Pollen and utilization in worker honeybees (apis mellifera carnica): Dependence on individual age and function

The pollen content of the gastrointestinal tract of honeybee workers was investigated in the morning before the beginning of flight activity. It was low in young bees, largest in about g-day-old nurse bees and declined to minimal amounts in foragers. In all age groups, the amount of pollen in the crop was small but that in the midgut was representative of the age-related status of the bee in the system of division of labour. It could be correlated with the developmental stage of the hypopharyngeal glands and to the known content of proteolytic enzymes in the midgut. The higher pollen content of the rectum followed the same pattern as that in the midgut. The predominant two pollen species (Castunea sutiua MILL. and Trifolium repens L.)were digested more efficiently by young bees than by foragers. The species of pollen found in bees from all age groups was constant and similar to the species of comb-stored pollen. The known age structure of the colonies permits an estimation of the amount of pollen in the gastrointestinal tract of all workers in a normal-sized colony. It was 80.7 and 107.1 g in the two hives investigated. The pollen requirement for a year could be calculated from the average pollen congent of a bee and the estimated bee-days per colony. It was 13.4 and 17.8 kg in the two hives.