Artificial insemination using trypsin-treated sperm in the silkworm, Bombyx mori

A new method was developed for artificial insemination of the silkworm. Vir gin females artificially inseminated by this method oviposited fertilized e ggs at a rate almost similar to that of females mated with males. Using ina ctive sperm collected from the seminal vesicles, we confirmed the previous finding by Omura, S., 1936a, Artificial insemination of Bombyx mori, Journa l of Faculty of Agriculture, Hokkaido Imperial University 38, 135-150, and Omura, S., 1938, Studies of the reproductive system of the male of Bombyx m ori Il, Post-testicular organs and post-testicular behaviour of the spermat ozoa, Journal of Faculty of Agriculture, Hokkaido Imperial University 40, 1 29-170, that the sperm of B. mori requires the secretion of the glandula pr ostatica for activation. Sperm also could be activated by trypsin. At an op timal concentration, 0.3 mu g trypsin/ml in 50% semen solution, the fertili zation rate as well as the number of eggs oviposited was almost equivalent to that obtained in normally mated moths. These results may contribute not only to basic studies on fertilization and reproduction in Lepidoptera but also to the development of long-term preservation of genetic resources by u sing cryopreserved sperm of B. mori and other Lepidoptera insects. (C) 1999 Elsevier Science Ltd. All rights reserved.