Abstract: The fat body of insects is an important tissue of material reserves and intermediary metabolism. The proliferation and apoptosis pattern of the fat body in workers of the Italian honeybee, Apis mellifera ligustica, was comparatively studied by using micromorphological observation, 5-bromo-2-deoxyuridine (BrdU) incorporation and the terminal deoxynucleotidyl transferase mediated dUTP nick end labeling (TUNEL) technique. The results showed that the fat body cells divided continuously in the early larval stage from the 1st instar to the 3rd instar. Extensive apoptosis in the fat body could be detected only within a narrow time window during metamorphosis in the early pupal stage from prepupa to day 2 pupa. During metamorphosis, the fat body of larva degenerated and reorganized to form the adult fat body. This study provides a theoretical basis for research on the function of fat body and the mechanisms of autophagy and apoptosis.

Key words:  Apis mellifera ligustica, fat body, immunohistochemistry, proliferation, apoptosis, 5-bromo-2-deoxyuridine (BrdU), terminal deoxynucleotidyl transferase mediated dUTP nick end labeling (TUNEL)