Microgeographic variability in locomotor traits among lizards in a human-built environment

9 Microgeographic variability in fitness-relevant traits may be more common than 10 previously appreciated. The fitness of many vertebrates is directly related to their locomotor 11 capacity, a whole-organism trait integrating behavior, morphology, and physiology. Because 12 locomotion is inextricably related to context, I hypothesized that it might vary with habitat 13 structure in a wide-ranging Greek lizard, Podarcis erhardii. I compared lizard populations living 14 on human-built rock walls, a novel habitat with hard vertical structure, with nearby 15 populations naive to human-built infrastructure that live in flat, loose-substrate habitat. I 16 tested for differences in morphology, behavior, and performance. Lizards from built sites 17 were larger and had significantly (and proportionately) longer arms and legs. The differences 18 in leg morphology were especially pronounced for distal components, the foot and longest 19 toe. These morphologies facilitated a significant behavioral shift to jumping across the rocky 20 experimental substrate. I found no difference in maximum velocity between these 21 populations, however females originating from wall sites potentially accelerated faster over 22 the rocky experimental substrate. The variability between these closely neighboring 23 populations suggests that the lizards inhabiting walls have experienced a suite of trait 24 changes enabling them to take advantage of the novel habitat structure created by humans. 25