Figure 4. DN1 neuronal activity is sexually dimorphic and can be activated by warm temperatures to enhance fly sleep.

a, Characterization of CaLexA-LUC in freely behaving animals. (Left panel) LUC levels probably reflect neuronal activity in DN1s after CsChrimson stimulation (lower panel). The fold-change of luminescence was calculated as the ratio of the luminescence level after CsChrimson activation to the baseline luminescence level. The red shaded box indicates the 10 min 627 nm light pulse. The genotypes of each line are shown below and n=16 for each groups. Shading represents SEM. (Right panel) CaLexA-LUC shows a dramatic male-female difference in DN1 activity. Averaged bioluminescence levels of 24 CLK4.1M-GAL4>CaLexA-LUC males (red) and females (gray) are plotted. Shaded background depicts dark periods. b, The real-time CaLexA-LUC assay reveals that warmer temperatures promote DN1 activity in the daytime. Black boxes indicate dark periods, white boxes indicate light periods. Flies were maintained at 21°C and then transferred to 30°C. Shading corresponds to SEM. Bioluminescence (arbitrary units); locomotor activity and daytime sleep profile are plotted (left) and quantified (right). n=15 for each group and ‘**’ indicates p<0.001 by paired t-test. c, Blocking DN1 output abolished warm temperature-induced siesta in females. Sleep traces of control and experimental flies are shown on the left. Blue color indicates data at 21°C, and red color indicates data at 30°C. The box plot on right shows the sleep increase for the different groups. Box boundaries represent the first and third quartiles, whiskers are 1.5 interquartile range. n=32 for each group and error bars represent SEM. The genotype for each groups are labeled bellow. ‘**’ indicates p<0.001 by Kruskall-Wallis non-parametric one-way ANOVA with Dunn’s multiple comparisons test.