Noticing an influx of ladybugs emerging from crevices and openings in your home as the autumn cold sets in? These aren’t the beloved seven-spotted ladybugs that Tennessee holds dear.
Instead, the intruders in your home are probably the Asian lady beetle, also known as the harlequin ladybird or “Halloween beetle” due to their annual appearance in autumn. Both the seven-spotted ladybug and the Asian lady beetle are prevalent among the various lady beetle species in North America. They share red, orange, and black color variations and spots on their backs, but they differ slightly. One significant distinction is the Asian lady beetle’s unique marking near its “neck,” resembling a black “M” or butterfly. Additionally, Asian lady beetles are larger and often have more spots.
These insects tend to invade homes as the weather cools in the fall, often gathering in corners, window screens, and emerging from ceiling fixtures. They are drawn to illuminated surfaces with a light-dark contrast, making partially sunlit homes attractive to them. During winter, they go dormant and reawaken in the spring, occasionally emerging from ceiling fixtures or windows on warm days.
While the Asian lady beetle is invasive, they are not necessarily harmful. Just like the native seven-spotted ladybugs, they are beneficial for gardens and orchards as they consume aphids and other pests. However, their efficiency in predation can make it challenging for native lady beetle species to thrive.
Both the seven-spotted ladybug and Asian lady beetle were intentionally introduced in the U.S. by the Department of Agriculture to combat agricultural pests. Over time, they spread across North America, sometimes outcompeting native lady beetle species.