Fig. 4. Body size and circadian rhythms in locomotor activity for B. terrestris workers in an oscillating (LD) laboratory environment. (A) Actogram for a small bee. Details of the actogram as in Fig. 3A. The background of the plot delineates illumination regime: white background, light phase; gray background, dark phase. This individual emerged from the pupa at day 1, had a nocturnal activity pattern for the first 8 days, and then switched to a diurnal activity pattern. Anticipation of light on is evident at 12 days of age (black arrow). (B) Development of diurnal rhythms for large (top) and small (bottom) workers. Filled bars, significant rhythms with peak activity during the dark phase; open bars, peak activity during the light phase. Asterisks and plus signs indicate days in which there were significant differences in the proportion of small and large bees that were active during the light or dark phase, respectively (Fisher's 2x2 Exact Test, P<0.05). (C) Anticipation of light transition in small (continuous line, N=14) and large (dotted line, N=33) workers. Included are bees with nocturnal activity that anticipated light-off and bees with diurnal activity that anticipated light-on (Survival Analysis, P>0.05).