White-tailed (Lampona cylindrata & Lampona murina)

Physical description and identification

Two species carry the name white-tailed spider: Lampona cylindrata and Lampona murina. They look almost identical in the hand and cannot be separated without a microscope and an adult specimen, because the difference is in the genitalia rather than the markings. Geography splits them: L. cylindrata is the larger, southern species, L. murina the eastern one. Everything below applies to both.

Adults

• Size: females of L. cylindrata reach about 18 mm in body length and males about 12 mm, with L. murina slightly smaller. Leg span is around 28 mm.
• Shape: the most useful field character. The abdomen is narrow, elongated and cylindrical, and the carapace low and flattened — nothing else in an Australian house has this silhouette.
• Colour: dark grey to greyish brown, sometimes with a purplish cast, and legs banded in deep orange-brown. The grey abdomen carries one distinct white spot just in front of the spinnerets. Juveniles also show two faint pairs of pale patches further forward, which fade in adults — so descriptions of "four white spots" describe young spiders, not mature ones.
• Eyes: eight small, similar-sized eyes in two short rows on a low face, none enlarged — very different from the big-eyed wolf spiders and jumping spiders. See our guide to spider eyes.

Eggs and egg sacs

A mature female lays roughly 80 to 100 pinkish eggs in a single flattened, disc-shaped white silk sac built inside a crevice — under bark, beneath a rock or in a roof cavity. She stays with the sac until the spiderlings emerge, and may produce more than one in a season.

Spiderlings

Hatchlings are pale with dark markings and disperse on foot. Ballooning has not been demonstrated for Lampona, and the claim that the young are carried away on the air is unsupported — these are heavy-bodied bark dwellers that walk. Juveniles hunt smaller spiders from the start and take a year or more to mature, growing by moulting.

The hunt, not the web

White-tailed spiders build no capture web. Silk is used for the egg sac, draglines and a flimsy temporary retreat in which the spider rests by day. They are nomadic nocturnal hunters and — unusually — spider specialists. At night a Lampona walks the walls, fences and bark of its territory, finds another spider's web and invades it, moving in slowly before biting the resident. The staple prey is the black house spider, with the grey house spider, daddy-long-legs and juvenile redbacks.

Where white-tailed spiders live

Both species are native to Australia. Lampona cylindrata occupies the southern half of the continent — South Australia, Victoria, Tasmania, southern New South Wales and south-west Western Australia — and is the species usually found in Melbourne and Adelaide homes. Lampona murina runs from Queensland into Victoria and is the one met around Sydney. Both are established in New Zealand, almost certainly arriving as stowaways in freight.

The habitat is bark, litter and crevices — any gap a flat-bodied spider can slide into by day. In bushland that means loose bark, logs, rocks and leaf litter; around houses, mulch, woodpiles, wall cavities, roof spaces and clothing left on the floor. Populations follow their prey: a house with black house spider webs on the eaves will have white-tails hunting them. The old claim that these are grassland spiders is wrong.

Are white-tailed spiders venomous?

Yes, they are venomous, and no, the venom is not dangerous to people. That is the single most important thing to know about the species, because the opposite has been repeated for forty years.

The necrosis story began in the 1980s, when a handful of Australian case reports linked severe ulcerating skin lesions to suspected white-tailed spider bites — almost always without the spider being caught or identified. "White-tail bite" became the default explanation for any unexplained ulcer.

It was tested properly by Geoffrey Isbister and Michael Gray in a prospective study published in 2003, following 130 definite Lampona bites, every one with the spider collected and identified by an arachnologist. Not a single case produced necrosis or an ulcer. The typical outcome was pain, a red mark and itching, with a minority reporting nausea, headache or malaise. Later reviews reached the same conclusion, and the original ulcers are now attributed to other causes — bacterial infection, vascular and diabetic ulcers, pyoderma gangrenosum and misidentified skin cancers.

No antivenom exists for Lampona and none is needed. Australia's dangerous spiders are the funnel-webs and the redback, and neither resembles a white-tailed spider.

Can white-tailed spiders bite?

They can and they do. These spiders wander at night and end up in clothing, shoes and bedding, and one pressed against skin will bite — which is why it is among the more commonly recorded spider bites in southern Australia.

What a bite does. Most people feel immediate sharp or burning pain, then a red mark or small weal, local swelling and persistent itching. In the Isbister and Gray series the pain lasted minutes to a few hours and the mark faded over days. About one bite in four brought a mild systemic complaint — headache, nausea or malaise. Confirmed tissue death was not seen.

What to do. Wash the site with soap and water, apply a cold pack and take a simple painkiller if needed. Keep it clean and resist scratching: secondary bacterial infection, not venom, is the realistic risk. Seek medical care if pain is severe or spreading, if the area becomes hot and increasingly swollen after a day or two, if you develop a fever, or if there is breathing difficulty or a widespread rash. Do not use a pressure-immobilisation bandage (that is for funnel-web and snake bites), and do not cut, suck or heat the wound.

Ecological importance and behaviour of the white-tailed spider

The white-tailed spider is an araneophage — a spider that eats spiders. It hunts alone at night without a web, invading the webs of web-builders and killing the occupant on its own ground — dangerous work, managed by approaching slowly, feeling the silk and striking first. Known victims include the black house spider, the grey house spider, cellar spiders such as the long-bodied cellar spider, curtain-web spiders and juvenile redbacks.

Why that matters: a resident population suppresses the webs on your eaves, so removing them increases house spider webs rather than reducing them.

Natural predators: birds, geckos and skinks, centipedes, spider-hunting wasps and larger spiders including huntsmen — see what eats spiders.

Season and lifespan: adults occur year-round in mild areas but peak in summer and early autumn, when wandering males and indoor sightings both spike. Lifespan is roughly one to two years; the figure of up to twenty years circulating online is wrong, and appears to be a confusion with tarantulas.

Living alongside them: shake out clothing and shoes left on the floor, keep bedding off the ground, move woodpiles away from walls, and brush down the house-spider webs the Lampona are coming for. Sprays are useless against a nomad that never sits in a treated web.

Similar spiders and how to tell them apart

Quick facts

Did you know?

• The genus name Lampona comes from the Greek root meaning "to shine", for the bright spot at the abdomen tip. The species names are descriptive too: cylindrata for the cylindrical body, murina for its mouse-grey colour.
• The definitive bite study collected 130 cases in which the spider itself was caught and identified by an expert. Zero developed a necrotic ulcer.
• They will enter a redback's web to take a juvenile — a genuinely dangerous way to earn a meal.
• The term "white-tailed spider" is loose: several unrelated Australian spiders have pale abdominal tips, so the spot alone does not identify a Lampona. The cigar-shaped body and banded legs do.
• Both species crossed the Tasman as accidental cargo, and the same necrosis myth followed them to New Zealand.

In summary, the white-tailed spider is a nocturnal, web-free hunter of other spiders, native to southern and eastern Australia and naturalised in New Zealand. Its bite hurts and itches and then goes away. It does not cause flesh-eating ulcers, and treating an unexplained ulcer as a spider bite delays the diagnosis that matters.