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Bombyx mori 1 Bombyx mori Domesticated Silkmoth Silkworm Paired male (above) and female (below) Fifth instar silkworm larvae. Conservation status Domesticated Scientific classification Kingdom: Animalia Phylum: Arthropoda Class: Insecta Order: Lepidoptera Family: Bombycidae Genus: Bombyx Species: B. mori Binomial name Bombyx mori Linnaeus, 1758 Synonyms Silkworm The silkworm is the larva or caterpillar of the domesticated silkmoth, Bombyx mori (Latin: "silkworm of the mulberry tree"). It is an important economic insect since it is the producer of silk. A silkworm's preferred food is white mulberry leaves, but it may also eat the leaves of the Osage Orange or the Tree of Heaven. It is entirely dependent on humans for its reproduction and no longer occurs naturally in the wild. Sericulture has been practised for at least 5,000 years in China. It was domesticated from the wild silkmoth Bombyx mandarina which has a range from northern India to northern China, Korea, Japan and far eastern Russia. It derives from Chinese rather than Japanese or Korean stock. [1] The breeding of silkworms cannot have originated before the Neolithic as the tools necessary to make use of the silk thread on a large scale only have become available since then. The domesticated and wild species can still breed and so hybridize together.

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Page 1: Bombyx mori

Bombyx mori 1

Bombyx mori

Domesticated SilkmothSilkworm

Paired male (above) and female (below)

Fifth instar silkworm larvae.

Conservation status

Domesticated

Scientific classification

Kingdom: Animalia

Phylum: Arthropoda

Class: Insecta

Order: Lepidoptera

Family: Bombycidae

Genus: Bombyx

Species: B. mori

Binomial name

Bombyx moriLinnaeus, 1758

Synonyms

Silkworm

The silkworm is the larva or caterpillar of the domesticated silkmoth, Bombyx mori (Latin: "silkworm of themulberry tree"). It is an important economic insect since it is the producer of silk. A silkworm's preferred food iswhite mulberry leaves, but it may also eat the leaves of the Osage Orange or the Tree of Heaven. It is entirelydependent on humans for its reproduction and no longer occurs naturally in the wild. Sericulture has been practisedfor at least 5,000 years in China.It was domesticated from the wild silkmoth Bombyx mandarina which has a range from northern India to northernChina, Korea, Japan and far eastern Russia. It derives from Chinese rather than Japanese or Korean stock.[1] Thebreeding of silkworms cannot have originated before the Neolithic as the tools necessary to make use of the silkthread on a large scale only have become available since then. The domesticated and wild species can still breed andso hybridize together.

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The full genome of the silkworm was published in 2008 by the International Silkworm Genome Consortium.[2]

DevelopmentEggs take about ten days to hatch. They eat continuously. They have a preference for White Mulberry having anattraction to the mulberry oderant cis-jasmone. They are not monophagous since they can eat other species of Morusas well as some other Moraceae. Hatchlings and second-instar larvae are called kego and chawki in India. They arecovered with tiny black hairs. When the color of their heads turns darker, it indicates that they are about to molt.Later instars are white, naked, and have a horn on the back.After they have molted four times (i.e., in the fifth instar), their bodies turn slightly yellow and their skin becomestighter. The larvae enclose themselves in a cocoon of raw silk produced in the salivary glands that providesprotection during the vulnerable, almost motionless pupal state. Many other Lepidoptera produce cocoons, but only afew -- the Bombycidae (in particular the Bombyx genus) and the Saturniidae (in particular the Antheraea genus) --have been exploited for fabric production.The cocoon is made of a thread of raw silk from 300 to about 900 meters (1,000 to 3,000 feet) long. The fibers arevery fine and lustrous, about 10 micrometers (1/2,500th of an inch) in diameter. About 2,000 to 3,000 cocoons arerequired to make a pound of silk. Based on 1 kilometer (about 1,100 yards) per cocoon, ten unraveled cocoons couldtheoretically extend vertically to the height of Mount Everest. At least 70 million pounds of raw silk are producedeach year, requiring nearly 10 billion pounds of mulberry leaves. According to E. L. Palmer one pound of silkrepresents about 1,000 miles of filament. The annual world production represents 70 billion miles of silk filament, adistance well over 300 round trips to the sun. Silk produced yearly is not only consumed in the fabric industry forclothing, but is also used in the medical industry. The suture material mersilk, a non-absorbable, polyfilament,braided suture is composed of the organic protein fibroin produced by larvae of Bombyx mori. This silk is usuallyprocessed to remove natural waxes and gums, for example sericin gum. It is sometimes subsequently dyed.If the animal is allowed to survive after spinning its cocoon, it will release proteolytic enzymes to make a hole in thecocoon so that it can emerge as a moth. This would cut short the threads and ruin the silk. To prevent this, silkwormcocoons are boiled. The heat kills the silkworms and the water makes the cocoons easier to unravel. Often, thesilkworm itself is eaten (see Cuisine).The adult phase (the moth) cannot fly. The silkmoths have a wingspan of 3-5 cm (1.5 - 2 inches) and a white hairybody. Females have about twice to three times the bulk of males (for they are carrying many eggs), but are similarlycolored. Adults in the Bombycidae have reduced mouth parts and do not feed, though a human caretaker can alsofeed them.

ResearchDue to its large size and ease of culture, the silkworm has become a model organism in the study of Lepidopteranand arthropod biology. Fundamental findings on pheromones, hormones, brain structures and physiology have beenmade with the silkworm. One example of this was the molecular identification of the first known pheromone,bombykol which required extracts from 500,000 individuals due to the very small quantities of pheromone producedby any individual worm.Currently, research is focusing on genetics of silkworms and the possibility of genetic engineering. Many hundredsof strains are maintained, and over 400 Mendelian mutations have been described. Another source suggests 1000inbred domesticated strains are kept worldwide.[2] One useful development for the silk industry are silkworms thatcan feed on food other than mulberry leaves, including an artificial diet. Also research upon the genome raising thepossibility of genetic engineering of silkworms to produce proteins including pharmacological drugs in the place ofsilk proteins.

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DomesticationThe domesticated variety compared to the wild form has increased cocoon size, growth rate and efficiency of itsdigestion. It has also gained tolerance to human presence and handling and living in crowded conditions. It alsocannot fly and lacks fear of potential predators. These changes have made it entirely dependent upon humans fortheir survival.[3]

Silkworm breeding: Silkworm is one of the most genetically exploited animals. Silkworms were first domesticatedduring the ‘Han Dynasty’ in China about 5000 years ago. Since then the silk production capacity of the species hasincreased nearly ten folds. Silkworm is one of the few organisms wherein the principles of genetics and breedingwere applied to harvest maximum output. It is next only to maize in exploiting the principles of ‘heterosis’ and ‘crossbreeding’ Silkworm breeding is aimed at the overall improvement of silkworm in a human-commercial point ofview. The major objectives of silkworm breeding are: Improving fecundity, improving healthiness of larvae,improving quantity of cocoon and silk production, improving quality of cocoon and silk production, for specificpurposes based on cocoon and silk production, for disease resistance etc. Let us discuss each of this in short.Fecundity: it refers to the egg laying capacity of a breed. It is a very important factor since commercial sericulture isstrongly dependent on silkworm egg. Healthiness of larvae: healthy larvae lead to healthy cocoon crop. Healthinessis dependent on factors such as better pupation rate, less number of dead larvae in the mountage, shorter larvalduration (shorter the larval duration lesser the chances of infection) and bluish tinged fifth instar larvae (it isobserved that bluish colored fifth instar larvae are healthier than the reddish brown ones). Quantity of cocoon andsilk: Quantity of cocoon produced is directly related to the pupation rate and larval weight. Healthier the larva morewill be the pupation rate and cocoon weight. Quality of cocoon and silk: This depends upon a number of factorsincluding genetic factors. Specific purposes: Apart from commercial purpose advanced countries are giving attentionto specific breed development for specific purposes like sericin production, sex limited breeds, thin/ thick filamentproduction etc. Disease resistance breeding: The major reason for crop losses is pathogen infection. Efforts are invogue to evolve breeds which are tolerant or resistant to various pathogens. [4]Silkworm Raising For Entertainment: The silkworm has been raised for entertainment in China. Children oftenpass on the eggs, creating a non-commercial population. The experience provides children with the opportunity towitness the lifecycle of silkworms.

GenomeThe genome of the silkworm is mid-range with a genome size of ~432 Mb. It was published in 2008 by theInternational Silkworm Genome Consortium.[2] A draft sequence was published in 2004.[5]

High genetic variability has been found in domestic lines of silkworms though this is less than that among wildsilkmoths (~83%). This suggests that was a single event of domestication and that this happened over a short periodof time with a large number of wild worms being collected for domestication.[6] However major questions remainunanswered: “Whether this event was in a single location or in a short period of time in several locations cannot bedeciphered from the data,” Research also has yet to identify the area in China where domestication arose.[7]

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CuisineLike many insect species, silkworm pupae are eaten in some cultures (see Entomophagy). In Korea they are boiledand seasoned to make a popular snack food known as beondegi. In China street vendors sell roasted silkworm pupae.Silkworms have also been proposed for cultivation by astronauts as space food on long-term missions.[8]

Silkworm legendsIn China, there is a legend that the discovery of the silkworm's silk was by an ancient empress called Xi Ling-Shi.She was drinking tea under a tree when a silk cocoon fell into her tea. She picked it out and started to wrap the silkthread around her finger, she slowly felt a warm sensation. When the silk ran out, she saw a small larva. In aninstant, she realized that this caterpillar larva was the source of the silk. She taught this to the people and it becamewidespread. There are many more legends about the silkworm.The Chinese guarded their knowledge of silk. It is said that a Catholic priest smuggled silkworms, in a hollow stick,out of China and sold the secret to Europe.

Traditional Chinese medicineSilkworm is the source of the "stiff silkworm". This is made from the dried body of the 4-5th instar larva which hasdied of the white muscardine disease. Its uses are to dispel flatulence, dissolve phlegm and relieve spasms.

Gallery

Females layingeggs

7-day (secondinstar) kego

Male adult. Scale is 15 mm Female adult. Scale is 20 mm

Silkworm in action, spinning athread

Silkworm, 5th instar. Fifth instar silkworm larvae,clustered on a leaf.

Silkwormcocoons.

Silkworm moth femalereproductive organ.

A female silkworm moth perchedon a cocoon.

Silkworm eggs laid on anothercocoon.

Cocoons

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A female silkworm moth layingeggs.

See also• History of Silk• Silk Road• Sericulture

References• Grimaldi & Engel (2005): Evolution of the Insects. Cambridge University Press.• Johnson, Sylvia (1989): Silkworms. Lerner Publications. Children's book with lots of photos.• Maekawa, H.; Takada, N.; Mikitani, K.; Ogura, T.; Miyajima, N.; Fujiwara, H.; Kobayashi, M. & Ninaki, O.

(1988): Nucleolus organizers in the wild silkworm Bombyx mandarina and the domesticated silkworm B. mori.Chromosoma 96: 263–269. doi:10.1007/BF00286912 (HTML abstract)

• Scoble, M.J. (1995): The Lepidoptera: Form, function and diversity. Princeton University Press.• Yoshitake, N. (1968): Phylogenetic aspects on the origin of Japanese race of the silkworm, Bombyx mori L..

Journal of Sericological Sciences of Japan 37: 83–87.

External links• Student page on silkworm [9]

• WormSpit, a site about silkworms, silkmoths, and silk [10]

• Information about silkworms for classroom teachers with many photos [11]

• SilkBase Silkworm full length cDNA Database [12]

• Silkworm breeding-certain fundamental thoughts [4]

References[1] Maekawa et al. 1988, Arunkumar et al. 2006[2] The International Silkworm Genome Consortium (2008). The genome of a lepidopteran model insect, the silkworm Bombyx mori Insect

Biochemistry and Molecular Biology, 38 (12) 1036-1045 doi:10.1016/j.ibmb.2008.11.004[3] Goldsmith MR, Shimada T, Abe H. (2005). The genetics and genomics of the silkworm, Bombyx mori. Annu Rev Entomol. 50:71-100.

PMID 15355234[4] http:/ / silkwormmori. blogspot. com/ 2008/ 08/ silkworm-breeding-certain-fundamental. html[5] Mita, Kazuei; Kasahara, Masahiro; Sasaki, Shin; Nagayasu, Yukinobu; Yamada, Tomoyuki; Kanamori, Hiroyuki; Namiki, Nobukazu;

Kitagawa, Masanari; Yamashita, Hidetoshi; Yasukochi, Yuji; Kadono-Okuda, Keiko; Yamamoto, Kimiko; Ajimura, Masahiro; Ravikumar,Gopalapillai; Shimomura, Michihiko; Nagamura, Yoshiaki; Shin-i, Tadasu; Abe, Hiroaki; Shimada, Toru; Morishita, Shinichi & Sasaki,Takuji (2004): The Genome Sequence of Silkworm, Bombyx mori. DNA Research 11(1): 27-35. PMID 15141943. doi:10.1093/dnares/11.1.27PDF fulltext (http:/ / dnaresearch. oxfordjournals. org/ cgi/ reprint/ 11/ 1/ 27. pdf)

[6] Xia Q, Guo Y, Zhang Z}, Li D, Xuan Z, Li Z. et al,. (2009). Complete Resequencing of 40 Genomes Reveals Domestication Events andGenes in Silkworm (Bombyx). Science, doi:10.1126/science.1176620

[7] Normile D. (2009). Sequencing 40 Silkworm Genomes Unravels History of Cultivation. Science, 325(5944) 1058 - 1059.doi:10.1126/science.325_1058a

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[8] Choi, Charles Q. (13 January 2009). "Care for a Silkworm With Your Tang?" (http:/ / www. newsguide. us/ education/ science/Care-for-a-Silkworm-With-Your-Tang/ ?date=2009-01-14). ScienceNOW Daily News. . Retrieved 2009-01-14 (accessed through NewsGuideUS).

[9] http:/ / animaldiversity. ummz. umich. edu/ site/ accounts/ information/ Bombyx_mori. html[10] http:/ / www. wormspit. com/ index. htm[11] http:/ / www. suekayton. com/ silk. htm[12] http:/ / morus. ab. a. u-tokyo. ac. jp

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Article Sources and Contributors 7

Article Sources and ContributorsBombyx mori  Source: http://en.wikipedia.org/w/index.php?oldid=362750966  Contributors: -Ril-, .:Ajvol:., Accuruss, Adhib, Aintneo, Aitias, Almafeta, Alphachimp, Amaltheus, Amillar,Andre Engels, Animum, Annarchy, Anty, Apokryltaros, AshLin, Avihu, Azhyd, BaldPark, Balthazarduju, Beebopbeth, Biotecharun, Bjwebb, Bluemoose, Bobo192, Bogdangiusca,Bohemianroots, Bradjamesbrown, Byucougarfan, Chenx064, Chip Fillingane, Chistylefries, ChongDae, ChrisHodgesUK, Closedmouth, CommonsDelinker, Cyclopia, Dalf, Dandelions, DanielKellis, Dferg, DocLightning, Download, Dr. Chu, Dracontes, DragonflySixtyseven, Dysmorodrepanis, ERcheck, Elizadripping, Epbr123, Eraserhead1, Eve Hall, Everyking, Excirial, Fastily,Feifuga, Fennec, Fullback 12, G-my, Gkrajeshrajesh, Goldfinger820, Gökhan, HenkvD, Henry Flower, Hephaestos, Hesperian, Hgamboa, Hibernian, Hobo loquens, Hunter Kahn, Imc,InShaneee, JBazuzi, Jimfbleak, Jjport1995, Jkisch, JoergenB, Jose77, JudgeSpear, Kandar, Karch, Karen Johnson, Kuang, Kugamazog, Kummi, Kuru, LaBohemienne, Leevclarke, LittleHow,Locutus, Lol o fat bat, Lowellian, Lysis rationale, MK8, Marek69, Marginoferror, Mav, Mconst, Melburnian, Miceweed, Michael Hardy, Mirror Vax, Mister Six, Monkey Bounce, Monre, Muke,Nautilusfossil, Nehrams2020, Newone, NocturneNoir, Nsaa, Oakenking, Octahedron80, Oreo Priest, Ortolan88, Ossmann, Pekinensis, Perlscrypt, Petru Dimitriu, Phr, Pidgey33, PierreAbbat, PietDelport, Pingveno, Pink pies, Pippu d'Angelo, Plindenbaum, Pmcalduff, Pro bug catcher, Pschemp, Pterodactyler, Qst, Quinsareth, Ratemonth, Rees11, Richard Barlow, Rnb, Rockstone35,Sander123, Sandstein, Sarefo, Satyrium, Sergio sanchez, Serpens, Shadowjams, Shanes, Staffel, Stemonitis, Stephenb, SteveSims, Stevegallery, Stevenj, Stwalkerster, Sumanthk, Supernovacaine,Taichi, TheLeopard, TheMaster17, Themusicking, Tocharianne, Tolleyl, Tom or Jerry, Tony Fox, Toytoy, Tree Biting Conspiracy, WDavis1911, Wakablogger2, Williamb, Yath, Yjxiao, Yosri,Zapvet, கலை, 234 anonymous edits

Image Sources, Licenses and Contributorsfile:Pairedmoths.jpg  Source: http://en.wikipedia.org/w/index.php?title=File:Pairedmoths.jpg  License: Creative Commons Attribution-Sharealike 2.5  Contributors: Closedmouth, Oakenking,Zappernapper, 3 anonymous editsfile:Silkworms3000px.jpg  Source: http://en.wikipedia.org/w/index.php?title=File:Silkworms3000px.jpg  License: GNU Free Documentation License  Contributors: Fastily (talk). Originaluploader was Fastily at en.wikipediaImage:Bombyx mori 01.jpg  Source: http://en.wikipedia.org/w/index.php?title=File:Bombyx_mori_01.jpg  License: GNU Free Documentation License  Contributors: MushiHoshiIshi, WeFtImage:Bombyx mori Caterpillar 02.jpg  Source: http://en.wikipedia.org/w/index.php?title=File:Bombyx_mori_Caterpillar_02.jpg  License: GNU Free Documentation License  Contributors:MushiHoshiIshi, WeFtImage:BombyxMale.jpg  Source: http://en.wikipedia.org/w/index.php?title=File:BombyxMale.jpg  License: Public Domain  Contributors: CetoineImage:BombyxFemelle.jpg  Source: http://en.wikipedia.org/w/index.php?title=File:BombyxFemelle.jpg  License: Public Domain  Contributors: CetoineImage:Silkworm silkthreads.jpg  Source: http://en.wikipedia.org/w/index.php?title=File:Silkworm_silkthreads.jpg  License: Creative Commons Attribution-Sharealike 3.0  Contributors:User:Tom or JerryFile:Silkwormheadsm.jpg  Source: http://en.wikipedia.org/w/index.php?title=File:Silkwormheadsm.jpg  License: Creative Commons Attribution-Sharealike 2.5  Contributors: User:EleassarImage:4thInstarLarvae3500px.jpg  Source: http://en.wikipedia.org/w/index.php?title=File:4thInstarLarvae3500px.jpg  License: Creative Commons Attribution-Sharealike 3.0  Contributors:User:FastilyImage:Ipek-kozasi.jpg  Source: http://en.wikipedia.org/w/index.php?title=File:Ipek-kozasi.jpg  License: Free Art License  Contributors: user:katpatukaImage:Silkwormmothtailorgan3500ppx.JPG  Source: http://en.wikipedia.org/w/index.php?title=File:Silkwormmothtailorgan3500ppx.JPG  License: Creative Commons Attribution-Sharealike3.0  Contributors: User:FastilyImage:FemaleSilkwormmoth3500ppx.jpg  Source: http://en.wikipedia.org/w/index.php?title=File:FemaleSilkwormmoth3500ppx.jpg  License: Creative Commons Attribution-Sharealike 3.0 Contributors: User:FastilyImage:Silkwormeggs3500ppx.jpg  Source: http://en.wikipedia.org/w/index.php?title=File:Silkwormeggs3500ppx.jpg  License: Creative Commons Attribution-Sharealike 3.0  Contributors:User:FastilyFile:Bombyxmoriemptycocoon3800ppx.jpg  Source: http://en.wikipedia.org/w/index.php?title=File:Bombyxmoriemptycocoon3800ppx.jpg  License: Creative Commons Attribution-Sharealike3.0  Contributors: User:FastilyFile:Bombyxmori3800ppx4.jpg  Source: http://en.wikipedia.org/w/index.php?title=File:Bombyxmori3800ppx4.jpg  License: Creative Commons Attribution-Sharealike 3.0  Contributors:User:Fastily

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