Acquired predator recognition via epidermal alarm cues but not dietary alarm cues by isolated pupfish

We tested whether Shoshone pupfish Cyprinodon nevadensis shoshone and Amargosa River pupfish C. n. amargosae respond behaviourally to conspecific chemical alarm cues released when epidermal tissue is damaged by a predator. We found that both subspecies reduced activity and vertical position in the water column in response to alarm cues. We then tested if pupfish can use alarm cue to acquire recognition of a novel predator. We trained pupfish with (1) water + odour of largemouth bass fed a diet of earthworms, (2) alarm cues from skin extract (epidermal alarm cues) + odour of bass fed a diet of earthworms, or (3) water + odour of bass fed a diet of pupfish (dietary alarm cues). Pupfish responded to epidermal alarm cues but not to dietary alarm cues. Pupfish were retested with the odour of bass that were fed an earthworm diet. Pupfish that had previously received epidermal alarm cues reduced vertical position and activity relative to the other two treatments. This is the first demonstration of acquired recognition of a novel predator by a pupfish, the first report of partial predator naivete, and opens the possibility of predator-recognition training as a tool for management and conservation of endangered desert fishes.

Automated summary

This study found that both Shoshone pupfish and Amargosa River pupfish respond to conspecific chemical alarm cues by reducing activity and changing their vertical position in the water column. The experiments also demonstrated that pupfish can recognize a novel predator through exposure to epidermal alarm cues, which is the first report of acquired predator recognition in pupfish. These findings have potential implications for the management and conservation of endangered desert fishes.