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Photos of midges taken outside a condo window in downtown Toronto.Chris Manza

Near many a great or small Canadian lake or river, there is likely a Hitchcockian swarm of insects that will bring out the irrational side of bystanders: the frantic hair-mussing, head-clopping or profound expectorations.

A few mindful cyclists may wear forbidding headwear that makes them look like they're geared up for an early episode of Battlestar Galactica.

Emerging from the edges of lakes, slow-moving rivers and stagnant pools, the mosquito-like menaces fly, mate and die within a week.

In the meantime, humans suffering from annual entomological amnesia are reminded of the culprit's name – the non-biting midge – and wonder if its population has grown since the previous year.

While there is no census data available – short- or long-form – one of Canada's leading pest-control companies has already noticed an uptick thus far.

"We're seeing an increase in complaints since last year around this time," said Alice Sinia, an entomologist with the pest-control giant Orkin. "We're basing that on calls and complaints. We don't have enough data yet. It's very early in the season."

Dr. Sinia attributes the growth to increased precipitation over the past summer and winter. "It always goes back to breeding area – is there more habitat for the larvae?" she said.

Toronto, she pointed out, had a rain-filled summer and snow-heavy winter, which means more moist soil and stagnant pools come spring. "When the snow starts to melt, there is more debris from winter and more decay, which creates a perfect breeding ground for the larvae," she said.

Peak complaint month across the country is May, and the number of reports remains relatively high until September.

One of the insect's more infamous moments came seven years ago during a baseball playoff game in which the Cleveland Indians – who play near Lake Erie – hosted the New York Yankees. An intense on-field infestation led to hand-waving and mitt-slapping. When asked to speculate after the game on what exactly had descended on the diamond, Yankee shortstop Derek Jeter refused to take an educated guess. "I'm not an expert on what kind of bugs they are. They were small."

The most intense swarming takes place near lakes, where several hundred chironomidae can cram into one square metre of airspace. The wind can blow these clouds of insects further inland. To the naked eye, they may just look like a bunch of useless bugs set out to annoy people, but if you were to swat at them, you'd be interrupting some important business time: Males congregate in massive groups, and the females fly into them to mate.

"Basically a waterfront orgy is going on," said Doug Currie, senior curator of entomology at the Royal Ontario Museum. "If you can bat them down, you'll see a lot of mating going on. End-to-end or back-to-back."

Males, he said, have feathery antennae and females have slender antennae. Unlike mosquitoes, the non-biting midge doesn't have a long proboscis.

The chironomid is one of the more benign species in the midge family. Prairie provinces, for example, face the summertime scourge of the wheat midge, which causes severe damage to crops. In the United Kingdom, there is the threat of the female Scottish midge; one millimetre in length with a wingspan of less than two millimetres, this nearly imperceptible predator smells human carbon dioxide on our breath and bites, sometimes with thousands of their friends.

By contrast, the non-biting midge is merely a nuisance. The chironomid is attracted to light, so light traps are an effective countermeasure: They draw the bugs in and zap them. Otherwise, homeowners can minimize the brightness of their outside lights or use yellow bulbs. The insects can also penetrate vents, so best to install screens with tiny holes.

But Dr. Currie said we should take solace from the presence of the non-biting midges. Part of the food chain, they're good for the ecosystem: Fish and frogs eat them. And if you happen to swallow a glob of these distant relatives of the arthropod, don't sweat it. They're like micro-crustaceans. "Heck, we eat lobsters and crabs with relish," Dr. Currie said. "And people now eat bugs because they want to. "