Functional response of the lady beetle Harmonia axyridis (Pallas) (Coleoptera: Coccinellidae) on the aphid Myzus persicae (Sulzer) (Homoptera: Aphididae)

The functional responses of each instar larva and adult of the coccinellid Harmonia axyridis to adults of the green peach aphid Myzus persicae were estimated under laboratory conditions. Linear parameter estimates from a logistic model of the proportion of M. persicae consumed by H. axyridis were negative at all development stages. Although a realistic estimate for the handling time of first instar larvae could not be produced, functional response curves of fitting the data with a random predator equation exhibited a Type II curve in most development stages. Fourth instar larva had the highest attack rate and shortest prey handling tune. The implications of these results are discussed with more effective stages of H. axyridis in the context of biological control.