Health & Safety

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False Black Widow Spider

12 October 2011

Experts have concluded that the milder winters and record breaking hot summers in the UK are keeping alive more of the UK's most dangerous spider the "False Black Widow Spider".

False Black Widow Spider

It used to be only a handful of spiders that would survive the cold weather so the numbers were always kept down. But now they are all surviving the winter and are crawling out of hibernation earlier to mate. The result has been numbers have just rocketed into the hundreds of thousands. The species - only the female of which bites - had been considered native to Devon and Dorset but has spread as far as East Anglia. Recent reports of bites by BT members are in Canvey Island Essex.

The spider has a black/brown bulbous abdomen with pale markings and the females grow to 15mm. They live in walls, fences and the barks of trees and eat insects, other invertebrates and even other spiders. It is closely related to the black widow spider whose poison can be fatal to humans. It poses a threat to gardeners and anyone else working or spending leisure time outdoors. Their nest is small, round, white and is about the same size as a table-tennis ball. They can also be found inside houses.

Gardeners and Outdoor workers have been warned to be on their guard in the future. A bite from the False Black Widow Spider delivers enough poison to cause severe pain and inflammation. The severity of symptoms from any spider bite depends on the amount of venom that is injected. Also flu-like symptoms, aches, sweats, fatigue, perspiring, cold and shaky, chest pains, swelling and tingling of fingers are some of the symptoms which can be experienced. One study found that the pain was far more severe than that from a wasp or bee sting. Normally an antihistamine tablets and cream will take the pain away but, depending on the amount of venom injected, a doctor may need to be seen.

There's no need to panic however, just be aware. Despite increased numbers and range the likelihood of being bitten by a False Black Widow Spider remains very low. No one has ever died of a spider bite in the UK and the number of reported bites from spiders in general is minimal. The Natural History Museum's Insect Information Service hears of about 10 cases of spider bites each year in the UK.