Understanding mechanisms underlying predator induced wing polyphenism in the pea aphid (Acyrthosiphon pisum)

Predation is a strong biotic factor that induces morphological, behavioral and physiological changes in the prey. Wingless pea aphids (Acyrthosiphon pisum) produce discretely different winged offspring in response to environmental cues such as crowding and predation risk. When a predator attacks a pea aphid, the aphid releases alarm pheromone and other aphids respond to it by walking away or by dropping off the plant. This increases the aphid movement which in turn increases physical contact between them giving rise to an effect similar to crowding called pseudo crowding. Pseudo crowding has thus been proposed as a proximate mechanism of offspring wing induction in the pea aphid. We hypothesize that there is an alternative mechanism for predator induced wing polyphenism in the pea aphid. Our aim is to investigate if solitary pea aphids also produce winged offspring in response to cues (tracks, feces and eggs) of adult predatory lady beetles, Hippodamia convergens and Coccinella septempunctata. Furthermore, we hypothesize that a higher proportion of pea aphids will get induced and produce a higher proportion of winged offspring when exposed to cues of lady beetle predators as compared to unexposed aphids. Here we will present the results of our experiments investigating influence of predator cues on wing polyphenism in the pea aphid.