Discriminative predation stabilizes the fig-fig wasp mutualism in a patch-dynamic framework

How plants and pollinators maintain their mutualistic interaction stability under the threat of third parties—such as cheating pollinators, parasite species, and high trophic level predators—remains an intriguing open question in ecology. Here, we introduced a patch-dynamic model, to analyze how predator (i.e., ants) regulates the mutualistic stability of the fig-fig wasp community. Our results showed that the predator can suppress the positive effects of fig size on fig wasps (i.e., top-down effects). Moreover, maintaining species diversity and host-pollinator mutualism requires pollinators to maintain significantly higher oviposition efficiency than non-pollinators. Finally, the predator can maintain the site occupancy proportions of mutualists (e.g., figs and pollinators) at high levels when the predation rate of the predator to non-pollinators is higher than the pollinators. Overall, our findings demonstrate that predators may pose a threat to the “cheating” behaviour of non-pollinators through flexible foraging strategies, which improves reproductive success between pollinators and figs as well as contributes to increasing the site occupancy proportion of host seed. Our work highlights predators’ roles from mere population regulators to architects of mutualistic network stability, emphasizing their indispensable function in mutualistic systems.