Male fertility thermal limits predict vulnerability to climate warming

• Published in: Nature communications Vol. 12; no. 1; pp. 2214 - 11
• Main Authors: van Heerwaarden, Belinda, Sgrò, Carla M.
• Format: Journal Article
• Language: English
• Published: London Nature Publishing Group UK 13.04.2021; Nature Publishing Group; Nature Portfolio
• Subjects: 631/158/2165; 631/158/672; 631/158/857; 631/181/2475; 64; 64/24; Adaptation, Physiological; Animals; Biological evolution; Climate Change; Climate prediction; Cytotoxicity; Drosophila; Drosophila - physiology; Ecosystem; Endangered & extinct species; Environmental changes; Evolution; Extinction; Female; Fertility; Fertility - physiology; Fruit flies; Global Warming; Hot Temperature; Humanities and Social Sciences; Insects; Lymphocytes T; Male; Males; multidisciplinary; Science; Science (multidisciplinary); Species extinction; Temperature; Thermotolerance - physiology; Threatened species; Tropical Climate
• ISSN: 2041-1723; 2041-1723
• DOI: 10.1038/s41467-021-22546-w

Forecasting which species/ecosystems are most vulnerable to climate warming is essential to guide conservation strategies to minimize extinction. Tropical/mid-latitude species are predicted to be most at risk as they live close to their upper critical thermal limits (CTLs). However, these assessments assume that upper CTL estimates, such as CTmax, are accurate predictors of vulnerability and ignore the potential for evolution to ameliorate temperature increases. Here, we use experimental evolution to assess extinction risk and adaptation in tropical and widespread Drosophila species. We find tropical species succumb to extinction before widespread species. Male fertility thermal limits, which are much lower than CTmax, are better predictors of species’ current distributions and extinction in the laboratory. We find little evidence of adaptive responses to warming in any species. These results suggest that species are living closer to their upper thermal limits than currently presumed and evolution/plasticity are unlikely to rescue populations from extinction. Trait-based approaches assume upper critical thermal limits (CTLs) are good predictors of climate change vulnerability. Here, the authors show that male fertility thermal limits, which are lower than CTLs, are better at predicting Drosophila extinction in the lab, suggesting species may be living close to their thermal limits.