This project of both field and laboratory research intends to determine whether damage-induced changes in oak leaf traits have a net negative or positive influence on the gypsy moth (GM). Previous work demonstated that damage-induced increases in leaf phenolics can depress larval growth and adult fecundity by 30% or more (Rossiter et al. 1988). Thus tree responses could have a negative impact on GM populations. Phenolic levels even lower than those exhibited by induced tree leaves strongly inhibit infection of GM larvae by the Gypsy Moth Nuclear Polyhedrosis Virus (GMNPV). Hence, the possibility exists that induced "defenses" in oaks actually benefit the GM. These studies are designed to compare these two effects and provide information allowing us to infer the net influence of induction - positive or negative - on the GM. The project team will use GM larvae to generate damage-induced changes in leaf traits, rear larvae on induced and control leaves, and assess the influence of these diets on GMNPV effectiveness. The results will permit a comparison of induction's ability to reduce fecundity with its impact on mortality in GM populations, and will clarify the relationship between hostplant chemistry and the success of this forest pest. Results will contribute to ecological theory on pathogen/plant/animal interactions and will be of immediate interest to forest managers.//
