Katipo
Encyclopedia
Latrodectus katipo, the katipo, is an endangered species
of spider
native to New Zealand
. A member of the genus Latrodectus, it is related to the Australia
n redback spider, and the North America
n black widow spider
s. The species is venomous to humans, capable of delivering a comparatively dangerous spider bite
. 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. North of 39°15'S females do not have a red stripe and are all black. 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 coast
al New Zealand, but are not found at the 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 produces 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 19th 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, despite sightings being very rare.
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 relative is the Australia
n redback spider (Latrodectus hasseltii) Latrodectus katipo and L. atritus (black katipo) were previously thought to be two separate species, however, research has shown that there is only one species, L. katipo, and colour variation in that species is clinal over latitude and correlates significantly with mean annual temperature. The 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 hasseltii katipo. 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. 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.
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). This name was apparently given to the spider due to the Māori belief that the spiders bite at night. Other common name
s include red katipo, black katipo and New Zealand's redback.
, 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 spinnerets. 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. The red stripe is almost always absent in females north of 39°15'S.
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. Due to its much smaller size, Urquhart (1886) believed the male to be a separate species and named it Theridion melanozantha. This was not rectified until 1933 when it was correctly identified as the male Latrodectus katipo.
The katipo is restricted to a highly specialised habitat and is only found near the seashore living among sand dunes. 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.
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
). They may also build their webs under driftwood
, stones, or other debris such as empty tin can
s or bottles. Webs are almost always constructed over open sand and near the ground so as to catch crawling insects for food. 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. 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 kikuyu
or buffalo grass, create an environment unsuitable for web construction. 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.
Like other 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. The web consists of a broad base with many supporting threads above and below, including a number of sticky guy lines anchored to debris in the sand. A cone-shaped retreat is built in the lower part of the web, although the katipo can normally be found near the main body of the web. The plants it builds its web in provide support and shelter for the nest.
it is found along the West Coast from Wellington
to North Cape
. 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. This southern limit is due to the katipo needing temperatures higher than about 17 °C (62.6 °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.
s such as beetle
s (e.g. Cecyropa modesta) or amphipods
(e.g. Bellorchestia quoyana), but it may occasionally catch moth
s, flies
, and other spiders. 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 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 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. 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.
. 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. After mating, the male retreats to 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.
The females lay their eggs
in November or December. 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 millimetre (0.47244094488189 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. Over time the exterior of the egg sac may become covered with sand
. After six weeks of incubation, during January and February, the spiderlings hatch. The young spiders then disperse from the web. At present, little is known about the 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 maturity
the following spring.
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 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. There is evidence of interbreeding between katipo and redbacks in the wild.
from the family Ichneumonidae
has been observed feeding on katipo eggs.
and has recently become threatened with extinction
. 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. A number of reasons have contributed to its decline; the major factors appear to be loss of habitat
and declining quality of the remaining habitat. Human interference with their 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 beach buggies
, off road
vehicles, beach horse riding and driftwood collection have destroyed or changed areas where katipo lives. The introduction of many invasive exotic plants has also contributed to the decline of suitable habitat.
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
. 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 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. 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, 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’.
In June 2010 the katipo was given full protection under the Wildlife Act
to assist conservation efforts. Previously, it had no protection under the Act.
, 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 sometimes move offensively to bite any threat.
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. Most bites are caused by female spiders; the male katipo was considered too small to cause systemic envenoming in humans. 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. Māori legends recall many deaths, the last of which appears to have been a Māori girl who - according to the missionary Thomas Chapman - died in approximately 1849. While there were reports of severe katipo bites in 19th or early 20th century records, no other fatalities from spider bites have since been reported in New Zealand.
, nausea, vomiting, abdominal or chest pain
, generalised sweating, headache
, fever
, hypertension
and tremor
. Rare complications include seizure
, coma
, pulmonary edema
, respiratory failure
or localised skin infection. 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.
s. Patients should not apply pressure and should seek medical attention. In more severe bites, Redback antivenom can be given. Redback antivenom can also cross-neutralise katipo venom, and it is used to treat envenoming from Latrodectus katipo in New Zealand. It is available from most major New Zealand hospitals. 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. Particular indications for using antivenom are local then generalised pain, sweating or hypertension
. However, good evidence to support the effectiveness of widow spider antivenoms is lacking and studies have cast some doubt on antivenoms efficacy in latrodectism. Pain relief
agents, such as parenteral opiate
s, or benzodiazepine
s may be required as adjunct agents.
Endangered species
An endangered species is a population of organisms which is at risk of becoming extinct because it is either few in numbers, or threatened by changing environmental or predation parameters...
of spider
Spider
Spiders are air-breathing arthropods that have eight legs, and chelicerae with fangs that inject venom. They are the largest order of arachnids and rank seventh in total species diversity among all other groups of organisms...
native to New Zealand
New Zealand
New Zealand is an island country in the south-western Pacific Ocean comprising two main landmasses and numerous smaller islands. The country is situated some east of Australia across the Tasman Sea, and roughly south of the Pacific island nations of New Caledonia, Fiji, and Tonga...
. A member of the genus Latrodectus, it is related to the Australia
Australia
Australia , officially the Commonwealth of Australia, is a country in the Southern Hemisphere comprising the mainland of the Australian continent, the island of Tasmania, and numerous smaller islands in the Indian and Pacific Oceans. It is the world's sixth-largest country by total area...
n redback spider, and the North America
North America
North America is a continent wholly within the Northern Hemisphere and almost wholly within the Western Hemisphere. It is also considered a northern subcontinent of the Americas...
n black widow spider
Black widow spider
Latrodectus mactans, the Southern black widow, is a highly venomous species of spider in the genus Latrodectus. They are well known for the distinctive black and red coloring of the female of the species and for the fact that she will occasionally eat her mate after reproduction. The species is...
s. The species is venomous to humans, capable of delivering a comparatively dangerous spider bite
Spider bite
A spider bite is an injury resulting from the bites of spiders or other closely related arachnids.Spiders are active hunters and rely heavily on their bites to paralyze and kill their prey before consuming it. They also bite in self defense...
. Katipo is a Māori
Maori language
Māori or te reo Māori , commonly te reo , is the language of the indigenous population of New Zealand, the Māori. It has the status of an official language in New Zealand...
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. North of 39°15'S females do not have a red stripe and are all black. 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
Habitat
* Habitat , a place where a species lives and grows*Human habitat, a place where humans live, work or play** Space habitat, a space station intended as a permanent settlement...
, being only found living in sand dunes close to the seashore. They range throughout most of coast
Coast
A coastline or seashore is the area where land meets the sea or ocean. A precise line that can be called a coastline cannot be determined due to the dynamic nature of tides. The term "coastal zone" can be used instead, which is a spatial zone where interaction of the sea and land processes occurs...
al New Zealand, but are not found at the southernmost regions. Spinning an irregular tangled web amongst dune plants or other debris, they feed mainly on ground dwelling insect
Insect
Insects are a class of living creatures within the arthropods that have a chitinous exoskeleton, a three-part body , three pairs of jointed legs, compound eyes, and two antennae...
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
Extinction
In biology and ecology, extinction is the end of an organism or of a group of organisms , normally a species. The moment of extinction is generally considered to be the death of the last individual of the species, although the capacity to breed and recover may have been lost before this point...
.
A bite
Bite
A bite is a wound received from the mouth of an animal, including humans.Animals may bite in self-defense, in an attempt to predate food, as well as part of normal interactions. Other bite attacks may be apparently unprovoked. Self inflicted bites occur in some genetic illnesses such as...
from the katipo produces a toxic syndrome known as latrodectism
Latrodectism
Latrodectism is the clinical syndrome caused by the neurotoxic venom , that can be injected by the bite of any spider that is a member of the spider genus Latrodectus, in the family Theridiidae....
. Symptoms include extreme pain
Pain
Pain is an unpleasant sensation often caused by intense or damaging stimuli such as stubbing a toe, burning a finger, putting iodine on a cut, and bumping the "funny bone."...
and potentially systemic effects, such as hypertension
Hypertension
Hypertension or high blood pressure is a cardiac chronic medical condition in which the systemic arterial blood pressure is elevated. What that means is that the heart is having to work harder than it should to pump the blood around the body. Blood pressure involves two measurements, systolic and...
, seizure
Seizure
An epileptic seizure, occasionally referred to as a fit, is defined as a transient symptom of "abnormal excessive or synchronous neuronal activity in the brain". The outward effect can be as dramatic as a wild thrashing movement or as mild as a brief loss of awareness...
, or coma
Coma
In medicine, a coma is a state of unconsciousness, lasting more than 6 hours in which a person cannot be awakened, fails to respond normally to painful stimuli, light or sound, lacks a normal sleep-wake cycle and does not initiate voluntary actions. A person in a state of coma is described as...
. Bites are rare and deaths have not been reported since the 19th 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, despite sightings being very rare.
Taxonomy
Although the 'kātĕpo' was reported to the Linnean Society as early as 1855, the katipo was formally described as Latrodectus katipo by L. Powell in 1870. Spiders of the genus Latrodectus have a worldwide distribution and include all of the commonly known widow spiderWidow spider
Latrodectus is a genus of spider, in the family Theridiidae, which contains 31 recognized species. The common name widow spiders is sometimes applied to members of the genus due to the behavior of the female of eating the male after mating, although sometimes the males of some species are not eaten...
s, namely the North America
North America
North America is a continent wholly within the Northern Hemisphere and almost wholly within the Western Hemisphere. It is also considered a northern subcontinent of the Americas...
n black widow spider (Latrodectus mactans), the brown widow (Latrodectus geometricus
Latrodectus geometricus
The spider Latrodectus geometricus, commonly known as the brown widow, grey widow, or geometric button spider, is one of the widow spiders in the genus Latrodectus. As such, it is a "cousin" to the more famous Latrodectus mactans...
) and the European black widow (Latrodectus tredecimguttatus
Latrodectus tredecimguttatus
Latrodectus tredecimguttatus, commonly known as the Mediterranean black widow or steppe spider, is a species of widow spiders in the genus Latrodectus. It is commonly found throughout the Mediterranean region, ranging from Spain to southwest and central Asia, hence the name...
). The katipo's closest relative is the Australia
Australia
Australia , officially the Commonwealth of Australia, is a country in the Southern Hemisphere comprising the mainland of the Australian continent, the island of Tasmania, and numerous smaller islands in the Indian and Pacific Oceans. It is the world's sixth-largest country by total area...
n redback spider (Latrodectus hasseltii) Latrodectus katipo and L. atritus (black katipo) were previously thought to be two separate species, however, research has shown that there is only one species, L. katipo, and colour variation in that species is clinal over latitude and correlates significantly with mean annual temperature. The 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 hasseltii katipo. 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. The katipo's family Theridiidae
Theridiidae
Theridiidae is a large family of spiders, also known as the tangle-web spiders, cobweb spiders and comb-footed spiders. The diverse family includes over 2200 species in over 100 genera) of three-dimensional space-web-builders found throughout the world...
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.
The common name, katipo, is a Māori
Maori language
Māori or te reo Māori , commonly te reo , is the language of the indigenous population of New Zealand, the Māori. It has the status of an official language in New Zealand...
name and means night stinger; it is derived from two words, kakati (to sting), and po (the night). This name was apparently given to the spider due to the Māori belief that the spiders bite at night. Other common name
Common name
A common name of a taxon or organism is a name in general use within a community; it is often contrasted with the scientific name for the same organism...
s include red katipo, black katipo and New Zealand's redback.
Description
The katipo is a small to medium-sized spider. The mature female has a body size of about 8 millimetre (0.31496062992126 in) with a leg span of up to 32 millimetres (1.3 in). It has a large black globular abdomenAbdomen
In vertebrates such as mammals the abdomen constitutes the part of the body between the thorax and pelvis. The region enclosed by the abdomen is termed the abdominal cavity...
, about the size of a garden pea
Pea
A pea is most commonly the small spherical seed or the seed-pod of the pod fruit Pisum sativum. Each pod contains several peas. Peapods are botanically a fruit, since they contain seeds developed from the ovary of a flower. However, peas are considered to be a vegetable in cooking...
, 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 spinnerets. 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
Hourglass
An hourglass measures the passage of a few minutes or an hour of time. It has two connected vertical glass bulbs allowing a regulated trickle of material from the top to the bottom. Once the top bulb is empty, it can be inverted to begin timing again. The name hourglass comes from historically...
-shaped marking. It has mainly black legs with the extremities changing to brown. The red stripe is almost always absent in females north of 39°15'S.
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
Carapace
A carapace is a dorsal section of the exoskeleton or shell in a number of animal groups, including arthropods such as crustaceans and arachnids, as well as vertebrates such as turtles and tortoises. In turtles and tortoises, the underside is called the plastron.-Crustaceans:In crustaceans, the...
, 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. Due to its much smaller size, Urquhart (1886) believed the male to be a separate species and named it Theridion melanozantha. This was not rectified until 1933 when it was correctly identified as the male Latrodectus katipo.
Habitat
Storm
A storm is any disturbed state of an astronomical body's atmosphere, especially affecting its surface, and strongly implying severe weather...
s and sand movement. They can sometimes be associated with dunes several kilometres from the sea when these dunes extend inland for long distances.
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
Ammophila arenaria
Ammophila arenaria is a species of grass known by the common names European Marram Grass and European Beachgrass. It is one of two species of the genus Ammophila . It is native to the coastlines of Europe and North Africa where it grows in the sands of beach dunes. It is a perennial grass forming...
). They may also build their webs under driftwood
Driftwood
Driftwood is wood that has been washed onto a shore or beach of a sea or river by the action of winds, tides, waves or man. It is a form of marine debris or tidewrack....
, stones, or other debris such as empty tin can
Tin can
A tin can, tin , steel can, or a can, is a sealed container for the distribution or storage of goods, composed of thin metal. Many cans require opening by cutting the "end" open; others have removable covers. Cans hold diverse contents: foods, beverages, oil, chemicals, etc."Tin" cans are made...
s or bottles. Webs are almost always constructed over open sand and near the ground so as to catch crawling insects for food. 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. 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 kikuyu
Pennisetum clandestinum
The tropical grass species Pennisetum clandestinum is known by several common names, most often kikuyu grass, as it is native to the region of East Africa that is home to the Kĩkũyũ tribe. Because of its rapid growth and aggressive nature, it is categorised as a noxious weed in some regions...
or buffalo grass, create an environment unsuitable for web construction. 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.
Like other theridiid
Tangle web spider
Theridiidae is a large family of spiders, also known as the tangle-web spiders, cobweb spiders and comb-footed spiders. The diverse family includes over 2200 species in over 100 genera) of three-dimensional space-web-builders found throughout the world...
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. The web consists of a broad base with many supporting threads above and below, including a number of sticky guy lines anchored to debris in the sand. A cone-shaped retreat is built in the lower part of the web, although the katipo can normally be found near the main body of the web. The plants it builds its web in provide support and shelter for the nest.
Range
The katipo is endemic to New Zealand. In the North IslandNorth Island
The North Island is one of the two main islands of New Zealand, separated from the much less populous South Island by Cook Strait. The island is in area, making it the world's 14th-largest island...
it is found along the West Coast from Wellington
Wellington
Wellington is the capital city and third most populous urban area of New Zealand, although it is likely to have surpassed Christchurch due to the exodus following the Canterbury Earthquake. It is at the southwestern tip of the North Island, between Cook Strait and the Rimutaka Range...
to North Cape
North Cape, New Zealand
North Cape is located at the northern end of the North Auckland Peninsula in the North Island of New Zealand . It is the northeastern tip of the Aupouri Peninsula and lies 30 km east of Cape Reinga. The name is sometimes used to refer just to the cape which is known in Māori as Otou and which...
. On the east coast of the North Island it occurs irregularly, however, it is abundant on Great Barrier Island
Great Barrier Island
Great Barrier Island is a large island of New Zealand, situated to the north-east of central Auckland in the outer Hauraki Gulf. With an area of it is the fourth-largest island of New Zealand's main chain of islands, with its highest point, Mount Hobson, rising...
. In the South Island
South Island
The South Island is the larger of the two major islands of New Zealand, the other being the more populous North Island. It is bordered to the north by Cook Strait, to the west by the Tasman Sea, to the south and east by the Pacific Ocean...
it is found in coastal regions south to Dunedin
Dunedin
Dunedin is the second-largest city in the South Island of New Zealand, and the principal city of the Otago Region. It is considered to be one of the four main urban centres of New Zealand for historic, cultural, and geographic reasons. Dunedin was the largest city by territorial land area until...
on the east coast and south to Greymouth
Greymouth
Greymouth is the largest town in the West Coast region in the South Island of New Zealand, and the seat of the Grey District Council. The population of the whole Grey District is , which accounts for % of the West Coast's inhabitants...
on the west coast. This southern limit is due to the katipo needing temperatures higher than about 17 °C (62.6 °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.
Diet
The katipo typically catches wandering ground invertebrateInvertebrate
An invertebrate is an animal without a backbone. The group includes 97% of all animal species – all animals except those in the chordate subphylum Vertebrata .Invertebrates form a paraphyletic group...
s such as beetle
Beetle
Coleoptera is an order of insects commonly called beetles. The word "coleoptera" is from the Greek , koleos, "sheath"; and , pteron, "wing", thus "sheathed wing". Coleoptera contains more species than any other order, constituting almost 25% of all known life-forms...
s (e.g. Cecyropa modesta) or amphipods
Amphipoda
Amphipoda is an order of malacostracan crustaceans with no carapace and generally with laterally compressed bodies. The name amphipoda means "different-footed", and refers to the different forms of appendages, unlike isopods, where all the legs are alike. Of the 7,000 species, 5,500 are classified...
(e.g. Bellorchestia quoyana), but it may occasionally catch moth
Moth
A moth is an insect closely related to the butterfly, both being of the order Lepidoptera. Moths form the majority of this order; there are thought to be 150,000 to 250,000 different species of moth , with thousands of species yet to be described...
s, flies
Fließ
Fließ is a municipality in the Landeck district and is located5 km south of Landeck on the upper course of the Inn River. It has 9 hamlets and was already populated at the roman age; the village itself was founded around the 6th century. After a conflagration in 1933 Fließ was restored more...
, and other spiders. 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 silks
Spider silk
Spider silk is a protein fiber spun by spiders. Spiders use their silk to make webs or other structures, which function as nets to catch other animals, or as nests or cocoons for protection for their offspring...
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 tarsi
Tarsus (skeleton)
In tetrapods, the tarsus is a cluster of articulating bones in each foot situated between the lower end of tibia and fibula of the lower leg and the metatarsus. In the foot the tarsus articulates with the bones of the metatarsus, which in turn articulate with the bones of the individual toes...
of the hind legs have a row of strong curved bristles which are arranged as a comb
Comb
A comb is a toothed device used in hair care for straightening and cleaning hair or other fibres. Combs are among the oldest tools found by archaeologists...
. The katipo uses these to scoop sticky silk from her spinnerets and throws it over the insect with a series of rapid movements. 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.
Reproduction
The male wanders as an adult and in August or September goes looking for the females' webs to mateMating
In biology, mating is the pairing of opposite-sex or hermaphroditic organisms for copulation. In social animals, it also includes the raising of their offspring. Copulation is the union of the sex organs of two sexually reproducing animals for insemination and subsequent internal fertilization...
. 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. After mating, the male retreats to groom
Personal grooming
Personal grooming is the art of cleaning, grooming, and maintaining parts of the body. It is a species-typical behavior that is controlled by neural circuits in the brain.- In humans :...
, 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
Widow spider
Latrodectus is a genus of spider, in the family Theridiidae, which contains 31 recognized species. The common name widow spiders is sometimes applied to members of the genus due to the behavior of the female of eating the male after mating, although sometimes the males of some species are not eaten...
s.
The females lay their eggs
Egg (biology)
An egg is an organic vessel in which an embryo first begins to develop. In most birds, reptiles, insects, molluscs, fish, and monotremes, an egg is the zygote, resulting from fertilization of the ovum, which is expelled from the body and permitted to develop outside the body until the developing...
in November or December. The eggs are round, about the size of a mustard seed
Mustard seed
Mustard seeds are the small round seeds of various mustard plants. The seeds are usually about 1 or 2 mm in diameter. Mustard seeds may be colored from yellowish white to black. They are important spices in many regional foods. The seeds can come from three different plants: black mustard , brown...
, and are a transparent, purply red. They are held together in a cream-coloured, round, ball shaped egg sac which is about 12 millimetre (0.47244094488189 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. Over time the exterior of the egg sac may become covered with sand
Sand
Sand is a naturally occurring granular material composed of finely divided rock and mineral particles.The composition of sand is highly variable, depending on the local rock sources and conditions, but the most common constituent of sand in inland continental settings and non-tropical coastal...
. After six weeks of incubation, during January and February, the spiderlings hatch. The young spiders then disperse from the web. At present, little is known about the dispersal
Biological dispersal
Biological dispersal refers to species movement away from an existing population or away from the parent organism. Through simply moving from one habitat patch to another, the dispersal of an individual has consequences not only for individual fitness, but also for population dynamics, population...
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 maturity
Sexual maturity
Sexual maturity is the age or stage when an organism can reproduce. It is sometimes considered synonymous with adulthood, though the two are distinct...
the following spring.
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 offspring
Offspring
In biology, offspring is the product of reproduction, of a new organism produced by one or more parents.Collective offspring may be known as a brood or progeny in a more general way...
. 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. There is evidence of interbreeding between katipo and redbacks in the wild.
Predators
The katipo has only one known direct predator: a small, undescribed native waspWasp
The term wasp is typically defined as any insect of the order Hymenoptera and suborder Apocrita that is neither a bee nor an ant. Almost every pest insect species has at least one wasp species that preys upon it or parasitizes it, making wasps critically important in natural control of their...
from the family Ichneumonidae
Ichneumonidae
Ichneumonidae is a family within the insect order Hymenoptera. Insects in this family are commonly called ichneumon wasps. Less exact terms are ichneumon flies , or scorpion wasps due to the extreme lengthening and curving of the abdomen...
has been observed feeding on katipo eggs.
Population decline
The katipo is an endangered speciesEndangered species
An endangered species is a population of organisms which is at risk of becoming extinct because it is either few in numbers, or threatened by changing environmental or predation parameters...
and has recently become threatened with extinction
Extinction
In biology and ecology, extinction is the end of an organism or of a group of organisms , normally a species. The moment of extinction is generally considered to be the death of the last individual of the species, although the capacity to breed and recover may have been lost before this point...
. 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. A number of reasons have contributed to its decline; the major factors appear to be loss of habitat
Habitat destruction
Habitat destruction is the process in which natural habitat is rendered functionally unable to support the species present. In this process, the organisms that previously used the site are displaced or destroyed, reducing biodiversity. Habitat destruction by human activity mainly for the purpose of...
and declining quality of the remaining habitat. Human interference with their natural habitat
Habitat (ecology)
A habitat is an ecological or environmental area that is inhabited by a particular species of animal, plant or other type of organism...
has been occurring for over a century following European settlement. Coastal dune modification resulting from agriculture
Agriculture
Agriculture is the cultivation of animals, plants, fungi and other life forms for food, fiber, and other products used to sustain life. Agriculture was the key implement in the rise of sedentary human civilization, whereby farming of domesticated species created food surpluses that nurtured the...
, forestry
Forestry
Forestry is the interdisciplinary profession embracing the science, art, and craft of creating, managing, using, and conserving forests and associated resources in a sustainable manner to meet desired goals, needs, and values for human benefit. Forestry is practiced in plantations and natural stands...
, or urban development along with recreational activities like the use of beach buggies
Dune buggy
A dune buggy is a recreational vehicle with large wheels, and wide tires, designed for use on sand dunes or beaches. The design is usually a modified vehicle and engine mounted on an open chassis. The modifications usually attempt to increase the power-to-weight ratio by either lightening the...
, off road
Off-roading
Off-roading is a term for driving a vehicle on unsurfaced roads or tracks, made of materials such as sand, gravel, riverbeds, mud, snow, rocks, and other natural terrain.-Off-road vehicle:...
vehicles, beach horse riding and driftwood collection have destroyed or changed areas where katipo lives. The introduction of many invasive exotic plants has also contributed to the decline of suitable habitat.
South Africa
The Republic of South Africa is a country in southern Africa. Located at the southern tip of Africa, it is divided into nine provinces, with of coastline on the Atlantic and Indian oceans...
n spider Steatoda capensis
Steatoda capensis
Steatoda capensis is a spider originating from South Africa. Its common names include the black cobweb spider, brown house spider, cupboard spider and due to its similarities to the katipo spider it is commonly known as the false katipo in New Zealand...
. It was first reported in the 1990s and may have displaced the katipo along the west coast of the North Island from Wellington
Wellington
Wellington is the capital city and third most populous urban area of New Zealand, although it is likely to have surpassed Christchurch due to the exodus following the Canterbury Earthquake. It is at the southwestern tip of the North Island, between Cook Strait and the Rimutaka Range...
to Wanganui
Wanganui
Whanganui , also spelled Wanganui, is an urban area and district on the west coast of the North Island of New Zealand. It is part of the Manawatu-Wanganui region....
. 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 recolonise
Colonisation (biology)
Colonisation is the process in biology by which a species spreads into new areas, regions, and continents. It is sometimes also referred to as immigration, but colonisation often refers to successful immigration with integration to a community, having resisted initial local extinction.One classic...
areas from which the katipo had been displaced after storm
Storm
A storm is any disturbed state of an astronomical body's atmosphere, especially affecting its surface, and strongly implying severe weather...
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. S. capensis also belongs to the family Theridiidae
Theridiidae
Theridiidae is a large family of spiders, also known as the tangle-web spiders, cobweb spiders and comb-footed spiders. The diverse family includes over 2200 species in over 100 genera) of three-dimensional space-web-builders found throughout the world...
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, 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’.
In June 2010 the katipo was given full protection under the Wildlife Act
Wildlife Act 1953
-External links:*...
to assist conservation efforts. Previously, it had no protection under the Act.
Toxicology
The katipo has medically significant venom in humans, although bites are rare. The incidence of bites is low as it is a shyShyness
In humans, shyness is a social psychology term used to describe the feeling of apprehension, lack of comfort, or awkwardness experienced when a person is in proximity to, approaching, or being approached by other people, especially in new situations or with unfamiliar people...
, 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 sometimes move offensively to bite any threat.
Bites from Katipo spiders produce a syndrome known as latrodectism
Latrodectism
Latrodectism is the clinical syndrome caused by the neurotoxic venom , that can be injected by the bite of any spider that is a member of the spider genus Latrodectus, in the family Theridiidae....
. The venom
Venom
Venom is the general term referring to any variety of toxins used by certain types of animals that inject it into their victims by the means of a bite or a sting...
s of all Latrodectus spiders are thought to contain similar components with the neurotoxin
Neurotoxin
A neurotoxin is a toxin that acts specifically on nerve cells , usually by interacting with membrane proteins such as ion channels. Some sources are more general, and define the effect of neurotoxins as occurring at nerve tissue...
α-latrotoxin
Latrotoxin
A latrotoxin is a high-molecular mass neurotoxin found in the venom of spiders of the genus Latrodectus . Latrotoxin are the main active components of the venom and are responsible for the symptoms of latrodectism....
the main agent responsible. Most bites are caused by female spiders; the male katipo was considered too small to cause systemic envenoming in humans. 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. Māori legends recall many deaths, the last of which appears to have been a Māori girl who - according to the missionary Thomas Chapman - died in approximately 1849. While there were reports of severe katipo bites in 19th or early 20th century records, no other fatalities from spider bites have since been reported in New Zealand.
Symptoms
The clinical features of latrodectism are similar for all species of Latrodectus spiders and is generally characterised by extreme pain. 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 proximally from the site. Less commonly, systemic envenoming is heralded by swollen or tender regional lymph nodes; associated features include malaiseMalaise
Malaise is a feeling of general discomfort or uneasiness, of being "out of sorts", often the first indication of an infection or other disease. Malaise is often defined in medicinal research as a "general feeling of being unwell"...
, nausea, vomiting, abdominal or chest pain
Chest pain
Chest pain may be a symptom of a number of serious conditions and is generally considered a medical emergency. Even though it may be determined that the pain is non-cardiac in origin, this is often a diagnosis of exclusion made after ruling out more serious causes of the pain.-Differential...
, generalised sweating, headache
Headache
A headache or cephalalgia is pain anywhere in the region of the head or neck. It can be a symptom of a number of different conditions of the head and neck. The brain tissue itself is not sensitive to pain because it lacks pain receptors. Rather, the pain is caused by disturbance of the...
, fever
Fever
Fever is a common medical sign characterized by an elevation of temperature above the normal range of due to an increase in the body temperature regulatory set-point. This increase in set-point triggers increased muscle tone and shivering.As a person's temperature increases, there is, in...
, hypertension
Hypertension
Hypertension or high blood pressure is a cardiac chronic medical condition in which the systemic arterial blood pressure is elevated. What that means is that the heart is having to work harder than it should to pump the blood around the body. Blood pressure involves two measurements, systolic and...
and tremor
Tremor
A tremor is an involuntary, somewhat rhythmic, muscle contraction and relaxation involving to-and-fro movements of one or more body parts. It is the most common of all involuntary movements and can affect the hands, arms, eyes, face, head, vocal folds, trunk, and legs. Most tremors occur in the...
. Rare complications include seizure
Seizure
An epileptic seizure, occasionally referred to as a fit, is defined as a transient symptom of "abnormal excessive or synchronous neuronal activity in the brain". The outward effect can be as dramatic as a wild thrashing movement or as mild as a brief loss of awareness...
, coma
Coma
In medicine, a coma is a state of unconsciousness, lasting more than 6 hours in which a person cannot be awakened, fails to respond normally to painful stimuli, light or sound, lacks a normal sleep-wake cycle and does not initiate voluntary actions. A person in a state of coma is described as...
, pulmonary edema
Pulmonary edema
Pulmonary edema , or oedema , is fluid accumulation in the air spaces and parenchyma of the lungs. It leads to impaired gas exchange and may cause respiratory failure...
, respiratory failure
Respiratory failure
The term respiratory failure, in medicine, is used to describe inadequate gas exchange by the respiratory system, with the result that arterial oxygen and/or carbon dioxide levels cannot be maintained within their normal ranges. A drop in blood oxygenation is known as hypoxemia; a rise in arterial...
or localised skin infection. 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.
Treatment
Treatment consists of observation in a medical facility for six hours from the time of the bite. Patients with localised pain, swelling and redness usually do not require any specific treatment apart from applying ice and routine analgesicAnalgesic
An analgesic is any member of the group of drugs used to relieve pain . The word analgesic derives from Greek an- and algos ....
s. Patients should not apply pressure and should seek medical attention. In more severe bites, Redback antivenom can be given. Redback antivenom can also cross-neutralise katipo venom, and it is used to treat envenoming from Latrodectus katipo in New Zealand. It is available from most major New Zealand hospitals. 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. Particular indications for using antivenom are local then generalised pain, sweating or hypertension
Hypertension
Hypertension or high blood pressure is a cardiac chronic medical condition in which the systemic arterial blood pressure is elevated. What that means is that the heart is having to work harder than it should to pump the blood around the body. Blood pressure involves two measurements, systolic and...
. However, good evidence to support the effectiveness of widow spider antivenoms is lacking and studies have cast some doubt on antivenoms efficacy in latrodectism. Pain relief
Pain management
Pain management is a branch of medicine employing an interdisciplinary approach for easing the suffering and improving the quality of life of those living with pain. The typical pain management team includes medical practitioners, clinical psychologists, physiotherapists, occupational therapists,...
agents, such as parenteral opiate
Opiate
In medicine, the term opiate describes any of the narcotic opioid alkaloids found as natural products in the opium poppy plant.-Overview:Opiates are so named because they are constituents or derivatives of constituents found in opium, which is processed from the latex sap of the opium poppy,...
s, or benzodiazepine
Benzodiazepine
A benzodiazepine is a psychoactive drug whose core chemical structure is the fusion of a benzene ring and a diazepine ring...
s may be required as adjunct agents.