The extravagant headgear of small bugs called treehoppers are in fact wing-like appendages that grew back 200 million years after evolution had supposedly cast them aside, according to a study published Thursday in Nature. That’s probably shocking news if you are an entomologist, and challenges some very basic ideas about what makes an insect an insect, the researchers said. The thorax of all insects is by definition divided into three segments, each with a pair of legs.
In most orders, there are also two pairs of wings, one on the middle segment of the thorax and another at the rear. Other orders such as flies and mosquitoes have only one set of wings, at the rear, and a few — most ants, for example — have no wings at all. But no insects today have functional flappers in the first segment next to the head. Their forebear, however, did.
“Primitive insects 350 million years ago had wings on all of their body segments,” said Benjamin Prud’homme, a researcher at the Development Biology Institute of Marseille-Luminy in France and lead author of the study.
“We don’t know if they were all for flight, but we do know — from fossil records — that these wing-like structures were present on each and every body segment.”
Over the next 100 million years, he explained, wings on the first segment of the thorax and the abdomen dropped away entirely. But then, some 50 million years ago, something strange happened to the cicada-like tree hoppers: they once again sprouted wing-like structures from the top of the first segment of the thorax.