Mean survival (at final census) of Aphaenogaster rudis (upper panel) and Temnothorax curvispinosus (lower panel) as a function of rearing temperature. Error bars represent 95% binomial proportion confidence intervals. Lines are colored by source locations such that the coolest location is tan and the warmest is dark red. Colors represent mean summer temperatures at source locations: A. rudis – dark red, 26.1°C; orange-red, 24.1°C; tan, 18.5°C; T. curvispinosus – dark red, 24.8°C; red, 23.7°C; orange, 22.4°C; yellow, 20.4°C; tan, 18.5°C. Points are jittered along the x-axis so that points of overlap between different source locations can be visible. Rearing temperatures were 21°C, 26°C, and 31°C.