Eco-evolutionary dynamics of autotomy

The act of deliberately removing a body part-called autotomy-is a behavior that has appeared frequently across the tree of life. Though there are many possible functions for this behavior, it is often thought of first as a mechanism to escape predation. In a predator-prey interaction, autotomy can therefore confer significant benefits to the prey-particularly, the benefit of not being eaten-but it may also incur significant costs, including the energy expenditure required to regrow the body part and any additional consequences of losing the body part in the first place. In addition, the presence of autotomy may affect how predators choose to approach prey. Here, we put these costs and benefits into a game theory framework and analyze the evolutionary, ecological, and eco-evolutionary dynamics of autotomy, considering both predator and prey strategies. We also apply our model to an empirical example using existing data from porcelain crabs. We find a wide range of effects of autotomy on the ecological and evolutionary dynamics of the predators and prey, including the possibility that the prey become locked into performing autotomy by the predators and the possibility that autotomy can rescue predator-prey coexistence.