Examining the non-consumptive effects of predators on the pea aphid (Acyrthosiphon pisum)

Aphids are a widespread agricultural pest of many ecologically important crops. Biological control is known to be an effective measure to reduce aphid populations using a variety of predators and parasitoids, Coccinelids being a famously voracious predator of aphid species. Aphids typically respond by employing evasive maneuvers, like dropping down to the understory, to avoid an impending predation or parasitization event. However, it is unclear to what degree the feeding behaviour of aphids is affected outside of consumptive events; that is, whether the presence or evidence of local predators, the non-consumptive effects, impacts the feeding activity of the aphid. To examine this question, electropenetrography (EPG) was used to study the response of the pea aphid (Acyrthosiphon pisum), a widespread pest of agricultural legume crops, to the visual and chemical signals of the aphid predator, the two-spotted ladybird (Adalia bipunctata). Adult A. bipunctata were adhered to leaves of Pisum sativum before exposure to the aphid subject. The ability for predator presence to alter feeding ability of A. pisum has implications for the effectiveness of biocontrol methods beyond consumptive predation events, contributing to the body of research involving the role of biocontrol in agricultural and horticultural contexts..