Evolutionarily Driven Shifts in Communities with Intraguild Predation

Abstract

Recent studies investigating feedbacks between evolution and ecology suggest that microevolution may affect community structure. Motivated by this, we use a quantitative genetics and Lotka-Volterra framework to understand the impact of eco-evolutionary feedbacks on an intraguild predation community in which the intraguild predator evolves between a phenotype specialized for attacking its competitor (the intraguild prey) and a phenotype specialized for attacking a common resource. We show that evolution can drive both sudden and gradual shifts in community structure. Evolutionary rescue of the community, in which evolution prevents the loss of species, occurs in two ways: (i) selection to a particular phenotype that supports coexistence and (ii) continuous evolution between prey- and resource-specialist phenotypes that support community-level Red Queen dynamics in which the community fluctuates between prey- and predator-dominated states. Paradoxically, the predator can evolve to extirpate itself from the community provided that the ecological dynamics support bistability. Strong trade-offs between specialist phenotypes can lead to trait-based alternative states of the community resembling either a food chain or exploitative competition. Finally, we show that rapid evolution can stabilize equilibria that are unstable for the ecological dynamics, whereas slow evolution can stabilize equilibria that are unstable for the evolutionary dynamics. Our results demonstrate that eco-evolutionary feedbacks can drive shifts in community structure and that the overall dynamics depend on the trade-off strength and evolutionary rate.