Tree selection is linked to locomotor performance and associated noise production in a lizard

Microhabitat preference can be an important determinant of individual fitness. Differential use of microhabitats (such as substrate type) can confer or facilitate increased ability to evade or escape predators, and catch prey, for example by influencing sprint speed and noise produced by movement. However, there have been few studies that demarcate whether substrate use influences traits like these. Additionally, the importance of auditory crypsis and locomotor performance for microhabitat selection has been historically under-studied, especially when compared to the importance of facilitating visual crypsis. We investigate substrate (tree) type use, and the influence of substrate types on both sprint performance and level of noise produced by movement, in fence lizards (Sceloporus undulatus). In our study sites, fence lizards inhabit mixed woodland where deciduous and coniferous trees exist at approximately equal frequency. We show a strong bias in tree use, with lizards being found more frequently on deciduous trees. Using acoustic and video recordings of lizards moving on trees of both types, we demonstrate that lizards sprint faster and their movement appears to generate less noise on deciduous trees, providing a possible basis for their increased use of this tree type. These data suggest that lizards use substrates on which they are more likely to evade auditory detection and can sprint quickly to refuge or capture prey. We conclude that factors other than visual camouflage may be important in determining substrate use and should also be considered in studies of microhabitat selection.