Predator diet cues and the assessment of predation risk by juvenile brook charr: do diet cues enhance survival?

摘要

Recent studies have shown that predator diet cues provide important information that prey animals can use to assess predation risk. Predator-naive prey animals may even learn to recognize unknown predators when they detect conspecific cues in the predator's diet. We examined the importance of predator diet cues in the responses of juvenile brook charr (Salvelinus fontinalis) to chemical cues of predators. In our first experiment, we showed that charr respond to chemical cues of adult yellow perch (Perca flavescens) that were fed a diet of either brook charr or rainbow trout (Oncorhynchus mykiss), but not to perch fed a diet of brook stickleback (Culaea inconstans). Responses to diet cues from perch fed both charr and trout may indicate that charr are responding to evolutionarily conserved salmonid alarm cues in the predator's diet. In a second experiment, we exposed charr to chemical cues from predatory northern pike (Esox lucius) that were fed charr, trout, or stickleback. Live-predation trials revealed that charr exposed to diet cues from pike fed salmonids exhibited higher survival than charr exposed to diet cues from pike fed a non-salmonid. These results are the first to document a survival benefit for prey exhibiting behavioural responses to predator diet cues.