Wild silks have been known and used in many countries from early times, although the scale of production is far smaller than that from cultivated silkworms. Silk cocoons and nests often resemble paper or cloth, and their use has arisen independently in many societies. [1]
Silk taken from various species has been used since ancient times, either in its natural state or after some form of preparation. Spider webs were used as a wound dressing in ancient Greece and Rome, [2] and as a base for painting from the 16th century. [3] Caterpillar nests were used to make containers and fabric in the Aztec Empire. [1] [4]
To make a woven fabric, silk threads must first be either carded and spun, or extracted as a single intact thread. Commercially reared silkworms of the species Bombyx mori (Linnaeus, 1758) are normally killed before the pupae emerge, either by pricking them with a needle or dipping the cocoons into boiling water, thus allowing the whole cocoon to be unravelled as one continuous thread. This allows a much finer cloth to be woven from the silk.
There are more than 500 species of wild silkworms in the world, although only a few (nearly all listed below) are used to produce cloth. They usually produce a tougher and rougher silk than that from domesticated B. mori. Wild silks are usually harvested after the moths have left the cocoons, cutting the threads in the process, so that there is not one long thread, as with domesticated silkworms.
Wild silks are more difficult to bleach and dye than silk from Bombyx mori, but most have naturally attractive colours, particularly the rich golden sheen of the silk produced by the muga silkworm from Assam, often known as Assam silk.
The cocoon shells of wild silk moths are toughened or stabilized either by tanning (cross-linking) or by mineral reinforcements (e.g. calcium oxalate). [5] In 2011, a new method was developed for demineralizing silk, which can remove the mineral reinforcements present in wild silks and enables wet reeling like the commercial silkworm. [6] [7]
Wild silks are often referred to in India as 'Vanya' silks:
The term 'Vanya' is of Sanskrit origin, meaning untamed, wild, or forest-based. Muga, Tasar, and Eri silkworms are not fully tamed and the world calls the silks they produce as 'wild silks'. [8]
India produces four kinds of silk: mulberry, tasar, muga and eri. The silkworm Bombyx mori is fed on mulberry leaves cultivated in plantations. Silkworms are also found wild on forest trees, e.g Antheraea paphia which produces the tasar silk (Tussah). Antheraea paphia feeds on several trees such as Anogeissus latifolia , Terminalia tomentosa , T. arjuna ( Terminalia arjuna ), Lagerstroemia parviflora and Madhuca indica . Antheraea assamensis produces muga silk, and another wild silkworm ( Samia ricini ) produces eri silk. The estimated annual production of tasar silk is 130 tonnes. Production of other types of silk exceeds 10 000 tonnes (Gupta 1994). [9]
In 2015, the complete sequence and the protein structure of Muga Silk Fibroin was analyzed and published. [10]
The eri silk worm from India feeds on the leaves of the castor plant. It is the only completely domesticated silkworm other than Bombyx mori. The silk is extremely durable, but cannot be easily reeled off the cocoon and is thus spun like cotton or wool. [11]
Some of the best quality wild silk is produced by silkworms in Henan. This is the only type of wild silk that can be easily dyed. [12] [ unreliable source? ]
Wild silk threads have been found and identified from two Indus River sites, Harappa and Chanhu-daro, dating to c. 2450–2000 BCE. This is roughly the same period as the earliest evidence of silk use in China, which is generally thought to have had the oldest silk industry in the world. The specimens of threads from Harappa appear on scanning electron microscope analysis to be from two different species of silk moth, Antheraea paphia and A. assamensis, while the silk from Chanhu-daro may be from a Philosamia species (eri silk), and this silk appears to have been reeled. [13]
Wild silks were in use in China from early times. Moreover, the Chinese were aware of their use in the Roman Empire and apparently imported goods made from them by the time of the Later Han Dynasty in the 1st to 3rd centuries CE. [14] [15]
There are significant indications in the literature that wild silks were in use in Persia and in Greece by the late 5th century BCE, apparently referred to as "Amorgina" or "Amorgian garments" in Greece. [16] Pliny the Elder, in the 1st century CE, obviously had some knowledge of how wild silkworms' cocoons were produced and utilised on the island of Kos for coa vestis , even though his account included some fanciful ideas.[ vague ] [17]
Wild silk was used and traded by the Aztecs, Mixtecs and Zapotecs at the time of Moctezuma (early 16th century CE). [18] [4] This silk came from the social caterpillars Euchiera socialis and Eutachyptera psidii, which produce communal silk nests that frequently reach 50 cm (20 inches) in length. [1] The nests were cut open and pasted together to make a paper-like fabric.
Whole nests have also been use as purses and containers for liquid, and sections of nest silk have served as bandages and as a base for painting.
Silk fibres from the same species have been extracted and spun to make sashes. This practice was recorded in Oaxaca in 1986, but had ceased by 1997. It is uncertain when the wild fibres were first used in this way; one hypothesis is that the techniques were learned from 16th-century colonists, who taught local people to grow imported Bombyx, and later adapted to the local wild silks. [19]
Large nests can be more than a meter long, but they average less than half that size ... most authors consider that G. psidii was the main source of silk in the commerce of the ancient Mexicans before and during the time of Moctezuma.
Aztec artisans cut up the large sacs, piecing together the resulting swatches into larger pieces of "fabric."
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Silk is a natural protein fiber, some forms of which can be woven into textiles. The protein fiber of silk is composed mainly of fibroin and is produced by certain insect larvae to form cocoons. The best-known silk is obtained from the cocoons of the larvae of the mulberry silkworm Bombyx mori reared in captivity (sericulture). The shimmering appearance of silk is due to the triangular prism-like structure of the silk fibre, which allows silk cloth to refract incoming light at different angles, thus producing different colors.
Bombyx mori, commonly known as the domestic silk moth, is a moth species belonging to the family Bombycidae. It is the closest relative of Bombyx mandarina, the wild silk moth. Silkworms are the larvae of silk moths. The silkworm is of particular economic value, being a primary producer of silk. The silkworm's preferred food are the leaves of white mulberry, though they may eat other species of mulberry, and even leaves of other plants like the osage orange. Domestic silk moths are entirely dependent on humans for reproduction, as a result of millennia of selective breeding. Wild silk moths, which are other species of Bombyx, are not as commercially viable in the production of silk.
Sericulture, or silk farming, is the cultivation of silkworms to produce silk. Although there are several commercial species of silkworms, the caterpillar of the domestic silkmoth is the most widely used and intensively studied silkworm. This species of silkmoth is no longer found in the wild as they have been modified through selective breeding, rendering most flightless and without defense against predators. Silk is believed to have first been produced in China as early as the Neolithic period. Sericulture has become an important cottage industry in countries such as Brazil, China, France, India, Italy, Japan, Korea, Russia, and Thailand. Today, China and India are the two main producers, with more than 60% of the world's annual production.
Bombyx is the genus of true silk moths or mulberry silk moths of the family Bombycidae, also known as silkworms, which are the larvae or caterpillars of silk moths. The genus was erected as a subgenus by Carl Linnaeus in his 10th edition of Systema Naturae (1758).
Samia cynthia, the ailanthus silkmoth, is a saturniid moth, used to produce silk fabric but not as domesticated as the silkworm, Bombyx mori. The moth has very large wings of 113–125 mm (4.4–4.9 in), with a quarter-moon shaped spot on both the upper and lower wings, whitish and yellow stripes and brown background. There are eyespots on the outer forewings. The species was first described by Dru Drury in 1773.
Fibroin is an insoluble protein present in silk produced by numerous insects, such as the larvae of Bombyx mori, and other moth genera such as Antheraea, Cricula, Samia and Gonometa. Silk in its raw state consists of two main proteins, sericin and fibroin, with a glue-like layer of sericin coating two singular filaments of fibroin called brins. Silk fibroin is considered a β-keratin related to proteins that form hair, skin, nails and connective tissues.
Assam silk denotes the three major types of indigenous wild silks produced in Assam—golden muga, white pat and warm eri silk. The Assam silk industry, now centered in Sualkuchi, is a labor-intensive industry.
Bombyx mandarina, the wild silk moth, is a species of moth in the family Bombycidae. It is the closest relative of Bombyx mori, the domesticated silk moth. The silkworm is the larva or caterpillar of a silk moth. Unlike the domesticated relative which is unable to fly or indeed persist outside human care, the wild silk moth is a fairly ordinary lepidopteran. Its main difference from the domesticated taxon is the more slender body with well-developed wings in males, and the dull greyish-brown colour.
Thai silk is produced from the cocoons of Thai silkworms. Thailand's silkworm farmers cultivate both types of the domesticated silkworms that produce commercial silk: Samia ricini, commonly known as the eri silkworm, which produces matte eri silk, and the Bombyx mori, producer of the better known, glossy mulberry silk. The latter is by far the larger silk producer of the two.
Eri silk is a type of peace silk produced by the domesticated silkworm Samia ricini. It is primarily produced in the northeastern Indian states of Assam, Nagaland and Meghalaya, but it is also found in Bihar, Odisha, West Bengal and Andhra Pradesh on a smaller scale. It was imported to Thailand in 1974.
Antheraea assamensis, known as the muga silkworm as a larva and Assam silk moth as an adult, is a moth of the family Saturniidae. The species was first described by Johann Wilhelm Helfer in 1837. It is found in Assam in northeast India where 99% of its production occurs.
Tussar silk is produced from larvae of several species of silkworms belonging to the moth genus Antheraea, including A. assamensis, A. paphia, A. pernyi, A. roylei, and A. yamamai. These silkworms live in the wild forests in trees belonging to Terminalia species and Shorea robusta, as well as other food plants such as jamun and oak found in South Asia, eating the leaves of the trees on which they live. Tussar silk is valued for its rich texture and natural, deep-gold colour, and varieties are produced in many countries, including China, India, Japan, and Sri Lanka.
Antheraea pernyi, the Chinese oak tussar moth, Chinese tasar moth, or temperate tussar moth, is a large moth in the family Saturniidae. The species was first described by Félix Édouard Guérin-Méneville in 1855. Antheraea roylei is an extremely close relative, and the present species might actually have evolved from ancestral A. roylei by chromosome rearrangement.
Demineralizing has the potential to be used in the silk sector enabling wet reeling of Wild Silk moth cocoons by removing the mineral layer present in these cocoons. This technique is not like degumming where the gum of the fibroin fibres is removed what would lead to a tangled cocoon. With "demineralizing" the gum and structure of the cocoon is kept intact enabling the cocoons to be wet reeled. This could allow a new silk industry in areas which have not the conditions or infrastructure for raising the domesticated silk worm Bombyx mori, possibly generating a revolutionary new income stream.
The Bombyx hybrid is a hybrid between a male Bombyx mandarina moth and a female Bombyx mori moth. They produce larvae called silkworms, like all species of Bombyx. The larvae look a lot like the other variations. They are brown in the first half and gray at the bottom half, but they get larger black spots than other variations. Generally, they look like a normal Bombyx moth, but a bit darker. Hybrids are not used for silk, but for research. Because Bombyx mori males lost their ability to fly, their females are much more likely to mate with a male Bombyx mandarina. The reverse is possible, but both species have to be kept in the same container. Since Bombyx hybrids are much more common than the other variation, more is known about them.
Antheraea paphia, known as the South India small tussore, the tasar silkworm and vanya silkworm is a species of moth of the family Saturniidae found in India and Sri Lanka. The bulk of the literature on this species uses a junior synonym, Antheraea mylitta, rather than the correct name, A. paphia. It is one of a number of tasar silkworms, species that produce Tussar silk, a kind of wild silk that is made from the products of saturniid silkworms instead of the domesticated silkworm.
Gonometa postica, known commonly as the African wild silk moth, burn worm, and brandwurm, is a large species of African moth belonging to the family Lasiocampidae. The genus Gonometa boasts some very large moths and larvae; Gonometa sjostedti from Africa has a larva 16 centimeters long, for example. Most of the Lasiocampidae are highly sexually dimorphic. In G. postica the forewing of the male measures 21–25 mm and of the female 35–42 mm.
Muga silk is a variety of wild silk geographically tagged to the state of Assam in India. The silk is known for its extreme durability and has a natural yellowish-golden tint with a shimmering, glossy texture. It was previously reserved for the use of royalty. Muga is one of the three major types of indigenous wild silks produced in Assam, and is a key variety of Assam silk renowned for its natural golden color and durability.
Ahimsa silk, also known as peace silk is a method of nonviolent silk breeding and harvesting. Wild silk moths are bred rather than the domestic variety. It allows the completion of the metamorphosis of the silkworm to its moth stage, whereas most silk harvesting requires the silkworms to be killed in their cocoon stage. No animals suffer or die for the silk to be produced, making it a favorable alternative to normal silk for those who object to harming animals.
Antheraea roylei is a large moth in the family Saturniidae occurring in Nepal, Thailand, Burma, Vietnam, West Malaysia, and the Himalayan regions of India. The species is considered to be the wild progenitor of the domesticated species known as Antheraea pernyi; the theory is that pernyi may have evolved from ancestral A. roylei by chromosome rearrangement during domestication.
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