Increases in predation favour evolutionary shifts in behavioural plasticity in Trinidadian killifish (Anablepsoides hartii).

This article investigates how increased predation influences the evolution of behavioral plasticity in Trinidadian killifish (Anablepsoides hartii). By comparing populations from high-predation sites with those from predator-free ("killifish-only") sites, the study assessed aggressive and antipredator behaviors before and after exposure to predator chemical cues using mirror assays on both wild-caught and second-generation lab-reared fish. Results indicate that killifish from predator-rich environments exhibit decreased overt aggression in response to predator cues, reflecting evolved behavioral plasticity, whereas fish from predator-free sites show less pronounced or opposite responses, likely due to differing selective pressures such as competition. The findings support the hypothesis that predation risk favors the evolution of predator-mediated behavioral plasticity, with wild fish from predator-free sites retaining some ability to respond to predator cues, suggesting a complex interplay between genetic and environmental influences on behavior.