Io Moth

Automeris io is one of about 130 species in genus Automeris, the New World 'io moths.' The species is widespread across eastern and central North America, from southern Canada through the Gulf states and into northern Mexico. Adults exhibit dramatic sexual dichromatism: males have bright yellow forewings, females have rust-red forewings; both sexes have hindwings carrying enormous blue-and-black eyespots that resemble the eyes of a vertebrate (specifically, a small predator) when revealed. The defensive strategy is one of the textbook examples of 'flash coloration' in Lepidoptera: at rest, the moth holds her cryptic forewings forward, completely covering the dramatic hindwings — she resembles nothing more than a dead leaf or a piece of tan tree bark. When approached by a bird or other visual predator, she snaps the forewings forward to expose the hindwing eyespots, often combined with rocking the body up and down. The startle response in the predator buys the moth enough escape time. Caterpillars are bright green with rows of toxic urticating spines that release a histamine-like venom on contact — brushing against an io caterpillar produces a painful red welt comparable to a wasp sting and lasting several hours. Caterpillars feed on a wide range of trees and shrubs (over 100 host species documented). Adults, like all giant silk moths, have no functional mouthparts and live 4-7 days.