Data from: Evolution and plasticity of thermal performance: An analysis of variation in thermal tolerance and fitness in 22 Drosophila species

The thermal biology of ectotherms is often used to infer species’
responses to changes in temperature. It is often proposed that temperate
species are more cold-tolerant, less heat-tolerant, more plastic, have
broader thermal performance curves (TPCs), and lower optimal temperatures,
when compared to tropical species; however, relatively little empirical
work has investigated these expectations. Here we measure thermal
tolerance limits and thermal performance of the fitness components
viability, developmental speed, and fecundity at seven temperatures in 22
species of Drosophila reared at a common temperature. For 10 of these
species, we also measured thermal tolerance and thermal performance
following developmental acclimation to three additional temperatures.
Using these data, we test several fundamental hypotheses about the
evolution and plasticity of heat and cold resistance and thermal
performance. We find that cold (and to a lesser degree heat) tolerance
varied between the species in a predictable pattern. This confirms the
marked effect of evolutionary adaptation and acclimation on thermal
tolerance. However, contrary to expectation, find that the breadth of
thermal performance in fitness traits were similar in temperate,
widespread and tropical species and we also find that the plasticity of
TPCs is constrained. These data support the idea that thermal tolerance
limits have evolved in response to extreme environmental conditions that
limits species persistence whereas the temperature range for optimal
thermal performance is likely under selection by the temperatures that
prevail during the more benign seasons. Further, it calls to question the
utility of TPCs in inferring ecological adaptation. We conclude that the
thermal performance of fitness traits in Drosophila species are temporally
and spatially stable and that thermal tolerance varies considerably across
latitudes.