White-tailed Spider

Introduction

White-tailed Spider bites have been controversially implicated in causing severe skin ulceration in humans.

Identification

White-tailed Spiders have a dark reddish to grey, cigar-shaped body and dark orange-brown banded legs. The grey dorsal abdomen bears two pairs of faint white spots (less distinct in adults) with a white spot at the tip; the male has a hard, narrow plate or scute on the front of the abdomen. The two common species in southern Australia, Lampona cylindrata and L. murina, are similar in appearance and have overlapping distributions in the south-east. Their bites have been controversially implicated in causing severe skin ulceration in humans.

Habitat

White-tailed Spiders are vagrant hunters that live beneath bark and rocks, in leaf litter, logs and detritus in bush, gardens and houses.

Distribution

Lampona cylindrata is found across southern Australia (south east Queensland, New South Wales, Victoria, South Australia, Tasmania, Western Australia). Lampona murinais present in eastern Australia from north-east Queensland to Victoria (Queensland, New South Wales, Victoria,).

Feeding and diet

They are most active at night when they wander about hunting for other spiders, their preferred food. They have been recorded eating curtain-web spiders (Dipluridae), daddy-long-legs spiders (Pholcidae), Redback Spiders (Theridiidae) and black house spiders (Desidae) During summer and autumn White-tailed Spiders are often seen in and around houses where they find both sheltered nooks and crannies and plenty of their favoured black house spider prey.

Life history cycle

Tufts of specialised scopulate hairs on the ends of their legs allow them to walk easily on smooth or sloping surfaces. They make temporary silk retreats and spin disc-shaped egg sacs, each containing up to 90 eggs.

Management

White-tailed Spiders around your house can be controlled by catching and removing any that you see and by clearing away the webs of the house spiders upon which they feed.

Danger to humans

White-tailed Spider bites can cause initial burning pain followed by swelling and itchiness at the bitten area. Occasionally, there are unconfirmed reports of weals, blistering or local ulceration - conditions known medically as necrotising arachnidism.

A debate continues about the involvement of White-tailed Spider bite in cases of severe ulcerative skin lesions seen in patients diagnosed as probable spider bite victims. Typically, in such cases no direct evidence of spider bite is available. Sensational media reporting of supposed cases of severe "necrotising arachnidism" has given the White-tailed Spider a bad reputation. However, a recent study has monitored the medical outcomes of over 100 verified White-tailed Spider bites and found not a single case of ulceration (confirming the results of an earlier study). The available evidence suggests that skin ulceration is not a common outcome of White-tailed Spider bite.

References

• Isbister, G.K. & Gray, M.R. 2003. White-tail Spider bite: a prospective study of 130 definite bites by Lampona species. Medical Journal of Australia 179: 199-202.
• Isbister, G. & Gray, M. 2000. Acute and recurrent skin ulceration after spider bite Medical Journal of Australia 172: 303-304
• Platnick, N.I. (2000). A relimitation and revision of the Australasian ground spider family Lamponidae (Araneae: Gnaphosoidea). Bulletin of the American Museum of Natural History 245: 330 pp.
• Sutherland, S. & Sutherland, J. 1999. Venomous Creatures of Australia. Oxford University Press, South Melbourne Vic.
• White, J. 1998. Response to Chan, S.W. 1998. Recurrent necrotising arachnidism. Medical Journal of Australia 169: 642-643