Honeybees (Apis mellifera) from a line which had been selected for high pollen-hoarding behaviour (HPH) hoarded more pollen than bees from a low pollen-hoarding line (LPH) when they were kept in observation colonies with known amounts of brood. These differences were not found when brood was in the egg stage and pollen stores were small, but were large and significant when brood was in the larval stage and pollen stores was more abundant. Differences in amounts of stored pollen that were established between the lines during the larval stage were maintained after brood cells were capped, but amounts of pollen stored did not change significantly. HPH bees also hoarded more pollen in the absence of brood. The two lines used similar amounts of pollen and reared similar amounts of brood. Mortality of the LPH bees was higher and varied significantly more than that of the HPH bees. It is suggested that bees which hoard a large amount of pollen are either less inhibited from collecting pollen by the presence of stored pollen or more stimulated to collect pollen by its absence.