Silkworm The Silkworm, Bombyx mori produces the silk of commercial importance It is the caterpillar of a moth whose cocoon is used to make.
Contents.Eri silk The common name, ailanthus silkmoth, refers to the host plant. There is a subspecies, S.
Cynthia ricini in India and Thailand that feeds upon the leaves of, and is known for the production of, and is often referred to by the common name eri silkmoth.The eri silk worm 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. Ailanthus silkmoth diversity (with specimens included in first two rows) Eggs Whitish eggs, marked with brown, are laid in rows of 10 to 20 on leaves in crescents.
Hatching takes 7–10 days.Larvae Larvae are and yellow at first. Later are solitary, and whitish green with white tubercules along the back, and small black dots. There are five instars, and they reach a maximum length 70–75 mm.Pupae A silken off-white to grey cocoon is spun on the leaves of the host. It has an obvious escape hatch.Adults Females prepare to mate in the evening or night after emerging in late morning. Adult flight is during May and June in northern Europe, as one generation. In southern Europe a partial second generation may occur in September. Adults lack mouth parts and can neither eat nor drink.Food plants Larvae will feed on other trees and shrubs, but all eggs are laid on the 'tree of heaven' ( ) and growth is best on it.
This tree is commonly grown as an ornamental in cities. The subspecies S. Cynthia ricini feeds upon.See also.References. 'The Queen of Textiles.' National Geographic Magazine. 1, January, 1984, pp.
2-49. Peigler, R.S.
& Naumann, S., 2003. A Revision of the Silkmoth Genus Samia. San Antonio: University of the Incarnate Word. 230 pp., 10 maps, 228 figs. Wangkiat, Paritta (19 February 2017).
Bangkok Post. Retrieved 19 February 2017.Further reading. Tuskes, PM, JP Tuttle and MM Collins. The Wild Silk Moths of North America. Cornell University Press.External links has information related toWikimedia Commons has media related to. Lotts, Kelly & Naberhaus, Thomas (2017).
Butterflies and Moths of North America. Retrieved November 11, 2018. (YouTube video). (YouTube video).
Contents.Types Mulberry silkworms can be categorized into three different but connected groups or types. The major groups of silkworms fall under the univoltine ('uni-'=one, 'voltine'=brood frequency) and bivoltine categories.
The univoltine type is generally linked with the geographical area within greater Europe. The eggs of this type hibernate during winter due to the cold climate, and cross-fertilize only by spring, generating silk only once annually. The second type is called bivoltine and is normally found in,. The breeding process of this type takes place twice annually, a feat made possible through the slightly warmer climates and the resulting two life cycles.
The polyvoltine type of mulberry silkworm can only be found in the tropics. The eggs are laid by female moths and hatch within nine to 12 days, so the resulting type can have up to eight separate life cycles throughout the year. Wild silk mothEggs take about 14 days to hatch into larvae, which eat continuously. They have a preference for, having an attraction to the mulberry odorant. They are not, since they can eat other species of, as well as some other, mostly.
They are covered with tiny black hairs. When the color of their heads turns darker, it indicates they are about to. After molting, the 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 phase of their lifecycle, and enclose themselves in a cocoon made up of raw silk produced by the. The final molt from larva to pupa takes place within the cocoon, which provides a vital layer of protection during the vulnerable, almost motionless pupal state. Many other produce cocoons, but only a few—the, in particular the genus, and the, in particular the genus —have been exploited for fabric production.If the animal is allowed to survive after spinning its cocoon and through the pupal phase of its lifecycle, it releases 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 seriously reduces the value of the silk, but not silk cocoons used as 'stuffing' available in China and elsewhere for doonas, jackets, etc. To prevent this, silkworm cocoons are boiled. The heat kills the silkworms and the water makes the cocoons easier to unravel. Often, the silkworm itself is eaten.As the process of harvesting the silk from the cocoon kills the larva, sericulture has been criticized by animal welfare and rights activists.
Was critical of silk production based on the 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. He also promoted, made from the cocoons of wild and semiwild silk moths.The moth – the adult phase of the lifecycle – is not capable of functional flight, in contrast to the wild B.
Mandarina and other Bombyx species, whose males fly to meet females and for evasion from predators. Some may emerge with the ability to lift off and stay airborne, but sustained flight cannot be achieved.
This is because their bodies are too big and heavy for their small wings. However, some silk moths can still fly. 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 (for they are carrying many eggs), but are similarly colored. Adult have reduced mouthparts and do not feed, though a human caretaker can feed them.Cocoon. 1679 study of the silkworm metamorphosis by, it depicts the fruit and leaves of a tree and the eggs and larvae of the silkworm moth.Due to its small size and ease of culture, the silkworm has become a in the study of lepidopteran and arthropod biology. Fundamental findings on, brain structures, and physiology have been made with the silkworm. One example of this was the molecular identification of the first known pheromone, which required extracts from 500,000 individuals, due to the very small quantities of pheromone produced by any individual silkworm.
Currently, research is focusing on the genetics of silkworms and the possibility of genetic engineering. Many hundreds of strains are maintained, and over 400 have been described. Another source suggests 1,000 inbred domesticated strains are kept worldwide. One useful development for 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 (and not crossovers) during.has used research from the and in a collaborative effort to create a silkworm that is genetically altered to produce spider silk. In September 2010, the effort was announced as successful.Researchers at 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 the skin for steady and gradual time release of medications.Researchers at the 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 with 6,500 silkworms over a number of days.Silkworms have been used in antibiotics 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.Domestication The domestic species, compared to the wild species, 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 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 the domesticated strains entirely dependent upon humans for survival.
The eggs are kept in to aid in their hatching.Silkworm breeding. Silkworm cocoons weighed and sorted (Liang Kai's Sericulture)Silkworm breeding is aimed at the overall improvement of silkworms from a commercial point of view. The major objectives are improving (the egg-laying capacity of a breed), 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 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 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.Hobby raising and school projects In the U.S., teachers may sometimes introduce the insect life cycle to their students by raising domestic silk moths in the classroom as 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, creating a non-commercial population. The experience provides children with the opportunity to witness the life cycle of silk moths. The practice of raising silk moths by children as pets has, in non-silk farming South Africa, led to the development of extremely hardy of silk moths, because they are invariably subjected to hardships not encountered by commercially farmed members of the species. However, these worms, not being selectively bred as such, are possibly inferior in silk production and may exhibit other undesirable traits.Genome The full of 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 around 432 megabase pairs.High genetic variability has been found in domestic lines of silk moths, though this is less than that among wild silk moths (about 83 percent of wild genetic variation). This suggests a single event of domestication, and that it happened over a short period of time, with a large number of wild silkworms having been collected for domestication.
Major questions, however, remain unanswered: 'Whether this event was in a single location or in a short period of time in several locations cannot be deciphered from the data'. Research also has yet to identify the area in China where domestication arose. Packaged silkworm snacks from ThailandSilk moth pupae are in some cultures. In, they are boiled for extracting silk and the boiled pupae are eaten directly with salt or fried with chili pepper or herbs as a snack or dish. In, they are boiled and seasoned to make a popular snack food known as (번데기).
In, street vendors sell roasted silk moth pupae. In, silkworms are usually served as a (佃煮), i.e., boiled in a sweet-sour sauce made with and sugar. In, this is known as con nhộng.
In, roasted silkworm is often sold at open markets. They are also sold as packaged snacks.
Silkworms have also been proposed for cultivation by astronauts as on long-term missions.Silkworm legends China. See also:In China, a legend indicates the discovery of the silkworm's silk was by an ancient empress named, the wife of the, 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 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 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 the first century AD. About AD 550, Christian monks are said to have smuggled silkworms, in a hollow stick, out of China and sold the secret to the.Vietnam 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 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 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, 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 a cave. Naked and cold, she spitted 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.Silkworm diseases., a fungus, destroys the entire silkworm body. This fungus usually appears when silkworms are raised under cold conditions with high humidity.
This disease is not passed on to the eggs from moths, as the infected silkworms cannot survive to the moth stage. This fungus, however, can spread to other insects., also known as nuclear polyhedrosis, milky disease, or hanging disease, is caused by infection with the Bombyx mori nucleopolyhedrovirus (aka Bombyx mori nuclear polyhedrosis virus, genus ). If grasserie is observed in the chawkie stage, then the chawkie larvae must have been infected while hatching or during chawkie rearing. Infected eggs can be disinfected by cleaning their surfaces prior to hatching.
Infections can occur as a result of improper hygiene in the chawkie rearing house. This disease develops faster in early instar rearing. is a disease caused by a parasitic microsporidian,. Diseased larvae show slow growth, undersized, pale and flaccid bodies, and poor appetite.
Tiny black spots appear on larval integument. Additionally, dead larvae remain rubbery and do not undergo putrefaction after death.
Bombycis kills 100% of silkworms hatched from infected eggs. This disease can be carried over from worms to moths, then to eggs and worms again. This microsporidium comes from the food that the silkworms eat. Female moths pass the disease to the eggs, and 100% of silkworms hatching from the diseased eggs will die in their worm stage. To prevent this disease, it is extremely important to rule out all eggs from infected moths by checking the moth's body fluid under a microscope. infected silkworms look weak and are colored dark brown before they die.
The disease destroys the larva's gut and is caused by viruses or poisonous food. Several diseases caused by a variety of funguses are collectively named.See also.References.
Barber (1992). Arunkumar; Muralidhar Metta; J. Nagaraju (2006). 40 (2): 419–427. Hideaki Maekawa; Naoko Takada; Kenichi Mikitani; Teru Ogura; Naoko Miyajima; Haruhiko Fujiwara; Masahiko Kobayashi; Osamu Ninaki (1988). 'Nucleolus organizers in the wild silkworm Bombyx mandarina and the domesticated silkworm B.
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Routledge, 1994. Page 131.Further reading. Kelly, Henrietta Aiken (1903). Washington DC:,. Retrieved 17 January 2012.; (2005). Evolution of the Insects.
Johnson, Sylvia (1989). Scoble, M. The Lepidoptera: Form, Function and Diversity. Yoshitake, N. 'Phylogenetic aspects on the origin of Japanese race of the silkworm, Bombyx mori L.' Journal of Sericological Sciences of Japan. 37: 83–87.
Trevisan, Adrian. Sense of Nature.
Archived from on 7 May 2012. Wolchover, Natalie. Seed Magazine.
Archived from on 26 March 2017. Retrieved 1 May 2012.External links Wikimedia Commons has media related to. 1943 article with first photographic study of subject.
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