GLASSWING BUTTERFLY (Greta oto, “pearl ear” in Greek), species of brush-footed butterfly native to the rainforests of Central and South America, so named because of its largely translucent wings, which act as an unusual form of camouflage. They are hardy migrators, having been spotted as far south as Chile and as far north as Texas, and can live up to three months, a surprisingly long lifespan. The glasswing feeds on bird droppings and nectar sourced from a variety of flowers; chemical compounds in the nectar give the butterflies an unpleasant taste to predators. Their diet also furnishes the raw materials for the pheromones given off by males during their group mating behavior, known as lekking, in which they gather en masse and compete via aggressive display to attract females.
Only recently were researchers able to determine the microscopic structure accounting for G. oto’s “glass” wing. Using an electron microscope they compared the surface of the dark-colored borders of the wing to that of the transparent interior and discovered that, unlike the colored portion, which like nearly all butterfly wings is covered with densely packed light-reflecting scales (all butterfly wings require scales of some sort lest they potentially stick together when wet), the transparent portions have only a scattering of wispy, bristle-like scales, leaving roughly eighty percent of the transparent membrane exposed.