Latrodectus katipo
Written by Hilary Ann Riordan (Lincoln University)
July 2005
Edited by Michael Hudson, Lincoln University, September 2006
Taxonomy
- Scientific name: Latrodectus katipo (Powell, 1871)
- Popular Common names: Katipo spider
- Other common names: red katipo, New Zealand’s red back, night stinger
- Kingdom: Animalia
- Phylum: Arthropoda
- Class: Arachnida (the spider, mites, scorpions, and relatives)
- Order: Araneae (the spiders)
- Family: Theridiidae (the cobweb spiders)
- New Zealand Status: native (endemic)
- Taxonomy sources: Patrick (2002), Forster& Forster (1973) and Griffiths (2002).
Identification
Species Description
As adults the female and male katipo spider (Lactrodectus katipo) differ in appearance. The female katipo is 6mm in length (Forster, 1967) with an abdomen of similar size to that of a garden pea. The black abdomen is shiny and round with a red stripe down the top surface (Figure 1). A small red patch is sometimes located on the underside of the abdomen (Forster& Forster, 1973). The male katipo is much smaller at only 4 mm in length. The predominantly white abdomen has a central black band with three black streaks on either side. Also two irregular black bands on the top enclose a string of orange diamond shaped patches (Figure 2). The male katipo retains the same markings as those shared by the adolescent female and male. The female changes colour as it grows to the adult stage (Forster& Forster, 1973).
Some rights reserved, Jon Sullivan (Fig. 1,3) and Jill McCaw (Fig. 2)
Figures 1–3. Katipo spiders at Kaitorete Spit, Canterbury. (Click on an image for the full caption.)
Similar species
The Australian red-back spider (Latrodectus hasselti) is the katipo’s closest relative. The red-back is regarded as endemic to Australia. It contains a red hour glass shaped marking on the under side of the abdomen with a bright red stripe on top. Just below the thorax sits a separate, red, diamond-shaped marking on the top of the abdomen; just below this sits a solid red band flowing length ways down to the tail (Kai, 1981). The katipo is commonly confused with the black katipo (Latrodectus atritus). The black katipo is similar in size but the red stripe is absent and an indistinctive hourglass marking is present on the underside of the abdomen (Forster & Forster, 1999). The black katipo is only found in the Northern third of New Zealand (Patrick, 2002).
Geographic Distribution
Full natural and naturalised range
The katipo is only found in New Zealand (Patrick, 2002). However, the family Theridiidae is found all over the world, and their ancestors possibly evolved on Pangea (Griffiths, 2002).
New Zealand range
The katipos origins in New Zealand are unknown. Forster believes that the spiders have possibly been here since the splitting of Gondwana; whereas Griffiths suggest that they could possibly have colonised more recently (Griffiths, 2002). Small clusters of katipo populations are found along coast lines as far south as Karamea and Dunedin, and as far north as New Plymouth and the East Cape (Griffiths, 2002).
Canterbury range
Only found on the coast the katipo natural range in Canterbury stretches along the coast line from Leithfield Beach down to Kaitorete Spit. The katipo numbers are highest at Kaitorete Spit; this is also where the sand dunes have been the least modified (Griffiths, 2002).
Natural History in Canterbury
Habitats
Living amongst the coastal sand dunes the katipo inhabit areas close to the sea (Figure 3). Webs are created in amongst grasses such as New Zealand’s native pingao (Desmoschoenus spiralis) and the exotic marram grass (Ammophila arenaria). The marram grass does not provide preferred habitat for the katipo as the growth pattern is too close together. Katipo also create webs on driftwood and in amongst rubbish, such as old tin cans, which people leave on the beach (Patrick, 2002).
Preferred habitats
Katipos live in a very restricted habitat near the sea, usually where the beach is sandy (Forster & Forster, 1973). In addition katipo are also found where coastal sand dunes change into land (Patrick, 2002). Katipos prefer to inhabit areas of pingao, this plant allow their webs to be made close to the ground because of the growth pattern. Pingao leave patches of sand between each plant. Through these gaps the wind can blow insects in to the webs (Griffiths, 2002).
Because of human development to sand dunes the katipo’s habitat has been disturbed. To help retain sand dunes coastal plants such as marram grass were introduced to New Zealand. Marram grass is a very invasive species; it grows in a very tight formation leaving very small gaps between tufts. This formation prevents the katipo from constructing their hammock shaped webs (Griffiths, 2002). Without being able to construct their webs they are unable to catch sufficient food to eat.
Human activities such as off road vehicles and driftwood removal are also affecting the katipo population (Griffiths, 2002). In addition development of sand dunes for housing is shrinking the size of their habitat.
Phenology/Breeding
Forster & Forster (1999) say that mating may occur over half an hour; whereas Griffiths (2002) recalls it taking between 10 to 15 minutes. After copulation the male katipo retreats to groom and is rarely eaten (Forster& Forster, 1999). The egg sacs appear during November and December. The female creates one to three egg sacs and lays about 70 to 90 fertilised eggs in each sac (Griffiths, 2002). The cream egg sacs are round and about 12 millimetres in diameter. The female then hangs the sacs in a bunch in the body of the web and spins more silk over them (Forster& Forster, 1973). During January and February, after six weeks of incubation, the spiderlings emerge (Griffiths, 2002). Griffiths observed that the spiderlings take approximately 30 days to emerge at 15-25 degrees. Young katipo spiderlings reach full maturity the following spring (Forster& Forster, 1973).
The close relation of the katipo to the L. hasselti is shown when mating. The male L. hasselti may mate with a female katipo and produce first generation hybrids. The male katipo does not successfully mate with a female L. hasselti. The male katipo is much heavier than the male L. hasselti, therefore it triggers a predatory response in the female L. hasselti and is eaten (Griffiths, 2002).
Dispersal
Currently little is known about the dispersal mechanism used by the katipo spiders (Griffiths, 2002). Griffiths research looked at two commonly used dispersal methods: spiderling dispersal and water borne dispersal. It was discovered that from the total of 36 observed spiderlings: 28% used a ballooning method (when the spiderlings use heat currents to carry themselves away from the nest suspended by a single web strand); 61% used a bridging method (where they use their silk to move away from the nest); and after 24 hours 11% still remained on the Marram grass.
For the water borne dispersal method only one female katipo survived a maximum of 14 days while most other females died in the first two days. Griffiths (2002) concluded that spiders contain the right physiological attributes that could promote large distance dispersal. This can therefore explain “why geographical barriers such as headlands, estuaries and areas of open sea not appear to restrict their distribution” (Griffiths, 2002, page?).
Diet
The diet of the katipo mostly consists of live invertebrates such as coleopterans (e.g. the weevil Cecyropa modesta) and isopodan (e.g. Talorchestia quoyana) (Smith, 1971 cited in Griffiths, 2002). Katipo are able to catch beetles much larger than themselves in their webs. They then inject the beetle with poison, before sucking out the fluids leaving only the hard exoskeleton of the beetle (Forster& Forster, 1973).
Behaviour
The entangled webs of the katipo are constructed close to the ground with only a few sticky threads. Mostly located at the base of a tuft of marram grass or sedge, the webs can also be found on driftwood and rubbish (Forster& Forster, 1973). Unlike other species of Latrodectus that build a retreat, in which the spider remains until it has caught some food, the katipo is normally found near the main body of its web (Forster& Forster, 1973). The smaller male katipo spider does not bite (Forster& Forster, 1999). As mentioned previously, contrary to common belief, after mating occurs the male is seldom killed by the female (Forster & Forster, 1973).
Competitors
The South African spider Steatod capnsis may be displacing the katipo in some areas. The S. capensis is found in many dunes that were historically abundant with katipos (Griffiths, 2002). The S. capensis is able to breed twice as many times as the katipo; late spring and early summer (Hann, 1990: sited in Griffiths, 2002). Griffiths personally observed that the S. capensis has less specific habitat requirements then the katipo.
How to find the Katipo spider
Katipo spiders are rarely found more than a few hundred yards form the sea; except for when the sand dunes extend further away from the beach than this (Forester& Forster, 1973). Katipo create their webs and retreats amongst grasses, driftwood and rubbish such as old cans. As the katipo is very small, there are possibly many hours searching the bases of sand dune grasses, driftwood and rubbish.
Abundance and Conservation Status
- New Zealand: endangered
- Canterbury: endangered
There are a few clusters of katipos situated around the coast of New Zealand, but their numbers have declined. The Department of Conservation, Regional and City Councils are obliged by the Resource Management Act 1991 and Angender 21 agreement 1992 to protect the Katipo spider (Griffiths, 2002). The katipo is assessed as a category B threatened species and there are 19 sites that are proposed for conservation (Patrick, 2002) (Table 1).
| DOC Conservancy | Site |
|---|---|
| Bay of Plenty | Papamoa Beach |
| Hawke’s Bay | Ocean Beach |
| Porangahau | |
| Herbertville | |
| Wanganui | Whangaehu River |
| Himatangi Beach | |
| Wellington | Te Humenga Point |
| Flat Point | |
| Uruti Point | |
| Lake Onoke Spit | |
| Nelson | Cape Campbell |
| Maori Pa Beach | |
| Farewell Spit | |
| West Coast | Karamea Beach |
| Canterbury | Kaitorete Spit |
| Orari River mouth | |
| Woodend* | |
| Kairaki* | |
| Otago | Karitane Spit |
Significance for people
Traditional Maori significance and uses
Maori legends recall many deaths (Hornabrook, 1981 cited Patrick, 2002) from the poisonous bite. The Maori awareness of the katipo is summed up by: “the natives generally avoided sleeping on the sea beach, but have no fear of the katipo half a stone throw inland from the beach”( Missionary Revd. Chapman cited Forster& Forster, 1973).
Modern Uses
As yet no modern use has been found for the katipo spider. Through the development of science an antidote to its poisonous bite has been created (Kai, 1984); currently there has been no need for it. The katipo is as historically significant as it is endemic to New Zealand.
Summary
The katipo is an endemic species found nowhere but here in New Zealand. The markings of this spider are unique compared to other species; even to their closest relative the Australian red back. The female is distinct from the male. A red stripe runs down the female’s black abdomen and the male has a predominantly white abdomen. The katipo has been a highly feared spider in the past because of its poisonous bite. Bite incidents are now extremely uncommon; though this could be due to the diminishing population of this species. The results of human activity and interactions with the sand dunes have had a large impact on this small spider. The katipo spider should be looked after as it is a part of ancient New Zealand ecology and should be around to fascinate younger generations.
References
Forster, R. & Forster L. (1999). Spiders of New Zealand and their Worldwide Kin. University of Otago Press, Dunedin.
Forster, R. R. (1967). Spiders of New Zealand part one. Otago Museum Trust Board, Dunedin.
Forester, R. R. & Forester, L. M. (1973). New Zealand Spiders; an Introduction. Collins Bros. & Co Ltd, Auckland.
Green, O. & Lessiter, M. (1992). Fascinating spiders. The Bush Press, Auckland.
Griffiths, J. W. (2002). Web site characteristics, dispersal and species status of New Zealand's katipo spiders, Latrodectus katipo and L. atritus: a thesis submitted in fulfilment of the requirements for the degree of Doctor of Philosophy at Lincoln University, Canterbury, New Zealand.
Johnson, P. (1992). The sand dune and beach vegetation inventory of New Zealand.2, South Island and Stewart Island. Christchurch. DSIR Land resources.
Kai, W. S. (1984). Red-Back Spider, Recognition and Significance risk of establishment. Insect pests in NZ: biology: significance and control of wasps, bees, silverfish, booklice, brown house moth, borers, termites, earwigs, slaters, millipedes, Darwin's ants, Indo-Malaysian cockroach, red back spider, katipo spider, black field cricket: use of controlled-pesticides. Ministry of Agriculture and Fisheries, Wellington.
McLachlan, A. (2001). Spider distribution in agroecosystems in Canterbury, New Zealand: a thesis submitted in partial fulfilment of the requirements for the degree of Doctor of Philosophy at Lincoln University, Canterbury, New Zealand.
Patrick, B. (2002). Conservation status of the New Zealand red katipo spider (Latrodectus katipo Powell, 1871). Science for Conservation 194, Department of Conservation, Wellington.
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