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82-468: 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

164-411: A 50 g skein of bulky wool may contain only 60 metres. Craft yarn comes in several thicknesses or weights. This is not to be confused with the measurement and weight listed above. The Craft Yarn Council of America promotes a standardized industry system for measuring yarn weight, where weights are numbered from 0 (finest) to 7 (thickest). Each weight can be described by a number and name: Size 0 yarn

246-482: A cave. Naked and cold, she spit out the net and used it as a blanket to sleep. The girl died in her sleep, and as she wished to continue to help other people, her soul turned into silkworms. Bombyx mori is essentially monophagous, exclusively eating mulberry leaves ( Morus spp.). By developing techniques for using artificial diets, the amino acids needed for development are known. The various amino acids can be classified into five categories: Moth Moths are

328-412: A central axis to facilitate yarn ball winding There are two subtypes of hanks: twisted and folded. A twisted hank is a hank that has been twisted into a rope braid. A folded hank is a hank that has been folded in half and wrapped in a label for retail purposes. Skeins are one of the most common types of yarn ball. Although skeins are technically described as yarn that has been wound into an oblong shape,

410-549: A group of insects that includes all members of the order Lepidoptera that are not butterflies . They were previously classified as suborder Heterocera, but the group is paraphyletic with respect to butterflies (suborder Rhopalocera) and neither subordinate taxon is used in modern classifications. Moths make up the vast majority of the order. There are approximately 160,000 species of moth, many of which have yet to be described. Most species of moth are nocturnal , although there are also crepuscular and diurnal species. While

492-498: A legend indicates the discovery of the silkworm's silk was by an ancient empress named Leizu , the wife of the Yellow Emperor , also known as Xi Lingshi. She was drinking tea under a tree when a silk cocoon fell into her tea. As she picked it out and started to wrap the silk thread around her finger, she slowly felt a warm sensation. When the silk ran out, she saw a small larva. In an instant, she realized this caterpillar larva

574-523: A mate, and it lacks fear of potential predators. The native color pigments have also been lost, so the domestic silk moths are leucistic , since camouflage is not useful when they only live in captivity. These changes have made B. mori entirely dependent upon humans for survival, and it does not exist in the wild. The eggs are kept in incubators to aid in their hatching. Silkworms were first domesticated in China more than 5,000 years ago. Silkworm breeding

656-449: A number of days. Silkworms have been used in antibiotic discovery, as they have several advantageous traits compared to other invertebrate models. Antibiotics such as lysocin E , a non-ribosomal peptide synthesized by Lysobacter sp. RH2180-5 and GPI0363 are among the notable antibiotics discovered using silkworms. In addition, antibiotics with appropriate pharmacokinetic parameters were selected that correlated with therapeutic activity in

738-450: A science project. Students have a chance to observe complete life cycles of insects from eggs to larvae to pupae to moths. The domestic silk moth has been raised as a hobby in countries such as China, South Africa, Zimbabwe, and Iran. Children often pass on the eggs to the next generation, creating a non-commercial population. The experience provides children with the opportunity to witness the life cycle of silk moths. The full genome of

820-532: A season, and they are generally found in and around Europe. Univoltine eggs must hibernate through the winter, ultimately cross-fertilizing in spring. Bivoltine varieties are normally found in East Asia, and their accelerated breeding process is made possible by slightly warmer climates. In addition, there are polyvoltine silkworms found only in the tropics. Their eggs typically hatch within 9 to 12 days, meaning there can be up to eight generations of larvae throughout

902-439: A silkworm that is genetically altered to produce spider silk. In September 2010, the effort was announced as successful. Researchers at Tufts developed scaffolds made of spongy silk that feel and look similar to human tissue. They are implanted during reconstructive surgery to support or restructure damaged ligaments, tendons, and other tissue. They also created implants made of silk and drug compounds which can be implanted under

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984-615: A single uniform hue, but there is also a wide selection of variegated yarns: Each of these different colours and styles are achieved through a process called yarn dyeing. There are many different methods of yarn dyeing: package dyeing, skein dyeing, space dyeing, warp beam dyeing, and more. Yarn quantities for handcrafts are usually measured and sold by weight in ounces (oz) or grams (g). Common sizes include 25g, 50g, and 100g skeins. Some companies also primarily measure in ounces with common sizes being three-ounce, four-ounce, six-ounce, and eight-ounce skeins. Textile measurements are taken at

1066-428: A smell of burnt hair; this is because many, like human hair, are protein-derived. Cotton and viscose (rayon) yarns burn as a wick. Synthetic yarns generally tend to melt, though some synthetics are inherently flame-retardant . Noting how an unidentified fiber strand burns and smells can assist in determining if it is natural or synthetic, and what the fiber content is. Both synthetic and natural yarns can pill . Pilling

1148-471: A standard temperature and humidity because variations in heat and humidity can cause fibers to absorb different amounts of moisture from the air, thus increasing the measured weight of the yarn without adding any fiber material. The actual length of the yarn contained in a ball or skein can vary due to the inherent heaviness of the fibre and the thickness of the strand; for instance, a 50 g skein of lace weight mohair may contain several hundred metres, while

1230-510: Is slub yarns, yarn with thick or thin sections alternating regularly or irregularly. In a similar manner, creating deliberate unevenness, additions or injections of neps or metallic or synthetic fibers (along with natural fibers) in spinning creates novelty yarns. Filament yarn consists of filament fibres (very long continuous fibres) either twisted together or only grouped together. Thicker monofilaments are typically used for industrial purposes rather than fabric production or decoration. Silk

1312-884: Is wool harvested from sheep . As long fibers make better yarn, sheep have been bred over time to produce longer fibers. This increases the need for shearing to prevent pests and overheating. Other animal fibers used include alpaca , angora , mohair , llama , cashmere , and silk. More rarely, yarn may be spun from camel , yak , possum , musk ox , vicuña , cat , dog , wolf , rabbit , bison , or chinchilla hair, as well as turkey or ostrich feathers. Some examples of synthetic fibers that are used as yarn are nylon , acrylic fiber , rayon , and polyester . Synthetic fibers are generally extruded in continuous strands of gel-state materials. These strands are drawn (stretched), annealed (hardened), and cured to obtain properties desirable for later processing. Synthetic fibers come in three basic forms: staple, tow, and filament. Staple

1394-464: Is a function of fiber content, spinning method, twist, contiguous staple length, and fabric construction. Single ply yarns or using fibers like merino wool are known to pill more due to the fact that in the former, the single ply is not tight enough to securely retain all the fibers under abrasion, and the merino wool's short staple length allows the ends of the fibers to pop out of the twist more easily. Yarns combining synthetic and natural fibers inherit

1476-411: Is a natural filament, and synthetic filament yarns are used to produce silk-like effects. Texturized yarns are made by a process of air texturizing filament yarns (sometimes referred to as taslanizing ), which combines multiple filament yarns into a yarn with some of the characteristics of spun yarns. They are synthetic continuous filaments that are modified to impart special texture and appearance. It

1558-769: Is a significant food resource in southern Africa . Another saturniid used as food is the cavorting emperor ( Usta terpsichore ). In one country alone, Congo , more than 30 species of moth larvae are harvested. Some are sold not only in the local village markets, but are shipped by the ton from one country to another. Nocturnal insectivores often feed on moths; these include some bats , some species of owls and other species of birds . Moths also are eaten by some species of lizards , amphibians , cats , dogs , rodents , and some bears . Moth larvae are vulnerable to being parasitized by Ichneumonidae . Baculoviruses are parasite double-stranded DNA insect viruses that are used mostly as biological control agents. They are members of

1640-484: Is aimed at the overall improvement of silkworms from a commercial point of view. The major objectives are improving fecundity , the health of larvae, quantity of cocoon and silk production, and disease resistance. Healthy larvae lead to a healthy cocoon crop. Health is dependent on factors such as better pupation rate, fewer dead larvae in the mountage, shorter larval duration (this lessens the chance of infection) and bluish-tinged fifth-instar larvae (which are healthier than

1722-404: Is called Lace, size 1 is Super Fine, size 2 is Fine, size 3 is Light, size 4 is Medium, size 5 is Bulky, size 6 is Super Bulky, and size 7 is Jumbo. Each weight also has several commonly used but unregulated terms associated with it. However, this naming convention is more descriptive than precise; fibre artists disagree about where on the continuum each lies, and the precise relationships between

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1804-565: Is composed mainly of fibroin and is produced by the larvae of the moth Bombyx mori . Silk production is thought to have begun in China and silk thread and cloth manufacture was well-established by the Shang dynasty (1600–1050 BCE). Linen is another natural fiber with a long history of use for yarn and textiles. Linen fibers are derived from the flax plant. Other plant fibers which can be spun include bamboo , hemp , maize , nettle , and soy fiber. The most common spun animal fiber

1886-405: Is composed of twisted strands of fiber, which are known as plies when grouped together. These strands of yarn are twisted together ( plied ) in the opposite direction to make a thicker yarn. Depending on the direction of this final twist, the yarn will have either s-twist (the threads appear to go "up" to the left) or z-twist (to the right). For a single ply yarn, the direction of the final twist

1968-540: Is considered more effective, but there are concerns over its effects on human health. Despite being commonly thought to be undertaken by all moths, only the larvae of several moth species eat animal fibres, creating holes in articles of clothing, in particular those made of wool. Most species do not eat fabrics, and some moth adults do not even eat at all. Some, like the Luna , Polyphemus , Atlas , Promethea , cecropia , and other large moths do not have mouth parts. This

2050-400: Is currently unknown. One hypothesis is called celestial or transverse orientation. By maintaining a constant angular relationship to a bright celestial light, such as the moon, they can fly in a straight line. Celestial objects are so far away that, even after travelling great distances, the change in angle between the moth and the light source is negligible; further, the moon will always be in

2132-467: Is cut fibers, generally sold in lengths up to 120 mm. Tow is a continuous "rope" of fibers consisting of many filaments loosely joined side-to-side. Filament is a continuous strand consisting of anything from one filament to many. Synthetic fiber is most often measured in a weight per linear measurement basis , along with cut length. Denier and Dtex are the most common weight to length measures. Cut-length only applies to staple fiber. Filament extrusion

2214-425: Is different from ring spinning . In open-end yarn, there is no roving frame stage. Sliver from the card goes into the rotor, is spun into yarn directly. Open-end yarn can be produced from short fibers. Open-end yarns are different from ring yarns. Open-end yarns are limited to coarser counts. Novelty yarns or complex yarns are yarns with special (fancy) effects introduced during spinning or plying. One example

2296-442: Is harvested. The moth is the adult phase of the silk worm's life cycle. Silk moths have a wingspan of 3–5 cm (1.2–2.0 in) and a white, hairy body. Females are about two to three times bulkier than males (due to carrying many eggs). All adult Bombycidae moths have reduced mouthparts and do not feed. The wings of the silk moth develop from larval imaginal disks . The moth is not capable of functional flight, in contrast to

2378-550: Is known to have existed since the Stone Age and earlier prehistory , with ancient fiber materials developing from animal hides , to reeds , to early fabrics. Cotton , wool , and silk were the first materials for yarn, and textile trade contributed immensely to the ancient global economy. In 2011, the Bangladesh University of Textiles established a specialized Department of Yarn Engineering, focusing on

2460-470: Is possible because they live off the food stores from when they were a caterpillar, and only live a short time as an adult (roughly a week for some species). Many species of adult moths do however eat: for instance, many will drink nectar . Items of fabric infested by clothes moth larvae may be treated by freezing them for several days at a temperature below −8 °C (18 °F). Some moths are farmed for their economic value. The most notable of these

2542-826: Is sometimes referred to as "spinning," but most people equate spinning with spun yarn production. T-shirt yarn is a recycled yarn made from the same fabric as is used in T-shirts and other clothes. It is often made from the remainder fabric of clothing manufacture, and therefore is considered a recycled and eco-friendly product. It can also be made at home out of used clothing. The resulting yarn can be used in knitted or crocheted items. In general, natural fibers tend to require more careful handling than synthetics because they can shrink, felt , stain, shed, fade, stretch, wrinkle, or be eaten by moths more readily, unless special treatments such as mercerization or super washing are performed to strengthen, fix color, or otherwise enhance

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2624-413: Is the silkworm , the larva of the domesticated moth Bombyx mori . It is farmed for the silk with which it builds its cocoon . As of 2002 , the silk industry produces more than 130 million kilograms of raw silk, worth about 250 million U.S. dollars , each year. Not all silk is produced by Bombyx mori . There are several species of Saturniidae that also are farmed for their silk, such as

2706-450: Is the same as its original twist. The twist direction of yarn can affect the final properties of the fabric, and combined use of the two twist directions can nullify skewing in knitted fabric. The mechanical integrity of yarn is derived from frictional contacts between its composing fibers. The science behind this was first studied by Galileo . Combed yarns are produced by adding another step of yarn spinning, namely combing, which aligns

2788-414: Is typically sold. The yarn is usually tied in two places directly opposite each other to keep the loops together and to keep them from tangling. Hanks are a preferred method of fastening yarn for many yarn sellers and yarn-dyers due to its ability to more widely display the qualities of the fiber. It is often wound using a swift , a standing contraption that holds a yarn hank without obstruction and spins on

2870-465: Is very common. The most widely used blends are cotton-polyester and wool-acrylic fibre blends. Blends of different natural fibres are common too, especially with more expensive fibres such as alpaca, angora and cashmere . Yarn is selected for different textiles based on the characteristics of the yarn fibres, such as warmth (wool), light weight (cotton or rayon), durability (nylon is added to sock yarn, for example), or softness (cashmere, alpaca). Yarn

2952-473: The ahimsa philosophy "not to hurt any living thing". This led to Gandhi's promotion of cotton spinning machines, an example of which can be seen at the Gandhi Institute, and an extension of this principle has led to the modern production practice known as Ahimsa silk , which is wild silk (from wild and semiwild silk moths) made from the cocoons of moths that are allowed to emerge before the silk

3034-592: The Baculoviridae , a family that is restricted to insects. Most baculovirus isolates have been obtained from insects, in particular from Lepidoptera. There is evidence that ultrasound in the range emitted by bats causes flying moths to make evasive maneuvers. Ultrasonic frequencies trigger a reflex action in the noctuid moth that causes it to drop a few centimeters or inches in its flight to evade attack, and tiger moths can emit clicks to foil bats' echolocation. The fungus Ophiocordyceps sinensis infects

3116-522: The Carboniferous period, but only evolved their characteristic proboscis alongside the rise of angiosperms in the Cretaceous period. The modern English word moth comes from Old English moððe ( cf. Northumbrian mohðe ) from Common Germanic (compare Old Norse motti , Dutch mot , and German Motte all meaning 'moth'). Its origins are possibly related to

3198-620: The Neolithic period. Before then, the tools to manufacture quantities of silk thread had not been developed. The domesticated Bombyx mori and the wild Bombyx mandarina can still breed and sometimes produce hybrids. It is unknown if B. mori can hybridize with other Bombyx species. Compared to most members in the genus Bombyx , domestic silk moths have lost their coloration as well as their ability to fly. Mulberry silkworms can be divided into three major categories based on seasonal brood frequency. Univoltine silkworms produce only one brood

3280-598: The Upper Paleolithic , and yarn spinning was one of the first processes to be industrialized . Spun yarns are produced by placing a series of individual fibres or filaments together to form a continuous assembly of overlapping fibres, usually bound together by twist. Spun yarns may contain a single type of fibre, or be a blend of various types. Combining synthetic fibres (which can have high strength, lustre, and fire retardant qualities) with natural fibres (which have good water absorbency and skin comforting qualities)

3362-470: The butterflies form a monophyletic group, the moths, comprising the rest of the Lepidoptera, do not. Many attempts have been made to group the superfamilies of the Lepidoptera into natural groups, most of which fail because one of the two groups is not monophyletic: Microlepidoptera and Macrolepidoptera , Heterocera and Rhopalocera , Jugatae and Frenatae, Monotrysia , and Ditrysia . Although

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3444-438: 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 , the practice of breeding silkworms for the production of raw silk, has existed for at least 5,000 years in China, whence it spread to India, Korea, Nepal, Japan, and then

3526-754: The Old English maða meaning ' maggot ' or from the root of midge which until the 16th century was used mostly to indicate the larva , usually in reference to devouring clothes. Moth larvae, or caterpillars , make cocoons from which they emerge as fully grown moths with wings. Some moth caterpillars dig holes in the ground, where they live until they are ready to turn into adult moths. Moths evolved long before butterflies; moth fossils have been found that may be 190 million years old. Both types of Lepidoptera are thought to have co-evolved with flowering plants , mainly because most modern species, both as adults and larvae, feed on flowering plants. One of

3608-482: The UK as tension, is a measurement of how many stitches and rows are produced per inch or per cm on a specified size of knitting needle or crochet hook. The proposed standardization uses a four-by-four inch/ten-by-ten cm knitted stockinette or single crocheted square, with the resultant number of stitches across and rows high made by the suggested tools on the label to determine the gauge. In Europe, textile engineers often use

3690-482: The West. The conventional process of sericulture kills the silkworm in the pupal stage. The domestic silk moth was domesticated from the wild silk moth Bombyx mandarina , which has a range from northern India to northern China, Korea, Japan, and the far eastern regions of Russia. The domestic silk moth derives from Chinese rather than Japanese or Korean stock. Silk moths were unlikely to have been domestically bred before

3772-426: The advanced techniques of transforming textile fibers into yarn. Yarn can be made from a number of natural or synthetic fibers , or a blend of natural and synthetic fibers. The most common plant fiber is cotton , which is typically spun into fine yarn for mechanical weaving or knitting into cloth . Silk is a natural protein fiber , some forms of which can be woven into textiles. The protein fiber of silk

3854-631: The ailanthus moth ( Samia cynthia group of species), the Chinese oak silkmoth ( Antheraea pernyi ), the Assam silkmoth ( Antheraea assamensis ), and the Japanese silk moth ( Antheraea yamamai ). The larvae of many species are used as food , particularly in Africa, where they are an important source of nutrition. The mopane worm, the caterpillar of Gonimbrasia belina , from the family Saturniidae,

3936-451: The animal survives through the pupal phase of its life cycle, it releases proteolytic enzymes to make a hole in the cocoon so it can emerge as an adult moth. These enzymes are destructive to the silk and can cause the silk fibers to break down from over a mile in length to segments of random length, which reduces the value of the silk threads , although these damaged silk cocoons are still used as "stuffing" available in China and elsewhere in

4018-848: The cocoon, which provides a layer of protection during the vulnerable, almost motionless pupal state. Many other Lepidoptera produce cocoons, but only a few — the Bombycidae, in particular the genus Bombyx , and the Saturniidae , in particular the genus Antheraea  — have been exploited for fabric production. The cocoon is made of a thread of raw silk from 300 to about 900 metres (980 to about 3,000 ft) long. The fibers are fine and lustrous, about 10 μm (0.0004 in) in diameter. About 2,000 to 3,000 cocoons are required to make one pound (0.45 kg). At least 70 million lb (32 million kg) of raw silk are produced each year, requiring nearly 10 billion cocoons. If

4100-618: The domestic silk moth was published in 2008 by the International Silkworm Genome Consortium. Draft sequences were published in 2004. The genome of the domestic silk moth is mid-range with a genome size around 432 million base pairs. A notable feature is that 43.6% of the genome are repetitive sequences , most of which are transposable elements. At least 3,000 silkworm genes are unique, and have no homologous equivalents in other genomes. The silkworm's ability to produce large amounts of silk correlates with

4182-440: The earliest known species that is thought to be an ancestor of moths is Archaeolepis mane . Its fossil fragments show scaled wings that are similar to caddisflies in their veining. Some moths, particularly their caterpillars , can be major agricultural pests in many parts of the world. Examples include corn borers and bollworms . The caterpillar of the spongy moth ( Lymantria dispar ) causes severe damage to forests in

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4264-733: The families Erebidae and Sphingidae , may be the key pollinators for some flowering plants in the Himalayan ecosystem. The roles of moths as pollinators have been studied less frequently than those of diurnal pollinators, but recent studies have established that moths are important, but often overlooked, nocturnal pollinators of a wide range of plants. Some researchers say it is likely that many plants thought to be dependent on bees for pollination also rely on moths, which have historically been less observed because they pollinate mainly at night. Moths frequently appear to circle artificial lights. The reason for this behavior (positive phototaxis )

4346-515: The family Tineidae are commonly regarded as pests because their larvae eat fabric such as clothes and blankets made from natural proteinaceous fibers such as wool or silk . They are less likely to eat mixed materials containing some artificial fibers. There are some reports that they may be repelled by the scent of wood from juniper and cedar , by lavender , or by other natural oils; however, many consider this unlikely to prevent infestation. Naphthalene (the chemical used in mothballs )

4428-907: The fiber's own properties. Some types of protein yarns (i.e., hair, silk, feathers) may feel irritating to some people, causing contact dermatitis , hives , or wheezing . These reactions are likely a sensitivity to thicker and coarser fiber diameter or fiber ends. In fact, contrary to popular belief, wool allergies are practically unknown. According to a study reviewing the evidence of wool as an allergen conducted by Acta Dermato-Venereologica, contemporary superfine or ultrafine Merino wool with their reduced fibre diameters do not provoke itch, are well tolerated and in fact benefit eczema management. Further studies suggest that known allergens applied during textile processing are minimally present in wool garments today given current industry practices and are unlikely to lead to allergic reactions. When natural hair-type fibers are burned, they tend to singe and have

4510-411: The fibres and removes the short fibres carried over from the previous step of carding. Combed yarn results in superior-quality fabrics. In comparison to carded yarns, this particular yarn is slightly more expensive, because the weaving is a long, consuming process. Combining separates small fibres from elongated fibres, in which this procedure makes the yarn softer and smoother. Hosiery yarns are used in

4592-399: The first century AD. About AD 550, Christian monks are said to have smuggled silkworms hidden in a hollow stick out of China, selling the secret to the eastern Romans. According to a Vietnamese folk tale, silkworms were originally a beautiful housemaid running away from her gruesome masters and living in the mountain, where she was protected by the mountain god. One day, a lecherous god from

4674-461: The heaven came down to Earth to seduce women. When he saw her, he tried to rape her but she was able to escape and was hidden by the mountain god. The lecherous god then tried to find and capture her by setting a net trap around the mountain. With the blessing of Guanyin , the girl was able to safely swallow that net into her stomach. Finally, the evil god summons his fellow thunder and rain gods to attack and burn away her clothes, forcing her to hide in

4756-596: The larvae of many different species of moths. Moths, like butterflies, bees and other more popularly recognized pollinating insects, serve an essential role as pollinators for many flowering plants, including species that bees do not visit. Nocturnal moths fly from flower to flower to feed on nectar during the night much as their diurnal relatives do during the day. A study conducted in the UK found moths dusted with pollen from 47 different plant species, including seven species largely ignored by bees. Some studies indicate that certain species of moths, such as those belonging to

4838-409: The larval phase of the silkworms emerge white, naked, and with little horns on their backs. After they have molted four times, their bodies become slightly yellow, and the skin becomes tighter. The larvae then prepare to enter the pupal phase of their life cycle, and enclose themselves in a cocoon made up of raw silk produced by the salivary glands . The final molt from larva to pupa takes place within

4920-635: The light source. Studies have found that light pollution caused by increasing use of artificial lights has either led to a severe decline in moth population in some parts of the world or has severely disrupted nocturnal pollination. [REDACTED] Quotations related to Moths at Wikiquote Yarn The word " yarn " comes from Middle English , from the Old English gearn , akin to Old High German garn , "yarn", Dutch garen , Ancient Greek χορδή , "string", and Sanskrit hira , "band". The human production of yarn

5002-431: The manufacturing of knitted fabrics . Since the knitted materials are more delicate than woven materials; hence hosiery yarns are made 'softer' with fewer twists per inch than their woven counterparts. Hosiery yarn comes from a separate spinning process (melt spinning), and is used with circular knitting machines to form fabric. Open-end yarn is produced by open-end spinning without a spindle . The method of spinning

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5084-492: The northeastern United States, where it is an invasive species . In temperate climates, the codling moth causes extensive damage, especially to fruit farms. In tropical and subtropical climates, the diamondback moth ( Plutella xylostella ) is perhaps the most serious pest of brassicaceous crops. Also in sub-Saharan Africa , the African sugarcane borer is a major pest of sugarcane, maize , and sorghum . Several moths in

5166-472: The oocytes of B. mori , meiosis is completely achiasmate (lacking crossovers). Even though synaptonemal complexes are formed during the pachytene stage of meiosis in B. mori , crossing-over homologous recombination does not occur between the paired chromosomes . Kraig Biocraft Laboratories has used research from the Universities of Wyoming and Notre Dame in a collaborative effort to create

5248-586: The presence of specific tRNA clusters, as well as some clustered sericin genes. Additionally, the silkworm's ability to consume toxic mulberry leaves is linked to specialized sucrase genes, which appear to have been acquired from bacterial genes. In 2018, Illumina 's short reads for 137 strain genomes were published. In 2022, Nanopore 's long reads for 545 strain genomes were published. Silk moth pupae are edible insects and are eaten in some cultures : Silkworms have also been proposed for cultivation by astronauts as space food on long-term missions. In China,

5330-424: The production of duvets , jackets, and other purposes. To prevent this, silkworm cocoons are boiled in water. The heat kills the silkworms, and the water makes the cocoons easier to unravel. Often, the silkworm is eaten. As the process of harvesting the silk from the cocoon kills the pupa, sericulture has been criticized by animal welfare and rights activists. Mahatma Gandhi was critical of silk production based on

5412-447: The properties of each parent, according to the proportional composition. Synthetics are added to lower cost, increase durability, add unusual color or visual effects, provide machine washability and stain resistance, reduce heat retention, or lighten garment weight. Spun yarn is made by twisting staple fibres together to make a cohesive thread, or "single". Twisting fibres into yarn in the process called spinning can be dated back to

5494-405: The reddish-brown ones). Quantity of cocoon and silk produced are directly related to the pupation rate and larval weight. Healthier larvae have greater pupation rates and cocoon weights. Quality of cocoon and silk depends on a number of factors, including genetics. In the U.S., teachers may sometimes introduce the insect life cycle to their students by raising domestic silk moths in the classroom as

5576-420: The role of YjbH in virulence and oxidative stress tolerance in vivo. The domestic species B. mori , compared to the wild species (e.g., B. mandarina ), has increased cocoon size, body size, growth rate, and efficiency of its digestion. It has gained tolerance to human presence and handling, and also to living in crowded conditions. The domestic silk moths cannot fly, so the males need human assistance in finding

5658-458: The rules for distinguishing moths from butterflies are not well established, one very good guiding principle is that butterflies have thin antennae and (with the exception of the family Hedylidae ) have small balls or clubs at the end of their antennae. Moth antennae are usually feathery with no ball on the end. The divisions are named by this principle: "club-antennae" (Rhopalocera) or "varied-antennae" (Heterocera). Lepidoptera first evolved during

5740-459: The silk industry is silkworms that can feed on food other than mulberry leaves, including an artificial diet. Research on the genome also raises the possibility of genetically engineering silkworms to produce proteins, including pharmacological drugs, in the place of silk proteins. Bombyx mori females are also one of the few organisms with homologous chromosomes held together only by the synaptonemal complex (and not crossovers) during meiosis . In

5822-408: The silkworm infection model. Silkworms have also been used for the identification of novel virulence factors of pathogenic microorganisms. A first large-scale screening using transposon mutant library of Staphylococcus aureus USA300 strain was performed which identified 8 new genes with roles in full virulence of S. aureus . Another study by the same team of researchers revealed, for the first time,

5904-454: The sizes. These terms include: fingering, sport, double-knit (or DK), worsted , aran (or heavy worsted), bulky, super-bulky, and roving. Another measurement of yarn weight, often used by weavers, is wraps per inch (WPI). The yarn is wrapped snugly around a ruler and the number of wraps that fit in an inch are counted. Labels on yarn for handicrafts often include information on gauge , which can also help determine yarn weight. Gauge, known in

5986-493: The skin for steady and gradual time release of medications. Researchers at the MIT Media Lab experimented with silkworms to see what they would weave when left on surfaces with different curvatures. They found that on particularly straight webs of lines, the silkworms would connect neighboring lines with silk, weaving directly onto the given shape. Using this knowledge they built a silk pavilion with 6,500 silkworms over

6068-423: The thoracic legs at different ages of the larva resulted in the adult silk moth not developing the corresponding adult leg segments. Due to its small size and ease of culture, the silkworm has become a model organism in the study of lepidopteran and general arthropod biology. Fundamental findings on genetics, pheromones, hormones, brain structures, and physiology have been made with the silkworm. One example of this

6150-415: The unit tex , which is the weight in grams of a kilometre of yarn, or decitex, which is a finer measurement corresponding to the weight in grams of 10 km of yarn. Many other units have been used over time by different industries. There are many different ways in which yarn is wound, including hanks, skeins, donut balls, cakes, and cones. A hank of yarn is a looped bundle of yarn, similar to how wire

6232-441: The upper part of the visual field, or on the horizon. When a moth encounters a much closer artificial light and uses it for navigation, the angle changes noticeably after only a short distance, in addition to being often below the horizon. The moth instinctively attempts to correct by turning toward the light, thereby causing airborne moths to come plummeting downward, and resulting in a spiral flight path that gets closer and closer to

6314-470: The wild B. mandarina and other Bombyx species, whose males fly to meet females. Some may emerge with the ability to lift off and stay airborne, but sustained flight cannot be achieved as their bodies are too big and heavy for their small wings. The legs of the silk moth develop from the silkworm's larval (thoracic) legs. Developmental genes like Distalless and extradenticle have been used to mark leg development. In addition, removing specific segments of

6396-415: The word "skein" is used generically to describe any ball of yarn. Many large-scale yarn retailers like Lion brand and parent companies like Yarnspirations sell their yarn in skeins. Unlike other types of yarn balls, a skein allows you to access both ends of the yarn. The yarn end in the inside of the skein is called a center pull. One major complaint of center pull bullet skeins is that the inside yarn end

6478-456: The year. Eggs take about 14 days to hatch into larvae, which eat continuously. They have a preference for white mulberry , having an attraction to the mulberry odorant cis-jasmone . They are not monophagous , since they can eat other species of Morus , as well as some other Moraceae , mostly Osage orange . They are covered with tiny black hairs. When the color of their heads turns darker, it indicates they are about to molt . After molting,

6560-459: Was originally applied to synthetic fibers to reduce transparency, slipperiness and increase warmth, absorbency and makes the yarn more opaque. It was used to manufacture a variety of textile products: knitted underwear and outer wear, shape-retaining knitted suits, overcoats. They also were used in the production of artificial fur, carpets, blankets, etc. Yarn may be used undyed, or may be coloured with natural or artificial dyes . Most yarns have

6642-512: Was the molecular identification of the first known pheromone, bombykol , which required extracts from 500,000 individuals, due to the small quantities of pheromone produced by any individual silkworm. Many research works have focused on the genetics of silkworms and the possibility of genetic engineering. Many hundreds of strains are maintained, and over 400 Mendelian mutations have been described. Another source suggests 1,000 inbred domesticated strains are kept worldwide. One useful development for

6724-400: Was the source of the silk. She taught this to the people and it became widespread. Many more legends about the silkworm are told. The Chinese guarded their knowledge of silk, but, according to one story, a Chinese princess given in marriage to a Khotan prince brought to the oasis the secret of silk manufacture, "hiding silkworms in her hair as part of her dowry", probably in the first half of

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