Ecology and Evolutionary Biology, University of California at Irvine, USA
Heritable phenotypic variation is the “raw material” of evolution by natural selection, and understanding the mechanisms that generate such variation has become a fundamental challenge for contemporary evolutionary biology. In recent years, evolutionary developmental biology has encouraged a change of focus from the sorting of phenotypic variation by selection to the production of that variation through development. The colour patterns decorating butterfly wings provide ideal material to study the reciprocal interactions between evolution and development in this process. They are visually compelling products of selection, often with a clear adaptive value, and are also amenable to a detailed developmental characterization at different levels. We studied different aspects of the process of generation of variants in Bicyclus anynana eyespot patterns. Results will be discussed of experiments where we have used artificial selection to explore the potential for changes in eyespot size phenotypes, which were thought to be constrained by the properties of butterfly wing pattern development. We also report on experiments aimed at identifying the actual genes involved in the response to selection. Our results show that a combination of approaches from evolutionary and developmental biology used to study the patterns of colour on butterfly wings can greatly contribute to understanding how evolutionarily relevant variation is generated.