Social learning in predators: Indirect effects let novel prey exclude familiar prey.

Predation is a fundamental ecological process. Social learning by predators is ubiquitous. However, social learning is not incorporated into most ecological theories of predator-prey dynamics. We report how social learning changes results of classic one-predator, two-prey models. In our study, one prey (familiar) can be innately exploited by any predator. The other prey (novel) can only be exploited by predators that have learned how to consume it (i.e., informed predators). Social learning converts naïve predators into informed predators via mass action. This governs exploitation of the novel prey. Indirect effects such as apparent competition then emerge among familiar and novel prey. We find that the novel prey is a superior apparent competitor to the familiar prey because it has a refuge from naïve predators. Faster social learning helps the familiar prey coexist because it erodes this refuge. Other outcomes, such as apparent mutualism and apparent predation, occur when the system exhibits limit cycles. Social learning tends to dampen cycling relative to classic models of apparent competition, but can also exaggerate indirect effects. Our theory is applicable to biological invasions, where it predicts that social learning may determine the persistence of invaders and native species.