Elevated tongue-flicking rate to cricket surface chemicals by the arthropodivorous rough green snake Opheodrys aestivus

The rough green snake Opheodrys aestivus is a dietary specialist on insects and other arthropods. In a laboratory experiment, I tested chemosensory responses to chemical cues from several taxa palatable to other snakes and two control stimuli presented on cotton swabs. The snakes tongue-flicked at significantly higher rates in response to cues from crickets than from any of the other stimuli, and none of the other potential prey types elicited more tongue-flicks than cologne, the control for response to an odorous substance irrelevant to feeding. These findings are consistent with existing data for a few other species of snakes that are prey specialists, suggesting that correlated evolution may occur between diet specialization and chemosensory responsiveness to cues from the specialized prey. Tests of additional species of prey specialists are needed to establish whether this hypothesis is correct.