Cultural transmission of predator recognition in fishes: intraspecific and interspecific learning

Abstract

Individuals that live in groups may have the opportunity to learn to recognize unfamiliar predators by observing the fright responses of experienced individuals in the group. In intraspecific trials, naive fathead minnows, Pimephales promelas, gave fright responses to chemical stimuli from predatory northern pike, Esox lucius, when paired with pike-experienced conspecifics but not when paired with pike-naive conspecifics. These pike-conditioned minnows retained the fright responses to pike odour when tested alone, indicating that learning had occurred, and transmitted their fright responses to pike-naive minnows in subsequent trials. Brook stickleback, Culaea inconstans, are found in mixed-species aggregations with fathead minnows and are also vulnerable to predation by northern pike. In a series of interspecific tests, pike-naive brook stickleback gave fright responses to chemical stimuli from northern pike when paired with pike-experienced minnows but not when paired with pike-naive minnows. Pike-conditioned stickleback also retained the fright responses when tested alone and subsequently also transmitted the fright responses to pike-naive minnows. Individuals may benefit from observations of the fright responses of conspecifics or heterospecifics by (1) being alerted to the immediate presence of unfamiliar predators and (2) learning to recognize unfamiliar predators as a potential threat.