Sterilizing Effect of High Temperature on the Male Silkworm, Bombyx mori L. : Lepidoptera : Bombycidae

Abstract

Sterility of the male silkworm, Bombyx mori induced by high temperature (32°C)was investigated in relation to their developmental stages. The sterilizing effect of high temperature was the strongest at the prepupal stage, from spining to pupation, and followed by the pupal period, whereas no sterilizing effect was obtained in the fifth larval instar. In the treatment with cyclic changes of high (32°C) and moderate(23°C) temperatures for 8 days from spining to early pupae, no sterilization occurred when the treatment was given at 12 hr intervals, but the starility markedly increased if the time intervals were extended to 24 hr. Furthermore, a relationship between male sterilization and developmental stages of the insect was discussed, paying a particular consideration on the development of their germ cells.