Dissertation Research: The Role of Hybridization in the Evolution and Diversification of Heliconius Butterflies

University Of Texas At Austin, Austin TX

Investigators

Abstract

One of the primary goals of evolutionary research is to explain the mechanisms by which new species originate. One such mechanism that has received relatively little attention is the formation of new species due to interbreeding between previously established species (or, speciation via interspecific hybridization). In an effort to understand how new species originate due to hybridization, this project will trace the history of divergence between Heliconius pachinus, a tropical butterfly species that recently originated via hybridization, and one of its parental species, H. cydno. It is hypothesized that since the origin of the H. pachinus form, natural selection has led to the evolution of mechanisms by which species integrity is maintained. This project will determine how much overall genetic exchange is occurring between these two species by examining these mechanisms and by comparing the genetic makeup of both species throughout their range. Although the role of hybridization in animal evolution is receiving more attention than ever, there are few clear examples of speciation via hybridization in animals. Once finished, this study will provide one of the most complete explanations of speciation via hybridization. Furthermore, the mechanism of divergence proposed here is a novel and exciting process by which speciation may have occurred many times in this genus and others. The incredible correspondence of mimetic Heliconius species pairs has long amazed biologists and still lacks a mechanistic explanation. The hypothesis put forward here could well be the explanation for this entire phenomenon.