What Are Those Tiny Beetles Crawling Up My Walls?

By Chris Williams on May 2, 2012.

You may have seen little, dark beetles crawling up your walls lately. Or, you may have found them dead in window frames or on windowsills. At this time of year, what you’re probably seeing is carpet beetles searching for a way out of your house. The newly emerged adult beetles are attracted to light. Carpet beetles are a common indoor pest but most people don’t notice them, except for this time of year when adults are on the move. They’re tiny and the larvae are often hidden and protected in dark cracks, crevices, and out-of-the-way sites.

There are three different species of carpet beetle that are common in homes. They are all round, very small (about 1/8-inch long, not much bigger than the head of a pin) and if you looked at them up close you would see that they have calico coloration—various splotches of brown, orange, black, white, and yellow, depending on the species.

carpet-beetle2Carpet beetle adults tend to emerge in early spring. And, this year with our warmer-than-normal winter, they seem to be emerging even earlier than usual. They crawl from the wool carpet, or the lint around the baseboard, or the cat hair under the sofa, wherever the larvae have been feeding. The larva is about 1/4-inch long, brown, and hairy. Sometimes you can find a pile of shed larval skins under carpets or other infested items.

It’s the larval stage of the carpet beetle that does the damage—feeding on woolens, hair, feathers, and other animal materials. Strangely enough, the adult carpet beetle feeds on pollen and nectar and is common on outdoor plants. This is why the adult beetles are now climbing walls and heading for windows, looking for a way to get outside to feed and mate. Once mated, the female carpet beetle avoids light and may move indoors to lay eggs in suitable dark areas. Since carpet beetles can fly, finding an entrance through a door, window, or vent is not difficult. The unsuspecting homeowner may even carry them inside on cut flowers from the garden.

While carpet beetle larvae can be feeding on woolens or even a mouse carcass in a wall void, in most homes they are found wherever hair, lint, dead insects, and food crumbs accumulate—under furniture, along baseboards, in corners, places that are often missed by vacuuming. Homes with pets are more at risk of carpet beetle infestation because of the accumulation of overlooked pet hair in hidden areas. Frequent and thorough vacuuming will help to prevent and remove carpet beetle infestations. Time to use that crevice tool!

[For illustrations of the adult and larval stage of the carpet beetle, check our Pest Library and look under Fabric Pests.]

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