SYNTHETIC QUEEN MANDIBULAR GLAND PHEROMONE (QMP) WAS APPLIED TO HONEY BEE COLONIES TO TEST TWO HYPOTHESES: (i) QMP acts like a primer pheromone in the regulation of age-related division of labor, and (ii) this primer effect, if present, varies in three strains of workers that show genetically-based differences in their retinue attraction response to QMP (a pheromone releaser effect). Strains of workers that were high, or low in their response to QMP in a laboratory bioassay, as well as unselected 'wild-type' workers, were fostered in queenright colonies with or without supplemental QMP. Effects of QMP on foraging ontogeny and juvenile hormone III (JH) blood titers in worker honey bees were measured. Bees in QMP-supplemented colonies showed significant delays in foraging ontogeny, and foraging activity was reduced. They also had significantly lower JH titers, although the titer curves were somewhat atypical. There were no differences in foraging ontogeny or JH titers among the three strains. We conclude that (i) QMP can delay the ontogeny of foraging by some mechanism that suppresses JH production, (ii) this QMP primer response is independent of the retinue releaser response, and (iii) QMP can play an important role in regulating division of labour.