The invasion of the biting lady bug in Manitoba

They smell, bite and were clustered on building walls—inside and out—this fall. 'I could write a horror movie,' says one Manitoban.

The Asian lady beetle harmonia axyridis on thistle head

Pamela Klassen, who lives a few kilometres from Sundown, Man., in the province’s southeast, has shared her acreage with a family of bears. Deer and elk run through her property. Coyotes and wolves are known to roam the area. “Right now, I’d say I’m more concerned about the lady bugs,” Klassen says. “Everything else leaves me alone and stays out of my house.”

Lady bugs became the scourge of southern Manitoba this fall. In Klassen’s home, hundreds hide in “every nook and cranny,” under every piece of plywood and every box in the basement, even behind the sofa. By the time Klassen finished vacuuming a cloud of lady bugs from the bedroom ceiling one day last month, hundreds more came pouring out of the light fixture. “It was ridiculous. It’s terrifying,” says Klassen, 24, a horse trainer. “I could write a horror movie.”

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Entomologists will hasten to clarify there’s no such thing as a “lady bug.” The cartoonishly cute insect is actually a beetle. To avid gardeners or grain and soybean farmers, the Asian lady beetle is a welcome guest, gobbling up aphids that feast on tender green plants. But to many Manitobans this year, they’re a menace, clumping on sides of buildings, nipping at children, bleeding a foul yellow goo when threatened with a boot or a vacuum cleaner.

The province is home to 66 lady beetles varieties, and this vicious newcomer imported from Eastern and Central Asia to control aphids can range from pale yellow to orange to red. It’s identified by an M-shaped black marking and up to 19 spots, with a pronotum—the section in front of the wings—that’s more white than most native, less bothersome, species. All lady beetles have a jaw and can “take a chunk” when they bite, though this Asian species is more prone to biting than most, says University of Manitoba entomologist Kateryn Rochon, who has fielded multiple media calls from journalists surprised by the infestation reported all over social media, local papers and radio call-in shows.

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“We grow up learning lady beetles are friendly. They’re in kids’ books,” Rochon says. “You don’t have an evil lady beetle, unless it was a kids’ book for aphids.”

In the fall the bugs are looking for a sunny cliff face on which to overwinter, the insect equivalent of hibernation. But on the prairies, the closest thing to a rocky outcrop is a tall building or a barn, where they seek out even the tiniest cracks.

These lady beetles are not exactly new. They were quietly introduced to the province a few years ago, possibly through shipping, but have been intentionally released across North America as a means of biological pest control. Juveniles can eat over 100 aphids a day. They’ve also invaded New Brunswick, Quebec and Ontario at various times.

“If you have a few, you won’t notice,” Rochon says. “If there are 10,000 you will notice.”

Manitoba might have been the only place in Canada with a consistently nice summer this year and this led to a bountiful harvest. It also led to an outbreak of soybean aphids, and an explosion in their natural predators.

Queries about the harmonia axyridis were burning up the university’s Bug Line last month, says University of Manitoba entomology instructor Jordan Bannerman. He took calls from Winnipeg and surrounding areas to the southern end of Lake Winnipeg to west of Portage la Prairie. “It’s quite new for a lot of people. They’ve never experienced the onslaught of these beetles in the fall before,” says Bannerman, who pulled some 100 of the creatures from the walls of his own downstairs bathroom.

Province of Manitoba entomologist John Gavloski has seen reports of the beetle across the entire growing region of Manitoba and himself encountered soccer ball-sized clusters, and hundreds spread out across the sides of houses and outbuildings. He tells people to cover the end of a vacuum hose with a piece of nylon, suck up the beetles into the pouch and tie the end when it’s full. “Don’t knock them with a  broom,” he says. “If you damage them, they smell.”

While the benefits of the beetle in terms of the biological control of pests such as aphids are clear to growers, “the benefits in urban areas are not as obvious. There, they’re overlooked and underestimated,” he says. Other beetles—dung, ground, mountain pine, cereal leaf, bark—were on the official agenda at the Entomological Society of Canada’s annual meeting that took place in Winnipeg in late October. But the Asian lady beetles were expected to be a hot topic. “The people there would probably get a kick out of it,” Gavloski said before the event. “We might be the only ones.”