T.E.R:R.A.I.N - Taranaki Educational Resource: Research, Analysis and Information Network


Katipo spider (Latrodectus katipo)

Kingdom: Animalia
Phylum: Arthropoda
Class: Arachnida|
Order: Araneae
Family: Theridiidae
Genus: Latrodectus (includes the Black widow and Redback spiders.)
Species: L. katipo
Binomial name: Latrodectus katipo
Synonyms: Latrodectus atritus, Latrodectus hasseltii atritus, Latrodectus katipo atritus, Theridium melanozantha, Theridium zebrinia
Common name: Katipo is a Māori name and means "night-stinger".

Latrodectus katipo is an endangered species, endemic to New Zealand. Due to a steady population decline, katipo is now classified as Absolutely Protected under the Wildlife Act. It 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 storms and sand movement. They can sometimes be associated with dunes several kilometres from the sea when these dunes extend inland for long distances. Its habitat is grasses, sedges, driftwood, and flotsam.
There are two forms of katipo. There is a black form that is found in the northern half of the North Island and a red-striped form that is found further south with its southern limit on the Otago coast. On the South Island's West Coast it occurs from Greymouth north.
The adult female of katipo of the red form is a small, dark, velvet-coloured spider with a body size of about 8 millimetres with a leg span of up to 32 millimetres and is characterised by its large globular abdomen (about the size of a pea) with an orange or red stripe down the middle. It may sometimes have white markings both at the front of the abdomen and also bordering a pronounced red stripe. This stripe starts in the middle of the abdomen and runs towards the rear end of the spider. There is also a red hourglass shape on the underside of the abdomen.

The spider's black form lacks the red stripe but is otherwise similar in size and appearance. This black form was previously known as Latrodectus atritus but both the red stripe and black forms are now regarded as the same species.
Variations also exist whose abdomen, cephalothorax, or entire body is brown, sometimes with a dull red or yellow stripe, or cream-coloured spots on its upper side.

Males are of a much smaller in size, being about one sixth the size of an adult female. Males and juveniles of both forms have a lot of white that gives way to black as the spiders moult. Males go through fewer moults than females and they never attain the females' size or dark colour. Indeed, they still look very much like juveniles despite being fully grown.

Latrodectus katipo spin irregular tangled webs amongst dune plants or other debris, they feed mainly on ground dwelling insects. 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.

Katipo bites are very uncommon, and while likely to be unpleasant, are not likely to prove lethal. A bite produces a toxic syndrome known as latrodectism. The symptoms include extreme pain and potentially systemic effects, such as hypertension, seizure, or coma. Treatment is based on the severity of the bite; the majority of cases do not require medical care and patients with localised pain, swelling and redness usually only require local application of ice and routine analgesics. Hospital assessment is recommended if simple analgesia does not resolve local pain or clinical features of systemic envenoming occur. An antivenin is available in New Zealand for treatment. The very few fatal cases reported are based on rather dubious records from the 1800s.

Thanks to Wikipedia, Te Papa the Museum of New Zealand, Te Ara Encyclopedia of New Zealand for the above information

Lab-reared female Latrodectus katipo
 

A beach Katapo
 

The distribution of katipo spiders. The black form, the black's variations and the red form.