Silk
Silk moths lay eggs on specially prepared paper. The eggs hatch and the caterpillars (silkworms) are fed fresh mulberry leaves. After about 35 days and 4 moltings, the caterpillars are 10,000 times heavier than when hatched and are ready to begin spinning a cocoon. A straw frame is placed over the tray of caterpillars, and each caterpillar begins spinning a cocoon by moving its head in a pattern. Two glands produce liquid silk and force it through openings in the head called spinnerets. Liquid silk is coated in sericin, a water-soluble protective gum, and solidifies on contact with the air. Within 2–3 days, the caterpillar spins about 1 mile of filament and is completely encased in a cocoon. The silk farmers then heat the cocoons to kill them, leaving some to metamorphose into moths to breed the next generation of caterpillars. Harvested cocoons are then soaked in boiling water to soften the sericin holding the silk fibers together in a cocoon shape. The fibers are then unwound to produce a continuous thread. Since a single thread is too fine and fragile for commercial use, anywhere from three to ten strands are spun together to form a single thread of silk.
Commercial butterfly breeding
Commercial breeding of Lepidoptera has a long history. The "Bombyx mori" (Latin: "silkworm of the mulberry tree"), The practice of breeding silkworms for the production of raw silk, also known as Sericulture, has been underway for at least 5,000 years in China. It is dependent on humans for its reproduction and does not occur naturally in the wild. The silkworm was domesticated from the wild silkmoth "Bombyx mandarina" which ranges from northern India to northern China, Korea, Japan, and the far eastern regions of Russia. The domesticated silkworm derives from Chinese rather than Japanese or Korean stock. Silkworms were unlikely to have been domestically bred before the Neolithic age; before then, the tools required to facilitate the manufacturing of larger quantities of silk thread had not been developed. The domesticated "B. mori" and the wild "B. mandarina" can still breed and sometimes produce hybrids...