08/10/18
Pest Of The Week – False Widow Spider

The false widow spiders belong to the genus, or group, called Steatoda. There are six species of Steatoda found in the UK including one introduced species, Steatoda nobilis. This group of spiders get their name because they look similar to the true black widow group of spiders, genus Latrodectus.

This species came from the Canary and Madeiran Islands over 100 years ago. It has been established in Devon for a long time but in recent years has been spreading along the south and east of England and is likely to spread northwards in years to come.

Sightings of the noble false widow spider continue to come from further afield, and it is likely that climate change, and the warmer winters this brings, has contributed to this spider’s continued colonisation of the UK.

Like the black widow spider, the noble false widow spider has a striking bulbous abdomen, but it is brownish in colour rather than pitch black, usually with distinctive cream markings and reddish-orangey legs. The females grow to 15mm.

They live in walls, fences and the barks of trees and eat insects, other invertebrates and even other spiders. False widow spiders do not make nests. Each individual makes a scaffold web with which it catches prey

It is probably the UK’s most venomous spider but bites are rare and usually result from handling the spider roughly or from a spider being trapped between clothing and skin. The severity of symptoms from any spider bite depends on the amount of venom that is injected. Bite symptoms are usually no more severe than a bee or wasp sting. More serious symptoms have occasionally been reported, but are likely to be the exceptional reaction of individuals to the venom. No one has ever died of a spider bite in the UK and the number of reported bites from spiders in general is minimal.

The popular media often picks up on reports of these spiders, probably because of the rather exotic sounding common name of ‘false widow spider’ as anything sounding like a ‘black widow’ causes a certain amount of excitement. This can sometimes create concern among members of the public, who worry about being bitten by a ‘widow spider’.

Generally one should avoid handling the spiders.

If you live in Scotland it is unlikely that you will see a False Widow Spider in your home. For further information visit the British Arachnological Society website.