Temperatures that sterilize males better match global species distributions than lethal temperatures

Abstract

Attempts to link physiological thermal tolerance to global species distributions have relied on lethal temperature limits, yet many organisms lose fertility at sublethal temperatures. Here we show that, across 43 Drosophila species, global distributions better match male-sterilizing temperatures than lethal temperatures. This suggests that species distributions may be determined by thermal limits to reproduction, not survival, meaning we may be underestimating the impacts of climate change for many organisms. Prediction of current and future species distributions using thermal limits often relies on lethal temperatures, yet many organisms lose fertility at sublethal temperatures. The authors show that distributions of 43 Drosophila species better match male-sterilizing, than lethal, temperatures.