UTTAR PRADESH JOURNAL OF ZOOLOGY

The present study investigates the rearing performance of the mulberry silkworm, Bombyx mori (bivoltine C004 breed), in two distinct agro-climatic zones (Sanjenbam Hill and Wangkhei) of Manipur during the spring season (March-April) 2025. A comparative study was conducted between two different zones (hill and valley) in Manipur to evaluate the influence of regional environmental factors on the growth, development, and cocoon yield of silkworms as there is limited research on the suitability of bivoltine strains for high-altitude conditions. Key parameters such as fecundity, hatchability, larval duration, larval weight, cocoon weight, pupal weight, shell weight, shell ratio, effective rate of rearing, eclosion, silk productivity, filament length, denier, renditta and cocoon yield were recorded. The rearing house of Wangkhei, with a temperature range of 15⁰C -29.5⁰C and 38%- 91.50% relative humidity range, exhibited shorter larval duration (26±0.577 days), while the rearing house of Sanjenbam hill, with a temperature range of 10.49⁰C - 26⁰C and a 22.46%- 99.21% humidity range, showed longer larval duration (30±0.578 days). Fecundity, hatchability, weight of ten mature larvae, cocoon weight, pupal weight, shell weight, shell ratio, eclosion, silk productivity, filament length and cocoon yield (by weight) were recorded higher in the Wangkhei zone, whereas survival rate, effective rate of rearing, denier, renditta and cocoon yield (by number) were recorded higher in Sanjenbam hill. The findings highlight the role of different environmental conditions in sericultural productivity and emphasise the need for location-specific strategies to optimise silkworm rearing outcomes.