SummaryThe age of the workers influenced their behaviour towards a virgin queen introduced to them. Young workers (7 days old) accepted an introduced virgin queen, whereas older workers (14 or 21 days) usually rejected her. Workers 14 days old were more aggressive than those 21 days old. The“aggression score”increased linearly in workers from 8 to 12 days old. The number of pollen collectors also increased linearly throughout this period, but the number of guard bees was greatest at 10 days.