Migration feedback induces emergent ecotypes and abrupt transitions in evolving populations

We explore the connection between migration patterns and emergent behaviors of evolving populations in spatially heterogeneous environments. Despite extensive studies in systems of ecological and medical importance, a unifying framework that clarifies this connection and makes concrete predictions remains much needed. Using a simple evolutionary model on a network of interconnected habitats with distinct fitness landscapes, we demonstrate a fundamental connection between migration feedback, emergent ecotypes, and a form of discontinuous critical transition. We show how migration feedback-via circulating migration patterns-generates spatially nonlocal niches in which emergent ecotypes specialize. Rugged fitness landscapes lead to a complex, yet understandable, phase diagram in which different sets of ecotypes coexist under different migration patterns. Under certain ecological interactions, a discontinuous transition splits into two continuous transitions-this effect suggests a sensitive experimental probe for the nature and magnitude of the underlying interactions.