WHAT IS SILK :
Man is always inquisitive for silk products. SILK - The Queen of Textiles,
spells luxury, elegance, class and comfort. Mankind has always loved this
shimmering fibre of unparalleled grandeur from the moment Chinese Empress
Shiling Ti discovered it in her tea cup. It withstood many a daunting
challenges from other natural and artificial fibers and yet, remained
the undisputed Queen of Textiles since centuries. Exquisite qualities
like the natural sheen, inherent affinity for dyes and vibrant colours,
high absorbance, light weight, resilience and excellent drape etc. have
made silk, the irresistible and inevitable companion of the eve, all over
the world.
Chemically speaking, silk is made of proteins secreted in the fluid state
by a caterpillar, popularly known as 'silkworm'. These silkworms feed
on the selected food plants and spin cocoons as a 'protective shell' to
perpetuate the life. Silkworm has four stages in its life cycle viz.,
egg, caterpillar, pupa and moth. Man interferes this life cycle at the
cocoon stage to obtain the silk, a continuous filament of commercial importance,
used in weaving of the dream fabric.
ORIGIN OF SILK:
According to Chinese legend, the culture and use of Silk originates
4000 years back on the banks of Hwang-ho or Yellow River. The empress
Si-Ling-Chi learned how to rear the caterpillars on mulberry leaves
and how to unwind the silk from cocoons. The secret of silk-making was
kept close by the Chinese and was smuggled into Japan early in the Christian
era and also reached India. Raw Silk is now extensively produced in
China, India, Vietnam, Russia and Japan.
SERICULTURE:
Silk is a strong, soft, lustrous fibre extruded by certain kinds of
moth and spiders. The cultivated silk variety is produced by the species
Bombyx mori. There are other less-cultivated species, known as Wild
Silk (such as Tussar feeding on Oak leaves, Eri on Castor-oil plant
leaves and Muga on variety of polyanthus leaves like Som, soalu etc.).
Silkworm eggs (popularly known as seeds) are laid out on the mulberry
leaves to hatch out into caterpillars about 2 mm long.
They grow rapidly, eat voraciously and end up about 30 mm long after
4-5 weeks. During this time, they change skins 4 times. After final
skin change, straw frames are provided in which silkworms makes its
cocoon. Cocoon-making takes further 8 days, It takes the silkworm another
3-4 days to transform into pupa and another 15 days for the moth to
emerge. Like all other moths, the insect passes through four stages
in it's life : Egg, Caterpillar, Pupa (or chrysalis) and perfect insect.
Female moth lays 200-500 eggs at a time, normally in the summer. Twin
silk threads (fibroin- in fluid form) are extruded through two glands
together with a gummy substance -sericin, which binds the filaments
together as well as forms the walls of cocoon. By moving its head from
side to side, the silkworm lays the filament in a series of figure `8'
gradually building from wall to wall.
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