Adaptive introgression of a visual preference gene

Abstract

Visual preferences are important drivers of mate choice and sexual selection, but little is known of how they evolve at the genetic level. Here we take advantage of the diversity of bright warning patterns displayed byHeliconiusbutterflies, which are also used during mate choice. We show that twoHeliconiusspecies have evolved the same visual mating preferences for females with red patterns by exchanging genetic material through hybridization. Extensive behavioral experiments reveal that male preferences are associated with a genomic region of increased admixture between these two species. Variation in neural expression ofregucalcin1, located within this introgressed region, correlates with visual preference across populations, and disruption ofregucalcin1with CRISPR/Cas9 impairs courtship towards conspecific females, proving a direct link between gene and behavior. Our results support a role for hybridization during behavioral evolution, and show how visually-guided behaviors contributing to adaptation and speciation are encoded within the genome.