A few more notes on Autumn Spiders

Some people are worried that the spiders that start appearing in autumn are banded together into small gangs hell bent on mischief. That couldn’t be further from the truth, and the reason the numbers get smaller is largely due to the effects of these big spiders on each other. They are often extremely territorial, and in the photo below you can see a female being driven from her web in an old shed by another female of roughly the same size.

The Tegenaria on the left is still sitting in the extremities of her web, but the intruding spider on the right is much closer to the entrance, preventing her from returning.

The spider left her home and fled while the newcomer decided to set up camp, and made the fatal error of straying to close to a neighbouring False Widow (Steatoda nobilis) which made short work of her. Almost all spider species will prey on each other, and sometimes members of the same species (cannibalism) but it is important to realise that the difference between one spider species and another can be as vast as that between a human being and a cow or any other mammal, and maybe even more so.

A large and dark female False Widow, Steatoda nobilis, with a large House Spider as prey. Spiders are an important part of many spiders prey.

Despite the massive appearance of large Tegenaria duellica House Spiders (the legs would easily span the palm of my hand) the bodies are never quite so large as they appear to be. The largest House Spider I ever saw appeared to have an abdomen of three centimetres in length (an inch) but when I measured it accurately with a scientific ruler I was very surprised to discover its body measured exactly 23 centimetres. And, of course none of these species are the largest in Ireland. That honour falls to a much more impressive creature, the Raft Spider, Dolomedes, which lives in swamps and bogs and hunts frogs and small fish among many other things. When I get a good photo ( I have a bad one) I’ll post something about that very handsome monster.

7 thoughts on “A few more notes on Autumn Spiders”

  1. Hi Samuel.

    Behind our house backs onto a large mill pond and our garden and outbuildings are home to a multitude of spiders. Your posts have helped me identify some of them.

    Would you be able to identify this one? Could it be false widow, just wondering if its any threat to our son who plays in the garden.

    It spends the daytime hidden away in the corner of a patio door then comes out to the centre of it’s web around dusk where it seems to stay (and hunt) for a number of hours. The web is approx 40cm in diameter. It rushes to anything large that lands in its web. I’ve even seen it tackle large moths.

    It has pale speckles and 2 large eye like dots on the outer of its abdomen and 2 smaller pale dots on its underside.

    Apologies for the poor photos!

    http://i379.photobucket.com/albums/oo235/RS84/Garden/Spider2.jpg

    [IMG]http://i379.photobucket.com/albums/oo235/RS84/Garden/Spider2.jpg[/IMG]

    http://i379.photobucket.com/albums/oo235/RS84/Garden/Spider1.jpg

    [IMG]http://i379.photobucket.com/albums/oo235/RS84/Garden/Spider1.jpg[/IMG]

  2. Hi Aidan,

    Those are good photos. You’ll be glad to know your son is perfectly safe as it’s an orb-weaver. I would need to see it from the other side to be certain which kind, but it looks very like a Cross Spider from what I can see of it, although there are similar species. If you can get that shot I’d be happy to give you a positive id. Once the webs are the classic spider-web shape you’re fine. The False Widows are also known as “tangle-web” spiders because their webs have no obviously consistent shape, and are usually pitched horizontally with the spider moving along upside-down underneath the web.

    Sam

  3. It is indeed a Cross Spider. The classic pattern. It’s a female and she will get very big if she doesn’t get snatched by a bird or a bat beforehand. But perfectly safe, and very beautiful in the right light. If there’s a heavy dew tonight you will get a terrific photo of the web in the morning light.

    Thanks for contacting me, and best regards.
    Sam

  4. Hi Adrian,

    It’s good enough to see what it is, and it’s definitely a Steatoda nobilis False Widow. That one looks like a male and the fatter bodied one will be a female.The males are pretty big in this species.

    Sam

Leave a Reply

Your email address will not be published. Required fields are marked *