[Impact of high temperature on testicular growth and development of valuable silkworm Antheraea yamamai(Lepidoptera: Saturiidae)].

The results indicated that high temperature had a significant impact on the growth and development of testis in Japanese oak silkworm Antheraea yamamai. The testicular size of the 3rd and 4th instar larvae increased within the range from 20 to 29 degrees C, and slightly decreased at 32 degrees C. While in the 5th instar, it decreased within the range from 20 to 26 degrees C, with the biggest size at 20 degrees C. The testis was almost hard to grow and develop because the larvae could not survive at 29 to 32 degrees C. When the mature larvae were treated at 32 degrees C at the beginning of coconing or at the 1st or 6th day of pupating, the growth of testicular size and spermatogenesis were significantly arrested, and the sperm number and the content of soluble protein in the testis markedly decreased. When the male moth of the 1st day was treated at 32 degrees C, the activity of the sperms in the testis obviously decreased, in contrast to the treatment at 20 degrees C. It is concluded that for the egg raising of the silkworm, its mature larvae, puape in cocoons and male moths should not be exposed to 32 degrees C from cocooning to adult stage. The proper temperature for rearing 3rd, 4th and 5th instar larvae was discussed.