False Widow Spiders
The term "false widow spider" is used to describe a group of species of spider found in the UK. Each of these spiders bares a visual resemblance to the notorious Black Widow Spider to varying degrees. There are six species of false widow spiders that live in the UK (Steatoda nobilis, Steatoda grossa, Steatoda bipunctata, Steatoda albomaculata, Steatoda triangulosa and Steatoda / Asagena phalerata) and one species (Steatoda paykulliana) that turns up as an accidental import, usually on fruit, fairly regularly. The most venomous species in the UK and usually the one referred to as the False Widow Spider by the media is the Noble False Widow Spider (Steatoda nobilis). 

Noble False Widow Spider   (Steatoda nobilis)

The Noble False Widow Spiders were first recorded in the UK over 100 years ago in Dorset and are believed to have been accidentally imported into the UK from the Canary and Medeira Islands amidst crates of fruit. In the last 25 years they have spread further up the country and they are now regularly seen in houses and gardens across England. Nobel False Widow Spiders are the largest of the false widow species in the UK but are still a fairly small spider with females usually growing to a maximum body size of 15mm and a leg-span of 30-35mm. They have recently received great interest from the British press and are often reported as being aggressive, dangerous, highly venomous and deadly. Although capable of delivering a moderately painful bite they are in fact a very docile and slow moving species and have never shown any aggression when I've photographed them.      British Arachnological Society Factsheet

Despite being in the UK for over 100 years the Noble False Widow Spider has recently gained an undeserved reputation which has been generated by sensationalized stories in the media such as these during 2014. These stories are usually completely exaggerated and based on little fact. Rarely has the accused spider been caught for a positive identification and severe reactions from bites are nearly always caused by infection (usually introduced by scratching the bite with dirty hands) and not from the spider itself.

"False Widow Spider ate my leg!"    "False Widow Spider bites teen in cinema"    "Flesh-eating monsters are still here"    "False Widow Spider ate my foot"   

 "False Widow Spiders are eating Dad alive"    "False Widow Spider bite could kill"    "Killer spiders ate my leg"    "False Widow Spider made my leg explode"

"False Widow Spiders attacked my little girl"    "50 False Widow Spiders invade home"    "Killer Spiders invade Britain"    "False Widow Spiders close school"

Sub-adult male Noble False Widow Spider

Sub-adult male Noble False Widow Spider that still has its striped legs and doesn't yet have the black cephalothorax (upper body / head).

Female Noble False Widow Spider

Female Noble False Widow Spider

False widow webs are a messy tangled scaffold of silky threads. The Noble False Widow Spider is primarily a nocturnal species and at night can often be spotted hanging upside down in its messy hammock style web. During the day the spider usually hides away in a crack or crevice in the adjoining wall. False widow spider bites are rare. In most cases a bite is often considered to be no more painful than a bee or wasp sting. Symptoms can include pain, swelling and reddening surrounding the bite area. Sometimes this can be accompanied by nausea and breathing issues depending on the victim's sensitivity to the venom. Most severe cases that include severe swelling and ulceration are caused by infection to the wound. Usually symptoms disappear within 3 days. If symptoms are severe then you should seek medical assistance. In all cases wounds should be cleaned and a disinfectant applied to reduce the risk of infection. Antibiotics should only be taken in the case of infection otherwise they are not needed. An ice pack may be applied to reduce swelling and pain. Avoid scratching or rubbing the bite area as again this could increase the risk of infection.

8mm female Cupboard Spider / False Widow Spider (Steatoda grossa)

False Widow Spider  /  Cupboard Spider  (Steatoda grossa)

Steatoda grossa is another of the UK's False Widow Spiders. A fairly common species which usually has a different habitat to the Noble False Widow Spider, prefering to reside in dark places such as sheds and outhouses, as well in in cupboards in houses. The specimen above was found under a manhole cover above a sewage outlet in my garden in SE London / North Kent. Females have a maximum body-length of around 6.5 - 10mm but the males tend to be slightly smaller and slimmer at around 4 - 7mm. Females can live for around six years in captivity but often only live to around 18 months in the wild. Males usually die after mating. The most distinguishing feature of Steatoda grossa are the two or three triangular or chevron markings on the top of the abdomen, which are not always present on larger female specimens.

8mm female Cupboard Spider / False Widow Spider (Steatoda grossa)

Although not dangerous, the bite of the Cupboard Spider is known to be quite painful to humans but does not cause long term issues. On rare occasion the site of the bite can blister and the victim could suffer muscle spasms, pain, fever and sweating. The antivenin for Latrodectus sp. (Black Widow Spider) is known to be effective in treating serious bites from Steatoda grossa.

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2mm Cupboard Spiderling / False Widow Spiderling (Steatoda grossa), found in my understairs cupboard, 19th June 2019. 

3mm Cupboard Spiderling / False Widow Spiderling (Steatoda grossa), found wandering on my bed, 11th June 2020. 

10mm female Cupboard Spider / False Widow Spider (Steatoda grossa), found under a manhole cover in my garden in SE London, 3rd May 2020.
Some adult female Steatoda grossa have no markings on their abdomen at all, such as the specimen above.

10mm female Cupboard Spider / False Widow Spider (Steatoda grossa), found under a manhole cover in my garden in SE London, 3rd May 2020.

7mm male Cupboard Spider / False Widow Spider (Steatoda grossa), found under a manhole cover in my garden in SE London, 3rd May 2020.

7mm male Cupboard Spider / False Widow Spider (Steatoda grossa), found under a manhole cover in my garden in SE London, 3rd May 2020.

Adult female Steatoda paykulliana

Mediterranean False Widow Spider   (Steatoda paykulliana)

Another of the False Widow species sometimes found in the UK, with a body-length of around 15mm and a leg-span of up to 35mm.

Steatoda paykulliana is a new species from the Mediterranean that sometimes finds its way to the UK in amongst grapes and other fruit. At the moment this species has only been found living wild in areas around Plymouth and Tilbury Docks in Essex. 

Adult female False Widow Spider   (Steatoda paykulliana)

This female specimen is unusually skinny due to it having just produced and egg-sac, which it was guarding when I found it under a large rock (not in the UK). These spiders can have a red, yellow or white band around the abdomen.

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Tangle Web Spider - (Steatoda / Asagena phalerata)
Since being reclassified from the Steatoda genus to the Asagena genus the Tangle Web Spider is no longer really a False Widow Spider. This uncommon species is small with a maximum body-length of less than 6mm. It is usually found in dry sunny places with little vegetation and sand dunes in the vicinity of ants, which form most of its diet.  rarely uses any silk to catch and subdue its ant-prey suggesting that its venom is highly effective on ants.

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