The Population Dynamic Consequences of Phenological Asynchrony between Parasitoids and their Hosts

Abstract

1. Populations of hosts and parasitoids with discrete generations frequently show imperfect phenological synchronization resulting in some hosts experiencing reduced or even no risk of parasitism. 2. The population dynamic consequences of phenological asynchrony are explored by modelling within-generation dynamics by a set of delay-differential equations. 3. Phenological asynchrony can stabilize an otherwise unstable interaction. The influence of the interaction between phenological asynchrony and other stabilizing forces on the stability and equilibrium population densities of hosts and parasitoids is studied. 3. Preliminary results indicate that annual fluctuations in the synchrony between host and parasitoid populations can have a major effect on the persistence of the interaction.