False Widow can bite but is a non-aggressive spider
The False Widow has the distinction of being the only species of spider found in Ireland that has the ability to give people a painful bite.
It is a spider new to Ireland and is so named as, while it bears a superficial resemblance to them, it is not one of the 30 or so species that comprise the true widow spider group; it is a false version of the true widows.
Widow spiders get their name from the fact that females eat their partners immediately after mating thereby becoming widows. The males don't get a chance to play any hands-on role in parenting; their contribution to the next generation is to nourish their offspring's cannibalistic mothers in preparation for egg-laying.
The North American Black Widow is the best known of the true widow spiders. These shiny black spiders with red markings have an unusually potent venom and can inflict an extremely painful bite. Fortunately, bites to people are seldom fatal.
We have no widow spiders in Ireland. The False Widow bears a superficial resemblance to them and is the only spider we have in Ireland with jaws big enough to be capable of inflicting a bite to humans. On a scale of painfulness, the bite is rated as somewhat similar to the sting of a bee or wasp. Large females have a more venomous and more painful bite than the smaller males.
The False Widow is native to Madeira and the Canary Islands. It spread from there via shipments of fruits and vegetables, colonised mainland Spain and spread south to North Africa and north into France. Over time it reached the southern counties of England and later Ireland.
At present, the species is common in Dublin and has spread throughout urban areas in eastern and southern counties. Climate change and recent mild winters are believed to be aiding the spiders' spread westwards and northwards.
The False Widow is about the size of a 20c coin. The bulbous abdomen is dark brown in colour with cream coloured markings that have form a distinctive pattern; some see it as resembling a skull. The eight legs are reddish-orange.
The species has poor eyesight and is not aggressive, so it is unlikely to bite unless it is provoked or threated so it is best to give it a wide berth. As the traditional folk wisdom in the proverb advises us: 'If you want to live and thrive, let the spider run alive.'