WINDOWS ON THE WORLD

GLASSWING BUTTERFLY

If a glasswing butterfly (Greta

oto) landed on this paragraph and opened its 6cm wingspan, the text would still be perfectly readable. In their native Central America, these stunning insects are commonly known as ‘espejitos’, meaning ‘little mirrors’, although their wings are quite unlike mirrors and reflect hardly any light at all. That’s because the clear portions are scaleless and possess minuscule waxy structures called nanopillars, which are randomly arranged across the wing surface to serve as an anti-reflective coating. This adaptation may make it harder for predators to spot the butterfly, although this hasn’t yet been proven. “Butterfly wings never cease to amaze me,” says entomologist and BBC presenter Dr Ross Piper. “They do all sorts of amazing stuff. They’ve become important not just in visual displays, including camouflage and mimicry, but in thermoregulation and the release of pheromones.”