Prey Cue Preferences Among Northern Cottonmouths (Agkistrodon piscivorus) Acclimated to Different Year-Long Diets: Genetics or Experienced-Based Plasticity?

Abstract

Chemoreception and recognition of specific prey are important sensory modalities for optimizing foraging success in snakes. Field observations suggest that cottonmouths are generalists, despite the specific epithet of the species (piscivorus) suggesting a fish prey preference. Because chemo-recognition of specific prey may reveal interesting evolutionary context for foraging strategy and if prey preference is either genetically or environmentally controlled, we investigated the prey cue preference of three experimental groups of Agkistrodon piscivorus (Northern Cottonmouths) with different diet histories. Two groups of captive snakes were acclimated to year-long diets of either fish (n = 11) or mice (n = 9) and a third group of recently wild-caught individuals served as a field diet group (n = 16). We investigated possible differences among diet history (fish, mouse, and field) and prey cue preference (control, fish, and mouse) and present results showing a significant difference among diet history with field snakes having significantly lower tongue-flick response. We also found a significant difference among prey cues, snakes within all diet histories showed a lower tongue-flick response to only the control scent cue. Both captive and field snakes showed no prey cue preference for either fish or mice. Because captive snakes did not show increased prey cue preference to their respective diet history, prey preference may be under genetic influence and not experience-based. Additionally, the lack of prey preference for fish or mice in the recently captured snakes in the field-diet group provides supporting evidence that A. piscivorus are generalists and opportunistic predators.