Ultrastructure of the midgut epithelium of Meliponinae larvae with different developmental stages and diets

The comparative study of the ultrastructure of the midgut epithelium of sti ngless bee larvae that eat plant protein (pollen) and animal protein (carri on) throughout the larval phase, shows variations in the digestive cells th at are only relative to larval aging and not to the type of larval diet. Th e cells of older larvae present a cytoplasm with empty spaces that result f rom emptying of lipid and glycogen stocks, and the presence of autophagic v acuoles. These results are discussed in relation to the hypothesis that var iations in the digestive tract of insects may be associated with different diets or phylogeny. We conclude that different diets do not determine cell morphology adaptations in the studied species. As the variations in the ult rastructure of the midgut epithelium are the same in all studied species, i ncluding the necrophagous species Trigona hypogea, throughout the larval st age, this sequence of changes seems to be due to different physiological st ate during larval development.