Abstract

Rapid and ongoing climate change is causing a complete redistribution of life on Earth. To predict species’ geographic responses to climate change, it is critical that we establish the role of species’ thermal tolerances in shaping their climatic envelopes. Using experimentally-derived measures of thermal limits and a database of georeferenced occurrence records, we test whether thermal limits can predict the hottest and coldest temperatures experienced within the geographic distributions of 13 North American odonate species. We measure thermal limits in both odonate larvae and adults to account for potential life stage-related differences. Lastly, we use a time-calibrated phylogeny of North American odonates to estimate the effects of evolutionary history on the relationship between species’ thermal and climatic limits. We find that, even after accounting for ontogenetic differences and phylogeny, thermal limits do not translate into climatic limits. Further, we determine that species’ thermal limits are constrained by phylogeny, while climatic limits appear to have evolved free from phylogenetic associations. This suggests that the evolvability of odonates’ thermal limits is limited and that currently, species are in disequilibrium with their environment. Additionally, other traits or processes, such as biotic interactions, are potentially shaping odonates’ geographic distributions. In the face of climate change, odonates are unlikely to adapt to novel environmental conditions and thus will likely have to continue to shift their geographic distributions in order to track their ancestral thermal niches. Further, purely climate-based models will likely be insufficient for predicting odonates’ geographic responses to climate change.