Effects of rapid evolution on population cycles and extinction in predator–prey systems

Traditionally ecologists have tended to consider species as the smallest unit for understanding community dynamics. However, recent studies demonstrated that there is substantial amount of intraspecific genetic variation and the resultant microevolution can affect ecological dynamics. Here I introduce recent studies showing how adaptive phenotypic changes affect community dynamics, especially in predator–prey systems. First, I review the effects of rapid evolution on predator–prey cycles. Experimental and theoretical studies have demonstrated that the phase lag between predator and prey densities can be changed from the classic quarter to the half (“antiphase cycles”) or three-quarters (“clockwise cycles”) by prey defense evolution or coevolution, respectively. In addition, prey defense evolution can cause “cryptic cycles” where predator densities fluctuate whereas prey densities stay almost constant. Second, I explain how rapid adaptive evolution can prevent extinction (“evolutionary rescue”). Evolutionary rescue with interspecific interactions can create counterintuitive dynamics and will be important for understanding species coexistence in communities. Finally, I discuss future perspectives of empirical and theoretical studies on eco-evolutionary dynamics in complex communities