Overview
Scientific names: Lampona cylindrata and L. murina
What do they look like?
Slender looking spiders, typically greyish in colour with banded legs and usually with a distinct cream-white marking on the tip of the tail. Males and juveniles may have additional white markings on the abdomen. The leg span of a fully grown specimen is a little over 3cm.
The two species present in New Zealand cannot easily be distinguished from one another without examination under a microscope.
Where are they found?
Both species originate from Australia. Lampona murina has been known in the North Island for well over a hundred years and has also been introduced into the Kermadec Islands.
Previously known from only a handful of records from Nelson, a second species of white-tailed spider, Lampona cylindrata, has become widespread throughout the South Island since about 1980.
The New Zealand distribution of white-tailed spiders mirrors their respective ranges in Australia, where L. cylindrata is found in the south of Australia and L. murina has a more northerly distribution. In New Zealand these spiders are strongly associated with urban habitats.
What are their habits?
These spiders do not build a web to catch their prey as they are active hunters. They are rather unusual in that they specialize in catching other spiders, particularly the common and well established Australian species the grey house spider (Badumna longinqua).
The white-tailed spider will cautiously enter the web of its intended victim and mimic the struggles of a trapped insect by plucking at the web. This may trick the resident spider into investigating the disturbance and so instead of gaining a meal, it becomes one when the white-tail strikes.
What is their bite like?
There are numerous newspaper accounts of particularly nasty bites that are allegedly caused by these spiders. However, the evidence that white-tailed spiders are responsible is rather weak.
Bites are often attributed to these spiders, even when the creature that inflicted the bite was never sighted. Infection of the bite area seems to be a far more likely cause of medical problems than the spider's venom.
Where these spiders are positively identified as causing a bite, typical symptoms include pain and swelling at the bite site. The bite can develop into a small ulcerous wound that heals inside a week. In some instances, victims report flu-like symptoms.
In any case, spider bites should always be cleaned and watched for signs of infection. Should any adverse symptoms occur, seek medical advice.