Ecologically important traits can evolve at the same rate as changes in species' ecological dynamics (e.g. population densities or spatial distributions). This interaction between ecological and evolutionary processes can potentially alter the ecological dynamics of the system. Here I focus on predator-prey systems where both species evolve and ask, 'how do the effects of coevolutionary dynamics differ from the effects of evolutionary dynamics with a single evolving species?' To address this question I analyze a general predator-prey model where the two species are evolving nearly instantaneously. This fast evolution limit not only makes the analysis more tractable (via fast-slow dynamical systems theory), but also yields insights into the effects coevolutionary dynamics have on the ecological dynamics of the system when evolution is not as fast.
Results/Conclusions
My analysis yields biological and mathematical conditions under which the eco-coevolutionary dynamics of the systems can be accurately predicted by the subsystems that have a single evolving species. However, I also find conditions under which the single evolving species subsystems do not accurately predict the eco-coevolutionary dynamics. In these cases, the interaction between the evolutionary dynamics of the two species yield unexpected coevolutionary dynamics, e.g. one species can become trapped at a fitness minimum or the fitness maximum of both species can become evolutionarily unstable. I also identify under what conditions the ecological dynamics of the eco-coevolutionary system are qualitatively different from those of the subsystems with a single species and those of evolutionary fixed systems. This analysis suggests how some of these different cases can be identified from experimental data and what (sometimes unexpected) effects rapid coevolutionary dynamics can have on ecological dynamics.