Cold weather is driving hordes of Multicolored Asian Lady Beetles inside Mainers' homes, where they are not always welcome guests. Credit: Courtesy of Griffin Dill

This story was originally published in October 2017.

The first few frosts have come and gone this fall and with them has arrived an army of tiny, seasonal insects looking for a place to call home this winter: Lady bugs.

“This time of year we are encountering the multicolored Asian Lady Beetle,” according to Clay Kirby, insect diagnostician with University of Maine Cooperative Extension. “They have this habit of coming into buildings in the fall usually after a cold snap or after a first frost or two [because] that signals to them ‘let’s group up and find a place to spend the winter.’”

Commonly called “lady bugs,” the multicolored Asian Lady Beetle (Harmonia axyridis) is also nicknamed “the Halloween Lady Beetle,” Kirby said.

“It’s the time of the year we start seeing them,” he said.

These beetles are not looking for treats, and nor are they simply sticking around for a few minutes to collect candy.

Currently, residents in central Maine and along the coast are seeing the diminutive insect grouping in ever increasing clusters in the corners of windows, attics or under the eaves in homes.

“You can get a cluster of them on the side of a building or house,” Kirby said. “But if they find a crack or any opening or crevice, they are going to come inside to the warmth.”

Once they have found a suitable warm spot, he said, they simply go dormant and hunker down for the winter.

“They will stay out of sight for most of the winter,” Kirby said. “But when spring comes and it gets warmer or if their little space heats up for some reason, you will start seeing them again at your windows.”

Luckily, the lady beetles are harmless, beyond exuding a foul-smelling discharge if disturbed.

“They are really just more of a nuisance, Kirby said.

If a homeowner does not want hundreds of tiny winter housemates, Kirby said there are some options.

“I tell people to scoop them up as best they can with a dust pan and broom,” he said. “Or vacuum them up after first using a nylon as a filter on the vacuum hose so they don’t get in the vacuum cleaner all the way.”

Kirby advocates releasing the bugs back into the wild as they are one of nature’s premier predators of aphids which destroy plants like roses and fruit trees.

On a positive note, he said, the lady beetles will not reproduce inside the house over winter, though he added the larval stage is rather fascinating.

“The larvae are part black and part orange with spikes,” he said. “They look like little alligators.”

To prevent an infestation, he said the best plan is to carefully inspect your home and seal off any cracks or holes that could allow them to get inside.

Come spring, he said, it may look like the invasion has started all over again, but they are simply waking up after a long winter’s nap.

“All they want to do is get back outside and look for aphids,” Kirby said.

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Julia Bayly

Julia Bayly is a reporter at the Bangor Daily News with a regular bi-weekly column. Julia has been a freelance travel writer/photographer since 2000.