Fig. 4

Fly locomotion changes in darkness. A Tracks number increased about 3 time higher in darkness. B representative track event plot for drosophila in darkness or under normal lighting. C Track straightness decreased in darkness. D Long stop episodes duration decreased in darkness. E Long stop episodes numbers decreased in darkness. F Max. velocity increased in darkness. G Move time decreased in darkness. H Avg. distance from the arena center decreased in darkness. I Movelength ratio at edge decreased in darkness. J, L The time proportion spent at the edge (J) and angular velocity (L) were changing over the videotaped 30 min for drosophila in darkness or under normal lighting. K Difference of time prop. spent at edge of flies under normal illumination and darkness was eliminated at end of the video. M Difference of avg. angular velocity of flies under normal illumination and darkness was eliminated at end of the video. Statistical analysis: Welch Two Sample t-test was used for comparisons between two groups. *P < 0.05, **P < 0.01, ***P < 0.001. Non-significant test was not annotated in the graph for brevity. n = 26 videos for male w¹¹¹⁸ flies under normal illumination, n = 27 videos for female w¹¹¹⁸ flies under normal illumination, n = 27 videos for male w¹¹¹⁸ flies in darkness, n = 27 videos for female w¹¹¹⁸ flies in darkness were recorded and analyzed. All videos recorded were from three independent experiment replicates