Research Starter Grant. The Consequences of Variation in Predator-Prey Interactions: Models and Tests Using a Seed-Beetle and Parasitoid

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Research Starter: The Consequences of Variation in Predator-Prey Interactions: Models and Tests Using a Seed-Beetle and Parasitoid.Inouye, Brian D. Florida State University DEB: 0309177Parasitoids are common and diverse members of most ecosystems that play an important role in limiting insect herbivore populations. Due in part to their ecological and economic significance, host-parasitoid interactions have been the subject of many previous empirical and theoretical studies. To compliment on-going fieldwork and modeling efforts, this project will use populations of the seed-feeding bruchid weevil Callosobruchus maculatus and the parasitoid Anisopteromalis calandrae as a model system for studying factors affecting population regulation and stability. One of the major mechanisms thought to stabilize host and parasitoid population dynamics is heterogeneity in parasitoid attack rates. Such heterogeneity may occur when a parasitoid must search for its host in a patchy environment, for example when the host is a polyphagous herbivorous insect that feeds differentially on a number of types of resource plants. One goal of this research project will be to parameterize a model of host-parasitoid interactions including these alternative resources of the host, in order to test hypotheses about host and parasitoid population stability. First the functional responses of parasitoids attacking C. maculatus in several species or varieties of legume seeds will be characterized, in order to identify alternative resources that provoke different patterns of parasitoid attack. In a second stage of experiments, the effects of the resource driven heterogeneity on the stability of the host and parasitoid population dynamics will be tested. To characterize long-term population dynamics generation-long response surface experiments will be used to parameterize joint host-parasitoid recruitment curves. These experiments will allow a test of the importance of parasitoid density for functional responses, as part of the process of parameterizing the population models. Developing these species as a model system will further the long-term goals of blending theory and experiments to understand the roles of spatial heterogeneity and nonlinearities in population dynamics and community structure, and developing novel applications of statistical methods for testing new ecological theory.