Arrival, Establishment, and Habitat Use of the Multicolored Asian Lady Beetle (Coleoptera: Coccinellidae) in a Michigan Landscape

A monitoring system established within an array of cultivated and uncultivated habitats was used to characterize the first 5 yr of establishment of the exotic multicolored Asian lady beetle, Harmonia axyridis (Pallas), in an agricultural landscape of southwestern Michigan. Population trends over time were summarized for 11 species of resident coccinellids before and after the arrival of H. axyridis . In addition, annual population increase, habitat utilization patterns, and within-season population fluctuation for H. axyridis were analyzed. H. axyridis became a dominant coccinellid species in the landscape 4 yr after its arrival. Adults of this species were found in all 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. Resident species that appear affected by the establishment of H. axyridis are Brachiacantha ursina (F.), Cycloneda munda (Say), and Chilocorus stigma (Say). However, to attribute the decline on the numbers of those species to H. axyridis will require further assessment.