Personality-dependent survival of the invasive mosquitofish: being social can be deadly

Mosquitofish (Gambusia affinis) are a widespread, invasive species that frequently colonize habitats where they might encounter novel predators. Earlier work showed that asocial mosquitofish disperse more readily than social fish. Initial colonists to newly invaded, low density sites should thus be relatively asocial. Here, we tested the hypothesis that asocial mosquitofish should survive better than social fish when exposed to predators at low mosquitofish density. We used standardized behavioural assays to quantify the individual behavioral type (boldness, sociability, activity, exploratory tendency) of 224 mosquitofish, and then exposed them to predators in small groups. As predicted, asocial individuals survived exposure to predators better than social individuals. In addition, while body mass per se did not affect survival, males survived predators better than females. Overall, this study provides an early corroboration of the general prediction that behavioural types that disperse more readily might also be better at coping with predators at low density.