Stable coexistence through dynamic adaptation of a shared resource

We study a system of self-replicating components that interact with a shared resource. The competition between the components would lead to a phase where only one of them dominates, depending on their interaction strengths with the resource. However, we show that a resource that has a dynamic internal structure can tune the effective interaction strengths and thus stabilize the system in a new coexistence phase. As a case study, we analyze an ecological system with exploitative competition between two predators feeding on a single prey. We consider a scenario where the prey diversifies into two phenotypes. If the ratio of the phenotypes is constant, then one of the predators is excluded. But if the relative abundance of the phenotypes adapts dynamically, then both predators can coexist, in some cases even if they could not persist on their own. The prey may benefit from diversification by spreading the detrimental effect of predation between two consumers, rather than being strongly affected by one.