VPW: Effect of Intraspecific Variation in Plant Quality on the Population Structure of Herbivores (Population Biology)

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The adaptation of populations to environmental change can occur at extremely fine scales. Plants growing on heavy-metal soils can be genetically differentiated from neighboring plants growing only meters away on normal soils. Such genetic isolation is the result of strong selective pressures by metals in the soil coupled with selection for reduced gene flow between plant populations that span mine boundaries. In this proposal, it is asked whether the same processes that have given rise to population differentiation in plants can also cause differentiation in herbivore populations that use these plants. The importance of herbivore mobility, feeding specialization and exposure to metals to the presence or absence of local adaptation will be examined. Eight different insect species (4 specialist feeders and 4 generalists feeders - with difference dispersal abilities) that occur on plants both on and off mine tailings will be selected. Egg progeny of female insects, from both mined and normal sites, will be collected for each species. Eggs from these females will be split into two batches: one batch will be placed on plants growing on heavy-metal soil while the other will be placed on nearby plants growing on normal soils. Such reciprocal transfer experiments will allow determination if progeny from insects collected on metal soils fare better than progeny of insects collected from normal soils on metal-contaminated plants. If this is the case, then local adaptation has occurred. If herbivores capable of using metal-containing plants are genetically-differentiated from those on nearby plant populations, then it is possible that herbivore populations in general may exist as patches of locally-adapted individuals that are responding to small scale changes in plant quality. This project furthers VPW program objectives to provide opportunities for women to advance their careers in science or engineering through research, and to encourage other women to pursue careers in these areas through the investigators' enhanced visibility as role models on the host campuses. In this project, the proposed activities which contribute to the second objective include: teaching two courses, Evolutionary Ecology, and a seminar in the History and Role of Women in Science; giving lectures on personal research in the departmental Entomology and Plant Science seminar series; collaborating with a phytochemist and evolutionary ecologist in the Entomology department.