Biology, behavior, and genetic diversity of Trichogramma aurosum Sugonjaev & Sorokina

Abstract

Trichogramma aurosum Sugonjaev & Sorokina has been collected from several hosts, including eggs of Nematus spp. (Hymenoptera: Tenthredinidae), noctuids and also from a major insect pest of fruit orchards, Cydia pomonella (L.). However, nothing is known about the biology and behavior of this species. Since T. aurosum might be a potential candidate for attempts at controlling C. pomonella, research work has been started to assess its biology and behavior towards eggs of this pest. As a first step, T. aurosum was collected in several locations in Germany. Studies on genetic diversity as well a molecular comparison with morphologically close related species have been started. Secondly, an appropriate factitious host has been found to reproduce T. aurosum in quantities enough for mass release. Contrary to most Trichogramma species, females of T. aurosum do not accept eggs of Sitotroga cerealella for parasitization, while this is not the case with eggs of Ephestia kuehniella. Populations of different geographic origin will be tested towards their parasitization capacity, fecundity, longevity, host age and host preference in order to obtain suitable strains for potential use in biological control. Furthermore, their adaptation to adverse biotic conditions will be assessed in form of life-table studies. As T. aurosum is of holarctic nature, the degree of conspecifity with North American populations might provide useful information for phylogenetic studies. For this, cooperation work with the University of California-Riverside is focussed.