As long as they're released, catching and observing them can be a good way for both children and adults to study nature and gain an appreciation for the smallest lifeforms. Just be sure it's ladybugs you're handling and not Asian lady beetles. Warning: This article contains a veterinarian's photo of lady beetles lodged in a dog's mouth.
Why the difference matters
You probably know what a ladybug looks like and may have heard about the Asian lady beetle. The first one is a beneficial insect while the other is a smelly pest.
Asian lady beetles (Harmonia axyridis) like those below are not the same insect as the ladybug (Coccinella). It can be difficult to tell the two species apart. Identifying the differences will help you eliminate the bad bugs and protect the beneficial ones.
In quite a few places in the United States, Asian lady beetles have destroyed the native American ladybug by infesting them with mites and outcompeting them for resources.
Although the two look similar and belong to the same insect family, they don’t act the same way. Ladybugs are highly beneficial, harmless, do not bite or congregate in large groups. They feed on destructive garden pests like aphids, mites, scale insects, and whiteflies.
Asian lady beetles hunt garden pests as well, but that's where the similarities stop. They are considered a true pest. Unlike ladybugs, Asian lady beetles will gather in large groups around warm surfaces like windows and invade homes and buildings.
Asian lady beetles bite
Asian lady beetle bite by scraping the skin. They leave a yellow, foul-smelling liquid on surfaces where they congregate. These beetles try to enter homes to find protection over the winter, so telling the two apart is important. Even if you're a fan of ladybugs, you don't want the imposter Asian lady beetle inside your home.
Ladybugs and Asian lady beetles look similar, but there are key differences. Asian lady beetles are slightly larger than ladybugs. All ladybugs are bright red with black spots while the color of Asian lady beetles varies from red to orange. Ladybugs have a round or oval shape. Asian lady beetles are usually a little longer and the head or snout is more pointed.
The easiest way to tell them apart is the head. Ladybugs have mostly black heads with small white markings that sometimes resemble cheeks. These are found only on the sides of their heads. Most Asian lady beetles have a small, dark marking shaped like an M or W on the whitish area behind the head. This marking varies in size and shape but is always present.
While ladybugs overwinter in sheltered outdoor locations, Asian lady beetles enter homes seeking warmth. If you notice bugs congregating in or around your home in fall or winter, they’re probably Asian lady beetles. They can be found around siding, roof shingles, attics, doors, window frames, and dark, undisturbed areas. Asian lady beetles may also enter homes and buildings during spring.
An obvious way to identify Asian lady beetles is by the presence of reflex bleeding. When threatened, these beetles will often excrete a foul-smelling yellow liquid from their leg joints. This may also happen when they're crushed. The excretion isn’t dangerous, but it can stain surfaces and trigger minor allergic reactions. It's particularly noticeable where Asian lady beetles gather on warm surfaces and around access points.
How to keep them out
Asian lady beetles are naturally attracted to bright colors like whites, grays, and yellows. Look for them on sunny, brightly-colored surfaces. When ladybugs enter homes, it’s usually by accident. Asian lady beetles congregate on window frames or wall spaces and wander in through cracks. Once inside, they tend to congregate in dark, secluded places for warmth, including attics, crawl spaces, closets, and storage areas. They particularly like hiding behind framing and siding.
Don’t crush any beetles you find. Vacuum them and dispose of the bag. Use soapy water to clean the surfaces where they congregate. They aren’t dangerous but can be extremely messy.
A problem for your pet
Veterinarians sometimes find lady beetles lodged in a pet's mouth. Insects do get inside dogs' mouths, usually ants and flies the dogs chase and eat, and can be problematic. It's extremely rare to find an Asian lady beetle in a dog's mouth. However, it does occur.
If the beetle becomes embedded in the soft pink tissue that lines the mouth, it will fight back by excreting a toxic chemical substance that burns the dog's mouth. Once the beetle is stuck, it's very difficult for the dog to dislodge it. Manual removal is usually required.
The chemicals produced by the Asian lady beetle can cause ulceration of the gastrointestinal tract when swallowed. In severe cases, they can be fatal.
Do Asian beetles attack dogs? No. Dogs like to bite at insects and may get a few Asian beetles when they do, especially if they snap at a group of them on the ground. This is rare. You can stop the problem by teaching your dog not to eat insects.