Nurse bees support the physiological development of young bees (Apis mellifera L.)

Newly emerged worker honeybees (focal bees) were caged individually for 8 days either isolated or together with one companion bee of known age (2–30 days) taken from a colony. The companion bee was replaced every 2nd day. After 8 days, various parameters were investigated in the focal bees as indicators of the level of development. Focal bees which had been caged with 6-day-old companion bees were better developed than isolated focal bees, newly emerged bees, or focal bees caged with almost all other ages of companion bees. They had hypopharyngeal glands that were larger and contained more protein, their thoraces had a higher protein content, and they had a higher rate of proteolytic activity in the midgut. Although the focal bees were supplied with pollen as well as honey, they consumed only small amounts of pollen. We attribute their better development to their having been fed worker jelly by the accompanying companion bees. The 6-day-old companion bees consumed high quantities of pollen and spent more time (18.7 ± 11.85 s/h) feeding focal bees than 12-day-old bees (6.5 ± 4.09 s/h) or foragers (no feeding of focal bees). The results show that even under such artificial conditions, the exchange of food (trophallaxis) promotes the development of young honeybee workers. Accepted: 26 February 1999