Analysis of the defecation cycle in gon-2(RNAi);gtl-1(RNAi) animals reveals compensatory behaviour in the oscillator. A: A histogram showing the frequency of the combinations of the direction of the change in cycle length for pairs of cycles. For each cycle we determined whether the period increased (represented by +), decreased (-) or remained constant (0). We then counted the number of cycle pairs which fell into each possible class. Those of classes "00", "0+" and "0-" are not shown. The frequency is shown as proportion of the total number of cycle pairs included in the analysis. B: A scatter plot of the change in period time in one cycle pair compared to the subsequent cycle pair for gon-2(RNAi);gtl-1(RNAi) animals. T(n) is the period of the cycle n. Linear regression was used to derive the line which, is shown with 95% confidence limits (dashed lines).