Outlined in the rays of the low angled sun of dawn or dusk, they gather to fly, sing, dance, find love and die. These crepuscular partygoers are known as midge flies and they gather into compact mating swarms this time of year. Chances are youve accidentally blundered into one of these swarms and found yourself waving your hands in desperate arcs to rid yourself of this pestilence. Equally as likely, a few may have found their way into your mouth and you werent open to trying new protein sources. Either way, the experience was momentary.
As proof that even the humblest of Gods creatures are worthy of a second glance, I invite you to ponder these midges for a bit longer next time. Spit em out and stop to take a closer look.
There are some 2,000 kinds of midges. They are actually tiny members of the Fly clan (Diptera) a diverse group of insects which include house flies, deer flies and even mosquitoes. Unlike the aforementioned, however, our local midges do not bite humans. In fact, they dont bother to feed- period- once they come out into our world.
They do all their eating as aquatic larvae. Living within slime tubes pasted onto the surface of rocks and water plants, they feed on tiny bits of plant material that drift by. While in this stage, they are food to fish, dragonfly larvae, crayfish, and just about everything else. After this brief period of supporting the aquatic food pyramid, they emerge to become flying adults. As denizens of the air, the predatory onslaught continues from aerial predators. Its tough being the perpetual cuisine du jour, so who can blame them for abandoning all thoughts other than love once given the chance.
Today I pondered a bunch of these dancing love flies. There was a big hatch on the River Raisin this afternoon. Swallows of all description were swooping about and feasting on newly emerging adult midges. Barn, Cliff, Rough-winged, and Bank Swallows were coursing up and down the river just above the water surface in an ecstasy of consumption. Having already eaten, I just stood on the bank and watched a small cluster of flying midges.
Midge swarms can contain millions of individuals. I have witnessed groups so large (over some of our coastal marshes) that they looked like plumes of smoke rising from an unseen fire. Todays swarm was much more modest Id say about 50 insects. They clustered together in a ball about a foot from the ground and maintained their position despite wind gusts. Midges focus on so-called markers in order to keep their position. In this case, it was a lone limestone rock sitting slightly higher than the rest. Often, we become the markers, by the way, which is why they seem to follow us like campfire smoke.
These mating swarms are all male affairs. I took a few swipes at the masculine cloud and came up with two or three stunned little individuals. They had the large bushy antennae that identify their sex (large being a relative term here since the creatures are only a couple of millimeters long). As the rest of the cloud resumed its shape, the little guys in my palm recovered and flew off to join their stag group. Although I couldnt hear it, I know that the whole cloud was emitting a low buzz caused by the rapid beating of hundreds of tiny wings.
The female midges are attracted by this hmmm and eventually dart up from the grass below and join up with one of the males. The couple mates while on the wing and she then drops out. Eventually she lays her eggs in the water and the cycle of life is complete. No females came while I was there, but I have the feeling it was because I was there (better door than a window kind of thing).
The one last thought to ponder regarding these amorous little flies is why they gather into such large groups in the first place. With predators swooping all about, it seems that such a tactic would be dangerous. As it turns out, a large swarm insures greater protection from flying predators. The chances of any one individual being eaten are greatly reduced when there are a whole lot of them.
On the other hand, researchers have found that smaller swarms provide the best chances for mating to occur. So, the male midge has one final life decision to make during his brief life: Does he chose a short lustful life with the small swarm or fall back to a longer life of chastity with the large swarm? Faced with this difficult choice, they ponder their lot, as we ponder them, and we both say Hmmmmmmmmmmm.