May 4 (UPI) -- Chicago residents have reported an unusually large swarm of gnats overtaking the city, but experts said its a natural phenomenon and nothing to be worried about.
The insects, also known as chironomid midges and non-biting flies, are common in the region during the springtime, but experts said this year's population is unusually large.
"This is a natural phenomenon," Allen Lawrance, associate curator of entomology at the Peggy Notebaert Nature Museum, told NBC Chicago. "We'll see big emergences of them from time to time, but this year, we're definitely seeing a lot of them so it is a little bit unusually large, but it's not the end of the world times or anything like that."
Lawrence said researchers are not yet sure what caused this year's large swarm, but populations can be affected by factors including weather and viruses, as well as the presence of predators such as fish, dragonflies and migratory birds.
He said the large swarm is unlikely to last long, as gnats typically live for only 3-11 days.
"You will never have them completely go away," he said. "But we should get past this huge swarm at some point pretty soon here."