9632154 Boecklen Over the past twenty years, the study of hybrid zones has grown from a backwater of systematics to one of the most dynamic areas in evolutionary biology and ecology. Hybrid zones are centers of genetic diversity, and so represent ideal experimental systems in which to investigate evolutionary processes, including natural selection and interactions between hosts and parasites. Despite the renewed interest in hybrid zones among ecologists, the influence of hybrid zones on plant-insect interactions is poorly understood. The proposed research will examine hybrid zones of Madrean and Southwestern oaks, and will use a combination of biogeographic, molecular genetic, and field experimental approaches to investigate the effects of host plant hybridization on herbivore population dynamics and community structure. In addition, the influence of plant hybridization on the outcome of antagonistic interactions between endophytic fungi and interactions between endophytes and herbivores will be tested using field inoculations of fungal species onto oak hosts. The proposed research will contribute to our understanding of plant-herbivore interactions, and will help identify factors that influence plant susceptibility to herbivore attack. By understanding how herbivores respond to genetically novel host plants (i.e, hybrids), results of this research will provide important insights into developing new strains of pest-resistant crop plants. In addition, the results of this research will provide background data on the potential use of endophyte fungi as biocontrol agents against insect herbivores.
