Meeting Abstract

P2.60A  Saturday, Jan. 5  Sexual dimorphism and species divergence following UV opsin duplication in Heliconius butterflies MCCULLOCH, KJ*; BRISCOE, AD; University of California, Irvine; University of California, Irvine mccullok@uci.edu

Butterflies are known to have some of the most spectrally diverse photoreceptor types in the animal kingdom. The genus Heliconius is of particular interest because it represents an adaptive radiation in which many species have formed Müllerian mimicry rings throughout Central and South America. Species of this genus have a duplication of a UV opsin gene typically expressed in short wavelength photoreceptor cells (R1 and R2 cells). However nothing is known about the spatial expression pattern of short wavelength opsin proteins in the compound eyes of species with the duplicated gene. We used immunohistochemistry to fluorescently label cryosections of compound eyes with UV opsin-specific antibodies. The UV1 and UV2 opsins of seven species in the genus Heliconius were labeled, representing all major clades in the phylogeny. We reveal strikingly different spatial expression patterns among species in different branches of the Heliconius phylogenetic tree. We also observe unexpected sexual dimorphism of opsin expression in a majority of the species we examined. These results suggest the strength of natural and sexual selection shaping the compound eye has varied considerably over the evolutionary history of the genus. Further genetic, molecular, and physiological analysis may inform us how complex traits such as visual systems play a role in the early divergence of species.