Figure 2
Daily peaks in planarian activity. Daily peak activity times for the three species examined, calculated as average angular-transformed hourly data. The angular concentration (r c), an inverse measure of individual variability, also is given. Pooled standard error, used to separate significantly different averages [49], was not calculated because species-specific daily peak activity times were not statistically separated (second-order Hotelling test: F = 1.407, p = 0.185).