Scientists found Wasp nests that glow fluorescent green under ultraviolet light in the tropical forests of northern Vietnam. The study was published in the Journal of the Royal Society Interface. The Wasp nest looks like a hexagonal cell that was built by several species of Wasp that belong to the genus Polistes. The seal off the bottom of the hexagonal cells with silken divers made cocoon caps that protect the growing larvae within the nest. These silken cocoon caps radiate a strong greenish-yellow glow when unearthed to UV light between 360 and 400 nanometers in wavelength.
Bernd Schöllhorn, senior author, a professor of chemistry at the University of Paris, said that they are surprised to find such strongly fluorescent biomatter. The team set out to discover fluorescent insects in tropical rainforests, so they’d come equipped with UV LED torches.
The nest cocoon caps, when exposed to white light, appear bright white. Their overgrown fluorescence starts to appear under normal daylight and at night under a UV torch, and the bright green glow of the nests can be seen up to 20 meters away. Researchers compared the nests of these Vietnamese to the Amazonian rainforest of French Guiana and Wasp from temperate regions of southern France.
Researchers found that all the Wasp‘ cocoon caps exhibited fluorescent properties, although their glows varied in both intensity and the range of UV light that elicited the strongest reaction. The Vietnamese Polistes species breed during the rainy season, between June and August, when cloud cover blocks an amount of visible light from reaching the nests but still lets a fair amount of UV light slip through.