Asian lady beetles, sometimes known in the US as Halloween lady beetles or ladybirds, are often confused for ladybugs. The two are closely related, but Asian lady beetles are typically larger than ladybugs, at about a quarter of an inch long. Their color can vary widely from tan to orange to red, though they are predominantly orange. They have several black spots on their wing covers- 19 spots to be exact- although on some beetles, the spots may be indistinct or missing. Asian beetles eat other insects. They were originally introduced to North America as a form of control for aphids, their favorite food.
Though Asian Lady Beetle adult females are prolific egg layers, their reproduction depends on one key ingredient- prey. Without their prey, Asian lady beetles do not have the protein, and therefore energy, they need to produce eggs. Fortunately, the prey needed to reproduce is not found in your home during the winter. However, fall is a completely different story.
Asian Lady Beetles Around Your Home
Asian lady beetles are most active in the fall, especially October. Like boxelder bugs, lady beetles tend to congregate on the sunnier, southwest sides of buildings illuminated by the afternoon sun. Therefore, homes or buildings shaded from afternoon sun are less likely to attract beetles. Homes that do not have southwest-side shade are not so lucky.
Asian lady beetles seek out crevices and protected places to spend the winter, which is why you may find them frequently in your home. They can find their way in through cracks around window and door frames, behind fascia boards and exterior siding, and within soffits, attics, and wall voids. These beetles emit an acrid odor and can stain surfaces with their yellow-orange secretions. Asian lady beetles can bite when agitated, although this bite feels like a pinprick and is seldom serious.
Did You Know?
The easiest way to tell the difference between a lady beetle and a ladybug: the number of legs! Asian lady beetles only have four legs, whereas ladybugs have six.