Effect of Cold Storage of Female Pupae of Silkworm Bombyx Mori L. on Survival and Reproductive Behaviours

Abstract

Present study was an attempt to investigate the effect on survival and reproductive behaviors of two multivoltine breeds of silkworm, Bombyx mori (L), istari and M. Con. 4 under cold storage at 10+2*rC for 2, 4, 6, 8 and 10 days on 8th day of spinning in order to synchronize the emergence of female and male moths of required combination for mating. The female pupae had an adverse effect on its survival with the increased days of cold storage. Female moths emerged from cold treated pupae of both multivoltine breeds showed 100% pairing efficiency with fresh males of NB4D2, a pure bivoltine breed and (SK6 x SK7), (BHR2 x BHR3)-the newly evolved bivoltine foundation cross breeds. On the other hand, pair to Laying percentage decreased progre sively with the increased duration of cold treatment. In treated batches pair to laying, percentage decreased maximum after 10 days of cold treatment in case of istari x NB4D2 (33. 42%), whereas it was 65. 49 and 64. 39 % in case of [ istari x (SK6 x SK7)] and [ istari x (BHR2 x BHR3)] respectively. However, it was 92. 45, 95. 14 and 94. 23% respectively in control. Similarly, in M. Con. 4 x NB4D2, [M. Con. 4 x (SK6 x SK7)] and [M. Con. 4 x (BHR2 x BHR3)] after 10 days of cold treatment, the pair to laying percentage was 75. 79, 82. 23 and 79. 58% against control which was 96. 00, 95. 74 and 96. 71% respectively. Similar trend of significant (P<0. 05) results were observed in recovery and hatching percentage of laying's in cold treated batches of all the combinations when it was compared among the treatments and combinations.