It is often assumed that populations living in more variable environments are endowed with higher degree of thermal plasticity, but this question is rarely examined eventhough phenotypic plasticity may be an important initial mechanism to counter environmental change. Using populations of Drosophila simulans collected from a latitudinal cline spanning the entire east coast of Australia, Belinda Van Heerwaarden and others assessed thermal plasticity, measured as hardening capacity (the difference between basal and hardened thermal tolerance) for multiple
measures of heat and cold tolerance across both adult and larval stages of development. This allowed us to explicitly ask whether the evolution of thermal plasticity is favoured in more variable, temperate environments. We found no relationship between thermal plasticity and latitude, providing little support for the hypothesis that temperate populations have evolved higher levels of thermal plasticity than their tropical counterparts.
B. van Heerwaarden, B., Lee, R. F. H., Overgaard, J. and Sgrò, C.M. (2014)
No patterns in thermal plasticity along a latitudinal gradient in Drosophila simulans from eastern Australia.