Seasonal variation in the growth and development of Indian Tasar Silk worm Antheraea mylitta Drury

Abstract

Silk worm has four stages (Fig.1.1) in its life cycle viz., egg, caterpillar, pupa and moth. Silk is a fine protein fibre produced by the silk worm from the silk gland at the end of its larval period to form a protective covering around its body called as cocoon. The larva remains inside the cocoon and metamorphoses into a pupa. The pupal stage is the dormant stage demanding protection. The cocoon helps the inside animal to overcome the unfavourable environmental conditions and to get protection from natural enemies. The pupa rests inside the cocoon and at the approach of favourable conditions it emerges out as the adult form of the silk moth by piercing through the cocoon. newlineSilk filament is basically a glycoprotein containing two components of protein namely fibroin and sericine along with some carbohydrate and some other minor constituents. Inner filament is known as fibroin and the outer filament is known sericine. The fibroin is secreted by the silk gland and the sericine is secreted from the stomach. Silk fibres are collected by reeling or spinning of the cocoon through suitable techniques to form a composite thread fit for weaving of silk fabrics. The real importance of silk lies in its usefulness as the leading fashion fabric in handloom textile industries throughout the world. The physical appearance, physiological properties, versatile use, hygienic and aesthetic values make the silk a highly priced material all over the world. newline newline