So it’s wintertime and you notice a mass of ladybugs in your house. Did you try to disturb them and get bitten? Did they release a foul smelling yellow fluid that stained the walls? Yes? Alas you are housing an undesirable house guest, the Asian ladybug (Harmonia axyridis).
The Asian ladybug belongs to the family Coccinellidae which includes all ladybugs (if you are in the US) or lady birds (if you are in the UK). They are larger than most ladybug species and have a M-shaped marking by their head. The Asian ladybug is also known as Japanese ladybug, Asian lady beetle, Harlequin lady bird, Halloween lady beetle or other common names. Beginning in the early 1900’s the Asian ladybug (a native of eastern Asia) was introduced to the United States by the US Department of Agriculture to control pests such as aphids from feasting on important crops. Intentional introductions also occurred in Europe for the same purposes. They did a great job but (there is always a but when talking about introduced species) the Asian ladybug is spreading throughout the US, Europe, Canada, parts of Africa, and parts of South America at an alarming rate. The invasive beetle is now considered one of the fastest spreading invasive species in the UK. In addition to property damage and discomfort to home owners the Asian ladybug is contributing to the decline of native ladybug species through predation and biological warfare.
What can you do to help stop Harmonia axyridis world domination? This summer when the aphids (or other pests) start munching on your vegetables and you are considering purchasing a container of ladybugs as a non-chemical solution to your pest problem, do your research and make sure you are purchasing native ladybugs. If you are really interested in native ladybugs, join the the Lost Ladybug Project and help scientists track native ladybug populations.