The Role of Ecological Interactions in Diversification: Rates of Habitat Shifts and Within-Habitat Diversification in the Enallagma Damselflies of Two Communities

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9419318 McPeek Our ability to steward the world's biological diversity depends on our understanding of the processes that generate and maintain biodiversity in different ecological settings. This research explores the importance of evolutionary processes in affecting biodiversity patterns in different habitats for a group of aquatic insects, the Enallagma damselflies (Odonata: Coenagrionidae). Some Enallagma species are found only in fishless water bodies. Furthermore, 3-4 times more species exist in habitats with fish than in fishless habitats. Aspects of the physical environment, the major prey, and major predator species that coexist with various Enallagma species will be identified and used to evaluate how these aquatic communities vary across the southeastern USA. Also, a phylogeny for most of the North American Enallagma will be developed using modern molecular DNA techniques. Statistical techniques developed to test for differences in diversification rates will be applied to evaluate whether the differences in the number of species between the two lake types can be explained by speciation and extinction in the group. Along with addressing basic questions about diversification into multiple habitats, this study has important implications for the conservation of biological diversity. Most effort for conserving species is directed at the processes leading to extinction, because of extinction's immediate and irreparable impacts. However, in the longer term an understanding of how conservation practices influence the continued evolution and diversification of taxa is needed to preserve functioning ecosystems and the abilities of species to respond evolutionarily to long-term environmental changes. By studying how ecological conditions influence diversification, this research will provide initial data to evaluate how properties of ecological settings may influence the continued evolution of taxa.