Histochemical and histophysical aspects of silk secretion in Melipona quadrifasciata (Hym., Apoidea)

Summary Acid and neutral polysaccharides exist in the secretion of the silk glands of Melipona quadrifasciata during the entire functional stage, except in the late 5th instar. However, only from the 3rd instar on is a molecularly oriented structural protein present. The following evidence indicates that this protein is not collagen: (1) the optical sign of its birefringence does not become reversed after von Ebner's reaction, and (2) its secretion can be detected when the cell nucleus attains a ploidy degree optimal for secretory activity. This is at first observed in the distal part of the glands and then throughout the organ.Stipendiat der Alexander von Humboldt-Stiftung.