People Think Their Homes Are Being Invaded by Ladybugs, But a Much More Destructive Culprit Is Really to Blame
A ladybug lookalike is invading homes in Maine and eastern Ontario, Canada, as perfect conditions have caused the destructive insect to thrive.
“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, according to CBC.
The beetle dines on aphids throughout the summer but has managed to survive the winter thus far by finding shelter in people’s homes.
The insect is almost indistinguishable from the ladybug, but Douglas said the Asian lady beetle, known to the scientific community as Harmonia axyridis, can be identified by a black “M” or “W” located on its pronotum — the area just behind its head.
While the beetles may look similar, Charles Armstrong — an insect diagnostician of the University of Maine Cooperative Extension — noted a few important behavioral distinctions between the two close relatives, according to the Bangor Daily News.
Ladybugs don’t gather in large groups and don’t enjoy the indoor environment of human homes.
Asian lady beetles, by comparison, love to gather in home windows in large numbers.
What’s worse, while they don’t bite or sting, lady beetles excrete a foul-smelling yellow fluid that stains fabric and walls, a nightmare for homeowners having to deal with throngs of the pesky beetles.
“The liquid is basically part of their blood, and they can ooze it out from between the joints of their legs as a defense mechanism,” Armstrong said. “It’s kind of disturbing when you think about it.”
Disturbing is putting it lightly.
As with many invasive foreign species, the Asian lady beetle was introduced with the best of intentions.
With gardeners plagued by aphid infestations, many were seeking to find a new predator that would help control their populations — and they certainly found a capable hunter in Harmonia axyridis.
However, Maine experienced a long bout of dry weather, on which aphids and mites thrive, and these large numbers of their main food source led to a booming population of lady beetles.
The beetles seeking the warmth of human homes to avoid going dormant during winter are actually choosing to slowly starve due to lack of food, according to Armstrong.
“If they stayed outside in a more natural setting that gets colder and stays colder, they would stay dormant the whole winter,” he said. “So in a way they are killing themselves by staying warm.”
What should homeowners do about the beetles?
When it gets colder, Armstrong said, they’ll stop moving into homes altogether, but in the meantime, he suggests vacuuming the pests up and relocating them back outside somewhere out of the way.
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