Implications of Temperature and Humidity on the Moulting Patterns and Moulting Survival in the Silkworm, Bombyx mori L.

The implications of temperature and relative humidity on the moulting pattern, moulting duration and moulting survival were studied in the silkworm, Bombyx mori L. Larvae of two pure silkworm breeds, Pure Mysore (PM) and NBDand their hybrid, were reared under experimental conditions under natural day photoperiodic (LD 12:12) condition. Two developmental marker events in the fourth moulting, settling for moult (SM) and completion of moult (CM) occurred at or around the middle of the photophase. The computed mean vector (equation omitted), based on the circular statistics also confirmed the above. Temperature and humidity did not alter the moulting rhythmicity much. However, extreme temperature and humidity conditions reduced moulting survival in PM and . Further, moulting survival reduced below the economic level in . The temperature and humidity together seem to exert synergic impact on the moulting survival of the silkworm Bombyx mori, at least in .