OLFACTION AND PREDATOR DETECTION IN COLEONYX BREVIS (SQUAMATA, EUBLEPHARIDAE), WITH COMMENTS ON THE FUNCTIONAL-SIGNIFICANCE OF BUCCAL PULSING IN GECKOS
Be. Dial et K. Schwenk, OLFACTION AND PREDATOR DETECTION IN COLEONYX BREVIS (SQUAMATA, EUBLEPHARIDAE), WITH COMMENTS ON THE FUNCTIONAL-SIGNIFICANCE OF BUCCAL PULSING IN GECKOS, The Journal of experimental zoology, 276(6), 1996, pp. 415-424
Squamate reptiles rely heavily on two nasal chemical senses in directi
ng most of their behavior: nasal olfaction and vomeronasal function. F
or most behaviors in most species, the vomeronasal system is the predo
minant sense. It has been suggested, however, that geckos are unusual
in the extent to which they rely on nasal olfaction rather than vomero
nasal function. In this study, we use defensive tail display as a beha
vioral bioassay to examine the context and relative use of olfaction v
s. vomeronasal function in a eublepharid gecko, Coleonyx brevis. When
presented with appropriate snake-predator skin chemicals in the absenc
e of relevant visual stimuli, C. brevis exhibits a defensive tail disp
lay that has been shown to be adaptive in defending against snake pred
ators. We demonstrate that olfactory cues alone are sufficient to prov
oke the behavior and that geckos precede the display in many cases wit
h ''buccal pulsing,'' a behavior that we suggest is an olfactory sampl
ing mechanism analogous to mammalian sniffing. Our results support the
gecko-olfaction hypothesis and demonstrate that geckos use nasal olfa
ction to discriminate among potential predator species. We discuss alt
ernative hypotheses for the origin of species-specific, chemosensory p
redator identification in Coleonyx. (C) 1996 Wiley-Liss, Inc.