Effect of habitat use and coadaptive responses on the thermal physiology of two related species of lizards living in high mountain environments

Abstract

Coadaptation processes evolve when the interaction among behavior, physiology, and morphology produces positive effects on the fitness of organisms. In this context, the coadaptation of thermal physiology and behavioral thermoregulation strategies in ectothermic organisms should be prominent, mainly due to their thermal dependence and the influence of body temperatures on physiological performance, ecological interactions, and fitness. Therefore, we aimed to investigate the role of microhabitat use in two high-mountain lizard species (Abronia genus) with different habitat preferences (terrestrial and arboreal) on the degree of coadaptation between thermal physiological parameters and thermoregulatory strategies. We found that environmental pressures, driven by habitat use and seasonality, result in differential responses in both behavioral thermoregulation strategies and the physiology of these species. This high response capacity has allowed them to compensate for thermal fluctuations in their microhabitats and has, to some extent, promoted the coadaptation of selected temperature (T_sel), thermal optimum (T_o), and thermal performance breadth (B₈₅), along with thermal limits and thermoregulatory strategies. Our findings support the hypothesis of labile physiology, as both Abronia species responded to divergent thermal regimes by adapting their thermal physiology.