SummaryThe recruiting behaviour was investigated of honeybees whose inclination to forage received one of three levels of partial reinforcement, or continuous reinforcement, at feeding dishes. Honeybee foragers receiving an intermediate level of partial reinforcement recruited more new workers than foragers receiving either continuous reinforcement or less rewarding levels of partial reinforcement. It is suggested that the evolution in some plants of intermediate levels of partial reinforcement (by their nectar production) ensured maximal pollination, both by its direct effect on foraging behaviour and also indirectly by stimulating recruiting behaviour in the foragers.