To share or not to share: prey-sharing behavior in the larvae of two aphid predators and implications for biological pest control

Abstract

Prey sharing in predatory mammals and birds has been shown to reduce fights for food between predators, increase predation efficacy, and safeguard food availability by reciprocal sharing, providing immediate and delayed benefits for the sharers. However, little is known about the incidence of prey sharing in arthropods and the implications for biological control have been mostly overlooked. In this study, the feeding behavior of two aphid predators, Micromus angulatus and Chrysoperla carnea, was investigated to assess the incidence of prey sharing and its possible consequences for biological control of aphids. A video-recording setup was used to investigate the feeding behavior of the predators at various predator/prey ratios. Different numbers of predatory larvae were placed into arenas containing five Myzus persicae subsp. nicotianae. The behavior of the predators was recorded for four hours and the number of prey killed was scored. Our results indicate that prey sharing is a density-dependent behavior, increasing at higher predator/prey ratios. Larvae of M. angulatus performed prey sharing seven times more often than C. carnea and accepted higher numbers of predators sharing a single aphid. Interestingly, a positive correlation between the number of prey-sharing events and the number of aphids killed by the predators was found, suggesting that prey sharing could increase the kill rate of the predators. Additionally, the presence of conspecific larvae enhanced the predation success of M. angulatus. Our findings indicate that prey sharing is an adaptive behavior that could improve the foraging efficacy and kill rate of arthropod predators.