The complicated geographical variations in color pattern within species of Heliconius butterflies have piqued the interest of biologists for more than a century. The advent of simple molecular biological techniques has provided researchers with a new source of data to interpret these patterns, including the complex array of mimetic forms which have defied explanation till now. A survey of intraspecific variation in DNA of Heliconius species will provide an independent hypothesis of the history of colonization and divergence among the geographical races within each species. Under the guidance of faculty sponsor Richard Harrison, graduate student Andrew Brower will collect butterflies in South America and then conduct laboratory analyses of morphological and molecular features of these samples. The data will contribute to distinguishing between two major explanations for the patterns of wing color patterns: allopatric divergence during the Pleistocene, or parapatric divergence due to natural selection across narrow ecological clines. As well, the study will advance modern attempts to disentangle historical, phylogenetic causes of change from current ecological adaptations that also lead to change over short time spans.
