Most of the analytical tools outlined below have been applied individually to previous Drosophila circadian rhythms data, most saliently MESA and autocorrelation were used in both behavioral and molecular studies [39 ,15 (link),13 (link)]. Butterworth filters have been employed in studies of locomotor rhythms [13 (link)]. The Rhythmicity Index (RI) was devised to facilitate studies on Drosophila heart function behavioral studies [46 ,25 (link)] and extended to the Drosophila luciferase assay [13 (link)]. Phase coherence and comparison analyses [32 (link)], have appeared in Yang et al. [17 (link)]. Cross correlation [37 ] has not been employed previously for the study of biological rhythms.