Evidence for lower plasticity in CTMAX at warmer developmental temperatures

Understanding the capacity for different species to reduce their susceptibility to climate change via phenotypic plasticity is essential for accurately predicting species extinction risk. The climatic variability hypothesis suggests that spatial and temporal variation in climatic variables should select for more plastic phenotypes. However, empirical support for this hypothesis is limited. Here we examine the capacity for ten Drosophila species to increase their critical thermal maxima (CTMAX) through developmental acclimation and/or adult heat hardening. Using four fluctuating developmental temperature regimes, ranging from 13‐33 °C, we find that most species can increase their CTMAX via developmental acclimation and adult hardening, but found no relationship between climatic variables and absolute measures of plasticity. However, when plasticity was dissected across developmental temperatures, a positive association between plasticity and one measure of climatic variability(temperatur...