Michigan's cold weather is causing ladybugs to shelter in our homes

Photo of Angela Mulka
As Michigan tranisitions from autumn to winter and the temperature drops, you may begin seeing some unwelcome visitors in your home: red and orange-colored beetles with black spots. This beetle, or ladybug, is the multicolored Asian lady beetle, Harmonia axyridis, and it is driving people buggy throughout the state.
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As Michigan transitions from autumn to winter and the temperature drops, you might begin seeing some unwelcome visitors in your home: red and orange-colored beetles with black spots.

This beetle, or ladybug, is the multicolored Asian lady beetle, Harmonia axyridis, and it is driving people buggy throughout the state, according to a statement by Michigan State University Entomologist Howard Russell.

During the fall, the beetle congregates on the sides of buildings, enters homes and lands on folks as they walk through their yards.

And it sometimes bites, however, this bite does not seriously injure humans or spread diseases, Russell said.

The multicolored Asian lady beetle is native to Asia and can live up to three years. It is a nuisance pest because the adults tend to congregate and overwinter inside buildings in large numbers, according to an article by Russell.

A home infested by Asian lady beetles and flies during autumn in Canada.

A home infested by Asian lady beetles and flies during autumn in Canada.

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"Some bug people say the beetle does this because in their homeland of China they inhabit tall cliffs to overwinter and that buildings are the closest thing we have to tall cliffs in Michigan," he wrote. "To make matters worse, they supposedly release a pheromone that attracts more beetles to the same area. If crushed, the beetles will emit a foul odor and leave a stain. The dust produced from an accumulation of dead multicolored Asian lady beetles behind wall voids may trigger allergies or asthma in people."

Their appearance in and around people's homes recently was likely triggered by a cold spell that swept through Michigan last week, Gary Parsons, an insect specialist, and director of the Bug House at Michigan State University told Fox 2 Detroit

"(They) are responding to the cold and seeking sheltered places in and around homes for the winter. That is a normal behavior for this species," Parsons said.

Luckily, the beetles do not breed or reproduce in our homes. They lay eggs on the underside of leaves where aphids are present, according to an article published in "American Entomologist."

The bug is present in much of the United States and southern Canada. It is typical behavior for them to head outside when it gets warmer in the spring, according to the article.

If you don't like the insect in your home, and tried caulking or sealing cracks and crevices, Russell suggests sweeping or vacuuming them up. Be sure to empty the vacuum bags afterward. Commercially available indoor insect light traps can also be effective, he said.