to Kermanshah Province. Material and Methods : In this descriptive-analytical research, the opinions of 70 major experts involved in health tourism of Kermanshah province were investigated using a researcher-made questionnaire in 2011. Descriptive statistical methods, diagrams, tables and SPSS Version 18 were used to display and analyze the data. Results : Cumulative frequency of responses with “much” and “very much” to the questions related to hypothesis one (the performance of the organizations related to health tourist attraction to the province, hypothesis two (marketing mix with health tourists to the province and hypothesis three (the situation of surrounding environment of the province were 95.%, 98.%, and 94.3 %, respectively. Thus, marketing factors, the performance of related organizations and the surrounding environment situation of the province are respectively the priorities in the prioritization among these three hypotheses. These findings are nearly in a similar line with several recent findings in Iran and the world. Conclusion : The prioritization of the mentioned factors in the hypotheses showed that effort for the development of the factors related to marketing mix should be placed in the highest priority in comparison with the other factors in Kermanshah province.

  17. Like-charge attraction of molecular cations in water: subtle balance between interionic interactions and ionic solvation effect.

    Science.gov (United States)

    Inagaki, Taichi; Aono, Shinji; Nakano, Hiroshi; Yamamoto, Takeshi

    2014-05-22

    Despite strong electrostatic repulsion, like-charged ions in aqueous solution can effectively attract each other via ion-water interactions. In this paper we investigate such an effective interaction of like-charged ions in water by using the 3D-RISM-SCF method (i.e., electronic structure theory combined with three-dimensional integral equation theory for molecular solvents). Free energy profiles are calculated at the CCSD(T) level for a series of molecular ions including guanidinium (Gdm(+)), alkyl-substituted ammonium, and aromatic amine cations. Polarizable continuum model (PCM) and mean-field QM/MM free energy calculations are also performed for comparison. The results show that the stability of like-charged ion pairs in aqueous solution is determined by a very subtle balance between interionic interactions (including dispersion and π-stacking interactions) and ionic solvation/hydrophobic effects and that the Gdm(+) ion has a rather favorable character for like-charge association among all the cations studied. Furthermore, we investigate the like-charge pairing in Arg-Ala-Arg and Lys-Ala-Lys tripeptides in water and show that the Arg-Arg pair has a contact free-energy minimum of about -6 kcal/mol. This result indicates that arginine pairing observed on protein surfaces and interfaces is stabilized considerably by solvation effects.

  18. Effects of Counselor and Subject Race and Counselor Physical Attractiveness on Impressions and Expectations of a Female Counselor.

    Science.gov (United States)

    Green, Cheryl F.; And Others

    1986-01-01

    Subjects' ratings of counselor charactristics were more positive for attractive than for unattractive counselors, regardless of subject or counselor race. Black counselors were expected to be more helpful than were White counselors. Black subjects saw attractive counselors as being more helpful than unattractive counselors. (Author/BL)

  19. 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…

  20. Effects of Communication Apprehension on Perceptions of Leadership and Intragroup Attraction in Small Task-Oriented Groups.

    Science.gov (United States)

    Hawkins, Katherine; Stewart, Robert A.

    1991-01-01

    Examines the impact of communication apprehension (CA) on perceptions of leadership and intragroup attraction in small task-oriented groups, using 68 undergraduates working on a class project. Finds high CA students were rated by themselves (and by others) to be lower in emerged leadership and social and task attraction than those with lower CA.…

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

    Directory of Open Access Journals (Sweden)

    Anna-Lena Cory

    2016-04-01

    Full Text Available 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.

  2. Effect of Bt genetic engineering on indirect defense in cotton via a tritrophic interaction.

    Science.gov (United States)

    Moraes, Maria Carolina Blassioli; Laumann, Raul Alberto; Aquino, Michely Ferreira Santos; Paula, Débora Pires; Borges, Miguel

    2011-02-01

    We present a tritrophic analysis of the potential non-intended pleiotropic effects of cry1Ac gene derived from Bacillus thurigiensis (Bt) insertion in cotton (DeltaPine 404 Bt Bollgard® variety) on the emission of herbivore induced volatile compounds and on the attraction of the egg parasitoid Trichogramma pretisoum (Hymenoptera: Trichogrammatidae). Both the herbivore damaged Bt variety and its non-Bt isoline (DeltaPine DP4049 variety) produced volatiles in higher quantity when compared to undamaged plants and significantly attracted the egg parasitoids (T. pretiosum) when compared to undamaged plants. However, Trichogramma pretiosum did not differentiate between the transgenic and nontransgenic varieties, suggesting that the ratios between the compounds released by herbivory damaged -Bt cotton and herbivory damaged-non Bt cotton did not change significantly. Finally, no detrimental effect of the Bt genetic engineering was detected related to the volatile compounds released by Bollgard cotton on the behavior of the natural enemy studied.

  3. Factors shaping life history traits of two proovigenic parasitoids.

    Science.gov (United States)

    Segoli, Michal; Sun, Shucun; Nava, Dori E; Rosenheim, Jay A

    2017-11-23

    What shapes the relative investment in reproduction vs. survival of organisms is one of the key questions in life history. Proovigenic insects mature all their eggs prior to emergence and are short lived, providing a unique opportunity to quantify their lifetime investments in the different functions. We investigated the initial eggloads and longevity of two proovigenic parasitoid wasps (Anagrus erythroneurae and Anagrus daanei, (Hymenoptera: Mymaridae) that develop within leafhopper eggs in both agricultural vineyards and natural riparian habitats in Northern California. We collected Vitis spp. leaves containing developing parasitoids from three natural sites (Knight Landing, American River and Putah Creek) and three agricultural vineyards (Solano Farm, Davis Campus and Village Homes). We recorded eggloads at parasitoid emergence and female parasitoid longevity with or without honey-feeding. Theory predicts that parasitoids from vineyards (where hosts are abundant) would have higher initial eggloads and lower longevity compared with parasitoids from riparian habitats (where hosts are scarce). Although host density and parasitoid eggloads were indeed higher in vineyards than in riparian habitats, parasitoid longevity did not follow the predicted pattern. Longevity without feeding differed among field sites, but it was not affected by habitat type (natural vs. agricultural), whereas longevity with feeding was not significantly affected by any of the examined factors. Moreover, longevity was positively, rather than negatively, correlated with eggloads at the individual level, even after correcting for parasitoid body size. The combined results suggest a more complex allocation mechanism than initially predicted, and the possibility of variation in host quality that is independent of size. This article is protected by copyright. All rights reserved. This article is protected by copyright. All rights reserved.

  4. Expressing an (E)-β-farnesene synthase in the chloroplast of tobacco affects the preference of green peach aphid and its parasitoid.

    Science.gov (United States)

    Wang, Gen-Ping; Yu, Xiu-Dao; Fan, Jia; Wang, Cheng-She; Xia, Lan-Qin

    2015-09-01

    (E)-β-Farnesene (EβF) synthase catalyses the production of EβF, which for many aphids is the main or only component of the alarm pheromone causing the repellence of aphids and also functions as a kairomone for aphids' natural enemies. Many plants possess EβF synthase genes and can release EβF to repel aphids. In order to effectively recruit the plant-derived EβF synthase genes for aphid control, by using chloroplast transit peptide (CTP) of the small subunit of Rubisco (rbcS) from wheat (Triticum aestivum L.), we targeted AaβFS1, an EβF synthase gene from sweet wormwood (Artemisia annua L.), to the chloroplast of tobacco to generate CTP + AaβFS1 transgenic lines. The CTP + AaβFS1 transgenic tobacco plants could emit EβF at a level up to 19.25 ng/day per g fresh tissues, 4-12 fold higher than the AaβFS1 transgenic lines without chloroplast targeting. Furthermore, aphid/parasitoid behavioral bioassays demonstrated that the CTP + AaβFS1 transgenic tobacco showed enhanced repellence to green peach aphid (Myzus persicae) and attracted response of its parasitoid Diaeretiella rapae, thus affecting aphid infestation at two trophic levels. These data suggest that the chloroplast is an ideal subcellular compartment for metabolic engineering of plant-derived EβF synthase genes to generate a novel type of transgenic plant emitting an alarm pheromone for aphid control. © 2014 Institute of Botany, Chinese Academy of Sciences.

  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 ...

  6. Temperature- and age-dependent survival, development, and oviposition rates of the pupal parasitoid Spalangia cameroni (Hymenoptera: Pteromalidae)

    DEFF Research Database (Denmark)

    Skovgård, Henrik; Nachman, Gösta

    2016-01-01

    The combined effect of temperature and age on development, survival, attack rate, and oviposition of the parasitoid Spalangia cameroni (Perkins) (Hymenoptera: Pteromalidae) exploiting house fly pupae was investigated by conducting life-table experiments at 15, 20, 25, 30 and 35°C. Temperature had...

  7. A comparison of nectar- and honeydew sugars with respect to their utilization by the hymenopteran parasitoid Cotesia glomerata

    NARCIS (Netherlands)

    Wäckers, F.L.

    2001-01-01

    Fourteen naturally occurring sugars were individually tested with respect to their effect on Cotesia glomerata longevity. Parasitoids kept with solutions of either sucrose, glucose and fructose lived for > 30 days. This constitutes a factor 15 increase in life span in comparison to control

  8. A comparison of nectar- and honeydew sugars with respect to their utilization by the hymenopteran parasitoid Cotesia glomerata

    NARCIS (Netherlands)

    Wäckers, F.L.

    2001-01-01

    Fourteen naturally occurring sugars were individually tested with respect to their effect on Cotesia glomerata longevity. Parasitoids kept with solutions of either sucrose, glucose and fructose lived for >30 days. This constitutes a factor 15 increase in life span in comparison to control

  9. 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, 4...

  10. 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.

  11. The effects of physical attractiveness on gaining access to alcohol: when social policy meets social decision making.

    Science.gov (United States)

    McCall, M

    1997-05-01

    Despite numerous legal interventions, minors continue to purchase and consume alcohol. Prior research had suggested that the decision to request identification to prove legal age was susceptible to various judgement and decision heuristics. This research examined whether the physical attractiveness of the potential consumer and the presence or absence of others were significant predictors of alcohol accessibility. Bartenders (n = 130) rated a target individual who was either high or low in attractiveness. Results indicated that attractiveness was a significant predictor of "proofing likelihood". High levels of attractiveness were associated with a decrease in the likelihood of being asked to provide proof of legal age for the purchase of alcohol. Individuals presented alone were seen as significantly older than when grouped with others. Implications of these findings for the restriction of alcohol availability among minors are considered.

  12. Effects of simulated approval-seeking and avoiding on self-disclosure, self-presentation, and interpersonal attraction.

    Science.gov (United States)

    Pellegrini, R J; Hicks, R A; Meyers-Winton, S

    1978-03-01

    Forty-eight undergraduate women assigned an approval-seeking or approval-avoiding role disclosed significantly more to a male listener (C) than did control Ss given no particular set, with no difference found between seeking and avoiding conditions in intimacy of disclosure. But content analyses indicated that approval-seeking Ss presented themselves significantly more positively, and approval-avoiding Ss significantly more negatively than did controls. These data supported the hypothesis that disclosure may serve as an instrumental affiliative act associated with both interpersonal approach and avoidance motives. The hypothesis that simulated attraction facilitates actual attraction was supported more clearly in analyses of Ss' liking ratings of C than in Ss' ratings of C's attractiveness or desirability as a dating partner. The latter findings are discussed in terms of intimacy implications of the attraction measures used.

  13. 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

  14. Specificity of Multi-Modal Aphid Defenses against Two Rival Parasitoids

    Science.gov (United States)

    Martinez, Adam J.; Kim, Kyungsun L.; Harmon, Jason P.; Oliver, Kerry M.

    2016-01-01

    Insects are often attacked by multiple natural enemies, imposing dynamic selective pressures for the development and maintenance of enemy-specific resistance. Pea aphids (Acyrthosiphon pisum) have emerged as models for the study of variation in resistance against natural enemies, including parasitoid wasps. Internal defenses against their most common parasitoid wasp, Aphidius ervi, are sourced through two known mechanisms– 1) endogenously encoded resistance or 2) infection with the heritable bacterial symbiont, Hamiltonella defensa. Levels of resistance can range from nearly 0–100% against A. ervi but varies based on aphid genotype and the strain of toxin-encoding bacteriophage (called APSE) carried by Hamiltonella. Previously, other parasitoid wasps were found to commonly attack this host, but North American introductions of A. ervi have apparently displaced all other parasitoids except Praon pequodorum, a related aphidiine braconid wasp, which is still found attacking this host in natural populations. To explain P. pequodorum’s persistence, multiple studies have compared direct competition between both wasps, but have not examined specificity of host defenses as an indirectly mediating factor. Using an array of experimental aphid lines, we first examined whether aphid defenses varied in effectiveness toward either wasp species. Expectedly, both types of aphid defenses were effective against A. ervi, but unexpectedly, were completely ineffective against P. pequodorum. Further examination showed that P. pequodorum wasps suffered no consistent fitness costs from developing in even highly ‘resistant’ aphids. Comparison of both wasps’ egg-larval development revealed that P. pequodorum’s eggs have thicker chorions and hatch two days later than A. ervi’s, likely explaining their differing abilities to overcome aphid defenses. Overall, our results indicate that aphids resistant to A. ervi may serve as reservoirs for P. pequodorum, hence contributing to

  15. Specificity of Multi-Modal Aphid Defenses against Two Rival Parasitoids.

    Directory of Open Access Journals (Sweden)

    Adam J Martinez

    Full Text Available Insects are often attacked by multiple natural enemies, imposing dynamic selective pressures for the development and maintenance of enemy-specific resistance. Pea aphids (Acyrthosiphon pisum have emerged as models for the study of variation in resistance against natural enemies, including parasitoid wasps. Internal defenses against their most common parasitoid wasp, Aphidius ervi, are sourced through two known mechanisms- 1 endogenously encoded resistance or 2 infection with the heritable bacterial symbiont, Hamiltonella defensa. Levels of resistance can range from nearly 0-100% against A. ervi but varies based on aphid genotype and the strain of toxin-encoding bacteriophage (called APSE carried by Hamiltonella. Previously, other parasitoid wasps were found to commonly attack this host, but North American introductions of A. ervi have apparently displaced all other parasitoids except Praon pequodorum, a related aphidiine braconid wasp, which is still found attacking this host in natural populations. To explain P. pequodorum's persistence, multiple studies have compared direct competition between both wasps, but have not examined specificity of host defenses as an indirectly mediating factor. Using an array of experimental aphid lines, we first examined whether aphid defenses varied in effectiveness toward either wasp species. Expectedly, both types of aphid defenses were effective against A. ervi, but unexpectedly, were completely ineffective against P. pequodorum. Further examination showed that P. pequodorum wasps suffered no consistent fitness costs from developing in even highly 'resistant' aphids. Comparison of both wasps' egg-larval development revealed that P. pequodorum's eggs have thicker chorions and hatch two days later than A. ervi's, likely explaining their differing abilities to overcome aphid defenses. Overall, our results indicate that aphids resistant to A. ervi may serve as reservoirs for P. pequodorum, hence contributing to

  16. 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.

  17. Interspecific interactions between two Tuta absoluta (Lepidoptera: Gelechiidae) larval parasitoids with contrasting life histories.

    Science.gov (United States)

    Savino, V; Luna, M G; Salas Gervassio, N G; Coviella, C E

    2017-02-01

    Interspecific interactions between two larval parasitoids of Tuta absoluta (Meyrick) with partially overlapping host niches were studied: the idiobiont ectoparasitoid Dineulophus phthorimaeae De Santis, and the koinobiont endoparasitoid Pseudapanteles dignus (Muesebeck). T. absoluta is an important pest of tomato crops worldwide, and its management could be improved by understanding the competitive interactions and potential coexistence between these two parasitoids. Firstly, a 15-min fixed time laboratory test evaluated the host-searching ability of adult D. phthorimaeae and P. dignus wasps on T. absoluta larvae. Secondly, D. phthorimaeae host discrimination against endoparasitized and non-endoparasitized hosts by P. dignus, at different adult female ages, was experimentally examined. D. phthorimaeae wasps spent significantly more time in general searching in the presence of its competitor than in its absence, but, parasitism was only effective by P. dignus. Older D. phthorimaeae wasps discriminated significantly less than young wasps between T. absoluta larvae parasitized and unparasitized by P. dignus, and an interaction took place by non-concurrent host-feeding. Intra-guild predation of P. dignus larvae by D. phthorimaeae female feeding behaviour might have a minor effect in this system. Results are discussed in the context of literature supporting diverse evidence of coexistence in other parasitoid-host systems, with implications for T. absoluta biological control.

  18. 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.

  19. 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. (c) 2007 APA

  20. Honey and honey-based sugars partially affect reproductive trade-offs in parasitoids exhibiting different life-history and reproductive strategies.

    Science.gov (United States)

    Harvey, Jeffrey A; Essens, Tijl A; Las, Rutger A; van Veen, Cindy; Visser, Bertanne; Ellers, Jacintha; Heinen, Robin; Gols, Rieta

    2017-04-01

    Adult dietary regimes in insects may affect egg production, fecundity and ultimately fitness. This is especially relevant in parasitoid wasps where many species serve as important biological control agents of agricultural pests. Here, we tested the effect of honey and sugar diets on daily fecundity schedules, lifetime reproductive success and longevity in four species of parasitoid wasps when reared on their respective hosts. The parasitoid species were selected based on dichotomies in host usage strategies and reproductive traits. Gelis agilis and G. areator are idiobiont ecto-parasitoids that develop in non-growing hosts, feed on protein-rich host fluids to maximize reproduction as adults and produce small numbers of large eggs. Meteorus pulchricornis and Microplitis mediator are koinobiont endoparasitoids that develop inside the bodies of growing hosts, do not host-feed, and produce greater numbers of small eggs. Parasitoids were reared on diets of either pure honey (containing trace amounts of proteins), heated honey (with denatured proteins) and a honey-mimic containing sugars only. We hypothesized that the benefits of proteins in honey would enhance reproduction in the ectoparasitoids due to their high metabolic investment per egg, but not in the koinobionts. Pure honey diet resulted in higher lifetime fecundity in G. agilis compared with the honey-mimic, whereas in both koinobionts, reproductive success did not vary significantly with diet. Longevity was less affected by diet in all of the parasitoids, although there were variable trade-offs between host access and longevity in the four species. We argue that there are both trait-based and association-specific effects of supplementary nutrients in honey on reproductive investment and success in parasitoid wasps. Copyright © 2016 Elsevier Ltd. All rights reserved.

  1. Parasitoid wasps: from natural history to genomic studies.

    Science.gov (United States)

    Wurm, Yannick; Keller, Laurent

    2010-03-09

    The sequencing of three Nasonia genomes provides new insights on the molecular signature associated with parasitoid lifestyle, allows comparison with the social honey bee, and enables the identification of genes underlying between-species and sex-specific differences.

  2. Parasitoid Wasps: From Natural History to Genomic Studies

    OpenAIRE

    Wurm, Yannick; Keller, Laurent

    2010-01-01

    The sequencing of three Nasonia genomes provides new insights on the molecular signature associated with parasitoid lifestyle, allows comparison with the social honey bee, and enables the identification of genes underlying between-species and sex-specific differences.

  3. Olfactory host location in beetle bruchid parasitoid Dinarmus basalis ...

    African Journals Online (AJOL)

    Hymenoptera : Pteromalidae). O Rabi, AD Bouli, JP Monge. Abstract. The role of chemicals cues in host location by the parasitoid Dinarmus basalis (Rond.) was investigated in bioassays by measuring response to stimuli associated with one of its hosts, ...

  4. Olfactory host location in beetle bruchid parasitoid Dinarmus basalis ...

    African Journals Online (AJOL)

    Rond.) was investigated in bioassays by measuring response to stimuli associated with one of its hosts, the larvae of beetle bruchid, Bruchidius atrolineatus (Pic.) infesting Vigna unguiculata (L. Walp.) seeds. Orientation of parasitoid females was ...

  5. Biología del parasitoide Psyllaephagus bliteus (Hymenoptera: Encyrtidae

    Directory of Open Access Journals (Sweden)

    A. Plascencia-González

    2005-01-01

    Full Text Available En Chapingo, M xico, fueron estudiados varios aspectos de la biolog a del parasitoide Psyllaephagus bliteus. Se describe el huevo, larva, pupa y adultos. Los huevos son depositados dentro del abdomen del segundo o tercer nstar ninfal de su hospedante, Glycaspis brimblecombei. La larva y la pupa del parasitoide se desarrollan dentro del cuerpo de la ninfa. El dimorfismo sexual entre la hembra y el macho es evidente, las antenas son diferentes en ambos sexos. El ciclo biol gico del parasitoide es de 16.3 a 41.6 d as y est influenciado por las condiciones ambientales. En cajas de cr a con plantas de Eucalyptus camaldulensis infestadas con G. brimblecombei se obtuvo un n mero promedio de progenie por hembra parasitoide de 17 individuos (m nimo 4 y m ximo 46 la proporci n de sexos fue ligeramente mayor en hembras (1.1 :1 .

  6. 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

  7. 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)

  8. 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.

  9. When parasitoid males make decisions: information used when foraging for females.

    Directory of Open Access Journals (Sweden)

    Claire M-S Dufour

    Full Text Available Optimal foraging models predict how an organism allocates its time and energy while foraging for aggregated resources. These models have been successfully applied to organisms such as predators looking for prey, female parasitoids looking for hosts, or herbivorous searching for food. In this study, information use and patch time allocation were investigated using male parasitoids looking for mates. The influence of the former presence of females in absence of mates and the occurrence of mating and other reproductive behaviours on the patch leaving tendency was investigated for the larval parasitoid Asobara tabida. Although males do not modify their patch residence time based on the number of females that visited the patch, they do show an increase in the patch residence time after mating a virgin female and performing courtship behaviour such as opening their wings. These results are in concordance with an incremental mechanism, as it has been described for females of the same species while foraging for hosts. The similarities between males and females of the same species, and the conditions under which such a patch-leaving decision rule is fitted are discussed. This is the first study describing an incremental effect of mating on patch residence time in males, thus suggesting that similar information use are probably driving different organisms foraging for resource, regardless of its nature.

  10. When parasitoid males make decisions: information used when foraging for females.

    Science.gov (United States)

    Dufour, Claire M-S; Louâpre, Philippe; van Baaren, Joan; Martel, Véronique

    2012-01-01

    Optimal foraging models predict how an organism allocates its time and energy while foraging for aggregated resources. These models have been successfully applied to organisms such as predators looking for prey, female parasitoids looking for hosts, or herbivorous searching for food. In this study, information use and patch time allocation were investigated using male parasitoids looking for mates. The influence of the former presence of females in absence of mates and the occurrence of mating and other reproductive behaviours on the patch leaving tendency was investigated for the larval parasitoid Asobara tabida. Although males do not modify their patch residence time based on the number of females that visited the patch, they do show an increase in the patch residence time after mating a virgin female and performing courtship behaviour such as opening their wings. These results are in concordance with an incremental mechanism, as it has been described for females of the same species while foraging for hosts. The similarities between males and females of the same species, and the conditions under which such a patch-leaving decision rule is fitted are discussed. This is the first study describing an incremental effect of mating on patch residence time in males, thus suggesting that similar information use are probably driving different organisms foraging for resource, regardless of its nature.

  11. Manure Preferences and Postemergence Learning of Two Filth Fly Parasitoids, Spalangia cameroni and Muscidifurax raptor (Hymenoptera: Pteromalidae.

    Directory of Open Access Journals (Sweden)

    Caitlin E Taylor

    Full Text Available The efficiency of host-seeking behavior is crucial to the reproductive performance of female parasitoids. Initially, parasitoids may use chemical information garnered from the microhabitat in which they emerge to locate hosts. Spalangia cameroni and Muscidifurax raptor are commercially available parasitoids of filth flies. Postemergence exposure to a specific manure may provide a way to increase parasitism in specific microhabitats found at livestock facilities upon release. In this study, female parasitoids of both species were exposed to equine manure, bovine manure, or clean pupae. Females from each emergence exposure were tested in a two-choice arena (house fly hosts in bovine manure versus clean pupae, equine manure versus clean pupae, and equine manure versus bovine manure for progeny production. There was a detectable but small effect of postemergence exposure on S. cameroni, but it was not sufficient to reverse innate preferences. Females consistently produced more progeny in hosts found in any manure over clean pupae, and in equine manure over bovine manure. The effect of postemergence exposure on M. raptor was also detectable but small. Females produced equal numbers of progeny in bovine manure versus clean pupae, as opposed to preferring to oviposit in clean pupae as with all other treatments. Preferences by M. raptor were overall less marked than for S. cameroni; indeed most of the variability observed for this species did not result from the treatment design. Residual host mortality was also detectably altered by exposure in both species, but the effect was small. Thus, postemergence exposure did not consistently and effectively manipulate these parasitoids to producing progeny in different exposure manures, suggesting that microhabitat preferences are largely determined by other factors.

  12. Ecology and life history evolution of frugivorous Drosophila parasitoids.

    Science.gov (United States)

    Fleury, Frédéric; Gibert, Patricia; Ris, Nicolas; Allemand, Roland

    2009-01-01

    Parasitoids and their hosts are linked by intimate and harmful interactions that make them well suited to analyze fundamental ecological and evolutionary processes with regard to life histories evolution of parasitic association. Drosophila aspects of what parasitoid Hymenoptera have become model organisms to study aspects that cannot be investigated with other associations. These include the genetic bases of fitness traits variations, physiology and genetics of resistance/virulence, and coevolutionary dynamics leading to local adaptation. Recent research on evolutionary ecology of Drosophila parasitoids were performed mainly on species that thrive in fermenting fruits (genera Leptopilina and Asobara). Here, we review information and add original data regarding community ecology of these parasitoids, including species distribution, pattern of abundance and diversity, host range and the nature and intensity of species interactions. Biology and the evolution of life histories in response to habitat heterogeneity and possible local adaptations leading to specialization of these wasps are reported with special emphasis on species living in southern Europe. We expose the diversity and intensity of selective constraints acting on parasitoid life history traits, which vary geographically and highlight the importance of considering both biotic and abiotic factors with their interactions to understand ecological and evolutionary dynamics of host-parasitoid associations.

  13. 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.

  14. Effect of Olive Branch Aging and Extracts on the Attraction of Olive Neiroun Beetles Phloeotribus Scarabeioides (Bern

    Directory of Open Access Journals (Sweden)

    T. M. Mustafa

    1997-01-01

    Full Text Available The response of the olive neiroun beetle Phloeorribus scarabeiuides (Bern to the aging of detached olive branches at different periods of time was investigated in the laboratory using an olfactometer and in the field. Results showed that ten-day aged branches were the most attractive to the olive neiroun, indicating that semi-dried branches were more preferred than dry or fresh ones. Furthermore,  the efficiency of certain chemical solvents including n-hexane. Chloroform, acetone, methanol and distilled water in extracting the attractive substances in olive branches was studied using an olfactometer. Acetone extract was found to be the most efficient in attracting adults P. Scarabeioides. The study indicates that the olive neiroun may locate the stressed host trees or detached branches by olfactory perception of volatile compounds resulting from the stressed host tissues.

  15. Indirect multi-trophic interactions mediated by induced plant resistance: impact of caterpillar feeding on aphid parasitoids.

    Science.gov (United States)

    Hagenbucher, Steffen; Wäckers, Felix L; Romeis, Jörg

    2014-02-01

    Cotton produces insecticidal terpenoids that are induced by tissue-feeding herbivores. Damage by Heliothis virescens caterpillars increases the terpenoid content, which reduces the abundance of aphids. This effect is not evident in Bt-transgenic cotton, which is resistant to H. virescens. We determined whether induction of terpenoids by caterpillars influences the host quality of Aphis gossypii for the parasitoid Lysiphlebus testaceipes and whether this interaction is influenced by Bt cotton. The exposure of parasitoids to terpenoids was determined by quantifying terpenoids in the aphids. We detected several terpenoids in aphids and found a positive relationship between their concentrations in plants and aphids. When L. testaceipes was allowed to parasitize aphids on Bt and non-Bt cotton that was infested or uninfested with H. virescens, fewer parasitoid mummies were found on infested non-Bt than on Bt cotton. Important parasitoid life-table parameters, however, were not influenced by induced resistance following H. virescens infestation, or the Bt trait. Our study provides an example of a tritrophic indirect interaction web, where organisms are indirectly linked through changes in plant metabolites.

  16. 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 <25 % mortality to 17 and 24 days after spraying (DAS), respectively. Chlorpyrifos and β-cyfluthrin were considered slightly persistent (mortality <25 %, 7 DAS). Although abamectin was considered harmless to A. citricola adults, had a short life (mortality <25 %, 3 DAS), and did not significantly affect the parasitism rate, the number and viability of pupae, or the longevity of A. citricola, this insecticide significantly reduced the proportion of females in the progeny compared to the 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.

  17. The exploration of fruit flies Bactrocera (Diptera:Tephritidae and its parasitoid in Madura Island regions

    Directory of Open Access Journals (Sweden)

    Tjipto Haryono

    2016-07-01

    Full Text Available Madura is enriched by great diversity despite of its infertile natural condition. This condition influences fruit flies existence and diversity. Purpose of this study was to investigate the diversity and distribution of fruit flies with their host in Madura region. Sampling methods in this study were fruit host collection (rearing and trapping using Steiner-type trap that were set in 48 locations in several villages in Bangkalan, Sampang, Pamekasan, and Sumenep regencies. Steiner traps were combined with 2 different attractants, such as methyl eugenol (ME and Cue Lure (CL. There were 5 species of fruit flies obtained from trapping and rearing, namely Bactrocera carambolae, B. papayae, B. umbrosa, B. albistrigata, and B. cucurbitae. Results indicate that the distribution, diversity, and abundance of fruit flies were influenced by the diversity of fruit host, air temperature, and relative air humidity. It is also identified two species of parasitoid imago from rotten fruits collection, namely Biosteres vandenboschi and Fopius arisanus. Keywords: distribution, Bactrocera, parasitoid

  18. Effects of self-attraction and loading at a regional scale: a test case for the Northwest European Shelf

    Science.gov (United States)

    Irazoqui Apecechea, Maialen; Verlaan, Martin; Zijl, Firmijn; Le Coz, Camille; Kernkamp, Herman

    2017-06-01

    The impact of the self-attraction and loading effect (SAL) in a regional 2D barotropic tidal model has been assessed, a term with acknowledged and well-understood importance for global models but omitted for boundary-forced, regional models, for which the implementation of SAL is non-trivial due to its non-local nature. In order to understand the impact of the lack of SAL effects in a regional scale, we have forced a regional model of the Northwest European Continental Shelf and the North Sea (continental shelf model (CSM)) with the SAL potential field derived from a global model (GTSM), in the form of a pressure field. Impacts have been studied in an uncalibrated setup and with only tidal forcing activated, in order to isolate effects. Additionally, the usually adopted simple SAL parameterization, in which the SAL contribution to the total tide is parameterized as a percentage of the barotropic pressure gradient (typically chosen 10%), is also implemented and compared to the results obtained with a full SAL computation. A significant impact on M2 representation is observed in the English Channel, Irish Sea and the west (UK East coast) and south (Belgian and Dutch Coast) of the North Sea, with an impact of up to 20 cm in vector difference terms. The impact of SAL translates into a consistent M2 amplitude and propagation speeds reduction throughout the domain. Results using the beta approximation, with an optimal domain-wide constant value of 1.5%, show a somewhat comparable impact in phase but opposite direction of the impact in amplitude, increasing amplitudes everywhere. In relative terms, both implementations lead to a reduction of the tidal representation error in comparison with the reference run without SAL, with the full SAL approach showing further impacted, improved results. Although the overprediction of tidal amplitudes and propagation speeds in the reference run might have additional sources like the lack of additional dissipative processes and non

  19. Biology of the parasitoid Melittobia (Hymenoptera: Eulophidae).

    Science.gov (United States)

    Matthews, Robert W; González, Jorge M; Matthews, Janice R; Deyrup, Leif D

    2009-01-01

    As parasitoids upon solitary bees and wasps and their nest cohabitants, Melittobia have an intricate life history that involves both female cooperation and variably expressed male siblicidal conflict. Inter- and intrasexual dimorphism includes blind, flightless males and (probably nutritionally determined) short- and long-winged females. Thought to be highly inbred, Melittobia do not conform to local mate competition (LMC) theory but exhibit simple forms of many social insect traits, including overlapping adult generations, different female phenotypes, close kinship ties, parental care, and altruistic cooperative escape behaviors. Most host records and research findings are based on only 3 species--M. acasta, M. australica, and M. digitata--but any of the 12 species could have pest potential due to their polyphagy, explosive population growth, cryptic habits, and behavioral plasticity. Readily cultured in the laboratory, Melittobia offer considerable potential as a model for genetic, developmental, and behavioral studies.

  20. Venom of parasitoid, Pteromalus puparum, suppresses host, Pieris rapae, immune promotion by decreasing host C-type lectin gene expression.

    Directory of Open Access Journals (Sweden)

    Qi Fang

    Full Text Available Insect hosts have evolved immunity against invasion by parasitoids, and in co-evolutionary response parasitoids have also developed strategies to overcome host immune systems. The mechanisms through which parasitoid venoms disrupt the promotion of host immunity are still unclear. We report here a new mechanism evolved by parasitoid Pteromalus puparum, whose venom inhibited the promotion of immunity in its host Pieris rapae (cabbage white butterfly.A full-length cDNA encoding a C-type lectin (Pr-CTL was isolated from P. rapae. Quantitative PCR and immunoblotting showed that injection of bacterial and inert beads induced expression of Pr-CTL, with peaks of mRNA and Pr-CTL protein levels at 4 and 8 h post beads challenge, respectively. In contrast, parasitoid venom suppressed Pr-CTL expression when co-injected with beads, in a time and dose-dependent manner. Immunolocalization and immunoblotting results showed that Pr-CTL was first detectable in vesicles present in cytoplasm of granulocytes in host hemolymph, and was then secreted from cells into circulatory fluid. Finally, the secreted Pr-CTL bound to cellular membranes of both granulocytes and plasmatocytes. Injection of double-stranded RNA specific for target gene decreased expression of Pr-CTL, and a few other host immune-related genes. Suppression of Pr-CTL expression also down-regulated antimicrobial and phenoloxidase activities, and reducing phagocytotic and encapsulation rates in host. The inhibitory effect of parasitoid venom on host encapsulation is consistent with its effect in suppressing Pr-CTL expression. Binding assay results showed that recombinant Pr-CTL directly attached to the surface of P. puparum egges. We infer that Pr-CTL may serve as an immune signalling co-effector, first binding to parasitoid eggs, regulating expression of a set of immune-related genes and promoting host immunity.P. puparum venom inhibits promotion of host immune responses by silencing expression of host C

  1. Parasitoids (Hymenoptera: Braconidae, Aphidiinae of the mealy plum aphid Hyalopterus pruni (Geoffr. on common reed (Phragmites australis in different types of habitat in Poland

    Directory of Open Access Journals (Sweden)

    Barczak T.

    2013-01-01

    Full Text Available The aim of the present work was to determine the parasitoid guild of the mealy plum aphid Hyalopterus pruni on common reed (Phragmites australis in different types of habitats in central Poland. The investigations were carried out in selected areas of the Salted Kujawy Region (central-northern Poland. To compare the parasitoid guilds of H. pruni from common reed in different types of habitats, species composition, number, domination structure and the percentage of parasitization (effectiveness were evaluated. The primary parasitoid guild of H. pruni on common reed in central Poland comprises three aphidiine braconids, mainly Praon volucre and P. abjectum. The number of the primary parasitoid species and their effectiveness in the aphid colonies were very low. Hence, common reed did not seem to be a good reservoir of the H. pruni parasitoids, but it may play a role as a place of dispersion of these insects, beneficial to orchards. A very low number of the hyperparasitoids were observed in the aphid colonies.

  2. Efficiency of vibrational sounding in the parasitoid Pimpla turionellae is affected by female size

    NARCIS (Netherlands)

    Otten, H.; Wäckers, F.; Battini, M.; Dorn, S.

    2001-01-01

    The pupal parasitoid Pimpla (=Coccygomimus) turionellae L. (Hymenoptera: Ichneumonidae) attacks a broad range of lepidopteran pupae. The variation in host size translates into substantial differences in size among adult parasitoids. Pimpla turionellae shows a strong host size-dependent sex

  3. 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 emerging...

  4. 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

  5. Community composition and species richness of parasitoids infesting Yponomeuta species in the Netherlands

    NARCIS (Netherlands)

    Cleary, Daniel F.R.

    2004-01-01

    Parasitoid assemblages infesting Yponomeuta species in the Netherlands were investigated. Parasitoid species richness and community composition were related to host species, habitat, temporal and spatial variation. Both community structure and species richness did not differ among habitats. There

  6. Effect of chemical ratios of a microbial-based feeding attractant on trap catch of spotted wing drosophila (Diptera: Drosophilidae)

    Science.gov (United States)

    Drosophila suzukii Matsumura (SWD) can be trapped with a feeding attractant based on wine and vinegar volatiles and consisting of acetic acid, ethanol, acetoin and methionol. Using that 4-component blend, we found that the catch of SWD increased with increases in the release rate of acetoin (from 0...

  7. 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

  8. (Psychological) Distance Makes the Heart Grow Fonder: Effects of Psychological Distance and Relative Intelligence on Men's Attraction to Women.

    Science.gov (United States)

    Park, Lora E; Young, Ariana F; Eastwick, Paul W

    2015-11-01

    Interpersonal attraction may be shaped by (a) one's psychological distance from a target (the subjective experience that a target is close to or far from the self) and (b) the perceived standing of a target on a trait relative to the self (as better or worse than the self). We propose that when evaluating a psychologically distant target, individuals may rely on abstract schemas (e.g., the desirability of a partner's traits) and prefer targets who possess more (vs. less) desirable qualities than themselves. However, when evaluating psychologically near targets, concrete contextual details of the environment (e.g., how a target's behavior affects self-evaluations in the moment) may determine individuals' attraction toward targets. Six studies revealed that when evaluating psychologically distant targets, men showed greater attraction toward women who displayed more (vs. less) intelligence than themselves. In contrast, when targets were psychologically near, men showed less attraction toward women who outsmarted them. © 2015 by the Society for Personality and Social Psychology, Inc.

  9. 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…

  10. Prey and non-prey arthropods sharing a host plant : Effects on induced volatile emission and predator attraction

    NARCIS (Netherlands)

    de Boer, Jetske G.; Hordijk, Cornelis A.; Posthumus, Maarten A.; Dicke, Marcel

    It is well established that plants infested with a single herbivore species can attract specific natural enemies through the emission of herbivore-induced volatiles. However, it is less clear what happens when plants are simultaneously attacked by more than one species. We analyzed volatile

  11. Prey and Non-prey Arthropods Sharing a Host Plant: Effects on Induced Volatile Emission and Predator Attraction

    NARCIS (Netherlands)

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

    2008-01-01

    It is well established that plants infested with a single herbivore species can attract specific natural enemies through the emission of herbivore-induced volatiles. However, it is less clear what happens when plants are simultaneously attacked by more than one species. We analyzed volatile

  12. The Beauty of Counseling: Effects of Counselor Physical Attractiveness and Self-Disclosure on Perceptions of Counselor Behavior.

    Science.gov (United States)

    Cash, Thomas F.; Salzbach, Ronald F.

    1978-01-01

    Investigated influences of physical attractiveness and self-disclosures of nonprofessional counselors in initial counseling interviews. College females saw audiotaped interviews in which an unidentified male counselor revealed no self-information or expressed demographic or personal similarity self-disclosures. Nondisclosing, unattractive…

  13. Erratum: Erratum to: Effects of self-attraction and loading at a regional scale: a test case for the Northwest European Shelf

    Science.gov (United States)

    Irazoqui Apecechea, Maialen; Verlaan, Martin; Zijl, Firmijn; Le Coz, Camille; Kernkamp, Herman

    2017-12-01

    The article Effects of self-attraction and loading at a regional scale: a test case for the Northwest European Shelf, written by Maialen Irazoqui Apecechea, Martin Verlaan, Firmijn Zijl, Camille Le Coz and Herman Kernkamp, was originally published Online First without open access.

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

    Science.gov (United States)

    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 r...

  15. New trends in Ukraine investment attractiveness

    OpenAIRE

    Салабай, Владиcлав Олександрович; Манаєнко, Ірина Миколаївна

    2017-01-01

    The article analyzes the current state of the investment attractiveness of Ukraine. The structure of foreign investments in the national economy. Identified the main problem of attracting foreign investments into national economic, a state of the investment climate in Ukraine by international rating. Analyzed the investment index of the attractiveness by methodic of EBA. The effect of significant global investors on the investment attractiveness of the country, including George Soros. Proved ...

  16. Acute Toxicity of Fresh and Aged Residues of Pesticides to the Parasitoid Tamarixia radiata and to the HLB-Bacteria Vector Diaphorina citri.

    Science.gov (United States)

    Beloti, V H; Alves, G R; Moral, R A; Demétrio, C G B; Yamamoto, P T

    2017-12-08

    One method for controlling the Asian citrus psyllid (ACP) Diaphorina citri Kuwayama, the vector of the putative causal agent of Huanglongbing, uses the parasitoid Tamarixia radiata (Waterston). However, the general intensive use of insecticides has reduced the numbers of this parasitoid. This study evaluated the effect of the residual action of 24 insecticides on T. radiata and also determined the differential toxicity of insecticides to D. citri and T. radiata, using three bioassays. In the first, when adults of the parasitoid were exposed to residues of the 24 insecticides, ten were considered short-life (class 1), six slightly persistent (class 2), five moderately persistent (class 3), and three insecticides were considered persistent (class 4), under the IOBC/WPRS classification system. The second bioassay evaluated the sublethal concentrations of the persistent insecticides (formetanate, dimethoate, spinosad). Increasing the concentrations of the insecticides increased the number that were classified as persistent. In the third bioassay, evaluation of the differential toxicity of eight insecticides to the ACP and the parasitoid showed that chlorpyrifos and bifenthrin were more harmful to T. radiata. Therefore, these two insecticides are not recommended for application at the time of parasitoid release. Cypermethrin, imidacloprid, and dimethoate caused higher mortality of D. citri and are most often recommended in IPM programs. The choice of an insecticide for the control of citrus pests must be made with care, aiming to preserve the natural enemies in the ecosystem, and thereby contribute to the success of biological control.

  17. HPLC sugar analysis reveals the nutritional state and the feeding history of parasitoids

    NARCIS (Netherlands)

    Steppuhn, A.; Wäckers, F.L.

    2004-01-01

    1. Adult parasitoids depend on sugar-rich foods such as nectar and honeydew to meet their energy requirements. Many laboratory studies have established fitness benefits of sugar feeding for parasitoids. 2. Nevertheless, we know little about the nutritional ecology of parasitoids in the field,

  18. Distinguishing the effects of familiarity, relatedness, and color pattern rarity on attractiveness and measuring their effects on sexual selection in guppies (Poecilia reticulata).

    Science.gov (United States)

    Zajitschek, Susanne R K; Brooks, Robert C

    2008-12-01

    Mate choice is often based on multiple signal traits and can be influenced by context-dependent factors. Understanding the importance of these signals and factors can be difficult because they are often correlated and might interact. Here, we experimentally disentangle the effects of familiarity, kinship, pattern rarity, and ornament patterns on mate choice in guppies. We estimate whether these factors alter sexual selection on six phenotypic traits known to influence male attractiveness. Rarity of the male's phenotype is the only context-dependent factor that significantly influenced female mating decisions, with common patterns being least attractive. This preference for rare male patterns is a source of negative frequency-dependent selection that may contribute to maintaining the extreme polymorphism in male guppy coloration. Neither visual familiarity nor relatedness between mating partners had any significant effect on mate choice decisions. There was significant linear and nonlinear sexual selection on ornamental traits, but this was not influenced by the context-dependent measures. Our approach highlights the complexity of female mate choice and sexual selection, as well as the value of combining multifactorial experiments with multivariate selection analyses. Our study shows that both negative frequency-dependent selection and disruptive selection contribute to the maintenance of extreme polymorphism in guppies.

  19. Wildlife feeding in parks: methods for monitoring the effectiveness of educational interventions and wildlife food attraction behaviors

    Science.gov (United States)

    Marion, Jeffrey L.; Dvorak, Robert G.; Manning, Robert E.

    2008-01-01

    Opportunities to view and interact with wildlife are often an important part of high quality recreational experiences. Such interactions frequently include wildlife feeding, resulting in food-conditioned behaviors that may cause harm to both wildlife and visitors. This study developed and applied efficient protocols for simultaneously evaluating wildlife feeding-related behaviors of visitors and related foraging behaviors of chipmunks along a trail in Zion National Park. Unobtrusive observation protocols permitted an evaluation of educational messages delivered, and documentation of wildlife success in obtaining human food and the strength of their food attraction behavior. Significant improvements were documented for some targeted visitor behaviors and human food available to chipmunks, with minor differences between treatments. Replication of these protocols as part of a long-term monitoring program can help protected area managers evaluate and improve the efficacy of their interventions and monitor the strength of food attraction behavior in wildlife.

  20. Why do men prefer nice women? Gender typicality mediates the effect of responsiveness on perceived attractiveness in initial acquaintanceships.

    Science.gov (United States)

    Birnbaum, Gurit E; Ein-Dor, Tsachi; Reis, Harry T; Segal, Noam

    2014-10-01

    Responsiveness may signal to a potential partner that one is concerned with her or his welfare, and may therefore increase sexual interest in this person. Research shows, however, that this proposition holds true for men, but not for women. In three studies, one observational and two experimental, we explored a potential mechanism that explains why men and women diverge in their sexual reactions to a responsive opposite-sex stranger. Studies 1 and 2 showed that men, but not women, perceived a responsive stranger as more gender typical (masculine/feminine) and, in turn, as more attractive. Study 3 revealed that responsiveness increased men's perception of partner's femininity. This, in turn, was associated with higher sexual arousal, which was, in turn, linked to greater partner attractiveness and greater desire for a long-term relationship. These findings suggest that whether responsiveness affects perceptions of partner attractiveness varies in individuals, depending on the contextually based meaning of responsiveness. © 2014 by the Society for Personality and Social Psychology, Inc.

  1. 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.

  2. Effect of Copulins on Rating of Female Attractiveness, Mate-Guarding, and Self-Perceived Sexual Desirability

    Directory of Open Access Journals (Sweden)

    Megan N. Williams

    2016-04-01

    Full Text Available Olfaction and chemical signaling play an important role in the mating behaviors of many taxa, yet there is minimal empirical research on human putative pheromones. A mixture of five volatile fatty acids secreted vaginally, identified and named “copulins,” significantly increase in concentration during the follicular phase and decrease in concentration during the luteal phase in nonpill using women. Men exposed to copulins exhibit an increase in testosterone, are inhibited in discriminating the attractiveness of women’s faces, and behave less cooperatively. According to Anisogamy, Sexual Selection and Parental Investment Theory, mammalian males, having low cost and high benefit from any copulatory interaction, may adaptively utilize any useful cues to identifying ovulating females and adjust their behavior accordingly in order to maximize their potential reproductive success. In the current study, we attempted a replication of Jütte and Grammer’s finding indicating copulins inhibit the ability of men to discriminate attractiveness of women’s faces, and we examined the role of copulins in self-reported mate-guarding behaviors and self-perceived sexual desirability. We utilized a randomized placebo-controlled design and as predicted, results indicated men exposed to copulins were more likely to rate themselves as sexually desirable to women and, on average, the copulin group rated women’s faces as more attractive than controls. There were no significant findings with mate guarding.

  3. 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…

  4. High nymphal host density and mortality negatively impact parasitoid complex during an insect herbivore outbreak.

    Science.gov (United States)

    Hall, Aidan A G; Johnson, Scott N; Cook, James M; Riegler, Markus

    2017-08-26

    Insect herbivore outbreaks frequently occur and this may be due to factors that restrict top-down control by parasitoids, for example, host-parasitoid asynchrony, hyperparasitization, resource limitation and climate. Few studies have examined host-parasitoid density relationships during an insect herbivore outbreak in a natural ecosystem with diverse parasitoids. We studied parasitization patterns of Cardiaspina psyllids during an outbreak in a Eucalyptus woodland. First, we established the trophic roles of the parasitoids through a species-specific multiplex PCR approach on mummies from which parasitoids emerged. Then, we assessed host-parasitoid density relationships across three spatial scales (leaf, tree and site) over one year. We detected four endoparasitoid species of the family Encyrtidae (Hymenoptera); two primary parasitoid and one heteronomous hyperparasitoid Psyllaephagus species (the latter with female development as a primary parasitoid and male development as a hyperparasitoid), and the hyperparasitoid Coccidoctonus psyllae. Parasitoid development was host-synchronized, although synchrony between sites appeared constrained during winter (due to temperature differences). Parasitization was predominantly driven by one primary parasitoid species and was mostly inversely host-density dependent across the spatial scales. Hyperparasitization by C. psyllae was psyllid-density dependent at the site scale, however, this only impacted the rarer primary parasitoid. High larval parasitoid mortality due to density-dependent nymphal psyllid mortality (a consequence of resource limitation) compounded by a summer heat wave was incorporated in the assessment and resulted in density independence of host-parasitoid relationships. As such, high larval parasitoid mortality during insect herbivore outbreaks may contribute to the absence of host density-dependent parasitization during outbreak events. © 2017 Institute of Zoology, Chinese Academy of Sciences.

  5. The effectiveness of habitat modification schemes for enhancing beneficial insects: Assessing the importance of trap cropping management approach

    Science.gov (United States)

    Trisnawati, Indah; Azis, Abdul

    2017-06-01

    Many farms in regions of intensive crop production lack the habitats that historically provided resources to beneficial insects, and this lack has compromised the ability of farmers to rely on natural enemies for pest control. One of the strategies to boost populations of existing or naturally occurring beneficial insects is to supply them with appropriate habitat and alternative food sources, such as diversifying trap crop systems and plant populations in or around fields include perennials and flowering plants. Trap cropping using insectary plant that attracts beneficial insects as natural enemies, especially flowering plants, made for provision of habitat for predators or parasitoids that are useful for biological control. Perimeter trap cropping (PTC) is a method of integrated pest management in which the main crop is surrounded with a perimeter trap crop that is more attractive to pests. We observed PTC habitat modification and conventionaly-managed tobacco farms in Purwosari Village, Pasuruan (East Java) to evaluate the effectiveness of habitat modification management prescription (perimeter trap crop using flowering plant Crotalaria juncea) on agroecosystem natural enemies. Field tests were conducted in natural enemies (predator and parasitoid) abundance dynamic and diversity on tobacco field in Purwoasri, Pasuruan. Yellow pan trap, sweep net and hand collecting methods were applied in each 10 days during tobacco growth stage (vegetative, generative until reproductive/harvesting. The results showed that application perimeter trap crop with C. juncea in tobacco fields able to help arthropod conservation of natural enemies on all tobacco growth stages. These results were evidenced the increase in abundance of predators and parasitoids and the increased value of the Diversity Index (H') and Evenness Index (EH) in all tobacco growth phases. Composition of predator and parasitoid in the habitat modification field were more diverse than in the conventional field

  6. 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.

  7. Inhibition of predator attraction to kairomones by non-host plant volatiles for herbivores: a bypass-trophic signal.

    Directory of Open Access Journals (Sweden)

    Qing-He Zhang

    Full Text Available BACKGROUND: Insect predators and parasitoids exploit attractive chemical signals from lower trophic levels as kairomones to locate their herbivore prey and hosts. We hypothesized that specific chemical cues from prey non-hosts and non-habitats, which are not part of the trophic chain, are also recognized by predators and would inhibit attraction to the host/prey kairomone signals. To test our hypothesis, we studied the olfactory physiology and behavior of a predaceous beetle, Thanasimus formicarius (L. (Coleoptera: Cleridae, in relation to specific angiosperm plant volatiles, which are non-host volatiles (NHV for its conifer-feeding bark beetle prey. METHODOLOGY/PRINCIPAL FINDINGS: Olfactory detection in the clerid was confirmed by gas chromatography coupled to electroantennographic detection (GC-EAD for a subset of NHV components. Among NHV, we identified two strongly antennally active molecules, 3-octanol and 1-octen-3-ol. We tested the potential inhibition of the combination of these two NHV on the walking and flight responses of the clerid to known kairomonal attractants such as synthetic mixtures of bark beetle (Ips spp. aggregation pheromone components (cis-verbenol, ipsdienol, and E-myrcenol combined with conifer (Picea and Pinus spp. monoterpenes (alpha-pinene, terpinolene, and Delta(3-carene. There was a strong inhibitory effect, both in the laboratory (effect size d = -3.2, walking bioassay and in the field (d = -1.0, flight trapping. This is the first report of combining antennal detection (GC-EAD and behavioral responses to identify semiochemical molecules that bypass the trophic system, signaling habitat information rather than food related information. CONCLUSIONS/SIGNIFICANCE: Our results, along with recent reports on hymenopteran parasitoids and coleopteran predators, suggest that some NHV chemicals for herbivores are part of specific behavioral signals for the higher trophic level and not part of a background noise. Such bypass

  8. The physics of pollinator attraction.

    Science.gov (United States)

    Moyroud, Edwige; Glover, Beverley J

    2017-10-01

    Contents 350 I. 350 II. 350 III. 352 IV. 353 V. 353 353 References 354 SUMMARY: This Tansley Insight focuses on recent advances in our understanding of how flowers manipulate physical forces to attract animal pollinators and ensure reproductive success. Research has traditionally explored the role of chemical pigments and volatile organic compounds as cues for pollinators, but recent reports have demonstrated the importance of physical and structural means of pollinator attraction. Here we explore the role of petal microstructure in influencing floral light capture and optics, analysing colour, gloss and polarization effects. We discuss the interaction between flower, pollinator and gravity, and how petal surface structure can influence that interaction. Finally, we consider the role of electrostatic forces in pollen transfer and pollinator attraction. We conclude that this new interdisciplinary field is evolving rapidly. © 2016 The Authors. New Phytologist © 2016 New Phytologist Trust.

  9. The attractiveness of car use

    NARCIS (Netherlands)

    Bleijenberg, A.N.

    2012-01-01

    Understanding the driving forces behind car use is necessary for the development of effective transport policies. The high door-to-door speed of the car in comparison with other travel modes forms its main attractiveness. And speed is the main engine for mobility growth, which is not easy to curb.

  10. THE INFLUENCE OF CULTURAL PRACTICE ON POPULATION OF PEA LEAFMINER (Liriomyza huidobrensis AND ITS PARASITOIDS IN POTATO

    Directory of Open Access Journals (Sweden)

    Ida Bagus Gde Suryawan

    2016-10-01

    Full Text Available Pea leafminer (Liriomyza huidobrensis is the major pest of potato crop in Indonesia. The use of insecticides to control the pest is ineffective and harmful to the natural enemies. The study aimed to find out a promising cultural practice for leafminer management on potato crop. The study was conducted at a farmer’s field in Bali in 2004. Potato plants (Granola variety were grown in a raised-bed plot of 10 m x 1 m. The treatments evaluated were standard cultural practice (C, C plus reflective plastic mulch (RPM (CM, farmer’s practice (F, vermicompost (V, and V plus RPM (VM. All treatments were arranged in RCBD with five replications. From each plot, 10 plant samples were randomly taken to observe the presence of larvae, mines, and adults. Larvae and adults of leafminer and mines were separately counted from the top, middle, and bottom parts of the plant samples. Parasitoids were collected from the infested leaves of the plant samples. Emerged parasitoids were counted and put into vials with 70% ethyl alcohol and then identified. The results showed that the population of adults, larvae of L. huidobrensis, and mines were less in C, CM, V, and VM treatments compared to farmer's practice (F. However, RPM (CM and VM treatments significantly reduced population of leafminer and mines. The highest population of adults, larvae, and mines on RPM treatment were less than 1.5, 8.5, and 10 per plant, respectively compared to other treatments which were greater than 3.2 for adults, 12.4 for larvae, and 12.7 for mines. Parasitoid population and parasitism level were more in vermicompost treatments (V and VM compared to other treatments (C, CM, and F. The results showed that application of pesticides was ineffective against leafminer and reduced parasitoid population; in the other hand RPM was effective to control leafminer although the effect on parasitoids was not clear. Parasitoid species that were found associated with potato crop were Hemiptarsenus

  11. Permanence and chaos in a host-parasitoid model with prolonged diapause for the host

    Science.gov (United States)

    Zhao, Min; Zhang, Limin

    2009-12-01

    The dynamic behavior of a host-parasitoid model with prolonged diapause for the host is investigated. It is proved that the system is permanent under certain appropriate conditions. Numerical simulations are presented to illustrate consistency with the theoretical analysis. For the biologically reasonable range of parameter values, the global dynamics of the system have been studied numerically. In particular, the effect of prolonged diapause on the system has been investigated. Many forms of complex dynamics are observed, including quasi-periodicity, period-doubling and period-halving bifurcations, chaotic bands with periodic windows, attractor crises, intermittency, and supertransients. These complex dynamic behaviors are confirmed by the largest Lyapunov exponents.

  12. Preferência hospedeira do parasitoide de ovos Trichogramma pretiosum Host preference of the egg parasitoid Trichogramma pretiosum

    Directory of Open Access Journals (Sweden)

    Jullyana Rodrigues Siqueira

    2012-01-01

    Full Text Available O sucesso das liberações de Trichogramma spp. depende basicamente do conhecimento das características bioecológicas do parasitoide e da sua interação com o hospedeiro alvo. Assim, o objetivo deste trabalho foi avaliar a preferência hospedeira de T. pretiosum entre os ovos de S. frugiperda, S. albula, S. eridania, A. gemmatalis, P. includens, D. saccharalis e A. kuehniella. Para os testes de preferência, foram instaladas arenas com garrafas de polietileno e, em cada uma delas, foi colocada uma cartela com ovos de duas espécies de hospedeiros e uma fêmea do parasitoide por 24 horas. Os parâmetros avaliados foram o parasitismo (% e a emergência (%. As fêmeas de T. pretiosum apresentaram preferência pelos ovos de A. kuehniella. No entanto, nos ensaios com A. gemmatalis X P. includens e D. saccharalis X S. frugiperda, não ocorreram diferenças no parasitismo. Assim, pode-se afirmar que, nos teste de livre escolha, na ausência do hospedeiro em que os parasitoides foram multiplicados (A. kuehniella, as fêmeas não apresentaram preferência ao parasitismo, o que indica a existência de condicionamento pré-imaginal do parasitoide. Os resultados da viabilidade dos ovos parasitados por T. pretiosum variaram entre os diferentes hospedeiros testados.The success of Trichogramma spp. releases in biological control programs relies upon the knowledge of the parasitoid bio-ecological characteristics and the parasitoid interaction with the target pest. Therefore, this research aimed to evaluate T. pretiosum host preference among eggs of S. frugiperda, S. albula, S. eridania, A. gemmatalis, P. includens, D. saccharalis and A. kuehniella. Polyethylene cages were set to test host preference of T. pretiosum comparing each two groups of host species. The evaluated parameter was parasitism (% and parasitoid emergence (%. T. pretiosum females parasitized preferably A. kuehniella eggs. However, in the bioassay with A. gemmatalis X P. includens and D

  13. Elevated O3 increases volatile organic compounds via jasmonic acid pathway that promote the preference of parasitoid Encarsia formosa for tomato plants.

    Science.gov (United States)

    Cui, Hongying; Wei, Jianing; Su, Jianwei; Li, Chuanyou; Ge, Feng

    2016-12-01

    The elevated atmospheric O3 level may change the interactions of plants and insects, which potentially affects direct and indirect plant defences. However, the underlying mechanism of the impact of elevated O3 on indirect plant defence, namely the efficacy of natural enemies, is unclear. Here we tested a hypothesis that linked the effects of elevated O3 and whitefly herbivory on tomato volatile releases mediated by the jasmonic acid (JA) pathway with the preferences of parasitoid Encarsia formosa for two different tomato genotypes (wild-type (Wt) and JA-deficient genotype (spr2)). The O3 and whitefly herbivory significantly increased the production of volatile organic compounds (VOCs), including monoterpenes and green leaf volatiles (GLVs). The Wt plants released higher volatile levels, particularly monoterpenes, than did the spr2 plants. In Y-tube tests, limonene and Z-3-hexanol played key roles in the attraction of E. formosa. Moreover, regardless of plant genotype, the two plant genotypes were preferred by adult E. formosa under the O3 and O3+ herbivory treatments. Our results suggest that under elevated O3, the activation of the JA pathway significantly up-regulates the emission rates of volatiles, through which the efficacy of natural enemy might be promoted. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

  14. Penampilan hama pelipat daun Cnaphalocrosis medinalis imigran dan parasitoid elasmus sp. di pertanaman padi

    Directory of Open Access Journals (Sweden)

    Baehaki Suherlan Effendi

    2017-02-01

    Full Text Available Cnaphalocrosis medinalis (Guenee is a potential rice pest. The research was conducted at Subang district, used randomized block design. The big plot with 80 m x 100 m is planed by Ciherang rice variety. The big plot is divided to two plots with each size 40 m x 100 m. The first plot controlled by fipronil insecticides, but another one do not controlled us untreated plots. The untreated plot is divided to 160 small plots with size 5 m x 5 m. Observation on 30 hills per plot of randomize three plots every weeks. The result of this research show that abundance of larvae and pupae of leap folder on Ciherang variety was bimodel with two peaks. These curve indicated that leaf folder development reach two generation in one season. The relationship curve between rice plant old and leaf damage was linear curve with correlated value was 87%, but relationship curve with correlated value was 95%. The leaf folder more develop on the vegetative phase than on generative phase. The existent of larvae parasitoid, Elasmus sp is very late and abundance began of 70 days rice old with 14.8 % larvae parasitism. In the nearest harvest the larvae parasitism up to 94.4%. Amount of  parasitoid is very high to reach 225 parasitoid per larvae on 70 days rice old. Analog rice growth on dry season 2002 a leaf damage level was 5-50% and effect to yield losses was 833.3 kg/ha grain dry harvested or loosing income was Rp. 1,085,550.

  15. Aphid symbionts and endogenous resistance traits mediate competition between rival parasitoids.

    Science.gov (United States)

    Kraft, Laura J; Kopco, James; Harmon, Jason P; Oliver, Kerry M

    2017-01-01

    Insects use endogenous mechanisms and infection with protective symbionts to thwart attacks from natural enemies. Defenses that target specific enemies, however, potentially mediate competition between rivals and thereby impact community composition. Following its introduction to North America to control pea aphids (Acyrthosiphon pisum), the parasitoid Aphidius ervi competitively displaced other parasitoids, except for the native Praon pequodorum. The pea aphid exhibits tremendous clonal variation in resistance to A. ervi, primarily through infection with the heritable bacterial symbiont Hamiltonella defensa, although some symbiont-free aphid genotypes encode endogenous resistance. Interestingly, H. defensa strains and aphid genotypes that protect against A. ervi, provide no protection against the closely related, P. pequodorum. Given the specificity of aphid defenses, we hypothesized that aphid resistance traits may contribute to the continued persistence of P. pequodorum. We conducted multiparasitism assays to determine whether aphid resistance traits mediate internal competition between these two solitary parasitoid species, but found this was not the case; P. pequodorum was the successful internal competitor across lines varying in susceptibility to A. ervi. Next, to determine whether resistance traits influence competitive interactions resulting in the stable persistence of P. pequodorum, we established replicated cages varying in the proportion of resistant aphids and recorded successful parasitism for each wasp species over time. As expected, A. ervi outcompeted P. pequodorum in cages containing only susceptible aphids. However, P. pequodorum not only persisted, but was the superior competitor in populations containing any proportion (20-100%) of resistant aphids (20-100%). Smaller scale, better replicated competition cage studies corroborated this finding, and no-competition and behavioral assays provide insight into the processes mediating competition

  16. Attracting girls to physics

    Science.gov (United States)

    Borg, Anne; Sui, Manling

    2013-03-01

    Large regional differences remain in the number of girls studying physics and the number of female physicists in academic positions. While many countries struggle with attracting female students to university studies in physics, climbing the academic ladder is the main challenge for these women. Furthermore, for many female physicists the working climate is not very supportive. The workshop Attracting Girls to Physics, organized as part of the 4th IUPAP International Conference on Women in Physics, South Africa 2011, addressed attitudes among education-seeking teenagers and approaches for attracting young girls to physics through successful recruitment plans, including highlighting the broad spectrum of career opportunities for those with physics qualifications. The current paper presents findings, examples of best practices, and recommendations resulting from this workshop.

  17. 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.

  18. Honey and honey-based sugars partially affect reproductive trade-offs in parasitoids exhibiting different life-history and reproductive strategies

    NARCIS (Netherlands)

    Harvey, Jeffrey A.; Essens, Tijl A.; Las, Rutger A.; Veen, van Cindy; Visser, B.; Ellers, J.; Heinen, R.; Gols, R.

    2017-01-01

    Adult dietary regimes in insects may affect egg production, fecundity and ultimately fitness. This is especially relevant in parasitoid wasps where many species serve as important biological control agents of agricultural pests. Here, we tested the effect of honey and sugar diets on daily fecundity

  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

  20. Coffee Berry Insect Pests and their Parasitoids in the Afromontane ...

    African Journals Online (AJOL)

    A study was conducted to investigate the presence, intensity and damages caused to coffee berries by major insect pests of coffee in wild coffee populations in Afromontane rainforests of Southwestern Ethiopia. The parasitoids associated with those insect pests were also studied. Based on ecological descriptions of forest ...

  1. Early entomology and the discovery of insect parasitoids

    NARCIS (Netherlands)

    Lenteren, van J.C.

    2005-01-01

    Developments in the history of entomology until the discovery of insect parasitoids are summarized. Particular attention is paid to the evolution of entomology in China and Europe, and to the emergence of the idea that certain organisms could be used for biological control of pests. The first

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

    NARCIS (Netherlands)

    Silva, e 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

  3. Automictic parthenogenesis in the parasitoid Venturia canescens (Hymenoptera : Ichneumonidae) revisited

    NARCIS (Netherlands)

    Beukeboom, LW; Pijnacker, LP; Traut, W.

    2000-01-01

    Both arrhenotokous and thelytokous reproduction are known to occur in the parasitoid wasp Venturia canescens. The cytological mechanism of thelytoky was previously reported to involve the formation of a restitution metaphase after the reduction division, but the exact nature of the subsequent

  4. Species diversity and activity of parasitoids of the sweetpotato ...

    African Journals Online (AJOL)

    The species range, activity and relative abundance of parasitoids attacking the sweetpotato butterfly, Acraea acerata Hew. (Lepidoptera: Nymphalidae) in Uganda was investigated. Samples of eggs and larvae of the sweetpotato butterfly were collected from some of the major sweetpotato growing districts of Uganda to ...

  5. Diversity of cereal aphid parasitoids in simple and complex landscapes

    NARCIS (Netherlands)

    Vollhardt, I.M.G.; Tscharntke, T.; Wackers, F.L.; Bianchi, F.J.J.A.; Thies, C.

    2008-01-01

    Structurally complex landscapes may enhance local species richness and interactions, which is possibly due to a higher species pool in complex landscapes. This hypothesis was tested using cereal aphid parasitoids (Hymenoptera, Aphidiidae) by comparing 12 winter wheat fields in structurally complex

  6. Natural Enemies of the Coccinellidae: Parasites, Pathogens, and Parasitoids

    Science.gov (United States)

    The purpose of this review is to highlight recent literature on natural enemies that attack lady beetles, both entomophagous and phytophagous species. Information on parasites, pathogens, and parasitoids of the Coccinellidae has accumulated slowly, but gaps in our knowledge of this subject remain. ...

  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

  8. Preventive control of aphids in ornamental plants with complementary parasitoids.

    Science.gov (United States)

    Dassonville, N; Thielemans, T; Ruisinger, M; Rosemeyer, V

    2012-01-01

    Biological control of aphids can be achieved with parasitoids. A parasitoid is a wasp able to parasitize aphids in a host-specific way. These natural enemies of aphids are used in organic or integrated pest management strategies. In order to apply the matching parasitoid against a given aphid species, the aphid has to be detected in the crop and subsequently identified. By the time the aphids are spotted by the grower and then identified by himself or a specialist, it is usually more difficult to gain control over an increasing aphid population. Viridaxis developed a new concept of aphid control, based not on the species identified but on the crop treated. There was a need for a product controlling the largest possible spectrum of aphid species susceptibly present in ornamental crops. As the first step of development, an inventory of the aphid species attacking ornamental crops was made in various regions. A unique cocktail of parasitoids species (OrnaProtect) controlling all these aphids was then developed. OrnaProtect contains six different species of natural aphid enemies, and is able to control all commonly appearing aphids attacking ornamental crops. The fact of mixing different species not only covers the entire spectrum of aphids, but also contributes to prolonged hatching. To reinforce this long lasting emergence, mummies of different ages are mixed, older mummies (stored at low temperature) emerging earlier after release than young mummies. With that prolonged hatching dynamics, a release every two weeks assures a permanent presence of fresh adult parasitoids in the crop. The ready-to-use units of OrnaProtect contain an integrated feeding point which contributes to longevity and efficiency of the parasitoids. Its application in the crop is much faster than even any chemical treatment. Here, we show the results of trials made with OrnaProtect in 2011 on several crops (Hydrangea macrophylla, Solanum jasminoides, Argyranthemum frutescens and Osteospermum

  9. 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

  10. Infection of host plants by Cucumber mosaic virus increases the susceptibility of Myzus persicae aphids to the parasitoid Aphidius colemani.

    Science.gov (United States)

    Mauck, Kerry E; De Moraes, Consuelo M; Mescher, Mark C

    2015-06-04

    Plant viruses can profoundly alter the phenotypes of their host plants, with potentially far-reaching implications for ecology. Yet few studies have explored the indirect, host-mediated, effects of plant viruses on non-vector insects. We examined how infection of Cucurbita pepo plants by Cucumber mosaic virus (CMV) impacted the susceptibility of aphids (Myzus persicae) to attack by the parasitoid wasp Aphidius colemani. In semi-natural foraging assays, we observed higher rates of aphid parasitism on infected plants compared to healthy plants. Subsequent experiments revealed that this difference is not explained by different attack rates on plants differing in infection status, but rather by the fact that parasitoid larvae successfully complete their development more often when aphid hosts feed on infected plants. This suggests that the reduced nutritional quality of infected plants as host for aphids--documented in previous studies--compromises their ability to mount effective defenses against parasitism. Furthermore, our current findings indicate that the aphid diet during parasitoid development (rather than prior to wasp oviposition) is a key factor influencing resistance. These findings complement our previous work showing that CMV-induced changes in host plant chemistry alter patterns of aphid recruitment and dispersal in ways conducive to virus transmission.

  11. Effect of Chemical Ratios of a Microbial-Based Feeding Attractant on Trap Catch of Drosophila suzukii (Diptera: Drosophilidae).

    Science.gov (United States)

    Cha, Dong H; Landolt, Peter J; Adams, Todd B

    2017-08-01

    Drosophila suzukii Matsumura, spotted wing drosophila, can be trapped with a feeding attractant based on wine and vinegar volatiles and consisting of acetic acid, ethanol, acetoin, and methionol. Using that four-component blend, we found that the catch of spotted wing drosophila increased with increases in the release rate of acetoin (from 0.5 mg/d to 34 mg/d) from polyethylene sachet dispensers, and with increases in the concentrations of acetic acid (from 0.25% to 4%) or ethanol (from 0.08% to 2%) when dispensed in the trap drowning solution. However, we saw no increase in spotted wing drosophila trapped with increase of the methionol release rate from 0.4 mg/d to 4.9 mg/d or from 0.19 mg/d to 0.8 mg/d, from sachets. A new formulation based on optimized amounts of these four chemicals yielded a doubling of spotted wing drosophila trapped compared to a previously reported formulation. Further field testing confirmed that the simultaneous increases in the release rate of acetoin from a dispenser and the amount of acetic acid in the trap drowning solution provided the increased spotted wing drosophila trap response to the new formulation. These findings provide a practical means to improve the power of this lure to detect and monitor D. suzukii. Published by Oxford University Press on behalf of Entomological Society of America 2017. This work is written by US Government employees and is in the public domain in the US.

  12. 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

  13. Male killing Spiroplasma protects Drosophila melanogaster against two parasitoid wasps

    Science.gov (United States)

    Xie, J; Butler, S; Sanchez, G; Mateos, M

    2014-01-01

    Maternally transmitted associations between endosymbiotic bacteria and insects are diverse and widespread in nature. Owing to imperfect vertical transmission, many heritable microbes have evolved compensational mechanisms to enhance their persistence in host lineages, such as manipulating host reproduction and conferring fitness benefits to host. Symbiont-mediated defense against natural enemies of hosts is increasingly recognized as an important mechanism by which endosymbionts enhance host fitness. Members of the genus Spiroplasma associated with distantly related Drosophila hosts are known to engage in either reproductive parasitism (i.e., male killing) or defense against natural enemies (the parasitic wasp Leptopilina heterotoma and a nematode). A male-killing strain of Spiroplasma (strain Melanogaster Sex Ratio Organism (MSRO)) co-occurs with Wolbachia (strain wMel) in certain wild populations of the model organism Drosophila melanogaster. We examined the effects of Spiroplasma MSRO and Wolbachia wMel on Drosophila survival against parasitism by two common wasps, Leptopilina heterotoma and Leptopilina boulardi, that differ in their host ranges and host evasion strategies. The results indicate that Spiroplasma MSRO prevents successful development of both wasps, and confers a small, albeit significant, increase in larva-to-adult survival of flies subjected to wasp attacks. We modeled the conditions under which defense can contribute to Spiroplasma persistence. Wolbachia also confers a weak, but significant, survival advantage to flies attacked by L. heterotoma. The host protective effects exhibited by Spiroplasma and Wolbachia are additive and may provide the conditions for such cotransmitted symbionts to become mutualists. Occurrence of Spiroplasma-mediated protection against distinct parasitoids in divergent Drosophila hosts suggests a general protection mechanism. PMID:24281548

  14. 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)

  15. Willingness to Disclose Symptoms to a Male Physician: Effects of the Physician's Physical Attractiveness, Body Area of Symptom and the Patient's Self-Esteem, Locus of Control and Sex.

    Science.gov (United States)

    Young, Jerald W.

    Two experiments involving 49 male and 49 female college students were conducted to determine the effects of physician physical attractiveness on the patients' disclosures of personal information (symptoms). In the first experiment, subjects rated pictures of physicians for physical attractiveness and reported their willingness to disclose and…

  16. Controlling infestation of a chocolate factory by Plodia interpunctella by combining mating disruption and the parasitoid Habrobracon hebetor.

    Science.gov (United States)

    Trematerra, Pasquale; Oliviero, Annachiara; Savoldelli, Sara; Schöller, Matthias

    2017-06-01

    A field experiment of 4 years' duration was carried out to evaluate the efficacy of combining the mating disruption (MD) formulation Dismate ZETA ((9Z,12E)-tetradecadienyl acetate), with the parasitoid Habrobracon hebetor against the Indianmeal moth Plodia interpunctella in a chocolate factory. The experimental period began early in 2011 and ended in late 2014. Begane Dismate dispensers were placed in the facility from 2011 to 2014 and H. hebetor was released in 2014. Pheromone-baited traps were used to monitor the flight activity of the male moths and oviposition Petri dish traps were placed to assess the progeny production of P. interpunctella females. Following the start of MD, a decrease in the number of P. interpunctella males caught in monitoring traps was observed from 2011 to 2013. A further decline in the moth population was noted in 2014, when MD was combined with the release of parasitoids. The presence of larvae in the oviposition cups was occasionally observed throughout the monitoring period, from 2011 to 2014. This study demonstrates that the combined system of MD and parasitoids is an effective and reliable technique that can be used to successfully control P. interpunctella. © 2016 Institute of Zoology, Chinese Academy of Sciences.

  17. 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 heterogeneous traffic, add complexity to the timetable. The risk of spreading initial delays to other trains and parts of the network increases with the level of timetable complexity....

  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. Interactions between the entomopathogenic fungi Beauveria bassiana (Ascomycota: Hypocreales) and the aphid parasitoid Diaeretiella rapae (Hymenoptera: Braconidae) on Myzus persicae (Hemiptera: Aphididae).

    Science.gov (United States)

    Silva, R J; Alencar, J R D C C; Silva, K P; Cividanes, F J; Duarte, R T; Agostini, L T; Polanczyk, R A

    2014-06-01

    The interactions between the entomopathogenic fungus Beauveria bassiana (Balsamo-Crivelli) Vuillemin (Ascomycota: Hypocreales) and the aphid parasitoid Diaeretiella rapae McIntoch (Hymenoptera: Braconidae) were evaluated under laboratory conditions. Nymphs of Myzus persicae Sulzer (Hemiptera: Aphididae) were first exposed to parasitoid females for 24 h and then 0, 24, and 48 h afterwards sprayed with a solution of B. bassiana. Likewise, aphids were also sprayed with B. bassiana and then exposed to parasitoids at 0, 24, and 48 h afterwards. Parasitism rate varied from 13 to 66.5%, and were significantly lower in treatments where the two agents were exposed within a 0-24 h time interval compared with the control (without B. bassiana). Parasitoid emergence was negatively affected in treatments with B. bassiana spraying and subsequent exposure to D. rapae. Decreases in longevity of adult females of the D. rapae F1 generation were observed in treatments with B. bassiana spraying. The application of these two biological control agents can be used in combination on the control of M. persicae, wherein this use requires effective time management to avoid antagonistic interactions.

  20. The potential of parasitoid Hymenoptera as bioindicators of arthropod diversity in agricultural grasslands

    National Research Council Canada - National Science Library

    Annette Anderson; Stephen McCormack; Alvin Helden; Helen Sheridan; Anne Kinsella; Gordon Purvis

    2011-01-01

    .... This study tested the hypothesis that parasitoid Hymenoptera are potential bioindicators that provide a useful means to assess the wider biodiversity of arthropod populations in agro-ecosystem...

  1. KEMELIMPAHAN DAN KERAGAMAN JENIS PARASITOID HAMA PENGGULUNG DAUN PISANG ERIONOTA THRAX L. DI KABUPATEN LAMPUNG SELATAN

    Directory of Open Access Journals (Sweden)

    Lestari Wibowo

    2015-03-01

    Full Text Available The abundance and diversity of the parasitoid of banana leaf skipper pest (Erionota thrax L. in South Lampung Regency. This research was conducted to determine the abundance, diversity, and parasitation ability of several parasitoids of the banana skipper or banana leafroller (Erionota thrax in South Lampung Regency. This research was carried out with a survey method by taking out samples of larvae and pupae of E. thrax in the District of Natar, Jati Agung, and Tanjung Bintang, South Lampung. Results of the survey showed that there were 8 types of parasitoids recovered from larvae or pupae of E. thrax, i.e. Brachymeria lasus (Chalcididae: Hymenoptera, B. thracis (Chalcididae: Hymenoptera, Charops sp. (Ichneumonidae: Hymenoptera, Casinaria sp. (Ichneumonidae: Hymenoptera, Xanthopimpla sp. (Ichneumonidae: Hymenoptera, Cotesia erionotae (Braconidae: Hymenoptera, and two parasitoids Diptera (Tachinidae and Sarcophagidae. The highest abundance of parasitoid was found in Tanjung Bintang with 171 parasitoids (index of diversity (H’ = 1.0256 and index of evenness (E = 0.5724. In Natar District, the abundance of parasitoid was 63 parasitoids, but it had a greater H’ value (1.4396 and E-value (0.7398. Meanwhile, in Jati Agung District, the abundance of parasitoid was 56 individuals but the value of H’ was also high, which was 1.012 with the value of E of 0.6064. The percentages of parasitation to the larvae and pupae E. thrax were 55.01% (Tanjung Bintang District, 31.68% (Natar District and 33.34% (Jati Agung District.

  2. Stress-reducing effects of indoor plants in the built healthcare environment : The mediating role of perceived attractiveness

    NARCIS (Netherlands)

    Dijkstra, K.; Pieterse, Marcel E.; Pruyn, A.Th.

    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

  3. Stress-reducing effects of indoor plants in the built healthcare environment: The mediating role of perceived attractiveness

    NARCIS (Netherlands)

    Dijkstra, K.; Pieterse, Marcel E.; Pruyn, Adriaan T.H.

    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

  4. The effect of microscopic attractive interactions on piezoelectric coefficients of nanoscale DNA films and its resultant mirocantilever-based biosensor signals

    Science.gov (United States)

    Wu, Jun-Zheng; Zhou, Mei-Hong; Zhang, Neng-Hui

    2017-10-01

    The adsorption of charged biomolecules on a substrate will trigger a self-induced electric potential field that could deflect microcantilever biosensors in the nanometer regime. The paper is devoted to a multiscale characterization of the piezoelectric coefficient of double-stranded DNA (dsDNA) films with microscopic attractive interactions in multivalence salt solutions, which has a close relationship with biosensor signals. First, two different analytical models of cantilever deflections based on macroscopic piezoelectric theories or mesoscopic liquid crystal theories were combined in the sense of equivalent deformation in order to bridge the relation between the macroscopic piezoelectric coefficient of an adsorbate film and the sensitivity of its microstructure to surrounding conditions. Second, two interaction potentials of the free energy for repulsion-dominated DNA films in NaCl solution or attraction-repulsion-coexisted DNA films in multivalent salt solutions were used to compare the piezoelectric effect and the resultant cantilever deformation at various packing conditions, such as different packing density, various nucleotide numbers and two packing technologies, i.e. nano-grafting or self-assembling technology. The variational tendency of microcantilever deflections predicted by the present multiscale analytical model agrees well with the related DNA-mirocantilever experiments. Negative piezoelectric coefficient of dsDNA film exists in multivalent salt solutions, and its distinctive size effect with different packing densities and nucleotide numbers provides us with an opportunity to obtain a more sensitive microcantilever sensor by careful control of packing conditions.

  5. The Effects of Light and Height of Building in AttractingPaederus fuscipesCurtis to Disperse towards Human Residential Areas.

    Science.gov (United States)

    Maryam, Sufian; Fadzly, Nik; Zuharah, Wan Fatma

    2016-11-01

    Paederus fuscipes Curtis is a nocturnal insect. The attractiveness of artificial light sources from residential premises eventually causes the risk of severe dermatitis effect, once Paederus is in contact with human skin. The objective of this study is to investigate whether the light and height factors of residential buildings and its' association to rice cultivation phases are primary reasons for P. fuscipes 's mass dispersal into human residential areas. The study site was located in residential premises that were built adjacent to rice field areas (≈ 32-60 m and 164 m) north of the rice field located in Teluk Air Tawar, mainland of Pulau Pinang. Overall, both light sources and rice cultivation phases caused a significant effect for P. fuscipes beetles dispersal flight to invade human settlements. More P. fuscipes were captured near the bright light source with the highest number of beetles found during harvesting stage. Whereas, significantly higher number of P. fuscipes were captured at level 2 and 3 compared to ground and level 1 of the apartment building and P. fuscipes was also found significantly affected by the rice cultivation phases at different elevation levels. This indicates that bright light sources and higher elevation levels are the main factors in attracting P. fuscipes beetles to disperse and causes infestations in residential areas. This finding could create awareness among the public on P. fuscipes dispersal pattern.

  6. Oceanic signals in rapid polar motion: results from a barotropic forward model with explicit consideration of self-attraction and loading effects

    Science.gov (United States)

    Schindelegger, Michael; Quinn, Katherine J.; Ponte, Rui M.

    2017-04-01

    Numerical modeling of non-tidal variations in ocean currents and bottom pressure has played a key role in closing the excitation budget of Earth's polar motion for a wide range of periodicities. Non-negligible discrepancies between observations and model accounts of pole position changes prevail, however, on sub-monthly time scales and call for examination of hydrodynamic effects usually omitted in general circulation models. Specifically, complete hydrodynamic cores must incorporate self-attraction and loading (SAL) feedbacks on redistributed water masses, effects that produces ocean bottom pressure perturbations of typically about 10% relative to the computed mass variations. Here, we report on a benchmark simulation with a near-global, barotropic forward model forced by wind stress, atmospheric pressure, and a properly calculated SAL term. The latter is obtained by decomposing ocean mass anomalies on a 30-minute grid into spherical harmonics at each time step and applying Love numbers to account for seafloor deformation and changed gravitational attraction. The increase in computational time at each time step is on the order of 50%. Preliminary results indicate that the explicit consideration of SAL in the forward runs increases the fidelity of modeled polar motion excitations, in particular on time scales shorter than 5 days as evident from cross spectral comparisons with geodetic excitation. Definite conclusions regarding the relevance of SAL in simulating rapid polar motion are, however, still hampered by the model's incomplete domain representation that excludes parts of the highly energetic Arctic Ocean.

  7. 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.

  8. Developing Cotton IPM by Conserving Parasitoids and Predators of The Main Pest

    Directory of Open Access Journals (Sweden)

    Nurindah Nurindah

    2015-09-01

    Full Text Available On early development of intensive cotton program, insect pests were considered as an important aspect in cotton cultivation, so that it needed to be scheduled sprays. The frequency of sprays was 7 times used 12L of chemical insecticides per hectare per season. Development of cotton IPM was emphasized on non-chemical control methods through optimally utilize natural enemies of the cotton main pests (Amrasca biguttulla (IshidaHelicoverpa armigera (Hübner. Conservation of parasitoids and predators by providing the environment that support their population development is an act of supporting the natural enemies as an effective biotic mortality factor of the insect pests. The conservation could be done by improving the plant matter and cultivation techniques that include the use of resistant variety to leafhopper, intercropping cotton with secondary food plants, mulch utilization, using action threshold that considered the presence of natural enemies, and application of botanical insecticides, if needed. Conservation of parasitoids and predators in cotton IPM could control the insect pests without any insecticide spray in obtaining the production of cotton seed. As such, the use of IPM method would increase farmers’ income.

  9. 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.

  10. Ecosystem-Based Incorporation of Nectar-Producing Plants for Stink Bug Parasitoids.

    Science.gov (United States)

    Tillman, Glynn

    2017-06-24

    Adult parasitoids of pest insects rely on floral resources for survival and reproduction, but can be food-deprived in intensively managed agricultural systems lacking these resources. Stink bugs are serious pests for crops in southwest Georgia. Provisioning nectar-producing plants for parasitoids of stink bugs potentially can enhance biocontrol of these pests. Knowledge of spatial and temporal availability and distribution of stink bugs in host plants is necessary for appropriate timing and placement of flowering plants in agroecosystems. Stink bugs move between closely associated host plants throughout the growing season in response to deteriorating suitability of their host plants. In peanut-cotton farmscapes, stink bugs develop in peanut, and subsequently the adults disperse into adjacent cotton. Parasitism of Nezara viridula (L.) adults by Trichopoda pennipes (F.) at the peanut-cotton interface was significantly higher in cotton with a strip of milkweed or buckwheat between the two crops than in cotton alone. Milkweed and buckwheat also provided nectar to a wide range of insect pollinators. Monarch butterflies fed on milkweed. When placed between peanut and cotton, a strip of soybean was an effective trap crop for cotton, reducing economic damage. Incorporation of buckwheat near soybean enhanced parasitism of Euschistus servus (Say) eggs by Telenomus podisi Ashmead in cotton. In conclusion, nectar provision enhances biocontrol of stink bugs, acts together with other management tactics for stink bug control, and aids in conservation of natural enemies, insect pollinators, and the monarch butterfly.

  11. Ecosystem-Based Incorporation of Nectar-Producing Plants for Stink Bug Parasitoids

    Directory of Open Access Journals (Sweden)

    Glynn Tillman

    2017-06-01

    Full Text Available Adult parasitoids of pest insects rely on floral resources for survival and reproduction, but can be food-deprived in intensively managed agricultural systems lacking these resources. Stink bugs are serious pests for crops in southwest Georgia. Provisioning nectar-producing plants for parasitoids of stink bugs potentially can enhance biocontrol of these pests. Knowledge of spatial and temporal availability and distribution of stink bugs in host plants is necessary for appropriate timing and placement of flowering plants in agroecosystems. Stink bugs move between closely associated host plants throughout the growing season in response to deteriorating suitability of their host plants. In peanut-cotton farmscapes, stink bugs develop in peanut, and subsequently the adults disperse into adjacent cotton. Parasitism of Nezara viridula (L. adults by Trichopoda pennipes (F. at the peanut-cotton interface was significantly higher in cotton with a strip of milkweed or buckwheat between the two crops than in cotton alone. Milkweed and buckwheat also provided nectar to a wide range of insect pollinators. Monarch butterflies fed on milkweed. When placed between peanut and cotton, a strip of soybean was an effective trap crop for cotton, reducing economic damage. Incorporation of buckwheat near soybean enhanced parasitism of Euschistus servus (Say eggs by Telenomus podisi Ashmead in cotton. In conclusion, nectar provision enhances biocontrol of stink bugs, acts together with other management tactics for stink bug control, and aids in conservation of natural enemies, insect pollinators, and the monarch butterfly.

  12. Parasitoid Diaeretiella rapae (Hymenoptera: Braconidae) Adjusts Reproductive Strategy When Competing for Hosts.

    Science.gov (United States)

    Kant, Rashmi; Minor, Maria A

    2017-06-01

    Parasitoid fitness depends on its ability to manipulate reproductive strategies when in competition. This study investigated the parasitism and sex allocation strategies of the parasitic wasp Diaeretiella rapae McIntosh at a range of host (Brevicoryne brassicae L.) and conspecific densities. The results suggest that D. rapae females adjust their progeny production and progeny sex ratio with changing competition. When foraging alone, female D. rapae parasitize larger number of B. brassicae nymphs when the number of available hosts is increased, but the overall proportion of parasitized hosts decreases with increase in host density. The proportion of female offspring also decreases with elevated host density. Increase in the number of female D. rapae foraging together increased total parasitism, but reduced relative contribution of each individual female. The number of female progeny decreased when multiple females competed for the same host. However, foraging experience in the presence of one or more conspecifics increased the parasitism rate and proportion of female progeny. Competing females were more active during oviposition and had shorter lives. The study suggests that both host and foundress (female parasitoid) densities have significant effect on progeny production, sex allocation, and longevity of foraging females. © The Authors 2017. Published by Oxford University Press on behalf of Entomological Society of America. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

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

    Directory of Open Access Journals (Sweden)

    Jankowska Beata

    2016-06-01

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

  14. Perceptual adaptation affects attractiveness of female bodies.

    Science.gov (United States)

    Winkler, Christopher; Rhodes, Gillian

    2005-05-01

    We investigated whether short durations (5 minutes) of exposure to distorted bodies can change subsequent perceptions of attractiveness and normality. Participants rated 110 female bodies, varying in width, on either their attractiveness or normality before and after exposure to either extremely narrow (-50% of original width in Experiments 1 and 2) or extremely wide bodies (+50% of original width in Experiment 1, and +70% of original width in Experiment 2). In both experiments, the most attractive and most normal looking bodies became significantly and substantially narrower after exposure to narrow bodies. The most normal looking body changed significantly after exposure to wide bodies, but the most attractive body did not. These results show that perceptions of body attractiveness can be influenced by experience, but that there is an asymmetry between the effects of exposure to narrow and wide bodies. We consider a possible mechanism for this unexpected asymmetry, as well as possible implications for the effects of media exposure on body-image. The most attractive body shape was consistently narrower than the most normal looking body shape. Substantial changes in what looked normal were accompanied by congruent changes in what looked attractive, suggesting that a normal or average body shape may function as a reference point against which body attractiveness is judged.

  15. 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.

  16. Egg parasitoids of Edessa meditabunda (Fabricius (Pentatomidae in lettuce crop

    Directory of Open Access Journals (Sweden)

    Bruna M. Favetti

    2013-06-01

    Full Text Available Egg parasitoids of Edessa meditabunda (Fabricius (Pentatomidae in lettuce crop. This study evaluated the occurrence of parasitoids in eggs of the stink bug, Edessa meditabunda (Fabricius, 1794 (Heteroptera, Pentatomidae found on lettuce crop in Mato Grosso State, Brazil. Samples were collected in the vegetable garden "Cheiro Verde", in the municipality of Tangará da Serra, in curly lettuce. A bed of lettuce was selected randomly, where the eggs of E. meditabunda were collected. Five-hundred and seventy eight eggs of E. meditabunda were collected, 86.3% of them parasitized by Telenomus podisi Ashmead, 1893 (Hymenoptera, Platygastridae, Trissolcus urichi Crawford, 1913 (Hymenoptera, Platygastridae and Neorileya albipes Girault, 1913 (Hymenoptera, Eurytomidae, representing respectively 57.0%, 38.2% and 4.8% of the emerged individuals. This is the first record of these three species parasitizing eggs of E. meditabunda in lettuce.

  17. Attracting attention. Posters.

    Science.gov (United States)

    1998-01-01

    Posters are useful in health education campaigns for announcing events, reinforcing messages communicated through other media, and providing a starting point for discussion. Posters should be clear enough to be understood on their own, sufficiently striking to attract attention, and displayed in places where they will be seen by the target population. The posters should be changed regularly or people will stop noticing them. All posters should be carefully planned and pretested with the intended target group. Use of color can help ensure that figures and symbols stand out from the background and lower case letters are easier to read than all capital letters. Finally, the lettering should be neat and even.

  18. 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.

  19. Laterally Transferred Gene Recruited as a Venom in Parasitoid Wasps

    Science.gov (United States)

    Martinson, Ellen O.; Werren, John H.

    2016-01-01

    Parasitoid wasps use venom to manipulate the immunity and metabolism of their host insects in a variety of ways to provide resources for their offspring. Yet, how genes are recruited and evolve to perform venom functions remain open questions. A recently recognized source of eukaryotic genome innovation is lateral gene transfer (LGT). Glycoside hydrolase family 19 (GH19) chitinases are widespread in bacteria, microsporidia, and plants where they are used in nutrient acquisition or defense, but have previously not been known in metazoans. In this study, a GH19 chitinase LGT is described from the unicellular microsporidia/Rozella clade into parasitoid wasps of the superfamily Chalcidoidea, where it has become recruited as a venom protein. The GH19 chitinase is present in 15 species of chalcidoid wasps representing four families, and phylogenetic analysis indicates that it was laterally transferred near or before the origin of Chalcidoidea (∼95 Ma). The GH19 chitinase gene is highly expressed in the venom gland of at least seven species, indicating a role in the complex host manipulations performed by parasitoid wasp venom. RNAi knockdown in the model parasitoid Nasonia vitripennis reveals that—following envenomation—the GH19 chitinase induces fly hosts to upregulate genes involved in an immune response to fungi. A second, independent LGT of GH19 chitinase from microsporidia into mosquitoes was also found, also supported by phylogenetic reconstructions. Besides these two LGT events, GH19 chitinase is not found in any other sequenced animal genome, or in any fungi outside the microsporidia/Rozella clade. PMID:26715630

  20. Men's attraction to women's bodies changes seasonally.

    Science.gov (United States)

    Pawlowski, Bogusław; Sorokowski, Piotr

    2008-01-01

    Humans exhibit seasonal variation in hormone levels, behaviour, and perception. Here we show that men's assessments of women's attractiveness change also seasonally. In five seasons (from winter 2004 to winter 2005) 114 heterosexual men were asked to assess the attractiveness of the same stimuli: photos of a female with three different waist-to-hip ratios; photos of female breasts, and photos of average-looking faces of young women. For each season, the scores given to the stimuli of the same category (body shape, breast, and face) were combined. Friedman's test revealed significant changes for body shape and breast attractiveness assessments across the seasons, but no changes for face ratings. The highest scores for attractiveness were given in winter and the lowest in summer. We suggest that the observed seasonality is related to the well-known 'contrast effect'. More frequent exposure to women's bodies in warmer seasons might increase men's attractiveness criteria for women's body shape and breasts.

  1. Fatal attraction: the effects of mortality salience on evaluations of charismatic, task-oriented, and relationship-oriented leaders.

    Science.gov (United States)

    Cohen, Florette; Solomon, Sheldon; Maxfield, Molly; Pyszczynski, Tom; Greenberg, Jeff

    2004-12-01

    A study was conducted to assess the effects of mortality salience on evaluations of political candidates as a function of leadership style. On the basis of terror management theory and previous research, we hypothesized that people would show increased preference for a charismatic political candidate and decreased preference for a relationship-oriented political candidate in response to subtle reminders of death. Following a mortality-salience or control induction, 190 participants read campaign statements by charismatic, task-oriented, and relationship-oriented gubernatorial candidates; evaluated their preferences for each candidate; and voted for one of them. Results were in accord with predictions. The theoretical and practical implications of these findings are considered.

  2. Efficacy of aqueous extracts of black alder (Alnus glutinosa GAERTN. and black elderberry (Sambucus nigra L. in reducing the occurrence of Phyllotreta spp., some lepidopteran pests and diamondback moth parasitoids on white cabbage

    Directory of Open Access Journals (Sweden)

    Jankowska Beata

    2016-12-01

    Full Text Available The insecticidal and antifeedant effects of aqueous extracts from two common plants (black alder Alnus glutinosa and black elderberry Sambucus nigra on the occurrence of flea beetles (Phyllotreta spp., as well as lepidopteran pests like the diamondback moth Plutella xylostella, small white butterfly Pieris rapae, large white butterfly Pieris brassicae, cabbage moth Mamestra brassicae and the Plutella xylostella parasitoid complex were investigated on white cabbage in 2008-2009. Aqueous extracts of black elderberry Sambucus nigra significantly reduced numbers of flea beetles Phyllotreta spp., eggs of Pieris rapae and P. brassicae, and larvae and pupae of Plutella xylostella on the cabbage. The aqueous extract of Alnus glutinosa was less effective. Parasitoids had the greatest impact on reducing numbers of diamondback moth: the dominant species was Diadegma fenestralis. The smallest number of parasitoids was reared from pupae collected from plots where the cabbages had been sprayed with the Sambucus nigra extract.

  3. Investment Attractiveness of Food Industries in Ukraine

    Directory of Open Access Journals (Sweden)

    L. О.

    2017-02-01

    Full Text Available Effective investment is a factor for long-term company development. As enhancement of investment attractiveness is a required condition for economic growth and improvement of living standards, it needs to be on the agenda at government and company level. The article’s objective is to study investment attractiveness of food industries in Ukraine over 2012–2015. Investment attractiveness of food industries can be measured by indicators of liquidity, financial sustainability, and profit rate. Basically, food industries in Ukraine are attractive for investment, which is demonstrated by assessment of the financial indicators. The investment attractiveness worsened slightly in 2015 compared with 2014. The essential problems faced by food industries are shortage of internal funds and negative profit rate of all the activities, assets and own capital. Official statistical data and software package SPSS are used to build the dendrogram, allowing for dividing food industries by level of investment attractiveness into three groups: industries with high, medium and low level of investment attractiveness. It is found that meat industry is the one with the highest level of investment attractiveness. Also, investors should look positively at food-canning industry, oil and animal fat industry, flour-milling industry, starch and starch products industry, and other foods industry.

  4. Effects of sex and sexual orientation on self-reported attraction and viewing times to images of men and women: testing for category specificity.

    Science.gov (United States)

    Lippa, Richard A

    2012-02-01

    In a paradigm that asked participants to rate the sexual attractiveness of male and female swimsuit models, Lippa, Patterson, and Marelich (2010) showed that heterosexual men's category specificity exceeded heterosexual women's in two ways: (1) Heterosexual men showed much larger differences in their attraction and viewing times to male versus female photo models than heterosexual women, and (2) heterosexual men's attractions to female but not male models increased with model attractiveness whereas heterosexual women's attractions to both sexes increased with model attractiveness. The current study used the same paradigm to study category specificity in homosexual and heterosexual participants. In addition to replicating previous findings for heterosexual men and women, the results showed that homosexual men were high on category specificity, like heterosexual men, whereas lesbians showed lower levels of category specificity than men, but sometimes higher levels than heterosexual women.

  5. Remedies for a high incidence of broken eggs in furnished cages: effectiveness of increasing nest attractiveness and lowering perch height.

    Science.gov (United States)

    Tuyttens, F A M; Struelens, E; Ampe, B

    2013-01-01

    Two remedial treatments to reduce the high incidence of broken eggs in the furnished cages of our experimental layer farm were investigated: lining the nest floor with artificial turf (to increase nest acceptance) and lowering perch height (to reduce the chance of egg breakage of outside-nest eggs). A 2 × 2 factorial design was used with low (7 cm) or high (24 cm) perches, and with nest floors lined with artificial turf or plastic mesh. Eight cages, each housing 8 hens initially (aged 40 to 56 wk), were used per treatment. Egg location and percentage of broken eggs were recorded. Hen position (cage floor, nest, or perch) was recorded by direct scan-sampling observations. In addition, 8 cages (4 high + 4 low) each containing 8 hens (aged 54 to 56 wk) were videorecorded to determine perch use and behavior during the light period. Data were mainly analyzed using logistic regression and mixed models with cage as the experimental unit. Nest floor material did not influence the percentage of eggs broken or laid outside the nest. The proportion of outside-nest eggs (2.6 vs. 10.6%, P = 0.004), and consequently also of total eggs (2 vs. 4.6%, P = 0.016) broken, was lower for low than high cages. Perch use increased during the observation period, more so for the high cages during the light period and the low cages during the dark period. Perch bout duration (P nest floor lining with artificial turf was not an effective remedy for the already-high rate of broken eggs, but the prevalence of broken outside-nest eggs was lower in cages with low versus high perches. However, perching behavior during the light period was more disturbed in cages with low perches.

  6. Agreement attraction in Serbian: decomposing markedness

    OpenAIRE

    Ristić, Bojana; Molinaro, Nicola; Mancini, Simona

    2016-01-01

    Published online 18 July 2016 Asymmetric number attraction effects have been typically explained via a privative markedness account: plural nouns are more marked than singular ones and thus stronger attractors. However, this account does not explain results from tripartite systems, in which a third number value is available, like paucal. Here we tested whether attraction effects can be driven by specific markedness sub-components, such as frequency/naturalness of use, using Serbian, in whi...

  7. Life-history evolution in hymenopteran parasitoids the roles of host and climate

    NARCIS (Netherlands)

    Askari Seyahooei, Majeed

    2010-01-01

    In this thesis I studied the relationships between parasitoids, hosts and climate from an evolutionary point of view by using hymenopteran parasitoids as a model system. A comparative approach was used to study the variation in life-history traits of species or populations from different habitats. I

  8. The use of oviposition-induced plant cues by Trichogramma egg parasitoids

    NARCIS (Netherlands)

    Pashalidou, F.G.; Huigens, M.E.; Dicke, M.; Fatouros, N.E.

    2010-01-01

    1. Female parasitoids have evolved various foraging strategies in order to find suitable hosts. Egg parasitoids have been shown to exploit plant cues induced by the deposition of host eggs. 2. The tiny wasp Trichogramma brassicae uses oviposition-induced cues from Brussels sprouts to locate eggs of

  9. Herbivore-induced plant volatiles mediate in-flight host discrimination by parasitoids

    NARCIS (Netherlands)

    Fatouros, N.E.; van Loon, J.J.A.; Hordijk, C.A.; Smid, H.M.; Dicke, M.

    2005-01-01

    Herbivore feeding induces plants to emit volatiles that are detectable and reliable cues for foraging parasitoids, which allows them to perform oriented host searching. We investigated whether these plant volatiles play a role in avoiding parasitoid competition by discriminating parasitized from

  10. Nutritional integration between insect hosts and koinobiont parasitoids in an evolutionary framework

    NARCIS (Netherlands)

    Harvey, Jeffrey A.; Malčická, Mima

    Mark Jervis was one of the world's foremost experts on life history and development strategies in parasitoids. He held a special place for the nutritional ecology of immature and adult parasitoids; his work on adult nutritional ecology and reproduction is considered seminal. Here, we discuss aspects

  11. 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.

  12. Parasitoid diversity reduces the variability in pest control services across time on farms

    Science.gov (United States)

    Macfadyen, Sarina; Craze, Paul G.; Polaszek, Andrew; van Achterberg, Kees; Memmott, Jane

    2011-01-01

    Recent declines in biodiversity have increased interest in the link between biodiversity and the provision and sustainability of ecosystem services across space and time. We mapped the complex network of interactions between herbivores and parasitoids to examine the relationship between parasitoid species richness, functional group diversity and the provision of natural pest control services. Quantitative food webs were constructed for 10 organic and 10 conventional farms. Parasitoid species richness varied from 26 to 58 species and we found a significant positive relationship between parasitoid species richness and temporal stability in parasitism rates. Higher species richness was associated with lower variation in parasitism rate. A functional group analysis showed significantly greater parasitoid species complementarity on organic farms, with on average more species in each functional group. We simulated parasitoid removal to predict whether organic farms experienced greater robustness of parasitism in the face of local extinctions. This analysis showed no consistent differences between the organic and conventional farm pairs in terms of loss of pest control service. Finally, it was found that the different habitats that make up each farm do not contribute equally to parasitoid species diversity, and that hedgerows produced more parasitoid species, significantly more so on organic farms. PMID:21450736

  13. Larch sawfly, Pristiphora ericltsortii (Hymenoptera: Tenthredinidae) and its parasitoids from Alaska

    Science.gov (United States)

    James A. Richmond; Richard A. Werner; Arnold T. Drooz

    1995-01-01

    The larch sawfly and four parasitoids were reared in the laboratory from cocoons collected in Alaska for two consecutive years. Emergence of adult sawflies exceeded thirty percent each year. The number of parasitoids emerging was four times greater from the 1993 collection than from the subsequent year. Twelve Tritneptis klugii (Ratzeburg) emerged...

  14. Host feeding in insect parasitoids: why destructively feed upon a host that excretes an alternative?

    NARCIS (Netherlands)

    Burger, J.S.M.; Reijnen, T.M.; Van Lenteren, J.C.; Vet, L.E.M.

    2004-01-01

    Host feeding is the consumption of host tissue by the adult female parasitoid. We studied the function of destructive host feeding and its advantage over non-destructive feeding on host-derived honeydew in the whitefly parasitoid Encarsia formosa Gahan (Hymenoptera: Aphelinidae). We allowed

  15. 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 f...

  16. Host-age discrimination during host location by Cotesia glomerata, a larval parasitoid of Pieris brassicae.

    NARCIS (Netherlands)

    Mattiacci, L.; Dicke, M.

    1995-01-01

    Some parasitoids are restricted with respect to the host stage that they attack and even to a certain age within a stage. In this paper we investigate whether the parasitoid Cotesia glomerata can discriminate between old and young caterpillar instars of its host, Pieris brassicae, before contacting

  17. Parasitoids for biocontrol of coffee berry borer: past, present and future.

    Science.gov (United States)

    Detailed surveys for coffee berry borer parasitoids were initiated in October 2006 in two coffee growing areas of Kenya (Kisii and Embu). The most abundant parasitoid species are Prorops nasuta (Hymenoptera: Bethylidae) and Aphanogmus sp. (Hymenoptera: Ceraphronidae). Our preliminary findings indica...

  18. 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.

  19. Host-plant species conservatism and ecology of a parasitoid fig wasp genus (Chalcidoidea; Sycoryctinae; Arachonia.

    Directory of Open Access Journals (Sweden)

    Michael J McLeish

    Full Text Available Parasitoid diversity in terrestrial ecosystems is enormous. However, ecological processes underpinning their evolutionary diversification in association with other trophic groups are still unclear. Specialisation and interdependencies among chalcid wasps that reproduce on Ficus presents an opportunity to investigate the ecology of a multi-trophic system that includes parasitoids. Here we estimate the host-plant species specificity of a parasitoid fig wasp genus that attacks the galls of non-pollinating pteromalid and pollinating agaonid fig wasps. We discuss the interactions between parasitoids and the Ficus species present in a forest patch of Uganda in context with populations in Southern Africa. Haplotype networks are inferred to examine intraspecific mitochondrial DNA divergences and phylogenetic approaches used to infer putative species relationships. Taxonomic appraisal and putative species delimitation by molecular and morphological techniques are compared. Results demonstrate that a parasitoid fig wasp population is able to reproduce on at least four Ficus species present in a patch. This suggests that parasitoid fig wasps have relatively broad host-Ficus species ranges compared to fig wasps that oviposit internally. Parasitoid fig wasps did not recruit on all available host plants present in the forest census area and suggests an important ecological consequence in mitigating fitness trade-offs between pollinator and Ficus reproduction. The extent to which parasitoid fig wasps exert influence on the pollination mutualism must consider the fitness consequences imposed by the ability to interact with phenotypes of multiple Ficus and fig wasps species, but not equally across space and time.

  20. Parasitoid diversity reduces the variability in pest control services across time on farms.

    Science.gov (United States)

    Macfadyen, Sarina; Craze, Paul G; Polaszek, Andrew; van Achterberg, Kees; Memmott, Jane

    2011-11-22

    Recent declines in biodiversity have increased interest in the link between biodiversity and the provision and sustainability of ecosystem services across space and time. We mapped the complex network of interactions between herbivores and parasitoids to examine the relationship between parasitoid species richness, functional group diversity and the provision of natural pest control services. Quantitative food webs were constructed for 10 organic and 10 conventional farms. Parasitoid species richness varied from 26 to 58 species and we found a significant positive relationship between parasitoid species richness and temporal stability in parasitism rates. Higher species richness was associated with lower variation in parasitism rate. A functional group analysis showed significantly greater parasitoid species complementarity on organic farms, with on average more species in each functional group. We simulated parasitoid removal to predict whether organic farms experienced greater robustness of parasitism in the face of local extinctions. This analysis showed no consistent differences between the organic and conventional farm pairs in terms of loss of pest control service. Finally, it was found that the different habitats that make up each farm do not contribute equally to parasitoid species diversity, and that hedgerows produced more parasitoid species, significantly more so on organic farms.

  1. Small Island Visitor Attractions

    Directory of Open Access Journals (Sweden)

    Haven Allahar

    2015-03-01

    Full Text Available This article proposes a process framework for developing and managing visitor attractions (VA in small island developing states with Trinidad and Tobago, a two-island state in the Caribbean, as the case study. An extensive literature review was conducted, supported by field observations, individual depth interviews, and small and large focus group meetings. The process framework identified four sets of processes: national policy formulation and legislation; inventory, classification, evaluation, and ranking of VA; general operations management involving project management activities; and site specific activities of development, operations, and maintenance. The value of the framework lies in the fact that no similar framework applicable to small islands was covered in the literature and validation was obtained from a panel of experts and a cross section of tourism stakeholders in Tobago.

  2. Climate change and biological control: the consequences of increasing temperatures on host-parasitoid interactions.

    Science.gov (United States)

    Furlong, Michael J; Zalucki, Myron P

    2017-04-01

    The relative thermal requirements and tolerances of hymenopteran parasitoids and their hosts were investigated based on published data. The optimal temperature (Topt) for development of parasitoids was significantly lower than that for their hosts. Given the limited plasticity of insect responses to high temperatures and the proximity of Topt to critical thermal maxima, this suggests that host-parasitoid interactions could be negatively affected by increasing global temperatures. A modelling study of the interactions between the diamondback moth and its parasitoid Diadegma semiclausum in Australia indicated that predicted temperature increases will have a greater negative impact on the distribution of the parasitoid than on its host and that they could lead to its exclusion from some agricultural regions where it is currently important. Copyright © 2017 Elsevier Inc. All rights reserved.

  3. Phylogenetic signal detection from an ancient rapid radiation: Effects of noise reduction, long-branch attraction, and model selection in crown clade Apocynaceae.

    Science.gov (United States)

    Straub, Shannon C K; Moore, Michael J; Soltis, Pamela S; Soltis, Douglas E; Liston, Aaron; Livshultz, Tatyana

    2014-11-01

    Crown clade Apocynaceae comprise seven primary lineages of lianas, shrubs, and herbs with a diversity of pollen aggregation morphologies including monads, tetrads, and pollinia, making them an ideal group for investigating the evolution and function of pollen packaging. Traditional molecular systematic approaches utilizing small amounts of sequence data have failed to resolve relationships along the spine of the crown clade, a likely ancient rapid radiation. The previous best estimate of the phylogeny was a five-way polytomy, leaving ambiguous the homology of aggregated pollen in two major lineages, the Periplocoideae, which possess pollen tetrads, and the milkweeds (Secamonoideae plus Asclepiadoideae), which possess pollinia. To assess whether greatly increased character sampling would resolve these relationships, a plastome sequence data matrix was assembled for 13 taxa of Apocynaceae, including nine newly generated complete plastomes, one partial new plastome, and three previously reported plastomes, collectively representing all primary crown clade lineages and outgroups. The effects of phylogenetic noise, long-branch attraction, and model selection (linked versus unlinked branch lengths among data partitions) were evaluated in a hypothesis-testing framework based on Shimodaira-Hasegawa tests. Discrimination among alternative crown clade resolutions was affected by all three factors. Exclusion of the noisiest alignment positions and topologies influenced by long-branch attraction resulted in a trichotomy along the spine of the crown clade consisting of Rhabdadenia+the Asian clade, Baisseeae+milkweeds, and Periplocoideae+the New World clade. Parsimony reconstruction on all optimal topologies after noise exclusion unambiguously supports parallel evolution of aggregated pollen in Periplocoideae (tetrads) and milkweeds (pollinia). Our phylogenomic approach has greatly advanced the resolution of one of the most perplexing radiations in Apocynaceae, providing the

  4. Heterosexual men's ratings of sexual attractiveness of pubescent girls: Effects of labeling the target as under or over the age of sexual consent.

    Science.gov (United States)

    O'Donnell, Muireann; Lowe, Rob; Brotherton, Hannah; Davies, Hannah; Panou, Anna; Bennett, Paul

    2014-02-01

    The study aimed to identify implicit and explicit processes involved in reporting the sexual attractiveness of photographs of the same pubescent girls labeled as either under or within the age of sexual consent in the UK, women, and men. In two studies, 53 and 70 heterosexual men (M age 25.2 and 31.0 years) rated the sexual attractiveness of photographs in each category presented via computer [seeing target photographs of girls labeled as either under- (14-15 years) or within the age of consent (16-17 years)], using a 7-point response box. Ratings in Study 1 were in response to a question asking participants to rate how sexually attractive the person in each photograph was. In Study 2, participants rated how sexually attractive they personally found the target. Response times were also recorded. Several findings were replicated in both studies (although the strength of findings differed). Mean ratings of the sexual attractiveness of the underage girls were lower than those of overage girls and women. In addition, correlations revealed significantly longer responding times when "underage" girls (and men) were rated as more highly sexually attractive. No such relationship emerged with the same girls labeled within the age of consent or women. Overall, these data suggest that men find pubescent girls identified as being under the age of consent sexually attractive, but inhibit their willingness to report this; the greater the attraction, the greater the inhibition.

  5. 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)

    Albert E. Mayfield; James L. Hanula

    2012-01-01

    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...

  6. Host preference between symbiotic and aposymbiotic Aphis fabae, by the aphid parasitoid, Lysiphlebus ambiguus.

    Science.gov (United States)

    Cheng, Rui-Xia; Meng, Ling; Mills, Nickolas J; Li, Baoping

    2011-01-01

    Few empirical studies have directly explored the association between Buchnera aphidicola (Enterobacteriales: Enterobacteriaceae), the primary endosymbiont of aphids, and the life history strategies of aphid parasitoids. A series of paired-choice experiments were conducted to explore the preference of the parasitoid Lysiphlebus ambiguus Halliday (Hymenoptera: Aphididae) for symbiotic and aposymbiotic Aphis fabae Scopoli (Hemiptera: Aphididae) and the suitability of these hosts for parasitoid development. When given a choice between symbiotic and aposymbiotic aphids of the same instar, the parasitoid significantly preferred symbiotic over aposymbiotic aphids only during the later instars (L(4) and adult). The suitability of aposymbiotic aphids for parasitoid development was equal to that of symbiotic aphids in terms of survivorship and sex ratio, but was significantly lower than that of symbiotic aphids for L(4) and adult instars in development rate and/or female adult size. When given a choice between similar-sized symbiotic L(2) and aposymbiotic L(4) aphids, the parasitoid preferred the former. No significant differences in preference or host suitability were demonstrated when the parasitoid was given a choice between different instars of aposymbiotic aphids. While parasitoid lifetime fecundity increased with aphid instar at the time of oviposition, there was no significant influence of previous development from symbiotic versus aposymbiotic aphids. These results suggest that while L. ambiguus can discriminate between symbiotic and aposymbiotic A. fabae during later instars and when the aphids are of a similar size, the primary endosymbiont is not needed for successful parasitoid development; and its absence only compromises parasitoid growth reared from later instar aposymbiotic host.

  7. Is There an Own-Race Preference in Attractiveness?

    National Research Council Canada - National Science Library

    Burke, Darren; Nolan, Caroline; Hayward, William Gordon; Russell, Robert; Sulikowski, Danielle

    2013-01-01

    .... We tested whether there is an own-race preference in attractiveness judgments, and also examined the effect of familiarity by comparing the attractiveness ratings given by participants of different...

  8. 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.

  9. 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.

  10. Bacterial Communities Differ among Drosophila melanogaster Populations and Affect Host Resistance against Parasitoids

    Science.gov (United States)

    Dini-Andreote, Francisco; Falcao Salles, Joana

    2016-01-01

    In Drosophila, diet is considered a prominent factor shaping the associated bacterial community. However, the host population background (e.g. genotype, geographical origin and founder effects) is a factor that may also exert a significant influence and is often overlooked. To test for population background effects, we characterized the bacterial communities in larvae of six genetically differentiated and geographically distant D. melanogaster lines collected from natural populations across Europe. The diet for these six lines had been identical for ca. 50 generations, thus any differences in the composition of the microbiome originates from the host populations. We also investigated whether induced shifts in the microbiome—in this case by controlled antibiotic administration—alters the hosts’ resistance to parasitism. Our data revealed a clear signature of population background on the diversity and composition of D. melanogaster microbiome that differed across lines, even after hosts had been maintained at the same diet and laboratory conditions for over 4 years. In particular, the number of bacterial OTUs per line ranged from 8 to 39 OTUs. Each line harboured 2 to 28 unique OTUs, and OTUs that were highly abundant in some lines were entirely missing in others. Moreover, we found that the response to antibiotic treatment differed among the lines and significantly altered the host resistance to the parasitoid Asobara tabida in one of the six lines. Wolbachia, a widespread intracellular endosymbiont associated with parasitoid resistance, was lacking in this line, suggesting that other components of the Drosophila microbiome caused a change in host resistance. Collectively, our results revealed that lines that originate from different population backgrounds show significant differences in the established Drosophila microbiome, outpacing the long-term effect of diet. Perturbations on these naturally assembled microbiomes to some degree influenced the hosts

  11. Bacterial Communities Differ among Drosophila melanogaster Populations and Affect Host Resistance against Parasitoids.

    Science.gov (United States)

    Chaplinska, Mariia; Gerritsma, Sylvia; Dini-Andreote, Francisco; Falcao Salles, Joana; Wertheim, Bregje

    2016-01-01

    In Drosophila, diet is considered a prominent factor shaping the associated bacterial community. However, the host population background (e.g. genotype, geographical origin and founder effects) is a factor that may also exert a significant influence and is often overlooked. To test for population background effects, we characterized the bacterial communities in larvae of six genetically differentiated and geographically distant D. melanogaster lines collected from natural populations across Europe. The diet for these six lines had been identical for ca. 50 generations, thus any differences in the composition of the microbiome originates from the host populations. We also investigated whether induced shifts in the microbiome-in this case by controlled antibiotic administration-alters the hosts' resistance to parasitism. Our data revealed a clear signature of population background on the diversity and composition of D. melanogaster microbiome that differed across lines, even after hosts had been maintained at the same diet and laboratory conditions for over 4 years. In particular, the number of bacterial OTUs per line ranged from 8 to 39 OTUs. Each line harboured 2 to 28 unique OTUs, and OTUs that were highly abundant in some lines were entirely missing in others. Moreover, we found that the response to antibiotic treatment differed among the lines and significantly altered the host resistance to the parasitoid Asobara tabida in one of the six lines. Wolbachia, a widespread intracellular endosymbiont associated with parasitoid resistance, was lacking in this line, suggesting that other components of the Drosophila microbiome caused a change in host resistance. Collectively, our results revealed that lines that originate from different population backgrounds show significant differences in the established Drosophila microbiome, outpacing the long-term effect of diet. Perturbations on these naturally assembled microbiomes to some degree influenced the hosts' resistance

  12. Bacterial Communities Differ among Drosophila melanogaster Populations and Affect Host Resistance against Parasitoids.

    Directory of Open Access Journals (Sweden)

    Mariia Chaplinska

    Full Text Available In Drosophila, diet is considered a prominent factor shaping the associated bacterial community. However, the host population background (e.g. genotype, geographical origin and founder effects is a factor that may also exert a significant influence and is often overlooked. To test for population background effects, we characterized the bacterial communities in larvae of six genetically differentiated and geographically distant D. melanogaster lines collected from natural populations across Europe. The diet for these six lines had been identical for ca. 50 generations, thus any differences in the composition of the microbiome originates from the host populations. We also investigated whether induced shifts in the microbiome-in this case by controlled antibiotic administration-alters the hosts' resistance to parasitism. Our data revealed a clear signature of population background on the diversity and composition of D. melanogaster microbiome that differed across lines, even after hosts had been maintained at the same diet and laboratory conditions for over 4 years. In particular, the number of bacterial OTUs per line ranged from 8 to 39 OTUs. Each line harboured 2 to 28 unique OTUs, and OTUs that were highly abundant in some lines were entirely missing in others. Moreover, we found that the response to antibiotic treatment differed among the lines and significantly altered the host resistance to the parasitoid Asobara tabida in one of the six lines. Wolbachia, a widespread intracellular endosymbiont associated with parasitoid resistance, was lacking in this line, suggesting that other components of the Drosophila microbiome caused a change in host resistance. Collectively, our results revealed that lines that originate from different population backgrounds show significant differences in the established Drosophila microbiome, outpacing the long-term effect of diet. Perturbations on these naturally assembled microbiomes to some degree influenced

  13. Attraction of two lacewing species to volatiles produced by host plants and aphid prey

    Science.gov (United States)

    Zhu, J.; Obrycki, J. J.; Ochieng, Samuel A.; Baker, Thomas C.; Pickett, J. A.; Smiley, D.

    2005-06-01

    It is well documented that host-related odors enable many species of parasitoids and predatory insects to locate their prey and prey habitats. This study reports the first characterization of prey and prey host odor reception in two species of lacewings, Chrysoperla carnea (Say) and Chrysopa oculata L. 2-Phenylethanol, one of the volatiles emitted from their prey’s host plants (alfalfa and corn) evoked a significant EAG response from antennae of C. carnea. Traps baited with this compound attracted high numbers of adult C. carnea, which were predominantly females. One of the sex pheromone components (1R,4aS,7S,7aR)-nepetalactol of an aphid species, Acyrthosiphon pisum (Harris) attracted only C. oculata adults. Single sensillum recordings showed that the olfactory neurons of C. carnea responded to both 2-phenylethanol and aphid sex pheromone components, but those of C. oculata only responded to the latter.

  14. Aphid-encoded variability in susceptibility to a parasitoid.

    Science.gov (United States)

    Martinez, Adam J; Ritter, Shannon G; Doremus, Matthew R; Russell, Jacob A; Oliver, Kerry M

    2014-06-10

    Many animals exhibit variation in resistance to specific natural enemies. Such variation may be encoded in their genomes or derived from infection with protective symbionts. The pea aphid, Acyrthosiphon pisum, for example, exhibits tremendous variation in susceptibility to a common natural enemy, the parasitic wasp Aphidius ervi. Pea aphids are often infected with the heritable bacterial symbiont, Hamiltonella defensa, which confers partial to complete resistance against this parasitoid depending on bacterial strain and associated bacteriophages. That previous studies found that pea aphids without H. defensa (or other symbionts) were generally susceptible to parasitism, together with observations of a limited encapsulation response, suggested that pea aphids largely rely on infection with H. defensa for protection against parasitoids. However, the limited number of uninfected clones previously examined, and our recent report of two symbiont-free resistant clones, led us to explicitly examine aphid-encoded variability in resistance to parasitoids. After rigorous screening for known and unknown symbionts, and microsatellite genotyping to confirm clonal identity, we conducted parasitism assays using fifteen clonal pea aphid lines. We recovered significant variability in aphid-encoded resistance, with variation levels comparable to that contributed by H. defensa. Because resistance can be costly, we also measured aphid longevity and cumulative fecundity of the most and least resistant aphid lines under permissive conditions, but found no trade-offs between higher resistance and these fitness parameters. These results indicate that pea aphid resistance to A. ervi is more complex than previously appreciated, and that aphids employ multiple tactics to aid in their defense. While we did not detect a tradeoff, these may become apparent under stressful conditions or when resistant and susceptible aphids are in direct competition. Understanding sources and amounts of

  15. Relative Toxicity of Spirotetramat to Riptortus pedestris (Hemiptera: Alydidae) and its Egg Parasitoids.

    Science.gov (United States)

    Dangi, Naresh; Lim, Un Taek

    2017-10-01

    Spirotetramat, a lipid biosynthesis inhibitor, is effective against sucking insect pests but harmless to insect natural enemies. As spirotetramat can be registered for the management of sucking insect pests such as aphids and bugs in soybeans, we evaluated the insecticide against Riptortus pedestris (Fabricius) (Hemiptera: Alydidae), one of the most important soybean pests in Korea, as well as its effect on two of its important egg parasitoids, Ooencyrtus nezarae Ishii (Hymenoptera: Encyrtidae) and Gryon japonicum (Ashmead; Hymenoptera: Platygastridae). Oral toxicities of five concentrations of spirotetramat (1.00, 0.50, 0.25, 0.13, and 0.06 ml/liter) were tested by feeding these test solutions to insects for 24 h after 12 h of starvation. The lethal median concentration (LC50) for second instars of the bean bug was 0.3 ml/liter after 48 h while values for fourth instars and adults were 9.2 and 19.0 ml/liter, respectively. The median lethal time (LT50) for bean bugs when exposed to a concentration of 0.50 ml/liter was 1.2-1.5 times less than that of the control, while in G. japonicum and O. nezarae it was 1.1-1.2 times less than the control. These results show that spirotetramat is less toxic to the egg parasitoids of bean bug than to bean bug itself and would thus be useful in an integrated management program for this pest. © The Author 2017. Published by Oxford University Press on behalf of Entomological Society of America. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  16. Interaction Between Bt-Transgenic Cotton and the Whitefly’s Parasitoid, Encarsia Formosa (Hymenoptera: Aphelinidae

    Directory of Open Access Journals (Sweden)

    Azimi Solmaz

    2014-07-01

    Full Text Available Transgenic Bt cotton developed against lepidopteran pests may not be compatible with parasitoid of secondary pests such as Bemisia tabaci which attack many plants such as cotton. In this study, the effects of Bt cotton on the demographic parameters of Encarsia formosa, parasitoid of B. tabaci were assessed. The data were analysed using the age specific, two-sex life table parameters. The results indicated that pre-adult developmental time, the total preoviposition period (TPOP and the adult preoviposition period (APOP in the Bt cotton were significantly longer than in the non-Bt cotton. Also, fecundity and body size in both lines were significantly different. The fecundity was 23.64±0.73 and 43.75±0.89 eggs/females in the Bt and non-Bt cotton, respectively. All the population parameters were affected by the Bt cotton. The intrinsic rate of increase (r was 0.15 day-1 in the non-Bt cotton but it was 0.10 day-1 in the Bt cotton. The finite rate of increase (λ was 1.11 day-1 in the non-Bt cotton whilst it was 1.08 in the Bt cotton. The net reproductive rate (R0 in the non-Bt cotton was 36.75 but in the Bt cotton these parameters showed 19.62 offspring/individual. Also, the mean generation time (T in the non-Bt and Bt cotton was 22.69 and 27.79 days, respectively. The results illustrated, that although transgenic crops are effective tools for management of the target pests, they can adversely affect, either directly or indirectly, the natural enemies dependent on these plants.

  17. Extracellular superoxide dismutase in insects: characterization, function, and interspecific variation in parasitoid wasp venom.

    Science.gov (United States)

    Colinet, Dominique; Cazes, Dominique; Belghazi, Maya; Gatti, Jean-Luc; Poirié, Marylène

    2011-11-18

    Endoparasitoid wasps inject venom proteins with their eggs to protect them from the host immune response and ensure successful parasitism. Here we report identification of Cu,Zn superoxide dismutase (SOD) transcripts for both intracellular SOD1 and extracellular SOD3 in the venom apparatus of two Leptopilina species, parasitoids of Drosophila. Leptopilina SODs show sequence and structure similarity to human SODs, but phylogenetic analyses indicate that the extracellular SODs are more related to cytoplasmic vertebrate SODs than to extracellular SODs, a feature shared by predicted insect extracellular SODs. We demonstrate that L. boulardi SOD3 is indeed secreted and active as monomeric glycosylated forms in venom. Our results also evidence quantitative variation in SOD3 venom contents between closely related parasitoid species, as sod3 is 100-fold less expressed in Leptopilina heterotoma venom apparatus and no protein and SOD activity are detected in its venom. Leptopilina recombinant SOD3s as well as a mammalian SOD in vitro inhibit the Drosophila phenoloxidase activity in a dose-dependent manner, demonstrating that SODs may interfere with the Drosophila melanization process and, therefore, with production of cytotoxic compounds. Although the recombinant L. boulardi SOD3 quantity needed to observe this effect precludes a systemic effect of the wasp venom SOD3, it is still consistent with a local action at oviposition. This work provides the first demonstration that insect extracellular SODs are indeed secreted and active in an insect fluid and can be used as virulence factors to counteract the host immune response, a strategy largely used by bacterial and fungal pathogens but also protozoan parasites during infection.

  18. Parasitoid Hama Penggerek Batang dan Pucuk Tebu di Cinta Manis, Ogan Ilir Sumatera Selatan

    Directory of Open Access Journals (Sweden)

    Dewi Meidalima

    2014-03-01

    Full Text Available Serangan hama penggerek  tebu siap panen sebesar 11,25% di Cinta Manis tahun 2007. Lahan pengamatan 1 ha di bagi menjadi 5 petak secara diagonal, masing-masing seluas 200 m2, populasi tanaman sebanyak 1500 batang. Tujuan penelitian mengetahui keanekaragaman, spesies parasitoid dan potensi parasitasinya. Ditemukan 3 spesies parasitoid telur (Trichogramma chilonis; Telenomus dignoides; Tetrastichus schoenobii dan 3  spesies parasitoid larva (Rachonathus scirpophagae; Stenobracon nicevillei; Diatraeophaga striatalis.  Parasitisasi parasitoid telur penggerek pucuk di lahan dengan dan tanpa tumbuhan liar oleh Telenomus dignoides, Tetrastichus schoenobii, Trichogramma chilonis sebesar 6,96% dan 80,48%; 29,13% dan 15,22%; 0% dan 0,71%.   Parasitisasi parasitoid telur penggerek batang di lahan dengan dan tanpa tumbuhan liar oleh Tetrastichus schoenobii sebesar 48,88% dan 36,08%, Telenomus dignoides sebesar 29,35% dan 28,34%. Parasitisasi parasitoid larva penggerek pucuk di lahan dengan dan tanpa tumbuhan liar oleh Rachonothus scirpophagae sebesar 2,66% dan 1,59%, dan Stenobracon nicevillei sebesar  1,81% dan 0,99%.  Parasitisasi parasitoid larva penggerek batang (Diatraeophaga striatalis, di lahan dengan dan tanpa tumbuhan liar sebesar 32,23% dan 19,62%. Keanekaragaman spesies parasitoid telur (H’=0,627dan larva penggerek pucuk (H’=0,686 tertinggi pada lahan dengan tumbuhan liar. Keanekaragaman spesies parasitoid telur penggerek batang tertinggi pada lahan tanpa tumbuhan liar adalah H’=0,686. During 2007 in Cinta Manis area, the attack of borers on readily harvested sugarcane reached 11.25%. A 1-ha observation field was divided diagonally into 5 plots, each with an area of 200 m2, and populated with 1,500 plants. The aims of this study were to know the diversity of parasitoids species and their parasitic potentials. As many as 3 species of parasitoid eggs (Trichogramma chilonis; Telenomus dignoides; Tetrastichus schoenobii and 3 species of

  19. 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

  20. Effects of internal tidal dissipation and self-attraction and loading on semidiurnal tides in the Bohai Sea, Yellow Sea and East China Sea: a numerical study

    Science.gov (United States)

    Teng, Fei; Fang, Guohong; Xu, Xiaoqing

    2017-09-01

    A parameterized internal tide dissipation term and self-attraction and loading (SAL) tide term are introduced in a barotropic numerical model to investigate the dynamics of semidiurnal tidal constituents M 2 and S 2 in the Bohai Sea, Yellow Sea and East China Sea (BYECS). The optimal parameters for bottom friction and internal dissipation are obtained through a series of numerical computations. Numerical simulation shows that the tide-generating force contributes 1.2% of M 2 power for the entire BYECS and up to 2.8% for the East China Sea deep basin. SAL tide contributes 4.4% of M 2 power for the BYECS and up to 9.3% for the East China Sea deep basin. Bottom friction plays a major role in dissipating tidal energy in the shelf regions, and the internal tide effect is important in the deep water regions. Numerical experiments show that artificial removal of tide-generating force in the BYECS can cause a significant difference (as much as 30 cm) in model output. Artificial removal of SAL tide in the BYECS can cause even greater difference, up to 40 cm. This indicates that SAL tide should be taken into account in numerical simulations, especially if the tide-generating force is considered.

  1. A review of hymenopterous parasitoid guilds attacking Anastrepha spp. and Ceratitis capitata (Diptera: Tephritidae) in Argentina

    Energy Technology Data Exchange (ETDEWEB)

    Ovruski, Sergio M.; Orono, Luis E.; Nunez-Campero, Segundo; Schliserman, Pablo; Albornoz-Medina, Patricia; Bezdjian, Laura P.; Nieuwenhove, Guido A. Van; Martin, Cristina B. [Consejo Nacional de Investigaciones Cientificas y Tecnicas (CONICET), Tucuman (Argentina). Planta Piloto de Procesos Industriales Microbiologicos y Biotecnologia. Div. Control Biologico de Plagas

    2006-07-01

    This study provides detailed information on the diversity, abundance, guilds, host plant and host fly ranges, distribution, and taxonomic status of hymenopterous parasitoid species associated with Ceratitis capitata (Wiedemann) and Anastrepha spp. (A. fraterculus (Wiedemann) and A. schultzi Blanchard) in Argentina. Moreover, the article also argues future needs regarding the use of some parasitoid species as an alternative tool in fruit fly management programs of the National Fruit Fly Control and Eradication Program (PROCEM-Argentina). Data used for this work were obtained from numerous old and recent published articles on fruit fly parasitoids in Argentina. (author)

  2. 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

    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...

  3. Creating beauty: creativity compensates for low physical attractiveness when individuals assess the attractiveness of social and romantic partners.

    Science.gov (United States)

    Watkins, Christopher D

    2017-04-01

    Although creativity is attractive in a potential mate, it is unclear (i) whether the effects of creativity on attractiveness generalize to other social contexts and (ii) whether creativity has equivalent effects on men's and women's attractiveness. As social knowledge of creativity may either enhance or 'offset' the appeal of social partners who differ in physical attractiveness, three repeated measures experiments were conducted to directly address these issues. Here, participants rated a series of face-text pairs for attractiveness on trials that differed in one of four combinations of facial attractiveness (attractive and less attractive) and creativity (creative and less creative), rating story-tellers in two experiments (short interpretations of an identical painting) and creative ideas in a further experiment (alternative uses for an everyday object). Regardless of the sex of the judge, creativity and facial attractiveness had independent effects on men's overall attractiveness (initial experiment) and, in further experiments, more substantial effects on the attractiveness of men with less attractive faces than men with attractive faces (when using a different measure of creativity) and specific effects on the attractiveness of individuals with less attractive faces (when using different face stimuli). Collectively, across three experiments, these findings suggest that creativity may compensate for putative cues to lower biological 'quality' and that the benefits of creativity to social groups more generally enhance attraction to creative men (in two experiments) and creative men and women (one experiment). More broadly, the data suggest that species can integrate knowledge of cognitive intelligence with visual cues to biological 'quality' to facilitate mate and/or ally choice.

  4. Creating beauty: creativity compensates for low physical attractiveness when individuals assess the attractiveness of social and romantic partners

    Science.gov (United States)

    2017-01-01

    Although creativity is attractive in a potential mate, it is unclear (i) whether the effects of creativity on attractiveness generalize to other social contexts and (ii) whether creativity has equivalent effects on men's and women's attractiveness. As social knowledge of creativity may either enhance or ‘offset’ the appeal of social partners who differ in physical attractiveness, three repeated measures experiments were conducted to directly address these issues. Here, participants rated a series of face–text pairs for attractiveness on trials that differed in one of four combinations of facial attractiveness (attractive and less attractive) and creativity (creative and less creative), rating story-tellers in two experiments (short interpretations of an identical painting) and creative ideas in a further experiment (alternative uses for an everyday object). Regardless of the sex of the judge, creativity and facial attractiveness had independent effects on men's overall attractiveness (initial experiment) and, in further experiments, more substantial effects on the attractiveness of men with less attractive faces than men with attractive faces (when using a different measure of creativity) and specific effects on the attractiveness of individuals with less attractive faces (when using different face stimuli). Collectively, across three experiments, these findings suggest that creativity may compensate for putative cues to lower biological ‘quality’ and that the benefits of creativity to social groups more generally enhance attraction to creative men (in two experiments) and creative men and women (one experiment). More broadly, the data suggest that species can integrate knowledge of cognitive intelligence with visual cues to biological ‘quality’ to facilitate mate and/or ally choice. PMID:28484614

  5. How do landscape composition and configuration, organic farming and fallow strips affect the diversity of bees, wasps and their parasitoids?

    Science.gov (United States)

    Holzschuh, Andrea; Steffan-Dewenter, Ingolf; Tscharntke, Teja

    2010-03-01

    1. Habitat destruction and increasing land use intensity result in habitat loss, fragmentation and degradation, and subsequently in the loss of species diversity. The fact that these factors are often highly confounded makes disentangling their effects extremely difficult, if not impossible, and their relative impact on species loss is mostly speculative. 2. In a two-year study, we analysed the relative importance of changed landscape composition (increased areas of cropped habitats), reduced habitat connectivity and reduced habitat quality on nest colonization of cavity-nesting bees, wasps and their parasitoids. We selected 23 pairs of conventional and organic wheat fields in the centre of landscape circles (500 m radius) differing in edge densities (landscape configuration) and % non-crop habitats (landscape composition). Standardized trap nests were established in the field centres and in neighbouring permanent fallow strips (making a total of 92 nesting sites). 3. Factors at all three scales affected nest colonization. While bees were enhanced by high proportions of non-crop habitat in the landscape, wasps profited from high edge densities, supporting our hypothesis that wasps are enhanced by connecting corridors. Colonization of herbivore-predating wasps was lower in field centres than in fallow strips for conventional sites, but not for organic sites, indicating a fallow-like connectivity value of organic fields. The relative importance of habitat type and farming system varied among functional groups suggesting that their perception of crop-non-crop boundaries or the availability of their food resources differed. 4. Local and landscape effects on parasitoids were mainly mediated by their hosts. Parasitism rates were marginally affected by local factors. A specialist parasitoid was more sensitive to high land use intensity than its host, whereas generalist parasitoids were less sensitive. 5. We conclude that the conversion of cropland into non-crop habitat

  6. Survival and development of a stored-product pest, Sitophilus zeamais (Coleoptera: Curculionidae), and its natural enemy, the parasitoid Lariophagus distinguendus (Hymenoptera. Pteromalidae), on transgenic Bt maize

    DEFF Research Database (Denmark)

    Hansen, Lise S.; Lövei, Gabor L; Székács, András

    2013-01-01

    Background The effect of transgenic maize (Zea mays L.) containing a lepidopteran-specific Bt toxin on a stored-product pest, Sitophilus zeamais Motschulsky, and its parasitoid, Lariophagus distinguendus Förster, was examined in the laboratory to test the impact of transgenic maize on stored...

  7. Cultured skin microbiota attracts malaria mosquitoes.

    Science.gov (United States)

    Verhulst, Niels O; Beijleveld, Hans; Knols, Bart Gj; Takken, Willem; Schraa, Gosse; Bouwmeester, Harro J; Smallegange, Renate C

    2009-12-17

    Host-seeking of the African malaria mosquito, Anopheles gambiae sensu stricto, is guided by human odours. The precise nature of the odours, and the composition of attractive blends of volatiles, remains largely unknown. Skin microbiota plays an important role in the production of human body odours. It is hypothesized that host attractiveness and selection of An. gambiae is affected by the species composition, density, and metabolic activity of the skin microbiota. A study is presented in which the production and constituency of volatile organic compounds (VOCs) by human skin microbiota is examined and the behavioural responses of An. gambiae to VOCs from skin microbiota are investigated. Blood agar plates incubated with skin microbiota from human feet or with a reference strain of Staphylococcus epidermidis were tested for their attractiveness to An. gambiae in olfactometer bioassays and indoor trapping experiments. Entrained air collected from blood agar plates incubated with natural skin microbiota or with S. epidermidis were analysed using GC-MS. A synthetic blend of the compounds identified was tested for its attractiveness to An. gambiae. Behavioural data were analysed by a chi(2)-test and GLM. GC-MS results were analysed by fitting an exponential regression line to test the effect of the concentration of bacteria. More An. gambiae were caught with blood agar plates incubated with skin bacteria than with sterile blood agar plates, with a significant effect of incubation time and dilution of the skin microbiota. When bacteria from the feet of four other volunteers were tested, similar effects were found. Fourteen putative attractants were found in the headspace of the skin bacteria. A synthetic blend of 10 of these was attractive to An. gambiae. The discovery that volatiles produced by human skin microorganisms in vitro mediate An. gambiae host-seeking behaviour creates new opportunities for the development of odour-baited trapping systems. Additionally

  8. DNA Attraction in Monovalent and Divalent Electrolytes

    Science.gov (United States)

    Luan, Binquan; Aksimentiev, Aleksei

    2010-01-01

    The dependence of the effective force on the distance between two DNA molecules was directly computed from a set of extensive all-atom molecular dynamics simulations. The simulations revealed that in a monovalent electrolyte the effective force is repulsive at short and long distances, but can be attractive in the intermediate range. This attractive force is, however, too weak (~5pN per turn of a DNA helix) to induce DNA condensation in the presence of thermal fluctuations. In divalent electrolytes, DNA molecules were observed to form a bound state, where Mg2+ ions bridged minor groves of DNA. The effective force in divalent electrolytes was predominantly attractive, reaching a maximum of 42pN per one turn of a DNA helix. PMID:18975864

  9. Koinophilia and Human Facial Attractiveness

    Indian Academy of Sciences (India)

    Home; Journals; Resonance – Journal of Science Education; Volume 20; Issue 4. Koinophilia and Human Facial Attractiveness. Aishwawriya Iyengar Rutvij Kulkarni T N C Vidya. General Article Volume 20 Issue 4 April 2015 pp 311-319 ... Keywords. Koinophilia; attractiveness; averaged faces; recognition; mate choice.

  10. AIM: Attracting Women into Sciences.

    Science.gov (United States)

    Hartman, Icial S.

    1995-01-01

    Addresses how to attract more college women into the sciences. Attracting Women into Sciences (AIM) is a comprehensive approach that begins with advising, advertising, and ambiguity. The advising process includes dispelling stereotypes and reviewing the options open to a female basic science major. Interaction, involvement and instruction, finding…

  11. The Measurement of Interpersonal Attraction.

    Science.gov (United States)

    McCroskey, James C.; McCain, Thomas A.

    This paper reports a factor analytic investigation of the interpersonal attraction construct. Two hundred-fifteen subjects completed 30 Likert-type, 7-step scales concerning an acquaintance. Factor analysis indicated three dimensions of the interpersonal attraction construct which were labeled "task,""social," and "physical." Obtained internal…

  12. Residual toxicity of insecticides used in Tunisian citrus orchards on the imported parasitoid Diachasmimorpha longicaudata (Hymenoptera: Braconidae: Implications for IPM program of Ceratitis capitata (Diptera: Tephritidae

    Directory of Open Access Journals (Sweden)

    Ahlem Harbi

    2017-11-01

    Full Text Available Citrus agro-industry is globally harshened mainly by Ceratitis capitata (Wiedemann, the most worldwide destructive tephritid fruit fly species. Citrus agro-industry is one of the pillars of Tunisia economy, and by hence, harshened by this species. Tunisia has established an Integrated Pest Management (IPM programme against citrus pests, including C. capitata, that rely on the structured use of pesticides, on the application several trapping protocols, along with pilot-scale sterile insect technique program and, since 2013, with pilot-scale releases of the braconid parasitoid Diachasmimorpha longicaudata Ashmed (Hymenoptera: Braconidae. Insecticide side-effects on parasitoids and other natural enemies are being requested for a successful implementation of biological control within any IPM programme. However, these data are almost scarce for the braconid species D. longicaudata. To this end, we have determined the side-effects of malathion, methidathion, acetamiprid, azadiractin, abamectin, deltametrin+thiacloprid and spinosad, as the most popular insecticides used in Tunisia either as fresh residues or at several aged time points, on the parasitoid D. longicaudata according the IOBC pesticide harm-classification. IOBC classification evolution of residues over time had allowed determining the best combination of pesticide applications in a structured fashion with the viable releases of D. longicaudata for the control of C. capitata in Tunisian citrus agro-ecosystems.

  13. Populations of predators and parasitoids of Bemisia tabaci (Hemiptera: Aleyrodidae) after the application of eight biorational insecticides in vegetable crops.

    Science.gov (United States)

    Simmons, Alvin M; Shaaban, Abd-Rabou

    2011-08-01

    The sweetpotato whitefly, Bemisia tabaci (Gennadius) (Hemiptera: Aleyrodidae), is an important pest of vegetables and many other crops worldwide. Eight biorational insecticides (based on oil, plant derivatives, insect growth regulator and fungus) were evaluated in the field for their influence on populations of six natural enemies of B. tabaci. Natural populations of two predators [Chrysoperla carnea Stephen (Neuroptera: Chrysopidae) and Orius spp. (Hemiptera: Anthocoridae)] and two genera of parasitoids [Encarsia spp. and Eretmocerus spp. (Hymenoptera: Aphelinidae)] were evaluated in eggplant (Solanum melongena L.). Also, augmented field populations of three predators [C. carnea, Coccinella undecimpunctata L. (Coleoptera: Coccinellidae) and Macrolophus caliginosus (Wagner) (Hemiptera: Miridae)] were evaluated in cabbage (Brassica oleracea var. capitata L.), cucumber (Cucumis sativus L.) and squash (Cucurbita pepo L.). Regardless of natural enemy or crop, jojoba oil, Biovar and Neemix had the least effect on abundance of the natural enemies in comparison with the other insecticides during a 14 day evaluation period. Conversely, Admiral, KZ oil, Mesrona oil, Mesrona oil + sulfur and natural oil had a high detrimental effect on abundance of the natural enemies. These results demonstrate the differential effects of biorational insecticides for whitefly control on predators and parasitoids in the field. This article is a US Government work and is in the public domain in the USA. Published 2011 by John Wiley & Sons, Ltd.

  14. Species composition and richness of aphid parasitoid wasps in cotton fields in northern China

    National Research Council Canada - National Science Library

    Fan Yang; Yue-Kun Wu; Lei Xu; Qian Wang; Zhi-Wen Yao; Vladimir Žikić; Željko Tomanović; Mar Ferrer-Suay; Jesús Selfa; Juli Pujade-Villar; Yan-Hui Lu; Yu-Yuan Guo

    2017-01-01

    .... In this study, we combine sampling over a broad geographical area with intensive field trials over the course of three cropping seasons to describe parasitoid-hyperparasitoid communities in cotton crops...

  15. Parasitoids attacking emerald ash borers in western Pennsylvania and their potential use in biological control

    Science.gov (United States)

    J.J. Duan; R.W. Fuester; J. Wildonger; P.B. Taylor; S. Barth; S-E. Spichiger

    2009-01-01

    Current biological control programs against the emerald ash borer (EAB, Agrilus planipennis Fairmaire) have primarily focused on the introduction and releases of exotic parasitoids from China, home of the pest origin....

  16. Evaluation of imported parasitoid fitness for biocontrol of olive fruit fly in California olives

    Science.gov (United States)

    A parasitoid, Psyttalia humilis (Silvestri), was reared on irradiated Mediterranean fruit fly (Medfly), Ceratitis capitata (Weidemann), at the USDA, APHIS, PPQ, Moscamed biological control laboratory in San Miguel Petapa, Guatemala, and imported into California for biological control of olive fruit ...

  17. The evolution of diapause in a coupled host-parasitoid system.

    Science.gov (United States)

    Ringel, M S; Rees, M; Godfray, H C

    1998-09-21

    Diapause of part of a population during a breeding opportunity is widespread among insects. We explore the evolution of such diapause in a coupled host-parasitoid system, using a discrete-generation population dynamic model that incorporates diapause. We show that diapause in the host tends to be a stabilizing factor while diapause in the parasitoid does not affect the stability boundaries. We then allow the frequency of diapause in the host and parasitoid to evolve, and find the joint population and evolutionary dynamic equilibrium by numerical methods. At the equilibrium, population dynamics exhibit cycles and host diapause always occurs. Parasitoid diapause often occurs, though this depends on exact parameter values. Thus, intrinsically generated fluctuations in fitness (due to cyclical population dynamics) lead to the evolution of diapause as a bet-hedging mechanism. Copyright 1998 Academic Press Limited

  18. Sugar in Moderation: Variable Sugar Diets Affect Short-Term Parasitoid Behavior

    Science.gov (United States)

    The biological control potential of parasitic wasps in the field is expected to increase with provisioning of sugar sources, which increase longevity and replenish carbohydrate reserves. Apanteles aristoteliae Viereck is an important parasitoid of Argyrotaenia franciscana (Walsingham), the orange to...

  19. Are aphid parasitoids locally adapted to the prevalence of defensive symbionts in their hosts?

    Science.gov (United States)

    Vorburger, Christoph; Rouchet, Romain

    2016-12-12

    Insect parasitoids are under strong selection to overcome their hosts' defences. In aphids, resistance to parasitoids is largely determined by the presence or absence of protective endosymbionts such as Hamiltonella defensa. Hence, parasitoids may become locally adapted to the prevalence of this endosymbiont in their host populations. To address this, we collected isofemale lines of the aphid parasitoid Lysiphlebus fabarum from 17 sites in Switzerland and France, at which we also estimated the frequency of infection with H. defensa as well as other bacterial endosymbionts in five important aphid host species. The parasitoids' ability to overcome H. defensa-mediated resistance was then quantified by estimating their parasitism success on a single aphid clone (Aphis fabae fabae) that was either uninfected or experimentally infected with one of three different isolates of H. defensa. The five aphid species (Aphis fabae fabae, A. f. cirsiiacanthoides, A. hederae, A. ruborum, A. urticata) differed strongly in the relative frequencies of infection with different bacterial endosymbionts, but there was also geographic variation in symbiont prevalence. Specifically, the frequency of infection with H. defensa ranged from 22 to 47 % when averaged across species. Parasitoids from sites with a high prevalence of H. defensa tended to be more infective on aphids possessing H. defensa, but this relationship was not significant, thus providing no conclusive evidence that L. fabarum is locally adapted to the occurrence of H. defensa. On the other hand, we observed a strong interaction between parasitoid line and H. defensa isolate on parasitism success, indicative of a high specificity of symbiont-conferred resistance. This study is the first, to our knowledge, to test for local adaptation of parasitoids to the frequency of defensive symbionts in their hosts. While it yielded useful information on the occurrence of facultative endosymbionts in several important host species of L

  20. Antagonistic Interactions between the African Weaver Ant Oecophylla longinoda and the Parasitoid Anagyrus pseudococci Potentially Limits Suppression of the Invasive Mealybug Rastrococcus iceryoides.

    Science.gov (United States)

    Tanga, Chrysantus M; Ekesi, Sunday; Govender, Prem; Nderitu, Peterson W; Mohamed, Samira A

    2015-12-23

    The ant Oecophylla longinoda Latreille forms a trophobiotic relationship with the invasive mealybug Rastrococus iceryoides Green and promotes the latter's infestations to unacceptable levels in the presence of their natural enemies. In this regard, the antagonistic interactions between the ant and the parasitoid Anagyrus pseudococci Girault were assessed under laboratory conditions. The percentage of parasitism of R. iceryoides by A. pseudococci was significantly higher on "ant-excluded" treatments (86.6% ± 1.27%) compared to "ant-tended" treatments (51.4% ± 4.13%). The low female-biased sex-ratio observed in the "ant-tended" treatment can be attributed to ants' interference during the oviposition phase, which disrupted parasitoids' ability to fertilize eggs. The mean foraging time, host handling time and number of successful oviposition in "ant-excluded" treatment were significantly higher compared to "ant-tended" treatments. When ant workers were allowed access to sterilized sand grains, mummified and unmummified R. iceryoides, they selectively removed the mummified mealybugs, indicating that they recognized the mummies as potential foods (1.2 ± 0.46 to 7.8 ± 1.17 mummies at 10 min intervals for 2 h). Percentage emergence from mummified R. iceryoides removed by the ants was significantly lower compared to emergence from mummies not exposed to ants. Although, host seeking parasitoids frequently evaded attacks, some were killed by the foraging ant workers (2.0 ± 0.38 to 6.0 ± 0.88 at 10 min intervals for 2 h). These results suggest for the first time that the presence of O. longinoda has a detrimental effect on the abundance, reproductive success and possibly oviposition strategy of female parasitoids, which might be a delimiting factor in field conditions if both natural enemies are to be recommended for use within the same agro-ecosystem.