The name “ladybug” was coined by European farmers who prayed to the Virgin Mary when pests began eating their crops. After ladybugs came and wiped out the invading insects, the farmers named them “beetle of Our Lady.” This eventually was shortened to “lady beetle” and “ladybug.”
The multi-color Asian ladybug, Harmonia axyridis, are the visitors we see seeking shelter in peoples houses in September. Their color varies from a pale yellow to a bright red-orange, with varying degrees of spot brilliance and spot size. A fully-spotted beetle will have 10 black spots.
Introduced as a biological control agent in various states beginning in 1916, they didn’t seem to have become established. Then, in 1988, specimens were found in Louisiana…probably from Asian cargo shipping to New Orleans. Since the early 1990s, this exotic lady beetle has proliferated and moved rapidly from the Deep South into the northeastern states and eastern Canada. It is now widely distributed across much of the United States east of the Mississippi River and is also found on the West Coast (California, Oregon, and Washington).
It has become a nuisance to some homeowners because of its habit of invading houses and buildings in large numbers in the fall, appearing again on warm, sunny days in February and March. They do not breed, lay eggs, or feed inside the home, and are not structurally-damaging. If agitated or squashed, however, the beetles may exhibit a defensive reaction known as “reflex bleeding,” in which a yellow fluid with an unpleasant odor is released from leg joints. This reaction generally prevents predators, such a birds, from eating lady beetles. But in the home, the fluid may stain walls and fabrics.
Despite its annoyance value, H. axyridis preys upon many farmers’ and gardeners’ pests, so is considered beneficial. Some of us simply let them be if autumn entry is made into our homes. Others brush them into a shoebox, store it away, and release them in the spring, when they’ll mate. The 10-15, yellowish, tiny eggs, laid under leaves, generally hatch in 3 to 5 days. Looking like tiny alligators, the larvae are hungry…voraciously feeding for about 2 weeks on aphids, scale insects, and other soft-bodied invertebrates. The chrysalis/pupal stage looks like a tiny shrimp attached to a leaf, and lasts about 5 to 6 days. After emergence, adults can live as long as 2 to 3 years under optimal conditions.