Sericulture | Zoology Optional Notes for UPSC PDF Download

Definition of Sericulture

Sericulture is the intricate process involving the breeding, cultivation, and management of silkworms to produce high-quality raw silk. Various species of silkworms, such as Mulberry silkworm, Eri silkworm, and Giant silkworm, contribute to silk production. The primary agent responsible for silk production is the silkworm, an insect known for its remarkable silk-spinning capability.

History of Silk

The origins of silk production can be traced back to China, where silk served not only as a fabric for clothing but also found applications in diverse fields. The color of silkworms held significance in determining social classes during the Tang Dynasty. Beyond China, the Arab world also ventured into silk manufacturing. Despite efforts by several nations in the 16th century, only France and Italy achieved success in establishing a thriving silk trade, diminishing the dominance of Chinese silk exports.

Process of Sericulture

The sericulture process involves two main stages:

1. Rearing of Silkworm:

• Silkworm farmers acquire eggs and create suitable conditions for hatching.
• Caterpillars grow by feeding on Mulberry leaves in controlled environments.
• Caterpillars are placed in clean bamboo trays with Mulberry leaves, and they move to a chamber to build cocoons.
• Small drags are provided for cocoon attachment, and the silkworm spins the cocoon inside.

2. Processing Silk:

• Once cocoons are obtained, they are either boiled or subjected to heat to facilitate the separation of silk fibers.
• The silk fibers are drawn, rolled into threads, and further processed for various applications.

Taxonomic Position of Silkworm

• Phylum: Arthropoda (jointed)
• Subclass: Pterygoid (have wings)
• Division: Endopterygota (undergo distinctive larval, pupal, and adult stages)
• Order: Lepidoptera (four large covered wings, distinctive markings, and caterpillar larvae)
• Superfamily: Bombycoidae
• Species: Mori

Species of Sericulture

More than 500 species of wild silkworms exist globally, with two main species used for clothing production:

1. Bombycidae (Bombyx Mori):

• Popularly known as the Chinese silkworm or Mulberry silk moth.
• Buff-colored caterpillars, approximately 4 centimeters long, with brown lines on their bodies.
• Native to China and famous for silk production in Japan, India, Korea, Italy, etc.
• Feeds exclusively on Mulberry leaves, earning the name "Veracruz feeder."
• Bombyx Mori encompasses several races and varieties.

2. Life Cycle of Bombyx Mori

• Separate sexes in silk moths with complicated metamorphosis.
• Female moths lay 400 to 500 eggs on Mulberry tree leaves.
• Eggs hatch into caterpillar larvae, which go through multiple molts.
• Full-grown larva, about 800 centimeters long, forms a cocoon by secreting silk through spinnerets.
• Cocoon formation takes 2-3 days, providing a protective covering for the pupa.

3. Eri Silkworm:

• Mainly reared on the castor plant (Samia Cynthia Ricini).
• Produces silk that can be white or brick red.
• Polyphagous, feeding on various plants.
• Cocoon is not continuous, allowing for the emergence of the moth.

In North India, regions like Brahmaputra, Meghalaya, Mizoram, Nagaland, Manipur, and Arunachal Pradesh are renowned for Eri silkworm cultivation.