The incredible material we know as silk is produced not by the adult silk moth, but by its larval stage, the silkworm (Bombyx mori). This process is a vital part of the silkworm's life cycle, creating a protective casing for its metamorphosis.
Concise Answer: Silkworms produce silk by releasing a fluid called fibroin that hardens into a single, long filament upon exposure to air, and then they intricately spin this filament into a cocoon by rotating their body.
The Silkworm's Silk Production Explained
The production of silk is a remarkable biological process carried out by the silkworm before it enters its pupal stage.
The Science Behind Silk Creation
The silkworm possesses specialized glands that synthesize and store the silk proteins. The primary protein making up the silk filament is fibroin.
- Step 1: Fibroin Secretion: The silkworm extrudes a liquid form of fibroin through openings called spinnerets located near its mouth.
- Step 2: Hardening in Air: As the secreted fibroin comes into contact with the surrounding air, it undergoes a chemical change and rapidly hardens into a solid thread (Agricultural Holdings International 2018).
- Step 3: Filament Formation: This hardening process creates a continuous, singular filament. This filament is exceptionally long, typically measuring 1,000 to 3,000 feet (Agricultural Holdings International 2018).
- Step 4: Cocoon Spinning: The silkworm then uses this filament to construct its cocoon. It does this by systematically moving and rotating its body. This spinning action is extensive; a silkworm will rotate its body up to 300,000 times over the course of several days to complete its cocoon (Agricultural Holdings International 2018).
This intricate process results in the dense, protective silk cocoon from which raw silk fiber is obtained.
Key Facts About Silkworm Silk
Based on the process described:
- The raw material released is a fluid protein called fibroin.
- Air exposure causes the fibroin to harden into a solid thread.
- A single thread from one cocoon can be over 1,000 feet long.
- The silkworm performs intense body rotation to spin the cocoon.
The silk thread created serves as the foundation for the global silk industry, valued for its strength, luster, and softness.
