True or false, did the false widow spider bite?

A man has ended up in hospital after being bitten by what was thought to be a false widow spider.

Jason Fricker, 34, was working on his market stall in Salisbury, UK, when he felt a sharp pain in his chest. After checking under his shirt he saw a spider run away. Over the next few days Jason's condition deteriorated and he had to have emergency treatment in hospital.

Was it a false widow?

The Natural History Museum's Insect identification Service identifies specimens brought in by the public. In this case, the spider ran off and couldn't be captured, so it wasn't formally identified. 

The culprit spider was described as looking very much like one of the false widow spiders, Steatoda nobilis , but there are a number of similar looking species such as the black widow .

The incident happened in a market, so it is possible that the culprit may have been an exotic spider accidentally shipped over in a fruit container from overseas. Non-native species that can be accidentally imported are the black widow (from Southern USA and Mexico), the huntsman (a familar spider in SE Asia and the Caribbean) and another species of false widow spider called Steatoda paykulliana (found in Southern Europe, North Africa and Western Asia).

'It's quite possible it was an exotic spider,' says Stuart Hine, invertebrate specialist at the Natural History Museum. However, he went on to say that 'if indeed these severe symptoms were wholly attributed to the spider then I would say they are a bit extreme for the bite of S. nobilis in a healthy adult.'

Living in the south

Originally from Southern Europe, the false widow spider is now established in the south and east of England but as global warming continues, areas further north are becoming more favourable for the spiders.

Steatoda nobilis is one of six species of the genus, or group, Steatoda , found in the UK. They are commonly called false widow spiders as they are often mistaken for black widow spiders, but their bites and venom are much less harmful to humans.

Spiders and their bites

There are about 35,000 species worldwide. In general all spiders are venomous, as this is the method by which they stun and kill their prey, but the venom of most has little or no effect on humans.

Out of 640 species of spiders in the UK, only twelve have been reported as being able to penetrate human skin with their bite, and these tend to be our larger species.

Symptoms from the bites of most of these are fairly generic, such as local pain and swelling, and symptoms are certainly no worse than those from a bee or wasp sting.

Other spiders, notably Steatoda nobilis and Nuctenea umbratica have been reported as causing more severe symptoms including flu-like episodes, palpitations and hot/cold sweats.

'To my knowledge there has not been a recorded death from spider bite in the UK,' concludes Stuart. 'If bitten by a spider in the UK, and symptoms are greater than slight to medium local pain and swelling, I would recommend that medical advice be sought.'