VANHOOYDONCK, B.*; HERREL, A.; IRSCHICK, D.J.; University of Antwerp, Antwerp, Belgium; University of Antwerp, Antwerp, Belgium; Tulane University, New Orleans: Effects of substrate diameter on acceleration capacity in Anolis lizards

Although lizards are often considered model systems for the study of locomotor performance and ecology, little is known about the effect of substrate characteristics (e.g. diameter, texture) on performance. This seems especially relevant in the context of unsteady locomotor behaviours, such as acceleration, as in nature lizards typically use short bursts of locomotion on a variety of substrates to escape predators and/or to capture prey. In this study, we measured acceleration capacity and running speed in three species of Anolis lizards on two dowels of different diameter. The species were chosen to represent three ecomorphs, differing in their natural substrate usage (i.e. trunk-ground, trunk-crown, twig). The trunk-ground anole, Anolis sagrei, showed the highest level of acceleration capacity followed by the trunk-crown anole, A. carolinensis. The twig anole, A. valencienni, performed poorest on both substrates. In all three species, acceleration capacity declined with dowel diameter. Sprint speed, however, was affected to a varying degree in the different species. Whereas sprint speed declined dramatically in the trunk-ground anole, no efffect of dowel diameter on sprint speed was observed in the twig anole. Despite being the best accelerator, A. sagrei appears unable to continue to accelerate beyond the first step on the narrowest dowel. A. valencienni, on the contrary, manages to accelerate over several steps on both surfaces. Our data suggest that initial burst acceleration capacity might trade-off with stability on narrow surfaces thus compromising sprinting ability in Anolis lizards.