High temperature environment at the spinning stage and sterilization in the males of the silkworm, Bombyx mori

• Published in: The Journal of Sericultural Science of Japan Vol. 50; no. 1; pp. 65 - 69
• Main Authors: SUGAI, Etsuji, TAKAHASHI, Takahiro
• Format: Journal Article
• Language: English; Japanese
• Published: The Japanese Society of Sericultural Science 1981
• ISSN: 0037-2455; 1884-796X
• DOI: 10.11416/kontyushigen1930.50.65

The sterility in the males of the silkworm, Bombyx mori, induced by high temperature (32°C or 33°C) was investigated paying a particular consideration to the thermoperiodism and anatomical and cytological evidences for the sterility. Results are summarized as follows: 1. When males were kept at the high temperature within 36hrs after the initiation of spinning, no sterilization was obtained. However, the rate of sterilization increased rapidly by treating after 48-54hrs, and the most males were sterilized when kept at 32°C for 72hrs, or more after the start of spinning. 2. Effect of periodical daily changes of the temperature (32°C:25°C, 32°C:20°C, and 32°C:16°C) on the male sterilization was examined. Pronounced sterilization occurred when high temperature treatment beyond 19hrs in a day was applied. 3. A large amount of eupyrene sperms was ejaculated into the bursa copulatrix of the female moth copulated with the sterilized male moth, whereas the amount of apyrene ones was markedly reduced. Furthermore, neither eupyrene nor apyrene sperm was found in the receptaculum seminis. 4. By histological observations of spermatogenesis after high temperature treatment, marked abnormalities were observed in the formation process of apyrene sperms, and many of them were remained in the testicular chamber without penetrating the basement membrane. From these observations, we presumed that the male sterilization may be ascribed to the abnormality of apyrene sperms.