Scary smells: How aphids use odor cues from their natural enemies to determine predation risk

Prey animals rely on several sensory modalities to determine their safety from predators in a given environment. If risk of predation is detected by the prey, a series of physiological or behavioral changes are exhibited within the animal, which can come at a great cost to prey fitness in exchange for survival. These trait changes in prey in response to predation risk are considered the non-consumptive effects. With insects, olfactory cues are commonly used to convey information between organisms, and it’s been shown that insects may also tap into odor cues as a means to determine predation risk. Our research explores the non-consumptive effects of two natural enemies, ladybeetles and parasitic wasps, on the behavior and performance of aphids. Specifically, we interested in the importance of olfactory cues as a mechanism of detection of predation risk for aphids. We ask these questions using the green peach aphid (Myzus persicae (Sulzer)), the multi-colored Asian lady beetle (Harmonia axyridis), aphid parasitic wasps (Aphidius colemani), and collards (Brassica oleracea) as a system. Our research has demonstrated that lady beetle odor cues are detected by aphids via electroanntenography, and aphids exhibit behavioral changes in response to these odors. Behavioral bioassays with aphids and parasitoids suggest the developmental stage of the wasp may play a role in aphid determination of risk. By investigating both the mechanisms of detection of predation risk and the triggered consequences in prey behavior, we are opening up research exploration in the manipulation of risk-induced behaviors for applied purposes.