The spiders commonly known as false widow spiders belong to the scientific group Steatoda. Because of their general resemblance to the much more notorious black widow spiders (Latrodectus), they can cause concern when found in the UK.
Although they resemble black widow spiders, they are not as harmful. All these spiders are likely to do is give you a small and relatively harmless bite. (See our article How dangerous are false widow spiders?)
There are six species of spiders that live in the UK that are commonly referred to as false widow spiders. Five of these belong to the Steatoda group, along with one close relative:
Steatoda nobilis (the noble false widow)
Steatoda grossa (the cupboard spider)
Steatoda bipunctata (the rabbit hutch spider)
Steatoda albomaculata
Steatoda triangulosa
Asagena phalerata (Mediterranean false widow spider)
An additional species, Steatoda paykulliana, does not live in the UK but is found occasionally as an import in fruit shipments.
False widow spiders:
All false widow species have distinctive sets of markings on their abdomens. A key feature is a narrow crescent band around the front of their abdomen. Other patterns vary by species, but be aware that these markings can be variable, faded, or even missing, especially in adult females.
Female spiders have globular, shiny abdomens. Male spiders' abdomens are smaller and less rounded, but they generally have clearer markings.
Flase widow spider webs are a loose tangle of criss-cross threads which may become quite dense in the centre if left undisturbed.
Here are some details for the four species most likely to be seen in the UK.
A male (left) noble false widow and female (right). In some females, as in this example, the distinctive pattern on the abdomen can be faded. Notice how the female abdomen is more globular than the male. This is common to all false widow species. [male Steatoda nobilis image by Alvesgaspar licensed under CC BY-SA 3.0]
Noble false widows are always larger than the rabbit hutch spider (S. bipunctata) and usually larger than the cupboard spider (S. grossa).
Their abdomen pattern is often described as 'skull-shaped' but is more like a pentagon - it is clearer in males and dimmer or sometimes absent in females. Their legs are uniformly red to brown.
Noble false widows were introduced with bananas from the Canary Islands and Madeira. They are now well established in the southern counties and are spreading north. They are found in and around houses and other buildings.
They prefer elevated positions such as the top corners of rooms and conservatories, from where they hunt flying insects.
A male (left) cupboard spider and female (right). [male Steatoda grossa image by Algirdas licensed under CC BY-SA 3.0, female Steatoda grossa image by Dariusz Kowalczyk licensed under CC BY-SA 4.0]
Females of this species are usually darker than noble false widows (S. nobilis) and rabbit hutch spiders (S. bipunctata), with purplish-brown, evenly-coloured dark legs or with lighter stripes.
They have an abdomen pattern of two clear triangles and lateral bars, but these are often dim or missing in the darkest specimens. Both sexes have a lighter crescent on the front of the abdomen, but this is often absent too. Their front legs are longer than noble false widows and rabbit hutch spiders.
They are widespread in northern Europe and have colonised England, Wales and Ireland.
They are usually found in houses, but occasionally in sheltered spots outside and away from habitations. They prefer hidden areas near the ground under furniture, or dark low corners, from where they hunt for woodlice and crawling insects.
A female (left) rabbit hutch spider and male (right).[female Steatoda bipunctata image © M. Virtala, male Steatoda bipunctata image by Sanja565658 licensed under CC BY-SA 3.0]
This species has a light band that runs down the centre of their abdomen. As is usual with false widow species though, this is clearer in males, but fainter, partial or missing in females. The dark stripes on their legs are more visible than in the other false widow species.
Widespread and common in Britain and northern Europe. They mainly live in and around sheds, pet houses and clutter in gardens, but sometimes on tree trunks. They also frequent domestic rubbish which has been dumped illegally.
Steatoda paykulliana has abdomen patterns that can vary in colour: white, pale yellow, orange or red. [left image of Steatoda paykulliana on its eggs bag by Eitan Ferman licensed under CC BY-SA 3.0, right image of Steatoda paykulliana by Yaniv Kessler licensed under CC BY-SA 3.0]
This species have a black body and legs, with a characteristic midline pattern on their abdomen: triangles or chevrons running down the middle. Both these and the band at the front of the abdomen can be white, pale yellow, orange or red.
This species is so far not established in Britain, but is repeatedly imported with produce from the Mediterranean, especially with grapes. They hide in cracks in the ground and under stones.
The missing sector orb weaver (left) and the lace webbed spider (right) are often confused with false widow spiders.
Two species of spiders commonly found around UK homes and mistaken for false widows are the missing sector orb weaver (Zygiella x-notata) and the lace webbed spider (Amaurobius sp.). These spiders are harmless to humans.
They can be mistaken for false widows as they are a similar size and have rounded abdomens and markings that can look similar.
The missing sector orb weaver markings are silverly and its legs lighter in colour. It's webs are very different: unlike the false widow's tangle of threads, the missing sector orb weaver builds a classic orb web of concentric circles, but with one section missing.
Lace webbed spiders have matt, hairy abdomens, unlike the shiny ones of the false widow. They are also more oval and less rounded.
Please follow the links for more information on these spiders.
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