Emma Erler, host of Homegrown NH and lead horticulturist with Kirkwood Gardens, says she often sees ladybugs crawling around her home.
“They’re not dangerous and they don’t hurt the structure or lay eggs, but they are annoying,” she says.
Asian ladybugs were introduced from Asia by the U.S. Department of Agriculture as a biological control. Unlike other introduced pests, Asian ladybugs actually do provide some benefit by preying on soft-bodied insects like aphids, mealybugs, and scales in fields, forests, and gardens, similar to their native counterparts in North America.
Native ladybugs are typically bright red with a few symmetrical black spots and a small, round shape.
Sometimes called ladybirds or ladybeetles, they belong to the class Insecta and are members of the Coccinellidae family of beetles (Coccinellidae means “small red sphere” in Latin).
Native ladybugs are beneficial insects that play a major role in keeping down populations of insects that feed on plants.
Native ladybug species will typically hibernate outside in winter under rocks, in hollow logs or other natural structures.
Asian ladybugs, often called lady beetles, are quite variable in appearance. Their color can range from orange to red. The wing covers are either unmarked or covered with as many as 22 black spots. The most distinctive identification is a black M-shaped marking in the white area behind their heads.
Asian ladybugs are “overwintering” insects that hibernate as adults and spend the winter in protected places such as under tree bark or beneath the siding of buildings. They will sometimes gather in large groups, especially around warm, reflective surfaces like windows and on the south sides of homes.
Some insects make their way indoors in the fall to overwinter, and once the temperature rises over 50 degrees, the warmth inside awakens them from their hibernation. They can be found crawling around windows, walls and ceilings.
They are not dangerous to people, pets, or the structure of the home and do not breed or lay eggs inside of buildings.
You can keep them out in the future by sealing cracks around windows, doors, and siding.
Because it’s still cold out, Asian ladybugs that find their way indoors can’t be saved or put outdoors (unless you have a large supply of aphids or mealybugs on your houseplants!). You can vacuum them up with abandon as the species is invasive and in no danger of disappearing from the landscape.
See you in the garden!
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Homegrown New Hampshire is a collaboration between Squam Lakes Natural Science Center and NHPR.
