THE PHYSIOLOGY OF INSECT DIAPAUSE. VI. EFFECTS OF TEMPERATURE, OXYGEN TENSION, AND METABOLIC INHIBITORS ON IN VITRO SPERMATOGENESIS IN THE CECROPIA SILKWORM

Abstract

1. The effects of temperature, metabolic inhibitors, oxygen tension, and carbon monoxide were studied in relation to the in vitro spermatogenesis (meiosis and spermiogenesis) of the male sex cells of the Cecropia silkworm. 2. A method is described for the quantitative study of the rate of spermatogenesis. 3. The optimum temperature for spermatogenesis is 25° to 30° C. 4. An appraisal of the effects of twenty diverse metabolic inhibitors revealed that the glycolytic system mobilizes substrates for spermatogenesis, that the tricarboxylic acid cycle is apparently the main pathway of acetate utilization, and that oxidative phosphorylation energizes spermatogenesis. 5. Spermatogenesis is shown to be an aerobic process, the terminal oxidase mediating the respiration being saturated by oxygen at tensions lower than 8 mm. of Hg. 6. Spermatogenesis is blocked or retarded by several inhibitors of the cytochrome system; the inhibition by carbon monoxide is light-reversible. 7. The findings on the isolated sex cells are compared to the effects of the same series of agents on the intact insect. The biochemical systems responsible for the meiosis and differentiation of spermatocytes in vitro are apparently the same as those which serve the development of the insect as a whole.