Mating preferences act independently on individual elements of visual signals inHeliconiusbutterflies

Abstract

AbstractMating cues are often comprised of several elements, which can act independently, or in concert to attract a suitable partner. Individual elements may also function in other contexts, such as predator defence or camouflage. InHeliconiusbutterflies, wing patterns comprise several individual colour pattern elements, which advertise the butterflies’ toxicity to predators. These wing patterns are also mating cues, and males predominantly court females that possess the same wing pattern as their own. However, it is not known whether male preference is based on the full wing pattern or only individual pattern elements. We compared preferences of maleH. erato lativittabetween female models with the full wing pattern and those with some pattern elements removed. We found no differences in preference between the full wing pattern model and a model with pattern elements removed, indicating that the complete composition of all elements is not essential to the mating signal. Wing pattern preferences also contribute to pre-mating isolation between two otherHeliconiustaxa,H. erato cyrbiaandH. himera, therefore, we next compared preferences for the same models in these species.H. erato cyrbiaandH. himerastrongly differed in preferences for the models, potentially providing a mechanism for how pre-mating isolation acts between these species. These findings suggest that contrasting levels of selective constraint act on elements across the wing pattern.