Number of pupae raised by worker groups fed different diets over a 12-week period. The maximal possible number of pupae is 90. Differences across diets were significant (ANOVA: p < 0.001, F5,42 = 13.338; see Results). Groups differing significantly from each other in Tukey HSD posthoc test are marked with different letters above box-plots. Medians are given in box-plots, and an outlier is marked with a circle. Diets: C = control (Bhatkar agar and honey water), A = artificial diet with essential amino acids, AR = artificial diet plus antibiotic Rifampicin, B = artificial diet without essential amino acids, BR = artificial diet without essential amino acids but with antibiotic Rifampicin, S = sucrose solution only (20% w/v).