Wasps build fluorescent nests, but why?

A team of scientists say they encountered the first known instance of animals building fluorescent houses. In a new article, they detail the search for nests built by certain species of wasps that glow green under exposure to ultraviolet light.. Additionally, related wasps in other parts of the world also appear to be able to create equally strange structures.

The discovery happened on an expedition to northern Vietnam, but not intentionally, scientists say. Author of the study Bernd Schöllhorn, professor of chemistry at the University of Paris, Recount Live Science that they traveled with UV lights in hopes of stumbling upon fluorescent bugs when it gets dark. Instead, they found wasp nests with cocoon caps (silk-woven structures that plug the nest and protect the larvae) that gave off a shine, poo color glow when exposed to UV light between 360 and 400 nanometers in wavelength at night. Like any good researcher, they brought samples back to the lab for further study.

“We were very surprised to find such a strongly fluorescent biomaterial,” Schöllhorn told Live Science. “To our knowledge, this phenomenon has not been observed in the past, neither by scientific researchers nor by photographers. ”

All the bright nests they found belonged to species of the wasp genus Polistes, also commonly known as paper wasps. When they got nests from two other Polistes species living in the Amazon rainforest and in France and subjected them to UV light, they found that these nests also glowed, although all the nests had a slightly different intensity and color from each other. The team’s findings were published this week in the Journal of the Royal Society Interface, and pictures of the various light-up nests can be seen here in their additional material.

Although shining under black light can be considered an exotic trait, scientists have discovered a growing list of creatures from different branches of life which have this unexpected ability, including mammals. But they are still trying to figure out the reasons why fluorescence should be developed in the first place. The fluorescent nest can help wasps get home, for example, or allow them to distinguish one nest from another. It can also help the development of larvae, since the glow could act as a substitute light source during rains season. It may even be an accessory or vestigial trait that never had a goal, or at since lost its function but remains present because it does not disadvantage wasps.

Researchers plan to continue studying these wasps and their glowing homes, in order to unearth the chemicals that make them fluorescent. From there, they hope to find out if these ingredients could have an application in humans, as a new fluorescent marker for research or medical imaging.