Protein requirements in larvae and adults of Scaptotrigona postica (Hymenoptera : Apidia, Meliponinae): midgut proteolytic activity and pollen digestion

The number and degree of digestion of pollen grains in the midgut and rectu m, the midgut proteolytic activity and the time of pollen grain passage thr ough the digestive tract in the stingless bee Scaptotrigona postica (Latrei lle) have been analyzed. The results show similar protein requirements amon g larvae, nurse bees and queens, as well as between forager bees and old ma les, but these requirements are higher in individuals from the former group s than in those from the latter. Although protein requirements have been de monstrated to vary according to a bees activity in the colony, they are sim ilar among bees from different castes or sexes. These changes in feeding be havior are related to the bee's function and to less competition for nouris hment among individuals of the colony. It is also noted that pollen grains took between 6 and 28 h to pass through the digestive tract. Pollen grains are irregularly accumulated in the various regions of the midgut, which may reflect functional differentiation throughout the midgut. (C) 2001 Elsevie r Science Inc. All rights reserved.