Peritrophic membrane protein in the larval stingless bee Melipona quadrifasciata anthidioides: immunolocalization of secretory sites

The origin of the peritrophic membrane (PM) in bees is still a matter of debate. It is either of type I (synthesized by the entire midgut epithelium) or of type II (released from the anterior midgut end). The present study identified secretory sites of peritrophin-55 kDa, a PM protein in larvae of Melipona quadrifasciata anthidioides. Peritrophin-55 was isolated from PMs and was used for the production of a polyclonal antibody. Our study demonstrates the presence of peritrophin-55 in vesicles and on microvilli of digestive cells and in the PM. It suggests that the PM is of type-I, being specific for the larval phase of this stingless bee.