Chemically-Mediated Predator Inspection Behavior by Fathead Minnow (Pimephales promelas)

Abstract

ABSTRACT In the absence of visual cues, information gained from chemically-mediated inspection behavior may serve to reduce predation risk by informing minnow shoals of the proximity of potential predators. Behavioral inspection of predator chemical cues implies that sensory modes other than visual detection may be important for assessing predation risk in shoaling fishes. To assess the potential for inspection behavior by fathead minnow (Pimephales promelas; FHM), we quantified the responses of FHM to chemical cues of a natural predator, northern pike, and chemical cues of conspecifics. The presence of northern pike odor elicited inspection-like behavior among FHM. In control treatments, FHM remained within vegetated cover, and no differences were observed in the number of individuals in open water areas. When northern pike odor was added, significantly more FHM were observed in the open water habitat, although FHM activity was similar to that of controls. This suggests that FHM respond to northern pike chemical cues via directional movement into the open water habitats. These results indicate that FHM acquire information about potential predation risk in the absence of visual cues and engage in seemingly high risk investigating activity.