Response of all assemblage of Coccinellidae (Coleoptera) to a diverse agricultural landscape

Changes in species assemblages of predatory coccinellids in response to landscape structure (habitat diversity and patchiness) was studied in a southern Michigan landscape during 1989-1990. Three sites with different mosaics of cultivated (alfalfa, corn, wheat) and uncultivated (deciduous, field succession) habitats were sampled for coccinellid species using yellow sticky traps. The landscape at each site was characterized using the Berger-Parker index for habitat diversity and a relative patchiness index for habitat fragmentation. Relative abundance, species richness, species dominance, and the Kendall coefficient were used to analyze and compare species assemblages among sites. Principal component analysis (PCA) was used to extract factor components per species and site scores, which were compared with landscape indices using the Pearson correlation coefficient. Thirteen species of coccinellids were captured during the 2 yr of weekly sampling. Of these species, Coccinella septempunctata (L.) was the dominant species in the landscape and was equally abundant in the 3 sites. Coleomegilla maculata lengi Timberlake was more abundant in the site that had a corn habitat, whereas Cycloneda munda (Say), Chilocorus stigma (Say), and Brachiacantha ursina (F.) were more abundant in the site that had a deciduous habitat. Overall, the site with a deciduous habitat had higher species richness. There were significant differences in species composition between the site with a deciduous habitat and the other 2 sites. Differences observed among sites were significantly correlated with the presence of uncultivated habitats in the landscape.