Sericulture

Another economically important insect is the silkworm. We get fibers of silk from the secretions of the silkworm. The breeding and management of silkworms for the commercial production of silk is called sericulture. Sericulture is an important industry in Japan, China, India, Italy, France, and Spain. There are four types of natural silk, which are commercially known and produced in the world. Among them, Mulberry Silk is the most important and is alone constitutes the 90% world Silk production. Therefore, the term silk, in general, refers to the silk of the mulberry silkworm (Bombyx Mori). Bombyx Mori is the only living species of the family Bombycidae domesticated by man. The other three commercially important types of non-mulberry silk are Tassar silk, Moga silk, and Eri silk. The Tasar silkworms belong to the genus Antheria royeli. The larvae of this genus are reared in the wild mostly on Arjuna trees. The Muga silkworms belong to the genus Antherea assama. The larvae of this genus are read on Som trees found only in the state of Assam. The Eri silk is produced by the moth Philosamia ricini. The larvae feed on Castor leaves.

Sericulture is an agro-based industry. It has played a vital role in the improvement of the rural economy.

Life history of Silk Moth

The total life span of the Silk Moth is about 50 days. There are various stages in the life history of the silk moth. The life history begins with the hatching of eggs into young caterpillars or larvae which then grow into pupa or chrysalis. And then finally transforms into adult Moths. An adult female moth lays 300-500 eggs on the leaves of the mulberry tree. The eggs are round and yellowish-white in colour but turn grey around the time of hatching. The newly hatched larvae is about 3 mm long and somewhat black in colour. The larvae feed on the Mulberry leaves and grow in size. The Larvae shed their skin four times periodically in a process called molting. After the fourth molting, the mature larva stops feeding and rests on a twig. The larva possesses two large silk glands that are modified the salivary glands. These glands secrete a clear viscous fluid which on exposure to air gets hardened and form a fine Silk fiber, and thus a cocoon is fun around the body of the Larvae. The filament forming a cocoon is continuous and may measure from 700 to 1100 meters in length. The full-grown larvae then pupate inside the cocoon. In about 10 days the pupae develop into a winged adult. This adult moth secretes a substance and dissolves one end of the cocoon. It now escapes out through the opening in the cocoon. The adult silk moth is creamy white in colour and has a flat body with small wings. It lives for only 2-3 days.