Like something straight out of a horror movie, a catastrophically large swarm of mayflies plagued the Mississippi River Valley area last week, leaving a mess in its wake that actually caused a car accident.
The annual Mayfly hatch began on the evening of June 20 and immediately began swarming towns up and down the Mississippi River. So large was this year’s hatching that it actually showed up as a minor rain squall on the National Weather Service’s radar. After a little over an hour, the seemingly plague-like swarm died down, but left a massive, slimy mess.
This year’s Mayfly hatch was so bad that it caused a three car accident. The road had become slick with the little bugs. Visibility on the road was also poor, because the monstrous cloud of insects was so dense. The combination of these poor driving conditions caused at least one driver to lose control of her vehicle.
The accident injured two people who were taken to a nearby hospital.
On the upside, the annual terror never lasts long. After spending the vast majority of their lives as nymphs in the river, they emerge sometimes in small batches, or in freakishly large clouds other times. Females then fly through crowds of males, who seize them so that they can mate with them. The females then return to the river to lay their eggs and die. The males die about a month later.
On the downside, all of those dead Mayflies leave a pretty big mess. Last year’s Mayfly hatch forced the Minnesota Department of Transportation to bust out their snowplows so that the heaps of Mayfly carcasses could be removed from the highways.