BASIS OF THE PREDOMINANCE OF MALE-FEMALE ASSOCIATION IN THE DOUBLE COCOONS OF SILKWORM, BOMBYX MORI L.

Abstract

Double cocoons of silkworm Bombyx mori (NB4D2 x KA and PM X NB4D2) were collected and the pupal sexassociation was examined. Male-female pupal association occurred more frequently than male-male and femalefemalein double cocoons formed in normal populations of silkworm larvae. The percentage occurrence of male-male,male-female and female-female association was 26.8, 51.2 and 22.0 respectively in NB4D2 XKA and 27.2, 50.0 and22.8 respectively in PMX NB4D2. The overall participation of male larvae in double cocoon formation was found morethan that of females. When male and female larvae were made to spin separately, the double cocoons formed hadeither male-male association or female-female association depending on the treatment. This study, for the first timeproves that the predominance of male-female sex association in the double cocoons is not due to any affinitybetween the opposite sexes but only due to the random encounter of male and female larvae during spinnin