Multicolored Asian lady beetles are swarming in large numbers across the Mid-Atlantic because of late fall warmth. Also called ladybird beetles, this type of ladybug smells bad, can bite you and, if you squish it, produces a messy, yellow stain. This is another invasive insect that has found a home in our area.

The Asian lady beetles are not to be confused with the native ladybugs found mostly in the Western United States, although both come from the same taxonomic group, according to Dan Gruner, a professor of entomology at the University of Maryland. The Asian lady beetles, their color varying from red to orange, are larger and identified by the “M” marking where their heads meet their wings. The native ladybugs tend to have a brighter red color.

The beetles tend to swarm on warm, sunny days in late fall. Unseasonably warm weather has visited the Washington region this week, with three straight days of 70-degree temperatures.

Like stink bugs, the lady beetles are aiming to find a location to overwinter at this time of year. Our homes and office buildings become their targets, and the tiny beetles can easily squeeze through gaps in windows and doors.

“Sure this is weather related,” Michael Raupp, emeritus professor of entomology at the University of Maryland, wrote in an email. “They do this every year as they seek overwintering sites.”

Raupp added they may be particularly numerous this year because it “was generally a good year for prey like aphids with all of the rainfall and lush vegetation”

While some homes get swarmed, others nearby are beetle-free. Buildings that get late afternoon sunshine tend to be magnets for lady beetles, particularly on their south-facing walls, which absorb the sun’s warmth.

And after the beetles enter homes, they tend to congregate on ceilings, around windows and in corners. Like stink bugs, they’re slow and easy to catch, but their numbers can be overwhelming when hundreds enter a room.

I encountered my first multicolored Asian lady beetle swarm two weeks ago while golfing in West Virginia. The cloud of lady beetles flying in the air was far thicker than any cloud of mosquitoes or gnats I’ve ever seen. As I golfed, the lady beetles covered my clothes and golf cart. They were easy to brush off, but more would quickly land in their place.

The beetles are not aggressive toward humans, and throughout my golf outing, I was never bitten, but they do have the ability to give a nip or bite. Their bites are described as feeling like a tickle, and they rarely draw blood.

My lady beetle experience while golfing was mainly an annoyance. During one putt, a beetle landed on my face, which caused me to flinch. So at least I had an excuse for missing.

After golfing, when I returned to my hotel room, over 50 lady beetles covered the ceiling and crawled around the windows. It took me a while to clear them out, and that’s when I learned firsthand they can produce a messy, yellow stain if you squish them.

Since I returned to my home in Oakton, Va., I have seen only one, but I know the swarm is nearby.

We polled our readers on Facebook and Twitter, and multicolored Asian lady beetles have been a big problem for many. As of this writing, we have over 1,500 reader comments about lady beetles, including photos and stories about the pests. Unfortunately, many of our readers have been swarmed.

Here’s a small selection of comments:

  • Jonathan Nateghi-Asli in Shenandoah County: “The worst I have ever seen! There are hundreds I have had to clear from my cabin. Exterminator has come and the critters keep coming.”
  • Sherri Sacelow: “A swarm of them managed to make their way into my home in Annapolis. While I was eating my sushi dinner, a dead one fell from the chandelier onto my tuna.”
  • Patience Chirsler Battisti: “Thousands of Asian Beetles covering our screens and in our screened porch. North of Charlottesville.”
  • Deborah E. Watson: “Dunkirk, MD in Calvert County has a bumper crop. Can’t walk outside without having them fly in your face, into your hair, onto your clothes.”
  • Jill Colby: “I had one bite or pinch my arm yesterday in my backyard in Keswick, VA.”
  • Julie Linkins: “Thousands of them in a swarm near Galesville yesterday. The were coming in through every crack and gap. When I got in my car today, dozens had ensconced themselves in the crevices around the doors and many immediately flew into the car.”
  • Richard: “Tuesday, Dickey Ridge Visitor Center Skyline Drive, while trying to take some pics of the fall colors, I made a hasty retreat to my car as the ladybugs were covering me and crawling inside my shirt. The car was covered in ladybugs hitching a ride back down the mountain.”

While reports of the most extreme swarms come from suburban and rural parts of the area, we’ve received many accounts of them inside the District as well.

According to Raupp, as early as 1916, multicolored Asian lady beetles were introduced into the United States from Asia to control garden pests such as aphids. By the mid-1980s, the beetles were firmly entrenched in the Southern United States, and by 1993, they were reported in the Mid-Atlantic states. The lady beetles are now distributed from Florida to Washington State, he wrote in a blog post.

During a lady beetle’s lifetime, the insect can devour thousands of aphids. They are beneficial to gardens and farms but become a pest when they enter homes to find a location to overwinter.

“To prevent these and other invaders from entering your home, repair screens on your windows and vents, caulk your foundation, seal air conditioners, and eliminate points of entry to your home. Not only will this keep invaders out, but it will also help keep warm air in and reduce your heating costs,” Raupp wrote.

The lady beetles can be harmful to pets if consumed in large quantities, but an article on PetMD says dogs typically won’t eat more than a few at a time because they taste and smell bad.

If you find these beetles in your home, you can sweep or vacuum them up, or the BugZooka insect catcher also works well. But it’s best to release them back outside because they help our gardens. And keep in mind, when lady beetles swarm your home, it’s a sign that winter is around the corner. Cold weather will finally stop the swarm.

Jason Samenow contributed to this report.

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