L. Koch, 1866
L. Koch, 1873
White-tailed spiders are medium-sized spiders native to southern and eastern Australia, and so named because of the whitish tips at the end of their abdomens. Common species are Lampona cylindrata and Lampona murina. Both these species have been introduced to New Zealand.
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.
The 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—usally but not always—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.
Both 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 behaviour
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. According to the Queensland Museum they cannot climb glass. Most active at night, they hunt for other spiders. Their favoured prey is either the black house spider or the closely related brown house spider (Badumna longinquus), both of which are, like the whitetail, native to Australia but have been inadvertently introduced to New Zealand.
Bites to humans
The effect of white tailed spider bites remains controversial. Formal studies are few, the most recent studies finding no evidence for associations of long term skin infections or necrosis from white tail spider bites. The community and anecdotal view remains that white tail spider bites can be associated with long term skin infections, and in rarer cases progression to necrosis.
Suspected white tail spider bites on humans is more difficult to determine for this spider than spider bites from many other spider species. Most house resident spiders remain mostly in webs. In this regard human interaction more often involves a hand or body part or whole body entering a web, with prospect of being bitten immediately apparent. A cobweb associated with the spider often visible aiding identification. In these circumstances the spider is visible on an external visible part of the body or on external surface of clothing. When bitten, the pain of bite is immediate and the source of the bite, the spider, often looked for immediately and found. In contrast, white tailed spiders are generally not found in webs, instead wondering freely about domestic environments. Wolf spiders are another species that similarly wonder in Australian homes where white tailed spiders are found. White tail spiders seek dim light locations and their body shape enables migration through fabrics, clothing, bedding in out of sight movements. Unlike many other spider bites, the bite may not be felt at the time. It is hours later that itching and a spider bite is suspected. It is not uncommon for a white tail spider to be found in bedding slept in, or in worn or removed clothing, with a bite site appearing some hours later. It is the consistent association of white tails spiders present in bedding or worn clothing with apparent bite sites being identified in hours following, with no other identifiable sources for the bite, that lead to community and anecdotal views of an association. Of the 130 cases of white tail spider bites studied by Isbister and Gray, more than 60% of the victims had been bitten by spiders that had got into clothing, towels or beds.
Anecdotal reported responses to white tail spider bites varies considerably.
At the rarer and more intense end of the spectrum of suspected white tailed spider bites, the response is quite strong and immediate. No initial bite may have been felt. Typically a skin rash quickly spreads over several to tens of centimeters in a matter of an hour or two, with feelings of nausea, headache, pain. Symptoms are sufficiently intense that medical attention is often sought.
At the other end of the spectrum, and more commonly, the response is much milder and gradual. Again the bitten person will often report feeling no bite. The bite appears similar and is often initially mistaken for a normal mosquito bite. Bites during sleep in bedding are often on extremities, with elbows, back of hands, feet, ankles, and knees common sites. The differentiation from a mosquito bite becomes apparent in two ways over the following days. First the itchy bite does not fade and resolve as would be expected with a mosquito bite, with instead the itchy and reddened area expanding. Secondly and most distinctively, one or more small blisters appear within the bite area after one to seven days. At this stage application of methylated spirits on the itchy bite area over a few days has been anecdotally reported to dry out the skin around the bite site and stop progression. Untreated, sometimes the bite resolves itself, other times the bite site continues to grow over weeks becoming a source of increasing concern and complication eventually requiring medical attention. In the second case, more blisters form and the itchy area continues to expand slowly, with increased deterioration of the skin in the centre of the affected area, and over several weeks to a larger area of several centimeters, progressive deterioration, cellular breakdown, and infection of the area. This is a trend towards necrosis. Treatment with antibiotics is the typical response at this stage.
The issue of necrosis in some bite cases in published studies begins with 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 in the Australian context. In Brazil the recluse spider was identified as linked to necrosis.
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 in this study 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.
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