Feeding behavior modulation in the leopard lizard (Gambelia wislizenii): effects of noxious versus innocuous prey.

Feeding, a fundamentally rhythmic behavior in many animals, is expected to exhibit modulation with respect to prey type. Using high-speed videography (200 frames(-1)) and kinematic analysis, we investigated prey-processing behavior in the long-nosed leopard lizard (Gambelia wislizenii). The effects of two prey types were examined, innocuous immature crickets (Acheta domesticus) and noxious stinging hymenopterans (honeybees [Apis mellifer] and yellow jackets [Vespula sp.]). Stinging hymenopterans are processed more extensively, with higher gape-cycling frequencies, and for a greater duration than are crickets. Generalized tetrapod feeding models were used as a framework to test the hypothesis that gape profile characteristics are modulated in response to prey noxiousness. Cricket processing generally fits the models, but hymenopteran processing departs from typical model parameters. In particular, the SO phase is absent to barely detectable during hymenopteran processing. This likely represents an effect of extrinsic neural input on a centrally directed rhythmic motor pattern, possibly to avoid being stung. Differences in the capture behavior of crickets versus hymenopterans indicate that G. wislizenii assesses prey noxiousness before physical contact with prey and modifies its capture behavior accordingly. These results add to the growing body of evidence that sensory information can play a critical role in shaping stereotyped rhythmic behaviors in non-mammalian tetrapods.