Maternal effects on gypsy moth (Lepidoptera : Lymantriidae) population dynamics: A field experiment

Previous studies have postulated that the quality of resources that female gypsy moths, Lymantria dispar (L.), allocate to their eggs may affect the g rowth, development, and population dynamics of larvae in subsequent generat ions. To test this hypothesis, we collected eggs from food stressed and uns tressed populations and measured critical life history parameters (e.g., di spersal, growth rate, mortality, fecundity) of gypsy moth larvae with a com bination of field and laboratory experiments. Larvae from stressed and unst ressed source populations showed no differences in overall dispersal, morta lity from pathogens and parasitoids, or developmental rate. In smaller labo ratory and field rearing studies, there were no significant differences in the relative growth rates, female pupal weights, or fecundity between larva e from stressed and unstressed populations. However, we found that the prop ortion of males in egg masses from stressed populations were 11% higher tha n those from unstressed populations. In addition, there was a significant r elationship between egg mass size and proportion of males in one of 2 yr of the study. We conclude that nutritionally mediated maternal effects have a relatively minor influence on the population dynamics of the gypsy moth.