Figure 1.

The effect of age and brood on circadian rhythms in locomotor activity in B. terrestris queens. (a) Ontogeny of circadian rhythms in locomotor activity for virgin gynes (experiment 1: trial 1, n = 21; trial 2, n = 8 and experiment 2, n = 12). A bee that showed significant circadian rhythms during two consecutive 3 day intervals was considered rhythmic thereafter. (b) The percentage of queens with circadian rhythms in locomotor activity, during days 1–4 (open bars) and 5–8 (filled bars) (Pearson χ², p = 0.01 for days 1–4; p < 0.001 for days 5–8). (c) The power of circadian rhythms in locomotor activity for rhythmic bees (mean ± s.e.), during days 1–4 (open bars) and days 5–8 (filled bars; Kruskal–Wallis tests, p = 0.04 for days 1–4; p = 0.03 for days 5–8). Numbers inside bars depict sample size. The figure shows only the data for queens for which the presence of brood did not change during the course of the experiment. Data for additional queens are summarized in the electronic supplementary material, table S2. (a) Circles with dashed lines, trial 1; triangles with dashed lines, trial 2; squares with solid line, experiment 2.