White-tail spider bites: what the research actually says

White-tail spider bites hurt, but the evidence says they don’t cause the “flesh-eating” ulcers they’re famous for. A study of 130 confirmed white-tail bites, published in the Medical Journal of Australia, found no necrotic ulcers and no confirmed infections. Expect burning pain, a red mark and some swelling, and see a doctor if it’s severe or doesn’t settle.

White-tails are a common sight in Barossa and Adelaide homes in the warmer months, and they cause a lot of worry. Here’s what the research actually found, how to recognise one, and why they come inside.

What a white-tail spider looks like

According to the Australian Museum, white-tails have a dark reddish to grey, cigar-shaped body, orange-brown banded legs and a white spot at the tip of the abdomen. Females grow to about 18 mm and males to about 12 mm. The two common species in southern Australia are Lampona cylindrata, which is found in South Australia, and Lampona murina in the east.

What the research found

In 2003, Geoffrey Isbister and Michael Gray published a study in the Medical Journal of Australia that followed 130 bites where the spider was caught and identified by an expert. The results:

• Pain in every case, and severe pain in 27%.
• A red mark in 83% of cases.
• No necrotic ulcers at all, and no confirmed infections.
• 95% of bites happened indoors, mostly in the warmer months from September to April.
• Three quarters happened between 4 pm and 8 am, often when the spider was caught in bedclothes, towels or clothing.

The authors concluded that white-tail bites are very unlikely to cause necrotic ulcers and that other diagnoses should be looked for. Current advice from healthdirect matches: white-tails aren’t considered dangerous to humans, a bite can cause burning pain, swelling and blisters, and current evidence suggests the bites do not cause skin ulcers.

So if you have a sore that won’t heal, don’t assume it’s a spider bite. See a doctor so they can find the real cause.

Why white-tails come inside

White-tails don’t catch food in a web. They wander at night hunting other spiders, and black house spiders (the ones with the lacy webs in your window frames) are a favourite. The Australian Museum notes that in summer and autumn they are often seen in and around houses, where they find both shelter and plenty of prey.

That’s the useful part: if there are fewer webbing spiders on and around the house, there’s less for white-tails to hunt. A proper spider treatment deals with the webbing spiders they feed on, not just the one you saw on the wall.

Simple ways to avoid a bite

• Don't leave towels and clothes on the floor overnight, and give them a shake before you use them.
• Shake out bedding that's been folded away or left on a spare bed for a while.
• Check shoes before putting them on, especially ones left by the door.
• Brush down the lacy black house spider webs around window frames and eaves.
• Fit door seals and keep flyscreens in good repair.

Getting them under control

Seeing the odd white-tail isn’t a crisis. Seeing them regularly usually means there are plenty of webbing spiders around the house for them to feed on. Our spider control treats eaves, window and door frames, garages and sheds, plus the inside corners spiders favour, so the whole population thins out. Many customers book it as part of an annual general pest treatment.

For a free quote, call Garry on 0403 018 325. We cover the Barossa Valley, Gawler, Salisbury & Elizabeth and the wider Adelaide area.