It’s almost that time of year again, when going for a walk on a sunny day might just mean walking into a swarm of black gnats.

These gnats, known as midges, are often found in Ontario's lakeshore, wildlife areas and parks. Most years, they begin to appear in early springtime and last throughout the summer before dying in the fall.

Doug Currie, a professor in the Department of Ecology and Evolutionary Biology at the University of Toronto, said they’re a small price to pay for a healthy ecosystem.

“Just think, if they were to disappear, that would be a warning that things aren’t quite that great,” Currie said about the bugs on and near Lake Ontario. “So I think that given what a short period that they’re out, is a small price to pay for a clean lake.”

That’s because midges can tell us a lot about our ecosystems, he said. Midges, when highly populated above bodies of water, are an indication of healthy water with regular oxygen levels. When absent, they point to pollution in the water.

In addition, adult midges get eaten by larger insects such as spiders and swallows.

Monthly, in the spring and summertime, new species of these bugs will appear. There are over 4,000 species, all of which emerge in swarms as a way of mating.

“When you get these large swarms, it’s actually a mating ritual,” Currie said. “And so they need to connect with each other to mate.”

The large swarms are usually male midges that group together to attract females. After mating, Currie says that the cycle begins again.

“[They’ll] go off and mate, and then the cycle begins again. [They lay] their eggs on the lake or the street, and then the cycle begins again.”

Most of the species seen in Ontario do not bite, however the ones that do are females as they need protein to mature their eggs.

Currie says that they do not bite, and that there isn’t a surefire repellent against them.

“They’re certainly innocuous creatures,” he said