BURLINGTON, Iowa.—An eastern Iowa town was blanketed in bugs on Thursday night.

A mayfly hatching on July 2 sent bugs everywhere.

Photos from Burlington, Iowa show cars and gas stations covered in the flying insects that emerge annually in a large hatching event.

According to research conducted at the University of Notre Dame, mayfly larvae come out of bodies of water and shed their skin to become full mayflies and then, in one large exit, a swarm of the insects fly away.

Researchers at Notre Dame, the University of Oklahoma, and Virginia Tech used the same radar technology that meteorologists use to count the number of mayflies that emerge annually from both the Upper Mississippi River and the Western Lake Erie Basin.

Over the span of eight years, researchers estimated that up to 88 billion mayflies can swarm each location annually.

Researchers also found that there was a more than 50 percent decrease in population of mayflies from 2012 to 2019 and other studies have linked the drop in mayflies to declining water quality.