Effects of the microsporidian pathogen, Nosema adaliae on the seven-spotted lady beetle, Coccinella septempunctata L. (Coleoptera: Coccinellidae)

Abstract

Lady beetles play an important role in the regulation of aphids and other soft-bodied insects in nature. A noticeable decline in lady beetle populations in North America in recent years has become a significant cause for concern in agriculture systems. The objective of this study was to gain knowledge about the effects of the microsporidium Nosema adaliae from the two-spotted lady beetle Adalia bipunctata L. on larval development and mortality, sex ratio, and adult longevity and fecundity of the seven-spotted lady beetle, Coccinella septempunctata L. Vertical transmission of the pathogen also was examined. Spores were detected in the majority of smear preparations of individuals that were fed microsporidia-infected eggs. Larval development (days) between the control and treatment groups did not differ significantly. Although larval mortality was high for control and treatment larvae, mortality for control and treatment larvae did not differ significantly. Sex ratios differed significantly between the control and treatment groups; however, differences in fecundity and adult longevity were not observed.