THE ROLE OF OLFACTION IN CHEMOSENSORY-BASED PREDATOR RECOGNITION IN THE FATHEAD MINNOW, PIMEPHALES-PROMELAS

Solitary fathead minnows (Pimephales promelas) were rendered anosmic a nd exposed to chemical stimuli from a predatory northern pike (Esox lu cius) to determine the role of olfaction in the minnow's ability to re cognize predators on the basis of chemical stimuli. Anosmic fish did n ot respond to the pike stimuli with a typical fright reaction, while c ontrol fish, with intact olfactory receptors, did. These results demon strate that the olfactory system is necessary for the ability of fathe ad minnows to recognize northern pike as a predator and that the gusta tory and single-celled chemosensory systems are not sufficient for thi s recognition in the absence of olfactory input. Olfactory impairment was behaviorally confirmed by exposing minnows to alarm substance (Sch reckstoff).