White-tailed spiders are vagrant hunters who seek out prey rather than spinning a web to capture it. Their preferred prey is other spiders and they are equipped with venom for hunting.
They are known to bite humans and effects may include local pain, a red mark, local swelling and itchiness; rarely nausea, vomiting, malaise or headache may occur. Ulcers and necrosis have been attributed to the bites, but a scientific study by Isbister and Gray (2003) showed these were probably caused by something else, as the study of 130 white-tailed spider bites found no necrotic ulcers or confirmed infections.
Ludwig Carl Christian Koch described Lampona cylindrata in 1866 and Lampona murina in 1873. The genus name comes from the Latin lampo which means shine. The species name cylindrata refers to the cylindric body shape, while murinus means "mouse-gray" in Latin.
DescriptionEditThe two common species of white-tailed spiders are Lampona cylindrata and Lampona murina. They are similar in appearance; L. cylindrata is slightly larger with females being up to 18 mm long while males are up to 12 mm in body length. The legs span approximately 28 mm in diameter. The two species are not easily distinguished from one another without microscopic examination. They are slender spiders having dark reddish to grey, cigar-shaped body and dark orange-brown banded legs. The grey abdomen has two pairs of faint white spots and a distinct white spot at the tip just above the spinnerets.
The similarities have led people to think there is only one species of white-tailed spider. It is possible that not all white-tailed species have been identified. The descriptor, white tail, is applied to a variety of species of spiders for which a distal white mark on their abdomen is a distinctive feature; other markings disappear with moultings but the white tail remains to adulthood.
L. cylindrata lay pinkish eggs which are enclosed in a flattened silk capsule and are guarded by the female until they hatch.
DistributionEditBoth species are native to Australia. Lampona cylindrata is present across south-east Queensland, New South Wales, Victoria, South Australia, Tasmania and Western Australia while Lampona murina is found in eastern Australia from north-east Queensland to Victoria. The spiders have been introduced in New Zealand with Lampona murina residing in the North Island for over a hundred years while Lampona cylindrata has become widespread throughout the South Island since 1980.
Habitat and behaviourEdit
They live in gardens and inside houses, beneath bark and rocks, in leaf litter and are often found in the folds of clothes, towels and shoes. They do not build webs. Most active at night, they hunt for other spiders. Their favoured prey is the black house spider.
Bites to humansEdit
White-tailed spiders wander about human dwellings and may be encountered unexpectedly, unlike the black house spider and the redback which are more often seen in a web. They may be responsible for a disproportionately high number of spider bites compared with other Australian spiders, because of their wandering habits. Of the 130 cases studied by Isbister and Gray, more than 60% of the victims had been bitten by spiders that had got into clothing, towels or beds.
The bite of white-tailed spiders has been wrongly implicated in cases of arachnogenic necrosis. The misassociation stems from a paper presented at the International Society on Toxinology World Congress held in Brisbane in 1982. Both white-tailed and the wolf spider were considered as candidates for possibly causing suspected spider bite necrosis, though it later turned that the recluse spider was the culprit in the reported cases from Brazil.
Following this initial report, numerous other cases implicated white-tailed spiders in causing necrotic ulcers. All of these cases lacked a positively identified spider—or even a spider bite in some cases. Additionally there had not been a case of arachnogenic necrosis reported in the two hundred years of European colonisation before these cases. Clinical toxicologist Geoffrey Isbister studied 130 cases of arachnologist-identified white-tailed spider bites, and found no necrosis or confirmed infections, concluding that such outcomes are very unlikely for a white-tailed spider bite. The major effects from a bite were local pain, a red mark, local swelling and itchiness; rarely systemic effects of nausea, vomiting, malaise or headache occurred. All these symptoms are generally mild and resolve over time.