Food chemical cues elicit general and population-specific effects on lingual and biting behaviors in the lacertid lizard Podarcis lilfordi

Actively foraging lizards are capable of identifying prey using only chemic al cues sampled by tongue-flicking, and the relatively few omnivorous and h erbivorous lizards tested similarly can identify both animal and plant food s from chemical cues. Whether lizards that eat plants respond to cues speci fic to preferred plant types and whether there is geographic variability in responses to cues from various plants correlated with the importance of th ose plants in local diets is unknown. In three populations of an omnivorous lacertid, the Balearic lizard Podarcis lilfordi, we studied chemosensory s ampling and feeding responses to chemical cues from plant and animal foods presented on cotton swabs. Each lizard population is endemic to one islet o ff the coast of Menorca, Balearic Islands, Spain. Lizards in all three popu lations discriminated chemical cues from plant and animal foods from contro l substances. Our results extend findings of prey chemical discrimination a nd plant chemical discrimination in omnivores, increasing confidence that c orrelated evolution has occurred between plant diet and chemosensory respon se to palatable plants. There were no consistent differences among populati ons in tongue-flicking and biting responses to stimuli from flowers of synt opic and allopatric plant species. The lizards may respond to cues indicati ve of palatability in a wide range of plant species rather than exhibiting strong responses only to locally available plant species. Nevertheless, ton gue-flicking and biting frequencies varied among plant species, perhaps ind icating food preferences. In addition, there were differences among populat ions in tongue-flick rates, latency to bite, and licking behavior. Licking was observed in only one lizard population as a response to floral chemical s from only one of the plants species tested, raising the possibility of a population-specific linkage between identification of a particular plant sp ecies and performance of an appropriate feeding response. (C) 2001 Wiley-Li ss, Inc.