Development a long-term storage method for diapause eggs in some hybrid races of Bombyx mori

Abstract

Maintaining silkworm races can probe to be labor intensive because stock races must be reared annually. The most effective way of reducing labor is to extend the period of preservation. A method for rearing silkworms bi-annually was recently proposed; however, it required several complicated procedures for egg preservation. In this study, we developed a simpler method for the preservation of silkworm diapause eggs, involving minimum care, refrigeration, and without terminating diapause. We first optimized storage conditions by investigating the relationship between the long-term storage of diapause eggs and the number of days needed to achieve diapause at 25°C, as well as the number of days required for termination at 5°C. We then developed a very simple 2-year egg storage method, using a high-humidity refrigerator for egg storage and only one intermediate care procedure. Using this new method, the period from one generation to the next is now 2years.