Individual survival is dictated by group personality in a marsh ecosystem predator–prey interaction

Abstract Predator–prey interactions structure ecological communities, and personality can significantly mediate these interactions. Personality expression is often contingent on social context, suggesting that group personality may be key in determining the outcomes of predator encounters. Here, we test the influence of individual personality and group composition on survival of the marsh periwinkle, Littoraria irrorata, when exposed to its main predator, the blue crab, Callinectes sapidus, both integral players in mediating the productivity and health of salt marsh ecosystems. Snails were categorized as having bold or shy personality types, which were unrelated to shell length, though neither trait influenced survival when individual snails were exposed to a predator. However, when snails were partitioned into groups differing in personality composition, snails in groups with bold individuals had higher survival than those in groups with none. While group type did not influence the survival of bold snails, shy snails performed better in mixed groups: the presence of a few bold individuals emerged as especially effective in decreasing mortality of shy snails. The effect of personality on predator escape is thus conditional on group personality composition, indicating that social context can directly impact the survival and success of its individual members, with broad implications for community dynamics.