Search results for "Hymen"
showing 10 items of 287 documents
Larval distributions of the ectoparasitoid waspEurytoma robustarelative to the host tephritid gall flyUrophora cardui
2003
Parasitism may explain the patchy distributions of host populations. The present paper is a study of larval distributions of the parasitoid Eurytoma robusta in galls of the tephritid gall fly Urophora cardui . It focuses on E. robusta ’s choice of U. cardui gall and whether this changes relative to the rate of parasitism. Oviposition patterns were inferred by direct counts of larvae in galls and genetically, for both species, using indirect relatedness estimates between gall-members. Furthermore, rates of parasitism in four populations were monitored for 4 years. The modal distribution of E. robusta larvae per gall was one and independent of the level of parasitism. The mean number of E. ro…
Effect of the juvenile hormone analogue fenoxycarb applied via the host on the parasitoid Phanerotoma (Phanerortoma) ocularis Kohl (Hym. Braconidae)
1993
Abstract Concentrations of 0.001, 0.005, 0.01, 0.05 and 0.1 μg/ml of fenoxycarb (Ro 13-5223) were applied topically to larvae of Ephestia kuehniella Zeller parasitized by Phanerotoma (Phanerotoma) ocularis Kohl. The effect of the treatment and concentration on parasitism rates, preimaginal mortality and emergence rates of the parasitoid were studied comparatively for each larval instar of the host considered. The preimaginal mortality was high when the fenoxycarb was applied on the first larval instar of the host (23–46%) and more higher when applied to the sixth larval instar of the host (40–86%). Consequently, fenoxycarb treatment of the last larval instar of the host produced a reduction…
Hymenopteran specificity of Bacillus thuringiensis strain PS86Q3
2008
Abstract The biological activity of Bacillus thuringiensis (Bt) strain PS86Q3 against five Hymenopteran species was determined by means of bioassays adapted to each species. Four species of sawfly that are important pests of conifers (Diprion pini, Gilpinia hercyniae and Pristiphora abietina) or ornamental plants (Arge rosae), as well as the non-target honeybee, Apis mellifera, were studied. Two out of the four sawfly species tested were found to be sensitive to PS86Q3 crystals or spore/crystal suspensions. A sporulated culture of this strain was moderately active on D. pini, and a complete bioassay with solubilized crystals was performed to estimate the LC50 of 4.9 mg/ml. Pristiphora abiet…
Parasitization ofEphestia kuehniellaZeller (Lep., Pyralidae) byPhanerotoma (Phanerotoma) ocularisKohl (Hym., Braconidae)
1993
Laboratory studies of the parasitism by P. (P.) ocularis into E. kuehniella showed that this parasitoid had a great capacity to parasitize the host. Real parasitism rate turned between 84.5% and 100% whereas effective parasitism and adult emergence rate were, comparatively, lower. Superparasitism rate was low (16.57 %). Zusammenfassung Parasitierung von Ephestia kuehniella Zeller (Lep., Pyralidae) durch Phanerotoma (Phanerotoma) ocularis Kohl (Hym., Braconidae). Parasitismus, Superparasitismus und Schlupfraten Laboruntersuchungen zur Parasitierung von Ephestia kuehniella durch P. (P.) ocularis zeigten, das dieser Parasitoid eine sehr hohe Parasitierungsleistung hat. Die reale Rate lag zwisc…
Exposing the structure of an Arctic food web
2015
15 pages; International audience; How food webs are structured has major implications for their stability and dynamics. While poorly studied to date, arctic food webs are commonly assumed to be simple in structure, with few links per species. If this is the case, then different parts of the web may be weakly connected to each other, with populations and species united by only a low number of links. We provide the first highly resolved description of trophic link structure for a large part of a high-arctic food web. For this purpose, we apply a combination of recent techniques to describing the links between three predator guilds (insectivorous birds, spiders, and lepidopteran parasitoids) a…
Revision of Afrotropical Dyscritobaeus Perkins, 1910 (Hymenoptera: Scelionidae)
2016
A revision of Afrotropical species of Dyscritobaeus Perkins is presented with re-description of the four known species ( D. bicolor O’Connor et Ashe, D. comitans Perkins, D. parvipennis (Dodd) and D. sulawensis Mineo, O’Connor et Ashe) and description of six new species ( D. antananarivensis Tortorici et Caleca sp. nov., D. flavus Tortorici et Caleca sp. nov. , D. kilimanjarensis Tortorici et Caleca sp. nov. , D. madagascarensis Tortorici et Caleca sp. nov. , D. ndokii Tortorici et Caleca sp. nov. and D. tanzaniensis Tortorici et Caleca sp. nov.). Dyscritobaeus cerosus is considered to be a junior synonym of D. comitans , D. hannibal is considered to be a junior synonym of D. sulawensis and…
Effect of host kairomones and oviposition experience on the arrestment behavior of an egg parasitoid
2006
SUMMARY Chemical residues left by walking adults of the southern green stink bug, Nezara viridula (L.) (Heteroptera: Pentatomidae) induce arrestment behavior in the egg parasitoid Trissolcus basalis (Wollaston)(Hymenoptera: Scelionidae) leading to prolonged periods of walking on contaminated areas and to systematic return to the stimulus after encountering the treatment borders. In this study, we quantified how the hierarchical value of residues from host adults and oviposition experience can influence the arrestment behavior of T. basalis females. Our results showed that:(1) female wasps perceived host residues at different hierarchical levels depending on the host gender, with a clear pre…
Honeybees produce millimolar concentrations of non-neuronal acetylcholine for breeding: possible adverse effects of neonicotinoids
2016
The worldwide use of neonicotinoid pesticides has caused concern on account of their involvement in the decline of bee populations, which are key pollinators in most ecosystems. Here we describe a role of non-neuronal acetylcholine (ACh) for breeding of Apis mellifera carnica and a so far unknown effect of neonicotinoids on non-target insects. Royal jelly or larval food are produced by the hypopharyngeal gland of nursing bees and contain unusually high ACh concentrations (4–8 mM). ACh is extremely well conserved in royal jelly or brood food because of the acidic pH of 4.0. This condition protects ACh from degradation thus ensuring delivery of intact ACh to larvae. Raising the pH to ≥5.5 and…
A finely tuned strategy adopted by an egg parasitoid to exploit chemical traces from host adults.
2009
SUMMARY Scelionid egg parasitoids can obtain reliable information on the presence of host eggs by discriminating host gender on the basis of chemical footprints of their co-evolved hosts, with a strong preference for the footprint left by host females. Based on the concept of dietary specialization and infochemical use in natural enemies, it could be predicted that host gender discrimination in specialist species belonging to the genus Trissolcus is further tuned to specific cues from distinctive chemical traces left by host females as a consequence of copulation and/or oviposition. To test this hypothesis we used the system Murgantia histrionica – Trissolcus brochymenae. Our results showed…
Quantitative parameters and ecological implications of a specialized tritrophic interaction involving a seed-feeding tortricid, Pseudargyrotoza conwa…
2014
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