Fall infestation of ladybug lookalike blamed on summer without a drought

'Scott' the cat shares the warmth of the sun with a swarm of Asian lady beetles at Natalie Rowe's farm. (Stu Mills/CBC - image credit)
'Scott' the cat shares the warmth of the sun with a swarm of Asian lady beetles at Natalie Rowe's farm. (Stu Mills/CBC - image credit)

People across eastern Ontario are hoping they've seen the end of an invasion of ladybug lookalikes

The Asian lady beetle, Harmonia axyridis, which closely resembles a ladybug, spends its summer dining on hundreds of soft insects, or aphids, in corn and soybeans crops until the harvest.

That's when temperatures begin to drop, causing widespread panic in the beetle population that leads to their eviction. This year, though, there was a hot lady beetle summer.

"They had a good year, there was no drought and there were lots of aphids," said Hume Douglas, a research scientist with Agriculture and Agri-Food Canada.

"At the end of this good year, they don't want to die. They want to survive the winter by getting somewhere sheltered."

Fittingly, for an insect that has also been called the "Halloween Beetle," the lady beetle can wear many costumes yellow to red to black, and can have anywhere from zero to 20 spots.

Hume said the only sure way to distinguish the insect from a ladybug is to look for a white "W" or "M" on the pronotum, the area on the insect's back just behind the head.

Stu Mills/CBC
Stu Mills/CBC

Trying to absorb heat on surfaces

This month, orange clouds of Asian lady beetles have clustered in the hundreds on white surfaces and windows in an attempt to absorb the unseasonal heat.

"It's spectacularly bad," said Natalie Rowe at Bee Meadow animal rescue Farm in Apple Hill, Ont., about an hour southeast of Ottawa.

At one point this month a "snowstorm" of  beetles drove the farmer back indoors where she found orange bodies turning up in both the tea kettle and the coffee maker.

"I was reading in bed last night, one was climbing across my glasses, then one was in my teacup," said Rowe, whose vacuum cleaner has been her main weapon of defence during the siege.

At Julie Clement's home in the Kars community of rural southeast Ottawa, she has had to "vacuum hundreds out of the light shades from last year."

"They're a pest," she said.

Stu Mills/CBC
Stu Mills/CBC

No disease or reproduction concerns

On the plus side, the insects don't carry disease and while they might pack into gaps behind walls, they will not reproduce in your home.

On the negative side, they can stink when treated inhospitably. The unwanted guests have a ghastly trick of defensively bleeding their vital hemolymph or blood, which can be mildly poisonous and foul-smelling, and can stain.

"That's how they can get away with crawling around on plants and being bright orange in the middle of the day," said Douglas.

Unlike ladybugs, the Asian lady beetle will also bite.

"They're not terrible, but you can certainly feel it. It feels like a sting," said Rowe.

Lady beetles need temperatures above 10 C to survive, which means they will soon disappear as quickly as they arrived.

Stu Mills/CBC
Stu Mills/CBC