Identifying false widow spiders

The false widow spiders (Steatoda spp.) form a group of species that, because of their general resemblance to the much more notorious black widow spiders (Latrodectus spp.), 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 false widow spiders that live in the UK (Steatoda nobilis, Steatoda grossa, Steatoda bipunctata, Steatoda albomaculata, Steatoda triangulosa and Asagena phalerata). There are six species of false widow spiders that live in the UK (Steatoda nobilis, Steatoda grossa, Steatoda bipunctata, Steatoda albomaculata, Steatoda triangulosa and Asagena phalerata). They are black or brown in colour, rotund, and small - growing up to about the size of a small finger-nail. The maximum body length of an adult female is 15 mm.

An additional species, Steatoda paykulliana, is an occasional import in fruit shipments.

What do false widow spiders look like?

Abdomen markings: All species have distinctive sets of markings on their abdomens (the rear part of the spider's body). They have a narrow white or lighter band around the front of the abdomen towards their head, with other markings that vary by species.

However, all of these markings can be variable, faded, or missing, especially in adult females.

Abdomen shape: Females have globular, shiny abdomens. Male abdomens are smaller and less rounded, but have clearer markings.

Webs: Their webs are a tangle of criss-cross threads which may become quite dense in the centre if left undisturbed.

Here are some details for the species most likely to be seen in the UK:

Noble false widow (Steatoda nobilis)

Size and appearance

• Female 8.5-14 mm
• Male: 7-10 mm

Always larger than S. bipunctata and usually larger than 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.

• View more examples of the noble false widow on the iNaturalist website.

Distribution and habitat

Introduced with bananas from the Canary Islands and Madeira, they are now well established in the southern counties and 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.

Cupboard spider (Steatoda grossa)

Size and appearance

• Females: 6.5-10 mm
• Males: 4-6 mm

Females of this species are usually darker than S. nobilis and 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 in S. nobilis and S. bipunctata.

• View more examples of the cupboard spider on the iNaturalist website.

Distribution and habitat

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.

Rabbit hutch spider(Steatoda bipunctata)

Size and appearance

• Female: 4.5-7 mm
• Male: 4-5 mm

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.

• View more examples of the rabbit hutch spider on the iNaturalist website.

Distribution and habitat

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.

Mediterranean false widow spider (Steatoda paykulliana)

Size and appearance

• Female: 8-13 mm
• Male: 4.5-6 mm

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.

• View more examples of the Mediterranean false widow on the iNaturalist website.

Distribution and habitat

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.

Other spiders mistaken for 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 are harmless to humans. Please follow the links for more information on these spiders.