COMPARATIVE-STUDY OF DIGESTIVE CELLS IN DIFFERENT MIDGUT REGIONS OF STINGLESS BEES (HYMENOPTERA, APIDAE, MELIPONINAE)

Ultrastructure of the digestive cells was analyzed in three midgut reg ions (anterior, middle and posterior) of stingless bees. Variations oc curs in the presence of lipid inclusions in the cells from posterior m idgut and presence of double-membraned vesicles associated to microvil li in the anterior midgut. However, basal plasmic membrane infoldings and augmentation of surface area achieved by microvilli ale very simil ar in all midgut regions. These results not supported the existence of fluid fluxes in the ectoperitrophic space and suggest that digestive cells in stingless bees are polifunctional, that is, there is not midg ut region specialized in secretion ol absorption as observed in other insects.