Parasitoid searching efficiency links behaviour to population processes

Abstract

Parasitoid searching efficiency is central to parasitoid-host population dynamics, to the evolution of parasitoid and host behaviour, and to the application of parasitoids as natural enemies of insect pests in biological control. Students of parasitoid behaviour attempt to explain variability in parasitoid searching behaviour, while population dynamicists are more concerned with variation in the outcome of parasitism and how this affects the spatial distribution of host mortality and population stability. Unfortunately the links between behaviour and population processes have been rarely explicitly made. Parasitoid searching efficiency potentially links behaviour to population processes since it affects the temporal and spatial heterogeneity of host attacks. But which behaviours determine searching efficiency? In the present paper I attempt to identify some of these key behaviours. They involve responses to cues that help parasitoids to assess important characteristics of the spatial distribution of their hosts such as which food plants hosts are feeding on, the host distribution pattern on food plants and the host density and patch quality. Plant information plays an essential role in many of these processes. In the present paper I will discuss both the behavioural mechanisms involved and the potential effect for population processes.