Phenotypic integration in response to incubation environment adaptively influences habitat choice in a tropical lizard

Abstract

Phenotypic integration, in which a suite of traits change in a correlated or covarying response to shifts in environmental conditions, may enhance an organism’s fitness. In skinks, rocky environments select for longer limbs and rapid running and climbing. We examined whether differences in nest temperature coincident with specific habitats caused phenotypically integrated effects on morphology, locomotor performance, and behavior in the skink Carlia longipes. Specifically, we determined whether microhabitat choices were integrated with adaptive morphology for each habitat. Using a split-clutch design, we incubated eggs at thermal regimes that mimicked the thermal environments of nests from two habitat types (forest = warm; rocky = cool). Hatchlings from cool incubation environments had longer limbs and greater running and climbing speeds, which are likely to be beneficial for rocky habitats. In addition, individuals from cool incubation environments selected rocky microhabitats more frequently than did hatchlings from warm incubation environments. We demonstrate phenotypic integration in response to nest temperature that affected morphology, performance, and ultimately habitat selection in a way that should increase hatchling fitness.