METZGER, K.A.; Brown University: The effect of food properties on intraoral transport kinematics in lizards

Numerous studies have examined the nature and magnitude of feeding movements during intraoral transport in lizards, but few have quantitatively accounted for the effects of food properties (i.e., mass, hardness, mobility) on the use of the feeding system to process and move prey through the oral cavity. Documenting the kinematic response to altered food properties is important for testing mechanical hypotheses related to feeding, understanding functional or behavioral adaptations for consumption of specific food types, and evaluating the hypothesis that there is a positive relationship between an organism�s dietary breadth and modulatory ability during feeding. In this study, intraoral transport kinematics were evaluated in four species of lizards while food properties were strictly controlled. Food mass, hardness, and mobility were independently varied, and the kinematics of the jaws were compared to evaluate the effect of these properties on the use of the feeding system. There was a definite relationship between food properties and the kinematics of the feeding apparatus, although the strength of this relationship varied for different food properties. In general, altering food mass had a more significant effect on intraoral transport kinematics than did changes in food hardness or mobility. For example, increased food mass was associated with changes in kinematics related to both the overall feeding trial and transport stage (e.g., increased trial duration, increased number of gape cycles) as well as with gape cycle kinematics (e.g., increased slow open phase duration). These results indicate that differences in food properties are a major cause of variation in lizard intraoral transport kinematics that should be quantitatively considered in future studies of feeding in lizards.