Fig. 1: Spontaneous sleep in seven Drosophila species.

a Partial evolutionary tree of the Drosophila genus, highlighting in bold the seven species used in this study and their ecological niches (right). b World map indicating the geographical ancestral range of each of the species employed in this study. c Spontaneous, baseline sleep profile of the seven species across the 24 h period in females (left) and males (right). The white-dark bars under this all figures indicate light-dark periods. ZT: zeitgeber or relative time. The legend below the figure indicates the color code used through the rest of the paper. d power analysis of the circadian period of activity in constant dark conditions in all seven species. The shaded area in (c) and (d) indicate the bootstrapped 95% confidence intervals. e Quantification of sleep amount during the day (ZT 0–12, sun icon) and during the night (ZT 12–24, moon icon) in females (left, pink) and males (right, blue) for all seven species. The pink and cyan rectangles indicate the number of individuals for females and males respectively. The shaded boxes indicate the median and the interquartile range, the whiskers define minimum and maximum values; the dots indicate the single data points. f Schematics of the experimental analysis in (g, h). Ethoscopes collect activity data in real time and deliver air puffs or mock stimuli after random periods of inactivity. A hidden Markov chain model trained on species-specific data classifies sleep stages. g The transition parameters of the D. melanogaster trained model. h The probability of movement following the air puffs (colored boxes) or the mock stimuli (gray boxes) in all seven species, by sleep stage. N = 46 male individuals for each species. The shaded boxes indicate the median and the interquartile range; the dots indicate the single data points and define minimum and maximum values.