Asian Lady Beetles: Friendly or Fake Ladybug?

Ladybugs. Asian lady beetles. Ladybirds. What's the difference? Are some better than others? And which ones are getting into my house in fall, creating an infestation in spring? Asian lady beetles have a bad reputation, but it's not entirely deserved. These little beetles can be beneficial, and typically not more than a nuisance even in the worst case scenario.

What are Asian Lady Beetles?

Despite common myth, Asian lady beetles aren't "fake ladybugs," but a type of lady beetle, or ladybug. "Ladybird" is just another common name for these beetles. Ladybugs aren't true bugs, which is why scientific circles and insect enthusiasts prefer the term "lady beetle." 

True to their other nickname, the harlequin lady beetle, Asian lady beetles come in a variety of colors including bright red, orange, yellow, and even black. These tiny beetles can have anywhere from no spots up to 19. The easiest way to distinguish an Asian lady beetle from other ladybugs is the distinctive black "M"-shaped mark that most Asian lady beetle species have on their pronotum, or the area between their wings and head. This mark can be solid or broken. Like their name suggests, Asian lady beetles originate from Asia and were introduced to North America to help bolster native ladybug species and deal with pests such as aphids, mites, and thrips. 

Don't confuse this lady beetle with other species! The most common lady beetle native to North America is the convergent ladybug. Typically red, red-brown, or bright orange, this ladybug has a white outline around its black pronotum and two white diagonal lines that look like they're about to meet in the middle, hence this species' name "convergent." Another common non-native species is the seven-spotted ladybug. This red or sometimes orange lady beetle comes from Europe and is identifiable by its seven spots and white markings at the top of its wings. 

Lady Beetles: Good for the Garden

Most lady beetles are great for your garden! These tiny but helpful carnivores eat bugs that can destroy your prized plants. In particular, lady beetles love to munch on aphids, but they'll also hunt down thrips, scale insects, mites, and other small, soft-bodied insects. If you see a lady beetle in your garden, leave it alone. It's doing its job controlling pests you don't want eating your plants. 

While you can find lady beetles for sale to help with pest control, we would recommend against it because they will leave their release location and may cause other issues. Once they're out of the bag, lady beetles will go wherever they can find food and shelter. Also, some claim that artificially boosting lady beetle populations, especially non-native species, is not a good idea. A better option is to attract lady beetles by planting flowers and shrubs they like. In addition to aphids, lady beetles like to snack on pollen, and they're partial to pollen from flowers like alyssum, calendula, marigolds, and yarrow. Keep in mind that their main food source is aphids, so if you have plants that attract aphids, lady beetles may not be far behind.

Asian Lady Beetles vs. Ladybugs

You may have heard that Asian lady beetles bite and other species don't. Well, this one is false. Any lady beetle may bite if it's hungry or feels threatened. Lady beetles generally aren't harmful to humans or most pets, and their bites typically aren't harmful unless you have an allergy. You'll just feel a little pinch. If you have concerns or begin to show signs of allergic reaction, contact your doctor or local poison center.

Despite being intentionally introduced, Asian lady beetles are considered invasive by some. As this lady beetle species continues to thrive, many ladybugs native to North America are in decline. The two-spotted ladybug and the nine-spotted ladybug, both recognizable by the number of spots in their name, were once common in the U.S. but are now considered rare. While researchers haven't found a conclusive link between Asian lady beetles and declining native ladybugs populations, some have speculated that Asian lady beetles may be ousting native species due to their more aggressive eating habits.

Asian lady beetles and native ladybugs are solitary for most of the year, but they will congregate in large groups during winter. While native ladybugs typically stay outside to overwinter, Asian lady beetles prefer cracks and crevices in buildings and structures. This is what leads to dozens—or even hundreds—of Asian lady beetles hiding out in your walls or your ceiling. If you have a lady beetle infestation, it's almost guaranteed that it's actually Asian lady beetles.

Asian Lady Beetle Infestations

Asian lady beetles like to spend winter inside your home, where they can cause an infestation. The cold weather sends all lady beetles looking for somewhere warm to hide out. Native ladybug species, however, will typically find shelter outside under rocks, in plants or hollow logs, or in other natural structures. Asian lady beetles find the cracks and crevices around your home a convenient spot, and the warmth coming from inside inviting. 

Asian lady beetles come indoors in the fall after it gets cold. If there's a warm day during the winter, you might see Asian lady beetles crawling around your windows enjoying the light and warmth, but they'll go back into hiding when it gets cold and dark again. Unfortunately, the warm temperatures indoors can actually do more harm than good to Asian lady beetles, depleting their food reserves before spring. After the fall invasion, you may find a mess of Asian lady beetles in your house. 

While not as overwhelming as a fall invasion, you may notice lady beetles in your home in spring. Warmer temperatures tell all lady beetles it's time to come out of their protected spots and look for food. Surviving Asian lady beetles in and around your home return to the garden and get back to eating aphids, but some may accidentally get stuck indoors. Confused lady beetles that overwintered outdoors may also find their way inside thinking they've found their next meal. 

Live Asian lady beetles also don't like to be bothered. When squashed or threatened, lady beetles emit a foul odor and secrete a yellow fluid that can stain your walls, couch, pillows, and blankets. While this defense mechanism is helpful against predators like birds, it's just annoying for people. Asian lady beetles—along with most lady beetles—typically aren't toxic or poisonous to humans or pets, though some people may be allergic. 

What to Do If You Have an Asian Lady Beetle Infestation

The best way to take care of Asian lady beetles in your home is to prevent them from coming in. Before the first cold snap of fall, take these steps to prevent Asian lady beetle invaders: 

• Check around doors, windows, and other potential entry points and make sure they are sealed tight. 
• Use screens on your windows and doors, or check your existing screens for holes and other damage.
• Keep wood or leaf piles and other natural hiding places away from your house.
• Use Ortho® Home Defense® Insect Killer for Indoor & Perimeter2 to create a barrier around your home that deters insects.

If you do discover an infestation, your best option is to get out the vacuum or a broom. Chemical pest control products aren't much good against an invasion of Asian lady beetles, and remember that Asian lady beetles will secrete a smelly fluid when they're squashed. Instead, use a vacuum, preferably with a nozzle attachment, to sweep up Asian lady beetles. Most Asian lady beetles will survive the vacuum, so release them outside away from your house. 

Asian Lady Beetles: Good or Bad?

As long as they're in your garden, Asian Lady Beetles—and most other ladybugs—are aphid-eating helpers. In your home, they're a minor nuisance. Prepare for a potential infestation in late summer or early fall by checking your home exterior and sealing potential entry points. Asian lady beetles are a bug you can live with and even appreciate—just not inside or in mass numbers.