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Multicoloured Asian Lady Beetle

Common Names
The official common name for this lady beetle is the multicoloured Asian lady beetle, but it is also know as the harlequin lady beetle, and less commonly as the Halloween lady beetle.

Scientific Name
Harmonia axyridis (Pallas)

 

Distribution map from Acorn (2007)

Description

  • Elytra (hardened forewings) are yellowish-orange with up to 20 black spots.
  • The pronotum (behind the head but in front of the elytra) is yellow with up to 5 black spots forming an M-shaped mark characteristic of this species.
  • 4.8 to 7.5 mm in length.

Note: This lady beetle is generally easy to identify because of it's large size and many spots. However, some multicoloured Asian lady beetles do not have as many spots or have no spots at all, so it is important to look at the M-shaped mark on the pronotum.

Habitat

This lady beetle is primarily an arboreal species found in orchards, tree stands, conifer woodland and old-field vegetation, but it can also be found in agricultural areas such as forage crops, corn, soybean, and cereal crops.

Invasion History

The multicoloured Asian lady beetle is native through central and eastern Asia. Since 1916 it has been released across North America as a biological control agent for aphids. It was released in Nova Scotia between 1978 and 1982. In 1988 an established population of the multicoloured Asian lady beetle was found in Louisiana, though it is not the result of an intentional release. Since then, this lady beetle has spread rapidly, becoming one of the most common lady beetles in eastern North America.

Potential Impacts

Introduced species can have huge economic and environmental costs, and can dramatically affect distribution, abundance and reproduction of native species. Recently, ecologists and conservation biologists have voiced serious concerns over negative impacts that introduced species are having on Canada’s ecosystems, placing their threat second to habitat destruction.

Since the arrival of the multicoloured Asian lady beetle there has been a noticeable decline in the abundance of some species of native lady beetles in West Virginia, Michigan, and Florida. Presently, there are no studies to document specific effects in the Maritimes.

Additional Websites of Interest

Literature

Acorn, J. 2007. Ladybugs of Alberta, finding and connecting the dots. The University of Alberta Press, Edmonton, Alberta. Gordon, R.D. and N. Vandenberg. 1991. Field guide to recently introduced species of Coccinellidae (Coleoptera) in North America, with revised key to North America genera of Coccinellini. Proceedings of the Entomological Society of Washington 93: 845-864. Majerus, M., V. Strawson, and H. Roy. 2006. The potential impacts of the arrival of the harlequin ladybird, Harmonia axyridis (Pallas) (Coleoptera: Coccinellidae), in Britain. Ecological Entomology 31: 207-215. Majka, C.G. and D.B. McCorquodale. 2006. The Coccinellidae (Coleoptera) of the Maritime Provinces of Canada: new records, biogeographical notes, and conservation concerns. Zootaxa 1154: 49-68. McCorquodale, D.B. 1998. Adventive lady beetles (Coleoptera: Coccinellidae) in eastern Nova Scotia, Canada. Entomological News 109(1): 15-20.