9801537 Moran and Stireman This research is concerned with the factors that determine the host range of parasitic insects. Many parasites are highly specialized and generally incapable of moving between hosts. In contrast, tachinid flies that act as parasites (Diptera; Tachinidae) tend to exhibit wide host ranges. There is relatively little understanding of what ecological factors determine the range of hosts utilized by a parasitoid. The PIs hypothesize that tachinid host ranges are primarily determined by the search strategies used to find host species. Their research will take three approaches: 1) it will involve a comparison of host-related behaviors of two species that vary in host specificity, 2) examine the patterns of host use by a community of tachinid parasitoids in the field and 3) analyze the evolutionary patterns of host use in a subgroup of the family. By integrating information from these three levels of inquiry, they will further our understanding of the development and ecological modification of parasitoid-host associations.
