The Asian lady beetle (Harmonia axyridis), also known as the multicolored Asian lady beetle, harlequin lady beetle (because of the species' tendency to vary in color from orange to yellow to even black), and Halloween lady beetle (because it invades homes in October in preparation for hibernation), is a well-known non-native insect common in both North America and Europe .

When the species first "hit" the UK, it received the label of "the many-named ladybird". Among the names listed were: Multivariate, Southern, Japanese, and Pumpkin ladybirdLadybird Survey page "Harmonia axyridis (Pallas) in Britain" 1 Accessed 7 Jan 2008.

Note: species in the family Coccinellidae are known as ladybird in the UK; hence, the British name is harlequin ladybird.

Background

This species was possibly established in North America as the result of introductions into the United States in an attempt to control the spread of aphids. Whatever the source, in the last two decades, this insect has spread throughout the United States and Canada and has been a prominent factor in controlling aphid populations. However, many people now view this species as a nuisance, partly due to their tendency to overwinter indoors and the unpleasant odor and stain left by their bodily fluid when frightened or squashed. It is also currently increasing in Europe to the detriment of indigenous species, due to its voracious appetite which enables them to out-compete and even eat other lady beetles, as it also does in the United States.

North America

In the U.S., the first attempts to introduce it took place as far back as 1916. Repeated efforts were not successful. In the early 1980s, aphids were causing significant problems for growers of pecan trees, so the United States Department of Agriculture again attempted to bring the insect into the country—this time in the southeastern United States, using beetles brought from their native region in northeastern Asia. After a period of time, USDA scientists concluded that their attempts had been unsuccessful. However, a population of beetles was observed near New Orleans, Louisiana around 1988, though this may have been an accidental introduction event independent of the original, planned efforts. In the following years it quickly spread to other states, being occasionally observed in the Midwest within 5–7 years, and becoming common in the region by about 2000. The species was also established in the northwest by 1991, and the northeast by 1994, in the former case quite possibly involving additional introductions, rather than reaching there from the southeast. It is reported that it has heavily fed on soybean aphids (which recently appeared in the U.S. after coming from China), supposedly saving farmers vast sums of money in 2001. However, in addition to its household pest status, it has been reported to be a minor agricultural pest (contaminating crops of tender fruits and grapes) in Iowa, Ohio, New York State, and Ontario2. The contamination of grapes by this beetle has been found to alter the taste of wine. Native ladybird species have experienced often dramatic declines in abundance in areas invaded by H. axyridis. Despite the troubles the Asian lady beetle causes, many farmers still view it as a beneficial insectFact: date=August 2008.