THE ROLE OF NASAL CHEMICAL SENSES IN GARTER SNAKE RESPONSE TO AIRBORNE ODOR CUES FROM PREY

Garter snakes increase tongue-flick rates in the presence of airborne odorants (amyl acetate, limonene, earthworm wash vapor, fish water vap or, earthworms, goldfish) but not water vapor. Main olfactory (MO) ner ve lesions result in loss of this tongue-flick rate elevation in the p resence of airborne odorants. Vomeronasal (VN) nerve lesions result in a diminution of tongue-flick rate elevation. Garter snakes discrimina te between the 2 arms of a maze containing airborne earthworm odor as compared with a blank control. Following MO nerve lesions, snakes fail to make this discrimination. Following VN nerve lesions or VN duct su ture, snakes are initially able to make the discrimination but may eve ntually cease to prefer the prey-odor side of the maze and may stop ea ting prey rewards. These results support the idea that airborne odoran ts are detected by the main MO system and that such detection does not require a functional VN system.