On a sunny fall afternoon, they cluster by the dozens on the south side of the house. A few days later, they’re on your window frames, your ceiling, even your lampshades. Those “ladybugs” aren’t lost: they’re looking for a place to spend the winter, and your home is on the list.
In short
- Most of the “ladybugs” invading homes in fall are multicolored Asian lady beetles, a species that isn’t native to North America.
- They gather on sunny, south- or southwest-facing walls looking for a place to overwinter.
- Inside, they hide in attics, ceilings and wall voids, and can wander into living areas on warm days.
- The best fix: vacuum them up and seal the cracks they use to get in.
Not the ladybug you think
The insects that show up by the hundreds in fall are usually multicolored Asian lady beetles. According to Penn State Extension, the species is native to East Asia, and the first established populations in the U.S. were found in Louisiana in 1988, likely introduced by accident through shipping cargo. It has since spread widely and is displacing native lady beetles.
Why your house?
In early October, the beetles gather outside buildings on warm, sunny afternoons after cold nights, Penn State Extension explains. They’re drawn to sunlight reflecting off south- or southwest-facing walls. University of Kentucky Extension entomologist Lee Townsend noted that they’re “attracted to its shape or reflected color,” and that homes in or near wooded areas are especially affected, as UK’s College of Agriculture reported.
The spot they choose
Once inside, large numbers collect in attics, ceilings and wall voids. In nature, they would spend the winter under tree bark or in leaf litter. In a house, warmth coming through the walls can make them move through those voids and end up in your living room on mild winter days. Then, as spring approaches, they head back outdoors. Like other animals looking for shelter, they’re following a simple instinct, as we explained with where rats go in winter and the spot snakes choose around your home.
Why you shouldn’t squash them
When disturbed, these beetles release a “stinky, yellow defensive chemical” from their leg joints, according to Penn State Extension. It can stain walls and surfaces, and some people get a small, localized welt from it. They can also occasionally bite. Pets that eat them may suffer chemical burns in the mouth.
How to get rid of them
- Vacuum them, the most efficient method. With a bagless vacuum, put a nylon stocking in the hose and secure it with a rubber band to trap them.
- Empty or freeze the bag after each use if your vacuum has one.
- Skip insecticide in the walls: Penn State warns it can attract carpet beetles that feed on the dead lady beetles.
- Seal the entry points with good-quality silicone or silicone-latex caulk around windows, doors, siding, pipes and chimneys, repair damaged screens, and cover vents with fine mesh.
The limit
Sealing a house completely is almost impossible, and in wooded areas some beetles will get in no matter what. They don’t reproduce indoors over the winter, and they leave in spring. Native ladybugs are welcome in the garden, where they eat aphids: the goal isn’t to wipe them out, just to keep them out of the house.
That’s the trick.
