Genetic and peripheral visual system changes underlie evolving butterfly mate preference

Many studies have linked genetic variation to behavior, but less is known about how that variation alters the neural circuits that drive behavior. We investigated the genetic and neurobiological basis of courtship preference variation in Heliconius butterflies, which use vision to identify appropriate mates based on wing color patterns. We found that Heliconius cydno preference variation was strongly associated with genetic variation and differential expression of senseless-2 , a gene predominantly expressed in the eye. Further measurements of photoreceptor sensitivities revealed differences in inter-photoreceptor inhibition of ultraviolet-sensitive cells corresponding to courtship preference variation. Our results reveal a genetic basis for preference/cue co-evolution, suggest a link between sens-2 and visual system variation, and support the idea that changing peripheral neural computations can significantly alter essential behaviors. Summary Genetic and expression variation of senseless-2 and inter-photoreceptor inhibition predict visual mate preference in a clade of diverse butterflies. ### Competing Interest Statement The authors have declared no competing interest.