The UK’s most poisonous spiders

Just 1,000th of a raindrop’s worth of venom from a noble false widow spider can be harmful

False widow spider
The false widow is one of around 650 species of spider found in the UK
(Image credit: ePhotocorp/Getty Images)

A mother whose baby was bitten by a noble false widow spider is trying to raise public awareness of the dangers posed by the invasive species.

Sarah Jane Dennehy, from County Cork in Ireland, told the BBC that her 15-week-old son, Charlie, was “lying on his mat and all of a sudden he went apocalyptic – he had a real bout of purple screaming”.

Charlie was treated at the accident and emergency department of his local hospital, but the effects of the venom took 11 hours to wear off. “I want people to be aware that there are venomous spiders in Ireland and the UK,” she told the BBC. “These false widow spiders are decimating the native spider population.”

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Warning of the dangers of false widow spiders, Dr John Dunbar, from the National University of Ireland, Galway (NUIG), told Sky News: “The tiniest amounts of venom – about 1,000th of a raindrop – can cause medically significant symptoms in humans that are about 250,000 times larger than them.”

That said, it is fairly rare to come across a biting spider in the UK. While around 650 species of spider are found in Britain, only 12 of them have reportedly bitten humans. Of these, just “two or three have been known to give a significant or unpleasant bite”, said the National History Museum.

Although the risk of obtaining a dangerous spider bite remains low in the UK, the noble false widow spider is reported to have been breeding “in high numbers across Britain” this summer thanks to “scorching” temperatures, said The Mirror.

Here’s what you need to know about these venomous creatures – and Britain’s other most poisonous spiders.

False widow spiders

The three most common types of false widow spiders are the rabbit hutch spider, the cupboard spider – named after its preferred habitat – and the noble false widow.

The largest and most commonly reported is the noble false widow, said the Natural History Museum, and it was first recorded in the UK in the 1870s. “It is only since the 1980s that the species has gained a strong foothold,” added the museum, “forming established populations in the majority of the southern counties – although it has now spread northwards”.

A recent study by a team of researchers at NUIG concluded that the bite of a noble false widow spider is “up to 230 times more venomous than native Irish spiders” – and the creatures are thought to be the most venomous type of spider in the UK.

A bite from a false widow can cause pain, swelling, numbness, discomfort, burning, chest pain and nausea. However, said The Mirror, although they have a venomous bite, the poison isn’t particularly potent as “the symptoms should only last between one and 12 hours, and rarely for more than 24 hours”.

Walnut orb-weaver spiders

Walnut orb-weaver spiders are the second most venomous of their species in the UK. These creatures hide away during the day in nooks and crannies or under bark, said the Nature Spot website.

The pain from their bites has been described as feeling “like an electric shock” and can cause burning, swelling and numbness.

Wasp spiders

The venom from the unsettlingly named wasp spider often moves to the victim’s groin. It’s lucky, therefore, that this type of spider is relatively rare in the UK.

The female wasp spider has “yellow, black and white stripes, just like a common wasp”, said The Wildlife Trusts. The male is smaller and pale brown.

Black lace-weaver spiders

Unless three days of swelling and nausea is your thing, then it’s best to avoid being bitten by a black lace-weaver. Mostly found under stones and logs in gardens, these creatures can reach up to 15mm in length, said the UK Safari website.

They are “known to bite people in surprise attacks, with their venom causing a dull pain which lasts for around 12 hours”, added The Sun. “It will also cause swelling and redness, eventually giving way to blisters.”

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