Effect of Light and Dark Exposure on the Different life Parameters of Silk Worm, Bombyx Mori l. (Bombycidae: Lepidoptera)

The performance of the Japanese race of silkworm, Bombyx mori L. (Bombycidae: Lepidoptera) was studied at Sericulture Wing, Forest Department Peshawar under laboratory conditions of 25 + 2 °C temperature and 70+10 % relative humidity in complete dark (24 hours) and a complete light (24 hours) condition. The results showed that mean life cycle of B. mori was 62 days in dark and 68 days in light. The diurnal variation in the activity persisted in constant darkness, but was suppressed by constant light. Mean cocoon weight was 1.06 gm in dark and 0.9 gm in light. Mean shell weight in dark and light was 0.2 gm and 0.16 gm, respectively. Shell ratio in dark was 19.40 gm, whereas it was 18.35 gm in light. Percentage of sex ratio (F:M) was 56:44 in dark, whereas it was 42:58 in light. Mortality percent of larvae kept in dark was lower (13.3 %) than in light (24.4 %). Mean fecundity of the adults emerged from larvae kept in dark and light was 112.6 and 46.7 eggs/f, respectively. Generally, that the duration of life cycle, cocoon weight, shell weight, percent shell ratio, percent sex ratio, percent mortality, and fecundity of the larvae reared in dark was significantly better than the larvae kept in light condition