Cotesia congregata polydnavirus (CcPDV) is essential for successful parasitism of Manduca sexta larvae by the braconid wasp Cotesia congregata. To determine the molecular mechanisms for the vertical transmission of CcPDV in the wasps, we analysed the different forms of the virus sequences containing the gene encoding the early parasitism-specific protein 1 (EP1). By a detailed molecular analysis, we demonstrated that the EP1 sequences are present in wasp DNA in two forms : a circular form as seen in the virus particles and a form integrated into the wasp genome. Moreover, we showed that the integrated form of the EP1 sequences is able to excise in the ovary cells. A fragment corresponding

The ovaries of endoparasitic species of braconid and ichneumonid wasps contain large numbers of polydnavirus (PDV) virions that replicate in specialized calyx cells of the ovaries and are injected into the host larva during parasitization. In the braconid wasp Cotesia congregata that parasitizes the tobacco hornworm, Manduca sexta, the total amount of viral DNA present in the ovaries was determined to be 25-75 ng. Analysis of viral DNA on 0.4% agarose gels showed that the genome was comprised of 15-20 circles of double-stranded DNA. SDS-PAGE analyses showed that a large number (>30) of structural polypeptides were present in the virions, and analysis of the venom likewise showed that multiple components were present. The major size classes of venom proteins differed from those present in the PDV. However, Western blots using polyclonal PDV antibodies showed that some cross-reacting PDV-like proteins were present in the venom, perhaps explaining the mild PDV-enhancing effect of the venom. Injection of PDV into unparasitized larvae provoked pronounced alterations in their growth, development, pigmentation, and hemolymph proteins. A densely staining band of hemolymph proteins of approximately 18-20 kD appeared in large amounts relative to other hemolymph proteins several days following injection of PDV; this band was undetectable in naturally parasitized larvae. Eggs which had been washed extensively to remove PDVs were encapsulated following injection, but development of the host still was disrupted, usually in the post-wandering prepupal stage. Thus,

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Ecdysone agonists are hormonally active insect growth regulators that disrupt development of pest insects and have potential for development as insecticides. Their effects have been particularly well-studied in Lepidoptera and Coleoptera, but significantly less is known about their effects on dipterans, particularly aquatic species. The potency of three ecdysone agonists on larvae of 3 mosquito species, Aedes aegypti, Anopheles gambiae, and Culex quinquefasciatus, was examined. Anopheles gambiae was the most susceptible species and Ae. aegypti was the most resistant species to the effects of the three compounds tested. Potency, in descending order, was RH-2485 > RH-5992 > RH-5849. Dose-response relationships were determined for the three agonists; RH-2485 was found to be the most effective endocrine disruptor against all three species. The observed biological effects of these compounds were similar to those reported for other insects, and mosquitoes initiated molting and apolysis but did not complete a molt. In some cases, mosquito larvae synthesized a new cuticle that appeared to be normally sclerotized but the larvae failed to ecdyse and shed the exuvium. These compounds may prove to be valuable insect growth regulators for control of mosquitoes to decrease the frequency of pathogen transmission to humans. Prospects for using these compounds to control mosquitoes in the field are discussed, along with possible impacts on non-target arthropods in mosquito habitats.

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