Author Jess Price
Recently I discovered a false widow spider strolling across my bed. I knew it was a false widow as soon as I saw it. Smaller then a 1p piece, they have a distinctive globular shaped body and a glossy brown/black finish.
False widows are so called because of their general resemblance to the notorious black widow spiders. In fact false widows and true black widows belong in the same taxonomic family, the Theridiidae or comb-footed spiders. Luckily false widows are nowhere near as venomous.
There are six species of false widow spider that occur in the UK, but only three are commonly seen around houses; Steatoda grossa, S. bipunctata and S. nobilis. These species are synanthropic, which means they live near humans, benefiting from the artificial habitats we create such as sheds, garages, porches and conservatories.
These first two species are native and although they can bite, bites are not common. S. nobilis however, only arrived in the UK around 100 years ago and is reported to be more venomous. According to the Natural History Museum’s insect and spider identification and advisory service, S. nobilis
‘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’.
False widow bites are reported as usually being no worse than a bee or wasp sting. However some people can have a more severe reaction to S. nobilis including swelling and numbness so I was interested to know what species was on my bed.
The only accurate way to identify a spider is to look at the reproductive organs under a microscope. Not having one to hand, I sent photos to a Sussex-based spider expert and his best bet was an immature female S. grossa. The photos show three chevron type markings running down the middle of the abdomen which is typical but not exclusive to S. grossa. In mature females these often merge into a single large blotch and sometimes the markings become so dark that they are barely visible.
I like spiders. They are interesting and useful additions to a household, but I do object to one being on my bed. I can only assume that this female was looking for a new nesting site and had been lifted onto my bed on boxes that I had been sorting. S. grossa normally create tangled webs low down in the dark nooks and cracks of walls. I put her outside next to the shed so hopefully she’ll be able to find a suitable place for her web away from my bedroom.