STUDIES ON THE OCCURRENCE OF DOUBLE COCOONS IN TWO RACES OF SILKWORM BOMBYX MORI L

摘要

In two elite bivoltine races viz. CSR2 and CSR4 of Silkworm, Bombyx mori, L the percentage of the combination of male-female, female-female and male-male pupae were 46.952, 32.125,14.497 and 43.198,25.536 and 20.525 respectively in double cocoons. Theorientation pattern of the pupae i.e. the anterior end in opposite direction was observed to be on the higher side (74.034 and 85.635) in male-female combination of CSR2 and CSR4 respectively rather than anterior end in the same direction; while the anterior end in the same direction was found more in the female -female and male -male combination in both the races. It was also observed that the involvement of the females in the formation of double cocoons was more in both the races. The probable reasons of such differences and alignment in the population have been discussed,