Dorothy Russell, of Kurow, asks :-

I have two whitetail spiders in my house. Can you enlighten me about them please?

Cor Vink, an entomologist with the Biosecurity Group at AgResearch and the Adjunct Curator of Spiders at the Entomology Research Museum at Lincoln University, responded.

The whitetail spider that you found in your house would have just been passing through on its search for spider prey.

There are two species of whitetail spiders found in New Zealand; Lampona cylindrata are found in the South Island and Lampona murina are found in the North Island. Both species were accidentally introduced from Australia during colonial times.

Their natural habitat in Australia is under tree bark or in dry leaf litter; in New Zealand they are usually found in and around buildings where they feed on the grey house spider (Badumna longinqua) and the black house spider (Badumna insignis), which are also both from Australia. Whitetail spiders don’t build their own web but wander in search of other spiders’ webs. They are usually encountered by people at night as whitetail spiders are nocturnal. When a whitetail spider finds a spider web, they pluck it and its owner rushes out assuming there is a trapped insect. The whitetail spider then attacks the spider, biting it at the base of one of its legs. Whitetail spider venom is extremely effective against other spiders, killing them in about ten seconds. A whitetail spider doesn’t need to feed very often; one spider every month or so is adequate.

Whitetail spider bites pose little threat to humans other than causing immediate pain, much like a wasp sting. There is absolutely no scientific evidence that their bites cause necrotising wounds. In some cases a persistently painful lesion can last for up to three days. If a whitetail spider does bite, the wound should be cleaned to avoid the possibility of a secondary infection. Ice, anti-inflammatories and/or anti-histamines can provide relief from the pain.