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Asian Ladybugs Come Out in Large Numbers, but Come in Peace
Asian ladybird beetles take up residence in a windowsill in the Annex. Photo by Torontoist reader @michalhay.
If you’ve spent today warding off swarms of insects that don’t look quite like regular ladybugs, don’t be alarmed: they’re just Asian ladybird beetles, and they’re trying to make the most of an atypically warm fall day.
“They’re looking for a place over winter,” Mark Fitzpatrick, an assistant professor at U of T’s Scarborough Campus Department of Biology, explained to Torontoist. “And today’s a warm day, giving them lots of energy. So they sparked up today and they’re looking for cracks and crevices to spend the winter…That’s why they end up in your windowsills and up in the corners of walls and stuff like that.”
According to Fitzpatrick, Asian ladybird beetles (or Harlequin Ladybirds, or Harmonia axyridis) were an introduced species, coming to North America via the southern United States, first in the 1900s and again in the 1980s—and the latter batch is the most likely of the two to have made it all the way up here. If you look on their pronotum (which is a shield over their thorax, though “most people confuse it as the head because it’s black and white and kind of looks like eyes but if you look underneath it you can see they have a tiny little head”), “it seems to have—depending on which way you look at it—what looks like an ‘m’ or a ‘w’ on it,” Fitzpatrick said, “which our local ones don’t have.”
There’s little risk of any danger to humans from the beetles, with Fitzpatrick saying that a small bite and minor allergic reaction are the “worst I’ve heard.” The bugs are reluctant to bite anyway, as Fitzpatrick discovered himself earlier today: “I had my lunch outside today on the campus, and I must’ve seen hundreds of them. They were landing on me like crazy.”
The beetles, said Fitzpatrick, “are good at controlling pest insects. They’re just, unfortunately, prolific breeders, and they like our winters.”