BOKU - Universität für Bodenkultur Wien - Forschungsinformationssystem

Logo BOKU-Forschungsportal

¿Evaluating the Use of Nuclear Techniques for the Colonization and Production of Natural Enemies of Agricultural Insect Pests¿

Projektleitung
Schopf Axel, Projektleiter/in
Laufzeit:
01.10.1999-31.12.2003
Art der Forschung
Angewandte Forschung
Projektpartner*innen
IAEA-Laboratory Seibersdorf, Österreich.
Funktion des Projektpartners: Koordinator
Mitarbeiter*innen
Hoch Gernot, Projektmitarbeiter/in
Beteiligte BOKU-Organisationseinheiten
Institut für Forstentomologie, Forstpathologie und Forstschutz
Gefördert durch
Abstract
In order to study the effects of parasitoid associated factors on lepidopteran larval hosts we used g-irradiation of sterilize females of the braconid parasitoid Glyptapanteles liparidis. Along with eggs, G. liparidis females inject a secrete of the calyx gland containing particles of a symbiotic virus, the polydnavirus (PDV) and venom into the host. These associated factors are known from other host-parasitoid systems to suppress the immune system of the host and cause alterations in its development. g-irradiation should sterilize the eggs inside the wasp's ovary, so that sterile eggs are oviposited together with PDV and venom and the influence of parasitoid larvae inside the host is excluded.
We irradiated G. liparidis females with different doses, ranging from 2.4 to 10.5 krad, in a Co60 g-irradiator. L. dispar larvae were stung by such irradiated wasps as well as untreated wasps, and the development of hosts and parasitoid progeny was controlled by rearing and dissections of hosts. Also G. liparidis were reared under controlled conditions to measure the effect of irradiation on their longevity and oviposition.
A sting by an irradiated wasp (= pseudoparasitization) caused prolonged development and supernumerary molts of L. dispar larvae, and lead to the production of heavier pupae. However, such pseudoparasitized hosts suffered from higher pupal mortality ¿ due to incomplete larval-pupal molts or incomplete hardening of pupal cuticle. Effects on the host immune system were studied indirectly using an additional infection with the entomopathogenic microsporidium Vairimorpha sp. Pseudoparasitized hosts died earlier from the microsporidiosis and showed infections of higher intensity. For G. liparidis adults the g-irradiation caused no marked reduction in lifespan, except at the highest dose of 10.5 krad, but irradiated females laid significantly fewer eggs. The treatment did not result in complete sterilisation; about 10 to 20 % of parasitoid eggs did hatch and such G. liparidis were able to complete their development to adults. Further studies will investigate the incomplete sterilization of G. liparidis eggs by g-irradiation. We will test whether these synovigenic wasps can recover after a certain time after irradiation and produce fertile eggs again. Consequently, we aim to develop a protocol of dose and timing of g-irradiation to give the best results for using it as a tool in studying the effects of PDV and venom of G. liparidis.
Schlagworte
Biophysik; Tierphysiologie; Forstentomologie;
Glyptapanteles liparidis; Kobaltstrahlung; Lymantria dispar; PolyDNA-Virus; Wirt-Parasit-Beziehung;
Publikationen

** Tillinger N.A., Hoch G., Schopf A. Effects of parasitoid associated factors of the endoparasitoid Glyptapanteles liparidis (Hymenoptera: Braconidae)..

Eur.J.Entomol., 101, 243-249 WoS FullText FullText_BOKU

Vorträge
© BOKU Wien Impressum