Facultative frugivory in the cape flat lizard, Platysaurus capensis (Sauria: Cordylidae)

Platysaurus capensis is an omnivorous lizard that feeds on Namaqua figs (Ficus cordata) when they are available. We studied fig-feeding behavior of male, female, and juvenile lizards at Augrabies Falls National Park, South Africa. Figs were available in three discrete classes depending on their state of hydration/ripeness. Focal sampling and feeding trials were used to quantify fig handling and feeding behavior. Adult P. capensis usually ate the entire fig, but handling times were significantly shorter for males than females. Adults frequently used the rock substrate to break figs whereas juveniles could only eat figs already broken. (Figs were often broken open by birds and other lizards.) Juveniles usually ate only part of each fig, often just the seeds. Juveniles also used a head-shaking behavior rarely seen in adults, to break off manageable pieces of figs. Platysaurus capensis recognized figs away from fig trees, indicating a flexible recognition ability. During foraging in debris lizards stayed close to exposed rock. Interference competition between lizards was strong, resulting in individuals running to areas free of other lizards to avoid harassment during feeding. Adults were more likely to approach feeding lizards than juvenile. Lizards also exhibited a strong sensory bias for moving objects, selecting moving unripe (inedible) figs over stationary ripe figs. Adult lizards chose large ripe figs over two classes of older, more desiccated figs; ripe figs were consumed disproportionately to their availability. Experiments using paint-manipulated ripe and unripe figs showed that, when size is controlled, lizards use color and/or brightness as an initial indicator of fig quality. Visual evaluation was often followed by tongue-flicking or nudging with the snout. This study represents the first detailed examination of feeding behavior in a cordylid lizard.