Spiders in New Zealand

What to look out for and keeping yourself safe

New Zealand is home to about 2500 kinds of spiders, most of them harmless to people. Only some spiders are capable of biting humans. There are three species of spiders in New Zealand that should be avoided – the Katipo, the Redback and the White-tailed Spider.

The katipo (Latrodectus katipo) and the redback spider (Latrodectus hasselti) belong to the same genus as the American black widow spider. These two are the only spiders venomous to people in New Zealand. In both species it is the adult females that are capable of biting humans. Bites from both species are extremely rare and there is a safe and effective antivenom for both redback and katipo bites.

What to do if you think you have been bitten by a katipo or redback spider

If you suspect you have been bitten by a katipo or redback spider you need to seek urgent medical attention at your nearest hospital, medical centre or doctor. Even if you do not immediately experience symptoms beyond the ‘pin prick’ of the bite you still need medical advice.

Do

• clean the wound with antiseptic or warm soapy water
• place ice on the bite (not directly onto the skin) prior to travelling.

Do not

• apply pressure to the wound
• consume alcohol after being bitten.

Do not panic as serious reactions are uncommon and unlikely to develop in less than three hours. Hospitals can provide safe and effective treatment. Venom is not always introduced with the bite. If it is, most reactions to the venom are moderate.

What to do if you think you have been bitten by a white-tailed spider

If you suspect you have been bitten by a white-tailed spider only simple first aid is necessary, as with any puncturing of the skin, as these spiders do not cause skin damage or ulcers:

• clean the bite area with antiseptic or warm soapy water
• place ice on the bite (not directly onto the skin) to reduce any pain or swelling.

For any suspected spider bite, see a doctor if the bite area becomes very red or painful, blisters, appears infected, or forms an ulcer. If you are concerned contact the National Poisons Centre (0800 POISON / 0800 764 766) for advice.

Catch the culprit

With all suspected spider bites it is important to know which spider may have been responsible. Try to capture the spider without endangering anybody and take it to the doctor or hospital with you, or describe it carefully for identification. With suspect spiders:

• approach with caution – do not handle
• you may wish to use a fly spray that claims to be effective on spiders to stun the spider before killing it and/or placing it in a sealed jar.

Katipo spiders

Photo: The Otago Museum

What do they look like?

Katipo females (Latrodectus katipo) have black rounded bodies with slender legs and a white-bordered red stripe on their back and a red hourglass mark underneath. Adult males and juveniles are black and white and smaller than the females.

Where are katipo found?

The Katipo (meaning ‘night-stinger’ in Māori), a shy native spider, is on the decline in New Zealand due to changes in its habitat. It makes its webs on warm sandy beaches and sand dunes under:

• beach grasses and other vegetation
• stones and driftwood
• debris such as empty tin cans or bottles.

Katipo are found in coastal areas in both the North and South Islands as far south as Karitane and Greymouth.

Bites

Because of the katipo’s increasing rarity and non-aggressive nature bites are rare. Typical symptoms of katipo bites include pain at the bite site, which may spread to other areas, becoming more intense over the next few hours. People may also experience sweating, difficulty in breathing and abdominal cramps.

How to avoid being bitten

To avoid contact with the katipo wear footwear when walking on the beach and sand dunes where the spiders live. Take care when moving debris and plants on beaches. Avoid draping clothing or towels over driftwood.

Redback spiders

Photo: Dr Julian White

What do they look like?

Female Redback Spiders (Latrodectus hasselti) have black rounded bodies with slender legs and a white-bordered orange to red jagged stripe on their back and a red hourglass mark underneath. Adult males are slender with a cream abdomen with brown stripes and juveniles have additional white markings on the abdomen. Both the males and the juveniles are smaller than the females.

Where are they found?

Redback spiders are originally from Australia. They have been established in limited areas in New Zealand since the early 1980s and continue to arrive in cargo such as motor vehicles, machinery, fruit and containers, usually those imported from Australia. They make their thimble-shaped webs on the undersides of ledges, stone overhangs and vegetation. They are more likely than katipo to make their homes around houses to take advantage of the warm environment. Small redback populations have been reported in Central Otago (around Wanaka) in the South Island.

Bites

Redbacks will only bite when disturbed or trapped in clothing, and bites are rare. The bite feels like a sharp pain similar to a pinprick. The bite may lead to localised redness, pain and sweating. Occasionally the pain and sweating may spread and stomach pain may occur. Aches in muscles and joints, nausea and vomiting, and increased heart rate and blood pressure can result.

How to avoid being bitten

Care needs to be taken when handling imported goods, especially those from Australia. If you do find a redback on recently imported goods, contain it and report it to the Ministry for Primary Industries (MPI) 0800 809 966.

If redbacks have been reported in your area, keep an eye out for them.

• Check clothes and shoes and wear gloves if working in the garden.
• Check behind furniture when cleaning or rearranging inside the house.

Keep areas where children play free of possible spider hiding places. For example:

• fill sandpits to the rim
• trim shrubbery
• keep shrubbery clear of spider webs
• clean swings and other play equipment.

Look-alikes

There is a second native Katipo species, the black Katipo (Latrodectus atricus) which is found mainly in the north of the North Island. It does not have the red stripe of the katipo or redback and is not considered dangerous.

Photo: Museum Victoria

Also very similar to Katipos is the false Katipo, Steatoda capensis, from South Africa, which is now widespread in New Zealand and is found in a range of habitats from houses to beaches. It looks similar to the katipo but its red markings are extremely faint and are limited to the rear most part of the abdomen. The decline in katipo numbers is probably due to Steatoda capensis, as they reproduce more readily than the katipo and are better at taking over newly vacant sites.

Photo: Dr Julian White

White-tail spiders

Photo: Dr Julian White

What do they look like?

White-tailed spiders (Lampona murina and Lampona cylindrata) are quite distinct with dark bodies and a white patch at the end of their cylindrical/cigar-shaped abdomen. The juveniles and males have patches on their abdomen as well as white ‘tails’.

Where are they found?

White-tailed spiders are from Australia. Lampona murina has been in the North Island for over 100 years and Lampona cylindrata has become widespread in the South Island since about 1980. Both species of white-tailed spider live almost entirely on other spiders. They can be found in vegetation in gardens and bush, and around houses, which they like for the warmth. White-tailed spiders do not build webs.

Bites

The usual white-tailed spider bite can be painful but the initial burning feeling, swelling, redness and itchiness at the bite site usually goes and there are no long-lasting effects. White-tailed spider bites are not considered poisonous to humans. An Australian study has shown no evidence linking necrotic ulcers (destroyed skin) to white-tailed spider bites.

How to avoid being bitten

White-tailed spiders around the house can be controlled by killing any that you see and by regularly clearing away the webs of the house spiders that they feed on. Avoid putting your hands behind furniture or into places where spiders may be hiding.

Contact

For further information about spider bites and venom contact:

• National Poisons Centre 0800 POISON [0800 764 766]
• Local DHB public health unit
• Ministry of Health www.moh.govt.nz
• Healthline 0800 611 116

For reporting spiders associated with recently imported goods, contact MPI 0800 809 966

With thanks to Dr Phil Sirvid, Te Papa and Dr John Fountain, National Poisons Centre.