Photo: dapawprint (Flickr)
Have you ever walked into a swarm of insects–gnats, mosquitoes, or one of their many cousins–and then found yourself unable to shake the swarm? You fake left, go right, but the little buggers still hover above. As if it that weren’t bad enough, did you know your head had just become the happening scene, where every hip gnat wants to be–in other words, the insect world’s equivalent of a singles bar?
That’s right, swarms are places for the sexes to meet and greet. The first time an entomologist reported the purpose of swarms was in 1906. Frederick Knab wrote that he’d netted 901 mosquitoes from a swarm, but only 4 were females!
Here’s how Knab explained it: males gather around some landmark–a cornstalk, perhaps the head of an unsuspecting human–and wait for eligible females. When a female enters the swarm, the males immediately pick up her flight tone, which is different from theirs. Coupled with one lucky guy, she flies to some protected place to mate.
After their interlude, the female goes to lay her eggs, but the male returns to the swarm, on the outside chance that he’ll get lucky once more. That’s why Knab netted so many more males than females.
Sometimes, these gatherings get quite large. In Germany, in 1807, people saw a huge cloud of smoke billowing over a church. So they called in the fire brigade, only to realize that the dark cloud was actually a swarm of gnats who’d picked the church steeple as their rendezvous.