Weitz Group @ Georgia Tech Theoretical Ecology and Quantitative Biology

Coevolution can reverse predator-prey cycles (new paper in PNAS)

Posted by jsweitz

Populations of predators and their prey usually follow predictable cycles. When the number of prey increases, perhaps as their food supply becomes more abundant, predator populations also grow.

New research shows that the co-evolution of species can affect predator-prey relationships in substantial ways, potentially reversing traditional population cycles. When the predator population becomes too large, however, the prey population often plummets, leaving too little food for the predators, whose population also then crashes. This canonical view of predator-prey relationships was first identified by mathematical biologists Alfred Lotka and Vito Volterra in the 1920s and 1930s.

But all bets are off if both the predator and prey species are evolving in even small ways. When both species are evolving, the traditional cycle may reverse, allowing predator populations to peak before those of the prey. In fact, it may appear as if the prey are eating the predators. A combined theoretical and data-driven investigation of this phenomena led by Michael Cortez a postdoctoral fellow in the Weitz group, was published on May 5th in PNAS.