Responses of golden shiner minnows to chemical cues from snake predators

摘要

Studies of a limited number of species of fish in the superorder Ostariophysi have shown they they exhibit strong antipredator behaviour to conserved alarm substance in feces and in other byproducts from predatory fish that have consumed ostariophysans. Our experiments examined the ability of a previously untested ostariophysan to recognize chemical cues from two species of snake predators. In Experiment 1, shoals of golden shiners (Notemigonus chrysoleucas) exhibited strong shelter-seeking responses to water which contained waste byproducts from either a sympatric snake or an allopatric snake which had been fed golden shiners but not to a distilled water control. There was no difference in response to the sympatric snake predator, northern water snakes (Nerodia sipedon), compared to the allopatric snake predator, black-bellied garter snakes (Thamnophis melanogaster). In Experiment 2, individual shiners exhibited vigourous dashing when presented with water which contained waste byproducts from N. sipedon fed golden shiners but exhibited a much weaker response to water which contained waste byproducts from N. sipedon fed green swordtails (Xiphophorus helleri, a non-ostariophysan) or to a water control. These results suggest that the alarm substance produced in the epidermis of the golden shiners is conserved in snake waste byproducts. Experiment 3 showed that there was little difference in shelter-seeking behaviour by shoals of shiners when presented with water in which N. sipedon had soaked, water in which T. melanogaster had soaked, or a distilled water control. Thus it appears that secretions from the skin of these predators may not be chemically labelled.