A central problem in biodiversity studies is determining the geographic and environmental context in which novel forms arise. Butterflies provide exceptional model systems for such studies because of the enormous diversity of wing color patterns. This project focuses on reconstructing the historical relationships and past distributions of two subspecies of butterflies that occur in eastern North America. In the southeastern United States, one subspecies has wing patterns that mimic those of an unrelated and distasteful butterfly that occurs in the same region. The other subspecies occurs in the northeast (where the distasteful model does not occur) and retains the ancestral wing pattern for this group. The two subspecies overlap and hybridize in a broad region, but away from this region the wing pattern differences are maintained. DNA sequence data from multiple genes will be used to infer the recent history of these subspecies and the origin of the current wing pattern diversity.
The proposed research examines the origin and maintenance of distinct forms and species, problems that are of fundamental importance in studies of biodiversity. It will provide information about how past climate change and current environments impact extant populations and will allow predictions about the potential effects of ongoing environmental change on future diversity. Finally, the study of natural hybrid zones is a prerequisite for determining the ramifications of hybridization for conservation policy and the protection of endangered species.
