Breed-Specific Growth and Development of Bombyx mori L. under Temperature and Humidity Stress
Vaibhav Annasaheb Late *
Department of Zoology, Dr Babasaheb Ambedkar Marathwada University, Chhatrapati Sambhajinagar (MS), India and Department of Zoology, Jijamata College of Science and Arts, Bhende (Bk), Tal. Newasa, Dist. Ahilyanagar (MS), India.
Rajashri Deolalikar
Paul Hebert Centre for DNA Barcoding and Biodiversity Studies, Dr Babasaheb Ambedkar Marathwada University, Chhatrapati Sambhajinagar (MS), India.
Amol Kalyankar
Paul Hebert Centre for DNA Barcoding and Biodiversity Studies, Dr Babasaheb Ambedkar Marathwada University, Chhatrapati Sambhajinagar (MS), India.
*Author to whom correspondence should be addressed.
Abstract
Heat stress is one of the major environmental challenges effects on the growth, survival, and silk productivity of Bombyx mori, the most economically important insect in sericulture. With rising global temperatures, the identification of thermotolerant silkworm breeds has become important for supporting silk production. While several studies have addressed thermal effects on silkworm physiology, limited research exists on evaluation of multiple bivoltine breeds under uniform controlled conditions, creating a critical gap in understanding breed-specific thermotolerance. In this study, bivoltine silkworm breeds were reared as control (26 ± 1 °C, 85 ± 5% RH) and high-temperature (34 ± 1 °C, 50 ± 5% RH) conditions to evaluate key quantitative traits including fecundity, survival rate, cocoon weight, shell ratio, and filament length. Data were statistically analyzed using ANOVA, coefficient of variation (CV%), and critical difference (CD) tests to determine the significance of inter-breed variation. Results show highly significant differences among breeds under heat stress. Breeds such as APDR105, APS45, and AC9 maintained higher survival, better cocoon weight, and longer filament length, whereas APS9 exhibited acute sensitivity, with drastic reduction in survival and complete cocoon failure. Elevated CV% values under heat stress indicated enhanced phenotypic variability across traits. The outcomes demonstrate that certain breeds possess inherent thermotolerant mechanisms, making them potential candidates for selective breeding programs targeting climate resistance. The study not only bridges the gap in identifying robust thermotolerant genotypes but also provides a foundation for breeding strategies to safeguard sustainable sericulture in heat-prone regions.
Keywords: Bombyx mori, thermal stress, fecundity, survival rate, cocoon weight, filament length