Katipo
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2008-06-30T20:58:08Z
Mr Bungle
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{{Taxobox
| name = Katipo spider
| image = Latrodectus katipo.jpg
| image_width = 250px
| image_caption = Female Katipo spider
| status = EN
| regnum = [[Animal]]ia
| phylum = [[Arthropoda]]
| classis = [[Arachnida]]
| ordo = [[Spider|Araneae]]
| familia = [[Theridiidae]]
| genus = '''''[[Latrodectus]]'''''
| species = '''''L. katipo'''''
| binomial = ''Latrodectus katipo''
| binomial_authority = Powell, 1870
}}
The '''katipo''' or '''red katipo''' (''Latrodectus katipo'') is an [[Endangered species|endangered]], [[spiders having medically significant venom|venomous spider]] native to [[New Zealand]]. It is a [[widow spider]] and is related to the [[black katipo]], the [[Australia]]n [[redback spider]], and the [[North America]]n [[black widow spider]]s. Katipo is a [[Māori]] name and means "night-stinger". It is a small to medium-sized spider with the female having a distinctive black body with a white bordered red stripe on its back. The male is much smaller than the female and quite different in appearance, being white with black stripes and red diamond shaped markings. Katipo have a narrow habitat, being only found living in sand dunes close to the seashore. They range throughout most of coastal New Zealand, but are not found at the northern or southernmost regions. Spinning an irregular tangled web amongst dune plants or other debris, they feed mainly on ground dwelling [[insect]]s.
After mating in August or September, the female produces five or six egg sacs in November or December. The spiderlings hatch during January and February and disperse into surrounding plants. Due to the loss of habitat and colonisation of their natural habitat by other exotic spiders, the katipo is being faced with extinction.
A [[bite]] from the katipo is [[poison]]ous to humans producing a toxic syndrome known as [[latrodectism]]. Symptoms include extreme [[pain]] and potentially systemic effects, such as [[hypertension]], [[seizure]], or [[coma]]. Bites are rare and deaths have not been reported since the 18th century. An [[antivenom]] is available in New Zealand for treatment. The katipo is particularly notable in New Zealand as the nation is almost entirely devoid of dangerous native wildlife. This unique status has led to the spider becoming well-known,<ref name="Sutton">{{cite web | title =Field identification of katipo (DOC Research & Development Series 237) | author= Sutton ME, Christensen B, Hutcheson JA |publisher = Department of Conservation, Wellington, New Zealand | date = April 2006 | url =http://www.doc.govt.nz/upload/documents/science-and-technical/drds237.pdf| format = | doi = | accessdate = 2008-05-26}}</ref> despite sightings being very rare.<ref name="Collins">{{cite web | title =Katipo now rarer than the kiwi | author= Simon Collins |publisher = New Zealand Herald| date = January 14 2005 | url =http://www.nzherald.co.nz/section/1/story.cfm?c_id=1&objectid=10006517 | format = | doi = | accessdate = 2008-05-27}}</ref>
==Taxonomy==
The katipo was formally described as ''Latrodectus katipo'' by L. Powell in 1870.<ref name="powell">{{cite journal | author = Powell Ll | title = On Latrodectus (Katipo), the Poisonous Spider of New Zealand | journal = Transactions and Proceedings of the Royal Society of New Zealand 1868-1961 | volume = 3 | issue = | pages = 56–9 | year = 1870 | pmid = | url = http://rsnz.natlib.govt.nz/volume/rsnz_03/rsnz_03_00_002380.pdf }}</ref> Spiders of the genus ''[[Latrodectus]]'' have a worldwide distribution and include all of the commonly known [[widow spider]]s, namely the [[North America]]n black widow spider (''[[Latrodectus mactans]]''), the brown widow (''[[Latrodectus geometricus]]'') and the European black widow (''[[Latrodectus tredecimguttatus]]''). The katipo's closest relatives are the New Zealand [[Indigenous (ecology)|native]] black katipo (''[[Latrodectus atritus]]'') and the [[Australia]]n redback spider (''[[Latrodectus hasselti]]''). The katipo and black katipo are so closely related to the redback that they were at one stage thought to be a subspecies. It was proposed that the katipo be named ''Latrodectus hasselti hasselti'' and the black katipo ''Latrodectus hasselti atritus''. Further research has shown that the katipo is distinct from the redback, having slight structural differences and striking differences in habitat preference, and it remains its own species.<ref name="Forster-Kingsford"/><ref name="Forster2"/>
The katipo's family [[Theridiidae]] has a large number of species both in New Zealand and worldwide and are commonly known as tangle-web spiders, cobweb spiders or comb-footed spiders.<ref name="Patrick">{{cite web | title =Conservation status of the New Zealand red katipo spider (Latrodectus katipo Powell, 1871)| author= Patrick B |publisher = New Zealand Department of Conservation | date = April 2002 | url =http://www.doc.govt.nz/upload/documents/science-and-technical/sfc194.pdf | format = | doi = | accessdate = 2008-05-26}}</ref>
The common name, katipo, is a [[Māori]] name and means night stinger; it is derived from two words, ''kakati'' (to sting), and ''po'' (the night).<ref name="Nature1873">{{cite journal | author = Anonymous | title = The katipo or poisonous spider of New Zealand | journal = [[Nature (journal)|Nature]] | volume = 7 | issue = 159 | pages = 29 | year = 1872 |pmid = | doi =10.1038/007029c0}}</ref> This name was apparently given to the spider due to the Māori belief that the spiders bite at night.<ref name="NZMJ1951-hornabrook"/> Other [[common name]]s include red katipo and New Zealand’s redback.<ref name="Riordan">{{cite web | title =Species Profile: Katipo spider | author= Hilary Ann Riordan |publisher = CanterburyNature| date = July 2005 | url =http://www.canterburynature.org/species/lincoln_essays/katipo.php| format = | doi = | accessdate = 2008-05-27}}</ref>
==Description==
The katipo is a small to medium-sized spider.<ref name="Landcare-Research"/> The mature female has a body size of about 8 mm (0.31 in) with a leg span of up to 32 mm (1.26 in). It has a large black globular [[abdomen]], about the size of a garden [[pea]], with slender legs and a white-bordered orange or red stripe on its back that runs from the uppermost surface of the abdomen back to the [[spinneret]]s. The dark velvet-black abdomen is described as satin or silky in appearance, rather than being shiny. The underside of the abdomen is black and has a red patch or partial red [[hourglass]]-shaped marking. It has mainly black legs with the extremities changing to brown.<ref name="Sutton"/><ref name="Forster2">{{cite book | last = Forster | first = Ray | coauthors = Forster, Lyn | authorlink = | title = New Zealand Spiders: An Introduction | publisher = Collins Brothers & Co Ltd| location = Auckland | date = 1973 | pages = 225-35| doi = | isbn = }}</ref><ref name="Forster">{{cite book | last = Forster | first = Ray | coauthors = Forster, Lyn | authorlink = | title = Spiders Of New Zealand And Their Worlwide Kin | publisher = University Of Otago Press | location = Dunedin | date = 1999 | pages = 173-7 | doi = | isbn = 1-877133-79-5}}</ref><ref name="Buller">{{cite journal | author = Buller W | title = On the Katipo, or Venomous Spider of New Zealand | journal = Transactions and Proceedings of the Royal Society of New Zealand 1868-1961 | volume = 3 | issue = | pages = 29–34 | year = 1870 | pmid = | url = http://rsnz.natlib.govt.nz/volume/rsnz_03/rsnz_03_00_002310.pdf}}</ref><ref name="Griffiths">{{cite web | title =Katipo threatened by changes to coastal sand dunes | author= James Griffiths |publisher = Royal Forest and Bird Protection Society of New Zealand | date = 2008 | url=http://www.forestandbird.org.nz/publications/magazine/2002/november/katipo.asp| format = | doi = | accessdate = 2008-05-26}}</ref><ref>{{cite web | title =Katipo Spider | author= Roy Alexander Harrison |publisher = The encyclopedia of New Zealand | date = | url =http://www.teara.govt.nz/1966/K/KatipoSpider/KatipoSpider/en| format = | doi = | accessdate = 2008-05-26}}</ref>
Adult males and juveniles are quite different in appearance to the female. They are smaller in size, being about one sixth the size of an adult female. Juveniles have a brown [[carapace]], with a predominantly white abdomen which has a series of red-orange diamonds running along the dorsal region bordered on either side by irregular black lines. Males retain this coloration into adulthood.<ref name="Forster2"/><ref name="Griffiths"/><ref name="McCutcheon"/><ref name="NZNPC">{{cite web | title =Spiders in New Zealand | author= |publisher = The New Zealand National Poisons Centre| date = | url =http://www.poisons.co.nz/files.php?f=8| format = | doi = | accessdate = 2008-05-26}}</ref> Due to its much smaller size, Urquhart (1886) believed the male to be a separate species and named it ''Theridion melanozantha''.<ref>{{cite journal |author=Urquhart AT|title=On New Species of Araneidea |journal=Transactions and Proceedings of the New Zealand Institute |volume=19 |issue= |pages=72–118 |year=1886 |month= |pmid= |doi= |url=http://rsnz.natlib.govt.nz/volume/rsnz_19/rsnz_19_00_002350.html}}</ref> This was not rectified until 1933 when it was correctly identified as the male ''Latrodectus katipo''.<ref name="Forster-Kingsford">{{cite journal |author=Forster L, Kingsford S |title=Preliminary study of development in two Latrodectus species (Araneae:Theridiidae) |journal=New Zealand Entomologist |volume=7 |issue=4 |pages=431–39 |year=1983 |month=|pmid= |doi= |url=http://www.ento.org.nz/nzentomologist/free_issues/NZEnto07_4_1983/Volume%207-4-431-439.pdf}}</ref>
==Habitat==
[[Image:Beach katipo.jpg|left|thumb|A katipo under a piece of [[driftwood]].]]
The katipo is restricted to a highly specialised habitat and is only found near the seashore living among [[sand dune]]s. They generally reside on the landward side of dunes closest to the coast where they are most sheltered from [[storm]]s and sand movement. They can sometimes be associated with dunes several kilometres from the sea when these dunes extend inland for long distances.<ref name="Patrick"/>
Webs are typically established in low-growing dune plants and other vegetation such as the native pingao (''[[Desmoschoenus spiralis]]'') or the introduced marram grass (''[[Ammophila arenaria]]'').<ref name="Riordan"/> They may also build their webs under [[driftwood]], stones, or other debris such as empty [[tin can]]s or bottles.<ref name="Landcare-Research">{{cite web | title =What is this bug? A guide to common invertebrates of New Zealand | author= Clunie L |publisher = Landcare Research New Zealand | date = 2004 | url=http://www.landcareresearch.co.nz/research/biosystematics/invertebrates/invertid/bug_details.asp?Bu_ID=55 | format = | doi = | accessdate = 2008-05-26}}</ref><ref name="NZNPC"/> Webs are almost always constructed over open sand and near the ground so as to catch crawling insects for food.<ref name="Forster"/> Spiders inhabiting dune grasses construct their webs in open spaces between the grass tufts, while spiders inhabiting areas of shrubbery do so on the underside of a plant overhanging open sand.<ref name="Griffiths"/> It has been found that these patches of open sand are necessary for katipo to build their webs as plants that envelop sand dunes in dense cover, such as exotic plants like [[Pennisetum clandestinum|kikuyu]] or buffalo grass, create an environment unsuitable for web construction.<ref name="Griffiths"/> The katipo therefore prefers to spin its web amongst pingao plants as this plants growth pattern leaves patches of sand between each plant. The wind can then blow insects and other prey through these gaps and into the web. Marram grass has been extensively planted in New Zealand to help stabilise sand dunes and has largely replaced pingao in many areas. Because marram grass grows in a very tight formation only leaving small gaps between tuffs, this makes it difficult for the katipo to construct a suitable web for capturing prey.<ref name="Forster"/><ref name="Riordan"/>
Like other [[Tangle web spider|theridiid]] spiders, the web is a disorganised, irregular tangle of fine textured silk. It is hammock-shaped and is made up of opaque yellowish-white silk.<ref name="Buller"/> The web consists of a broad base with many supporting threads above and below, including a number of sticky [[guy line]]s anchored to debris in the sand. A cone-shaped retreat is built in the lower part of the web,<ref name="Forster"/> although the katipo can normally be found near the main body of the web.<ref name="Riordan"/> The plants it builds its web in provide support and shelter for the nest.<ref name="Forster"/>
==Range==
The katipo is [[endemism|endemic]] to New Zealand.<ref name="Riordan"/> In the [[North Island]] it is found along the West Coast from [[Wellington]] to north of [[Wanganui]], [[New Plymouth]] and [[Waitara, New Zealand|Waitara]]. It is rare or extinct in the north of the North Island. On the east coast of the North Island it occurs irregularly, however it is abundant on [[Great Barrier Island]]. In the [[South Island]] it is found in coastal regions south to [[Dunedin]] on the east coast and south to [[Greymouth]] on the west coast.<ref name="Patrick"/><ref name="McCutcheon">{{cite journal |author=McCutcheon ER |title=Distribution of the katipo spiders (Araneae: Theridiidae) of New Zealand |journal=NZ Entomol |volume=6 |issue=2 |pages=204 |year=1976 | url=http://www.ento.org.nz/nzentomologist/free_issues/NZEnto06_2_1976/Volume%206-2-204.pdf | pmid=}}</ref> This southern limit is due to the katipo needing temperatures higher than about 17° [[Celsius|C]] (63° [[Fahrenheit|F]]) to be maintained during the development of their eggs, explaining why they are not found in the southern areas of New Zealand where it is typically colder than this.<ref name="Forster"/>
==Behavior==
===Diet===
The katipo typically catches wandering ground [[invertebrate]]s such as [[beetle]]s (e.g. ''Cecyropa modesta'') or [[Amphipods]] (e.g. ''[[Talorchestia quoyana]]''), but it may occasionally catch [[moth]]s, [[flies]], and other spiders.<ref name="Riordan"/><ref name="Forster"/><ref name="Crowe">{{cite book| last = Crowe | first = Andrew | authorlink = | title = Which New Zealand Spider? | publisher = Penguin Books | location = Auckland | date = 2007 | pages = 20 | doi = | isbn = 9780143006435 }}</ref> Katipo can catch insects much larger than themselves. These larger insects often become entangled in the web and in the ensuing struggle, the web's ground anchor line breaks. Due to the [[Spider silk|silks]] elasticity, this causes the prey to become suspended a few centimetres off the ground. The katipo then moves to the prey, turns so that the spinnerets are facing the insect and spins silk over it. Like most theridiids, the [[Tarsus (skeleton)|tarsi]] of the hind legs have a row of strong curved bristles which are arranged as a [[comb]]. The katipo uses these to scoop sticky silk from her spinnerets and throws it over the insect with a series of rapid movements.<ref name="Forster2"/> After the insect is firmly immobilised, she bites it several times, usually at the joints, before spinning more silk to strengthen the web, and then administering a last long bite which ultimately kills the insect. The spider then moves the prey up into the web until it is ready to eat. If food is readily available then it is common to see five or six insects hanging in the web waiting to be ingested. The male's hunting behaviour is similar to the female's, although may not be as vigorous due to its smaller size.<ref name="Forster"/>
===Reproduction===
The male wanders as an adult and in August or September goes looking for the females' webs to [[Mating|mate]]. The male will enter the female's web and vibrate the silk as he approaches her. The female is usually aggressive at first and will chase the male from the web. The Courtship process consists of the male bobbing, plucking and tweaking the web along with periods of cautious approach and being chased by the female. Eventually, when she becomes docile and allows him to approach, the male will then approach the female as she hangs quietly upside down in the web. The male moves onto her [[ventral]] abdomen, tapping her rapidly until she moves to align his abdomen above hers. He then inserts his [[palps]] one at a time, leaving the female between each insertion. [[Copulation]] occurs over 10 to 30 minutes.<ref name="Forster"/> After mating, the male retreats to [[Personal grooming|groom]], which is performed by running his palps and legs through his fangs and wiping them over his body. The male is not eaten by the female unlike some other [[widow spider]]s.<ref name="Forster"/>
The females lay their [[Egg (biology)|eggs]] in November or December.<ref name="Riordan"/> The eggs are round, about the size of a [[mustard seed]], and are a transparent, purply red. They are held together in a cream-coloured, round, ball shaped [[egg sac]] which is about 12 mm (0.47 in) in diameter. The female constructs five or six egg sacs over the next three to four weeks. Each egg sac contains about 70 to 90 fertilised eggs. The egg sacs are hung in the centre of the spiders web and the female spins more silk over them.<ref name="Riordan"/><ref name="Forster"/> Over time the exterior of the egg sac may become covered with [[sand]].<ref name="Nature1873"/> After six weeks of incubation, during January and February, the spiderlings hatch.<ref name="Riordan"/> The young spiders then disperse from the web. At present, little is known about the [[Biological dispersal|dispersal]] mechanism that the spiderlings use to move away from the nest. In one study, observing spiders over 24 hours, 28% used a ballooning method, which is where the young spiders use heat currents to carry themselves away from the nest suspended by a single web strand. While the majority, 61%, used a bridging method where the spiderling uses its silk to move to nearby plants, and 11% still remained in the nest. The young spiderlings reach full [[Sexual maturity|maturity]] the following spring.<ref name="Riordan"/>
The close relationship between the katipo and redback is shown when mating, The male redback is able to successfully mate with a female katipo producing [[Hybrid (biology)|hybrid]] [[offspring]]. However, the male katipo can not mate with the female redback as the male katipo is heavier than the male redback and when it approaches the web it triggers a [[predatory]] response in the female leading to the katipo being eaten before mating occurs.<ref name="Riordan"/> In areas where their habitats overlap, the [[black katipo]] does not [[interbreed]] with the katipo. Laboratory studies have confirmed that the katipo and black katipo do not generally interbreed and if they do, the resulting eggs are infertile.<ref name="Forster"/>
==Predators==
The katipo has only one known direct [[predator]]. A small, undescribed native [[wasp]] from the family [[Ichneumonidae]] has been observed feeding on katipo eggs.<ref name="Patrick"/>
==Population decline==
The katipo is an [[endangered species]] and has recently become threatened with [[extinction]].<ref name="Riordan"/> It is estimated that there are only a few thousand katipo left in about 50 areas in the North Island and eight in the South Island.<ref>{{cite web | title =It's poisonous, but it's ours - DoC seeks aid for spider | author= Simon Collins |publisher = New Zealand Herald| date = January 14 2005 | url =http://www.nzherald.co.nz/section/story.cfm?c_id=39&objectid=10006530 | format = | doi = | accessdate = 2008-06-08}}</ref> A number of reasons have contributed to its decline; the major factors appear to be [[Habitat destruction|loss of habitat]] and declining quality of the remaining habitat.<ref name="Patrick"/> Human interference with their [[Habitat (ecology)|natural habitat]] has been occurring for over a century following European settlement. Coastal dune modification resulting from [[agriculture]], [[forestry]], or [[urban development]] along with recreational activities like the use of [[Dune buggy|beach buggies]], [[Off-roading|off road]] vehicles, beach [[horse riding]] and driftwood collection have destroyed or changed areas where katipo lives.<ref name="Patrick"/><ref name="Griffiths"/><ref>{{cite web | title =The Life Around Us: Enter amazing world of NZ's spiders | author= Virgil Evetts |publisher = New Zealand Herald| date = January 11 2008 | url =http://www.nzherald.co.nz/section/story.cfm?c_id=82&objectid=10486206&pnum=0 | format = | doi = | accessdate = 2008-06-08}}</ref> The introduction of many invasive exotic plants has also contributed to the decline of suitable habitat.<ref name="Griffiths"/>
[[Image:Steatoda capensis.jpg|rightt|thumb|''[[Steatoda capensis]]'', the false katipo spider.]] Foreign spiders have colonised areas where suitable habitat remains. The major coloniser is the [[South Africa]]n spider ''[[Steatoda capensis]]''. It was first reported in the 1990s and may have displaced the katipo along the west coast of the North Island from [[Wellington]] to [[Wanganui]].<ref name="Collins"/><ref name="Riordan"/> Although both the katipo and ''S. capensis'' have been found sharing the same dune systems or even co-existing under the same piece of driftwood suggesting that the two species can co-exist in similar habitats. It is possible that the displacement of the katipo by ''S. capensis'' is due to its ability to [[Colonisation (biology)|recolonise]] areas from which the katipo had been displaced after [[storm]]s or other dune modifications. Furthermore ''S. capensis'' breeds year-round, produces more offspring and lives in a greater range of habitats which leads to greater pressure on the katipo.<ref name="Patrick"/> ''S. capensis'' also belongs to the family [[Theridiidae]] and shares many of the katipo's features. It is of similar size, shape, general coloration, it lacks the red stripe on its back, but may have some red, orange or yellow on its abdomen,<ref name="Griffiths"/> as well as the general location where katipos are found. Due to these similarities it is commonly known in New Zealand as the ‘false katipo’.<ref name="Sutton"/>
==Toxicology==
{{main|Latrodectism}}
The katipo has [[spiders having medically significant venom|medically significant venom]] in humans, although bites are rare.<ref name="NZNPC"/> The incidence of bites is low as it is a [[shyness|shy]], non-aggressive spider. Their narrow range, diminishing population, and human awareness of where they live means interaction between humans and the spider is minimal. The katipo will only bite as a last resort; if molested, the spider will usually fold up into a ball and drop to the ground or retreat to the nearest cover. If the threat continues, the spider may throw out silk against the interference. When restrained in any way or held against skin, such as if tangled up in clothing, the spider will then bite defensively. However, if the female is with an egg sac it will remain close by it and sometime move offensively to bite any threat.<ref name="NZMJ1951-hornabrook"/>
Bites from Katipo spiders produce a syndrome known as [[latrodectism]]. The [[venom]]s of all ''Latrodectus'' spiders are thought to contain similar components with the [[neurotoxin]] α-[[latrotoxin]] the main agent responsible.<ref>{{cite journal |author=Nicholson GM, Graudins A, Wilson HI, Little M, Broady KW |title=Arachnid toxinology in Australia: from clinical toxicology to potential applications |journal=Toxicon |volume=48 |issue=7 |pages=872–98 |year=2006 |month=December |pmid=16934848 |doi=10.1016/j.toxicon.2006.07.025 |url=}}</ref><ref name="Graudins"/> Most bites are caused by female spiders; the male katipo was considered too small to cause systemic envenoming in humans.<ref name="NZMJ1951-hornabrook"/> However, bites from male redback spiders have been reported suggesting male ''Latrodectus'' spiders can cause envenoming in humans. Although bites by male spiders are much rarer than those by females, perhaps due to their smaller jaws rather than lacking venom of similar potency to females or being unable to administer an effective bite.<ref name="isbister"/> Māori legends recall many deaths and there were reports of severe katipo bites in 19th or early 20th century records, however, the only two reported fatalities were recorded in the 18th century.<ref name="NZMJ1951-hornabrook">{{cite journal | author = Hornabrook R | title = Studies in preventive hygiene from the Otago Medical School: the katipo spider | journal = [[N Z Med J]] | volume = 50 | issue = 276 | pages = 131–8 | year = 1951 | pmid = 14853159}}</ref> No other fatalities from spider bites have ever been reported in New Zealand.<ref name=" O'Donnell ">{{cite journal | author = O'Donnell M | title = A review of records of spider bites on humans in New Zealand including some previously unpublished records| journal = The Weta | volume = 6 | issue = 2 | pages = 72–4 | year = 1983 | pmid = |url=http://www.ento.org.nz/nzentomologist/free_issues/Weta06_2_1983/Weta6(2)_72_74.pdf}}</ref>
===Symptoms===
The clinical features of latrodectism are similar for all species of ''Latrodectus'' spiders and is generally characterised by extreme pain.<ref name="NZMJ1951-hornabrook"/><ref name="isbister"/> Initially, the bite may be painful, but sometimes only feels like a pin prick or mild burning sensation. Within an hour victims generally develop more severe local pain with local sweating and sometimes [[piloerection]] (goosebumps). Pain, swelling and redness spread [[proximal]]ly from the site. Less commonly, systemic envenoming is heralded by swollen or tender regional [[lymph nodes]]; associated features include [[malaise]], nausea, vomiting, abdominal or [[chest pain]], generalised sweating, [[headache]], [[fever]], [[hypertension]] and [[tremor]].<ref name="isbister">{{cite journal |author=Isbister G, Gray M |title=Latrodectism: a prospective cohort study of bites by formally identified Redback spiders |journal=Med J Aust |volume=179 |issue=2 |pages=88–91 |year=2003 |pmid=12864719}}</ref><ref name="White">{{cite book | editor = Meier J, White J | title = Handbook of clinical toxicology of animal venoms and poisons | year = 1995 | publisher = CRC Press | pages = 284-302 | id = ISBN 0-8493-4489-1}}</ref> Rare complications include [[seizure]], [[coma]], [[pulmonary edema]], [[respiratory failure]] or localised skin infection.<ref name="sutherland">{{cite journal |author=Sutherland S, Trinca J |title=Survey of 2144 cases of Redback spider bites: Australia and New Zealand, 1963--1976 |journal=Med J Aust |volume=2 |issue=14 |pages=620–3 |year=1978 |pmid=732670}}</ref> The duration of effects can range from a few hours to days, with severe pain persisting for over 24 hours after being bitten in some cases.<ref name="isbister/gray">{{cite journal |author=Isbister GK, Gray MR |title=A prospective study of 750 definite spider bites, with expert spider identification |journal=QJM |volume=95 |issue=11 |pages=723–31 |year=2002 |month=November |pmid=12391384 |doi= 10.1093/qjmed/95.11.723|url=http://qjmed.oxfordjournals.org/cgi/pmidlookup?view=long&pmid=12391384}}</ref><ref name="Vetter"/>
===Treatment===
Treatment consists of observation in a medical facility for six hours from the time of the bite.<ref name="White"/> Patients with localised pain, swelling and redness usually do not require any specific treatment apart from applying ice and routine [[analgesic]]s. In more severe bites, Redback [[antivenom]] is routinely given. Redback antivenom can also cross-neutralise katipo venom,<ref>{{cite journal |author=Wiener S |title=Red back spider antivenene |journal=[[The Medical Journal of Australia|Med J Aust]] |volume=48 |issue= 2 |pages=41–4 |year=1961 |month=July |pmid=13785109 |doi= |url=}}</ref> and it is used to treat envenoming from ''Latrodectus katipo'' in New Zealand.<ref name="Graudins">{{cite journal |author=Graudins A, Padula M, Broady K, Nicholson GM |title=Red-back spider (Latrodectus hasselti) antivenom prevents the toxicity of widow spider venoms |journal=[[Annals of Emergency Medicine|Ann Emerg Med]] |volume=37 |issue=2 |pages=154–60 |year=2001 |month=February |pmid=11174232 |doi=10.1067/mem.2001.113033 |url=}}</ref> It is available from most major New Zealand hospitals.<ref name="Landcare-Research"/> Antivenom will usually relieve symptoms of systemic envenoming and is indicated in anyone suffering symptoms consistent with ''Latrodectus'' envenoming. Unlike some other antivenoms, it is not limited to patients with signs of severe, systemic envenoming.<ref name="Graudins"/> Particular indications for using antivenom are local then generalised pain, sweating or [[hypertension]].<ref name="CSL">{{cite book | last = White | first = Julian | authorlink = | title = CSL antivenom handbook | publisher = CSL Ltd | location = Melbourne | date = 2001 | pages = 52-4 | doi = | isbn = 0-646-26814-7}}</ref> However, good evidence to support the effectiveness of widow spider antivenoms is lacking and studies have cast some doubt on antivenoms efficacy in latrodectism.<ref name="isbister"/> [[Pain management|Pain relief]] agents, such as parenteral [[opiate]]s, may be required as adjunct agents.<ref name="Vetter">{{cite journal |author=Vetter RS, Isbister GK|title=Medical aspects of spider bites |journal=Annu Rev Entomol |volume=53 |issue= |pages=409–29 |year=2008 |month= |pmid=17877450 |doi= 10.1146/annurev.ento.53.103106.093503|url=}}</ref>
==References==
{{reflist}}
[[Category:Latrodectus]]
[[Category:Spiders of New Zealand]]
[[fr:Latrodectus katipo]]
[[nl:Katipo]]
[[pl:Katipo]]