Testing the adaptive significance and relative contribution of claws and toepads for clinging performance in Anolis lizards

Abstract Measuring the functional consequences of altered traits can provide not only insight into their adaptive significance but also the relative contribution of multiple traits to organismal performance. We assessed clinging performance of three Anolis lizard species varying in their arboreal habitat use and associated morphological traits. We simulated clinging to leaves and bark, distinct aspects of the arboreal habitat, and repeatedly measured clinging performance with both claws and toepads functional, then while sequentially rendering claws or toepads, and lastly both traits, non-functional. The results suggest the two substantially arboreal species, A. carolinensis and A. distichus, are better adapted to different aspects of the arboreal habitat. Anolis carolinensis toepads performed much better than claws on the smooth dowel, representing the leaves they commonly use, whereas A. distichus claws performed much better than toepads on the rough dowel, simulating the bark on which they are most often found. When comparing claw and toepad variation to a sampling of species in the Anolis radiation, the three species in this study represent only a small subset of morphological variation. Our experimental manipulations support the adaptive significance of claws and toepads for clinging and specialization of different species to distinct aspects of the arboreal environment.