How to identify a false widow spider
It is thought to have a bite around the same power as a wasp sting, however, there have been bad reactions to its venom
False widows are the UK’s most venomous spider, and there are often reports of them in the early autumn.
A study from NUI Galway’s Ryan institute recently found that the venom from false widow spiders is 230 times stronger than native Irish spiders.
It is thought to have a bite around the same power as a wasp sting, however, there have been bad reactions to its venom.
There are three very similar species of false widow spider that are likely to be found in or around our homes:
What is a false widow spider?
Steatoda bipunctata
(known as the rabbit hutch spider),
Steatoda grossa
(known as the cupboard spider)
Steatoda nobilis
(known as the noble false widow).
“The noble false widow is the largest of these three species, with males typically growing to body lengths of up to 10mm and females up to 14mm.
Noble false widows are not native to the UK, but are thought to have arrived from the Canary Islands
The other two species are both native to the UK.
How do you identify one?
Firstly, they are mostly located in southern England, however this range is spreading north.
All species of false widow: “…have distinctive sets of markings on their abdomens:
they have a narrow white or lighter band around the front of the abdomen towards their head, and also other markings that vary by species.
However, all of these marks can be variable, faded, or missing, especially in adult females,”
“Females have a globular shiny abdomen, while male abdomens are smaller and less rounded, but are more clearly marked.”
The front section of a noble false widow’s “body is dark brown, as are the legs.
Female cupboard spiders “are usually darker than S. nobilis and S. bipunctata, with purplish-brown, evenly-coloured dark legs or with lighter stripes.
Both sexes have a lighter crescent on the front of the abdomen, but this is often absent too
Their front legs are longer that in S nobilis and S bipunctata.”
The dark stripes on their legs are more visible than in the other false widow species.”