Absence of Prey Odor Discrimination by Iguanid and Agamid Lizards in Applicator Tests

Abstract

In experiments designed to discover whether iguanid and agamid lizards use chemical cues to detect and identify prey, three species were exposed to cottontipped applicators bearing water, integumental odorants of domestic crickets, and cologne. None of the three species, the anoline iguanid Anolis carolinensis, the sceloporine iguanid Sceloporus malachiticus, and the agamid Calotes mystaceus, displayed any indication of detecting prey odors. Most individuals in all species did not tongue-flick during trials and none bit applicators. Among the few that did tongue-flick, there were no significant differences in numbers of tongue-flicks emitted during the 60 sec trials. Because observations of feeding behavior of numerous insectivorous iguanids and agamids suggest that they do not investigate chemical prey cues by tongue-flicking or apparent sniffing before attacking prey and because the lizards in the present experiments readily attacked crickets, it is concluded that: 1) stimulation of the vomeronasal system is not necessary to elicit feeding; 2) it is rarely if ever used by these lizards to detect or identify prey; and 3) primary olfaction does not appear to be important to initiation of attack. The iguanids and agamids are sit-and-wait foragers that rush at exposed, visually detected prey and bite without preliminary chemosensory testing; members of several families of autarchoglossans are active foragers that tongue-flick at higher rates while foraging and more often locate hidden prey by chemosensory means. IGUANIDAE and Agamidae are speciose lizard families consisting largely of diurnal sitand-wait predators that appear to rely largely on visual cues for identification of prey. These families are major representatives of the ascalabotan radiation (Camp, 1923) in the New and