Fig. 1. Changes in population size and extinction in response to gradual warming in tropical (dashed lines) and widespread (solid lines) Drosophila species.

Four replicate selection lines of D. bipectinata (green), D. buzzatii (red), D. hydei (yellow), D. melanogaster (orange), D. pseudoananassae (blue) and D. sulfurigaster (purple) were initiated under a fluctuating temperature regime averaging 26 °C (±3 °C) and exposed to a 0.2 °C increase in average temperature every 2 weeks (approximately one generation). Census population size (±SEM) was estimated at the end of each 2-week warming period by assessing the census population size of each replicate line. Information on species’ distributions, subgroup and collection locations is the key. Coloured arrows indicate when selected lines were significantly lower (P < 0.05) than control populations (two-sided, independent samples t-test), and stars indicate when selected lines stopped reproducing/became sterile (scored when pupae were no longer present). Source data are provided as a Source Data file.