The Dynamics of Optimally Foraging Predators and Parasitoids

Abstract

(1) Our aim in this paper is to bridge the gap between optimal foraging models and predator-prey or parasitoid-host population models. (2) The parasitoid optimal foraging model that we derive assumes each individual parasitoid to maximize its rate of encounter with healthy hosts in a patchy environment. (3) The model is used to generate the searching strategy of a population of parasitoids, from which their overall searching efficiency can be calculated. (4) We then explore the dynamics of a difference equation population model in which the parasitoids forage optimally. The conditions for local stability are derived and some global properties discussed. (5) We conclude that although optimal foraging is important to parasitoid reproductive fitness, the resulting dynamics are qualitatively similar to those produced by the model of Hassell & May (1973) in which the parasitoids do not forage optimally but have a fixed aggregation strategy.