Fig. 6: Only ls-tim flies are able to synchronise to Northern latitude summer conditions.

a Changes in daily light intensity (left graph) and temperature (right graph) recorded within the incubator programmed to reflect summer conditions in Oulu, Finland (65° North). b Group actograms and corresponding histograms of the last three days of one representative experiment in semi-natural Oulu conditions. White areas and bars: periods of light, and light ramping. Grey areas and bars, periods of 0.1 lux, reflecting civil twilight. Triangles under the histograms indicate the initiation of the light ramping (increase and decrease between 0.1 lux and 200 lux). The blue line above the histograms indicate the temperature ramping (between 12 and 19 °C) and the blue diamonds indicate SEM. N (Canton S): 19; (w⁺; s-tim [Hu]): 20; (s-tim; cry⁰²): 21; (tim^KO): 14. c Median of normalised activity of independent experiments combined during the 6th day of Oulu condition. Yellow and blue lines indicate light and temperature ramping, respectively. N (Canton S): 38; (w⁺; s-tim [Hu]): 39; (s-tim; cry⁰²): 41; (tim^KO): 33. Source data are provided as a Source Data file.