Glasswing Butterfly Uses Nanostructures for Transparency

Greta oto, a species of brush-footed butterfly most commonly found in Central and South America, has a colloquial moniker just as beautiful as its physiology: It’s known as the “glasswing butterfly.” And that name is definitely not hyperbolic. Because these butterflies’ wings look enough like glass to make it seem like they belong on a cathedral.

The glasswing butterfly, which can be found as far south as Chile and, very rarely, as far north as Texas, belong to the family, Nymphalidae. Nymphalidae are the largest family of butterflies with more than 6,000 species distributed throughout most of the world. The glasswing stands out as unique for obvious reasons.

The glasswing butterfly uses waxy nanopillars to make its wings minimally reflective.

The glasswing butterfly. David Tiller 

The glasswing, shown off in the PBS video above (via Laughing Squid), is able to achieve its extraordinary transparency thanks to its wings’ lack of pigment, as well as their being covered with waxy nanopillars. The nanopillars allow Greta oto‘s wings to avoid being reflective. The nanopillars (shown below), are randomly arranged on the wings’ surfaces, and are so tiny that their radii are smaller than the wavelengths of visible light. This nanoscale allows the miniature pillars to scatter light rather than have it reflect off the transparent wings.

The glasswing butterfly uses waxy nanopillars to make its wings minimally reflective.

A close-up look at the glasswing’s waxy nanopillars. PBS

Despite the fact that the glasswing may seem like an especially fragile member of Nymphalidae, it’s shockingly resilient. Apparently the glasswing is able to carry 40 times its own body weight, and also combats predation by birds by eating toxins that make the butterflies taste foul. The natural nanotech still takes the cake for cool factor, however, especially because it’s reminiscent of vantablack.

What do you think about the glasswing butterfly? Is this the most stunning butterfly you’ve ever laid eyes on, or are you a bigger fan of these boozed-up specimens? Give us some clarity about what you’re thinking in the comments!

Feature Image: Deep Look