Müllerian mimicry in two species of Heliconius butterflies

    Both species are unpalatable to birds, and advertise their unpalatability with striking wing patterns. Where both species are relatively rare, each gains an advantage by mimicking the other so that predators learn (often after only a single encounter) to avoid similar patterns in either species. Multiple localized morphs occur in both species, so that opportunities for predator learning are increased. Contrast this with Batesian Mimicry, in which a palatable species mimics an unpalatable model.

    Müllerian mimicry has long been recognized in many species. The genetics of the phenomenon has only recently been studied. In Heliconius spp., alleles responsible for components of the warning pattern originated in one species and were transferred to the other by hybridization.