Our cold, wet weekend was followed by several very lovely, warm, sunny days, with the temperature reaching an unseasonable, but very welcome, 20 degrees (68F). The warmth roused an army of ladybugs. By mid-afternoon, the south side of the house was polka-dotted with the little beetles. They were also swarming on the ceiling of the greenhouse-stable, with dozens of ladybugs milling and flitting about. These ladybugs aren’t native, but rather Asian Ladybugs (Harmonia axyridis). Asian ladybugs were introduced to North America to control aphids on commercial crops and are now considered an invasive species, threatening the 450 to 500 species of ladybugs native to the continent. Large numbers of Asian lady beetles infesting homes as they seek overwintering sites were first reported in the early 1990s.
Asian Ladybugs are variable in color and are sometimes known as the Multicolored Asian Lady Beetle. These couple of photographs illustrate some of the different colour morphs. Asian ladybugs can be differentiated from native species by their rounder shape (native species tend to be more oval) and white markings that typically define an “M”- or “W”-shaped black area behind the head.
The little children’s rhyme, “Ladybug, ladybug, fly away home” isn’t as cute when it’s your home they are flying to! However, althought they are capable of biting when provoked, they are mostly just a nuisance.