Abstract: In order to investigate whether Myzus persicae can recognize the visual and olfactory cues from its predators, bioassays were made on the recognition responses of apterous M. persicae to elytra color and volatiles of Propylaea japonica adults in the laboratory by using the prey-predator system of M. persicae. P. japonica. The results of choice response bioassay showed that apterous M. persicae could detect the presence of P. japonica both through visual sense and olfactory sense, suggesting that there is a certain redundancy in the recognition of visual and olfactory cues. The results of dose-response bioassay showed that there was a positive linear relationship between the dose of the ladybird extract and the repellent percentage of the aphids. The critical dose for recognition was within the range of 0.3-0.6 ladybird equivalent, and the repellence of 1.2-1.5 ladybird equivalent was equal to that of 20 live P. japonica adults. We thus conclude that the aphids have the ability to detect the presence of P. japonica and adopt initiative avoidance responses to reduce the predation risk.

Key words: Myzus persicae, Propylaea japonica, prey-predator system, visual cue, olfactory cue, recognition response, repellent effect