Ladybugs are the rarest of insects in that people actually enjoy having them around. But residents of the Ottawa Valley should brace for an invasion of a particularly annoying variety of the creatures this summer. Warmer weather is expected to bring large numbers of the Asian ladybug to the area, attracted by the soy and canola fields that surround Ottawa, says Jeff Dawson, associate professor at Carleton University’s department of biology. And here’s the thing: they bite.
The orange-and-black beetles live in large swarms and have been known to take nips out of people’s skin. It’s not that they’re out to get humans. “Their nervous system tricks them into thinking [you] might be an aphid or a food substance so they take a little bite,” Dawson explains, noting that once the bugs realize a person is not edible, they move on. But by then they’ve left an itchy red mark on the skin.
Though the bugs are effective at eating aphids, a common pest in many crops, the species is both a nuisance and a threat. Dawson says biologists worry they are displacing native ladybugs. “Species extinction causes loss of diversity, and for ecosystems to be healthy we want lots of diversity, lots of different species,” he says.
Asian ladybugs first showed up in North America about 30 years ago on ships docked at U.S. ports, but also as part of a campaign by agricultural managers to battle aphids. With no natural predators, the ladybugs are sure to annoy many Canadians this summer. But if people are tempted to retaliate, Dawson warns, “don’t crush them.” The bugs will leave a nasty stain and release a foul odour that’s been compared to “rancid peanut butter.”