Despite its name the glass-winged butterfly (Greta oto) does not have wings made of glass, but the story behind their transparency is nonetheless fascinating.
The clear tissue that makes up the wings does not contain the colour-producing scales present in most butterfly wings. As a result, the tissue does not absorb or scatter much light, instead letting most of it pass through.
Not much light is reflected, either, due to microscopic structures on the surface called ‘nanopillars’. The nanopillars have a random distribution of sizes and positions, which means that there is a gradual transition between the refractive index of the wing and that of the surrounding air. This ensures very low reflection over a wide range of wavelengths.
The end result is that the wings appear optically transparent.
The glass-winged butterfly is found mainly in Central to South America, though it has been seen as far south as Chile and as far north as Texas.
Originally published by Cosmos as A butterfly with wings as clear as glass
Read science facts, not fiction...
There’s never been a more important time to explain the facts, cherish evidence-based knowledge and to showcase the latest scientific, technological and engineering breakthroughs. Cosmos is published by The Royal Institution of Australia, a charity dedicated to connecting people with the world of science. Financial contributions, however big or small, help us provide access to trusted science information at a time when the world needs it most. Please support us by making a donation or purchasing a subscription today.
