Homestead
BDN’s Homestead section is a celebration of rural life. Our writers cover small farms, animals, DIY solutions and fascinating Maine people who find unique ways to live simply. Read more Homestead stories here.
Overnight, ladybugs seem to have appeared in swarms around Maine houses, covering the windows and trying to get inside.
But they’re likely invasive multicolored Asian lady beetles, a different species from storybook ladybugs. They look similar from a distance, but the Asian beetles also come in shades of orange, and a dark “M” shape on their heads sets them apart.
Three other similar species live in Maine, and all try to head indoors for the winter after the first frosts of the season. Although it can be frustrating to deal with the sudden hordes, they won’t cause serious problems in your house and will benefit your garden come springtime.
People often release lady beetles on purpose to eat aphids and other plant pests; that may be how Asian lady beetle populations got established here in the 1990s.
The beetles typically appear around homes when the weather first turns cold in the fall, which sends them the signal that it’s time to find a place to spend the winter. In the wild, they look for cracks and crevices where they can go dormant until springtime; the cracks and crevices of buildings seem like similar spaces to them.
If the bugs actually make it inside your home, where it’s too warm for them to go dormant, they’ll likely starve to death. You could see them again in the spring if they overwintered in unheated spaces on the outside of your house.
They won’t damage your house or lay eggs inside, though when they’re startled their leg joints let out a bad-smelling yellow blood as a defense mechanism that may stain your walls or furniture. Try to avoid squashing them to keep this from happening.
Asian lady beetles are also capable of biting humans, though it’s rare; they can’t break the skin and won’t give you any diseases.
If they’re becoming a bother in your house, vacuum them up. Putting a nylon stocking on the vacuum hose will keep the bugs from clogging it, and they can be easily bagged up afterward. You can also sweep them up into a dustpan.
To keep them from getting inside to begin with, look for any cracks in your house around the foundation, windows, doors, walls and especially the attic that you can seal — a good idea to do this time of year anyway to save on heating costs.
If you try insecticide, use it just in small areas where you know they’re gathering, since they might not come across the insecticide you place in your yard.
Because the beetles are good at controlling agricultural pests like aphids, you might want to release them outside away from your house instead of killing them.
Those small green aphids don’t always seriously damage crops and flowers, but in high enough numbers, they can kill plants and carry disease between them. The Asian lady beetles can eat up to 1,200 of them in their larval stage and up to 270 per day as an adult, according to USDA estimates.
Those particularly concerned with lady beetle welfare can also use a paint brush to sweep them carefully into a matchbox or shoebox with air holes in it to place outside until winter’s end.
