Asian Lady Beetles Scientific Name: Harmonia axyridis
Asian Lady Beetles Identification
You may know the Asian lady beetle as a “ladybug” or “lady beetle.” Our favorite friends as kids, these insects can actually be somewhat of a pest. Also called the “Multicolored Asian lady beetle,” this species has a larger variety of colors and markings than other species. The beetle is either red with black spots, orange with black spots, or black with red spots. The number of spots on the wings varies anywhere from two to more than 16. In the United States, Asian lady beetles are normally mustard or red colored with 16 or more spots. Other varieties of this species may be black to mustard colored with no spots. The Asian lady beetle has a typical “dome” shape with the head and wing coverings (also known as elytra) almost flush with one another. It is a large beetle—usually seven to eight millimeters long.
Asian Lady Beetle Habitat and Food Source
Like its name suggests, the Asian lady beetle is native to Asia but is now found throughout Europe, England, the United States, Canada, and Central and South America.
The Asian lady beetle hibernates during the winter months in any cool, dry, confined space. This may include inside homes if conditions are right. This beetle prefers forested areas or cliff faces as a nesting location during the rest of the year and is attracted to lighter colors for nesting (such as white buildings.) If suitable outdoor nesting sites are not available, the beetles may venture indoors and nest there—inside walls is their preferred location. Any cracks or crevices are subject to allow entry of the Asian lady beetle. The beetle will most likely be seen outdoors in a sunny spot, but they do occasionally enter homes, especially to hibernate.
Asian lady beetles are considered a beneficial part of most gardens as they feed on aphids and other garden-destructing insects. The Lady beetle’s favorite meal are soft-bodied insects that dwell in trees.
Asian Lady Beetle Life Cycle
The entire life cycle of the Asian lady beetle is approximately one month long. After females lay eggs, they hatch within five days. The egg larvae feed for two weeks on large numbers of aphids, scale insects, and other insects. Young beetles pupate for one week, after which they emerge as adults. Lady beetles have been known to live as long as three years in the wild.
Asian Lady Beetles and Humans
Like many insects, the Asian lady beetle has both virtues and vices. These beetles feed on pesky insects like aphids, eliminating them from the garden ecosystem. This reduces the need for pesticides in many residential and agricultural settings.
From the end of autumn to the beginning of spring, the Asian lady beetle becomes a nuisance for homeowners. As they prepare to overwinter they are found clustered around homes, which makes it likely for homeowners to come in contact with swarms of them as they congregate to hibernate. They may land on humans, food, get smashed underfoot, or swarm around human-inhabited dwellings. Additionally, the Lady beetle may seek hibernation sites indoors or on the exteriors of homes. In attics, wall voids, window frames, under shingles, under sidings or landscape timber are all places a homeowner is likely to encounter the Asian lady beetle as she sets up her hibernation spot. These beetles frequently venture indoors looking for warm places. In the spring, homeowners may see clusters of lady beetles trying to get outdoors after their overwintering stage.
The Asian lady beetle has a defense mechanism in which it will release a yellow body fluid that can permanently stain carpet and upholstery and gives off a foul odor. For this reason the bugs should not be smashed, especially indoors.
Although the Asian lady beetle is not at all aggressive toward humans, there have been a few reports of them biting humans. These “bites” will not break the skin or draw blood and are rarely felt. The fluid dispelled by the Asian lady beetle can trigger an allergic reaction in some people, and if this occurs a medical professional should be sought immediately.
Asian lady beetles are beneficial to some garden ecosystems as they prey on aphids and other garden-loving pests, but can become a huge nuisance when seeking hibernation sites during the winter. This pest should be kept from coming indoors, and all methods possible for exclusion should be employed. Seek professional pesticide application where numbers have become too large to be manageable.