Abstract: 【Aim】 The process of the growth and differentiation of wing discs of the silkworm, Bombyx mori is accompanied with the disappearance of such tissues as hematopoietic organs and wing bursa. The study aims to analyze whether apoptosis and autophagy occur during the growth and differentiation of wing discs in the silkworm. 【Methods】 Apoptosis in wing discs of B. mori at the pupal stage was analyzed by TUNEL. The total RNA of wing discs at day-3 and day-6 5th instar larval stage, day-1 wandering stage, pre-pupal stage, and day-0 and day-3 pupal stage were extracted and then reversely transcribed into cDNA. The expression patterns of apoptosis and autophagy related genes were detected by qRT-PCR. The activities of Caspase 3 and acid phosphatase were analyzed. 【Results】 It was observed that apoptosis occurs in the partial wing discs cells at day-0 pupal stage. The apoptosis related genes Caspase 3 and Nc had higher expression levels during the 5th instar larval stage, while IAP had higher expression level at the late larval stage than at the pupal stage. The activity of Caspase 3 reached the peak at day-1 wandering stage. The autophagy related genes Atg5, Atg6, Atg8 and Atg12 had higher expression levels during the late larval stage. The acid phosphatase activity was higher during the late larval stage. 【Conclusion】 Apoptosis might occur during the larval stage to inhibit the cell proliferation of wing discs and to prevent wing discs from growth and differentiation. Apoptosis and autophagy might occur at the late larval stage to promote the degeneration of wing bursa, to inhibit the cell proliferation of wing discs, and to push forward the development of pupal wing from wing discs.

Key words: Bombyx mori, wing disc, apoptosis, autophagy, Caspase 3, acid phosphatase