Figure 8: Correlation between the foraging rates and the impact rates of nest parasites on three successive days with different weather conditions. Values were normalized to nest and 30 minutes of observation time. On day 1, the bees obeyed the simple rule that foraging activity decreases with increasing parasite impact (regression function: Fout=-0.4903*Ip+1.6834; n=9; r=0.892; P<.001; shown by a white stripe in the correlations graphs of all experimental days). The graphs indicate that averaging of the daily rates of bee and parasite activities is crucial, in particular due to the massive influence of weather conditions.