Evaluation of Antipredator Responses and Evolutionary Na?vet? for Three Western Fish Species

Authors: Cody Anderson, Brian Wisenden, Craig Stockwell

Year: 2021

Abstract

Many desert fishes that evolved in isolated aquatic communities with limited predation have been dramatically impacted by non-native predators. These observations are consistent with the evolutionary predator na?vet? hypothesis. To explore this possibility, we evaluated antipredator behavioral responses of Shoshone pupfish, Cyprinodon nevadensis shoshone, Amargosa River pupfish, C. n. amargosae, and Red River pupfish, C. rubrofluviatilis. These pupfishes represent a species that evolved without natural predators (Shoshone pupfish), a species in a simple community of itself and one other small fish species (Amargosa River pupfish), and a species from a complex community with many other fish, including native predators (Red River pupfish). Antipredator behavior was evaluated by behavioral responses to conspecific alarm cues (chemicals released when epidermal tissue is damaged by a predator) in terms of change in vertical position in the water column and activity level before versus after delivery of alarm cue compared to behavioral response to water. Contrary to predictions of the predator na?vet? hypothesis, all three species significantly reduced vertical position in response to conspecific alarm cue and showed no response to water (control). These findings are not consistent with the predator na?vet? hypothesis, but are consistent with observations that various pupfish species can co-persist with non-native predators.