A hidden cost of urban adaptation: decoupling of sprint speed from high wind clinging performance in a lizard

Abstract Anthropogenic change is a near-universal pressure that impacts wildlife across the globe, yet organismal responses to multiple human-driven selective pressures remain poorly understood. Urbanization and hurricanes impose conflicting demands on the locomotor morphology of Anolis lizards, with urban habitats favouring longer limbs and larger toepads, whereas hurricanes select for larger toepads but shorter hindlimbs. Using forest and urban populations of the Puerto Rican crested anole (Anolis cristatellus), we asked whether adaptation to cities entails a cost to clinging performance in hurricane conditions. We measured sprint speed and high wind clinging duration in each individual and used X-ray imaging to identify the skeletal basis of each performance. We found that sprint speed and clinging duration were positively correlated in forest populations but uncorrelated in urban populations, representing a decoupling of ancestral integration in the city. Sprint speed was influenced by variation in limb morphology, whereas clinging performance was relatively insensitive to morphological variation, suggesting that these two performance axes are governed by distinct phenotypes. Taken together, these findings highlight the importance of understanding anthropogenic adaptation as an integrated composite of distinct but interacting forces, with response to selection along one axis potentially constraining adaptive response to another.