CONCLUSIONS:
Overall, we found extensive variation in the influence of incubation temperature on morphological and metabolic phenotypes across populations of alligators. In contrast, the influence of maternal provisioning on hatchling traits was mostly consistent across populations. While the adaptive value of variable plastic responses to incubation temperature was not explicitly tested, latitudinal patterns of some traits (i.e., incubation duration) may imply local adaptation. Nonetheless, variation in the influence of incubation temperature on other traits suggests that selection can act on those relationships, allowing populations to become locally adapted and respond to changing environmental conditions. However, the mechanisms responsible for differential responses to incubation temperature are not known, including the extent to which they are driven by genetic differences or other components of the developmental environment. Determining the causes of these differences, including the developmental mechanisms involved, would provide important insight into how components of the developmental environment and embryonic responses to them influence intraspecific variation and may contribute to adaptive evolutionary change.