My research focuses on the ecological, genetic and developmental basis of adaptive behaviours that contribute to the evolution of new species. In particular, I am interested in how behavioural isolation evolves, and how genetic architecture and other factors may influence this process. I mostly work with Heliconius butterflies, which show a striking radiation of warning patterns across the Neotropics often associated with Müllerian mimicry. These warning colour patterns are also used as mate recognition cues and are associated with diverging preference behaviours contributing to varying degrees of assortative mating. I have previously demonstrated that the genetic loci underlying divergent mating preferences and their colour pattern cues are physically linked in the genome, which should facilitate speciation with gene flow. A major ongoing project concerns the nature of these associations as well as the genetics of behavioural isolation in Heliconius butterflies more broadly.

Merrill, R.M., et al. (2015) The diversification of Heliconius butterflies. What have we learned in 150 years? Journal of Evolutionary Biology. 28:1417-38 Merrill, R.M, Wallbank, R.W., Bull, V., Salazar, P., Mallet, J., Stevens, M. & Jiggins C.D. (2012) Disruptive ecological selection on a mating cue. Proceedings of the Royal Society B. 79: 4907-4913. Merrill, R.M., van Schooten, B., Scott, J.A., & Jiggins, C.D. (2011) Pervasive genetic associations between traits causing reproductive isolation in Heliconius butterflies. Proceedings of the Royal Society B 278: 511-518.