cryb vs. cry+: average BG-luc reported activity in rhythmic isolated body parts. The data shown here were collected under a light-dark cycle (LD 12:12) at a constant temperature of 25°C. The column labeled 'raw data' shows the average plots of luciferase activity for the rhythmic subset of samples as given in Table 1 or Table 2, respectively. Counts-per-second of bioluminescence are plotted on the vertical axis with time in hours given on the horizontal axis. The shaded region around the mean activity line indicates standard error of the mean (SEM). The column labeled 'normalized data' shows plots of the averaged detrended and normalized data as described under Figure 1 (also see Materials and Methods and ). The shaded region represents the SEM. Units on the ordinate are arbitrary and the plot is centered around a mean of 1. Time (in hours) is represented on the abcissa. The column labeled 'autocorrelation' shows correlograms for the normalized data. Correlation coefficients are plotted on the ordinate with a range of values from -1 to 1. The gray region centered around 0 describes a 95% confidence interval. The lag of the autocorrelation function is plotted on the abcissa. An asterisk is placed above the third peak of the autocorrelation function. The value at that point defines the Rhythmicity Index (RI), an estimate of the strength of rhythmicity [27, 31]. When the asterisk is not present, the autocorrelation function indicates a lack of rhythmicity. Values for the RI appear in the lower left corner of these plots along with a related number called the Rhythmicity Statistic (RS). The RS value is the ratio of the RI to the absolute value of the confidence line. This metric indicates that the rhythmicity described by the correlogram is statistically significant when the value is ≥ 1 (see Materials and Methods for more detail). The column labeled 'mesa' shows a spectral analysis of the data that provides an estimate of the period [37, 27]. Spectral density is given in arbitrary units on the ordinate and the range of periods we assess is shown on the abcissa. Asterisks are placed over the highest peak shown in a range between 18–30 hours. Although we take this value as the estimate of circadian period, there may be other periodicities present within the horizontal range (the width) of the peak or elsewhere on the plot and these additional rhythmic components are also present in the data. Absence of an asterisk indicates either the absence of a peak or that any peak within the plot occurs outside the circadian range. Note that the autocorrelation plot is used to determine rhythmicity and mesa is used to provide an estimate of the period only when warranted by correlogram (for more details see Materials and Methods and ). a.) averaged data for cry+ or cryb antennal pairs. These are assessed for rhythmicity on a specimen by specimen basis as tabulated in Table 2. b.) same as a.) for isolated heads as tabulated in Table 1. c.) same as b.) for isolated bodies. This analysis is continued in Figure 4.