Absence of discriminatory tongue-flicking responses to plant chemicals byhelodermatid lizards.

摘要

Herbivorous and omnivorous lizards discriminate between palatable plant food and control stimuli by tongue-flicking (Cooper and Alberts, 1990; Cooper, 2000a, 2000b, 2000c; Cooper and Flowers, 2000). Because tongueflicking serves to sample chemicals from environmental substrates for delivery to the vomeronasal organs, and because prey chemical discrimination in lizards requires vomerolfaction (Cooper and Alberts, 1991), plant chemical discriminations presumably are vomerolfactory. In snakes there is a close correspondence between diet and strength of chemosensory responses to potential foods (Burghardt, 1970; Arnold, 1981; Cooper et al., 2000a), but no such correspondence has been established in lizards. Because the large majority of lizards consume little or no plant matter (Iverson, 1982), herbivory may afford an opportunity to examine a similar correspondence between diet and chemosensory responsiveness in lizards. To assess whether such correspondence occurs, WEC has undertaken comparative studies to assess responses by herbivorous and omnivorous lizards to plant chemicals and prey chemicals. Responses to plant chemicals by species that do not eat plants must be determined to learn whether plant chemical discriminations are acquired in association with plant consumption.