Great Southern White Ascia monuste

This butterfly is the only species in its entire genus—it alone carries the evolutionary weight of its whole genus on its wings. But here's where it gets truly surprising: females come in two dramatically different color forms, light and dark, so different that early naturalists thought they were completely separate species. This sexual dimorphism is a striking example of nature's diversity.

Found from the Atlantic and Gulf coasts of North America all the way to Argentina, this champion long-distance migrant undertakes remarkable seasonal journeys across thousands of miles. With continental range, extreme sexual dimorphism, and a genus all to itself, this is a butterfly that defies convention at every turn.