Massachusetts residents may have mixed feelings about ladybugs, as the seven-spotted ladybug species is the official state insect of Massachusetts, but the insects are also known as nuisance home-invaders in the state. Ladybugs are abundant in the northeast and many people have no qualms about handling these insects with their bare hands on account of their small size and quirky orange shell that features black polka-dots. Surprisingly, many ladybugs are not native to the United States, as many species, including the seven-spotted ladybug, was introduced into the US in order to allow the insects to feed on damaging crop pests, namely aphids. In other words, non-native ladybugs serve as biological agents to control crop damaging aphids. This plan proved to be a success, but unfortunately, another introduced ladybug species, the Asian lady beetle, often invades homes in large number in numerous regions of the US. Massachusetts residents are particularly vulnerable to Asian lady beetle infestations within their homes where the insects can leave behind noxious fluids that smell foul and can stain walls.

The first introduction of Asian lady beetles into US crops occurred back in 1916, but during the 1970s and 1980s larger amounts of the insects were introduced more frequently into the US. It was not until 1988 that researchers documented the first established populations of Asian lady beetles. These first habitats were clustered in Louisiana and the southeast, but experts have argued that these first habitats were founded by lady beetles that had been accidentally introduced into the US by means of international trade. These non-native insects rapidly moved north where they conquered most of the US and southern Canada, although they were also imported into the east coast. The lady beetles became most abundant within forested habitats, which explains their high population in Massachusetts and the rest of New England.

The Asian lady beetle arrived in Massachusetts in the early to mid 1990’s, and it did not take long before pest controllers in the state became overwhelmed with calls about homes being invaded by the pests. Asian lady beetles can appear in Massachusetts homes all year round, as these insects naturally gravitate to homes during the winter where they secretly dwell within walls. Come spring, the lady beetles emerge from the walls in large number. When this occurs the insects secrete a fluid that leaves yellow stains on walls, drapes and carpeting, and when infestations are particularly heavy, this fluid can stink up houses. Unfortunately, experts believe that Asian lady beetle populations in Massachusetts will continue to increase over the next two decades due to the abundance of lady beetle prey in the state. In order to remove Asian lady beetles from a home, experts recommend vacuuming up the insects, as crushing them will cause them to bleed their smelley internal fluids.

Were you aware that Asian lady beetles were imported into the US for the purpose of biological pest control?