Prey fishes use chemical cues in their predator's diet to cue the context and timing of antipredator behaviors that reduce the risk of predation. They also use dietary cues to learn to recognize and later detect the presence of a predator. Because dietary chemical information decreases hunting success of predators there should be selection on predators to mask or obliterate these cues through biochemical processes in their digestive tract. In this study, we compared response intensity of predator-na€ ıve fathead minnows to the signature odors of two novel predators that had been fed either a minnow diet or a non-minnow diet. Unprocessed minnow mash and dechlorinated blank water were used as positive and negative controls, respectively. One predator was from a relatively ancestral fish group, the order esociformes, while the other predator was from a relatively derived group, the order perciformes. Na€ ıve minnows were able to detect the presence of minnows in the diet of the ancestral and derived predators with equal efficiency and behavioral responses to minnow dietary cues were significantly different from non-minnow dietary treatments. We found no evidence that fish of relatively derived phylogeny have evolved counter-labeling strategies through enhanced biochemical processes during digestion.

No abstract