The effects of substratum on locomotor performance in lacertid lizards

Locomotion is important to animals because it has direct implications for fitness through its role in predator escape, prey capture, and territory defence. Despite significant advances in our understanding of animal locomotion, studies exploring how substrate properties affect locomotor performance remain scant. In the present study, we explore how variation in substrate (sand, slate, cork) affects locomotor performance in lacertid lizards that differ in morphology. Moreover, we explore whether substrate effects are the same for different types of locomotor performance (speed, acceleration, and stamina). Our results show that the substrate affected most types of locomotor performance studied but not always in the same way. Although substrate effects were species-dependent for the maximal speed over 50cm and the distance run to exhaustion, this was not the case for acceleration capacity. These results suggest that substrate texture differentially affects burst performance vs. longer duration measures of locomotor performance. Finally, straightforward relationships between habitat use and the substrate on which performance was maximized were not observed. This suggests that the evolution of locomotor capacity is complex and that animals may show compromise phenotypes allowing them to deal with a variety of substrates in their natural environment.