Mean number of honeybees entering with pollen.

Bars show the mean number of honeybees (mean ± se) entering with pollen under different treatments (i.e. mean number of pollen foragers returning within 5 min). Plotted data are means and standard errors indicate significant differences. Post hoc testing created the groups that capital letters indicate the significance level P < 0.01 and small letters indicate the significance level P < 0.05.