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Mulberry silk is considered one of the most expensive types of natural silk. It’s a domesticated species of silk and accounts for around 90% of global silk production. Since the silkworms of the Bombyx mori moth are fed only mulberry leaves, the resulting silk is one of the best available in the world. Mulberry silk, with its pure white colour and individual long fibres, is more refined than other type of silk. Mulberry saplings are planted in nurseries and take about 6 months to grow. The leaves of the mulberry trees are then harvested to be fed to the silk larvae.
Lifecycle of the Silkworm
Silkworm has four stages in its lifecycle; egg, silkworm, pupa and moth. The life cycle of a silk moth starts when the female silk moth lays eggs. The caterpillar or larvae hatch from the eggs. These caterpillars now feed on mulberry leaves and grow in size. In the pupa stage, the worm spins a fibre made up of a protein secretion to form a cocoon. In the last stage, the pupa pierces one end of the cocoon to emerge as a beautiful fully grown moth.
Stage 1: Eggs
An egg is the first stage of the life cycle of a silkworm. The process starts with rearing the silkworm, Bombyx mori, in a controlled environment. The female silkworm lays eggs, which are the size of small dots and are incubated for a few days until the eggs hatch into larvae. The eggs hatch within 25 days, depending on the weather. They are now ready to be fed mulberry leaves.
Stage 2: Silkworms
The larvae are fed huge quantities of chopped mulberry leaves for about 6 weeks. During this time, they shed their skin 4 times and grow to about 4 inches long. Care has to be taken to feed them twice a day, ensuring they do not run out of leaves. This is the most crucial stage in silkworm rearing and one of the deciding factors in the success of the cocoon crop. Optimal temperature and high humidity have to be maintained. Containers have to be placed away from predators such as ants and other insects.
Stage 3: Pupa
After 20-23 days, the silkworms stop eating and are now ready to spin the cocoon. At this stage, they become translucent. Now, the worms are attached to a frame, where they rotate their bodies continuously, secreting saliva. The saliva hardens in contact with air, forming a pair of silk filaments. They also secrete a gummy fluid, sericin, which binds the filaments together for protection. Over the next 4 days, the silkworm spins about 1 km of filament, constructing a cocoon and encloses itself completely within it, growing into a pupa. From every batch of cocoons, a small portion of the male and female pupae are kept aside, until they grow into moths and are mated for producing the next generation of silkworms. The remaining cocoons are sent for processing into silk.
Stage 4: Moth
After 10-14 days of developing inside the Chrysalis, the silk moth then emerges from the cocoon. These do not fly, due to thousands of years of domestication. The male silk moths move around in search of females to complete the process of mating. It is easy to detect the difference between male and female silk moths, due to the slightly large abdomen of the females. The males also tend to be more active. The average life of a silk moth is about 5-10 days. After mating, the females lays around 300-500 eggs before dying, while the males continue to search for another mate.
Is it Non-violent? Both Ahimsa and Non-ahimsa mulberry silk are produced commercially. Ahimsa mulberry is produced by allowing the moths to hatch from the cocoons before harvesting. Therefore, ahimsa mulberry is a spun silk, not a filament, making it very different in texture and lustre from regular silk.
Non-ahimsa mulberry, which represents almost the entire global production and is usually made at a very large, commercial scale, is produced by boiling cocoons with the larva still inside. Single, continues filaments are pulled off the cocoon to create very long fibres. A few of these fibres are twisted together and woven to create highly lustrous silk.
At aeshaane, we use the ahimsa mulberry silk cocoons to make Upcyled cocoon necklaces.