Maintenance and evolution of individual differences in a prey defence trait examined with a dynamic predator-prey model

Abstract

Predator-prey systems often feature periodic population cycles. In an empirical system with a heritable prey defence trait, ecological oscillations were previously shown to cause evolution of prey defence on the timescale of the population cycles. In this paper, we develop an eco-evolutionary mathematical model comprising partial differential equations to investigate the evolutionary dynamics of prey defence during population cycles. We reveal that ecological population cycles induce evolutionary oscillations of the mean prey defence trait. In contrast to existing continuum modelling frameworks, our model allows for the evolution of individual variability. We show that eco-evolutionary oscillations select for increased individual variability close to the transition from stable to oscillatory states. We also reveal that evolution of prey defence requires both high efficiency and low cost of prey defence and highlight that more information on trade-offs between cost and efficiency is required.