The Grooviest Cocoons in the Insect Kingdom

Larvae of some paper wasp species use mysteriously fluorescent silk to weave the container in which they mature to adulthood.

Adult paper wasps are capable builders, painstakingly mouth-crafting nests out of plant matter and spit. But they start out as larvae which carry out construction projects of their own. Just before these youngsters begin a metamorphosis into maturity, most paper wasp larvae sequester themselves in special nest compartments with woven seals called cocoon caps, which they make out of silk threads. There on the cusp of adulthood, the larvae may add a bit of dorm room flare. The cocoon caps of several paper wasp species, relatives of some you may see in your yard, fluoresce yellow-green under ultraviolet light and lend the whole nest a groovy glow.