CHICAGO — As Chicagoans take to the lakefront and open their windows after a long winter, they’re being greeted by an especially noticeable annoyance: swarms of midges.
Small flies known as midges have been hatching en masse from the lakefront in recent weeks, causing swarms and blanketing nearby windows and balconies.
The insects are seasonal and are usually seen this time in the spring, when they hatch from bodies of water including Lake Michigan. But this year has been especially productive for midges, said Allen Lawrence, associate curator of entomology at Peggy Notebaert Nature Museum.
“This year seems to be a good year to them,” he said. “We’re not exactly sure why.”
Lakefront neighbors have certainly noticed this year’s population of midges. They’ve taken to social media to ask about the midges or to post in frustration after being coated by the bugs.
“They were so bad over the weekend it was almost biblical,” one person on Reddit posted in response to a Chicago resident’s photo of midges crawling over a window screen. “Huge swarms of them just surging outside my windows.”
Midges, known scientifically as chironomids, are an aquatic insect that live and mate near bodies of water. Their larvae live underwater or in wet mud and hatch every spring.
The species is prominent in the Great Lakes area. They are sometimes confused for gnats or mosquitos.
It is prime midge hatching season, Lawrence said.
The male midges hatch first and rise from the water into swarms, Lawrence said. The females hatch later and fly into the swarms to mate before laying larvae in water sources.
Midges have a lifespan of about 3 to 11 days. Favorable conditions have led to a more successful hatching season this spring, and the cool climate and abundant food sources could keep the midges alive for longer, Lawrence said.
Factors like cool temperatures plus a lack of disease and predators could be the reason for the extra noticeable swarms this season, he said.
“You’ll find them everywhere” during the mating season, Lawrence said. “My window is covered with them even though it’s raining.”
Peak mating season will likely be over by the end of next week, Lawrence said.
Until then, they’ll continue to be a nuisance for lakefront goers. Neighbors like Rogers Park and Edgewater have especially seen large swarms this spring.
“I can’t even take a stroll and talk with a friend without almost swallowing a fly every few feet!” one woman wrote in a Rogers Park Facebook group. “I don’t remember them being this bad at the end of last April.”
“My husband and I thought we saw smoke coming from a rooftop and then discovered it was just a really dense swarm,” one person replied.
The insects do not bite and are not otherwise harmful, Lawrence said. In fact, the midges play an important role in the local ecosystem. They are a popular food source for some of the city’s favorite lakefront dwellers.
“They’re pretty well-timed,” Lawrence said. “We’re heading into peak bird migration now and midges are a nice bird snack.”
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