A 3 VARIABLE DIFFERENTIAL-EQUATION MODEL FOR GYPSY-MOTH POPULATION-DYNAMICS

The dynamics of gypsy moth, Lymantria dispar (Lepidoptera: Lymantriida e), populations are extremely complex. As a result, many of the models which have been proposed to model these populations are likewise very complicated. This complexity makes analysis of the underlying dynamic s difficult. In this work a model is proposed which involves only thre e variables: gypsy moth biomass density, foliage biomass density and n atural enemy biomass density. The dynamics of this model are shown to include period doubling as a route to chaos, among other interesting n onlinear phenomena. The model also evidences similar behavior to that noted from field studies in which researchers attempted to artificiall y stimulate outbreaks of gypsy moths. While these attempts failed in n ature and in the model, the model predicts that under certain circumst ances it may be possible to stimulate these outbreaks.