Effect of biotic and abiotic factors on reproductive parameters of the synovigenic endoparasitoid Venturia canescens |
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Authors: | Panagiotis A Eliopoulos§ Jeff A Harvey Christos G Athanassiou§ George J Stathas† |
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Institution: | Agricultural University of Athens, Laboratory of Agricultural Zoology and Entomology, Athens, Greece,;Centre for Terrestrial Ecology, Netherlands Institute of Ecology, Heteren, the Netherlands and;Technological Educational Institute of Kalamata, Department of Crop Production, Kalamata, Greece |
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Abstract: | Abstract. The main effects and interactions of adult age, access to food and host deprivation, on the egg load of Venturia canescens (Gravenhorst) (Hymenoptera: Ichneumonidae), a larval parasitoid of Ephestia kuehniella (Lepidoptera: Pyralidae) and other pyralids, were studied in the laboratory. Intraspecific variation in the number of ovarioles was also studied. There was a positive and significant correlation between wasp size and both egg load and ovariole number, with the reproductive system of large wasps containing significantly more ovarioles and mature eggs than small wasps. Newly emerged adult wasps contained 27 ± 2.4 ovulated (mature) eggs in their lateral oviducts. Access to food and host deprivation were the only conditions under which egg load increased with parasitoid age. Wasps that had access to hosts immediately after emergence showed a significant decline in their egg complement, irrespective of food presence. Under conditions of both host and food deprivation, there was practically no alteration of egg load with parasitoid age. A three-way analysis of variance revealed that egg load varies significantly with food or host access but not with parasitoid age. All interactions among the three factors were significant. It is confirmed that there is no egg resorption in V. canescens and that egg production stops in the absence of food. |
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Keywords: | Ephestia kuehniella egg load egg resorption female reproductive system host deprivation pyralidae synovigeny Venturia canescens |
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