Social information use in herbivore prey can influence the success of biological control

Abstract

Predation-risk effects (PEs), i.e. costly consequences of antipredator trait responses in prey, have been the focus of many theoretical and applied studies on predator–prey systems, but we still have limited knowledge on how prey functional traits – such as the ability to acquire and use inadvertent social information (ISI) – influence the susceptibility to strong PEs. In this study, I used an individual-based model to explore how ISI use alters the relative importance of consumptive and predation-risk effects on herbivore prey abundance and total consumption, a proxy for plant damage. I found that ISI use contributed to higher prey abundance by lowering predation-related mortality, but it also decreased prey total consumption through PE irrespective of the relation between prey and predator detection ranges and the type of prey social organisation. Moreover, due to its stronger effect on the non-consumptive component of the total predation effect, ISI use contributed to an overall reduction in prey feeding performance. The estimated strengths of different predator effect components were also comparable to previous experimental findings. These findings provide strong support for the idea that the access to and use of risk-related social information not only result in more prey individuals exhibiting the antipredator response but also leads to strong behavioural PEs with substantial consequences on prey consumption.