Incubation temperature induced phenotypic plasticity in oviparous reptiles: Where to next?

It is now undisputable that incubation temperature induces different phenotypes (sex, body size, body shape, behavior, and locomotion performance) in many if not most oviparous reptiles. These incubation temperature induced differences in phenotype are assumed to result in differential fitness among hatchlings and therefore to play an important role in recruitment of hatchlings and persistence of reptile populations. However, the role of incubation temperature induced differences in hatchling phenotypes in determining hatchling fitness is still under explored and needs more empirical study. This information is especially needed when making predictions on how climate change and its associated nest warming may affect long term persistence of oviparous reptile populations. Curiously, the ontogenetic and physiological mechanisms responsible for incubation temperature induced differences in hatchling reptile locomotion performance are still unknown. In this article, I review the literature on incubation temperature induced differences in hatchling locomotion performance and summarize what is known about this phenomenon and its influence on hatchling fitness. I discuss how the anticipated detrimental effects on hatchling locomotion performance caused by increased nest temperature associated with climate warming could be ameliorated. I also explore the most likely physiological mechanisms underlying incubation temperature induced differences in hatchling locomotion performance and how these mechanisms might be induced. Finally, I highlight current knowledge gaps in our understanding of incubation temperature induced phenotypic plasticity and suggest directions for future research.