Pollinator predation stabilizes plant-pollinator mutualisms through the modification of pollinator behavior

Mutualisms are a basic component of multispecies communities and play crucial roles in the functioning of ecosystems. Early theory on mutualisms, however, predicted that mutualistic interactions could be destabilizing because the interdependent augmentation of mutualists caused their population explosion. Later studies suggested that additional factors, such as costs or saturating benefits of mutualisms and antagonistic interactions that exploited mutualisms, could dampen the destabilizing effect of mutualisms. In plant-pollinator mutualisms, predation on pollinators is a common form of antagonistic interactions, although its effects on the stability of plant-pollinator mutualisms have remained poorly understood. Here, using a mathematical model, we consider whether predation on pollinators can stabilize plant-pollinator mutualisms. We show that predation on pollinators does not stabilize an inherently unstable plant-pollinator mutualism, but the modification of pollinator behavior to avoid predation can stabilize the mutualism. Our results contribute to a better understanding of how predator-induced behavior modification in pollinators can affect the maintenance of plant-pollinator mutualisms.