PhD Candidate University of Colorado Boulder, Colorado
The Climate Variability Hypothesis (CVH) predicts that in environments with more variation in temperature, species will evolve broader thermal tolerances. It is energetically costly to be tolerant of a broad range of temperatures and selection should favor organisms with thermal tolerances closely matching temperatures they experience. Thus, it is predicted that both upper and lower thermal limits will decline with elevation to match environmental temperatures. Additionally, thermal limits may vary along the elevational range of a species. At higher elevations where temperatures are generally colder, individuals may be more sensitive to hotter temperatures but able to withstand colder temperatures. Lower thermal limits are often more labile than upper thermal limits, meaning that lower limits are more likely to change with elevation. This project aims to identify if carrion beetle elevational distributions are linked to temperature by investigating the relationship between elevation and thermal limits. Using Colorado carrion beetles as a study system, we plan to compare thermal limits of carrion beetles from five sites along an elevational gradient, measured as the air temperature when the insect loses coordination at both higher and lower temperatures. We expect that temperatures across elevational gradients affect thermal limits in a way consistent with the CVH—species with broader climactic niches exhibit broader thermal tolerance. Validating the CVH in untested taxa and gaining a better understanding of the mechanisms underlying thermal limit variation will enable better predictions of insect responses to climate change, and ultimately improve conservation of at-risk species.
