One of the major objectives of the field of ecology is understanding the mechanisms by which biotic and abiotic forces determine the abundance and distribution of organisms. Although previous studies have examined various genetic and enviromental factors that predispose individual host organisms to infection by parasites, few attempts have been made to understand how population level characteristics of the host affect their susceptibility to parasites in natural habitats. The proposed research will experimentally examine the ways in which characteristics of terrestrial isopod populations affect their susceptibility to a lethal virus. Experiments in natural habitats will examine the interaction of isopod density and nutritional state with physical characteristics of the habitat which in turn affect their patterns of aggregation and movement. Current theoretical models of host and parasite population dynamics suggest that fragmentation of a host population into smaller groups may be very important in determining the rates of transmission of viruses through the host population. Viruses have become important biological control agents in recent years and their full potential has yet to be realized. Understanding the factors that determine the effectiveness of a given control agent is important to ensure the success of that agent, and this study may increase our understanding of how and when applications of control agents will be most effective. Also, since isopods are very general in their feeding habitats and can disperse over significant distances, they are likely to be one of the most important soil organisms in terms of their ability to disperse genetically engineered microbes. As the use of genetically engineered organisms increases, more attention must be paid to the degree to which these microbes are dispersed by isopods and other soil biota.
