Tag Archives: “Steatoda nobilis”

How to recognise a False Widow

The photo of Steatoda nobilis in the previous entry shows a female with the classic pattern of this species. However, here is the other, smaller False Widow, Steatoda grossa, which has a similar pattern, but with a row of triangles in the middle rather than a big pale patch.

A classic example of Steatoda grossa, a female.
A classic example of Steatoda grossa, a female.

So here are the best ways of recognising False Widows:

1. The spider’s abdomen is generally very shiny, like a berry. The spider is hairless.

2. False Widows don’t just hatch out of an egg fully grown. They can be very large, up to 2.5 cm (just short of an inch) when pregnant, and any size under that.

3. The web is a hammock-type web, but unlike the similar Hammock-web Spider, the web of the False Widow is EXTREMELY strong.

4. The spider always hangs upside down from its web.

5. Apart from the male Steatoda grossa, which is a fast runner often wandering into houses in spring (he doesn’t bite for some reason and will happily let you handle him) the female S. grossa and both male and female Steatoda nobilis are extremely slow and clumsy on the ground and actually slip when they walk on smooth surfaces.

6. The False Widow pulls its legs in tight, forming a ball, if knocked from its web or handled. Biting is the very last resort.

7. Both species have two very shiny eyes located at the top front of their heads which virtually glow in torchlight and are among the first things you will notice.

False Widows rest under crevices, usually only coming out at night when birds won’t see them. Birds have no difficulty eating any spider that will fit in their mouths. Anything resting against a wall, or in a sheltered area, or on the outside of a house especially under the eaves will be an attraction to a False Widow. They will enter sheds too, but outside if their preference.

8. False Widows are not afraid to be outside on even the coldest, frostiest nights. It was assumed, because they originate from the Canary Islands that they would fear the cold, but I have seen them outside in their webs when the temperatures were below freezing.

A big female Steatoda nobilis. This is one of the darker ones, with only a white crescent to the front of the big abdomen. They can be all black too, as can Steatoda grossa.
A big female Steatoda nobilis. This is one of the darker ones, with only a white crescent to the front of the big abdomen. They can be all black too, as can Steatoda grossa.

 

False Widows

A good few people have been in touch yesterday and today due to concerns over False Widow spiders being in Ireland.¬† I’m doing this post just to give you the facts. For anyone who is generally concerned about spiders and how to identify them, here is a link to my e-book about spiders, which you can download and read whether you own a kindle, or not, as it works on pc, laptop or Mac automatically when you download:

http://www.amazon.co.uk/Irish-Spiders-ebook/dp/B00ALJ8JTE/ref=sr_1_1?ie=UTF8&qid=1381702822&sr=8-1&keywords=sam+connolly+irish+spiders

A female Steatoda nobilis False Widow eating a woodlouse.
A female Steatoda nobilis False Widow eating a woodlouse.

Firstly, they’ve actually been recorded in Britain since the 1870s and here since the early 1980s. Firstly, they’ve been well established in Ireland since the 1990s. I found my first one in 1996. Secondly, they are called False Widows because they are not in the same genus as the true Widow spiders, but they are related. They are also much less venomous, and many False Widows are not venomous to man at all. They are virtually identical though, in size shape and colour.

Both Steatoda grossa and S. nobilis can be all black, looking identical to true Widow spiders. This one on my hand is an all black S. grossa.
Both Steatoda grossa and S. nobilis can be all black, looking identical to true Widow spiders. This one on my hand is an all black S. grossa.

False Widows also don’t actively bite and they don’t wander around very much either. They are not nearly as large as the House Spider, and are smooth rather than hairy. The body is the shape, size and texture of a black currant. I have frequently handled them and so far have never been bitten. However, if you are bitten the alkalic juice of the Dock leaf is very effective at neutralising the venom. Baking soda diluted in water is also very good but be careful as some people suffer burns to their skin from baking soda.

The bite my brother received when he accidentally crushed a False Widow beneath his hand. The spider lived, as did my brother. He described the pain as a numb ache that lasted about half-an-hour.
The bite my brother received when he accidentally crushed a False Widow beneath his hand. The spider lived, as did my brother. He described the pain as a numb ache that lasted about half-an-hour. I originally thought this might have been the bite of the Walnut Orb-weaver, an indigenous Irish spider which also delivers painful bites, as it was not quite as painful as we expected it should be. However, Trevor was 100% certain of his identification, and he knows his stuff.

Finally, the bite: the effects you suffer, if any, very much depend on your skin pH, and specific biology. My brother, Trevor, accidentally leaned on a False Widow when he rested against a bust stop bin while waiting for a bus a few years ago. It was a fully grown spider. Trevor says that the average bee-sting he has suffered was about twenty times more painful. However, some people could be allergic and suffer anaphylactic shock, but a peanut is potentially as much a threat to any person as a False Widow in that case.

Anyhow, the two most common spiders False Widows are confused with are the Missing-sector Orb-weaver  (Zygiella x-notata) and the Windowsill Spider (Amaurobius similis, both of which are very different to each other, but somewhat like False Widows.

 

A good treatment for False Widow venom

Ireland, like most of Europe has become home for species of spiders that can be venomous to human beings. Almost all spiders can potentially bite because all use venomous fangs to subdue prey, and sometimes defend themselves, but False Widows have a venom that has a bigger effect on people.

There are two species known in Ireland and both are believed to have originated in the Canary Islands and/or the nearby island of Madeira. However, these islands were stop-off points for trading ships travelling around the world in the Age of Discovery, from the 1480s onwards for ships rounding Africa or travelling to the Americans, so there is a small possibility they might actually have originated from elsewhere, but a this stage it’s highly likely we’ll never know for sure.

 

An average-size adult Steatoda grossa of the black variety, although the classically marked variety is beautiful by comparison. This spider looks very like a Black Widow or Australian Red-back Spider. However, none of these spiders is naturally aggressive and can be handled without biting, but care should always be taken.

Steatoda grossa, the smaller one, was first recorded in southern Ireland (and southern England) in the 1870s. Here is was largely confined for over a century but gradually spread northwards. Much later, in the early 1990s the larger Steatoda nobilis appeared, and it has spread all over the east coast and into the midlands now, where it is a very common species. False Widows are so-called because there are many species and most are completely harmless to humans, but they look almost identical to the true Widow spiders, the Latrodectids, such as the Black Widows, Brown Widow, White Widow, Australian Red-back Spider and New Zealand Katipo. There are actually MANY species and several are found in Europe, but not naturally in the British Isles or Scandinavia.

The irony is that of all the False Widow Spiders the two that have arrived in Britain and Ireland ARE mildly venomous to humans. But they are NOT aggressive spiders in any sense, and mostly like to be outside, although they do get into sheds and houses which do not have regular cleaning routines.

The venom of False Widows and Black Widows is a type of acid, so I hypothesised that cures and treatments used successfully on other acidic toxins, such as bee stings or nettles should also work with some degree of success on False Widow venom. Recently a friend was bitten by a small Steatoda grossa. The sting was quite powerful, but I’m happy to announce that treatment of the bite with crushed Dock leaf worked brilliantly and with almost immediate effect.

A leaf of Broad-leaved Dock photographed today...works great on nettle stings and False Widow bites. It SHOULD work on Black Widow bites too, as the venom is very close to that of False Widows. Baking Soda might work even better, but I haven't tested it yet.

Dock leaves can still be found outdoors in Ireland, but the frosts are starting to damage them. However, ordinary baking soda should also work to counteract the acid. HOWEVER, the Ph Balance in all human skin varies, so be careful as there are some people who could find their skin has a reaction to Baking Soda and to a lesser extent, Dock plants, although I’ve never encountered anyone with such problems. Paradoxically people who do have more acidic skin Ph will probably not suffer quite so much from acidic venom on their skin.

Always try treatments a little at a time, unless the pain is severe.

I plan to write more about False Widows soon, to help make identification easier, but there are few native Irish species like them. But do not be too worried because they are mainly outdoor spiders and the venom is not dangerous in its own right. The danger is that it could cause symptoms like other, more serious ailments. Mild muscle cramps in an area near the chest could cause someone with a heart problem, or their medic, to think they were in danger of cardiac arrest, so always record a bite or sting if you suffer one from any animal or plant no matter where in the world you happen to be when you suffer it.