They catch us by surprise, these Asian Lady Beetles, when the day is warm and the season late. Every year we wonder, "where do they all come from?"
Apparently they are not as plentiful here as they are in the United States. As the story goes, (Ohio State University Extention Fact Sheet) they were imported, intentionally from the Orient and released in the USA to combat pesky tree insects such as aphids and scale insects. This occurred in 1916, the 1960s, 70s and 80s. Perhaps more of them accidentally came on board ships that harbored in the States.
As the weather gets colder the Asian Lady Beetles migrate looking to hibernate in a cool alternative to the cliffs of the Orient. In North America they prefer buildings. (Native Lady Beetles prefer outdoor sites.) On a warm October day you can see thousands trying to find a way into your home. They then hibernate for the winter where they only occasionally venture forth on a warm sunny day. They neither mate nor eat indoors.
In the spring the beetles move outdoors and the lifecycle continues. Yellow oval eggs are laid which hatch in 3-5 days. The larvae will feed for 14 days on aphids and scale insects. Pupation occurs for 5-6 days after which the adult emerges. The adult can live for 2 - 3 years.
Occasionally they nip, occasionally they are a nuisance.
Yet, take a closer look and admire these tiny creatures the next time you see them.
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