Nematomorpha 43196 225660386 2008-07-14T19:54:12Z XLinkBot 6163802 BOT--Reverting edits by [[:en:Special:Contributions/88.104.222.237|88.104.222.237]] to revision 219717827 (\byoutube\.com) {{Taxobox | name = Nematomorpha | image = Paragordius tricuspidatus.jpeg | image_width = 250px | caption = ''[[Paragordius tricuspidatus]]'' | domain = ''[[Eukaryota]]'' | regnum = [[Animal]]ia | phylum = '''Nematomorpha''' | phylum_authority = [[Vejdovsky]], 1886 | subdivision_ranks = [[Class (biology)|Classes]] | subdivision = [[Nectonematoida]]<br/>[[Gordioidea]] }} '''Nematomorpha''' (sometimes called '''Gordiacea''', and commonly known as '''Horsehair worms''' or '''Gordian worms''') are a [[phylum]] of [[parasitic]] [[animal]]s which are [[morphology (biology)|morphologically]] and [[ecology|ecologically]] similar to [[nematode]] worms, hence the name. They are, on average, 1&nbsp;[[meter]] long, and 1 to 3&nbsp;[[millimetre]]s in diameter. Horsehair worms can be discovered in damp areas such as watering troughs, streams, puddles, and cisterns. The adult worms are free living, but the [[larva]]e are [[parasite|parasitic]] on [[beetle]]s, [[cockroach]]es, [[grasshopper]]s and [[crustacean]]s. About 320 species have been described. Nematomorphs possess an external [[cuticle]] without [[cilia]]. Internally, they have only longitudinal muscle and a non-functional gut, with no [[excretory system|excretory]], [[respiratory system|respiratory]] or [[circulatory system]]s. Reproductively, they are [[dioecious]], with the internal fertilization of eggs that are then laid in gelatinous strings. Nematomorphs can be confused with nematodes, particularly Mermithid worms. Unlike Nematomorphs, Mermithids do not have a terminal cloaca. Male mermithids have one or two spicules just before the end apart from having a thinner, smoother cuticle, without areoles and a paler brown colour.<ref>Malcolm S. Bryant, Robert D. Adlard & Lester R.G. Cannon 2006. Gordian Worms: Factsheet. Queensland Museum. [http://www.qm.qld.gov.au/inquiry/factsheets/Gordian_Worms_20070605.pdf]</ref> [[Image:Spinochordodes in Meconema.jpg|thumb|250px|left|''[[Spinochordodes tellinii]]'' and its katydid host]] In ''[[Spinochordodes tellinii]]'', which has grasshoppers as its [[vector (biology)|vector]], the infection acts on the grasshopper's brain and causes it to seek water and drown itself, thus returning the nematomorph to water.<ref>{{cite journal |quotes=no | last = Thomas | first = F. | coauthors = Schmidt-Rhaesa, A., Martin, G., Manu, C., Durand, P., and Renaud, F. | year = 2002 | month = May | title = Do hairworms (Nematomorpha) manipulate the water seeking behaviour of their terrestrial hosts? | journal = [[Journal of evolutionary biology|J. Evol. Biol.]] | volume = 15 | issue = 3 | pages = 356–361 | id = {{ISSN|1010-061X}} |url=http://www.erin.utoronto.ca/~w3gwynne/BIO418/Nemato.pdf | doi = 10.1046/j.1420-9101.2002.00410.x}} — according to Thomas ''et al.'', the "infected insects may first display an erratic behaviour which brings them sooner or later close to a stream and then a behavioural change that makes them enter the water", rather than seeking out water over long distances.</ref> They are also remarkably able to survive the predation of their host, being able to wriggle out of the predator which has eaten the host cricket.<ref>{{cite journal |quotes=no | last = Ponton | first = Fleur | coauthors = Camille Lebarbenchon, Thierry Lefèvre, David G. Biron, David Duneau, David P. Hughes, and Frédéric Thomas | year = 2006 | month = April | title = Parasitology: Parasite survives predation on its host | journal = [[Nature (journal)|Nature]] | volume = 440 | issue = 7085 | page = 756 | doi = 10.1038/440756a | pages = 756}}</ref> Relationships within the phylum are still somewhat unclear, but two classes are recognised: *Class [[Nectonematoida]]: Marine, planktonic, with a double row of natotory [[seta]]e along each side of the body; with dorsal and ventral longitudinal epidermal cords, [[blastocoelom]] spacious and fluid filled; [[gonad]]s single; larvae parasitise [[Decapoda|decapod crustaceans]] *Class [[Gordioidea]]: Freshwater and semiterrestrial; lack lateral rows of setae; with a single, ventral epidermal cord; blastocoelom filled with [[mesenchyme]] in young animals but becomes spacious in older individuals; larvae parasitise grasshoppers and [[cricket]]s ==References== {{reflist}} ==External links== *[http://www.canal.ird.fr/canal.php?url=/programmes/recherches/grillons_us/index.htm The cricket suicide (video)] * [http://www.nature.com/nature/journal/v440/n7085/suppinfo/440756a.html Videos of a cricket infected with a Gordian worm] with the worm emerging to mate, as well as emerging from predators which have eaten the infected cricket. From ''[[Nature (journal)|Nature]]'', April 2006. * [http://www.youtube.com/watch?v=xu9bqt2OgFM YouTube video of worms crawling out of a crushed grasshopper.] [[Category:parasitic animals]][[Category:Psuedocoelomates]] {{Link FA|de}} [[ca:Nematomorf]] [[cs:Strunovci]] [[de:Saitenwürmer]] [[et:Jõhvussid]] [[es:Nematomorpha]] [[fr:Nematomorpha]] [[gl:Nematomorpha]] [[ko:유선형동물]] [[it:Nematomorpha]] [[ka:ბეწვურები]] [[nl:Nematomorpha]] [[ja:類線形動物]] [[nn:Taglmakk]] [[no:Taglormer]] [[pl:Nitnikowce]] [[pt:Nematomorpha]] [[ru:Волосатики]] [[sk:Strunovce (okrúhlovce)]] [[sr:Nematomorpha]] [[fi:Jouhimadot]] [[tr:Kılımsısolucanlar]] [[zh:线形虫动物门]]