38th Annual Meeting of the Society for Invertebrate Pathology

Mathematical models have long been used to generate qualitative insights about disease spread. Increasingly, however, models are also used as statistical tools for understanding data, and thus as testable, quantitative hypotheses. Work in my lab uses models to understand pathogens of the gypsy moth, Lymantria dispar. By adding stochasticity to an existing disease model, we have developed a method of using infection rate data to make inferences about mechanisms of disease spread. This work has suggested that heterogeneity in susceptibility among gypsy moth larvae plays an important role in NPV transmission. We are extending this approach to disentangle the effects of the NPV and the fungal pathogen Entomophaga maimaga on gypsy moth population dynamics. In addition, we are developing methods of using models to make inferences about NPV sequence data. This latter work has suggested first that geographic separation plays only a small role in the evolution of this virus. Also, our data have shown that, at the 25K fp locus, which affects polyhedron size and number, there is a high-frequency polymorphism. By allowing for pathogen variability in our models, we are attempting to understand the consequences of this polymorphism for the spread of the NPV.