The multicolored Asian lady beetle, Harmonia axyridis, has become established in many areas of the Midwest within the last decade. As it moves into new areas, it has the potential to displace lady beetle species already in the area.
Multicolored Asian lady beetle and 11 other resident species were monitored within an array of cultivated and uncultivated habitats during the first 5 years of its establishment in an agricultural landscape of southwestern Michigan. H. axyridis had become a dominant species in the landscape four years after its arrival. Even though it is predominantly an arboreal species, adult beetles were found in all of the habitats monitored, including early secondary succession, poplar plantation, alfalfa, soybean, corn, and winter wheat. Significant population peaks were observed early and late in the season, depending on the habitat.
Currently, the impact of H. axyridis in agricultural habitats does not seem to be of major concern, since most resident species occupy only part of the habitats that H. axyridis can potentially use. However, a decline in the resident arboreal species Brachiacantha ursina, Cycloneda munda, and Chilocorus stigma is of concern. Declines of different species, probably due to competition with another introduced species, the 7-spotted lady beetle, indicates the need to continue to investigate the potential impact of introduced exotic beneficial insects in North America.
Colunga-Garcia, M. and S. H. Gage. 1998. Arrival, establishment, and habitat use of the multicolored Asian lady beetle (Coleoptera : Coccinellidae) in a Michigan landscape. Environ. Entomol. 27(6):1574-1580
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