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Sample records for attract parasitoids effects

  1. Effects of flower attractiveness and nectar availability in field margins on biological control by parasitoids

    NARCIS (Netherlands)

    Bianchi, F.J.J.A.; Wackers, F.L.

    2008-01-01

    Flowering plants have been shown to differ with regard to their attractiveness to parasitoids and nectar accessibility. These floral traits are likely to affect the foraging performance of parasitoids in agricultural landscapes. Using a spatially explicit simulation model we explore how the attracti

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

    Directory of Open Access Journals (Sweden)

    Xavier eMartini

    2014-05-01

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

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

    Directory of Open Access Journals (Sweden)

    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.

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

    NARCIS (Netherlands)

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

    2005-01-01

    Differences in allelochemistry of plants may influence their ability to attract parasitoids.We studied responses of Diadegma semiclausum (Hellén), a parasitoid of the diamondback moth (Plutella xylostella L.), to inter- and intraspecific variation in odor blends of crucifers and a non-crucifer speci

  5. 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: Ichneumonid

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

    Science.gov (United States)

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

    2016-03-01

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

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

    OpenAIRE

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

    2005-01-01

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

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

    International Nuclear Information System (INIS)

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

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

    Science.gov (United States)

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

    2005-03-01

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

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

    Directory of Open Access Journals (Sweden)

    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

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

    Science.gov (United States)

    Wilson, J K; Woods, H A

    2015-12-01

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

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

    Institute of Scientific and Technical Information of China (English)

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

    2008-01-01

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

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

    Science.gov (United States)

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

    2016-09-01

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

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

    Science.gov (United States)

    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. PMID:24959997

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

    Directory of Open Access Journals (Sweden)

    Turlings Ted CJ

    2010-11-01

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

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

    Science.gov (United States)

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

    2015-08-01

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

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

    Science.gov (United States)

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

    2013-08-01

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

  18. Plant effects on parasitoid foraging: differences between two tritrophic systems.

    NARCIS (Netherlands)

    Takabayashi, J.; Sato, Y.; Horikoshi, M.; Yamaoka, R.; Yano, S.; Ohsaki, N.; Dicke, M.

    1998-01-01

    Plants can affect the effectiveness of carnivorous insects in various ways. An important aspect is that herbivory results in the emission of plant volatiles that are used by carnivores to locate their herbivorous victims. Here we show that such plant volatiles may affect parasitoids differently in t

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

    Science.gov (United States)

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

    2016-01-01

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

  20. Effects of student physical attractiveness

    Directory of Open Access Journals (Sweden)

    Krnjajić Stevan B.

    2005-01-01

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

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

    NARCIS (Netherlands)

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

    2002-01-01

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

  2. 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...

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

    Science.gov (United States)

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

    2014-01-01

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

  4. Effects of selected insecticides on adults of two parasitoid species of Liriomyza trifolii: Ganaspidium nigrimanus (Figitidae) and Neochrysocharis formosa (Eulophidae)

    Institute of Scientific and Technical Information of China (English)

    Ricardo Hernández; Kun Guo; Marvin Harris; Tong-Xian Liu

    2011-01-01

    Liriomyza trifolii is an important pest of vegetables and ornamental crops around the world. This pest is attacked by many parasitoid species. The principal management tactic used against L. trifolii is insecticide application. Insecticides vary in their effects on parasitoid species and insecticides that have less harmful effects should be preferred for the control of this pest. In this study, novaluron, abamectin, λ-cyhalothrin and spinetoram were investigated for their lethal effects on adults of Neochrysocharisformosa and Ganaspidium nigrimanus, two important parasitoids of L. trifolii. Three different bioassays were used on adult parasitoids: direct insecticide application, insecticide intake and insecticide residue. Adult parasitoid response to novaluron exhibited the least lethal effects among the bioassays and insecticides tested. Abamectin had significant mortality to both parasitoid species in the direct application and insecticide intake bioassays and mortality were high for G. nigrimanus in the residue bioassay. Spinetoram was the most harmful insecticide to the adult parasitoids in all three bioassays. λ-cyhalothrin effects varied between the two parasitoids. In the direct application, it was harmful to G. nigrimanus and had no effect on N. formosa. In the insecticide intake bioassay λ-cyhalothrin had no effect in survival of either species, and in the residue bioassay it reduced parasitoid survival of both species.Potential tolerance of N. formosa to λ-cyhalothrin is discussed.

  5. Glassy-winged sharpshooter oviposition effects on photinia volatile chemistry with implications on egg parasitoid effectiveness

    Science.gov (United States)

    An effective way to limit incidence of Pierce’s disease of grapevine is to reduce populations of glassy-winged sharpshooter (GWSS), Homalodisca vitripennis (Germar) (Hemiptera: Cicadellidae), which transmit the causal bacterium, Xylella fastidiosa. One strategy is to utilize egg parasitoids such as ...

  6. Lethal and Sublethal Effects of Insecticides on the Egg Parasitoid Telenomus podisi (Hymenoptera: Platygastridae).

    Science.gov (United States)

    Turchen, L M; Golin, V; Butnariu, A R; Guedes, R N C; Pereira, M J B

    2016-02-01

    Insecticide use remains controversial, and subjected to increasing environmental and health concerns, even when recent insecticide groups are considered. Neonicotinoids and even bioinsecticides are in the forefront of discussions regarding their nontarget safety. The ubiquitous focus on the lethal effects of insecticides on nontarget species has been expanding to sublethal effects, as sublethal exposure extends for a longer time and affects a broader range of (nontarget) species. Here we explored the lethal and sublethal effects of a lambda-cyhalothrin + thiamethoxan mixture, the neonicotinoid imidacloprid, and the bioinsecticide azadirachtin on the egg parasitoid Telenomus podisi Ashmead, an important parasitoid of stink bug Euschistus heros (F.), a key soybean pest in neotropical America. Contact with dry insecticide residue on glass surface and (parasitized and healthy) host egg immersion exposure bioassays were performed, assessing their acute lethal effects, and their potential sublethal impairment of parasitism, adult emergence, and fertility of the egg parasitoid. Both imidacloprid and the insecticide mixture exhibited high acute lethal activity toward the parasitoid under contact with dry insecticide residue. These insecticides compromised parasitism and wasp emergence when exposure took place before parasitism. In contrast, azadirachtin did not affect adult survival. However, this bioinsecticide compromised parasitism and progeny production, impairing the female parasitoid reproductive potential. Our results indicate strong negative effects of imidacloprid, and specially of the mixture lambda-cyhalthrin + thiamethoxan. However, even azadirachtin, which exhibited low acute lethality, exhibited significant negative sublethal effects on parasitism and population growth of egg parasitoid, cautioning against their use and the need of semifield and field assessments to confirm such an impact. PMID:26352754

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

    Science.gov (United States)

    Charles, Jennifer J; Paine, Timothy D

    2016-01-01

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

  8. 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.

    Science.gov (United States)

    Dannon, Elie A; Tamò, Manuele; Van Huis, Arnold; Dicke, Marcel

    2010-10-01

    The parasitoid wasp Apanteles taragamae is a promising candidate for the biological control of the legume pod borer Maruca vitrata, which recently has been introduced into Benin. The effects of volatiles from cowpea and peabush flowers and Maruca vitrata larvae on host selection behavior of the parasitoid Apanteles taragamae were investigated under laboratory conditions by using a Y-tube olfactometer. Naïve and oviposition-experienced female wasps were given a choice between several odor sources that included (1) uninfested, (2) Maruca vitrata-infested, and (3) mechanically damaged cowpea flowers, as well as (4) stem portions of peabush plants carrying leaves and flowers, (5) healthy M. vitrata larvae, and moribund (6), and live (7) virus-infected M. vitrata larvae. Responses of naïve and oviposition-experienced female wasps did not differ for any of the odor source combinations. Wasps were significantly attracted to floral volatiles produced by cowpea flowers that had been infested with M. vitrata larvae and from which the larvae had been removed. Apanteles taragamae females also were attracted to Maruca vitrata-infested flowers after removal of both the larvae and their feces. Female wasps discriminated between volatiles from previously infested flowers and mechanically damaged flowers. Uninfested cowpea flowers attracted only oviposition-experienced wasps that had received a rewarding experience (i.e. the parasitization of two M. vitrata larvae feeding on cowpea flowers) before the olfactometer test. Wasps also were attracted to uninfested leaves and flowers of peabush. Moreover, they were also attracted to healthy and live virus-infected M. vitrata larvae, but not when the latter were moribund. Our data show that, similarly to what has been extensively been reported for foliar volatiles, flowers of plants also emit parasitoid-attracting volatiles in response to being infested with an herbivore.

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

    Science.gov (United States)

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

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

    Science.gov (United States)

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

    2016-04-01

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

  11. 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

  12. Effects of local vegetation and plantation age for the parasitoid Asecodes mento-a biocontrol agent in organic strawberry fields

    Institute of Scientific and Technical Information of China (English)

    Johan A.Stenberg

    2012-01-01

    The parasitoid Asecodes mento (Walker,1839) (Hymenoptera:Eulophidae)is the most important biocontrol agent of the strawberry leaf beetle Galerucella tenella (L.) (Coleoptera:Chrysomelidae) in northern Europe.Here,I investigated whether natural parasitism in organic strawberry plantations was affected by the presence of the alternative host plant meadowsweet (Filipendula ulmaria),and whether parasitism rates differed between plantations of different ages (6 to 79 years).I also investigated whether parasitoid brood size,body size and sex ratio differed between the two host plants in the field.Parasitism was very low (0%) in newly established plantations and increased to a plateau (~40%) in fields where strawberries had been grown for approximately 20 years or longer.Such an extended colonization process is unacceptable for commercial growers.It would thus be desirable to find a method to catalyze parasitoid population buildup in young plantations.Parasitoid brood sizes were larger in beetles collected from meadowsweet,while body size and sex ratio did not differ between parasitoids collected from the two plants.These findings suggest that meadowsweet can export parasitoids to neighboring strawberry fields.Although this is a possibility,I did not find any significant differences in parasitism rates between isolated strawberry fields and fields adjacent to meadowsweet stands,indicating that effects of local vegetation are small on parasitism rates.Releasing parasitoids in newly established strawberry plantations may be a better strategy for quickly obtaining high parasitism than intercropping with meadowsweet.

  13. 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 paras

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

    Science.gov (United States)

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

    2015-04-01

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

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

    Science.gov (United States)

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

    2015-04-01

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

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

    Science.gov (United States)

    Charles, Jennifer J.; Paine, Timothy D.

    2016-01-01

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

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

    Directory of Open Access Journals (Sweden)

    Cinthia Conceição Matias da Silva

    2016-02-01

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

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

    Science.gov (United States)

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

    2013-07-01

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

  19. Attraction Effects in Honorific Agreement in Korean

    Science.gov (United States)

    Kwon, Nayoung; Sturt, Patrick

    2016-01-01

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

  20. 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).

  1. 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

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

    Directory of Open Access Journals (Sweden)

    Valérie eCoudrain

    2014-06-01

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

  3. Assessing non-target effects and host feeding of the exotic parasitoid Apanteles taragamae, a potential biological control agent of the cowpea pod borer Maruca vitrata

    NARCIS (Netherlands)

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

    2012-01-01

    Apanteles taragamae Viereck is a larval parasitoid introduced in Benin for classical biological control of the cowpea pod borer Maruca vitrata Fabricius. In the laboratory, we evaluated the effects of A. taragamae on non-target herbivore species, and on another parasitoid of M. vitrata, i.e. the egg

  4. Effects of Instructor Attractiveness on Learning.

    Science.gov (United States)

    Westfall, Richard; Millar, Murray; Walsh, Mandy

    2016-01-01

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

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

    Institute of Scientific and Technical Information of China (English)

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

    2008-01-01

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

  6. Direct and indirect sublethal effects of Galanthus nivalis agglutinin (GNA) on the development of a potato-aphid parasitoid, Aphelinus abdominalis (Hymenoptera: Aphelinidae).

    Science.gov (United States)

    Couty, A; de la Viña, G; Clark, S J.; Kaiser, L; Pham-Delègue, M -H.; Poppy, G M.

    2001-06-01

    Snowdrop lectin (Galanthus nivalis agglutinin, GNA), has been shown to confer partial resistance to two potato aphids Myzus persicae and Aulacorthum solani, when incorporated in artificial diet and/or expressed in transgenic potato. First-tier laboratory-scale experiments were conducted to assess the potential effect of GNA on the aphid parasitoid Aphelinus abdominalis. GNA (0.1% w/v) was successfully delivered to Macrosiphum euphorbiae via artificial diet and induced a reduced growth rate and increased mortality compared to aphids fed a control diet. As aphid parasitoid larvae are endophagous, they may be exposed to GNA during their larval development and potential "chronic toxicity" on A. abdominalis was investigated. The amounts of GNA present in aphid and parasitoid tissues were estimated by western blotting. Results suggest that parasitoids excrete most of the GNA ingested. Sublethal effects of GNA on several parasitoid fitness parameters (parasitism success, parasitoid development and size, emergence success, progeny survival and sex ratio) were studied. No direct detrimental effect of GNA on A. abdominalis was observed. However, GNA had an indirect host-size-mediated effect on the sex ratio and the size of parasitoids developing in GNA-fed aphids. This work highlights the need to determine the exact "causes and effects" when assessing the ecological impact of transgenic plants on non-target beneficial insects. Such bioassays form the basis of a tiered risk assessment moving from laboratory studies assessing individuals towards field-scale experiments assessing populations.

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

    Directory of Open Access Journals (Sweden)

    Nicole Wäschke

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

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

    Institute of Scientific and Technical Information of China (English)

    MUHAMMADHASEEB; HIROSHIAMANO; TONG-XIANLIU

    2005-01-01

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

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

    Science.gov (United States)

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

    2016-01-01

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

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

    Science.gov (United States)

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

    2016-01-01

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

  11. Effects of sexual dimorphism on facial attractiveness.

    Science.gov (United States)

    Perrett, D I; Lee, K J; Penton-Voak, I; Rowland, D; Yoshikawa, S; Burt, D M; Henzi, S P; Castles, D L; Akamatsu, S

    1998-08-27

    Testosterone-dependent secondary sexual characteristics in males may signal immunological competence and are sexually selected for in several species. In humans, oestrogen-dependent characteristics of the female body correlate with health and reproductive fitness and are found attractive. Enhancing the sexual dimorphism of human faces should raise attractiveness by enhancing sex-hormone-related cues to youth and fertility in females, and to dominance and immunocompetence in males. Here we report the results of asking subjects to choose the most attractive faces from continua that enhanced or diminished differences between the average shape of female and male faces. As predicted, subjects preferred feminized to average shapes of a female face. This preference applied across UK and Japanese populations but was stronger for within-population judgements, which indicates that attractiveness cues are learned. Subjects preferred feminized to average or masculinized shapes of a male face. Enhancing masculine facial characteristics increased both perceived dominance and negative attributions (for example, coldness or dishonesty) relevant to relationships and paternal investment. These results indicate a selection pressure that limits sexual dimorphism and encourages neoteny in humans. PMID:9732869

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

    NARCIS (Netherlands)

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

    2001-01-01

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

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

    NARCIS (Netherlands)

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

    2001-01-01

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

  14. Effects of elevated CO2 and plant genotype on interactions among cotton, aphids and parasitoids

    Institute of Scientific and Technical Information of China (English)

    Yu-Cheng Sun; Li Feng; Feng Gao; Feng Ge

    2011-01-01

    Effects of CO2 level (ambient vs.elevated) on the interactions among three cotton (Gossypium hirsutum) genotypes,the cotton aphid (Aphis gossypii Glover),and its hymenoptera parasitoid (Lysiphlebiajaponica Ashrnead) were quantified.It was hypothesized that aphid-parasitoid interactions in crop systems may be altered by elevated CO2,and that the degree of change is influenced by plant genotype.The cotton genotypes had high (M9101),medium (HZ401) and low (ZMS 13) gossypol contents,and the response to elevated CO2 was genotype-specific.Elevated CO2 increased the ratio of total non-structural carbohydrates to nitrogen (TNC:N) in the high-gossypol genotype and the mediumgossypol genotype.For all three genotypes,elevated CO2 had no effect on concentrations of gossypol and condensed tannins.A.gossypii fitness declined when aphids were reared on the high-gossypol genotype versus the low-gossypol genotype under elevated CO2.Furthermore,elevated CO2 decreased the developmental time of L.japonica associated with the high-gossypol genotype and the low-gossypol genotype,but did not affect parasitism or emergence rates.Our study suggests that the abundance of A.gossypii on cotton will not be directly affected by increases in atmospheric CO2.We speculate that A.gossypii may diminish in pest status in elevated CO2 and high-gossypol genotype environments because of reduced fitness to the high-gossypol genotype and shorter developmental time of L.japonica.

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

    Science.gov (United States)

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

    2011-12-01

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

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

    Institute of Scientific and Technical Information of China (English)

    汪鹏; 娄永根

    2013-01-01

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

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

    OpenAIRE

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

    2013-01-01

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

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

    OpenAIRE

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

    2010-01-01

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

  19. 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

  20. 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.

  1. Effects of Tattoos on Perceptions of Credibility and Attractiveness

    OpenAIRE

    Seiter, John S.; Hatch, Sarah

    2005-01-01

    This study examined the effects of tattooing on perception of a male's and a female's credibility and attractiveness. 74 undergraduates viewed a photograph of a tattooed or nontattooed male or female model and then rated dimensions of the models' credibility and attractiveness. Analysis indicated that, although the models' attractiveness ratings were not affected by having a tattoo, their credibility ratings were generally lower when wearing a tattoo than when not wearing one.

  2. The Effects of Attractiveness and Status on Personality Evaluation

    OpenAIRE

    Stefano Tartaglia; Chiara Rollero

    2015-01-01

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

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

    Institute of Scientific and Technical Information of China (English)

    Elie A.Dannon; Manuele Tamò; Cyriaque Agboton; Arnold van Huis; Marcel Dicke

    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 parasitized when in the second instar.Maruca vitrata larvae were fed with flowers of four legumes,that is,Vigna unguiculata (cowpea),Sesbania rostrata,Lonchocarpus sericeus and Pterocarpus santalinoides,or an artificial diet both before and after parasitization.The parasitoid did not develop in hosts feeding on L.sericeus or V.unguiculata at 25℃,or on P.santalinoides at 25℃ or 29℃.Apanteles taragaraae had the shortest development time on artificial diet at both 25℃ and 29℃ while the longest development time was recorded on L.sericeus at 29℃.Female wasps took longer to develop compared to males at the two temperatures,regardless of the feeding substrate of their host.The longevity of the wasps at 25℃ varied among feeding substrates,but not at 29℃.Survival rate of parasitized larvae depends on the feeding substrate.Moreover,infection of host larvae with Maruca vitrata multi-nucleopolyhedrovirus (MaviMNPV) killed larger proportions of parasitized larvae at 25℃ than at 29℃,which was likely caused by the difference in parasitoid developmental rate.The proportion of female parasitoids was lowest on L.sericeus.The daily fecundity showed a nonlinear trend regardless of the feeding substrate,indicating that A.taragaraae is a pro-ovigenic species.The data support the slow growth-high mortality hypothesis.

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

    Science.gov (United States)

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

    2015-10-01

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

  5. 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...

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

    Science.gov (United States)

    O'Reilly, Maria T.

    1987-01-01

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

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

    Science.gov (United States)

    Longo, Laura C.; Ashmore, Richard D.

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

  8. Effects of Type of Information Upon Interpersonal Attraction

    Science.gov (United States)

    Duck, Steven W.; Craig, Gordon

    1975-01-01

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

  9. 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.

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

    Science.gov (United States)

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

  11. The Effects of Attractiveness and Status on Personality Evaluation

    Directory of Open Access Journals (Sweden)

    Stefano Tartaglia

    2015-11-01

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

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

    Science.gov (United States)

    Tartaglia, Stefano; Rollero, Chiara

    2015-11-01

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

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

    Science.gov (United States)

    Barak, Azy; And Others

    1982-01-01

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

  14. 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 para

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

    Science.gov (United States)

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

    2016-05-01

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

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

    Science.gov (United States)

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

    2016-05-01

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

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

    Directory of Open Access Journals (Sweden)

    Komivi S Akutse

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

  18. 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

  19. Effect of insecticides on mealybug destroyer (Coleoptera: Coccinellidae) and parasitoid Leptomastix dactylopii (Hymenoptera: Encyrtidae), natural enemies of citrus mealybug (Homoptera: Pseudococcidae).

    Science.gov (United States)

    Cloyd, Raymond A; Dickinson, Amy

    2006-10-01

    In this study, we measured, under laboratory conditions, the direct and indirect effects of insecticides on mealybug destroyer, Cryptolaemus montrouzieri Mulsant (Coleoptera: Coccinellidae), and parasitoid Leptomastix dactylopii Howard (Hymenoptera: Encyrtidae), natural enemies of citrus mealybug, Planococcus citri (Risso) (Homoptera: Pseudococcidae). The adult stages of both natural enemies were exposed to sprays of the insecticides buprofezin, pyriproxyfen, flonicamid, acetamiprid, dinotefuran, and clothianidin at label-recommended rates to assess direct mortality after 24, 48, and 72 h, respectively. The effects of the insecticides on L. dactylopii parasitization rate and percentage of parasitoid emergence also were monitored using the label and 4x the recommended label rate. Dinotefuran was extremely detrimental to the adult parasitoid at the label rate with 100% mortality after 24 h. Buprofezin, pyriproxyfen, and flonicamid were not harmful to L. dactylopii when applied at the label rate. At 4x the recommended label rate, dinotefuran, acetamiprid, and clothianidin were all harmful to the parasitoid with 100% mortality 72 h after application. Both buprofezin and flonicamid were not toxic to L. dactylopii with 100% adult survival after 72 h. Pyriproxyfen and flonicamid, at both the label and 4x the recommended label rate, did not negatively affect L. dactylopii parasitization rate or percentage of parasitoid emergence. Acetamiprid, dinotefuran, and clothianidin were toxic to C. montrouzieri adults with 100% mortality after 48 h, whereas buprofezin, pyriproxyfen, and flonicamid demonstrated minimal (10-20% mortality after 48 h) harmful effects to the predator. Based on the results from our study, the indirect effects of the insect growth regulator (IGR) buprofezin were not decisive; however, the IGR pyriproxyfen and the insecticide flonicamid were not directly or indirectly harmful to the predator C. montrouzieri and parastioid L. dactylopii, indicating that

  20. Effects of dietary nicotine on the development of an insect herbivore, its parasitoid and secondary hyperparasitoid over four trophic levels

    NARCIS (Netherlands)

    Harvey, J.A.; Dam, van N.M.; Witjes, L.M.A.; Soler, R.; Gols, R.

    2007-01-01

    1. Allelochemicals in herbivore diet are known to affect the development of higher trophic levels, such as parasitoids and predators. 2. This study examines how differing levels of nicotine affects the development of a herbivore, its parasitoid and secondary hyperparasitoid over four trophic levels.

  1. 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

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

    International Nuclear Information System (INIS)

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

  3. 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.

  4. The effect of meat consumption on body odor attractiveness.

    Science.gov (United States)

    Havlicek, Jan; Lenochova, Pavlina

    2006-10-01

    Axillary body odor is individually specific and potentially a rich source of information about its producer. Odor individuality partly results from genetic individuality, but the influence of ecological factors such as eating habits are another main source of odor variability. However, we know very little about how particular dietary components shape our body odor. Here we tested the effect of red meat consumption on body odor attractiveness. We used a balanced within-subject experimental design. Seventeen male odor donors were on "meat" or "nonmeat" diet for 2 weeks wearing axillary pads to collect body odor during the final 24 h of the diet. Fresh odor samples were assessed for their pleasantness, attractiveness, masculinity, and intensity by 30 women not using hormonal contraceptives. We repeated the same procedure a month later with the same odor donors, each on the opposite diet than before. Results of repeated measures analysis of variance showed that the odor of donors when on the nonmeat diet was judged as significantly more attractive, more pleasant, and less intense. This suggests that red meat consumption has a negative impact on perceived body odor hedonicity. PMID:16891352

  5. The effect of direct interspecific competition on patch exploitation strategies in parasitoid wasps.

    Science.gov (United States)

    Mohamad, Rihab; Wajnberg, Eric; Monge, Jean-Paul; Goubault, Marlène

    2015-01-01

    The presence of competitors may affect the pay-off of individuals' foraging strategies. They should therefore modify their resource exploitation decisions accordingly. In such a direct competition situation, theory predicts that individuals should stay longer on a resource patch than when foraging alone. However, models predicting patch residence time focus on intraspecific competition without agonistic interactions. Here, we investigate the patch use strategies of females of two parasitoid species, Eupelmus vuilleti and Dinarmus basalis, attacking the same host, Callosobruchus maculatus, knowing that D. basalis is more aggressive and can exclude E. vuilleti during pairwise contests for single hosts. Our results showed that time allocation and oviposition strategies differed in relation to the species and type of competition (i.e., presence/absence of competitor, simultaneous/sequential female introduction or resident/intruder female). Eupelmus vuilleti females tended to wait in the patch surroundings for D. basalis females' departure to return and exploit hosts parasitized by the opponent (after destruction of her eggs). In contrast, D. basalis females tended to self-superparasitize and stay motionless near the hosts. After detecting an E. vuilleti female entering the patch, they attacked and chased her permanently from the patch. Females of both species spent less time in the patch when faced with a competitor than when alone. This study is the first to test the influence of direct interspecific competition and arrival order on patch exploitation strategies in parasitoid species, and highlights the necessity to include agonistic behaviors in theoretical models predicting optimal patch residence time in competitive situations.

  6. Is Beauty Talent? Sex Interaction in the Attractiveness Halo Effect.

    Science.gov (United States)

    Kaplan, Robert M.

    Male and female subjects judged an essay purportedly written by an attractive or an unattractive female author. The attractive author was rated as significantly more talented by male judges. Female judges rated the attractive author less talented although this difference was not statistically significant. A second experiment concerned ratings by…

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

    Science.gov (United States)

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

    2016-07-01

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

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

    Institute of Scientific and Technical Information of China (English)

    CHENG Ze

    2011-01-01

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

  9. Self-attraction effect and correction on three absolute gravimeters

    CERN Document Server

    Biolcati, Emanuele; Germak, Alessandro

    2012-01-01

    The perturbations of the gravitational field due to the mass distribution of an absolute gravimeter have been studied. The so called Self Attraction Effect (SAE) is crucial for the measurement accuracy, especially for the International Comparisons, and for the uncertainty budget evaluation. Three instruments have been analysed: MPG-2, FG5-238 and IMPG-02. The SAE has been calculated using a numerical method based on FEM simulation. The observed effect has been treated as an additional vertical gravity gradient. The correction (SAC) to be applied to the computed g value has been associated with the specific height level, where the measurement result is typically reported. The magnitude of the obtained corrections is of order 1E-8 m/s2.

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

    Science.gov (United States)

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

    1991-04-01

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

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

    Science.gov (United States)

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

    1991-04-01

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

  12. 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.

  13. 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. PMID:25007759

  14. Effects of transgenic Cry1A+CpTI cotton and Cry1Ac toxin on the parasitoid, Campoketis chlorideae (Hymenoptera:Ichneumonidae)

    Institute of Scientific and Technical Information of China (English)

    XIAO-XIALIU; CHANG-GUISUN; QING-WENZHANG

    2005-01-01

    The effect oftransgenic double genes, Cry1A + CpTlcotton and Cry1Ac toxin on the parasitoid, Carnpoketis chlorideae Uchida of cotton bollworm, Helicoverpa armigera (Hübner), was investigated in the laboratory. Helicoverpa armigera larvae when in the first,second and third instar could not survive if fed on transgenic cotton leaves. Consequently,C. chlorideae larvae could not complete their development if parasitizing on such hosts.After H. armigera larvae were reared on transgenic or traditional cotton leaves for 12-48 hours, they were parasitized by C. chlorideae females. Parasitized larvae continued to feed on transgenic or traditional cotton for 12-48 h. The present results showed that the body weight of larvae of the parasitoids were significantly reduced when parasitized hosts fed on transgenic cotton leaves compared to those fed on traditional cotton. Duration of egg and larvae stage were significantly prolonged, pupal and adult weight of C. chloridae was decreased when the host larvae fed on transgenic cotton leaves longer than 48 h. The development duration of C. chlorideae pupae on the hosts fed on transgenic cotton leaves in each treatment was not significantly different from those of controls. The longevity of parasitoid females and males fed with a solution containing Cry1Ac toxin was not significantly different with that of the control.

  15. 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.

  16. 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

  17. 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…

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

    Science.gov (United States)

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

    1997-01-01

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

  19. Tree phylogenetic diversity promotes host-parasitoid interactions.

    Science.gov (United States)

    Staab, Michael; Bruelheide, Helge; Durka, Walter; Michalski, Stefan; Purschke, Oliver; Zhu, Chao-Dong; Klein, Alexandra-Maria

    2016-07-13

    Evidence from grassland experiments suggests that a plant community's phylogenetic diversity (PD) is a strong predictor of ecosystem processes, even stronger than species richness per se This has, however, never been extended to species-rich forests and host-parasitoid interactions. We used cavity-nesting Hymenoptera and their parasitoids collected in a subtropical forest as a model system to test whether hosts, parasitoids, and their interactions are influenced by tree PD and a comprehensive set of environmental variables, including tree species richness. Parasitism rate and parasitoid abundance were positively correlated with tree PD. All variables describing parasitoids decreased with elevation, and were, except parasitism rate, dependent on host abundance. Quantitative descriptors of host-parasitoid networks were independent of the environment. Our study indicates that host-parasitoid interactions in species-rich forests are related to the PD of the tree community, which influences parasitism rates through parasitoid abundance. We show that effects of tree community PD are much stronger than effects of tree species richness, can cascade to high trophic levels, and promote trophic interactions. As during habitat modification phylogenetic information is usually lost non-randomly, even species-rich habitats may not be able to continuously provide the ecosystem process parasitism if the evolutionarily most distinct plant lineages vanish. PMID:27383815

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

    Science.gov (United States)

    Wu, Yu-Chi

    2012-02-01

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

  1. 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 cue

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

    Science.gov (United States)

    Re, Daniel E; Perrett, David I

    2014-01-01

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

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

    Science.gov (United States)

    Re, Daniel E; Perrett, David I

    2014-01-01

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

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

    Science.gov (United States)

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

    1980-04-01

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

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

    Science.gov (United States)

    Jones, Alex L; Kramer, S S

    2015-01-01

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

  6. 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.

  7. Effective attractive potential between identical dielectric molecules via Lifshitz theory

    Institute of Scientific and Technical Information of China (English)

    CHEN; Laiwen

    2001-01-01

    [1]London, F., The general theory of molecular forces, Trans. Faraday Soc., 937, 33: 8.[2]Lifshitz, E. M., The theory of molecular attractive forces between solids, Sov. Phys., JETP, 956, 2: 73, and references therein.[3]Dzyaloshinski, I. E., Lifshitz, E. M., Pitaeveskiǐ, L. P., The general theory of van der Waals forces, Adv. Phys., 96, 0: 65.[4]Linder, B., Reaction-field techniques and their applications to intermolecular forces, Adv. Chem. Phys., 967, 2: 225.[5]McLachlan, A. D., Retarded dispersion forces in dielectrics at finite temperature, Proc. Roy. Soc., 963, A274: 80.[6]Israelachvili, J. N., The calculations of van der Waals dispersion forces between macroscopic bodies, Proc. Roy. Soc. (London), 972, A33: 38.[7]Nir, S., van der Waals interactions between surfaces of biological interest, Prog. Surf. Sci., 976, 8: .[8]van Oss, C. J., Interfacial Lifshitz-van der Waals and polar interactions in macroscopic systems, Chem. Rev., 988, 88: 927.[9]Rytov, S. M., Kravtsov, Y. A., Tatarskii, V. I., Principles of Statistical Radiophysics 3: Elements of Random Fields, Berlin: Springer-Verlag, 989, 09—73.[10]Rytov, S. M., Correlation theory of electric fluctuations and thermal radiation, in Advances in Physical Sciences, State Publishing House for Theoretical and Technical Literature (eds. Blokhintsev D. I., Veksler, V. I, Konobeevskii, S. T. et al.), Moscow, 95Vol. 63, Part II: 89—92.[11]Israelachvili, J. N., Van der Waals forces in biological systems, Q. Rev. Biophys., 974, 6: 34.[12]Lifshitz, E. M., Pitaeveskiǐ, L. P., Statistical Physics: part 2——Theory of the Condensed State. 2nd ed. Oxford: Pergamon Press, 980. 34—359.[13]Lifshitz, E. M., Theory of molecular attraction force between condensed bodies, in Perspectives in Theoretical Physics: the Collected Papers of E. M., (ed. Pitaeveskiǐ L P), Lifshitz-Oxford: Pergamon Press, 9933—37.[14]Nir, S., Adams, S., Rein, R., Determination of dielectric

  8. Effect of Parasitoid: Host Ratio and Parasitoid and Host Group Size on Fitness of Spathius galinae (Hymenoptera: Braconidae), a Parasitoid of Emerald Ash Borer (Coleoptera: Buprestidae): Implications for Mass-Rearing

    Science.gov (United States)

    Producing insect natural enemies in laboratories or insectaries for biological pest control is often expensive, and developing cost-effective rearing techniques is a goal of many biological control programs. Spathius galinae Belokobylskij and Strazenac (Hymenoptera: Braconidae), a recently described...

  9. 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.

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

    CERN Document Server

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

    2015-01-01

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

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

    Science.gov (United States)

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

    2010-01-01

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

  12. Evaluation of a young child's behavior: effects of attractiveness and sex.

    Science.gov (United States)

    Horvath, T; MacDonald, E L

    1989-12-01

    Facial drawings of 2- or 4-yr.-old boys or girls differing in attractiveness were attached to an episode which depicted a mild misbehavior. Neither the attribution of responsibility for the behavior nor the choice of an indulgent vs punitive response was associated with the child's attractiveness, sex, or age. These findings suggest that the halo effects of attractiveness discriminations may not be fully operative at these ages. PMID:2608386

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

    NARCIS (Netherlands)

    Kos, M.; Houshyani Hassanzadeh, B.; Overeem, A.J.; Bouwmeester, H.J.; Weldegergis, B.T.; Loon, van 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 pursue

  14. 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

  15. 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.

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

    Science.gov (United States)

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

    1998-01-01

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

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

    Science.gov (United States)

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

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

    Science.gov (United States)

    Wiener, Seymour; And Others

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

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

    Science.gov (United States)

    Vargas, Alice M.; Borkowski, John G.

    1983-01-01

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

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

    Directory of Open Access Journals (Sweden)

    Hasan Safdel

    2014-12-01

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

  1. 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…

  2. Packing of Fruit Fly Parasitoids for Augmentative Releases

    Directory of Open Access Journals (Sweden)

    Pablo Montoya

    2012-09-01

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

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

    Science.gov (United States)

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

    2014-06-01

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

  4. Effects of rearing host species on the host-feeding capacity and parasitism of the whitefly parasitoid Encarsia formosa.

    Science.gov (United States)

    Dai, Peng; Ruan, Changchun; Zang, Liansheng; Wan, Fanghao; Liu, Linzhou

    2014-01-01

    Parasitoids of the Encarsia genus (Hymenoptera: Aphelinidae) are important biological control agents against whiteflies. Some of the species in this genus not only parasitize their hosts, but also kill them through host feeding. The whitefly parasitoid, Encarsia formosa Gahan, was examined to determine whether the rearing host species affects its subsequent host-feeding capacity and parasitism. E. formosa wasps were reared on Trialeurodes vaporariorum (Westwood) (Hemiptera: Aleyrodidae) and Bemisia tabaci (Gennadius) 'Q', and their subsequent host-feeding capacity and parasitism of T. vaporariorum and B. tabaci were examined. E. formosa reared on T. vaporariorum were significantly larger in body size than those reared on B. tabaci, but these wasps killed a similar number of whitefly nymphs by host feeding when they attacked the same host species on which they were reared. Regardless of the species on which it was reared, E. formosa fed significantly more on the B. tabaci nymphs than on the T. vaporariorum nymphs. The number of whitefly nymphs parasitized by E. formosa differed between the wasps reared on T. vaporariorum and those reared on B. tabaci depending on which whitefly species was offered as a host. In addition, the wasps reared on T. vaporariorum parasitized significantly more on T. vaporariorum than those reared on B. tabaci. The wasps reared on B. tabaci, however, parasitized similar numbers of whiteflies of both host species. The results indicated that the host-feeding capacity of E. formosa was affected more by the host species attacked than by the rearing host species, but the parasitism was affected by the host species attacked and the rearing host species. Generally, E. formosa reared on T. vaporariorum killed more T. vaporariorum nymphs by parasitism and host feeding than those reared on B. tabaci. Additionally, a similar number of B. tabaci nymphs were killed by parasitism and host feeding regardless of the rearing host species. Currently

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

    CERN Document Server

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

    2006-01-01

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

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

    Science.gov (United States)

    Carroo, Agatha W.; Mozingo, R.

    1989-01-01

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

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

    Science.gov (United States)

    Tajima, T

    2000-10-01

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

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

    Science.gov (United States)

    Tajima, T

    2000-10-01

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

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

    Science.gov (United States)

    Bell, P A

    1975-01-01

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

  10. Multisensory foraging by hymenopterous parasitoids.

    OpenAIRE

    Wäckers, F.L.

    1994-01-01

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

  11. 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.

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

    Science.gov (United States)

    Thornton, Bill; Ryckman, Richard M.

    1991-01-01

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

  13. 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

  14. 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

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

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    Jianing Wei

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

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

    Science.gov (United States)

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

    2003-08-01

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

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

    Science.gov (United States)

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

    2016-03-23

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

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

    Science.gov (United States)

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

    2016-03-23

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

  19. The effect of corporate image on the formation of customer attraction

    Directory of Open Access Journals (Sweden)

    Reza Koohjani Gouji

    2016-10-01

    Full Text Available This paper examines the relationship of corporate image with customer attraction in Irancell Telecommunications Services Company in city of Ahvaz, Iran. The study uses a sample of 384 randomly selected people who use the firm’s services. Measuring tools for corporate image and customer attraction are an 18-item questionnaire of Rampersad (2001 [Rampersad, H. (2001. 75 painful questions about your customer satisfaction. the TQM Magazine, 13(5, 341-347.] and a 14-item questionnaire of Geib (2005 [Geib, M. (2005. Architecture for customer relationship management to attract and retain customers approaches in financial services, IEEE, Proceedings of the 38th Hawaii International Conference on System Sciences.], respectively. Results of regression analysis showed that there was a significant relationship between corporate image and attracting customers in Irancell firm. In addition, dimensions of corporate image including experience, character, competence, quality, differentiation, cost, technology, and culture and cognition increase customer attraction to the company. On the other hand, component of culture has the most effect on attracting customers in this firm.

  20. 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)

  1. Partial aphid resistance in lettuce negatively affects parasitoids.

    Science.gov (United States)

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

    2014-10-01

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

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

    International Nuclear Information System (INIS)

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

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

    Science.gov (United States)

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

    2007-03-01

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

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

    Science.gov (United States)

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

    2007-03-01

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

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

    Science.gov (United States)

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

    2015-01-01

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

  6. 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.

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

    Science.gov (United States)

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

    2014-12-01

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

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

    Science.gov (United States)

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

    2014-12-01

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

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

    International Nuclear Information System (INIS)

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

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

    NARCIS (Netherlands)

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

    2011-01-01

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

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

    NARCIS (Netherlands)

    Dijkstra, P; Buunk, BP; Blanton, H

    2000-01-01

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

  12. Lobesia botrana larvae develop faster in the presence of parasitoids.

    Directory of Open Access Journals (Sweden)

    Fanny Vogelweith

    Full Text Available To combat parasitism hosts often rely on their immune system, which is the last line of defense. However, the immune system may not always be effective, and other non-immunological defenses might be favored to reduce the cost of parasite infection. Here we report that larvae of the moth Lobesia botrana can rapidly accelerate their development and reach maturity earlier in response to cues perceived at a distance from parasitoids. Such a phenotypically plastic life history shift, induced by the perception of deadly enemies in the environment, is likely to be an adaptive defensive strategy to prevent parasitoid attack, and has important implications in host-parasite dynamics.

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

    Science.gov (United States)

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

    1999-11-01

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

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

    Science.gov (United States)

    Miyake, K; Zuckerman, M

    1993-09-01

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

  15. 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.

  16. 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.

  17. 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

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

    Science.gov (United States)

    Germain, Ph

    2010-07-28

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

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

    Science.gov (United States)

    Germain, Ph.

    2010-07-01

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

  20. Multisensory foraging by hymenopterous parasitoids.

    NARCIS (Netherlands)

    Wäckers, F.L.

    1994-01-01

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

  1. Effects of shape parameters on the attractiveness of a female body.

    Science.gov (United States)

    Fan, J; Dai, W; Qian, X; Chau, K P; Liu, Q

    2007-08-01

    Various researchers have suggested that certain anthropometric ratios can be used to measure female body attractiveness, including the waist to hip ratio, Body Mass Index (BMI), and the body volume divided by the square of the height (Volume-Height Index). Based on a wide range of female subjects and virtual images of bodies with different ratios, Volume-Height Index was found to provide the best fit with female body attractiveness, and the effect of Volume-Height Index can be fitted with two half bell-shaped exponential curves with an optimal Volume-Height Index at 14.2 liter/m2. It is suggested that the general trend of the effect of Volume-Height Index may be culturally invariant, but the optimal value of Volume-Height Index may vary from culture to culture. In addition to Volume-Height Index, other body parameters or ratios which reflect body proportions and the traits of feminine characteristics had smaller but significant effects on female body attractiveness, and such effects were stronger at optimum Volume-Height Index. PMID:17918555

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

    CERN Document Server

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

    2016-01-01

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

  3. Nonhost diversity and density reduce the strength of parasitoid-host interactions.

    Science.gov (United States)

    Kehoe, Rachel; Frago, Enric; Barten, Catherin; Jecker, Flurin; van Veen, Frank; Sanders, Dirk

    2016-06-01

    The presence of nonprey or nonhosts is known to reduce the strength of consumer- resource interactions by increasing the consumer's effort needed to find its resource. These interference effects can have a stabilizing effect on consumer-resource dynamics, but have also been invoked to explain parasitoid extinctions. To understand how nonhosts affect parasitoids, we manipulated the density and diversity of nonhost aphids using experimental host-parasitoid communities and tested how this affects parasitation efficiency of two aphid parasitoid species. To further study the behavioral response of parasitoids to nonhosts, we tested for changes in parasitoid time allocation in relation to their host-finding strategies. The proportion of successful attacks (attack rate) in both parasitoid species was reduced by the presence of nonhosts. The parasitoid Aphidius megourae was strongly affected by increasing nonhost diversity with the attack rate dropping from 0.39 without nonhosts to 0.05 with high diversity of nonhosts, while Lysiphlebus fabarum responded less strongly, but in a more pronounced way to an increase in nonhost density. Our experiments further showed that increasing nonhost diversity caused host searching and attacking activity levels to fall in A. megourae, but not in L. fabarum, and that A. megourae changed its behavior after a period of time in the presence of nonhosts by increasing its time spent resting. This study shows that nonhost density and diversity in the environment are crucial determinants for the strength of consumer-resource interactions. Their impact upon a consumer's efficiency strongly depends on its host/prey finding strategy as demonstrated by the different responses for the two parasitoid species. We discuss that these trait-mediated indirect interactions between host and nonhost species are important for community stability, acting either stabilizing or destabilizing depending on the level of nonhost density or diversity present. PMID

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

    OpenAIRE

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

    2003-01-01

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

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

    Science.gov (United States)

    Langlois, Judith H.; Stephan, Cookie

    1977-01-01

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

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

    Institute of Scientific and Technical Information of China (English)

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

    2009-01-01

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

  7. Leaf-Cutter Ant Parasitoids: Current Knowledge

    OpenAIRE

    Patricia J. Folgarait

    2013-01-01

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

  8. 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.

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

    Science.gov (United States)

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

    2015-05-01

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

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

    Science.gov (United States)

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

    2016-01-01

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

  11. Insect immune resistance to parasitoids

    Institute of Scientific and Technical Information of China (English)

    Yves Carton; Marylène Poirié; Anthony J. Nappi

    2008-01-01

    Insect host-parasitoid interactions involve complex physiological, biochemical and genetic interactions. Against endoparasitoids, immune-competent hosts initiate a blood cell-mediated response that quickly destroys the intruders and envelops them in a multilayered melanotic capsule. During the past decade, considerable progress has been made in identifying some of the critical components of the host response, mainly because of the use of efficient molecular tools. This review examines some of the components of the innate immune response of Drosophila, an insect that has served as an exceptionally good experimental model for studying non-self recognition processes and immune cell signaling mechanisms. Topics considered in this review include hematopoiesis, proliferation and adhesion of hemocytes, melanogenesis and associated cytotoxic molecules, and the genetic aspects of the host-parasitoid interaction.

  12. 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. PMID:26308869

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

    Science.gov (United States)

    Wakgari, W M; Giliomee, J H

    2003-06-01

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

  14. Dynamical System and Nonlinear Regression for Estimate Host-Parasitoid Relationship

    Directory of Open Access Journals (Sweden)

    Ileana Miranda Cabrera

    2010-01-01

    Full Text Available The complex relationships of a crop with the pest, its natural enemies, and the climate factors exist in all the ecosystems, but the mathematic models has studied only some components to know the relation cause-effect. The most studied system has been concerned with the relationship pest-natural enemies such as prey-predator or host-parasitoid. The present paper shows a dynamical system for studying the relationship host-parasitoid (Diaphorina citri, Tamarixia radiata and shows that a nonlinear model permits the estimation of the parasite nymphs using nymphs healthy as the known variable. The model showed the functional answer of the parasitoid, in which a point arrives that its density is not augmented although the number host increases, and it becomes necessary to intervene in the ecosystem. A simple algorithm is used to estimate the parasitoids level using the priori relationship between the host and the climate factors and then the nonlinear model.

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

    Science.gov (United States)

    Baruh, Lemi; Cemalcılar, Zeynep

    2015-09-01

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

  16. 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.

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

    Science.gov (United States)

    Shuntich, Richard J.

    1976-01-01

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

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

    OpenAIRE

    Re, Daniel Edward; Perrett, David Ian

    2014-01-01

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

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

    Science.gov (United States)

    Gilmore, David C.; And Others

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

  20. Fatal attraction

    DEFF Research Database (Denmark)

    Jensen, Kim Ebensgaard

    2012-01-01

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

  1. 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.

  2. 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.

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

    Science.gov (United States)

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

    2016-08-01

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

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

    Science.gov (United States)

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

    2016-04-01

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

  5. Effects of insecticide application on Oracella acuta (Lobdell) (Homoptera: Pseudococcidae) population and its two dominant parasitoids%杀虫剂对湿地松粉蚧种群及其天敌的影响

    Institute of Scientific and Technical Information of China (English)

    孙江华; 张彦周

    2003-01-01

    湿地松粉蚧是于1988年传入我国广东省的一种重要林业外来入侵害虫.现在该害虫在我国的分布面积为35.52万公顷,严重影响着我国南方松林的生长健康.该害虫在其原产地美国南方并不造成大的危害,也不是一种主要害虫.只有当大量应用杀虫剂防治其它害虫时,由于杀死了其天敌,湿地松粉蚧种群才会明显增长.为控制这一外来入侵害虫,中美两国于1995年开展了从美国引进天敌防治广东省湿地松粉蚧的林业合作项目.本文报道了1996~1997年间在美国南方三个种子园使用杀虫剂防治球果种实害虫时,杀虫剂对湿地松粉蚧种群及其两种主要天敌有明显的影响,这也间接地说明了寄生性天敌对湿地松粉蚧在自然条件下的控制作用.相关分析显示湿地松粉蚧种群数量与其天敌是密切相关的,但杀虫剂可以打破这种平衡.这一方面说明从美国引进天敌防治湿地松粉蚧是可行的,另一方面也显示在美国采集湿地松粉蚧天敌应在使用过杀虫剂后的林分中.%The effects of insecticide application on loblolly pine mealybug, Oracella acuta (Lobdell) (Homoptera: Pseudococcidae) and its two dominant parasitoids, Allotropa sp. (Hymenoptera: Platygastridae) and Zarhopalus debarri Sun (Hymenoptera: Encyrtidae), were investigated using yellow sticky traps. Theresultsrevealed that the Oracella population responded positively to the intensityof insecticide use, which had adverse effects on its two parasitoids. In fact, the outbreak of the mealybug was largely due to this adverse effect of insecticides on its parasitoids. Orchards with high intensity use of insecticides resulted higher Oracella population and vice versa. Comparison of three orchards with three levels of insecticide use further demonstrated the effectiveness of the parasitoids in regulating mealybug populations. Significantly more males of Zarhopalus sp. were caught than females indicated a

  6. 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.

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

    Directory of Open Access Journals (Sweden)

    Robin S S Kramer

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

  8. 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...

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

    NARCIS (Netherlands)

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

    2013-01-01

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

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

    NARCIS (Netherlands)

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

    2013-01-01

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

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

    OpenAIRE

    Fisher, Robert J.; Yu Ma

    2014-01-01

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

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

    Science.gov (United States)

    Ha, Thao; Overbeek, Geertjan; Engels, Rutger C M E

    2010-10-01

    The present study examined to what extent adolescent dating desire is based on attractiveness and social status of a potential short-term partner. Further, we tested whether self-perceived mate value moderated the relationship between dating desire and attractiveness of a potential partner. Data were used from a sample of 1,913 adolescents aged 13-18. Participants rated the importance of various characteristics of a potential partner and also participated in an experimental vignette study in which dating desire was measured with either low or high attractive potential partners having either a high or low social status. The results showed that boys rated attractiveness as more important than girls, while social status was rated as relatively unimportant by both sexes. In addition, in the experimental vignette study, it was found that attractiveness was the primary factor for boys' dating desire. Only when a potential partner was attractive, social status became important for boys' dating desire. For girls, on the other hand, it appeared that both attractiveness and social status of a potential partner were important for their dating desire. Finally, boys and girls who perceived themselves as having a high mate value showed more dating desire toward an attractive potential partner compared to adolescents who perceived themselves as having a low mate value. The present results extend previous research by showing that attractiveness of a potential partner is important to both adolescent boys and girls, but social status does not strongly affect dating desire during this particular age period. PMID:19830538

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

    OpenAIRE

    Silva, I.M.M.S.

    1999-01-01

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

  14. Artificial nighttime light changes aphid-parasitoid population dynamics

    OpenAIRE

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

    2015-01-01

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

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

    NARCIS (Netherlands)

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

    2010-01-01

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

  16. Perceived Interviewer Expertness and Attractiveness: Effects of Interviewer Behavior and Attire and Interview Setting

    Science.gov (United States)

    Kerr, Barbara A.; Dell, Don M.

    1976-01-01

    Students (N=80) rated the interviewers on a counselor rating form. Only counselor role behavior significantly affected students' perceptions of interviewer attractiveness, while perceptions of expertness seemed to have been affected jointly by role and attire. The relative magnitude of expertness as compared to attractiveness ratings was…

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

    Science.gov (United States)

    Kiire, Satoru

    2016-05-01

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

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

    Science.gov (United States)

    Robinson, Donna L.; And Others

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

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

    Science.gov (United States)

    Sachs, Donald H.

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

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

    NARCIS (Netherlands)

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

    2010-01-01

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

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

    Science.gov (United States)

    Best, Bethia J.; Spector, Paul E.

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

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

    Institute of Scientific and Technical Information of China (English)

    HUANG Guoqiang; DONG Shuanglin; WANG Fang

    2005-01-01

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

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

    Science.gov (United States)

    Huang, Guoqiang; Dong, Shuanglin; Wang, Fang

    2005-01-01

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

  4. Thermodynamically consistent Langevin dynamics with spatially correlated noise predicting frictionless regime and transient attraction effect

    Science.gov (United States)

    Majka, M.; Góra, P. F.

    2016-10-01

    While the origins of temporal correlations in Langevin dynamics have been thoroughly researched, the understanding of spatially correlated noise (SCN) is rather incomplete. In particular, very little is known about the relation between friction and SCN. In this article, starting from the microscopic, deterministic model, we derive the analytical formula for the spatial correlation function in the particle-bath interactions. This expression shows that SCN is the inherent component of binary mixtures, originating from the effective (entropic) interactions. Further, employing this spatial correlation function, we postulate the thermodynamically consistent Langevin equation driven by the Gaussian SCN and calculate the adequate fluctuation-dissipation relation. The thermodynamical consistency is achieved by introducing the spatially variant friction coefficient, which can be also derived analytically. This coefficient exhibits a number of intriguing properties, e.g., the singular behavior for certain types of interactions. Eventually, we apply this new theory to the system of two charged particles in the presence of counter-ions. Such particles interact via the screened-charge Yukawa potential and the inclusion of SCN leads to the emergence of the anomalous frictionless regime. In this regime the particles can experience active propulsion leading to the transient attraction effect. This effect suggests a nonequilibrium mechanism facilitating the molecular binding of the like-charged particles.

  5. Fatal attraction

    DEFF Research Database (Denmark)

    Jensen, Kim Ebensgaard

    2012-01-01

    for redundancies and incongruities in construction networks which enables linguists to take into account details of language use, which would otherwise not be facilitated in complete inheritance models. Secondly, making use of the method of collostructional analysis, the article offers a corpus-based description...... of the use of the Danish ihjel-construction which accounts for patterns of attraction of construction-verb attraction, patterns of productivity, and various types of subconstructions, including item- and item-class-based ones and metaphorical extensions. The description of the ihjel-construction should also...

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

    Science.gov (United States)

    Dunn, Michael J; Searle, Robert

    2010-02-01

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

  7. Self-attraction effect and correction on the T-1 absolute gravimeter

    Science.gov (United States)

    Li, Z.; Hu, H.; Wu, K.; Li, G.; Wang, G.; Wang, L. J.

    2015-12-01

    The self-attraction effect (SAE) in an absolute gravimeter is a kind of systematic error due to the gravitation of the instrument to the falling object. This effect depends on the mass distribution of the gravimeter, and is estimated to be a few microgals (1 μGal  =  10-8 m s-2) for the FG5 gravimeter. In this paper, the SAE of a home-made T-1 absolute gravimeter is analyzed and calculated. Most of the stationary components, including the dropping chamber, the laser interferometer, the vibration isolation device and two tripods, are finely modelled, and the related SAEs are computed. In addition, the SAE of the co-falling carriage inside the dropping chamber is carefully calculated because the distance between the falling object and the co-falling carriage varies during the measurement. In order to get the correction of the SAE, two different methods are compared. One is to linearize the SAE curve, the other one is to calculate the perturbed trajectory. The results from these two methods agree with each other within 0.01 μGal. With an uncertainty analysis, the correction of the SAE of the T-1 gravimeter is estimated to be (-1.9  ±  0.1) μGal.

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

    Directory of Open Access Journals (Sweden)

    Jean-Baptiste Mihoub

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

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

    Science.gov (United States)

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

    2011-01-01

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

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

    Science.gov (United States)

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

    2016-04-01

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

  11. 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

  12. 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.

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

    Science.gov (United States)

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

    2016-01-01

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

  14. Hot or not: the effects of exogenous testosterone on female attractiveness to male conspecifics in the budgerigar.

    Directory of Open Access Journals (Sweden)

    Stefanie E P Lahaye

    Full Text Available An increasing number of studies indicate that not only females but also males can be selective when choosing a mate. In species exhibiting male or mutual mate choice, females may benefit from being attractive. While male attractiveness is often positively influenced by higher plasma levels of the androgenic hormone testosterone, it has been shown that testosterone can masculinise female behavior and morphology in several bird species, potentially rendering them less attractive. In this study, we investigated whether female budgerigars, Melopsittacusundulatus, suffer from increased plasma testosterone levels through a negative effect on their attractiveness to males. We experimentally increased plasma testosterone levels in testosterone-treated females (T-females compared to controls (C-females and allowed males to choose between a T- and a C-female in a two-way choice situation. Although testosterone treatment significantly affected female behavioral and morphological characteristics, males did not show a significant difference in preference between T- and C-females. These results suggest that experimentally increasing testosterone levels in females does not appear to influence male preference during initial mate choice. Our findings indicate that selection for higher levels of testosterone in male budgerigars is probably not constrained by a correlated response to selection causing negative effects on female attractiveness during initial mate choice. Evaluating whether or not a potential constraint may arise from negative testosterone-induced effects on other fitness related traits in females requires further work.

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

    Directory of Open Access Journals (Sweden)

    Qingguo eMa

    2015-03-01

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

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

    Science.gov (United States)

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

    2015-01-01

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

  17. Biological Control of Tortricidae in Tea Fields in Japan Using Insect Viruses and Parasitoids

    Institute of Scientific and Technical Information of China (English)

    Madoka Nakai

    2009-01-01

    Tea is a perennial and evergreen plant. Cultivated tea trees provide a habitat for insect pests and their natural enemies. In Japan, granuloviruses (GVs) have successfully controlled two of the most important pests of tea, Adoxophyes honmai and Homona magnanima (Tortricidae: Lepidoptera). The GVs are produced in vivo and a single application sustains pesticidal efficacy throughout a year, which encompasses 4 to 5 discrete generations of both species. A. honmai and H. magnanima also have various natural enemies, especially hymenopteran parasitoids. Such resident natural enemies also play a role in reducing the pest density in virus-controlled fields, but the effect of virus infection on parasitoids sharing the same host larva has not been well studied. Survival of one of the major parasitoids ofA. honmai, Ascogaster reticulata (Braconidae: Hymenoptera), is reduced by virus infection of the host. Viruses, including GV and entomopoxvirus (EPV), and certain koinobiont endoparasitoids, including A. reticulata, are both known to regulate host endocrinology. However, the GV and EPV have distinct host regulation mechanisms, and consequently have different impacts on the survival of A. retuculata, when A. reticulata parasitizes a host that is infected with either GV or EPV. These additional effects on host regulation displayed by both viruses and parasitoids affect the outcome of virus-parasitoid interactions.

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

    Science.gov (United States)

    Seidman, Gwendolyn; Miller, Olivia S

    2013-01-01

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

  19. 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.

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

    Science.gov (United States)

    Pazhoohi, Farid; Hosseinchari, Masoud

    2014-08-01

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

  1. Effect of ultraviolet photofunctionalisation on the cell attractiveness of zirconia implant materials

    Directory of Open Access Journals (Sweden)

    T Tuna

    2015-01-01

    Full Text Available Ultraviolet (UV light treatment of implant surfaces has been demonstrated to enhance their bioactivity significantly. This study examined the effect of UV treatment of different zirconia surfaces on the response of primary human alveolar bone-derived osteoblasts (PhABO. Disks of two zirconia-based materials with two different surface topographies (smooth, roughened were exposed to UV light. Qualitative and quantitative assessment of PhABO on zirconia surfaces, by means of immunofluorescence, scanning electron microscopy and DNA quantification at 4 and 24 h revealed a higher number of initially attached osteoblasts on UV-treated surfaces. Cell area and perimeter were significantly larger on all UV-treated surfaces (p < 0.05. The proliferation activity was significantly higher on both roughened UV-treated surfaces than on untreated samples at day 3 of culture (p < 0.05. The expression levels of collagen I, osteopontin and osteocalcin at day 14 and alkaline phosphatase activity at day 7 and 14 of culture period were similar among UV-treated and untreated surfaces. Alizarin-Red-Staining at day 21 demonstrated significantly more mineralised nodules on UV-treated samples than on untreated samples. Contact angle measurements and X-ray photoelectron spectroscopy showed that UV light transformed zirconia surfaces from hydrophobic to (super- hydrophilic (p < 0.05 and significantly reduced the atomic percentage of surface carbon. The results showed that UV light pre-treatment of zirconia surfaces changes their physicochemical properties and improves their attractiveness against PhABO, primarily demonstrated by an augmented cell attachment and spreading. This may result in faster healing and better bone-to-implant contact of zirconia implants in vivo following such a pre-treatment.

  2. Is principal component analysis an effective tool to predict face attractiveness? A contribution based on real 3D faces of highly selected attractive women, scanned with stereophotogrammetry.

    Science.gov (United States)

    Galantucci, Luigi Maria; Di Gioia, Eliana; Lavecchia, Fulvio; Percoco, Gianluca

    2014-05-01

    In the literature, several papers report studies on mathematical models used to describe facial features and to predict female facial beauty based on 3D human face data. Many authors have proposed the principal component analysis (PCA) method that permits modeling of the entire human face using a limited number of parameters. In some cases, these models have been correlated with beauty classifications, obtaining good attractiveness predictability using wrapped 2D or 3D models. To verify these results, in this paper, the authors conducted a three-dimensional digitization study of 66 very attractive female subjects using a computerized noninvasive tool known as 3D digital photogrammetry. The sample consisted of the 64 contestants of the final phase of the Miss Italy 2010 beauty contest, plus the two highest ranked contestants in the 2009 competition. PCA was conducted on this real faces sample to verify if there is a correlation between ranking and the principal components of the face models. There was no correlation and therefore, this hypothesis is not confirmed for our sample. Considering that the results of the contest are not only solely a function of facial attractiveness, but undoubtedly are significantly impacted by it, the authors based on their experience and real faces conclude that PCA analysis is not a valid prediction tool for attractiveness. The database of the features belonging to the sample analyzed are downloadable online and further contributions are welcome. PMID:24728666

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

    Directory of Open Access Journals (Sweden)

    Muhammad Tariq

    Full Text Available Multitrophic interactions are likely to be altered by climate change but there is little empirical evidence relating the responses of herbivores and parasitoids to abiotic factors. Here we investigated the effects of drought on an above/below-ground system comprising a generalist and a specialist aphid species (foliar herbivores, their parasitoids, and a dipteran species (root herbivore.We tested the hypotheses that: (1 high levels of drought stress and below-ground herbivory interact to reduce the performance of parasitoids developing in aphids; (2 drought stress and root herbivory change the profile of volatile organic chemicals (VOCs emitted by the host plant; (3 parasitoids avoid ovipositing in aphids feeding on plants under drought stress and root herbivory. We examined the effect of drought, with and without root herbivory, on the olfactory response of parasitoids (preference, plant volatile emissions, parasitism success (performance, and the effect of drought on root herbivory. Under drought, percentage parasitism of aphids was reduced by about 40-55% compared with well watered plants. There was a significant interaction between drought and root herbivory on the efficacy of the two parasitoid species, drought stress partially reversing the negative effect of root herbivory on percent parasitism. In the absence of drought, root herbivory significantly reduced the performance (e.g. fecundity of both parasitoid species developing in foliar herbivores. Plant emissions of VOCs were reduced by drought and root herbivores, and in olfactometer experiments parasitoids preferred the odour from well-watered plants compared with other treatments. The present work demonstrates that drought stress can change the outcome of interactions between herbivores feeding above- and below-ground and their parasitoids, mediated by changes in the chemical signals from plants to parasitoids. This provides a new insight into how the structure of terrestrial

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

    Science.gov (United States)

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

    2013-01-01

    Multitrophic interactions are likely to be altered by climate change but there is little empirical evidence relating the responses of herbivores and parasitoids to abiotic factors. Here we investigated the effects of drought on an above/below-ground system comprising a generalist and a specialist aphid species (foliar herbivores), their parasitoids, and a dipteran species (root herbivore).We tested the hypotheses that: (1) high levels of drought stress and below-ground herbivory interact to reduce the performance of parasitoids developing in aphids; (2) drought stress and root herbivory change the profile of volatile organic chemicals (VOCs) emitted by the host plant; (3) parasitoids avoid ovipositing in aphids feeding on plants under drought stress and root herbivory. We examined the effect of drought, with and without root herbivory, on the olfactory response of parasitoids (preference), plant volatile emissions, parasitism success (performance), and the effect of drought on root herbivory. Under drought, percentage parasitism of aphids was reduced by about 40-55% compared with well watered plants. There was a significant interaction between drought and root herbivory on the efficacy of the two parasitoid species, drought stress partially reversing the negative effect of root herbivory on percent parasitism. In the absence of drought, root herbivory significantly reduced the performance (e.g. fecundity) of both parasitoid species developing in foliar herbivores. Plant emissions of VOCs were reduced by drought and root herbivores, and in olfactometer experiments parasitoids preferred the odour from well-watered plants compared with other treatments. The present work demonstrates that drought stress can change the outcome of interactions between herbivores feeding above- and below-ground and their parasitoids, mediated by changes in the chemical signals from plants to parasitoids. This provides a new insight into how the structure of terrestrial communities may be

  5. Modelling contact spread of infection in host-parasitoid systems: Vertical transmission of pathogens can cause chaos

    OpenAIRE

    Preedy, Katharine F; Schofield, P.G. Pietà G.; Liu, Sijia; Matzavinos, Anastasios; Chaplain, Mark A.J.; Hubbard, Stephen F.

    2009-01-01

    Abstract All animals and plants are, to some extent, susceptible to disease caused by varying combinations of parasites, viruses and bacteria. In this paper, we develop a mathematical model of contact spread infection to investigate the effect of introducing a parasitoid-vectored infection into a one-host-two-parasitoid competition model. We use a system of ordinary differential equations to investigate the separate influences of horizontal and vertical pathogen transmission on a m...

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

    Science.gov (United States)

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

    2016-01-01

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

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

    Science.gov (United States)

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

    2016-01-01

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

  8. 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 impacts of these insecticides on the A. citricola parasitoid. PMID:27146672

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

    Science.gov (United States)

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

    2016-06-01

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

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

    Science.gov (United States)

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

    2003-01-01

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

  11. 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 year

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

    Science.gov (United States)

    Downe, Alan G.; McDougall, Daniel

    1995-01-01

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

  13. 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)

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

    Science.gov (United States)

    Bohman, Eric

    2014-01-01

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

  15. Effects of Counselor Disability Status on Disabled Subjects' Perceptions of Counselor Attractiveness and Expertness.

    Science.gov (United States)

    Strohmer, Douglas C.; Biggs, Donald A.

    1983-01-01

    Studied the influence of client-counselor group membership similarity, counselor reputation cues, and attending behavior on disabled subject's perceptions. Physically disabled adults (N=40) viewed a series of vignettes and rated counselor expertness and attractiveness. Results do not support the belief that client-counselor group membership…

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

    NARCIS (Netherlands)

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

    2003-01-01

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

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

    OpenAIRE

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

    2012-01-01

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

  18. The Smell of Success?—The Impact of Perfume-Gender Congruency on Ratings of Attraction and the Halo Effect

    OpenAIRE

    Marinova, Radost; Moss, Mark

    2014-01-01

    Research into the concept of attraction has indicated the existence of olfactory influences that go beyond pheromonal level. Synthetic fragrances have been found to affect not only perception of attraction, but also attribution of beauty-unrelated intrinsic characteristics. The present study aimed to examine the impact of perfume-gender congruency on ratings of attractiveness and any perfume-generated halo effect. Male faces categorized as low, medium and high attractiveness were rated by 36 ...

  19. Age-specific interaction between the parasitoid, Encarsia formosa and its host, the silverleaf whitefly, Bemisia tabaci (Strain B).

    Science.gov (United States)

    Hu, Jing S; Gelman, Dale B; Blackburn, Michael B

    2003-01-01

    The effect of hostage, the instar of Bemisia tabaci (Gennadius) parasitized, on the growth and development of Encarsia formosa (Gahan) was studied. E. formosa was able to parasitize and complete its life cycle no matter which instar of B. tabaci (Strain B), [also identified as B. argentifolii (Bellows and Perring)], was provided for oviposition, but parasitoid development was significantly slower when 1st or 2nd instar B. tabaci rather than 3rd or 4th instars were parasitized. Host age influenced the day on which E. formosa nymphs hatching from eggs was first observed. Mean embryonic development was significantly longer when 1st (5.4 days) rather than 2nd, 3rd or 4th instars (4.1, 3.4 and 3.5 days, respectively) were parasitized. The duration of the 1st instar parasitoid and the pupa, but not the 2nd or 3rd instar parasitoid, were also significantly greater when 1st instars were parasitized than when older host instars were parasitized. Interestingly, no matter which instar was parasitized, the parasitoid did not molt to the 3rd instar until the 4th instar host had reached a depth of about 0.23 mm (Stage 4-5) and had initiated the nymphal-adult molt and adult development. Histological studies revealed that whitefly eye and wing structures had either disintegrated or were adult in nature whenever a 3rd instar parasitoid was present. It appears, then, that the molt of the parasitoid to its last instar is associated with the host whitefly's nymphal-adult molt. However, the initiation of the host's final molt, while a prerequisite for the parasitoid's 2nd-3rd instar molt, did not necessarily trigger this molt. In contrast to its significant effect on various aspects of parasitoid development, host instar did not significantly influence the mean size of the parasitoid larva, pupa, or adult. Larval and pupal length and adult head width were similar for all parasitoids, regardless of which host instar was parasitized as was adult longevity. Adult parasitoid emergence was

  20. Age-specific interaction between the parasitoid, Encarsia formosa and its host, the silverleaf whitefly, Bemisia tabaci (Strain B

    Directory of Open Access Journals (Sweden)

    Jing S. Hu

    2003-08-01

    Full Text Available The effect of hostage, the instar of Bemisia tabaci (Gennadius parasitized, on the growth and development of Encarsia formosa (Gahan was studied. E. formosa was able to parasitize and complete its life cycle no matter which instar of B. tabaci (Strain B, [also identified as B. argentifolii (Bellows and Perring], was provided for oviposition, but parasitoid development was significantly slower when 1st or 2nd instar B. tabaci rather than 3rd or 4th instars were parasitized. Host age influenced the day on which E. formosa nymphs hatching from eggs was first observed. Mean embryonic development was significantly longer when 1st (5.4 days rather than 2nd, 3rd or 4th instars (4.1, 3.4 and 3.5 days, respectively were parasitized. The duration of the 1st instar parasitoid and the pupa, but not the 2nd or 3rd instar parasitoid, were also significantly greater when 1st instars were parasitized than when older host instars were parasitized. Interestingly, no matter which instar was parasitized, the parasitoid did not molt to the 3rd instar until the 4th instar host had reached a depth of about 0.23 mm (Stage 4-5 and had initiated the nymphal-adult molt and adult development. Histological studies revealed that whitefly eye and wing structures had either disintegrated or were adult in nature whenever a 3rd instar parasitoid was present. It appears, then, that the molt of the parasitoid to its last instar is associated with the host whitefly's nymphal-adult molt. However, the initiation of the host's final molt, while a prerequisite for the parasitoid's 2nd-3rd instar molt, did not necessarily trigger this molt. In contrast to its significant effect on various aspects of parasitoid development, host instar did not significantly influence the mean size of the parasitoid larva, pupa, or adult. Larval and pupal length and adult head width were similar for all parasitoids, regardless of which host instar was parasitized as was adult longevity. Adult parasitoid

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

    Science.gov (United States)

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

    2016-08-01

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

  2. 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...

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

    Science.gov (United States)

    Ferracini, Chiara; Alma, Alberto

    2007-10-01

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

  4. 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.

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

    International Nuclear Information System (INIS)

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

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2013-12-28

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

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

    Science.gov (United States)

    Pant, Shashank; Gera, Tarun; Choudhury, Niharendu

    2013-12-28

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

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

    OpenAIRE

    Magalhães, Sara Henriques de Jesus Paninho

    2009-01-01

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

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

    Science.gov (United States)

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

    2015-12-01

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

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

    Directory of Open Access Journals (Sweden)

    Md. Kalim Uddin

    2015-12-01

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

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

    Science.gov (United States)

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

    2016-06-01

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

  12. 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...

  13. Attention Alters Perceived Attractiveness.

    Science.gov (United States)

    Störmer, Viola S; Alvarez, George A

    2016-04-01

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

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

    OpenAIRE

    Martin D Scoppa; John Peponis

    2015-01-01

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

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

    OpenAIRE

    Fink, Bernhard; Prager, Michael

    2014-01-01

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

  16. Interspecific competition/facilitation among insect parasitoids.

    Science.gov (United States)

    Cusumano, Antonino; Peri, Ezio; Colazza, Stefano

    2016-04-01

    Competition for limited resources is a widespread ecological interaction in animals. In the case of insect parasitoids, species can compete for host resources both at the adult stage as well as at the larval stage. Interspecific competition can play a role in sizing and shaping community structures. In addition of being relevant for basic ecological studies, understanding how interspecific competition between parasitoids affects pest suppression is important for biological control. In this opinion paper we review recent advances in the field of interspecific competition among parasitoids in a biological control perspective. We first discuss adult competition, highlighting which factors are likely to play a role in the outcome of competition when adults interact either directly or indirectly. Then we focus on the interactions occurring between competing larvae that develop within the same host taking also into account the fitness consequences of competition for the larva surviving interspecific competition. We also explore the possibility of interspecific facilitation among parasitoids in those situations in which a given species may benefit from interspecific competition.

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

    CERN Document Server

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

    2014-01-01

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

  18. 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)

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

    NARCIS (Netherlands)

    Stouthamer, R.; Mak, F.

    2002-01-01

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

  20. 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

  1. 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.

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

    Science.gov (United States)

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

  3. 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.

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

    Science.gov (United States)

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

    2008-06-01

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

  5. 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.

  6. Role of virus-like particles in parasitoid-host interaction of insects.

    Science.gov (United States)

    Schmidt, O; Schuchmann-Feddersen, I

    1989-01-01

    Insect endoparasitoids are capable of suppressing the immune reaction of their habitual hosts in a specific way. Salt (1968) characterized some of the implications: This seeming contradiction--that defence reactions against all kinds of foreign bodies are available to insects and that endophagous parasitoids are nevertheless able to develop in insect hosts--is resolved by recourse to one of the principles of host specificity. Although insects as a group react to every foreign body in the sense that any organism or substance evokes a reaction in most insects, each species of insect fails to make a reaction (or makes an ineffective reaction) to a small group of organisms, its habitual parasites. It is the common paradox of parasitology that defence reactions are least effective against the most noxious parasites, involving the tautology that the most noxious parasites are those against which defence reactions are least effective. Recently, VLP of hymenopteran wasps have been shown to play a crucial part in suppressing the cellular encapsulation reaction (Stoltz and Vinson, 1979a). In some parasitoid wasps, polydnavirus particles are involved in the phenotypic transformation of hemocytes, reducing the capability of the host to mount an immune reaction towards the parasitoid egg (Stoltz and Guzo, 1986; Davies et al., 1987). However, at least in Venturia, the eggs are effectively protected by VLP that lack significant amounts of nucleic acids, precluding any virus expression in the host. The question was raised whether VLP could have acquired properties of the host immune system, which allows specific suppression of the immune response. The finding of structural similarities between VLP proteins and a host component indicated that a host function is expressed in VLP (Feddersen et al., 1986) and this observation has subsequently permitted the identification and characterization of a protein in caterpillars, which appears to inhibit cellular defense reactions (Berg et al

  7. 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.

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

    OpenAIRE

    Janczyk, Markus; Heinemann, Alexander; Pfister, Roland

    2012-01-01

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

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

    OpenAIRE

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

    2013-01-01

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

  10. The Effects of Counselor Disability Status and Reputation on Perceptions of Counselor Expertness, Attractiveness, and Trustworthiness.

    Science.gov (United States)

    Leierer, Stephen J.; Strohmer, Douglas C.; Kern, Adrienne M.; Clemons-Guidry, Denise B.; Roberts, Kelly J.; Curry, Karen E.

    1998-01-01

    Adults with disabilities (N=60) viewed videotapes portraying client-counselor reactions to examine the influence of counselor disability status and counselor reputation. A significant effect was found for counselor disability status. Counselors without a disability received higher ratings. There was no effect for reputation, and no interaction was…

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

    Science.gov (United States)

    Duncan-Bazil, Lisa; Foster, Sharon L.

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

  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. PMID:21957136

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

    OpenAIRE

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

    2013-01-01

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

  14. 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.

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

    Science.gov (United States)

    Wuensch, Karl L; Moore, Charles H

    2004-04-01

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

  16. The Moderating Effect of Home Country Corruption on the Host Country’s Ability to Attract FDI

    Directory of Open Access Journals (Sweden)

    Manuel Portugal Ferreira

    2016-01-01

    Full Text Available Prior research has identified a negative impact of corruption on countries’ ability to attract Foreign Direct Investment (FDI but has been scant in assessing the investors’ home country effects. We extend prior research by distinguishing the pervasiveness and arbitrariness of host country corruption and their effects on FDI inflows. We also test whether the investors’ home country corruption affects FDI decisions. Results show that host country pervasive corruption negatively drives FDI inflows but not the arbitrariness component. While the investors’ home country corruption negatively impacts the overall FDI outflows, investors from countries with high levels of corruption do not seem to be deterred by a high level of pervasive corruption in the host country. These results suggest that there may exist some form of corruption-dealing capability whereby firms from countries with high corruption are less sensitive to host country corruption and in fact they are able to leverage their capability and invest more in corrupt hosts.

  17. Physical Attractiveness and Counseling Skills.

    Science.gov (United States)

    Vargas, Alice M.; Borkowski, John G.

    1982-01-01

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

  18. 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.

  19. Interactions between parasitoids and higher order natural enemies

    NARCIS (Netherlands)

    Frago Clols, Enric

    2016-01-01

    Parasitoids kill and live at the expense of their hosts, but they also serve as food for intraguild predators and hyperparasitoids. Natural enemy diversity can thus challenge herbivore suppression by parasitoids, but this depends on the ecological niches of the species involved and their function

  20. Five new associations of parasitoids in potter wasps (Vespidae, Eumeninae

    Directory of Open Access Journals (Sweden)

    Tiago H. Auko

    2014-12-01

    Full Text Available Five new associations of parasitoids in potter wasps (Vespidae, Eumeninae. New associations of host and parasitoids involving potter wasps: Toxophora leucon and Pleurochrysis sp. were found parasitizing Cyphomenes anisitsii, Chrysis sp. (gr. intricans was found parasitizing Minixi suffusum, Plega beardi was found parasitizing Montezumia pelagica sepulchralis and Macrosiagon sp. was found parasitizing Pachodynerus nasidens.

  1. Egg parasitoids of Megamelus spp. (Hemiptera: Delphacidae in Argentina

    Directory of Open Access Journals (Sweden)

    Serguei V. TRIAPITSYN

    2010-01-01

    Full Text Available Se revisaron los parasitoides oófagos (Hymenoptera: Eulophidae, Mymaridae, y Platygastridae de Megamelus spp. (Hemiptera: Delphacidae de la Argentina, y se presenta una clave para su identificación. Se describen cuatro especies nuevas: Anagrus (Anagrus empanadus Triapitsyn, sp. nov. (Mymaridae, parasitoide de M. scutellaris Berg que se alimenta de camalote, Eichhornia crassipes (Martius Solms-Laubach; Aprostocetus (Ootetrastichus riverplaticus Triapitsyn, sp. nov. (Eulophidae: Tetrastichinae, parasitoide de M. bellicus Marino de Remes Lenicov & Sosa; A. (Ootetrastichus yerbamatei Triapitsyn, sp. nov. (parasitoide de M. bellicus, M. scutellaris y Megamelus sp., todos de la provincia de Buenos Aires (A. (Ootetrastichus yerbamatei también se encuentra en Formosa; y Parascelio sabcli Triapitsyn, sp. nov. (Platygastridae: Scelioninae, parasitoide de M. scutellaris en Formosa, la asociación con el huésped es tentativa. Se incluyen otros parasitoides oófagos conocidos de Megamelus spp. en la Argentina, tales como Kalopolynema (Kalopolynema poema Triapitsyn & Berezovskiy (Mymaridae, parasitoide de M. scutellaris en Buenos Aires y también Cremastobaeus atratus Loiácono & Mulvani (Platygastridae: Scelioninae, parasitoide de M. scutellaris en Formosa, la asociación con el huésped es tentativa.

  2. Is parasitoid acceptance of different host species dynamic?

    Science.gov (United States)

    Choice of host individuals by parasitoids is dynamic, varying with physiological state and experience. In particular, female parasitoids with high egg loads and low life expectancy are more willing to accept low quality hosts than females with low egg loads and high life expectancy. However, studi...

  3. 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.

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

    Directory of Open Access Journals (Sweden)

    Stacy Yen-Lin Sim

    2015-12-01

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

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

    CERN Document Server

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

    2015-01-01

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

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

    Science.gov (United States)

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

    2016-06-01

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

  7. The effectiveness of experimental technology of attracting students to physical activity in improving orientation of physical condition

    Directory of Open Access Journals (Sweden)

    Yurchyshyn Y.V.

    2012-09-01

    Full Text Available The effectiveness of designed technologies to attract students during physical education to physical activity improving index is experimentally verified. 174 girls and 171 guys participated in this investigation. Found that the developed technology provides significantly better results than the traditional implementation of the contents of the current program in the following indicators: level of expression at the end of the semester and academic year (the current, final indexes of physical condition, theoretical preparedness in organization and implementation of physical activity improving orientation; number of indexes that in these periods improved, missed days due of sickness, condition, systematic and parameters of motor activity in the student's extracurricular time. These and source control implemented during a special sports and fitness west adversarial method, operational -- at each lesson for assessment of physical activity opportunities to current students.

  8. Hot or Not: The Effects of Exogenous Testosterone on Female Attractiveness to Male Conspecifics in the Budgerigar

    OpenAIRE

    Lahaye, Stefanie E. P.; Marcel Eens; Darras, Veerle M; Rianne Pinxten

    2013-01-01

    An increasing number of studies indicate that not only females but also males can be selective when choosing a mate. In species exhibiting male or mutual mate choice, females may benefit from being attractive. While male attractiveness is often positively influenced by higher plasma levels of the androgenic hormone testosterone, it has been shown that testosterone can masculinise female behavior and morphology in several bird species, potentially rendering them less attractive. In this study,...

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

    OpenAIRE

    Cory, Anna-Lena; Schneider, Jutta M

    2016-01-01

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

  10. Host stage preference and suitability of Allotropa suasaardi Sarkar & Polaszek (Hymenoptera: Platygasteridae, a newly identified parasitoid of pink cassava mealybug, Phenacoccus manihoti (Homoptera: Pseudococcidae

    Directory of Open Access Journals (Sweden)

    Md. Akhtaruzzaman Sarkar

    2015-08-01

    Full Text Available Allotropa suasaardi Sarkar & Polaszek (Hymenoptera: Platygasteridae has been recently reported as a gregarious endoparasitoid of the pink cassava mealybug, Phenacoccus manihoti Matile-Ferrero (Homoptera: Pseudococcidae in Thailand. With the aim of improving mass production of this parasitoid, laboratory experiments were conducted comparing the parasitoid’s preference on different host stages of mealybug, host suitability and its effect on parasitism, development, progeny fitness and sex ratio. All nymphal stages and adult of P. manihoti were parasitized by the parasitoid. However, host stage preference and suitability tests showed that the parasitoid had a significant preference for the older host stages. Percentage parasitization was higher in the third instar and early adult female stages compared with the first and second instar host. Mean developmental time for male parasitoids was shorter than for the females. Higher percentage emergence of parasitoid was observed from older mealybugs. Sex ratios of the offspring produced by the parasitoid were varied in different host stages and the ratio of female to male was higher in the older host stages. The implication of this host selection behavior for mass rearing of A. suasaardi and for evaluating it in a biological control program of the cassava mealybug are discussed.

  11. Host-parasite interactions between whiteflies and their parasitoids.

    Science.gov (United States)

    Gelman, Dale B; Gerling, Dan; Blackburn, Michael B; Hu, Jing S

    2005-12-01

    There is relatively little information available concerning the physiological and biochemical interactions between whiteflies and their parasitoids. In this report, we describe interactions between aphelinid parasitoids and their aleyrodid hosts that we have observed in four host-parasite systems: Bemisia tabaci/Encarsia formosa, Trialeurodes vaporariorum/E. formosa, B. tabaci/Eretmocerus mundus, and T. lauri/Encarsia scapeata. In the absence of reported polydnavirus and teratocytes, these parasitoids probably inject and/or produce compounds that interfere with the host immune response and also manipulate host development to suit their own needs. In addition, parasitoids must coordinate their own development with that of their host. Although eggs are deposited under all four instars of B. tabaci, Eretmocerus larvae only penetrate 4th instar B. tabaci nymphs. A pre-penetrating E. mundus first instar was capable of inducing permanent developmental arrest in its host, and upon penetration stimulated its host to produce a capsule (epidermal in origin) in which the parasitoid larva developed. T. vaporariorum and B. tabaci parasitized by E. formosa initiated adult development, and, on occasion, produced abnormal adult wings and eyes. In these systems, the site of parasitoid oviposition depended on the host species, occurring within or pressing into the ventral ganglion in T. vaporariorum and at various locations in B. tabaci. E. formosa's final larval molt is cued by the initiation of adult development in its host. In the T. lauri-E. scapeata system, both the host whitefly and the female parasitoid diapause during most of the year, i.e., from June until the middle of February (T. lauri) or from May until the end of December (E. scapeata). It appears that the growth and development of the insects are directed by the appearance of new, young foliage on Arbutus andrachne, the host tree. When adult female parasitoids emerged in the spring, they laid unfertilized male

  12. Resource Provisioning as a Habitat Manipulation Tactic to Enhance the Aphid Parasitoid, Aphidius colemani Viereck (Hymenoptera: Braconidae: Aphidiinae), and the Plant-Mediated Effects of a Systemic Insecticide, Imidacloprid

    OpenAIRE

    Charles-Tollerup, Jennifer Jean

    2012-01-01

    Resource provisioning as a habitat manipulation tactic to control the melon aphid, Aphis gossypii, by the polyphagous aphid parasitoid, Aphidius colemani, was investigated in the ornamental, potted-plant nursery using the shrub Photinia x fraseri as a plant host. Floral food resources from an invasive, Conium maculatum, an ornamental, P. x fraseri, and a native, Salvia apiana considerably improved the longevity and fecundity of A. colemani in laboratory experiments. Additionally, floral nec...

  13. 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…

  14. 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…

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

    Science.gov (United States)

    Cory, Anna-Lena; Schneider, Jutta M

    2016-01-01

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

  16. 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.

  17. The role of transient dynamics in biological pest control: insights from a host-parasitoid community.

    Science.gov (United States)

    Kidd, David; Amarasekare, Priyanga

    2012-01-01

    1. Identifying natural enemies that can maintain pests at low abundances is a priority in biological control. Here, we show that experiments combined with models generate new insights into identifying effective control agents prior to their release in the field. Using a host-parasitoid community (the harlequin bug and its egg parasitoids) as a model system, we report three key findings. 2. The interplay between the host's self-limitation and the parasitoids' saturating functional response causes the long-term (steady-state) outcomes for pest suppression to differ from those of short-term (transient) dynamics. When the bug's self-limitation is moderately strong, the parasitoid with the higher attack rate and conversion efficiency (Ooencyrtus) achieves greater host suppression in the long term, but its longer handling time causes long periods of transient dynamics during which the bug can reach high abundances; when the bug's self-limitation is weak, host fluctuations amplify over time and Ooencyrtus fails at host suppression altogether. In contrast, the parasitoid with the lower attack rate and conversion efficiency but the shorter handling time (Trissolcus) induces only weak transient fluctuations of short duration and can maintain the host at low abundances regardless of the strength of the bug's self-limitation. 3. Release of multiple enemy species can compromise host suppression if an enemy that induces stronger transient fluctuations excludes one that induces weaker fluctuations. For instance, Ooencyrtus excludes Trissolcus despite having a longer handling time because of its higher conversion efficiency. The model correctly predicts the time to exclusion observed in experiments, suggesting that it captures the key biological features of the host-parasitoid interaction. 4. Intraspecific interference reduces long-term pest suppression but improves short-term pest control by reducing the magnitude and duration of transient fluctuations. 5. These results highlight

  18. The role of transient dynamics in biological pest control: insights from a host-parasitoid community.

    Science.gov (United States)

    Kidd, David; Amarasekare, Priyanga

    2012-01-01

    1. Identifying natural enemies that can maintain pests at low abundances is a priority in biological control. Here, we show that experiments combined with models generate new insights into identifying effective control agents prior to their release in the field. Using a host-parasitoid community (the harlequin bug and its egg parasitoids) as a model system, we report three key findings. 2. The interplay between the host's self-limitation and the parasitoids' saturating functional response causes the long-term (steady-state) outcomes for pest suppression to differ from those of short-term (transient) dynamics. When the bug's self-limitation is moderately strong, the parasitoid with the higher attack rate and conversion efficiency (Ooencyrtus) achieves greater host suppression in the long term, but its longer handling time causes long periods of transient dynamics during which the bug can reach high abundances; when the bug's self-limitation is weak, host fluctuations amplify over time and Ooencyrtus fails at host suppression altogether. In contrast, the parasitoid with the lower attack rate and conversion efficiency but the shorter handling time (Trissolcus) induces only weak transient fluctuations of short duration and can maintain the host at low abundances regardless of the strength of the bug's self-limitation. 3. Release of multiple enemy species can compromise host suppression if an enemy that induces stronger transient fluctuations excludes one that induces weaker fluctuations. For instance, Ooencyrtus excludes Trissolcus despite having a longer handling time because of its higher conversion efficiency. The model correctly predicts the time to exclusion observed in experiments, suggesting that it captures the key biological features of the host-parasitoid interaction. 4. Intraspecific interference reduces long-term pest suppression but improves short-term pest control by reducing the magnitude and duration of transient fluctuations. 5. These results highlight

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

    OpenAIRE

    Jorlöv, Karin; Venngren, Emma

    2014-01-01

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

  20. Trichogramma parasitoids alter the metabolic physiology of Manduca eggs.

    Science.gov (United States)

    Potter, Kristen A; Woods, H Arthur

    2012-09-01

    Egg parasitoids face unique developmental constraints. First, they have exceptionally limited resources to support themselves and their siblings through three life stages. Second, they develop within the physiological system of another species, which they modify to their own ends. We examined how these constraints affect the metabolic physiology of egg parasitism, and whether parasitoids retool their host eggshell to account for their different metabolic demands. Higher-conductance eggshells allow more oxygen to reach the developing parasitoids, but also allow more water to leave the egg. We used Manduca sexta (Lepidoptera: Sphingidae) eggs and Trichogramma (Hymenoptera: Trichogrammatidae) parasitoids from southeastern AZ, USA. Compared with unparasitized Manduca eggs, eggs parasitized by Trichogramma had lower peak metabolic rates and approximately 50 per cent lower metabolic efficiency. However, developing Trichogramma were far more efficient than typical transfer efficiencies between tropic levels (approx. 10%). Even within a few hours of parasitization, eggs containing more Trichogramma had lower per-parasitoid metabolic rates, suggesting that parasitoid larvae have mechanisms for rapidly adjusting their metabolic rates based on number of siblings. Parasitoids also appear to control the conductance of their host eggshell: their different metabolic demands were mirrored by shifts in rates of water loss. PMID:22719035

  1. Biological Control of Solenopsis Fire Ants by Pseudacteon Parasitoids: Theory and Practice

    OpenAIRE

    Morrison, Lloyd W.

    2012-01-01

    Pseudacteon parasitoids are potential biocontrol agents of invasive Solenopsis fire ants. Pseudacteon species that parasitize the invasive S. invicta Buren and S. richteri Forel have been introduced to, and naturally dispersed across, the southeastern USA, although there is no evidence yet that Solenopsis host ant populations have decreased. The ability of introduced Pseudacteon species to regulate Solenopsis populations will depend upon the relative importance of top-down effects in the reci...

  2. The role of geography and host abundance in the distribution of parasitoids of an alien pest

    OpenAIRE

    Nováková, Petra; Holuša, Jaroslav; Horák, Jakub

    2016-01-01

    Chalcid wasps (Hymenoptera: Chalcidoidea) are probably the most effective and abundant parasitoids of the horse chestnut leaf miner (Cameraria ohridella), an alien pest in Europe that lacks specialized enemies. We studied how the species richness and abundance of chalcids are influenced by altitude, direction of an alien spread and host abundance of C. ohridella. We quantified the numbers and species richness of chalcid wasps and the numbers of C. ohridella that emerged from horse chestnut (A...

  3. Herbivore-induced volatile emission in black poplar: regulation and role in attracting herbivore enemies.

    Science.gov (United States)

    Clavijo McCormick, Andrea; Irmisch, Sandra; Reinecke, Andreas; Boeckler, G Andreas; Veit, Daniel; Reichelt, Michael; Hansson, Bill S; Gershenzon, Jonathan; Köllner, Tobias G; Unsicker, Sybille B

    2014-08-01

    After herbivory, plants release volatile organic compounds from damaged foliage as well as from nearby undamaged leaves that attract herbivore enemies. Little is known about what controls the volatile emission differences between damaged and undamaged tissues and how these affect the orientation of herbivore enemies. We investigated volatile emission from damaged and adjacent undamaged foliage of black poplar (Populus nigra) after herbivory by gypsy moth (Lymantria dispar) caterpillars and determined the compounds mediating the attraction of the gypsy moth parasitoid Glyptapanteles liparidis (Braconidae). Female parasitoids were more attracted to gypsy moth-damaged leaves than to adjacent non-damaged leaves. The most characteristic volatiles of damaged versus neighbouring undamaged leaves included terpenes, green leaf volatiles and nitrogen-containing compounds, such as aldoximes and nitriles. Electrophysiological recordings and olfactometer bioassays demonstrated the importance of nitrogenous volatiles. Under field conditions, parasitic Hymenoptera were more attracted to traps baited with these substances than most other compounds. The differences in volatile emission profiles between damaged and undamaged foliage appear to be regulated by jasmonate signalling and the local activation of volatile biosynthesis. We conclude that characteristic volatiles from damaged black poplar foliage are essential cues enabling parasitoids to find their hosts.

  4. Study on the parasitoids of Pissodes nitidus Roel.

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    A systematic observation and intensive study on the parasitoids of Pissodes nitidus were made in Langxiang and Xin'qing Forestry Bureau in Xiaoing'an Mountain area in 1996-1999, including the diagnosis, life history, biological characteristics of Eurytoma sp. and parasitoid complex of Pissodes nitidus. There were about 70 species of parasitoids on Pissodes nitidus, including Eurytomidae, Ichneumonidae and Braconidae etc. Among them, Eurytoma sp. is a dominant species and a braconid, Ipobracon sp. is a subdominant species, and they play an important role in controlling the pest.

  5. Impact of change in winter strategy of one parasitoid species on the diversity and function of a guild of parasitoids.

    Science.gov (United States)

    Andrade, Thiago Oliveira; Krespi, Liliane; Bonnardot, Valérie; van Baaren, Joan; Outreman, Yannick

    2016-03-01

    The rise of temperatures may enable species to increase their activities during winter periods and to occupy new areas. In winter, resource density is low for most species and an increased number of active consumers during this season may produce heightened competitive pressure. In Western France, the aphid parasitoid species Aphidius avenae Haliday has been known to adopt a winter diapausing strategy adjacent to newly sown cereal crops, until recent reports of active winter populations in cereal crops. We investigate how the addition of this species to the winter guild of parasitoids may change the structure of the aphid-parasitoid food web and the host-exploitation strategies of previously occurring parasitoids. We showed that in winter, Aphidius avenae was mostly associated with two aphid species, Sitobion avenae Fabricius and Metopolophium dirhodum Walker, while the generalist species Aphidius rhopalosiphi was restricted to the aphid species Rhopalosiphum padi L. in the presence of Aphidius avenae. Due to this new competition, winter food webs present a higher degree of compartmentalization and lower proportional similarity index values than spring ones. Parasitoid and aphid abundances responded significantly to changes in daily high temperatures, suggesting that the host-parasitoid community structure can be partly predicted by climate. This study demonstrates how a change in the winter strategy of one species of a guild can modify complex interspecific relationships in host-parasitoid systems.

  6. The Parasitoid Factor in the Virulence and Spread of Lepidopteran Baculoviruses

    Institute of Scientific and Technical Information of China (English)

    J. E. Cossentine

    2009-01-01

    Insect parasitoids and baculoviruses play important roles in the natural and strategic biological control of insects. The two parasites are frequent competitors within common hosts and much research has focused on the negative impact that baculoviral host infections have on parasitoids. This review summarizes the impacts that parasitoids may have on the virulence and spread of lepidopteran baculoviruses. By changing host behavior and development, parasitoids have been shown to decrease baculovirus virulence and productivity within parasitized baculovirus-susceptible hosts; however, studies of the tools used by hymenopteran parasitoids to overcome their hosts' immune systems, suggest that parasitoids may, in some cases, facilitate baculoviral infections in less susceptible hosts. Laboratory and field research have demonstrated that parasitoids can mechanically transmit bacuioviruses between insects, and in this way, increase the efficacy of the viruses. Instances of new, more virulent isolates of baculoviruses have been recorded from specifically parasitoid-targeted hosts suggesting other possible benefits from the transmission or activation of baculoviruses by parasitoids.

  7. 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.

  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 individua

  9. 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 individual

  10. Allomonal effect of breath contributes to differential attractiveness of humans to the African malaria vector Anopheles gambiae

    NARCIS (Netherlands)

    Mukabana, W.R.; Takken, W.; Killeen, G.F.; Knols, B.G.J.

    2004-01-01

    Background - Removal of exhaled air from total body emanations or artificially standardising carbon dioxide (CO2) outputs has previously been shown to eliminate differential attractiveness of humans to certain blackfly (Simuliidae) and mosquito (Culicidae) species. Whether or not breath contributes

  11. 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

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

    Institute of Scientific and Technical Information of China (English)

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

    2015-01-01

    (E)-b-Farnesene (EbF) synthase catalyses the production of EbF, 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 EbF synthase genes and can release EbF to repel aphids. In order to effectively recruit the plant-derived EbF 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 AabFS1, an EbF synthase gene from sweet wormwood (Artemisia annua L.), to the chloroplast of tobacco to generate CTP þ AabFS1 transgenic lines. The CTP þ AabFS1 transgenic tobacco plants could emit EbF at a level up to 19.25 ng/day per g fresh tissues, 4–12 fold higher than the AabFS1 transgenic lines without chloroplast targeting. Furthermore, aphid/parasitoid behavioral bio-assays demonstrated that the CTP þ AabFS1 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 EbF synthase genes to generate a novel type of transgenic plant emitting an alarm pheromone for aphid control.

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

    OpenAIRE

    Qingguo eMa; Yue eHu; Shushu eJiang; Liang eMeng

    2015-01-01

    To investigate the time course of the neural processing of facial attractiveness and its influence on fairness consideration during social interactions, event-related potentials (ERP) were recorded from 21 male subjects performing a two-person Ultimatum Game (UG). During this bargaining game, the male subjects played responders who decided whether to accept offers from female proposers, whose facial images (grouped as attractive and unattractive) were presented prior to the offer presentation...

  14. Ethnic and gender consensus for the effect of waist-to-hip ratio on judgment of women's attractiveness.

    Science.gov (United States)

    Singh, D; Luis, S

    1995-03-01

    The western consensus is that obese women are considered attractive by Afro-Americans and by many societies from nonwestern developing countries. This belief rests mainly on results of nonstandardized surveys dealing only with body weight and size, ignoring body fat distribution. The anatomical distribution of female body fat as measured by the ratio of waist to hip circumference (WHR) is related to reproductive age, fertility, and risk for various major diseases and thus might play a role in judgment of attractiveness. Previous research (Singh 1993a, 1993b) has shown that in the United States Caucasian men and women judge female figures with feminine WHRs as attractive and healthy. To investigate whether young Indonesian and Afro-American men and women rate such figures similarly, female figures representing three body sizes (underweight, normal weight, and overweight) and four WHRs (two feminine and two masculine) were used. Results show that neither Indonesian nor Afro-American subjects judge overweight figures as attractive and healthy regardless of the size of WHR. They judged normal weight figures with feminine WHRs as most attractive, healthy, and youthful. The consensus on women's attractiveness among Indonesian, Afro-American, and U.S. Caucasian male and female subjects suggests that various cultural groups have similar criteria for judging the ideal woman's shape. PMID:24202830

  15. Web-based recruitment: effects of information, organizational brand, and attitudes toward a Web site on applicant attraction.

    Science.gov (United States)

    Allen, David G; Mahto, Raj V; Otondo, Robert F

    2007-11-01

    Recruitment theory and research show that objective characteristics, subjective considerations, and critical contact send signals to prospective applicants about the organization and available opportunities. In the generating applicants phase of recruitment, critical contact may consist largely of interactions with recruitment sources (e.g., newspaper ads, job fairs, organization Web sites); however, research has yet to fully address how all 3 types of signaling mechanisms influence early job pursuit decisions in the context of organizational recruitment Web sites. Results based on data from 814 student participants searching actual organization Web sites support and extend signaling and brand equity theories by showing that job information (directly) and organization information (indirectly) are related to intentions to pursue employment when a priori perceptions of image are controlled. A priori organization image is related to pursuit intentions when subsequent information search is controlled, but organization familiarity is not, and attitudes about a recruitment source also influence attraction and partially mediate the effects of organization information. Theoretical and practical implications for recruitment are discussed. PMID:18020806

  16. 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.

  17. Impact of insecticides on parasitoids of the leafminer, Liriomyza trifolii, in pepper in south Texas.

    Science.gov (United States)

    Hernández, Ricardo; Harris, Marvin; Liu, Tong-Xian

    2011-01-01

    Liriomyza leafminers (Diptera: Agromyzidae) are cosmopolitan, polyphagous pests of horticultural plants and many are resistant to insecticides. Producers in South Texas rely on insecticides as the primary management tool for leafminers, and several compounds are available. The objective of this study is to address the efficacy of these compounds for controlling Liriomyza while minimizing their effects against natural enemies. Research plots were established at Texas AgriLife research center at Weslaco, Texas in fall 2007 and spring 2008 seasons, and peppers were used as a model crop. Plots were sprayed with novaluron, abamectin, spinetoram, lambda-cyhalothrin and water as treatments according to leafminer infestation; insecticide efficacy was monitored by collecting leaves and infested foliage. Plant phenology was also monitored. Novaluron was the most effective insecticide and lambda-cyhalothrin showed resurgence in leafminer density in fall 2007 and no reduction in spring 2008. Other compounds varied in efficacy. Novaluron showed the least number of parasitoids per leafminer larva and the lowest parasitoid diversity index among treatments followed by spinetoram. Liriomyza trifolii (Burgess) was the sole leafminer species on peppers, and 19 parasitoid species were found associated with this leafminer. Application of these insecticides for management of leafminers with conservation of natural enemies is discussed. PMID:21864155

  18. New traps for capturing Pseudacteon phorid flies, parasitoids of red imported fire ant Solenopsis invicta Buren%寄生红火蚁的蚤蝇类群野外监测新技术

    Institute of Scientific and Technical Information of China (English)

    陆永跃; Sanford D.Porter; 曾玲

    2011-01-01

    通过试验研究,设计出了3个适于监测、收集红火蚁Solenopsis invicta Buren天敌-蚤蝇Pseudacteon的诱集器,并提出了该诱集器的制作和野外设置的技术要求.测试了野外该诱集器对蚤蝇的监测、收集效果,证实该装置是可行的和实用的.%Three new types of traps for capturing the Pseudacteon phorid flies, parasitoids of red imported fire ant Solenopsis invicta Buren, in fields were designed after experiments and tests in this paper. The technical points of trap construction and set were presented. The traps were proved to be attractive and effective after they were evaluated in capturing Pseudacteon phorid flies in fields.

  19. 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

  20. What Is the Relationship between the Age of the Audience and the Effectiveness of Marketing Techniques in Attracting Students to a Community College?

    Science.gov (United States)

    Silberg, Carol A.

    A study was conducted at Prince George's Community College (PGCC) to investigate the relationship between the age of the audience and the effectiveness of marketing techniques in attracting students to the college. The study focused on how and why community colleges market themselves, and why some techniques were more effective than others for…

  1. Euclidean gravity attracts

    OpenAIRE

    Bakker MR; Smit, J.

    1993-01-01

    We look at gravitational attraction in simplicial gravity using the dynamical triangulation method. On the dynamical triangulation configurations we measure quenched propagators of a free massive scalar field. The masses measured from these propagators show that gravitational attraction is present.

  2. Euclidean gravity attracts

    CERN Document Server

    De Bakker, B V; Bakker, Bas de; Smit, Jan

    1994-01-01

    We look at gravitational attraction in simplicial gravity using the dynamical triangulation method. On the dynamical triangulation configurations we measure quenched propagators of a free massive scalar field. The masses measured from these propagators show that gravitational attraction is present.

  3. Packing of Fruit Fly Parasitoids for Augmentative Releases

    OpenAIRE

    Pablo Montoya; Lía Ruiz; Jorge Cancino

    2012-01-01

    The successful application of Augmentative Biological Control (ABC) to control pest fruit flies (Diptera: Tephritidae) confronts two fundamental requirements: (1) the establishment of efficient mass rearing procedures for the species to be released, and (2) the development of methodologies for the packing and release of parasitoids that permit a uniform distribution and their optimal field performance under an area-wide approach. Parasitoid distributions have been performed by ground and by a...

  4. Trichogramma parasitoids alter the metabolic physiology of Manduca eggs

    OpenAIRE

    Potter, Kristen A.; Woods, H. Arthur

    2012-01-01

    Egg parasitoids face unique developmental constraints. First, they have exceptionally limited resources to support themselves and their siblings through three life stages. Second, they develop within the physiological system of another species, which they modify to their own ends. We examined how these constraints affect the metabolic physiology of egg parasitism, and whether parasitoids retool their host eggshell to account for their different metabolic demands. Higher-conductance eggshells ...

  5. Advances and perspectives in the mass rearing of fruit fly parasitoids in Mexico

    International Nuclear Information System (INIS)

    Biological control by augmentation is applied in Mexico as part of an integrated pest management program against native fruit flies of the genus Anastrepha Schiner. The exotic parasitoid Diachasmimorpha longicaudata has been the most important species used within this context. A program for the mass rearing of 50 million parasitized pupa per week has been established in southeast Mexico, and these are released into the field according to a yearly national plan based on industry requirements. In order to reduce costs and optimize procedures, important advances have been made in the technology for mass production, including an increase in the weight of host larvae (24 mg), changes in the management of host exposition, improvements in the management of environmental conditions, suitability in time and motions are the main areas addressed. Furthermore, a quality control program is routinely applied, and the key parameters under constant evaluation are: 1) weight and volume of host larvae, 2) host mortality after exposure, 3) weight and volume of pupae, and 4) percent parasitoid viability and percent emergence. Good performance in these parameters produces adults with adequate longevity and fecundity, high flight ability and good searching behavior. The introduced egg parasitoid Fopius arisanus and the native pupal parasitoid Coptera hawardi are being evaluated for use in the future as a complement to releases into the field of D. longicaudata. Manipulating host size and exposition time, the use of starting diet and suppressing host development by irradiation, have permitted the effective use of Anastrepha eggs as hosts for the rearing of F. arisanus. Further achievements in the mass rearing of C. haywardi (e.g., the suppression of unparasitized hosts after irradiation), could give us the opportunity to employ new options to reinforce the augmentative biological control of Anastrepha fruit flies in Mexico. (author)

  6. 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)

  7. The effect of resource provisioning and sugar composition of foods on longevity of three Gonatocerus spp., egg parasitoids of Homalodisca vitripennis

    Science.gov (United States)

    The effect of dietary supplements on the longevity of male and female Gonatocerus ashmeadi, G. triguttatus and G. fasciatus (Hymenoptera: Mymaridae), was determined in the laboratory. Treatments included: water only, 3:1 honey–water solution, floral and extra-floral nectars from five different plant...

  8. 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.

  9. Dead ant walking: a myrmecophilous beetle predator uses parasitoid host location cues to selectively prey on parasitized ants.

    Science.gov (United States)

    Mathis, Kaitlyn A; Tsutsui, Neil D

    2016-08-17

    Myrmecophiles (i.e. organisms that associate with ants) use a variety of ecological niches and employ different strategies to survive encounters with ants. Because ants are typically excellent defenders, myrmecophiles may choose moments of weakness to take advantage of their ant associates. This hypothesis was studied in the rove beetle, Myrmedonota xipe, which associates with Azteca sericeasur ants in the presence of parasitoid flies. A combination of laboratory and field experiments show that M. xipe beetles selectively locate and prey upon parasitized ants. These parasitized ants are less aggressive towards beetles than healthy ants, allowing beetles to eat the parasitized ants alive without interruption. Moreover, behavioural assays and chemical analysis reveal that M. xipe are attracted to the ant's alarm pheromone, the same secretion used by the phorid fly parasitoids in host location. This strategy allows beetles access to an abundant but otherwise inaccessible resource, as A. sericeasur ants are typically highly aggressive. These results are the first, to our knowledge, to demonstrate a predator sharing cues with a parasitoid to gain access to an otherwise unavailable prey item. Furthermore, this work highlights the importance of studying ant-myrmecophile interactions beyond just their pairwise context. PMID:27512148

  10. 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.

  11. 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. PMID:25062930

  12. Interpersonal Congruency, Attitude Similarity, and Interpersonal Attraction

    Science.gov (United States)

    Touhey, John C.

    1975-01-01

    As no experimental study has examined the effects of congruency on attraction, the present investigation orthogonally varied attitude similarity and interpersonal congruency in order to compare the two independent variables as determinants of interpersonal attraction. (Author/RK)

  13. Effect of trap color and orientation on the capture of Aphelinus mali (Hymenoptera: Aphelinidae), a parasitoid of woolly apple aphid (Hemiptera: Aphididae).

    Science.gov (United States)

    Beers, Elizabeth H

    2012-08-01

    The factors affecting trap capture of adult Aphelinus mali (Haldeman) (Hymenoptera: Aphelinidae) were studied in 2010-2011 in eastern Washington apple (Malus spp.) orchards infested with its host woolly apple aphid, Eriosoma lanigerum (Hausmann) (Hemiptera: Aphididae). The initial study of white sticky cards indicated that traps stapled to the trunk in a vertical orientation had the highest capture. A factorial experiment of three colors (clear, white, and yellow) by three orientations (trunk, scaffold, and hanging) indicated that yellow traps and traps on trunks caught higher numbers ofA. mali. For this reason, the recommended trap for this natural enemy is a yellow trap stapled to the trunk. Having a readily available and effective sampling method for this species may be helpful in implementing biological control programs and assessing the impact of different spray regimes. PMID:22928315

  14. Developmental time, longevity, and lifetime fertility of three introduced parasitoids of the mealybug Paracoccus marginatus (Hemiptera: Pseudococcidae).

    Science.gov (United States)

    Amarasekare, Kaushalya G; Mannion, Catharine M; Epsky, Nancy D

    2012-10-01

    Developmental time, longevity, and lifetime fertility of three previously introduced parasitoids (Acerophagus papayae Noyes and Schauff, Anagyrus loecki Noyes and Menezes, and Pseudleptomastix mexicana Noyes and Schauff) (Hymenoptera: Encyrtidae) of the mealybug Paracoccus marginatus Williams and Granara de Willink (Hemiptera: Pseudococcidae) were studied in the laboratory to understand the outcome of their recovery in field studies conducted in the United States. The developmental time of both male and female A. papayae and A. loecki was shorter than the developmental time of male and female P. mexicana. Male parasitoids of all three species had a shorter developmental time than their females. All parasitoids had a shorter developmental time in adult-female mealybugs than in second instars. Mating status (unmated and mated) had no effect on the male longevity. Unmated and mated females that were not allowed to oviposit had similar longevity and lived longer than those that were allowed to oviposit. Virgin females produced male only progeny with higher number of males from A. loecki or P. mexicana than from A. papayae. The number of females and the cumulative progeny was smaller for A. papayae than for A. loecki or P. mexicana. The progeny sex ratio (proportion of females) was not different among the parasitoids. A. papayae had the shortest reproductive period followed by A. loecki and P. mexicana, respectively. This information is important in evaluating the efficiency, recovery and establishment of A. papayae, A. loecki, and P. mexicana.

  15. Age at reproductive maturity and effect of age and time of day on sex attraction in the potato psyllid Bactericera cockerelli

    Institute of Scientific and Technical Information of China (English)

    Christelle Guédot; David R.Horton; Peter J.Landolt

    2012-01-01

    The potato psyllid,Bactericera (=Paratrioza) cockerelli ((S)ulc) (Hemiptera:Triozidae),is a major pest of potato.Studies were conducted to determine the age at which both males and females reach reproductive maturity and the effect of age and time of day on sex attraction.Adult B.cockerelli reach reproductive maturity within 48 h post-eclosion,with females being mature on the day of eclosion and males at 1 day post-eclosion.Oviposition generally began 2 days after mating but was delayed when females mated within 2 days post-eclosion.In laboratory olfactometer assays,the age of females used as odor sources and the age of males assayed to these odors did not affect sex attraction,with both younger (1-4-day-old) and older (8-10-day-old) males being attracted to females,regardless of female age (1-4-day-old or 8-10-day-old).Males assayed to live females at different times during the photophase (between 8:00 and 20:00 hours) were attracted to females between 11:00 and 17:00 hours,showing a temporal periodicity in sex attraction with B.cockerelli at least during the photophase.

  16. Chemosignalling effects of human tears revisited : Does exposure to female tears decrease males' perception of female sexual attractiveness?

    NARCIS (Netherlands)

    Gracanin, A.; van Assen, M.A.L.M.; Omrčen, Višnja; Koraj, Ivana; Vingerhoets, A.J.J.M.

    2016-01-01

    Gelstein et al. reported the results of three experiments suggesting a dampening influence of inhalation of female emotional tears on males' arousal and perception of female sexual attractiveness, specifically in non-sexual situations. This prompted the hypothesis that crying exerts its influence on

  17. Differential attractiveness of humans to the African malaria vector Anopheles gambiae Giles - Effects of host characteristics and parasite infection

    NARCIS (Netherlands)

    Mukabana, W.R.

    2002-01-01

    The results of a series of studies designed to understand the principal factors that determine the differential attractiveness of humans to the malaria vector Anopheles gambiae are described in this thesis. Specific

  18. 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…

  19. Functional and evolutionary insights from the genomes of three parasitoid Nasonia species

    DEFF Research Database (Denmark)

    Werren, John H; Richards, Stephen; Desjardins, Christopher A;

    2010-01-01

    We report here genome sequences and comparative analyses of three closely related parasitoid wasps: Nasonia vitripennis, N. giraulti, and N. longicornis. Parasitoids are important regulators of arthropod populations, including major agricultural pests and disease vectors, and Nasonia is an emergi...

  20. 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

  1. Host preference of the egg parasitoids Telenomus remus and Trichogramma pretiosum in laboratory

    OpenAIRE

    Maria Mirmes Paiva Goulart; Adeney de Freitas Bueno; Regiane Cristina Oliveira de Freitas Bueno; Adenil Ferreira Diniz

    2011-01-01

    Host preference of the egg parasitoids Telenomus remus and Trichogramma pretiosum in laboratory. This research aimed to evaluate the host preference of the egg parasitoids Telenomus remus and Trichogramma pretiosum. Trials were carried out in laboratory, under controlled environmental conditions (25 ± 2ºC temperature; 70 ± 10% RH; and 14 h photophase). The parasitoid searching behavior was evaluated based on the distribution (%) of eggs parasitized by each parasitoid, on egg masses of each ho...

  2. Attraction of the housefly (Musca domestica L)

    NARCIS (Netherlands)

    Smallegange, RC; den Otter, CJ; Sommeijer, MJ; Francke, PJ

    1998-01-01

    Ultraviolet (UV) light attracts more houseflies compared to green and white light. The attractiveness of UV light is not effected by its spectral composition. The number of flies attracted does not seem to change when a UV lamp is combined with moving elements, although the time spend on the lamp de

  3. Gut sugar analysis in field-caught parasitoids: adapting methods originally developed for biting flies

    NARCIS (Netherlands)

    Heimpel, G.E.; Lee, J.E.; Wu, Z.; Weiser, L.; Wäckers, F.L.; Jervis, M.A.

    2004-01-01

    The ability to determine the presence and identity of sugars in the guts of adult parasitoids in the field would aid researchers in addressing long-standing problems in parasitoid ecology. Until very recently, however, gut sugar analyses have not been carried out on parasitoids. This is despite the

  4. 旅游景区形象对顾客忠诚的影响研究%The Effects of Tourist Attractions Image on Customer Loyalty

    Institute of Scientific and Technical Information of China (English)

    邱宏亮; 吴雪飞; 钱正英

    2012-01-01

    Combined the review of related literature with the qualitative research, the four-dimension measurement model of tourist attractions image is proposed. And the structural model of each dimension of tourist attractions image affecting relationship among value, satisfaction and loyalty is constructed. Empirical results indicate that: (1)the measurement model of tourist attractions image which includes landscape and health, tourist attractions price, tourist attractions service, infrastructure has been ac- ceptable levels of reliability, overall fit, convergent validity, discriminant validity; (Z)Each dimension of tourist attractions image has different effects on the customer's value-satisfaction-loyalty.%采用文献回顾和定性研究相结合的方法,提出了旅游景区形象4维度测量模型。基于此,建立了旅游景区形象各维度对顾客忠诚的作用机制模型.数据研究表明:(1)笔者开发的旅游景区形象量表具有较好的信度水平、整体拟合优度、收敛效度、判别效度,它包括风景与卫生、景区价格、景区服务、基础设施等4个结构维度;(2)旅游景区形象各维度对顾客忠诚存在不同的作用机理与影响效应.

  5. [Effect of different baits as attractant for blowflies (Diptera) at Valonguinho, Universidade Federal Fluminense, Niterói, RJ, Brazil].

    Science.gov (United States)

    d'Almeida, José M; Fraga, Mariana B

    2007-01-01

    It was carried out a survey of blowflies in an area of the Campus (Valonguinho) of the Universidade Federal Fluminense, Niterói, Rio de Janeiro. The collections were performed with traps, using baits of fish (sardine), bovine liver, shrimps and banana. Were collected 6015 flies, Chrysomya megacephala and Lucilia eximia were the most frequent (50.55% and 21.52%, respectively). The flies were more abundant in February and March and the most attractive bait was fish (38.32%).

  6. The Effect of Cues of Parental Investment on Attractiveness Ratings of Males: The Impact of Child Presence and Age

    OpenAIRE

    Went, Hannah

    2007-01-01

    According to evolutionary theories of mate choice, male parental investment is a desired characteristic of long term mates. Brase (2006) found that cues of a positive disposition towards parental investment increased males’ perceived attractiveness to females. Interacting with a child was taken to be a measure of males’ disposition towards parental investment. The present study sought to replicate and extend these findings by altering the age of the child involved. The results ...

  7. Molecular Weight Dependence of the Depletion Attraction and its Effects on the Competitive Adsorption of Lung Surfactant

    OpenAIRE

    Stenger, Patrick C.; Isbell, Stephen G.; Zasadzinski, Joseph A.

    2008-01-01

    Albumin competes with lung surfactant for the air-water interface, resulting in increased surface tension. Polyethylene glycol (PEG) and other hydrophilic polymers restore the normal rate of surfactant adsorption to the interface, which re-establishes low surface tensions on compression. PEG does so by generating an entropic depletion attraction between the surfactant aggregates and interface, reducing the energy barrier to adsorption imposed by the albumin. For a fixed composition of 10 g/L ...

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

    OpenAIRE

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

    2015-01-01

    To investigate the time course of the neural processing of facial attractiveness and its influence on fairness consideration during social interactions, event-related potentials (ERP) were recorded from 21 male subjects performing a two-person Ultimatum Game (UG). During this bargaining game, the male subjects played responders who decided whether to accept offers from female proposers, whose facial images (grouped as “attractive” and “unattractive”) were presented prior to the offer presenta...

  9. 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.

  10. 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.

  11. Host specialisation and competition asymmetry in coleopteran parasitoids.

    Science.gov (United States)

    Bili, Mikaël; Cortesero, A M; Outreman, Y; Poinsot, D

    2016-09-01

    When specialists and generalists compete for a limited resource, specialists are more constrained because they are less likely to find an alternative resource. In parasitoids with overlapping host ranges, asymmetric competition should therefore exist where specialists are more likely to win the host in a contest. Competition between parasitoids has been studied mostly in hymenopterans. In hymenopteran parasitoid wasps, females must reach the host to lay their eggs and can thus strongly influence the outcome of competition between future offspring by killing eggs or larvae of competitors. We studied competition between the free-ranging larvae of two sympatric coleopteran parasitoid rove beetles (one specialist, Aleochara bilineata and a generalist, Aleochara bipustulata) with overlapping host ranges competing in agricultural fields for pupae of the cabbage root fly. In these species, females lay their eggs in the soil, then first instars find the host where they will develop as solitary parasitoids and deal with potential competitors. Because adult longevity and fecundity favour the generalist, we postulated that first instars of the specialist would be superior larval competitors. Accordingly, we studied the outcome of encounters between first instars of the two species provided with a single host. Irrespective of its release prior to or simultaneously with its generalist competitor, the larva of the specialist most often won. Moreover, specialist larvae still won half of the encounters when generalist larvae were given a 24-h advantage. This might explain the coexistence of the two species in the field.

  12. Location of Host and Host Habitat by Fruit Fly Parasitoids

    Directory of Open Access Journals (Sweden)

    Pascal Rousse

    2012-11-01

    Full Text Available Augmentative releases of parasitoids may be a useful tool for the area-wide management of tephritid pests. The latter are parasitized by many wasp species, though only a few of them are relevant for augmentative biocontrol purposes. To date, nearly all the actual or potential biocontrol agents for such programs are egg or larval Opiinae parasitoids (Hymenoptera: Braconidae. Here, we review the literature published on their habitat and host location behavior, as well as the factors that modulate this behavior, which is assumed to be sequential; parasitoids forage first for the host habitat and then for the host itself. Parasitoids rely on chemical, visual, and mechanical stimuli, often strongly related to their ecology. Behavioral modulation factors include biotic and abiotic factors including learning, climatic conditions and physiological state of the insect. Finally, conclusions and perspectives for future research are briefly highlighted. A detailed knowledge of this behavior may be very useful for selecting the release sites for both inundative/augmentative releases of mass-reared parasitoids and inoculative releases for classical biocontrol.

  13. 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…

  14. Assertiveness and Physical Attractiveness.

    Science.gov (United States)

    Kleim, David M.; And Others

    Earlier research investigating the relationship between physical attractiveness and assertiveness found that physically attractive females were more assertive than other females. To investigate this relationship further and to broaden the scope of the study, 69 students were videotaped in groups of five to ten while responding to open-ended…

  15. The effect of public Polices on the attractiveness of emerging countries for the development of innovation activities by multinational firms

    Directory of Open Access Journals (Sweden)

    Eva Stal

    2009-03-01

    Full Text Available Multinational firms contribute to the development of innovative capacity in countries where they establish subsidiaries and research centers. However, they still conduct most of their R&D at home or in developed countries’ based subsidiaries. The resources offered by the host country affect the level of local R&D, and they constitute what Dunning calls the L (location variable of his Eclectic Paradigm of International Production. It includes a big domestic market, availability of qualified and low-cost professionals, technological (universities and research institutes and communication infrastructure, protection of intellectual property rights, commercial policies and the scale of the national technological effort. These aspects define the type and scope of R&D that will be done locally. The article aims at showing that emerging countries need a strong action from the government, in order to improve their attractiveness to MNCs. The Brazilian Informatics Act is an example of a successful policy, which attracted many foreign companies, in exchange of tax incentives and the requirement of local R&D activities. The results are based on interviews with a group of firms established in the Campinas region.

  16. 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

    -product pests and their biological control. Results 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......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...

  17. 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.

  18. Body sizes of hosts and parasitoids in individual feeding relationships

    OpenAIRE

    Joel E. Cohen; Jonsson, Tomas; Müller, Christine B.; Godfray, H. C. J.; Savage, M

    2005-01-01

    In a natural community of 49 species (12 species of aphids and 37 species of their parasitoids), body lengths of 2,151 parasitoid individuals were, to an excellent approximation, related to the body lengths of their individual aphid hosts by a power law with an exponent close to 3/4. Two alternative models predict this exponent. One is based on surface area to volume relationships. The other is based on recent developments in metabolic ecology. Both models require a changing ratio (in both ho...

  19. Comparison of Host-Seeking Behavior of the Filth Fly Pupal Parasitoids, Spalangia cameroni and Muscidifurax raptor (Hymenoptera: Pteromalidae).

    Science.gov (United States)

    Machtinger, E T; Geden, C J; Teal, P E; Leppla, N C

    2015-04-01

    The pupal parasitoids, Spalangia cameroni Perkins and Muscidifurax raptor Girault and Sanders, can be purchased for biological control of house flies Musca domestica L. and stable flies Stomoxys calcitrans (L.) (Diptera: Muscidae). Little is known about the odors involved in host-seeking behavior of these two species, so odors associated with house flies were investigated in the laboratory using a Y-tube olfactometer. Odor stimuli from house fly host puparia, larvae, pine-shavings bedding with horse manure, and developing flies in the pine-shavings-manure substrate were evaluated in bioassays using the two pteromalid species. In choice tests, naïve female S. cameroni were strongly attracted to odor from the substrate containing house fly larvae and secondarily from the uninfested substrate and substrate with puparia versus humidified and purified air. This species also selected the substrate with larvae versus the substrate with the house fly puparia or uninfested substrate. Muscidifurax raptor was attracted to odor from the substrate containing puparia, washed puparia, and substrate with puparia removed. The data suggest that coexistence between the two pteromalid parasitoids, S. cameroni and M. raptor, might be promoted by different host-seeking behavior.

  20. Biotic and abiotic factors affecting the flight activity of Fopius arisanus, an egg-pupal parasitoid of fruit fly pests.

    Science.gov (United States)

    Rousse, P; Gourdon, F; Roubaud, M; Chiroleu, F; Quilici, S

    2009-06-01

    Climatic conditions and the physiological state of a parasitoid may alter its host selection behavior and thus its efficiency as a biological control agent. We studied the influence of these parameters on the behavior of Fopius arisanus (Sonan), an egg-pupal parasitoid of many Tephritidae. In the first experiment, we assessed in field cage assays the influence of temperature, humidity, light intensity, barometric pressure, and wind speed. Both flight and parasitism were mainly affected by temperature and humidity. However, because these two factors were strongly correlated in our experiments, the direct influence of each one cannot be specified. Flight activity was affected by variations in barometric pressure. In a second set of experiments, we conducted release and recapture assays with dyed insects to determine the influence of sex, mating status, egg load, age, and starvation on attraction toward infested fruit. Males were not attracted, suggesting that fruit are not a mating site. The egg load seemed to be a major parameter of foraging motivation. Finally, we showed that flight activity strongly decreased after 48 h of starvation. We observed a possible switch to food in the foraging motivation of starved females, but this result was impaired by poor recoveries: <10% of released females were recaptured after 96 h of starvation. We finally discuss the importance of these observations on the efficiency of F. arisanus as a biological control agent in tropical humid areas. PMID:19508801

  1. Vocal attractiveness increases by averaging.

    Science.gov (United States)

    Bruckert, Laetitia; Bestelmeyer, Patricia; Latinus, Marianne; Rouger, Julien; Charest, Ian; Rousselet, Guillaume A; Kawahara, Hideki; Belin, Pascal

    2010-01-26

    Vocal attractiveness has a profound influence on listeners-a bias known as the "what sounds beautiful is good" vocal attractiveness stereotype [1]-with tangible impact on a voice owner's success at mating, job applications, and/or elections. The prevailing view holds that attractive voices are those that signal desirable attributes in a potential mate [2-4]-e.g., lower pitch in male voices. However, this account does not explain our preferences in more general social contexts in which voices of both genders are evaluated. Here we show that averaging voices via auditory morphing [5] results in more attractive voices, irrespective of the speaker's or listener's gender. Moreover, we show that this phenomenon is largely explained by two independent by-products of averaging: a smoother voice texture (reduced aperiodicities) and a greater similarity in pitch and timbre with the average of all voices (reduced "distance to mean"). These results provide the first evidence for a phenomenon of vocal attractiveness increases by averaging, analogous to a well-established effect of facial averaging [6, 7]. They highlight prototype-based coding [8] as a central feature of voice perception, emphasizing the similarity in the mechanisms of face and voice perception.

  2. Vocal attractiveness increases by averaging.

    Science.gov (United States)

    Bruckert, Laetitia; Bestelmeyer, Patricia; Latinus, Marianne; Rouger, Julien; Charest, Ian; Rousselet, Guillaume A; Kawahara, Hideki; Belin, Pascal

    2010-01-26

    Vocal attractiveness has a profound influence on listeners-a bias known as the "what sounds beautiful is good" vocal attractiveness stereotype [1]-with tangible impact on a voice owner's success at mating, job applications, and/or elections. The prevailing view holds that attractive voices are those that signal desirable attributes in a potential mate [2-4]-e.g., lower pitch in male voices. However, this account does not explain our preferences in more general social contexts in which voices of both genders are evaluated. Here we show that averaging voices via auditory morphing [5] results in more attractive voices, irrespective of the speaker's or listener's gender. Moreover, we show that this phenomenon is largely explained by two independent by-products of averaging: a smoother voice texture (reduced aperiodicities) and a greater similarity in pitch and timbre with the average of all voices (reduced "distance to mean"). These results provide the first evidence for a phenomenon of vocal attractiveness increases by averaging, analogous to a well-established effect of facial averaging [6, 7]. They highlight prototype-based coding [8] as a central feature of voice perception, emphasizing the similarity in the mechanisms of face and voice perception. PMID:20129047

  3. Histories of host shifts and cospeciation among free-living parasitoids of Rhagoletis flies.

    Science.gov (United States)

    Hamerlinck, G; Hulbert, D; Hood, G R; Smith, J J; Forbes, A A

    2016-09-01

    Host shifts by specialist insects can lead to reproductive isolation between insect populations that use different hosts, promoting diversification. When both a phytophagous insect and its ancestrally associated parasitoid shift to the same novel host plant, they may cospeciate. However, because adult parasitoids are free living, they can also colonize novel host insects and diversify independent of their ancestral host insect. Although shifts of parasitoids to new insect hosts have been documented in ecological time, the long-term importance of such shifts to parasitoid diversity has not been evaluated. We used a genus of flies with a history of speciation via host shifting (Rhagoletis [Diptera: Tephritidae]) and three associated hymenopteran parasitoid genera (Diachasma, Coptera and Utetes) to examine cophylogenetic relationships between parasitoids and their host insects. We inferred phylogenies of Rhagoletis, Diachasma, Coptera and Utetes and used distance-based cophylogenetic methods (ParaFit and PACo) to assess congruence between fly and parasitoid trees. We used an event-based method with a free-living parasitoid cost model to reconstruct cophylogenetic histories of each parasitoid genus and Rhagoletis. We found that the current species diversity and host-parasitoid associations between the Rhagoletis flies and parasitoids are the primary result of ancient cospeciation events. Parasitoid shifts to ancestrally unrelated hosts primarily occur near the branch tips, suggesting that host shifts contribute to recent parasitoid species diversity but that these lineages may not persist over longer time periods. Our analyses also stress the importance of biologically informed cost models when investigating the coevolutionary histories of hosts and free-living parasitoids.

  4. Histories of host shifts and cospeciation among free-living parasitoids of Rhagoletis flies.

    Science.gov (United States)

    Hamerlinck, G; Hulbert, D; Hood, G R; Smith, J J; Forbes, A A

    2016-09-01

    Host shifts by specialist insects can lead to reproductive isolation between insect populations that use different hosts, promoting diversification. When both a phytophagous insect and its ancestrally associated parasitoid shift to the same novel host plant, they may cospeciate. However, because adult parasitoids are free living, they can also colonize novel host insects and diversify independent of their ancestral host insect. Although shifts of parasitoids to new insect hosts have been documented in ecological time, the long-term importance of such shifts to parasitoid diversity has not been evaluated. We used a genus of flies with a history of speciation via host shifting (Rhagoletis [Diptera: Tephritidae]) and three associated hymenopteran parasitoid genera (Diachasma, Coptera and Utetes) to examine cophylogenetic relationships between parasitoids and their host insects. We inferred phylogenies of Rhagoletis, Diachasma, Coptera and Utetes and used distance-based cophylogenetic methods (ParaFit and PACo) to assess congruence between fly and parasitoid trees. We used an event-based method with a free-living parasitoid cost model to reconstruct cophylogenetic histories of each parasitoid genus and Rhagoletis. We found that the current species diversity and host-parasitoid associations between the Rhagoletis flies and parasitoids are the primary result of ancient cospeciation events. Parasitoid shifts to ancestrally unrelated hosts primarily occur near the branch tips, suggesting that host shifts contribute to recent parasitoid species diversity but that these lineages may not persist over longer time periods. Our analyses also stress the importance of biologically informed cost models when investigating the coevolutionary histories of hosts and free-living parasitoids. PMID:27234648

  5. Physical Attractiveness and Courtship

    Science.gov (United States)

    Silverman, Irwin

    1971-01-01

    This study shows a high and disquieting degree of similarity in physical attractiveness between dating partners, and suggests also that more similar partners tend to form stronger romantic attachments. (Author)

  6. Pullback incremental attraction

    Directory of Open Access Journals (Sweden)

    Kloeden Peter E.

    2014-01-01

    Full Text Available A pullback incremental attraction, a nonautonomous version of incremental stability, is introduced for nonautonomous systems that may have unbounded limiting solutions. Its characterisation by a Lyapunov function is indicated

  7. Effectiveness of attract-and-kill systems using methyl eugenol incorporated with neonicotinoid insecticides against the oriental fruit fly (Diptera: Tephritidae).

    Science.gov (United States)

    Chuang, Yi-Yuan; Hou, Roger F

    2008-04-01

    Laboratory bioassays and field trials were conducted to evaluate an "attract-and-kill" system using methyl eugenol (ME) with neonicotinoid insecticides against male oriental fruit fly, Bactrocera dorsalis (Hendel) (Diptera: Tephritidae). In laboratory bioassays, mortality of male flies resulting from the conventional toxicant, naled was 98.3-100% at 24 through 72 h after treatment, whereas the neonicotinoid insecticides imidacloprid and acetamiprid caused only approximately 60-80% at 24 through 72 h after treatment. In the assays of residual effect, naled was persistent up to 96 wk, whereas imidacloprid or acetamiprid was persistent up to 150 wk, resulting in 38.9 or 61.2% male mortality, respectively. Imidacloprid, in particular, caused a delayed lethal effect on flies. In another experiment, male mortality within 28 wk from clothianidin, another neonicotinoid insecticide, was approximately 80% after exposure for 24 h, suggesting a delayed lethal effect similar to those treated with imidacloprid, and mortality was up to 91.8%, if observed, 72 h after treatment. In field trials, attractiveness was similar between ME alone and ME incorporated with naled or neonicotinoids, indicating that addition of these insecticides to ME in traps is not repellent to B. dorsalis males. Using an improved wick-typed trap with longer attractiveness for simulating field application, addition of imidacloprid or acetamiprid maintained 40.1 or 64.3% male mortality, respectively, when assayed once every 2 wk from traps placed in orchards for 42 wk without changing the poison, whereas incorporation with naled resulted in as high as 98.1% after 34 wk and approximately 80% at 42 wk, indicating that persistence is increased compared with sugarcane fiberboard blocks for carrying poison attractants. This study also suggests that neonicotinoid insecticides could be used as an alternative for broad-spectrum insecticides as toxicants in fly traps. PMID:18459398

  8. Physical attractiveness, employment and earnings

    OpenAIRE

    Pfeifer, Christian

    2011-01-01

    Survey data is used to estimate the impact of physical attractiveness rated by the interviewer as well as by the respondent on employment probability and labor income of men and women. In addition to mean linear and non-linear effects on earnings, simultaneous quantile regressions are applied to analyze heterogeneity across the wage distribution.

  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. P

  10. Effects of different animal manures on attraction and reproductive behaviors of common house fly, Musca domestica L.

    Science.gov (United States)

    Shah, Rizwan Mustafa; Azhar, Faheem; Shad, Sarfraz Ali; Walker, William B; Azeem, Muhammad; Binyameen, Muhammad

    2016-09-01

    Insects rely mainly on their well-developed and highly sophisticated olfactory system to discriminate volatile cues released from host and nonhost substances, mates, oviposition substrates, and food sources. Onset of first mating, mating duration, and onset of first oviposition, oviposition period, fecundity (number of eggs laid by a female), and longevity of freshly emerged Musca domestica L. (Diptera: Muscidae) adults were observed in the presence of different animal manures: cow, horse, donkey, poultry, and an artificial diet. The M. domestica adults exposed to horse manure showed a delay in onset of first mating and first oviposition, prolonged mating duration, and reduced fecundity compared to the artificial diet (control). Likewise, the fecundity was reduced in the presence of donkey manure as compared to artificial diet. The onset of first mating was delayed and duration of first mating was shortened in the presence of cow manure as compared to artificial diet and no oviposition was observed throughout the duration of the experiment. However, the reproductive behaviors and all fitness measures in adults exposed to poultry manure were similar or even better, compared to the artificial diet. Surprisingly, in a free-choice attraction assay, the highest numbers of adult flies were attracted toward the cow manure as compared to all other manures as well as the artificial diet. However, the numbers of flies captured in all other types of manures were not different than the artificial diet (control). Furthermore, chemical analysis of headspace samples of manures revealed qualitative differences in odor (volatile) profiles of all manures and artificial diet, indicating that behavioral differences could be due to the differences in the volatile chemistry of the adult ovipositional substrates and larval growth mediums. This study may contribute toward both understanding the linkage between ecological adaptations and host selection mechanisms and the development of

  11. Effects of different animal manures on attraction and reproductive behaviors of common house fly, Musca domestica L.

    Science.gov (United States)

    Shah, Rizwan Mustafa; Azhar, Faheem; Shad, Sarfraz Ali; Walker, William B; Azeem, Muhammad; Binyameen, Muhammad

    2016-09-01

    Insects rely mainly on their well-developed and highly sophisticated olfactory system to discriminate volatile cues released from host and nonhost substances, mates, oviposition substrates, and food sources. Onset of first mating, mating duration, and onset of first oviposition, oviposition period, fecundity (number of eggs laid by a female), and longevity of freshly emerged Musca domestica L. (Diptera: Muscidae) adults were observed in the presence of different animal manures: cow, horse, donkey, poultry, and an artificial diet. The M. domestica adults exposed to horse manure showed a delay in onset of first mating and first oviposition, prolonged mating duration, and reduced fecundity compared to the artificial diet (control). Likewise, the fecundity was reduced in the presence of donkey manure as compared to artificial diet. The onset of first mating was delayed and duration of first mating was shortened in the presence of cow manure as compared to artificial diet and no oviposition was observed throughout the duration of the experiment. However, the reproductive behaviors and all fitness measures in adults exposed to poultry manure were similar or even better, compared to the artificial diet. Surprisingly, in a free-choice attraction assay, the highest numbers of adult flies were attracted toward the cow manure as compared to all other manures as well as the artificial diet. However, the numbers of flies captured in all other types of manures were not different than the artificial diet (control). Furthermore, chemical analysis of headspace samples of manures revealed qualitative differences in odor (volatile) profiles of all manures and artificial diet, indicating that behavioral differences could be due to the differences in the volatile chemistry of the adult ovipositional substrates and larval growth mediums. This study may contribute toward both understanding the linkage between ecological adaptations and host selection mechanisms and the development of

  12. 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

  13. Transgenic GNA expressing potato plants augment the beneficial biocontrol of Lacanobia oleracea (Lepidoptera; Noctuidae) by the parasitoid Eulophus pennicornis (Hymenoptera; Eulophidae).

    Science.gov (United States)

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

    2001-01-01

    The effect of expressing the gene encoding snowdrop lectin (Galanthus nivalis agglutinin, GNA) in transgenic potato plants, on parasitism of the phytophagous insect pest Lacanobia oleracea by the gregarious ectoparasitoid Eulophus pennicornis, was investigated in glasshouse trials. Expression of GNA (approx. 1.0% total soluble protein) by transgenic plants significantly reduced the level of pest damage, thus confirming previous studies. Furthermore, the presence of the parasitoid significantly reduced the levels of damage incurred either by the transgenic or control plants when compared to those plants grown in the absence of the parasitoid. For the GNA expressing plants the presence of the parasitoid resulted in further reductions (ca. 21%) in the level of damage caused by the pest species. The ability of the wasp to parasitise and subsequently develop on the pest larvae was not altered by the presence of GNA in the diet of the host. E. pennicornis progeny that developed on L. oleracea reared on GNA expressing plants showed no significant alteration in fecundity when compared with wasps that had developed on hosts fed on control potato plants, although mean size and longevity of female parasitoids was significantly reduced. The number of F2 progeny produced by parasitoids derived from hosts fed on GNA expressing plants was not significantly different to those produced by parasitoids from hosts fed control plants. Results from the present study demonstrate that the use of transgenic plants expressing insecticidal proteins can be compatible with the deployment of beneficial insects and that the two factors may interact in a positive manner.

  14. Indirect competition facilitates widespread displacement of one naturalized parasitoid of imported fire ants by another.

    Science.gov (United States)

    LeBrun, E G; Plowes, R M; Gilbert, L E

    2009-05-01

    Species abundances in natural systems are usually close to some equilibrium, making mechanisms that maintain or prevent species coexistence difficult to discern. Biological control projects provide an opportunity to observe systems transition between equilibriums as a result of the influence of the newly introduced species. In the southeastern United States and Texas, species of phorid fly parasitoids are being sequentially introduced as control agents for imported fire ants. The first two species introduced, Pseudacteon tricuspis and P. curvatus, partition the host niche based upon body size and co-exist broadly in their native range in Argentina, indicating they would form a co-existing and complementary suite of parasitoids in North America. This study examines the interaction between these parasitoids at multiple temporal and spatial scales. Surprisingly, data at all scales reveal that as P. curvatus establishes at a site it competitively displaces P. tricuspis. However, the speed of this reduction appears to differ between ecoregions, suggesting that the rate of displacement depends on environment. At the site where P. curvatus has been established the longest, this population interaction approaches complete displacement. Tests of potential mechanisms causing this displacement reveal that direct competition for host workers alters the operational sex ratio of the P. tricuspis population, but the strength of this effect is insufficient to explain the displacement. Experiments reveal the operation of a strong, indirect effect whereby locally common species preempt reproductive opportunities from rarer species by inducing host behavioral defenses. Finally, a re-examination of published data from their native range reveals that a previously overlooked negative relationship between the densities of these two species also exists there, suggesting that the same processes as those reported here also operate in South America. PMID:19537540

  15. A statistical model of facial attractiveness.

    Science.gov (United States)

    Said, Christopher P; Todorov, Alexander

    2011-09-01

    Previous research has identified facial averageness and sexual dimorphism as important factors in facial attractiveness. The averageness and sexual dimorphism accounts provide important first steps in understanding what makes faces attractive, and should be valued for their parsimony. However, we show that they explain relatively little of the variance in facial attractiveness, particularly for male faces. As an alternative to these accounts, we built a regression model that defines attractiveness as a function of a face's position in a multidimensional face space. The model provides much more predictive power than the averageness and sexual dimorphism accounts and reveals previously unreported components of attractiveness. The model shows that averageness is attractive in some dimensions but not in others and resolves previous contradictory reports about the effects of sexual dimorphism on the attractiveness of male faces.

  16. The Putative Son's Attractiveness Alters the Perceived Attractiveness of the Putative Father.

    Science.gov (United States)

    Prokop, Pavol

    2015-08-01

    A body of literature has investigated female mate choice in the pre-mating context (pre-mating sexual selection). Humans, however, are long-living mammals forming pair-bonds which sequentially produce offspring. Post-mating evaluations of a partner's attractiveness may thus significantly influence the reproductive success of men and women. I tested herein the theory that the attractiveness of putative sons provides extra information about the genetic quality of fathers, thereby influencing fathers' attractiveness across three studies. As predicted, facially attractive boys were more frequently attributed to attractive putative fathers and vice versa (Study 1). Furthermore, priming with an attractive putative son increased the attractiveness of the putative father with the reverse being true for unattractive putative sons. When putative fathers were presented as stepfathers, the effect of the boy's attractiveness on the stepfather's attractiveness was lower and less consistent (Study 2). This suggests that the presence of an attractive boy has the strongest effect on the perceived attractiveness of putative fathers rather than on non-fathers. The generalized effect of priming with beautiful non-human objects also exists, but its effect is much weaker compared with the effects of putative biological sons (Study 3). Overall, this study highlighted the importance of post-mating sexual selection in humans and suggests that the heritable attractive traits of men are also evaluated by females after mating and/or may be used by females in mate poaching. PMID:25731909

  17. First record of Closterocerus chamaeleon, parasitoid of the Eucalyptus Gall Wasp Ophelimus maskelli (Hymenoptera, Chalcidoidea, Eulophidae, in the New World

    Directory of Open Access Journals (Sweden)

    Roger A. Burks

    2015-05-01

    Full Text Available The uniparental parasitoid Closterocerus chamaeleon (Girault is discovered to be fortuitously present on a population of the invasive Eucalyptus Gall Wasp Ophelimus maskelli (Ashmead in Riverside, California. This is the first report from the New World of C. chamaeleon, which has proven to be a highly effective natural enemy of O. maskelli in the Mediterranean Basin. The taxonomy and identification of C. chamaeleon is discussed.

  18. Cytogenetic analysis of three species of Pseudacteon (Diptera, Phoridae) parasitoids of the fire ants using standard and molecular techniques

    OpenAIRE

    Mónica G. Chirino; Patricia J. Folgarait; Gilbert, Lawrence E; Silvia Lanzavecchia; Papeschi, Alba G.

    2009-01-01

    Pseudacteon flies, parasitoids of worker ants, are being intensively studied as potentially effective agents in the biological control of the invasive pest fire ant genus Solenopsis (Hymenoptera: Formicidae). This is the first attempt to describe the karyotype of P. curvatus Borgmeier, P. nocens Borgmeier and P. tricuspis Borgmeier. The three species possess 2n = 6; chromosomes I and II were metacentric in the three species, but chromosome pair III was subtelocentric in P. curvatus and P. tri...

  19. Suppressive effects of Bifidobacterium longum on the production of Th2-attracting chemokines induced with T cell-antigen-presenting cell interactions.

    Science.gov (United States)

    Iwabuchi, Noriyuki; Takahashi, Noritoshi; Xiao, Jin-Zhong; Yonezawa, Sumiko; Yaeshima, Tomoko; Iwatsuki, Keiji; Hachimura, Satoshi

    2009-04-01

    In human trials, Bifidobacterium longum BB536 alleviates subjective symptoms of Japanese cedar pollinosis, an IgE-mediated type I allergy caused by exposure to Japanese cedar, and significantly suppresses the increase of plasma thymus- and activation-regulated chemokine (TARC) associated with pollen dispersion. In the present study, we investigated the suppressive effects of BB536 on the production of T helper type 2 (Th2)-attracting chemokines, such as TARC and macrophage-derived chemokine (MDC), together with the mechanisms of their production. Murine splenocytes were cultured with heat-killed BB536, and the levels of Th2-attracting chemokines in the supernatants were measured. TARC and MDC were produced in cultures without stimulation, and the production was significantly suppressed by BB536. These chemokines were produced by antigen-presenting cells (APCs) of splenocytes stimulated with an anti-CD40 antibody. Furthermore, TARC production was induced with granulocyte macrophage colony-stimulating factor that was produced by T cells and dendritic cells. BB536 suppressed MDC production induced with the anti-CD40 antibody by APCs from the spleen, mesenteric lymph nodes (MLNs) and Peyer's patches, and it suppressed TARC production by APCs from the spleen and MLNs. These results indicate that BB536 suppresses the production of Th2-attracting chemokines induced by the T cell-APC interaction, suggesting a novel mechanism for alleviating symptoms of allergic disorders by probiotics.

  20. 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.

  1. Biology of Habrobracon gelechiae (Hymenoptera: Braconidae), as a parasitoid of the obliquebanded leafroller (Lepidoptera: Tortricidae).

    Science.gov (United States)

    Daane, Kent M; Wang, Xingeng; Duerr, Sean S; Kuhn, Emily J; Son, Youngsoo; Yokota, Glenn Y

    2013-02-01

    Habrobracon gelechiae Ashmead (Hymenoptera: Braconidae) was studied as a parasitoid of the obliquebanded leafroller, Choristoneura rosaceana (Harris) (Lepidoptera: Tortricidae) in California pistachio (Pistacia vera L.) orchards. Ovipositional behavior, adult longevity and fecundity, and the effects of temperature on developmental time and survival were determined. Habrobracon gelechiae develops as a gregarious, ectoparasitic idiobiont on late-instar C. rosaceana larvae. At 25°C, adult female wasps survived longer when provided honey and water (35.4 ± 4.9 d) or honey, water, and host larvae (34.4 ± 2.4 d) than when provided water (8.9 ± 1.1 d) or no food (5.9 ± 0.8 d). Over the adult lifespan, females parasitized 20.6 ± 2.1 hosts and deposited 228.8 ± 24.6 eggs. The intrinsic rate of increase was 0.24, the mean generation time was 18.15 d, and the double time 2.88 d. At constant temperatures, H. gelechiae successfully developed (egg to adult) from 15 to 35 °C. The developmental rate was fit to a nonlinear model, providing estimates of the parasitoid's lower (10.5 °C), upper (36.0 °C), and optimal (33.3 °C) development temperatures. Based on a linear model, 155 degree days were estimated for egg to adult eclosion. Temperature-dependent nonlinear model of survival showed similar shape with the model of development rate. The wasp developed under two diurnal temperature regimes, with 31.0 ± 13.3% survival at low (4-15 °C) and 63.0 ± 11.4% survival at high (15-35 °C) temperature regimes. The results are discussed with respect to H. gelechiae potential as a parasitoid of C. rosaceana in California's San Joaquin Valley. PMID:23339791

  2. Sugar convertibility in the parasitoid Cotesia glomerata (Hymenoptera: Braconidae)

    NARCIS (Netherlands)

    Hausmann, C.; Wäckers, F.L.; Dorn, S.

    2005-01-01

    Lack of suitable sugar sources for adult parasitic wasps is an important cause of failure in biological control programs, but the metabolic constraints of sugar feeding are poorly understood. Here we investigated the suitability of 11 naturally occurring sugars as energy sources for the parasitoid C

  3. Foraging behavior of egg parasitoids exploiting chemical information

    NARCIS (Netherlands)

    Fatouros, N.E.; Dicke, M.; Mumm, R.; Meiners, T.; Hilker, M.

    2008-01-01

    Female parasitic wasps seek hosts for their offspring often in a dynamic environment. Foraging egg parasitoids rely on a variety of chemical cues originating from the adult host, host products, or the host plant rather than from the attacked host stage¿the insect egg itself. Besides pupae, insect eg

  4. Performance of secondary parasitoids on chemically defended and undefended hosts

    NARCIS (Netherlands)

    van Nouhuys, S.; Reudler, J.H.; Biere, A.; Harvey, J.A.

    2012-01-01

    Defensive chemicals produced by plants can travel up the food chain by being sequestered by herbivores, and then in turn being sequestered by their parasitoids. Insect species with wide host ranges are predicted to perform poorly in the face of specific chemical defence. However, a species at a high

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

    NARCIS (Netherlands)

    Silva, I.M.M.S.

    1999-01-01

    Egg parasitoids of the genus Trichogramma are used as biological control agents against lepidopterous pests. From the 180 species described world-wide, only 5 have large scale application. The development of better methods to select other Trichogramma species/strains is necessary for a more effectiv

  6. Foraging under incomplete information: parasitoid behaviour and community dynamics

    NARCIS (Netherlands)

    Vos, M.

    2001-01-01

    This thesis describes research on multitrophic interactions between parasitoids, herbivores and plants. These are all involved in a dynamic game of hide-and-seek. Insect herbivores may occur in different spatial distributions across plants. Some species occur in local clusters, while others have a m

  7. Impact of botanical pesticides derived from Melia azedarach and Azadirachta indica on the biology of two parasitoid species of the diamondback moth

    NARCIS (Netherlands)

    Charleston, D.S.; Kfir, R.; Dicke, M.; Vet, L.E.M.

    2005-01-01

    The effect of two botanical pesticides was tested on two species of parasitoids, Cotesia plutellae and Diadromus collaris. Aqueous leaf extracts from the syringa tree, Melia azedarach and commercial formulations from the neem tree, Azadirachta indica, Neemix 4.5 were investigated in the laboratory a

  8. 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.

  9. 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...

  10. 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

  11. 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

  12. Sunflower stem weevil and its larval parasitoids in native sunflowers: Is parasitoid abundance and diversity greater in the US Southwest?

    Science.gov (United States)

    Sunflower stem weevils (Cylindrocopturus adspersus) and their larval parasitoids were collected from stems of four native sunflower species (Helianthus annuus, H. nuttallii, H. pauciflorus, and H. petiolaris) from 147 sites across eight states in 2003 and 2005. Native H. annuus constituted the major...

  13. Impact of terbufos on Cotesia flavipes, a parasitoid of Diatraea saccharalis

    International Nuclear Information System (INIS)

    The effect of terbufos on larvae of Diatraea saccharalis and its parasitoid, Cotesia flavipes was evaluated in the laboratory. Bioassays were conducted to determine the dose response of non-parasitized larvae of D. saccharalis feeding on artificial diet contaminated with terbufos. From the dose-response curve based on larval fresh weight, sublethal doses ranging from 1.32 ppm to 108 ppm of terbufos were selected for further studying the effect of the insecticide on both species. Both parasitized and non-parasitized larvae were exposed to the selected sublethal doses of terbufos in the diet. Consumption of the insecticide by the host resulted in mortality of the parasitoid, increased length of its larval and pupal periods, decreased adult fresh weight and changes in sex proportions. These negative effects were more severe as the dose of the insecticide increased. D. saccharalis was also affected by terbufos; larvae showed abnormalities, the length of the larval and pupal periods increased and the proportion of the females was reduced. In a preliminary greenhouse bioassay, only traces of terbufos or its metabolites were found in treated maize plants and in tissue of D. saccharalis larvae feeding on them. (author)

  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. Diversity, population structure, and individual behaviour of parasitoids as seen using molecular markers.

    Science.gov (United States)

    van Nouhuys, Saskya

    2016-04-01

    Parasitoids have long been models for host-parasite interactions, and are important in biological control. Neutral molecular markers have become increasingly accessible tools, revealing previously unknown parasitoid diversity. Thus, insect communities are now seen as more speciose. They have also been found to be more complex, based on trophic links detected using bits of parasitoid DNA in hosts, and host DNA in adult parasitoids. At the population level molecular markers are used to determine the influence of factors such as host dynamics on parasitoid population structure. Finally, at the individual level, they are used to identify movement of individuals. Overall molecular markers greatly increase the value of parasitoid samples collected, for both basic and applied research, at all levels of study. PMID:27436653

  16. Biological Control of Solenopsis Fire Ants by Pseudacteon Parasitoids: Theory and Practice

    Directory of Open Access Journals (Sweden)

    Lloyd W. Morrison

    2012-01-01

    Full Text Available Pseudacteon parasitoids are potential biocontrol agents of invasive Solenopsis fire ants. Pseudacteon species that parasitize the invasive S. invicta Buren and S. richteri Forel have been introduced to, and naturally dispersed across, the southeastern USA, although there is no evidence yet that Solenopsis host ant populations have decreased. The ability of introduced Pseudacteon species to regulate Solenopsis populations will depend upon the relative importance of top-down effects in the recipient communities. In this paper, I examine the characteristics of the Pseudacteon/Solenopsis parasitoid/host system and evaluate the extent to which research findings are consistent with top-down control. Laboratory and field experiments evaluating Solenopsis population regulation have been equivocal, and overall the available evidence provides little support for strong top-down effects in this system. Competitive exclusion may occur among introduced Pseudacteon species, and future efforts at biological control are likely to be more efficacious if they focus on other types of natural enemies.

  17. Susceptibility of the Parasitoid Phymastichus coffea LaSalle (Hymenoptera: Eulophidae) to Beauveria bassiana under laboratory conditions

    International Nuclear Information System (INIS)

    The coffee berry borer, Hypothenemus hampei (Ferrari) (Coleoptera: Curculionidae), is the most important coffee pest worldwide. Beauveria bassiana is a generalist entomopathogenic fungus widely used by coffee farmers to control this pest and Phymastichus coffea LaSalle (Hymenoptera: Eulophidae) is an African endo parasitoid of H. hampei adults, recently imported to several Latin American and Caribbean countries to aid in the coffee berry borer control. The objective of this study was to determine if B. bassiana is detrimental to P. coffea. The susceptibility of the parasitoid was evaluated in terms of adult survivorship, mean lethal concentration (LC50), mean lethal time (LT50), reproduction and immature mortality. The main effect of the fungus resulted in reduction of adult longevity and mortality of 100% for immature stages of this parasitoid. The LC50 for adults was 0.11% equivalent to 9.53 x 107 conidia/ml of B. bassiana and a LT50 of 29.4 h, equivalent to reduction of 22% of its normal longevity as an adult. P. coffea was capable of disseminating spores of B. bassiana to non-infected H. hampei adults, which could indirectly cause the death of its own progeny. These results could be valuable when considering the use of both organisms in the field, especially in an integrated pest management program. (author)

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

    NARCIS (Netherlands)

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

    2008-01-01

    Objective: Natural elements in the built healthcare environment have shown to hold potential stress-reducing properties. In order to shed light on the underlying mechanism of stress-reducing effects of nature, the present study investigates whether the stress-reducing effects of indoor plants occur

  20. Insects Can Count: Sensory Basis of Host Discrimination in Parasitoid Wasps Revealed

    OpenAIRE

    Sara Ruschioni; van Loon, Joop J. A.; Smid, Hans M; Joop C van Lenteren

    2015-01-01

    The solitary parasitoid Leptopilina heterotoma is one of the best studied organisms concerning the ecology, behaviour and physiology of host discrimination. Behavioural evidence shows that L. heterotoma uses its ovipositor to discriminate not only between parasitized and unparasitized Drosophila melanogaster larvae, but also to discriminate between hosts with different numbers of parasitoid eggs. The existing knowledge about how and when the parasitoid marks the host motivated us to unravel t...

  1. Parasitoids of Leafminers (Diptera: Agromyzidae) from Southeast Turkey with 3 New Records

    OpenAIRE

    ÇIKMAN, Emine; BEYARSLAN, Ahmet; CİVELEK, Hasan Sungur

    2006-01-01

    This study was carried out in order to determine parasitoid species of the family Agromyzidae (Diptera) in Diyarbakır and Mardin provinces during 2002-2004. Infested leaves with leafminer larvae were collected from both cultivated and non-cultivated plants twice a month. The adult parasitoids were obtained by rearing from infested leaves in the laboratory. Five parasitoid species belonging to the Braconidae (Hymenoptera) were found. These species, Bracon kirgisorum Telenga, 1936, Opius basali...

  2. Ação transovariana de lufenuron (50 g/l sobre adultos de Spodoptera Frugiperda (j. e. smith (Lepidoptera: Noctuidae e seu efeito sobre o parasitóide de ovos Trichogramma pretiosum Riley (Hymenoptera: Trichogrammatidae Transovarian action of lufenuron on adults of Spodoptera frugiperda (J. E. Smith (Lepidoptera: Noctuidae and its effect on the parasitoid Trichogramma pretiosum Riley (Hymenoptera: Trichogrammatidae

    Directory of Open Access Journals (Sweden)

    Dirceu Pratissoli

    2004-02-01

    Full Text Available Avaliaram-se a ação transovariana do lufenuron em Spodoptera frugiperda e sua seletividade ao parasitóide de ovos Trichogramma pretiosum. Casais da praga foram isolados em gaiolas de PVC e alimentados com solução de mel a 10% na testemunha, e nos outros tratamentos, foi adicionado à solução de mel o regulador de crescimento de insetos Match® CE nas proporções de 12,5; 15,0 e 17,5 g i.a/l. Para verificação da ação transovariana, diariamente foram coletadas as posturas, contado o número de ovos e, posteriormente, o número de larvas eclodidas. Quarenta ovos provenientes de cada tratamento foram colados em cartelas de papel (cartolina e expostos ao parasitismo, dentro de tubos de vidro de 1,0 x 3,5 cm, contendo uma fêmea de T. pretiosum no seu interior. Cartelas contendo 40 ovos de S. frugiperda foram imersas em soluções de lufenuron com a mesma concentração dos tratamentos anteriores e, posteriormente, expostas ao parasitismo por T. pretiosum. O lufenuron afetou consideravelmente a viabilidade dos ovos de S. frugiperda. Pelos resultados obtidos nos ensaios, relativos ao parasitóide, demonstram-se a seletividade do regulador de crescimento lufenuron e a possibilidade de sua utilização em programas de Manejo Integrado, juntamente com o parasitóide de ovos T. pretiosum.The transovarian action of insect growth regulator lufenuron in Spodoptera frugiperda (Lepidoptera: Noctuidae and its effects on the egg parasitoid Trichogramma pretiosum (Hymenoptera: Trichogrammatidae, were evaluated. Pest couples were isolated in PVC's cages and provided with 10% honey solution as control. In the others treatments, the honey solution was mixed with the insect growth regulator Match® CE using the following concentrations of 12.5; 15.0 and 17.5 g i.a./l. For verification of the transovarian action, the eggs were collected daily, with the number of the hatched larvae being subsequently counted. Forty eggs from each treatment were fixed in

  3. Dissociating Averageness and Attractiveness: Attractive Faces Are Not Always Average

    Science.gov (United States)

    DeBruine, Lisa M.; Jones, Benedict C.; Unger, Layla; Little, Anthony C.; Feinberg, David R.

    2007-01-01

    Although the averageness hypothesis of facial attractiveness proposes that the attractiveness of faces is mostly a consequence of their averageness, 1 study has shown that caricaturing highly attractive faces makes them mathematically less average but more attractive. Here the authors systematically test the averageness hypothesis in 5 experiments…

  4. 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.

  5. The neurobiology of attraction.

    Science.gov (United States)

    Marazziti, D; Cassano, G B

    2003-01-01

    In these last years, emotions and feelings, such as attachment, couple and parental bonding and even love, typical of higher mammals, neglected for centuries by experimental sciences, have become the topic of extensive neuroscientific research in order to elucidate their biological mechanisms. Several observations have highlighted the role of monoamines and of neuropeptides, in particular oxytocin, vasopressin and opioids, but this is only the beginning of the story. Love, the most typical human feeling, can be viewed as a dynamic process that represents the result of different components probably subserved by distinct neural substrates at different times. As such, some steps can be identified, in particular its beginning, which is the process of attraction, followed by the attachment process that, in some cases, can last forever. This paper will make some general speculations on the attraction process, in the light of the experience of the Authors. PMID:12834023

  6. Chemistry of sex attraction.

    OpenAIRE

    Roelofs, W L

    1995-01-01

    The chemical communication system used to attract mates involves not only the overt chemical signals but also indirectly a great deal of chemistry in the emitter and receiver. As an example, in emitting female moths, this includes enzymes (and cofactors, mRNA, genes) of the pheromone biosynthetic pathways, hormones (and genes) involved in controlling pheromone production, receptors and second messengers for the hormones, and host plant cues that control release of the hormone. In receiving ma...

  7. Control of cabbage diamondback moth by integrating the sterile insect technique and parasitoids in Myanmar

    International Nuclear Information System (INIS)

    Full text: Mass rearing of DBM was carried out on cauliflower, cabbage, mustard and artificial diet. Pupae collection on aluminum foil was tested. Storage of pupae and larvae was carried out in 16 deg. C incubator and 5-10 deg. C refrigerator. Different doses of gamma radiation: 10Kr, 15Kr and 20Kr were tested to established the effective gamma radiation dose. Each one hundred cabbage plants were selected and marked for regular observations of DBM populations in control plots to assess the frequency distribution of DBM adult population in cabbage fields. DBM larvae were collected in control plots to assess the rate of DBM larvae with the parasitoid - Cotesia plutellae in fields. Mass rearing of DBM on cauliflower was better than rearing on cabbage, mustard and artificial diet. Pupae collection on cauliflower was better than those of cabbage, mustard and artificial diet. Pupae could be stored successfully for 2 weeks in 16 deg. C incubator and 5-10 deg. C refrigerator. DBM larvae reared on cauliflower could be stored for 7 days at 5-10 deg. c refrigerator. Radiation doses of 10Kr gave better results than 15 Kr and 20 Kr. 1-5 DBM adults were found in most of the plants during the season. Percentage of DBM larvae parasitised by the parasitoid - Cotesia plutellae was 30-40% in the field. (author)

  8. The role of geography and host abundance in the distribution of parasitoids of an alien pest.

    Science.gov (United States)

    Nováková, Petra; Holuša, Jaroslav; Horák, Jakub

    2016-01-01

    Chalcid wasps (Hymenoptera: Chalcidoidea) are probably the most effective and abundant parasitoids of the horse chestnut leaf miner (Cameraria ohridella), an alien pest in Europe that lacks specialized enemies. We studied how the species richness and abundance of chalcids are influenced by altitude, direction of an alien spread and host abundance of C. ohridella. We quantified the numbers and species richness of chalcid wasps and the numbers of C. ohridella that emerged from horse chestnut (Aesculus hippocastanum) leaf litter samples collected from 35 sites in the Czech Republic. Species richness of chalcids, which was considered an indicator of the possible adaptation of parasitoids to this alien host, was unrelated to C. ohridella abundance, direction of spread, or altitude. Chalcid abundance, which was considered an indicator of parasitism of the alien host, was strongly and positively related to C. ohridella abundance. Chalcid abundance was negatively related to direction of spread and positively related, although in a non-linear manner, to altitude. The relationship of chalcid abundance with direction of spread and altitude was weaker than that with C. ohridella abundance. The results provide evidence that biological control of the alien pest C. ohridella by natural enemies might develop in the future. PMID:26819849

  9. The role of geography and host abundance in the distribution of parasitoids of an alien pest

    Science.gov (United States)

    Nováková, Petra; Holuša, Jaroslav

    2016-01-01

    Chalcid wasps (Hymenoptera: Chalcidoidea) are probably the most effective and abundant parasitoids of the horse chestnut leaf miner (Cameraria ohridella), an alien pest in Europe that lacks specialized enemies. We studied how the species richness and abundance of chalcids are influenced by altitude, direction of an alien spread and host abundance of C. ohridella. We quantified the numbers and species richness of chalcid wasps and the numbers of C. ohridella that emerged from horse chestnut (Aesculus hippocastanum) leaf litter samples collected from 35 sites in the Czech Republic. Species richness of chalcids, which was considered an indicator of the possible adaptation of parasitoids to this alien host, was unrelated to C. ohridella abundance, direction of spread, or altitude. Chalcid abundance, which was considered an indicator of parasitism of the alien host, was strongly and positively related to C. ohridella abundance. Chalcid abundance was negatively related to direction of spread and positively related, although in a non-linear manner, to altitude. The relationship of chalcid abundance with direction of spread and altitude was weaker than that with C. ohridella abundance. The results provide evidence that biological control of the alien pest C. ohridella by natural enemies might develop in the future. PMID:26819849

  10. Interocular conflict attracts attention.

    Science.gov (United States)

    Paffen, Chris L E; Hessels, Roy S; Van der Stigchel, Stefan

    2012-02-01

    During binocular rivalry, perception alternates.between dissimilar images presented dichoptically. Since.its discovery, researchers have debated whether the phenomenon is subject to attentional control. While it is now clear that attentional control over binocular rivalry is possible, the opposite is less evident: Is interocular conflict (i.e., the situation leading to binocular rivalry) able to attract attention?In order to answer this question, we used a change blindness paradigm in which observers looked for salient changes in two alternating frames depicting natural scenes. Each frame contained two images: one for the left and one for the right eye. Changes occurring in a single image (monocular) were detected faster than those occurring in both images (binocular). In addition,monocular change detection was also faster than detection in fused versions of the changed and unchanged regions. These results show that interocular conflict is capable of attracting attention, since it guides visual attention toward salient changes that otherwise would remain unnoticed for longer. The results of a second experiment indicated that interocular conflict attracts attention during the first phase of presentation, a phase during which the stimulus is abnormally fused [added]. PMID:22167536

  11. Impressions of Counselors as a Function of Counselor Physical Attractiveness

    Science.gov (United States)

    Carter, Jean A.

    1978-01-01

    Research assessed the effects of counselor physical attractiveness and inter-actions between attractiveness and counselor subject sex. It is suggested that sex of counselor and client may play a more important role independently and in conjunction with attractiveness than does attractiveness alone in influencing impressions and expectations.…

  12. Fingertip aura and interpersonal attraction.

    Science.gov (United States)

    Murstein, B I; Hadjolian, S E

    1977-06-01

    Concluding from our survey of the literature that fingertip auras (Kirlian effect) might be associated with interpersonal attraction, four hypotheses were advanced to test this assertion. It was hypothesized that individuals would respond with bigger auras to (1) opposite-sex photographers as compared to same-sex photographers, (2) to seductive opposite-sex photographers as opposed to normally behaving opposite-sex photographers, (3) to opposite-sex unknown peers as opposed to same-sex unknown peers, and (4) to liked as opposed to disliked same-sex persons. All hypotheses except (2) were supported. The second hypothesis was significant in a direction contrary to hypothesis. Fingertip auras are seen as a promising measurement device in the study of interpersonal attraction. PMID:16367230

  13. 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.

  14. 6种饵料对小白鼠引诱作用的初步观察%Preliminary observation of the attracting effect of six mice baits

    Institute of Scientific and Technical Information of China (English)

    钟平生; 邓惠彩; 赵瑾; 郭国汉

    2011-01-01

    Objective To identify the most attractive mice baits for preparation of toxic baits. Methods The attracting effects of six types of bait (peanut, rice, potato, bean cake, fish bait, and cat food) on mice were determined in terms of the respective feeding coefficients. Results Mice showed different preferences for the six baits, of which potatoes and peanuts had the strongest attracting effects with feeding coefficients of 5.90 and 2.49, respectively, and average feeding rates of 60.71% and 25.61%, respectively. Bean cakes and rice followed with feeding coefficients of 1.08 and 1.16 and feeding rates of 14.49% and 11.94%, respectively. The attractive efficiency of fish baits and cat food were the lowest, with the feeding rates of 8.74% and 3.00%, respectively. Conclusion Potatoes and peanuts are the baits of choice when preparing poison baits for mice. Their attracting effects deteriorate with time and become the lowest beyond 48 hours. Furthermore, the nutritional balance or mixing of baits may be considered to improve palatability.%目的 寻找对小白鼠更具引诱力的饵料,为配制毒饵提供一定依据.方法 采用摄食系数测定6种不同饵料(花生、豆饼、稻谷、马铃薯、猫料、鱼饵)对小白鼠的引诱效果.结果 小白鼠对6种饵料的偏好性存在差异.其中马铃薯、花生对小白鼠的引诱效果最强,摄食系数为5.90和2.49,偏好性为优,平均取食率达60.71%和25.61%;豆饼和稻谷的引诱效果次之,摄食系数分别为1.08和1.16,偏好性也为优,取食率分别为14.49%和11.94%;鱼饵和猫料的引诱效果较弱,取食率分别仅为8.74%和3.00%,低于对照饵料——鼠粮的取食率(13.37%).结论 在配制鼠类毒饵时,可优先考虑更具引诱效果的马铃薯和花生;同时,随着投饵后时间的延长,持续引诱作用降低,其中以48 h后的减幅最大.此外,在研制灭鼠剂时,应考虑饵料的营养平衡或不同类型饵料的交替使用,以提高诱饵的适口性.

  15. Efeitos de atrativos e repelentes sobre o comportamento da abelha (Apis mellifera, l. Effect of attractants and repellents on the behavior of honey bees (Apis mellipera, L.

    Directory of Open Access Journals (Sweden)

    D.T. MALERBO-SOUZA

    1998-01-01

    Full Text Available O objetivo do presente ensaio foi testar diversas substâncias e verificar sua atratividade e repelência para abelhas, Apis mellifera, L. Para isso, foram realizados testes em discos próximos às colméias e em cana picada oferecida como alimentação para gado bovino confinado. Nos discos próximos à colméia, o produto mais atrativo foi Bee-Here e o mais repelente foi o óleo de citronela. No cocho para bovinos, o repelente mais efetivo foi n-octyl-acetato.The experiment aimed to study honey bee (Apis mellifera attractants and repellents in vitro and on chopped sugar cane for bovine feeding. Tests were performed on plates located near to the hives and on bovine-hods. On plates, Bee-Here® was the most attractive and citronela oil the most repellent. On bovine-hods the most effective was n-octyl-acetate.

  16. Series Solutions of Time-Fractional Host-Parasitoid Systems

    Science.gov (United States)

    Arafa, A. A. M.

    2011-12-01

    In this paper, Adomian's decomposition method (ADM) has been used for solving time-fractional host-parasitoid system. The derivatives are understood in the Caputo sense. The reason of using fractional order differential equations (FOD) is that FOD are naturally related to systems with memory which exists in most biological systems. Also they are closely related to fractals which are abundant in biological systems. Numerical example justifies the proposed scheme.

  17. Colony-level impacts of parasitoid flies on fire ants.

    OpenAIRE

    Mehdiabadi, Natasha J; Gilbert, Lawrence E

    2002-01-01

    The red imported fire ant is becoming a global ecological problem, having invaded the United States, Puerto Rico, New Zealand and, most recently, Australia. In its established areas, this pest is devastating natural biodiversity. Early attempts to halt fire ant expansion with pesticides actually enhanced its spread. Phorid fly parasitoids from South America have now been introduced into the United States as potential biological control agents of the red imported fire ant, but the impact of th...

  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. 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. PMID:15969827

  20. Toxicity of organic supplies for the egg parasitoid Telenomus podisi

    Directory of Open Access Journals (Sweden)

    Débora Mello da Silva

    2014-01-01

    Full Text Available Toxicity (dosage per hectare of: 1 Baculovirus anticarsia 140x109 cpi; 2 Bacillus thuringiensis 16.8g; 3 Azadirachtin-A, azadirachtin-B, nimbina and salamina 9.6 ppm; 4 Rotenoids 4 liters; 5 Nitrogen 1.3%, phosphorus 3.0% and total organic carbon 8.0% 3 liters; 6 Sodium silicate 2% 4 liters; 7 Copper 7% + calcium 3.3% 1.8 liters; 8 Sulfur 20% + quicklime 10% 1.8 liters; 9 Chlorpyrifos 384g; 10 Distilled H2O (control were evaluated for pupae and adults of Telenomus podisi. Treatments from 1 to 8 were in general harmless (class 1 to both pupae and adults of T. podisi. Among them, only treatment 5 and 7 presented slightly toxic to the parasitoid with a reduction in parasitism 5 days after F1 parasitoid emergence. Differently, the chlorpyrifos was classified as slightly harmful (class 2 or moderately harmful (class 3. Therefore, the use of the tested organic agricultural supplies in the production of organic soybean is viable, without impairing the natural biological control allowed by this egg parasitoid. Chlorpyrifos use, on the other hand, is not allowed in organic soybean, but even on convention crop production, could whenever possible, be replaced by other products more compatible with T. podisi preservation.

  1. 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 cages. In this study, replacing plastic mesh 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. PMID:23243226

  2. Comparison of effectiveness of various artificial reef materials for fish attraction%不同材料人工鱼礁生物诱集效果的比较

    Institute of Scientific and Technical Information of China (English)

    江艳娥; 陈丕茂; 林昭进; 方展强

    2013-01-01

    参考相关资料对比水泥类、油井类、舰船类及其他类型人工鱼礁对海洋生物诱集效果,探讨不同材料人工鱼礁在诱集效果上的差异.结果表明,人工鱼礁区生物诱集效果高出天然礁区(对照区)的比率达68.75%.不同材料类型人工鱼礁的生物诱集效果存在差异:水泥类人工鱼礁生物诱集效果高于天然礁区的比率为71.43%;油井类人工鱼礁生物诱集效果高于天然礁区的比率为50.00%;舰船类人工鱼礁生物诱集效果高于天然礁区的比率为100.00%;其他类人工鱼礁生物诱集效果高于天然礁区的比率为80.00%.研究资料分析表明人工鱼礁的建设,需要更多地结合海洋物理、海洋化学、海洋生物等方面的知识,以提高人工鱼礁对海洋生物的增殖效果,促进其生态效益、经济效益和社会效益共同提高.%Analyzed the effectiveness of fish attraction on artificial reef of concrete,oil jetty,vessel and other materials,differences of fish attraction on these artificial reefs versus natural reefs (control sites) have been recognized.68.75% of all these analyzed artificial reefs have higher records of fish attraction than that in natural reefs.The record is 71.43% in concrete artificial reefs,50.00% in oil jetty artificial reefs,100% in vessel artificial reefs,80.00% in other material artificial reefs.In conclusion,the following advices could favor the fish attraction:smallscale isolated artificial reefs,concrete material with much holes and shade if possible and high variation of model appearance.Not only these factors,but also factors of physic,chemical and biology would work together on artificial reefs to attract marine organisms for ecological,economic and social benefits.

  3. 10种人工鱼礁模型对黑鲷幼鱼的诱集效果%Attraction effect of various artificial reef models on Sparus macrocephalus

    Institute of Scientific and Technical Information of China (English)

    周艳波; 蔡文贵; 陈海刚; 陈丕茂; 吕国敏; 贾晓平

    2011-01-01

    Artificial reef was used in marine ranch to improve the marine ecological environment and enhance the fishery resources. Attractive effects of artificial reef may be attributed to creating habitat, shelter and spawning ground for the various kinds of fish, therefore positively affect the breeding and growth of the fish. In recent years, artificial reef construction programs have been rapidly developed in China. However, the knowledge of the effect of artificial reef on marine ecological environment is limited. The present study aimed to determine the influence of materials, structure and combination on the attractive effects of the artificial reefs and therefore provide useful data and information for the development of artificial reef construction. In the present study, the effects of ten kinds of artificial reef models with different shapes, which have been deployed in Yangmeikeng reef area, on the behavioral responses of the fish Sparus macrocephalus and the fish attraction effects of the artificial reef models were analyzed and compared with those without the artificial reef model in the trough. The result showed that in the condition without the artificial reef model in the trough, the fish liked to stay in radius of the center trough area within 40 - 70 cm. while the fish are more dispersed in the trough. After the artificial model was put into the troughs, the fish liked to stay in radius of the center trough area within 20 - 50 cm while No. 1 reef-No. 8 reef were put into the trough, the fish liked to stay in radius of the center trough area within 10 -40 cm while No. 9 reef and No. 10 reef were put into the trough. The average occurring rate of the fish inside and near the reef areas all increased, while comparing fish occurring rates in artificial reef areas with or without artificial reef. The analysis results showed that all of the ten artificial reef models have obvious attraction effects on S. macrocephalus,especially for model NO. 10. Its attraction

  4. Stereoselective Chlorination and Bromination of Enamides and Enamines via an Electrostatic Attraction Effect Using (1,1-Diacetoxyiodo)benzene and a Halide Source.

    Science.gov (United States)

    Xing, Linlin; Li, Chunbao

    2015-10-16

    The direct chlorination and bromination of (E)-enamines and (Z)-enamides to the corresponding (Z)-configurated α-chloroenamines, α-bromoenamines, and α-chloroenamides have been realized using NiCl2·6H2O or tetrabutyl ammonium bromide as a halide source and (1,1-diacetoxyiodo)benzene as an oxidant. The high stereoselective reactions which produce products with only (Z)-configurations can be attributed to the structure of the intermediates, the conformations of which are controlled by the electrostatic attractions between the positively charged nitrogen atoms and the oxygen atoms of the carbonyl group. This type of electrostatic effect has never been reported in olefin halogenations. For this reason, the three-membered bromonium ion is only a minor intermediate in the enamine bromination pathway. These methods open pathways to prepare α-chloroenamines and α-chloroenamides, which are not accessible via the currently used methods. PMID:26421836

  5. 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. PMID:18773730

  6. A hitch-hiker’s guide to parasitism: the chemical ecology of phoretic insect parasitoids

    NARCIS (Netherlands)

    Huigens, M.E.; Fatouros, N.E.

    2013-01-01

    Phoretic arthropods use other animals as vehicles to migrate to new environments. Among insect parasitoids, phoresy is almost exclusively restricted to minute wasp species that develop in or on the smallest and most inconspicuous life stage of their host: the egg. Females of about 35 egg parasitoid

  7. 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.

  8. 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

    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...

  9. 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.

  10. Egg distributions and the information a solitary parasitoid has and uses for its oviposition decisions

    NARCIS (Netherlands)

    Hemerik, L.; Hoeven, van der N.; Alphen, van J.J.M.

    2002-01-01

    Approximately three decades ago the question was first answered “whether parasitoids are able to assess the number or origin of eggs in a host” for a solitary parasitoid, Leptopilina heterotoma, by fitting theoretically derived distributions to empirical ones. We extend the set of different theoreti

  11. Attractions between charged colloids at water interfaces

    OpenAIRE

    Oettel, M.; Dominguez, A; Dietrich, S.

    2005-01-01

    The effective potential between charged colloids trapped at water interfaces is analyzed. It consists of a repulsive electrostatic and an attractive capillary part which asymptotically both show dipole--like behavior. For sufficiently large colloid charges, the capillary attraction dominates at large separations. The total effective potential exhibits a minimum at intermediate separations if the Debye screening length of water and the colloid radius are of comparable size.

  12. Parasitism overrides herbivore identity allowing hyperparasitoids to locate their parasitoid host using herbivore-induced plant volatiles.

    Science.gov (United States)

    Zhu, Feng; Broekgaarden, Colette; Weldegergis, Berhane T; Harvey, Jeffrey A; Vosman, Ben; Dicke, Marcel; Poelman, Erik H

    2015-06-01

    Foraging success of predators profoundly depends on reliable and detectable cues indicating the presence of their often inconspicuous prey. Carnivorous insects rely on chemical cues to optimize foraging efficiency. Hyperparasitoids that lay their eggs in the larvae or pupae of parasitic wasps may find their parasitoid hosts developing in different herbivores. They can use herbivore-induced plant volatiles (HIPVs) to locate parasitized caterpillars. Because different herbivore species induce different HIPV emission from plants, hyperparasitoids may have to deal with large variation in volatile information that indicates host presence. In this study, we used an ecogenomics approach to first address whether parasitized caterpillars of two herbivore species (Pieris rapae and P. brassicae) induce similar transcriptional and metabolomic responses in wild Brassica oleracea plants and, second, whether hyperparasitoids Lysibia nana are able to discriminate between these induced plant responses to locate their parasitoid host in different herbivores under both laboratory and field conditions. Our study revealed that both herbivore identity and parasitism affect plant transcriptional and metabolic responses to herbivory. We also found that hyperparasitoids are able to respond to HIPVs released by wild B. oleracea under both laboratory and field conditions. In addition, we observed stronger attraction of hyperparasitoids to HIPVs when plants were infested with parasitized caterpillars. However, hyperparasitoids were equally attracted to plants infested by either herbivore species. Our results indicate that parasitism plays a major role in HIPV-mediated plant-hyperparasitoid interactions. Furthermore, these findings also indicate that plant trait-mediated indirect interaction networks play important roles in community-wide species interactions. PMID:25789566

  13. Parasitoids and hyperparasitoids (Hymenoptera) on aphids (Hemiptera) infesting citrus in east Mediterranean region of Turkey.

    Science.gov (United States)

    Satar, Serdar; Satar, Gül; Karacaoğlu, Mehmet; Uygun, Nedim; Kavallieratos, Nickolas G; Starý, Petr; Athanassiou, Christos G

    2014-01-01

    The aphids, aphid parasitoids, and hyperparasitoids found in citrus orchards, the parasitoids' and hyperparasitoids' seasonal abundance, and the plant-aphid-parasitoid relationships in Hatay, Osmaniye, Adana, and Mersin provinces of the east Mediterranean region of Turkey are presented in the present 2-yr study. Aphidius colemani Viereck, Binodoxys angelicae (Haliday), and Lysiphlebus confusus Tremblay and Eady (Hymenoptera: Braconidae: Aphidiinae) were encountered as the most common parasitoids among 10 identified aphidiine and aphelinid taxa on different citrus species. Hyperparasitoids belonging to the genera Alloxysta, Phaenoglyphis, Asaphes, Pachyneuron, Syrphophagus, and Dendrocerus are reported for the first time emerging from aphids feeding on citrus in Turkey. Among them, Asaphes spp., Pachyneuron spp., and Syrphophagus spp. were recorded as the most common ones. Citrus reticulata Blanco and Citrus limon (L.) Burm. fil. were recorded as main hosts for the aphid parasitoids and their hyperparasitoids. PMID:25480969

  14. Encyrtid parasitoids of soft scale insects: biology, behavior, and their use in biological control.

    Science.gov (United States)

    Kapranas, Apostolos; Tena, Alejandro

    2015-01-01

    Parasitoids of the hymenopterous family Encyrtidae are one of the most important groups of natural enemies of soft scale insects and have been used extensively in biological control. We summarize existing knowledge of the biology, ecology, and behavior of these parasitoids and how it relates to biological control. Soft scale stage/size and phenology are important determinants of host range and host utilization, which are key aspects in understanding how control by these parasitoids is exerted. Furthermore, the nutritional ecology of encyrtids and their physiological interactions with their hosts affect soft scale insect population dynamics. Lastly, the interactions among encyrtids, heteronomous parasitoids, and ants shape parasitoid species complexes and consequently have a direct impact on the biological control of soft scale insects.

  15. How facial attractiveness affects sustained attention.

    Science.gov (United States)

    Li, Jie; Oksama, Lauri; Hyönä, Jukka

    2016-10-01

    The present study investigated whether and how facial attractiveness affects sustained attention. We adopted a multiple-identity tracking paradigm, using attractive and unattractive faces as stimuli. Participants were required to track moving target faces amid distractor faces and report the final location of each target. In Experiment 1, the attractive and unattractive faces differed in both the low-level properties (i.e., luminance, contrast, and color saturation) and high-level properties (i.e., physical beauty and age). The results showed that the attractiveness of both the target and distractor faces affected the tracking performance: The attractive target faces were tracked better than the unattractive target faces; when the targets and distractors were both unattractive male faces, the tracking performance was poorer than when they were of different attractiveness. In Experiment 2, the low-level properties of the facial images were equalized. The results showed that the attractive target faces were still tracked better than unattractive targets while the effects related to distractor attractiveness ceased to exist. Taken together, the results indicate that during attentional tracking the high-level properties related to the attractiveness of the target faces can be automatically processed, and then they can facilitate the sustained attention on the attractive targets, either with or without the supplement of low-level properties. On the other hand, only low-level properties of the distractor faces can be processed. When the distractors share similar low-level properties with the targets, they can be grouped together, so that it would be more difficult to sustain attention on the individual targets. PMID:27347672

  16. Host size and spatiotemporal patterns mediate the coexistence of specialist parasitoids.

    Science.gov (United States)

    Pekas, Apostolos; Tena, Alejandro; Harvey, Jeffrey A; Garcia-Mari, Ferran; Frago, Enric

    2016-05-01

    Many insect parasitoids are highly specialized and thus develop on only one or a few related host species, yet some hosts are attacked by many different parasitoid species in nature. For this reason, they have been often used to examine the consequences of competitive interactions. Hosts represent limited resources for larval parasitoid development and thus one competitor usually excludes all others. Although parasitoid competition has been debated and studied over the past several decades, understanding the factors that allow for coexistence among species sharing the same host in the field remains elusive. Parasitoids may be able to coexist on the same host species if they partition host resources according to size, age, or stage, or if their dynamics vary at spatial and temporal scales. One area that has thus far received little experimental attention is if competition can alter host usage strategies in parasitoids that in the absence of competitors attack hosts of the same size in the field. Here, we test this hypothesis with two parasitoid species in the genus Aphytis, both of which are specialized on the citrus pest California red scale Aonidiella aurantii. These parasitoids prefer large scales as hosts and yet coexist in sympatry in eastern parts of Spain. Parasitoids and hosts were sampled in 12 replicated orange groves. When host exploitation by the stronger competitor, A. melinus, was high the poorer competitor, A. chrysomphali, changed its foraging strategy to prefer alternative plant substrates where it parasitized hosts of smaller size. Consequently, the inferior parasitoid species shifted both its habitat and host size as a result of competition. Our results suggest that density-dependent size-mediated asymmetric competition is the likely mechanism allowing for the coexistence of these two species, and that the use of suboptimal (small) hosts can be advantageous under conditions imposed by competition where survival in higher quality larger hosts may

  17. Physical attractiveness and personality development.

    Science.gov (United States)

    Shea, J; Crossman, S M; Adams, G R

    1978-05-01

    A test of the relationship between physical attractiveness and ego development was completed through an interview study of 294 men and women college students. Ss responded to personality measures assessing identity formation, locus of control, and ego functioning and were rated on facial attractiveness and body form scales. Contrary to the physical attractiveness stereotype, attractive and unattractive Ss did not differ in their personality styles. PMID:650605

  18. Physical attractiveness and personality development.

    Science.gov (United States)

    Shea, J; Crossman, S M; Adams, G R

    1978-05-01

    A test of the relationship between physical attractiveness and ego development was completed through an interview study of 294 men and women college students. Ss responded to personality measures assessing identity formation, locus of control, and ego functioning and were rated on facial attractiveness and body form scales. Contrary to the physical attractiveness stereotype, attractive and unattractive Ss did not differ in their personality styles.

  19. Lack of phenotypic and evolutionary cross-resistance against parasitoids and pathogens in Drosophila melanogaster.

    Directory of Open Access Journals (Sweden)

    Alex R Kraaijeveld

    Full Text Available BACKGROUND: When organisms are attacked by multiple natural enemies, the evolution of a resistance mechanism to one natural enemy will be influenced by the degree of cross-resistance to another natural enemy. Cross-resistance can be positive, when a resistance mechanism against one natural enemy also offers resistance to another; or negative, in the form of a trade-off, when an increase in resistance against one natural enemy results in a decrease in resistance against another. Using Drosophila melanogaster, an important model system for the evolution of invertebrate immunity, we test for the existence of cross-resistance against parasites and pathogens, at both a phenotypic and evolutionary level. METHODS: We used a field strain of D. melanogaster to test whether surviving parasitism by the parasitoid Asobara tabida has an effect on the resistance against Beauveria bassiana, an entomopathogenic fungus; and whether infection with the microsporidian Tubulinosema kingi has an effect on the resistance against A. tabida. We used lines selected for increased resistance to A. tabida to test whether increased parasitoid resistance has an effect on resistance against B. bassiana and T. kingi. We used lines selected for increased tolerance against B. bassiana to test whether increased fungal resistance has an effect on resistance against A. tabida. RESULTS/CONCLUSIONS: We found no positive cross-resistance or trade-offs in the resistance to parasites and pathogens. This is an important finding, given the use of D. melanogaster as a model system for the evolution of invertebrate immunity. The lack of any cross-resistance to parasites and pathogens, at both the phenotypic and the evolutionary level, suggests that evolution of resistance against one class of natural enemies is largely independent of evolution of resistance against the other.

  20. Perceived Attractiveness and Classroom Interactions

    Science.gov (United States)

    Algozzine, Bob

    1977-01-01

    Adams and Cohen (1974) demonstrated that facial attractiveness was a salient factor in differential student-teacher interactions. This research investigates further the interaction between teachers and children perceived to be attractive or unattractive by those teachers. It was hypothesized that attractive children would exhibit more "positive,"…

  1. Communication and Culture: Interpersonal Attraction.

    Science.gov (United States)

    Brown, Lydia Ledesma; Emry, Robert A.

    Cultural differences in interpersonal attraction were studied using 93 black, 112 Chicano, and 112 white college students who completed 40 Likert-type rating scales for each of four concepts of attraction (intimate, friendship, acquaintance, and stranger attraction). When a factor solution was generated, differences were noted in the amount of…

  2. The Role of Attractiveness and Aggression in High School Popularity

    Science.gov (United States)

    Borch, Casey; Hyde, Allen; Cillessen, Antonius H. N.

    2011-01-01

    This study examines the effects of physical attractiveness and aggression on popularity among high school students. Previous work has found positive relationships between aggression and popularity and physical attractiveness and popularity. The current study goes beyond this work by examining the interactive effects of physical attractiveness and…

  3. 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.

  4. Apparent Acquired Resistance by a Weevil to Its Parasitoid Is Influenced by Host Plant.

    Science.gov (United States)

    Goldson, Stephen L; Tomasetto, Federico

    2016-01-01

    Field parasitism rates of the Argentine stem weevil Listronotus bonariensis (Kuschel; Coleoptera: Curculionidae) by Microctonus hyperodae Loan (Hymenoptera: Braconidae) are known to vary according to different host Lolium species that also differ in ploidy. To further investigate this, a laboratory study was conducted to examine parasitism rates on tetraploid Italian Lolium multiflorum, diploid Lolium perenne and diploid hybrid L. perenne ×L. multiflorum; none of which were infected by Epichloë endophyte. At the same time, the opportunity was taken to compare the results of this study with observations made during extensive laboratory-based research and parasitoid-rearing in the 1990s using the same host plant species. This made it possible to determine whether there has been any change in weevil susceptibility to the parasitoid over a 20 year period when in the presence of the tetraploid Italian, diploid perennial and hybrid host grasses that were commonly in use in the 1990's. The incidence of parasitism in cages, in the presence of these three grasses mirrored what has recently been observed in the field. When caged, weevil parasitism rates in the presence of a tetraploid Italian ryegrass host were significantly higher (75%) than rates that occurred in the presence of either the diploid perennial (46%) or the diploid hybrid (52%) grass, which were not significantly different from each other. This is very different to laboratory parasitism rates in the 1990s when in the presence of both of the latter grasses high rates of parasitism (c. 75%) were recorded. These high rates are typical of those still found in weevils in the presence of both field and caged tetraploid Italian grasses. In contrast, the abrupt decline in weevil parasitism rates points to the possibility of evolved resistance by the weevil to the parasitoid in the diploid and hybrid grasses, but not so in the tetraploid. The orientation of plants in the laboratory cages had no significant effect on

  5. The effects of waist-to-hip ratio and body weight on male judgements of female physical attractiveness, wife desirability, and health, both within and between cultures.

    OpenAIRE

    McLean, Julia

    2007-01-01

    Evolutionary theories maintain that female physical attractiveness has evolved to honestly signal health and reproductive potential. Both a low waist-to-hip ratio (WHR) and a critical range of body weight have received considerable attention in this respect. As a result these cues should be universally utilised by males when evaluating female attractiveness. However, a lack of cross-cultural uniformity in these male judgements has led some researchers to reject this theory and ...

  6. Hymenopteran Parasitoids Diversity Associated with Organic and Coventional Agroecosystems in West Sumatera, Indonesia

    Directory of Open Access Journals (Sweden)

    Yaherwandi Yaherwandi

    2014-01-01

    Full Text Available The use of pesticides in agricultural ecosystems does not only cause environmental pollution, but also  impovert  diversity of natural enemies such as parasitoids and predators as well as causes the emergence of pests resistance to pesticides. The study was focused to identify and compare the abundance, diversity and evenness of Hymenopteran parasitoid species  in organic and conventional agroecosystems. This research was conducted in several organic and conventional vegetable agroecosystems in West Sumatera. The tools used for the collection of insects were farmcop, sweep net and yellow pan traps. A total of 717 individuals of Hymenopteran parasitoids belonging to 21 families and 131 species were recorded during the study. A total of 533 individuals collected in organic agroecosystem consisted of 20 families and 85 species of Hymenopteran parasitoids, whereas in conventional agroecosystems there were 184 individuals collected cosisted of 13 families and 46 species of Hymenopteran parasitoids. This study also demonstrated a strong relationship between crops and Hymenopteran parasitoid composition. Species diversity and evenness of Hymenopteran parasitoids were higher in organic than in conventional agroecosystems.

  7. The specificity of herbivore-induced plant volatiles in attracting herbivore enemies.

    Science.gov (United States)

    Clavijo McCormick, Andrea; Unsicker, Sybille B; Gershenzon, Jonathan

    2012-05-01

    Plants respond to herbivore attack by emitting complex mixtures of volatile compounds that attract herbivore enemies, both predators and parasitoids. Here, we explore whether these mixtures provide significant value as information cues in herbivore enemy attraction. Our survey indicates that blends of volatiles released from damaged plants are frequently specific depending on the type of herbivore and its age, abundance and feeding guild. The sensory perception of plant volatiles by herbivore enemies is also specific, according to the latest evidence from studies of insect olfaction. Thus, enemies do exploit the detailed information provided by plant volatile mixtures in searching for their prey or hosts, but this varies with the diet breadth of the enemy.

  8. The effect of the attractive well of the potential energy surface for Ne-HCl on rotationally inelastic partial wave cross sections

    Institute of Scientific and Technical Information of China (English)

    Yu Chun-Ri; Shi Shou-Hua; Wang Rong-Kai; Yang Xiang-Dong

    2007-01-01

    An interaction potential of the Ne-HCl van der Waals complex is obtained by utilizing the Huxley analytic potential function to fit the accurate interaction energy data, which have been computed at the coupled cluster singles and doubles including connected triple excitations level and with the augmented correlation consistent polarized valence quintuple zeta basis set extended with a set of 3s3p2d1f1g mid-bond functions [CCSD (T)/aug-cc-pV5Z-33211]. The close coupling calculation of state-to-state partial cross sections for collision of Ne with HCl is first performed by employing the fitted interaction potential. This calculation is performed at the incident energies: 40, 60, 75 and 100 meV, separately. The effects of the long-range attractive and the short-range anisotropic interactions on the inelastic state-to-state partial cross sections are discussed in detail. Two maxima are present in the rotationally inelastic partial cross sections and they originate from different mechanisms.

  9. Evaluation of the attractive effect of coloured sticky traps for Aleurocanthus spiniferus (Quaintance and its monitoring method in tea garden in China

    Directory of Open Access Journals (Sweden)

    Y. Wang

    2015-12-01

    Full Text Available Aleurocanthus spiniferus (Quaintance, namely tea spiny whitefly (TSW, belongs to the family Aleyrodidae in the order Homoptera, widespread in tea trees and fruit trees in many countries or regions. In this study, the preference of TSW for different colours was evaluated in tea gardens. Yellow was the colour most preferred by TSW, followed by pink, red, white and other colours. The controlling technologies about the number of sticky traps in a certain area of tea garden and the height of sticky traps above tea canopy were also evaluated, the results indicated that the attractive effect of 20 traps/667 m2 of trials area and the height of 10 cm above tea canopy were significantly higher than others treatments. In addition, more TSW was caught at 11:00-15:00, followed by 7:00-11:00, and 15:00-19:00 in a daytime; higher activity level of male adults was at 7:00-11:00 and 11:00-15:00 in day time (95.13% and 94.97% of caught TSW, indicating a higher activity level for male adult.

  10. 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

  11. 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)

  12. A taxonomic investigation on egg parasitoid, Anagrus of rice planthopper in Zhejiang Province

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    @@Exploitation and utilization of beneficial arthropods viz. insects and spiders to regulate pest populations has a good prospect in China. The role of non_rice habitats in maintaining the population of natural enemies of the brown planthopper, Nilaparvata lugens (stal) (Hemiptera: Delphacidae) has been investigated in Zhejiang Province since 1994. The work focused primarily on the egg parasitoids genus Anagrus (Hymenoptera: Mymaridae). Plants laden with eggs of the brown planthopper were exposed 2 d every week in the rice fields and grassy areas dominated by Digitaria spp. Then, the plants were retrieved and brought back to the laboratory for parasitoid rearing. Newly emerged parasitoids were preserved in alcohol solution for further identification.

  13. Comments on plant-herbivore-parasitoid interactions in two cerrado areas of Southern Brazil

    Directory of Open Access Journals (Sweden)

    Astrid Caldas

    1996-01-01

    Full Text Available This work describes some interactions between lepidopteran larvae and braconid parasitoids on a group of plants at two sites. There was no significant difference in parasitoid diversity between the sites (Shannon index, p<0.05, and similarity was 62.5%, estimated through Sorensen's index. The diversity of hosts was also not different (p<0.05, but the similarity of host diversity was only 28.5%. This suggests that the parasitoids have strategies for maintaining similar reproduction rates, population densities and communities in areas with different potential hosts.

  14. A review of hymenopterous parasitoid guilds attacking Anastrepha spp. and Ceratitis capitata (Diptera: Tephritidae) in Argentina

    International Nuclear Information System (INIS)

    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)

  15. Uncovering Cryptic Parasitoid Diversity in Horismenus (Chalcidoidea, Eulophidae.

    Directory of Open Access Journals (Sweden)

    Sarah G Kenyon

    Full Text Available Horismenus parasitoids are an abundant and understudied group of eulophid wasps found mainly in the New World. Recent surveys based on morphological analyses in Costa Rica have quadrupled the number of named taxa, with more than 400 species described so far. This recent revision suggests that there is still a vast number of unknown species to be identified. As Horismenus wasps have been widely described as parasitoids of insect pests associated with crop plants, it is of high importance to properly establish the extant diversity of the genus, in order to provide biological control practitioners with an exhaustive catalog of putative control agents. In this study, we first collected Horismenus wasps from wild Phaseolus bean seeds in Central Mexico and Arizona to assess the genetic relatedness of three morphologically distinct species with overlapping host and geographical ranges. Sequence data from two nuclear and two mitochondrial gene regions uncovered three cryptic species within each of the three focal species (i.e., H. missouriensis, H. depressus and H. butcheri. The monophyly of each cryptic group is statistically supported (except in two of them represented by one single tip in which monophyly cannot be tested. The phylogenetic reconstruction is discussed with respect to differences between gene regions as well as likely reasons for the differences in variability between species.

  16. Physical Attractiveness Stereotypes about Marriage: Attractiveness Matching Is Good.

    Science.gov (United States)

    Sussman, Steve; And Others

    Previous research on physical attractiveness stereotypes about marriage have used stimulus individuals in isolation. To examine these attractiveness stereotypes using couples as targets, 72 college students (36 females, 36 males) rated eight photographs of four male-female couple types. Members of each couple were either matched (attractive…

  17. Species Diversity in the Parasitoid Genus Asobara (Hymenoptera: Braconidae from the Native Area of the Fruit Fly Pest Drosophila suzukii (Diptera: Drosophilidae.

    Directory of Open Access Journals (Sweden)

    Emilio Guerrieri

    Full Text Available Drosophila suzukii (Matsumura, commonly known as Spotted Wing Drosophila (SWD, is a worldwide serious economic threat to the production of berries and stone fruits. The chemical control widely used against this pest is often not able to preventing yield losses because wild flora offers an abundance of fruits to D. suzukii where the pest is able to reproduce and from where it recolonizes neighbouring cultivated fields. Alternatively, within Integrated Pest Management protocols for D. suzukii, biological control could play a key role by reducing its populations particularly in non-cultivated habitats, thus increasing the effectiveness and reducing the side negative effects of other management strategies. Because of the scarcity and of the low efficiency of autochthonous parasitoids in the new invaded territories, in the last few years, a number of surveys started in the native area of D. suzukii to find parasitoid species to be evaluated in quarantine structures and eventually released in the field, following a classical biological control approach. This paper reports the results of these surveys carried out in South Korea and for the first time in China. Among the parasitoids collected, those belonging to the genus Asobara Foerster resulted dominant both by number and species diversity. By combining morphological characters and the mitochondrial COI gene as a molecular marker, we identified seven species of Asobara, of which two associated with D. suzukii, namely A. japonica and A leveri, and five new to science, namely Asobara brevicauda, A. elongata, A mesocauda, A unicolorata, A. triangulata. Our findings offer new opportunity to find effective parasitoids to be introduced in classical biological control programmes in the territories recently invaded by D. suzukii.

  18. 间作绿肥对茶园寄生蜂和假眼小绿叶蝉的影响%Effects of Green manure intercroppinG on parasitoids and Wmpoasca vitis(GÖthe)in tea pLantations

    Institute of Scientific and Technical Information of China (English)

    江道检; 许丽艳; 程章平

    2014-01-01

    2012年5月至11月在福州闽侯洋里金田农场生态茶园,对间作白三叶、印度豇豆和生产茶园3种不同茶园的寄生蜂群落结构和假眼小绿叶蝉及其卵缨小蜂消长动态进行调查和分析。3种不同茶园的寄生蜂群落结构基本相似,间作2种绿肥提高了寄生蜂物种数、个体数和多样性指数,但对均匀性指数和优势集中性指数没有影响。3种不同茶园的假眼小绿叶蝉数量消长趋势一致,其高峰期都在7月底和10月底-11月,但生产茶园的小绿叶蝉个体数都显著低于2种间作绿肥茶园,这可能与生产茶园的农药使用有关。3种不同茶园茶梢内的小绿叶蝉着卵量消长趋势基本一致,都有2个着卵高峰期(6月下旬和11月上旬),第二高峰期梢内的叶蝉平均着卵量显著高于第一高峰期;整个调查期间,生产茶园梢内的叶蝉着卵量均低于2种间作茶园,这可能也是生产茶园的农药使用造成的。3种不同茶园茶梢内的叶蝉卵寄生率在调查期间内总体呈上升趋势,并于11月19日达到65.19%-76.52%。%The popuLation dynamics of parasitoids and the green Leafhopper,Empoasca vitis( GÖthe)were investigated and anaLyzed in two tea pLantations with intercropping of white cLover and Indian cowpea respectiveLy,and in one con-troL tea pLantation without intercropping but with farming practices such as insecticide spray at the Jintian ecoLogicaL tea garden in YangLi,Minhou,Fuzhou,during May to November 2012. In these three types of tea pLantations,the structures of parasitoids communities were simiLar,and two types of intercropping increased the parasitoid species,in-dividuaL number and diversity index,and had no effect on eveness index and dominant concentration index. In three types of tea pLantations,the dynamics of green Leafhopper were paraLLeLed,with two peaks in Late JuLy and earLy No-vember,and with a smaLLer popuLation in the controL p

  19. 5种化合物对家蝇的引诱效果研究%Study on attractive effects of five compounds on Musca domestica

    Institute of Scientific and Technical Information of China (English)

    莫晓畅

    2013-01-01

    目的 了解乳酸、正庚酸、丙烯酸甲酯、三甲基吲哚和二甲基二硫醚5种化合物在不同浓度下对家蝇的引诱效果.方法 将5种化合物用玉米粉稀释成不同浓度,然后将不同浓度的同种化合物分别放在蚊蝇诱捕盒的饵料盘中,在蚊帐内对家蝇成虫进行引诱实验.结果 0.1、1.0 mg/kg的乳酸,0.1、1.0 mg/kg的正庚酸,1000.0 mg/kg的丙烯酸甲酯,1.0、10.0 mg/kg的三甲基吲哚,10.0、100.0 mg/kg的二甲基二硫醚引诱的家蝇数量比对照分别多50.0%和53.0%、210.7%和77.7%、155.1%、81.6%和139.8%、137.3%和168.7%.结论 综合考虑引诱效果和化合物气味,乳酸和正庚酸可作为室内家蝇引诱剂的成分用于家蝇诱杀,丙烯酸甲酯、三甲基吲哚和二甲基二硫醚可作为室外家蝇引诱剂的成分用于家蝇防治.%Objective To investigate the attractive effects of different concentrations of lactic acid,enanthic acid,methacrylate,trimethylindole,and dimethyl disulfide on Musca domestica.Methods Lactic acid,enanthic acid,methacrylate,trimethylindole,and dimethyl disulfide were separately diluted with corn flour to different concentrations,and these compounds were put in the bait trays of mosquito-fly traps.The traps were placed in a mosquito net to capture adult M.domestica.Results Compared with controls,0.1 and 1.0 mg/kg lactic acid led to 50.0% and 53.0% increases in number of captured houseflies,0.1 and 1.0 mg/kg enanthic acid led to 210.7% and 77.7% increases in number of captured houseflies,1000.0 mg/kg methacrylate led to a 155.1% increase in number of captured houseflies,1.0 and 10.0 mg/kg trimethylindole led to 81.6% and 139.8% increases in number of captured houseflies,and 10.0 and 100.0 mg/kg dimethyl disulfide led to 137.3% and 168.7% increases in number of captured houseflies.Conclusion Considering the attractive effect and compound odor,lactic acid and enanthic acid may be used as the components

  20. Esthetic effect of the buccal corridor size and amount of tooth-gingival display on smile attractiveness in two student population

    Directory of Open Access Journals (Sweden)

    Hooman Zarif Najafi

    2015-05-01

    Full Text Available 3- Dentist   Background and Aims: An attractive, well-balanced smile is a paramount treatment objective of the modern orthodontic therapy. The purpose of this study was to determine the effects of the buccal corridor size and tooth-gingival display on the smile esthetics as perceived by two groups of the students.   Materials and Methods: A colored image of a woman frontal posed smile was selected. The image was altered digitally to produce different buccal corridor sizes (6%, 12.5% and 20% and different tooth-gingival displays (maxillary central incisors and 2 mm of gingival, maxillary central incisors and dental papilla and 80% of the maxillary central incisors. The different buccal corridor sizes and tooth-gingival displays were combined to produce 9 images. These altered images were rated by 120 medical and dental students using Visual Analogue Scale (VAS. Data were analyzed using Mann-Whitney test, Pairwise comparison LSD test, Repeated measure MANOVA and ICC (Intraclass Correlation Coefficient.   Results: The smile which had the buccal corridor size of 12.5% and complete incisor display without gingival display received the highest rates among the nine smile images in the dental students group. But in the medical students group the smile with the buccal corridor size of 12.5% and 2 mm gingival display, received the highest rates among the nine smile images. There was no significant difference in judging between the male and female raters for the both groups (P>0.05. The dental students were more critical about the increasing of the gingival display.   Conclusion: In the treatment procedure that may lead to the combination of wide buccal corridor and more tooth-gingival show, more caution should be considered.

  1. Estimating geocenter motion and barystatic sea-level variability from GRACE observations with explicit consideration of self-attraction and loading effects

    Science.gov (United States)

    Bergmann-Wolf, Inga; Dobslaw, Henryk

    2016-04-01

    Estimating global barystatic sea-level variations from monthly mean gravity fields delivered by the Gravity Recovery and Climate Experiment (GRACE) satellite mission requires additional information about geocenter motion. These variations are not available directly due to the mission implementation in the CM-frame and are represented by the degree-1 terms of the spherical harmonics expansion. Global degree-1 estimates can be determined with the method of Swenson et al. (2008) from ocean mass variability, the geometry of the global land-sea distribution, and GRACE data of higher degrees and orders. Consequently, a recursive relation between the derivation of ocean mass variations from GRACE data and the introduction of geocenter motion into GRACE data exists. In this contribution, we will present a recent improvement to the processing strategy described in Bergmann-Wolf et al. (2014) by introducing a non-homogeneous distribution of global ocean mass variations in the geocenter motion determination strategy, which is due to the effects of loading and self-attraction induced by mass redistributions at the surface. A comparison of different GRACE-based oceanographic products (barystatic signal for both the global oceans and individual basins; barotropic transport variations of major ocean currents) with degree-1 terms estimated with a homogeneous and non-homogeneous ocean mass representation will be discussed, and differences in noise levels in most recent GRACE solutions from GFZ (RL05a), CSR, and JPL (both RL05) and their consequences for the application of this method will be discussed. Swenson, S., D. Chambers and J. Wahr (2008), Estimating geocenter variations from a combination of GRACE and ocean model output, J. Geophys. Res., 113, B08410 Bergmann-Wolf, I., L. Zhang and H. Dobslaw (2014), Global Eustatic Sea-Level Variations for the Approximation of Geocenter Motion from GRACE, J. Geod. Sci., 4, 37-48

  2. Ordinal Position, Approval Motivation, and Interpersonal Attraction

    Science.gov (United States)

    Nowicki, Stephen, Jr.

    1971-01-01

    Results of the study suggest that birth-order effects might be included within the wider framework of approval-dependency theory. Females tend to account for a significant share of birth-order effects. More particularly, firstborn females accounted for much of the differences in expressed attraction as well as need for social approval. (Author)

  3. Physical Attractiveness and Courtship Progress.

    Science.gov (United States)

    White, Gregory L.

    1980-01-01

    Among college students who were casual or serious daters, greater relative attractiveness was positively correlated with greater relative availability of opposite-sexed friends and negatively correlated with worrying about partner's potential involvement with others. A 9-month follow-up revealed that similarity of attractiveness was predictive of…

  4. Physical Attractiveness and Interpersonal Influence

    Science.gov (United States)

    Dion, Karen K.; Stein, Steven

    1978-01-01

    Examines the hypothesis that attractive individuals should be more successful with opposite-sex peers but less successful with same-sex peers than unattractive individuals. Also investigates the influence strategies employed by persons differing in attractiveness since nothing is currently known about the actual behavior exhibited by attractive…

  5. Physical attractiveness stereotype and memory.

    Science.gov (United States)

    Rohner, Jean-Christophe; Rasmussen, Anders

    2011-08-01

    Three experiments examined explicit and implicit memory for information that is congruent with the physical attractiveness stereotype (i.e. attractive-positive and unattractive-negative) and information that is incongruent with the physical attractiveness stereotype (i.e. attractive-negative and unattractive-positive). Measures of explicit recognition sensitivity and implicit discriminability revealed a memorial advantage for congruent compared to incongruent information, as evident from hit and false alarm rates and reaction times, respectively. Measures of explicit memory showed a recognition bias toward congruent compared to incongruent information, where participants tended to call congruent information old, independently of whether the information had been shown previously or not. This recognition bias was unrelated to reports of subjective confidence in retrieval. The present findings shed light on the cognitive mechanisms that might mediate discriminatory behavior towards physically attractive and physically unattractive individuals. PMID:21255024

  6. Physical attractiveness stereotype and memory.

    Science.gov (United States)

    Rohner, Jean-Christophe; Rasmussen, Anders

    2011-08-01

    Three experiments examined explicit and implicit memory for information that is congruent with the physical attractiveness stereotype (i.e. attractive-positive and unattractive-negative) and information that is incongruent with the physical attractiveness stereotype (i.e. attractive-negative and unattractive-positive). Measures of explicit recognition sensitivity and implicit discriminability revealed a memorial advantage for congruent compared to incongruent information, as evident from hit and false alarm rates and reaction times, respectively. Measures of explicit memory showed a recognition bias toward congruent compared to incongruent information, where participants tended to call congruent information old, independently of whether the information had been shown previously or not. This recognition bias was unrelated to reports of subjective confidence in retrieval. The present findings shed light on the cognitive mechanisms that might mediate discriminatory behavior towards physically attractive and physically unattractive individuals.

  7. Toxicity of pesticides to Tamarixia radiata, a parasitoid of the Asian citrus psyllid

    Science.gov (United States)

    Sixteen pesticides including two fungicides were evaluated for toxicity to adult Tamarixia radiata (Waterston) (Hymenoptera: Eulophidae), a parasitoid of the Asian citrus psyllid, Diaphorina citri Kuwayama (Hemiptera: Psyllidae). Percentage mortality data were evaluated to generally assess IPM-com...

  8. Insects Can Count: Sensory Basis of Host Discrimination in Parasitoid Wasps Revealed

    NARCIS (Netherlands)

    Ruschioni, S.; Loon, van J.J.A.; Smid, H.M.; Lenteren, van J.C.

    2015-01-01

    The solitary parasitoid Leptopilina heterotoma is one of the best studied organisms concerning the ecology, behaviour and physiology of host discrimination. Behavioural evidence shows that L. heterotoma uses its ovipositor to discriminate not only between parasitized and unparasitized Drosophila mel

  9. Beneficial insects attracted to native flowering buckwheats (Eriogonum Michx) in central Washington.

    Science.gov (United States)

    James, David G; Seymour, Lorraine; Lauby, Gerry; Buckley, Katie

    2014-08-01

    Native plant and beneficial insect associations are relatively unstudied yet are important in native habitat restoration programs aimed at improving conservation biological control in perennial crops such as wine grapes. Beneficial insects (predators, parasitoids, pollinators) attracted to 10 species of flowering native wild buckwheat (Eriogonum spp.) in central Washington were identified and counted on transparent sticky traps. Combining all categories of beneficial insects, the mean number per trap ranged from 48.5 (Eriogonum umbellatum) to 167.7 (Eriogonum elatum). Three Eriogonum spp. (E. elatum, Eriogonum compositum, and Eriogonum niveum) attracted significantly more beneficial insects than the lowest-ranked species. E. niveum attracted greatest numbers of bees and parasitic wasps, and E. elatum was highly attractive to predatory true bugs and beneficial flies. Blooming periods of Eriogonum spp. extended from mid April to the end of September. This study demonstrates the attraction of beneficial insects to native flowering buckwheats and suggests their potential as a component of habitat restoration strategies to improve and sustain conservation biological control in Washington viticulture. PMID:24960157

  10. Kairomonal effect of sex pheromone components of two lepidopteran olive pests on Trichogramma wasps

    Institute of Scientific and Technical Information of China (English)

    Panos Milonas; Basilios E. Mazomenos; Maria A. Konstantopoulou

    2009-01-01

    Egg parasitoids are known to use a wide range of chemicals, emitted by plants, host eggs or adults, for host selection. The effect of the sex pheromone components of the lepidopteran olive pests Prays oleae (Lepidoptera: Yponomeutidae) and Palpita unionalis (Lepidoptera: Pyralidae) was studied under laboratory conditions, on the foraging behaviour of the egg parasitoid Trichogramma oleae (Hymenoptera: Trichogrammatidae). The re-sponse of T. oleae wasps to (Z)-7-tetradecenal and (E)-11-hexadecenal, major sex phero-mone components of P. oleae and P. unionalis respectively, depended on the dose of the pheromone used in a Y-tube olfactometer bioassay. (E)-11-hexadecenal elicited maximum attraction (70%) at a dose of 1 μg, while a dose of 100 μg (Z)-7-tetradecenal attracted 80% of the tested wasps. (E)-11-hexadecenyl acetate, the second sex pheromone component of P. unionalis, and the binary blend of (E)-11-hexadecenyl acetate: (E)-11-hexadecenal (7:3) were not attractive at these doses. The results of this research are discussed in view that they may he considered as alternatives in the biological control of these pests.

  11. Toxicity of Three Insecticides to Lysiphlebus fabarum, a Parasitoid of the Black Bean Aphid, Aphis fabae

    OpenAIRE

    Sabahi, Qodratollah; Rasekh, Arash; Michaud, J.P.

    2011-01-01

    The toxicity of three insecticides to Lysiphlebus fabarum (Marshall) (Hymenoptera: Braconidae: Aphidiinae), a parasitoid of Aphis fabae Scopoli (Hemiptera: Aphididae), was investigated using IOBC/wprs protocols. Abamectin 1.8 EC, imidacloprid 350 SC, and pymetrozine 25 WP were tested under laboratory conditions at recommended field rates. Immature stages of the parasitoid were exposed to materials by briefly dipping mummified aphids into insecticide solutions/suspensions or water (controls). ...

  12. Impact of Two Ant Species on Egg Parasitoids Released as Part of a Biological Control Program

    OpenAIRE

    Kergunteuil, Alan; Basso, César; Pintureau, Bernard

    2013-01-01

    Biological control using Trichogramma pretiosum Riley (Hymenoptera: Trichogrammatidae), an egg parasitoid wasp, was tested in Uruguay to reduce populations of lepidopteran pests on soybeans. It was observed that the commercial parasitoid dispensers, which were made of cardboard, were vulnerable to small predators that succeeded in entering and emptying the containers of all the eggs parasitized by T. pretiosum. Observations in a soybean crop showed that the only small, common predators presen...

  13. Host–parasitoid spatial ecology: a plea for a landscape-level synthesis

    OpenAIRE

    James T Cronin; Reeve, John D.

    2005-01-01

    A growing body of literature points to a large-scale research approach as essential for understanding population and community ecology. Many of our advances regarding the spatial ecology of predators and prey can be attributed to research with insect parasitoids and their hosts. In this review, we focus on the progress that has been made in the study of the movement and population dynamics of hosts and their parasitoids in heterogeneous landscapes, and how this research approach may be benefi...

  14. Shifting preference between oviposition vs. host-feeding under changing host densities in two aphelinid parasitoids.

    Directory of Open Access Journals (Sweden)

    Nian-Wan Yang

    Full Text Available 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 feeding and oviposition on two whitefly parasitoids under varying host densities. Females of two aphelinid parasitoids, Eretmocerus hayati and Encarsia sophia were exposed to nine different densities of their whitefly host, Bemisia tabaci, in single-instar tests to identify their functional response. Mixed-instar host choice tests were also conducted by exposing whiteflies at four densities to the parasitoids. We hypothesized that the parasitoid females can detect different host densities, and decide on oviposition vs. host-feeding accordingly. The results showed that both Er. hayati and En. sophia females tended to increase both oviposition and host-feeding with increased host density within a certain range. Oviposition reached a plateau at lower host density than host-feeding in Er. hayati, while En. sophia reached its oviposition plateau at higher densities. At low densities, Er. hayati parasitized most on first and second (the optimal ones, and fed most on third nymphal instars (the suboptimal one of the whitefly host as theory predicts, while at high densities, both parasitism and host-feeding occurred on first and second instars which are preferred for oviposition. En. sophia parasitized most on third and fourth (the optimal ones, while fed on first instars (the suboptimal one at low densities, and utilized third and fourth instars for both at high densities. In conclusion, oviposition vs. host-feeding strategy of parasitoid females was found to vary at different host densities. The balance between reserving optimal hosts for oviposition or using them for host-feeding depended on parasitoid life history and the availability of host resources.

  15. Hymenopteran Parasitoids Diversity Associated with Organic and Coventional Agroecosystems in West Sumatera, Indonesia

    OpenAIRE

    Yaherwandi Yaherwandi; Hidrayani Hidrayani

    2014-01-01

    The use of pesticides in agricultural ecosystems does not only cause environmental pollution, but also  impovert  diversity of natural enemies such as parasitoids and predators as well as causes the emergence of pests resistance to pesticides. The study was focused to identify and compare the abundance, diversity and evenness of Hymenopteran parasitoid species  in organic and conventional agroecosystems. This research was conducted in several organic and conventional vegetable agroecosystems ...

  16. Recognition bias and the physical attractiveness stereotype.

    Science.gov (United States)

    Rohner, Jean-Christophe; Rasmussen, Anders

    2012-06-01

    Previous studies have found a recognition bias for information consistent with the physical attractiveness stereotype (PAS), in which participants believe that they remember that attractive individuals have positive qualities and that unattractive individuals have negative qualities, regardless of what information actually occurred. The purpose of this research was to examine whether recognition bias for PAS congruent information is replicable and invariant across a variety of conditions (i.e. generalizable). The effects of nine different moderator variables were examined in two experiments. With a few exceptions, the effect of PAS congruence on recognition bias was independent of the moderator variables. The results suggest that the tendency to believe that one remembers information consistent with the physical attractiveness stereotype is a robust phenomenon. PMID:22416805

  17. Recognition bias and the physical attractiveness stereotype.

    Science.gov (United States)

    Rohner, Jean-Christophe; Rasmussen, Anders

    2012-06-01

    Previous studies have found a recognition bias for information consistent with the physical attractiveness stereotype (PAS), in which participants believe that they remember that attractive individuals have positive qualities and that unattractive individuals have negative qualities, regardless of what information actually occurred. The purpose of this research was to examine whether recognition bias for PAS congruent information is replicable and invariant across a variety of conditions (i.e. generalizable). The effects of nine different moderator variables were examined in two experiments. With a few exceptions, the effect of PAS congruence on recognition bias was independent of the moderator variables. The results suggest that the tendency to believe that one remembers information consistent with the physical attractiveness stereotype is a robust phenomenon.

  18. O efeito da infidelidade sobre a atratividade facial de homens e mulheres The effect of infidelity on male and female facial attractiveness

    Directory of Open Access Journals (Sweden)

    Rosana Suemi Tokumaru

    2010-04-01

    Full Text Available Os estudos da atratividade e da seleção de parceiros têm recebido atenção especial dentro da perspectiva da Psicologia Evolucionista, mostrando influências tanto de fatores físicos quanto de fatores não-físicos. Neste estudo, utilizou-se de fotografias da face de homens e mulheres, pré-julgados como medianamente atraentes, desconhecidos dos participantes, associadas a uma história neutra ou que envolvia comportamento de infidelidade, para avaliar a influência de informação sobre o comportamento de infidelidade na avaliação da atratividade de indivíduos do sexo oposto. Os resultados mostraram diferenças significativas apenas quando as mulheres avaliavam fotografias de homens, atribuindo menor atratividade a homens associados à história de infidelidade. As diferenças entre homens e mulheres podem refletir mecanismos adaptativos para a avaliação da atratividade do sexo oposto relacionados às diferenças nos custos reprodutivos. Esses resultados são discutidos sob a perspectiva da Psicologia Evolucionista.Studies of attractiveness and mate selection have received special attention within the Evolutionary Psychology perspective, showing influences from both physical and non-physical factors. In the present study, we used photographs showing faces of men and women, pre-judged as median attractive people, unknown to the participants, associated with neutral stories or stories involving infidelity behavior, to investigate the influence of information about infidelity behavior on the evaluation of attractiveness of opposite sex individuals. Results showed significant differences only when women evaluated men's photographs, attributing lower attractiveness to men associated with a story of infidelity. The sex differences found may represent adapted mechanisms to evaluate opposite sex attractiveness related to differences in reproductive costs. These results are discussed mainly under the Evolutionary Psychology perspective.

  19. Preliminary experiments on the mass-trapping and releasing of the parasitoid (Psyttalia concolor Szepl.) to control the olive fruit fly (Bactrocera oleae Gmel.)

    International Nuclear Information System (INIS)

    Full text: This experiment was conducted in an olive orchard containing 2,500 olive trees in Goekceada, 2002. Eco-traps (Vioryl Firm, Athens, Greece) were utilised for mass-trapping olive fly. In addition, Psyttalia concolor Szepl, which is one of the most effective parasitoids of olive fruit fly, were mass-reared on Mediterranean fruit fly, Ceratitis capitata (Wied.) larvae under laboratory conditions and were released throughout the natural population. Olive fruit fly populations in the experimental and control area were measured by means of McPhail and yellow sticky pheromone traps. A total of 2,000 Eco-traps were distributed in the experimental area before the first punctures were observed. Parasitoid releases were started by the time of the first punctures and continued in paralell to the increasing adult population. Fruit samples that were taken before each release and at harvest were counted. Wormy fruits were taken into culture to observe parasitoid emergence. As for the result of the study in the experimental area the efficiency of the combined technique was 79.32%, whereas the damage rate in control area was 87.60%. (author)

  20. Eurytoma serratulae and E. robusta (Hymenoptera, Eurytomidae: complementary host exploitation strategies of coexisting parasitoids and their impact on the host Urophora cardui

    Directory of Open Access Journals (Sweden)

    Helmut Zwölfer

    2015-03-01

    Full Text Available Our study investigates the host exploitation strategies of Eurytoma serratulae and E. robusta (Chalcidoidea, Eurytomidae, two parasitoid species that co-occur in gall populations of the tephritid Urophora cardui on Cirsium spp. The endoparasitoid E. serratulae detects the host larvae before an externally visible gall is formed. It profits from large galls, as its parasitization rate increases with increasing numbers of chambers per gall. Oviposition by the ectoparasitoid E. robusta does not occur until a distinct gall with chambers has been formed. Its parasitization rate reaches highest values in medium-sized galls. Eurytoma robusta is the dominant parasitoid in host populations with low and moderate gall densities, whereas E. serratulae is the superior exploiter of host populations with high gall densities. Within single galls E. robusta is an important hyperparasitoid of E. serratulae, but E. serratulae has no adverse influence on E. robusta. Parasitism by E. serratulae induces host larvae to promote gall growth, an effect that is profitable to both the parasitoid and the remaining host larvae in the gall. Parasitism by E. robusta often leads to smaller galls, as cases of unsuccessful parasitization result in empty gall cells.

  1. Parasitoid Guilds of Agrilus Woodborers (Coleoptera: Buprestidae: Their Diversity and Potential for Use in Biological Control

    Directory of Open Access Journals (Sweden)

    Philip B. Taylor

    2012-01-01

    Full Text Available Literature studies in North America (US and Canada, Europe, and Asia (particularly Russia, China, Japan, and the Korean peninsula were reviewed to identify parasitoid guilds associated with Agrilus woodborers. There are at least 12 species of hymenopteran parasitoids attacking eggs of Agrilus beetles and 56 species (36 genera, attacking Agrilus larvae infesting various host plants in North America, Asia, and Europe. While most of the egg parasitoids (9 species belong to the family Encyrtidae, a majority of the larval parasitoids are members of five families: Braconidae (24 species/11 genera, Eulophidae (8 species/4 genera, Ichneumonidae (10 species/9 genera, and Eupelmidae (6 species/5 genera. The highest rate of Agrilus egg parasitism (>50% was exerted by encyrtid wasps (4 species in North America, Asia, and Europe. In contrast, the highest rate of Agrilus larval parasitism (>50% was caused by species in two genera of braconids: Atanycolus (North America and Spathius (Asia, and one eulophid genus, Tetrastichus (Asia and Europe. Reported rate of Agrilus larval parasitism ichneumonids was frequent in North America, but generally low (<1%. Potential for success in biological control of emerald ash borer (Agrilus planipennis Fairmaire in the USA with North American native parasitoids and old-association Asian parasitoids is discussed.

  2. Conservation of Agroecosystem through Utilization of Parasitoid Diversity: Lesson for Promoting Sustainable Agriculture and Ecosystem Health

    Directory of Open Access Journals (Sweden)

    DAMAYANTI BUCHORI

    2008-12-01

    Full Text Available For many years, agricultural intensification and exploitation has resulted in biodiversity loss and threaten ecosystem functioning. Developing strategies to bridge human needs and ecosystem health for harmonization of ecosystem is a major concern for ecologist and agriculturist. The lack of information on species diversity of natural enemies and how to utilize them with integration of habitat management that can renovate ecological process was the main obstacle. Parasitoids, a group of natural enemies, play a very important role in regulating insect pest population. During the last ten years, we have been working on exploration of parasitoid species richness, how to use it to restore ecosystem functions, and identifying key factors influencing host-parasitoid interaction. Here, we propose a model of habitat management that is capable of maintaining agricultural biodiversity and ecosystem functions. We present data on parasitoid species richness and distribution in Java and Sumatera, their population structure and its impact toward biological control, relationship between habitat complexes and parasitoid community, spatial and temporal dynamic of parasitoid diversity, and food web in agricultural landscape. Implications of our findings toward conservation of agroecosystem are discussed.

  3. Eulophid parasitoids (Hymenoptera: Eulophidae) of the horse chestnut leafminer, Cameraria ohridella (Lepidoptera: Gracillariidae), from İstanbul, Turkey

    OpenAIRE

    CEBECİ, Hacı Hüseyin; Grabenweger, Giselher; Ayberk, Hamit

    2011-01-01

    The eulophid parasitoids (Hymenoptera: Eulophidae) of Cameraria ohridella Deschka and Dimic (Lepidoptera: Gracillariidae) on horse chestnuts (Aesculus hippocastanum L.) in İstanbul were determined for the first time. Horse chestnut leaves infested with leafminers were collected in 2008 and adult parasitoids were obtained in emergence cages in the laboratory. A total of 10 eulophid parasitoid species were identified, 5 of which, namely Cirrospilus viticola (Rondani), Pnigalio mediterraneus (Fe...

  4. High Heels Increase Women's Attractiveness.

    Science.gov (United States)

    Guéguen, Nicolas

    2015-11-01

    Research has found that the appearance of women's apparel helps increase their attractiveness as rated by men and that men care more about physical features in potential opposite-sex mates. However, the effect of sartorial appearance has received little interest from scientists. In a series of studies, the length of women's shoe heels was examined. A woman confederate wearing black shoes with 0, 5, or 9 cm heels asked men for help in various circumstances. In Study 1, she asked men to respond to a short survey on gender equality. In Study 2, the confederate asked men and women to participate in a survey on local food habit consumption. In Study 3, men and women in the street were observed while walking in back of the female confederate who dropped a glove apparently unaware of her loss. It was found that men's helping behavior increased as soon as heel length increased. However, heel length had no effect on women's helping behavior. It was also found that men spontaneously approached women more quickly when they wore high-heeled shoes (Study 4). Change in gait, foot-size judgment, and misattribution of sexiness and sexual intent were used as possible explanations. PMID:25408499

  5. Efeito de doses e de refúgio sobre a seletividade de inseticidas a predadores e parasitóides de pragas de soja Effect of doses and of refuge on the insecticide selectivity to predators and parasitoids of soybean insect pests

    Directory of Open Access Journals (Sweden)

    Ivan Carlos Corso

    1999-09-01

    Full Text Available Com o objetivo de avaliar o impacto sazonal de alguns inseticidas sobre predadores e parasitóides de pragas da cultura da soja, instalou-se um experimento com delineamento de blocos ao acaso, constando de oito tratamentos e três repetições, no campo experimental da Embrapa-Centro Nacional de Pesquisa de Soja, em Londrina, PR. Os tratamentos consistiram de aplicações de inseticidas para o controle da lagarta-da-soja (pulverizados em 21/1/93 e percevejos (4/3/93. A técnica empregada para levantamento da população de insetos foi a do método do choque, que consiste na aplicação de um inseticida de alto impacto sobre a comunidade de insetos presente nas plantas, sua coleta sobre panos estendidos no solo, e sua posterior identificação e contagem em laboratório. A análise da variância revelou não haver diferenças significativas entre as populações de predadores, himenópteros e dípteros encontrados, nos diferentes tratamentos estudados. Também n��o foram verificados os fenômenos de ressurgência de pragas ou o aparecimento de elevadas populações de pragas secundárias.A field experiment was conducted to evaluate seasonal effect of insecticides on predators and parasitoids of soybean insect pests. A randomized block design was used, with three replications, and the experiment was set up in the experimental station of the Embrapa-Centro Nacional de Pesquisa de Soja, located at Londrina, PR, Brazil. Treatments consisted of insecticide application to control the velvetbean caterpillar (1/21/1993 or the stink bug complex (3/4/1993. Insect population was sampled through the shock technique, consisting of an application of a broad spectrum insecticide over the plants to be sampled, being the insects collected on cloths placed on the ground, and transferred to the laboratory to be identified and counted. Statistical analysis revealed no differences on the populations of species of predators, diptera or himenoptera as a group. No

  6. Interpersonal attraction and personality: what is attractive--self similarity, ideal similarity, complementarity or attachment security?

    Science.gov (United States)

    Klohnen, Eva C; Luo, Shanhong

    2003-10-01

    Little is known about whether personality characteristics influence initial attraction. Because adult attachment differences influence a broad range of relationship processes, the authors examined their role in 3 experimental attraction studies. The authors tested four major attraction hypotheses--self similarity, ideal-self similarity, complementarity, and attachment security--and examined both actual and perceptual factors. Replicated analyses across samples, designs, and manipulations showed that actual security and self similarity predicted attraction. With regard to perceptual factors, ideal similarity, self similarity, and security all were significant predictors. Whereas perceptual ideal and self similarity had incremental predictive power, perceptual security's effects were subsumed by perceptual ideal similarity. Perceptual self similarity fully mediated actual attachment similarity effects, whereas ideal similarity was only a partial mediator. PMID:14561124

  7. On the parasitoid complex of butterflies with descriptions of two new species of parasitic wasps (Hymenoptera: Eulophidae) from Goa, India.

    Science.gov (United States)

    Gupta, Ankita; Gawas, Sandesh M; Bhambure, Ravindra

    2015-11-01

    In comprehensive rearing of butterflies from Goa, India, an interesting parasitoid complex of wasps and tachinid flies was found. Two new species of parasitic wasps are described and illustrated: Tetrastichus thetisae n. sp. (Hymenoptera: Eulophidae), a gregarious parasitoid reared from the pupa of Curetis thetis (Drury) (Lepidoptera: Lycaenidae) on the host plant Derris sp., and Sympiesis thyrsisae n. sp. (Hymenoptera: Eulophidae), a gregarious parasitoid reared from the caterpillar of Gangara thyrsis (Fabricius) (Lepidoptera: Hesperiidae) on the host plant Cocos nucifera L. Additionally, the following host-parasitoid associations are recorded: Amblypodia anita Hewitson (Lepidoptera: Lycaenidae) with Parapanteles sp. (Hymenoptera: Braconidae); Coladenia indrani (Moore) (Lepidoptera: Hesperiidae) with Sympiesis sp. (Hymenoptera: Eulophidae); Danaus chrysippus L. (Lepidoptera: Nymphalidae) with Sturmia convergens (Wiedemann) (Diptera: Tachinidae); Idea malabarica Moore (Lepidoptera: Nymphalidae) with Brachymeria sp. (Hymenoptera: Chalcididae) and Palexorista sp. (Diptera: Tachinidae); Notocrypta curvifascia Felder & Felder (Lepidoptera: Hesperiidae) with Cotesia erionotae (Wilkinson) (Hymenoptera: Braconidae); and Rapala sp. (Lepidoptera: Lycaenidae) with an inominate species close to Aplomya spp. (Diptera: Tachinidae). This discovery is the first record of Tetrastichus as parasitoid of Curetis thetis, Sympiesis as parasitoid of Gangara thyrsis and Coladenia indrani, Brachymeria and Palexorista as parasitoids of Idea malabarica, and Cotesia erionotae as parasitoid of Notocrypta curvifascia. Data on habitat, brief diagnoses and host records for all parasitoids are provided. PMID:26446545

  8. Effect of Bacillus thuringiensis on Habrobracon hebetor during combined biological control of Plodia interpunctella

    Institute of Scientific and Technical Information of China (English)

    Akinkurolere Rotimi Oluwafemi; Qiong Rao; Xi-Qiao Wang; Hong-Yu Zhang

    2009-01-01

    The suitability of combining microbial pesticides and an insect parasitoid for pest management of stored cereal in China was evaluated using laboratory assays.For this purpose,interactions between Bacillus thuringiensis (Bt),Bt-intoxicated host larvae and the parasitoid Habrobracon hebetor (Say) (Hymenoptera:Braconidae) were alone caused 41.67% and 35.35% P.interpunctella larval mortality respectively.The Btparasitoid combined treatment significantly increased mortality of P.interpunctella (86%).Progeny development of H.hebetor was dependent upon its susceptibility to Bt.Fewer parasitoids emerged from Bt-parasitoid combined treatment than in non-Bt treatments.However,since Bt did not prevent parasitoid development,a combined treatment with Bt and parasitoid release could produce better protection against P.interpunctella than either treatments when used singly,because their lethal effects were additive to each other.

  9. Volatiles from whitefly-infested plants elicit a host-locating response in the parasitoid, Encarsia formosa.

    Science.gov (United States)

    Birkett, M A; Chamberlain, K; Guerrieri, E; Pickett, J A; Wadhams, L J; Yasuda, T

    2003-07-01

    The blend of volatile compounds emitted by bean plants (Phaseolus vulgaris) infested with greenhouse whitefly (Trialeurodes vaporariorum) has been studied comparatively with undamaged plants and whiteflies themselves. Collection of the volatiles and analysis by gas chromatography revealed more than 20 compounds produced by plants infested with whitefly. Of these, 4 compounds, (Z)-3-hexen-1-ol, 4,8-dimethyl-1,3,7-nonatriene, 3-octanone, and one unidentified compound were emitted at higher levels than from the undamaged control plants. Synthetic (Z)-3-hexen-1-ol, 4,8-dimethyl-1,3,7-nonatriene, or 3-octanone all elicited a significant increase in oriented flight and landing on the source by the parasitoid, Encarsia formosa, in wind tunnel bioassays. Two-component mixtures of the compounds and the three-component mixture all elicited a similar or, in most cases, a better response by the parasitoid, the most effective being a mixture of (Z)-3-hexen-1-ol and 3-octanone. These results demonstrate that E. formosa uses volatiles from the plant-host complex as olfactory cues for host location.

  10. Insulin signaling mediates sexual attractiveness in Drosophila.

    Directory of Open Access Journals (Sweden)

    Tsung-Han Kuo

    Full Text Available Sexually attractive characteristics are often thought to reflect an individual's condition or reproductive potential, but the underlying molecular mechanisms through which they do so are generally unknown. Insulin/insulin-like growth factor signaling (IIS is known to modulate aging, reproduction, and stress resistance in several species and to contribute to variability of these traits in natural populations. Here we show that IIS determines sexual attractiveness in Drosophila through transcriptional regulation of genes involved in the production of cuticular hydrocarbons (CHC, many of which function as pheromones. Using traditional gas chromatography/mass spectrometry (GC/MS together with newly introduced laser desorption/ionization orthogonal time-of-flight mass spectrometry (LDI-MS we establish that CHC profiles are significantly affected by genetic manipulations that target IIS. Manipulations that reduce IIS also reduce attractiveness, while females with increased IIS are significantly more attractive than wild-type animals. IIS effects on attractiveness are mediated by changes in CHC profiles. Insulin signaling influences CHC through pathways that are likely independent of dFOXO and that may involve the nutrient-sensing Target of Rapamycin (TOR pathway. These results suggest that the activity of conserved molecular regulators of longevity and reproductive output may manifest in different species as external characteristics that are perceived as honest indicators of fitness potential.

  11. Patterns and universals of mate poaching across 53 nations: the effects of sex, culture, and personality on romantically attracting another person's partner.

    Science.gov (United States)

    Schmitt, David P; Alcalay, Lidia; Allik, Jüri; Angleitner, Alois; Ault, Lara; Austers, Ivars; Bennett, Kevin L; Bianchi, Gabriel; Boholst, Fredrick; Borg Cunen, Mary Ann; Braeckman, Johan; Brainerd, Edwin G; Caral, Leo Gerard A; Caron, Gabrielle; Casullo, Maria Martina; Cunningham, Michael; Daibo, Ikuo; De Backer, Charlotte; De Souza, Eros; Diaz-Loving, Rolando; Diniz, Gláucia; Durkin, Kevin; Echegaray, Marcela; Eremsoy, Ekin; Euler, Harald A; Falzon, Ruth; Fisher, Maryanne L; Foley, Dolores; Fry, Douglas P; Fry, Sirpa; Ghayur, M Arif; Golden, Debra L; Grammer, Karl; Grimaldi, Liria; Halberstadt, Jamin; Haque, Shamsul; Herrera, Dora; Hertel, Janine; Hoffmann, Heather; Hooper, Danica; Hradilekova, Zuzana; Hudek-Kene-evi, Jasna; Jaafar, Jas; Jankauskaite, Margarita; Kabangu-Stahel, Heidel; Kardum, Igor; Khoury, Brigitte; Kwon, Hayrran; Laidra, Kaia; Laireiter, Anton-Rupert; Lakerveld, Dustin; Lampert, Ada; Lauri, Maryanne; Lavallée, Marguerite; Lee, Suk-Jae; Leung, Luk Chung; Locke, Kenneth D; Locke, Vance; Luksik, Ivan; Magaisa, Ishmael; Marcinkeviciene, Dalia; Mata, André; Mata, Rui; McCarthy, Barry; Mills, Michael E; Mkhize, Nhlanhla J; Moreira, João; Moreira, Sérgio; Moya, Miguel; Munyae, M; Noller, Patricia; Opre, Adrian; Panayiotou, Alexia; Petrovic, Nebojsa; Poels, Karolien; Popper, Miroslav; Poulimenou, Maria; P'yatokha, Volodymr; Raymond, Michel; Reips, Ulf-Dietrich; Reneau, Susan E; Rivera-Aragon, Sofia; Rowatt, Wade C; Ruch, Willibald; Rus, Velko S; Safir, Marilyn P; Salas, Sonia; Sambataro, Fabio; Sandnabba, Kenneth N; Schulmeyer, Marion K; Schütz, Astrid; Scrimali, Tullio; Shackelford, Todd K; Shaver, Phillip R; Sichona, Francis; Simonetti, Franco; Sineshaw, Tilahun; Sookdew, R; Speelman, Tom; Spyrou, Spyros; Sümer, H Canan; Sümer, Nebi; Supekova, Marianna; Szlendak, Tomasz; Timmermans, Bert; Tooke, William; Tsaousis, Ioannis; Tungaraza, F S K; van Overwalle, Frank; Vandermassen, Griet; Vanhoomissen, Tim; Vanwesenbeeck, Ine; Vasey, Paul L; Verissimo, João; Voracek, Martin; Wan, Wendy W N; Wang, Ta-Wei; Weiss, Peter; Wijaya, Andik; Woertman, Liesbeth; Youn, Gahyun; Zupanèiè, Agata

    2004-04-01

    As part of the International Sexuality Description Project, 16,954 participants from 53 nations were administered an anonymous survey about experiences with romantic attraction. Mate poaching--romantically attracting someone who is already in a relationship--was most common in Southern Europe, South America, Western Europe, and Eastern Europe and was relatively infrequent in Africa, South/Southeast Asia, and East Asia. Evolutionary and social-role hypotheses received empirical support. Men were more likely than women to report having made and succumbed to short-term poaching across all regions, but differences between men and women were often smaller in more gender-egalitarian regions. People who try to steal another's mate possess similar personality traits across all regions, as do those who frequently receive and succumb to the poaching attempts by others. The authors conclude that human mate-poaching experiences are universally linked to sex, culture, and the robust influence of personal dispositions. PMID:15053706

  12. Global Attraction to Solitary Waves

    OpenAIRE

    Komech, Andrey

    2009-01-01

    The long time asymptotics for nonlinear wave equations have been the subject of intensive research, starting with the pioneering papers by Segal, Strauss, and Morawetz, where the nonlinear scattering and local attraction to zero were considered. Global attraction (for large initial data) to zero may not hold if there are quasistationary solitary wave solutions. We will call such solutions "solitary waves". Other appropriate names are "nonlinear eigenfunctions" and "quantum stationary states"....

  13. Is beauty in the eye of the beholder? Effects of weight and shape on attractiveness ratings of female line drawings by restrained and nonrestrained eaters.

    Science.gov (United States)

    Forestell, Catherine A; Humphrey, Tara M; Stewart, Sherry H

    2004-05-01

    This study tested the differences between restrained and nonrestrained eaters' attractiveness perceptions of female line drawings, of their own figures, and the ideal female figure. Female line drawings varied systematically in body weight and in waist and hip circumference. Forty-six female undergraduate students, 23 nonrestrainers and 23 restrainers, rated stimuli in attractiveness, identified the figure which best represented their own body type (PAF), and the ideal body figure (IF) according to the Restraint Scale [RS; Herman, C. P., & Polivy, J. (1980). Restrained eating. In: A. Stunkard (Ed.), Obesity (pp. 208-225). Philadelphia, PA: Saunders]. Restrainers did not generally differ from nonrestrainers in attractiveness ratings or in their choice of IF. However, differences between IF and PAF were larger in restrainers than in nonrestrainers because restrainers chose PAFs with larger hips than nonrestrainers did. This difference between the restraint groups was independent of between-group differences in hip size. This discrepancy between IF and PAF may contribute to the restrainers' motivation to diet. PMID:15093780

  14. Coexistence and niche segregation by field populations of the parasitoids Cotestia glomerata and C. rubecula in the Netherlands: predicting field performance from laboratory data

    NARCIS (Netherlands)

    Geervliet, J.B.F.; Verdel, M.S.W.; Snellen, H.; Schaub, J.; Dicke, M.; Vet, L.E.M.

    2000-01-01

    Field experiments with foraging parasitoids are essential to validate the conclusions from laboratory studies and to interpret differences in searching and host selection behaviour of parasitoid species. Furthermore, field experiments can indicate whether the parameters measured in the laboratory ar

  15. Coexistence and niche segregation by field populations of the parasitoid Cotesia glomerata and C. rubecula in the Netherlands : predicting field performance from laboratory data

    NARCIS (Netherlands)

    Geervliet, J.B.F.; Verdel, M.S.W.; Snellen, H.; Schaub, J.; Dicke, M.; Vet, L.E.M.

    2000-01-01

    Field experiments with foraging parasitoids are essential to validate the conclusions from laboratory studies and to interpret differences in searching and host selection behaviour of parasitoid species. Furthermore, field experiments can indicate whether the parameters measured in the laboratory ar

  16. Econometric Analysis of the Market Share Attraction Model

    OpenAIRE

    Fok, Dennis; Franses, Philip Hans; Paap, Richard

    2001-01-01

    textabstractMarket share attraction models are useful tools for analyzing competitive structures. The models can be used to infer cross-effects of marketing-mix variables, but also the own effects can be adequately estimated while conditioning on competitive reactions. Important features of attraction models are that they incorporate that market shares sum to unity and that the market shares of individual brands are in between 0 and 1. Next to analyzing competitive structures, attraction mode...

  17. Trap effects of different physical and chemical attractants on Culex pipiens quinquefasciatus%不同物理、化学因子对致倦库蚊的引诱效果研究

    Institute of Scientific and Technical Information of China (English)

    谷依露; 高小峰; 杨晓菁; 葛台明

    2012-01-01

    Objective To observe the trap effects of several different physical and chemical attractants on adult Culex pipiens quinquefasciatus, providing better designs of new mosquito trap devices. Methods The "Y" - tube olfactometer was used to measure the trap effects of seven chemicals (urea, lactic acid, glycerol, dodecanoic acid, tetradecanoic acid, hexadecanoic acid and nonyl aldehyde) and two physical attractants (sound and visible light) on adult Cx. Pipiens quinquefasciatus. The number of individuals attracted by the tested attractants was calculated and compared among the groups. Results Chemical attractants including urea (10 mg/L), lactic acid (1000 mg/L), hexadecanoic acid (10 mg/L), nonyl aldehyde (0.1 mg/L) and physical attractants including 150 Hz sinus tone and 380 nm visible light had better mosquito trap effects. Conclusion The chemical and physical attractants mentioned above can be introduced to the design of mosquito trap devices to improve the efficiency of mosquito control.%目的 研究不同物理、化学因子对致倦库蚊的引诱效果,以更好地设计改进新一代灭蚊器.方法 使用Y形嗅觉测试仪测定化学因子(尿素、乳酸、丙三醇、十二烷酸、十四烷酸、十六烷酸、壬醛)以及物理因子(声波和可见光)对致倦库蚊成虫的引诱作用;将致倦库蚊成虫逐只放入Y形嗅觉测试仪,统计飞入处理端的个体数,通过比较得出对致倦库蚊具有较好引诱效果的物理、化学因子.结果 对致倦库蚊具有较高引诱率的化学因子有尿素(10 mg/L)、乳酸(1000 mg/L)、十六烷酸(10 mg/L)和壬醛(0.1 mg/L);物理因子中150 Hz的正弦波和380 nm的可见光分别对致倦库蚊具有较高引诱率.结论 可将上述引诱效果较佳的物理、化学因子引入到灭蚊器的设计生产中,以提高灭蚊效率.

  18. Effects of effective attractive multi-body interaction on quantum phase and transport dynamics of a strongly correlated bosonic gas across the superfluid to Mott insulator transition

    International Nuclear Information System (INIS)

    We theoretically investigate quantum phases and transport dynamics of ultracold atoms trapped in an optical lattice in the presence of effective multi-body interaction. When a harmonic external potential is added, several interesting phenomena are revealed, such as the broadening and the emergence of a central insulator plateau and the phase transition between superfluid and Mott insulator phase. We also study the transport of the system which runs across the superfluid—insulator transition after ramping up the lattice, and predict a slower relaxation which is attributed to the influence of the multi-body interaction on the mass transport

  19. Neochrysocharis okazakii (Hymenoptera: Eulophidae) as a Major Parasitoid Wasp of Stone Leek Leaf Miner Liriomyza chinensis (Diptera: Agromyzidae) in Central Vietnam

    OpenAIRE

    Takatoshi Ueno; Dang Hoa Tran

    2015-01-01

    Liriomyza chinensis is a major pest of Welsh onion Allium fistulosum in Asia but little is known about the abundance of its natural enemies. A field survey was made to explore the major parasitoids of L. chinensis leaf miner in central Vietnam. An eulophid parasitoid, Neochrysocharis okazakii, comprised more than 95% of parasitoids reared from leaf miner larvae collected in the onion field and 98.3% of leaf miner parasitoids found during searches of onion plants. The mean number of female N. ...

  20. Improved attractants for enhancing tsetse fly suppression

    International Nuclear Information System (INIS)

    At the initiation of this co-ordinated research project (CRP), the available visually attractant devices and odours for entomological monitoring and for suppression of tsetse fly populations were not equally effective against all economically important tsetse fly species. For species like G. austeni, G. brevipalpis, G. swynnertoni and some species of the PALPALIS-group of tsetse flies no sufficiently effective combinations of visual or odour attractants were available for efficient suppression and standardized monitoring as part of an operational integrated intervention campaign against the tsetse and trypanosomosis (T and T) problem. The Co-ordinated Research Project on Improved Attractants for Enhancing the Efficiency of Tsetse Fly Suppression Operations and Barrier Systems used in Tsetse Control/Eradication Campaigns involved (a) the identification, synthesis and provision of candidate kairomones, their analogues and of dispensers; (b) laboratory screening of synthesised candidate kairomones through electrophysiological studies and wind tunnel experiments; (c) field tests of candidate kairomones alone or as part of odour blends, in combination with available and or new trap designs; and (d) analysis of hydrocarbons that influence tsetse sexual behaviour. The CRP accomplished several main objectives, namely: - The screening of new structurally related compounds, including specific stereoisomers, of known tsetse attractants resulted in the identification of several new candidate odour attractants with promising potential. - An efficient two-step synthetic method was developed for the pilot plant scale production of 3-n-propyphenol, synergistic tsetse kairomone component. - Electrophysiological experiments complemented with wind tunnel studies provided an efficient basis for the laboratory screening of candidate attractants prior to the initiation of laborious field tests. - New traps were identified and modifications of existing traps were tested for some species