Bombyx mori 70866 224317569 2008-07-08T09:08:52Z Synthebot 3658625 robot Adding: [[bg:Копринена буба]] {{redirect|Silkworm}} {{Taxobox | name = Domesticated Silkmoth<br/>Silkworm | image = Pairedmoths.jpg | image_width = 240px | image_caption = Paired male (above) and female (below) | image2 = Silkwormheadsm.jpg | image2_width = 240px | image2_caption = Silkworm, 4th or 5th [[instar]] | status = DOM | regnum = [[Animal]]ia | phylum = [[Arthropod]]a | classis = [[Insect]]a | ordo = [[Lepidoptera]] | familia = [[Bombycidae]] | genus = ''[[Bombyx]]'' | species = '''''B. mori''''' | binomial = ''Bombyx mori'' | binomial_authority = [[Carolus Linnaeus|Linnaeus]], [[Systema Naturae|1758]] | synonyms = ''Bombyx mori mori'' }} The '''silkworm''' is the [[larva]] or [[caterpillar]] of '''''Bombyx mori''''' ([[Latin]]: "silkworm of the [[mulberry]] tree"), the '''domesticated silkmoth'''. A [[moth]] in the family [[Bombycidae]], it is very important economically as the producer of [[silk]]. It is entirely dependent on humans for its reproduction and no longer occurs naturally in the wild. Silk culture has been practiced for at least 5,000 years in China (Goldsmith ''et al.'' 2004). A silkworm's preferred food is [[White Mulberry]] leaves. It is native to northern [[China]]. Its nearest wild relative is ''[[Bombyx mandarina]]'' which is able to hybridize with the domestic [[taxon]] (Goldsmith ''et al.'' 2004), and which ranges from northern India to northern China, Korea and Japan. It is not known when the domestic silkmoth diverged from its wild relatives, only that the domestic population originated from inland Chinese rather than Japanese or Korean stock (Maekawa ''et al.'' 1988, Arunkumar ''et al.'' 2006). [[Molecular clock]] studies suggesting an age of many millions of years{{Fact|date=July 2007}} cannot be taken seriously, as they assume that both species have [[evolved]] with constant speed since their divergence.{{Fact|date=September 2007}} This is not correct however due to the domestication process having accelerated the pace of evolution (a similar problem affects the attempt to resolve the [[phylogeny]] of domestic [[Western honey bee]] subspecies). In fact, the domestic silkworm has undergone such strong [[artificial selection]] that it is completely unable to survive in the wild for any length of time. It is probably the most heavily [[domesticated]] animal known apart from domestic [[Hybrid (biology)|hybrid]]s such as [[mule]]s. Regardless whether the domestic silkworm is derived from a wild species that has since gone [[extinct]], or from a stock of ''Bombyx mandarina'' that was taken into human care some 4,600 years ago (Yoshitake 1968), 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. Sometimes, the Wild Silkmoth is considered a [[subspecies]] of ''Bombyx mori'' (the older [[specific name]] is used as per [[ICZN]] rules) as they are theoretically capable of full hybridization. However, due to the domesticated moth's requirement for human care to survive, [[gene flow]] is all but nonexistent and thus, despite its apparently recent origin, the domestic animal is generally treated as a distinct [[monotypic]] species today. ==Development== Eggs take about ten days to hatch. Silkworms have a strong appetite, as do all [[lepidoptera]]n larvae. They eat day and night, preferring [[White Mulberry]] but not being strictly [[monophagous]] they also take other species of ''[[Morus (plant)|Morus]]'' and some other [[Moraceae]]. Hatchlings and second-instar larvae are called '''kego''' (毛蚕, "hairy silkworm"<!-- "hairy baby" is incorrect - that would be 毛童 -->) in [[Japan]], or '''chawki''' in [[India]]. They are covered with little black hairs. When the color of their heads turns darker, it means that it is time for them to [[ecdysis|molt]]. Later instars are white, nude, 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 becomes tighter. The larvae enclose themselves in a [[Pupa#Cocoon|cocoon]] of raw silk produced in the [[salivary glands]] that provides protection during the vulnerable, almost motionless pupal state. Many other [[Lepidoptera]] produce cocoons, but only a few large [[Bombycidae]] and [[Saturniidae]] have been exploited for fabric production. {{main|Silk}} The cocoon is made of a single continuous thread of raw silk from 300 to 900 meters (1000 to 3000 feet) long. The fibers are very fine and lustrous, about 10 [[micrometers]] (1/2500th of an inch) in diameter. About 2,000 to 3,000 cocoons are required to make a pound of silk. Based on 1 kilometer (about 1100 yards) per cocoon, ten unraveled cocoons could theoretically extend vertically to the height of [[Mt Everest]]. At least 70 million pounds of raw silk are produced each year, requiring nearly 10 billion pounds of [[mulberry]] leaves. According to E. L. Palmer (Fieldbook of Natural History 1949), one pound of silk represents about 1,000 miles of filament. The annual world production represents 70 billion miles of silk filament, a distance well over 300 round trips to the sun. If the animal is allowed to survive after spinning its cocoon, it will release [[proteolytic]] [[enzyme]]s to make a hole in the cocoon so that it can emerge as a moth. This would cut short the [[yarn|threads]] and ruin the silk. Instead, silkworm cocoons are boiled. The heat kills the silkworms and the water makes the cocoons easier to unravel. Often, the silkworm itself is eaten (see also below). The adult phase (the moth) cannot fly. The silkmoths have a wingspan of 3-5 cm (1.5 - 2 inches) and a white hairy body. Females have about twice to three times the bulk of males (for they are carrying many eggs), but are similarly colored. Adults in the Bombycidae have reduced mouth parts and do not feed. ==Scientific and medical uses== Due to its large size and ease of culture, the silkworm has long been a [[model organism]] in the study of Lepidopteran and arthropod biology (Goldsmith ''et al.'' 2004). Fundamental findings on [[pheromone]]s, [[hormone]]s, brain structures and physiology were made with the silkworm (Grimaldi & Engel 2005). To characterize the first known pheromone, [[bombykol]], extracts were needed from 500,000 individuals because only very small quantities are produced (Scoble 1995). Currently, research is focusing on genetics of silkworms and genetic engineering. Many hundreds of strains are maintained, and over 400 [[Mendelian inheritance|Mendelian mutation]]s have been described (Goldsmith ''et al.'' 2004). One useful mutant for the silk industry confers the ability to feed on food besides mulberry leaves, including an artificial diet (Goldsmith ''et al.'' 2004). The genome has been sequenced (Mita ''et al.'' 2004), and many projects have worked on genetic engineering of silkworms to produce desirable proteins in the place of silk. Such proteins include human drugs (Grimaldi & Engel 2005). Silkworm is the source of the [[traditional Chinese medicine]] ''jiāngcán'' ("stiff silkworm", {{zh-st|s=僵蚕|t=僵蠶}}, trade name "Bombyx batryticatus"). It is the dried body of the 4-5th instar [[larva]] which has died of the [[white muscardine disease]]. Its uses are to dispel [[flatulence]], dissolve [[phlegm]] and relieve [[spasm]]s. ==Cuisine== Like many insect species, silkworm pupae are eaten in some cultures (see [[Entomophagy]]). In [[Korea]] they are boiled and seasoned to make a popular snack food known as ''[[beondegi]]''. In [[China]] street vendors sell roasted silkworm pupae. ==Silkworm legends== In China, there is a legend that the discovery of the silkworm's silk was by an ancient empress called [[Xi Ling-Shi]] ({{zh-cp|c=嫘祖|p=Léi Zǔ}}). She was drinking tea under a tree when a cocoon fell into her tea. She picked it out and as it started to wrap around her finger, she slowly felt a warm sensation. When the silk ran out, she saw a small cocoon. In an instant, she realized that this cocoon was the source of the silk. She taught this to the people and it became widespread. There are many more legends about the silkworm. The Chinese guarded their knowledge of silk. It is said that a Chinese monk smuggled silkworms, in a hollow stick, out of China and sold the secret to Europe, which was against the law and the punishment would be execution in the town square. ==Gallery== <gallery> Image:Bombyx mori 01.jpg|Females laying eggs Image:Bombyx mori Caterpillar 02.jpg|7-day (second instar) ''kego'' Image:BombyxMale.jpg|Male adult. Scale is 15 mm Image:BombyxFemelle.jpg|Female adult. Scale is 20 mm Image:Silkworms3000px.jpg|Fifth instar silkworm larvae, consuming [[Morus (plant)|mulberry]] leaves. Image:4thInstarLarvae3500px.jpg|Fifth instar silkworm larvae, clustered on a leaf. Image:Ipek-kozasi.jpg|Silkworm cocoons. Image:Silkwormmothtailorgan3500ppx.JPG|Silkworm moth female reproductive organ. Image:Silkwormmothemerging3800ppx.jpg|A silkworm moth just emerging from its cocoon. Image:FemaleSilkwormmoth3500ppx.jpg|A female silkworm moth perched on a cocoon. Image:Silkwormeggs3500ppx.jpg|Silkworm eggs laid on another cocoon. </gallery> ==See also== *[[Ginkgo biloba|Ginkgo]], another Chinese species not known to exist in an entirely wild state *[[History of silk|History of Silk]] *[[Silk Road]] ==References== * {{aut|Arunkumar, K.P.; Metta, Muralidhar & Nagaraju, J.}} (2006): Molecular phylogeny of silk moths reveals the origin of domesticated silkmoth, ''Bombyx mori'' from Chinese ''Bombyx mandarina'' and paternal inheritance of ''Antheraea proylei'' mitochondrial DNA. ''Molecular Phylogenetics and Evolution'' '''40'''(2): 419–427. <small>{{doi|10.1016/j.ympev.2006.02.023}}</small> (HTML abstract). [http://www.sciencedirect.com/cache/MiamiImageURL/B6WNH-4JTR94V-1-H/0?wchp=dGLbVzW-zSkWb Supplementary figure 1 (JPG)] [http://www.sciencedirect.com/cache/MiamiImageURL/B6WNH-4JTR94V-1-G/0?wchp=dGLbVzW-zSkWb Supplementary figure 2 (JPG)] [http://www.sciencedirect.com/cache/MiamiImageURL/B6WNH-4JTR94V-1-6/0?wchp=dGLbVzW-zSkWb Supplementary figure 3 (JPG)] * {{aut|Goldsmith, Marian R.; Shimada, Toru & Abe, Hiroaki}} (2004): The genetics and genomics of the silkworm, ''Bombyx mori''. ''[[Annual Reviews|Annu. Rev. Entomol.]]'' '''50''': 71-100. <small>PMID 15355234. {{doi|10.1146/annurev.ento.50.071803.130456}}</small> (HTML abstract) * {{aut|Grimaldi & Engel}} (2005): ''Evolution of the Insects''. Cambridge University Press. * {{aut|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. <small>{{doi|10.1007/BF00286912}}</small> (HTML abstract) * {{aut|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. <small>PMID 15141943. {{doi|10.1093/dnares/11.1.27}}</small> [http://dnaresearch.oxfordjournals.org/cgi/reprint/11/1/27.pdf PDF fulltext] * {{aut|Scoble, M.J.}} (1995): ''The Lepidoptera: Form, function and diversity''. Princeton University Press. * {{aut|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== {{Commons|Bombyx}} *[http://linus.socs.uts.edu.au/%7Edon/larvae/bomb/mori.html] Silkworms *[http://animaldiversity.ummz.umich.edu/site/accounts/information/Bombyx_mori.html] Student page on silkworm *[http://www.wormspit.com/index.htm WormSpit] A site about silkworms, silkmoths, and silk [[Category:Bombycidae]] [[Category:Insects as food]] [[Category:Silk]] [[af:Sywurm]] [[ar:دودة القز]] [[bg:Копринена буба]] [[ca:Cuc de seda]] [[cs:Bourec morušový]] [[de:Seidenspinner]] [[es:Bombyx mori]] [[eo:Silkraŭpo]] [[eu:Zetar]] [[fa:کرم ابریشم]] [[fr:Ver à soie]] [[ko:누에나방]] [[io:Silk-vermo]] [[id:Ulat sutra]] [[ia:Bombyx mori]] [[is:Silkiormur]] [[it:Bombyx mori]] [[he:טוואי המשי]] [[ka:თუთის აბრეშუმხვევია]] [[la:Bombyx]] [[lt:Šilkverpis]] [[hu:Selyemlepke]] [[ms:Ulat sutera]] [[nl:Zijdevlinder]] [[ja:カイコ]] [[no:Silkeorm]] [[nn:Silkeorm]] [[pl:Jedwabnik morwowy]] [[pt:Bicho-da-seda]] [[ru:Тутовый шелкопряд]] [[scn:Vermu dâ sita]] [[simple:Silkworm]] [[sl:Sviloprejka]] [[su:Hileud sutra]] [[fi:Mulperiperhonen]] [[sv:Silkesfjäril]] [[tr:İpek böceği]] [[zh:蚕]]