D3070: Double trouble? Evaluating the effects of lady beetle predator odor cues on aphids and their parasitoids

Predator-prey interactions play a crucial role in shaping animal communities, population dynamics, and ecosystem functions. While predators are traditionally considered for their consumptive impact on prey populations, they also induce changes in prey behavior and physiology through non-consumptive effects (NCEs) or predation risk effects. Insects often rely on olfactory cues for communication, and recent research shows that these cues can also signal predation risk. Our study investigates the non-consumptive effects of natural enemies from two feeding guilds, lady beetles and parasitic wasps, on the behavior and performance of green peach aphids (Myzus persicae). We explore the role of olfactory cues in detecting predation risk, using a system that includes multi-colored Asian lady beetles (Harmonia axyridis), aphid’s parasitoid wasps (Aphidius colemani), and collards (Brassica oleracea). Prior research has shown that H. axyridis odor cues cause significant changes in aphid host-plant selection, feeding behavior, and population dynamics. Additionally, parasitic wasps and other lady beetles, being potential victims of intraguild predation, may also respond to predator chemical cues. Our greenhouse experiments assess how lady beetle odor cues influence both predation and parasitism in aphid populations. Combining a total of 6 treatments, we exposed 25 aphids to lethal, predation risk, and combined lethal and predation risk treatments using combinations of parasitoids, lady beetles, and lady beetle odor cues and tracked aphid abundance over time. Understanding these predation risk effects provides valuable insights into arthropod community dynamics and offers potential applications for integrated pest management strategies.