Friday, January 16, 2009

St Andrew's Cross Spider

G’day,
We’ve got heaps of these around Mrs Gouldiae’s garden at present.


The St Andrew’s Cross spider is a beautiful species, or at least the female has a degree of beauty. The much smaller male is far plainer. The Argiope family of spiders is wide spread throughout the world. This Australian species, Argiope keyserlingi, is named in honour of Dr Keyserling, an early student of Australian spiders.

The common name, St Andrew’s Cross, is given because of the odd habit of the species weaving an orb web with a silky cross pattern at the centre. The purpose of the ‘cross’ is a bit unclear. Some research attributes it to attracting prey, small insects, beetles etc. Other sources believe the cross is designed to ward off larger species. It may be a camouflage strategy or perhaps a strengthening feature of the web. Apparently the cross part will reflect ultra violet light.


Normally, the spider hangs upside down in the centre of its web, with two adjacent legs held close together and aligned along each arm of the cross. How strange?

Unlike the Garden Orb Spider that weaves a new web each night, the St Andrew’s Cross Spider has a fixed web that it uses for some considerable time. Usually it is placed less than a couple of metres above the ground in relatively dense vegetation.

St Andrew’s Cross spiders are basically harmless to humans. They prey on small insects that might stumble into their web. Usually they wrap their prey in silk before delivering the fatal bite.
An exquisite addition to the garden.
Regards,
Gouldiae

9 comments:

  1. Hi Gouldiae
    Lovely Spider, well described.
    Didn't know about the UV bit, with the zig-zag stuff in the web.
    Cheers
    Denis

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  2. Very nice detailed spider photos. They do look interesting strung around the garden.

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  3. Great blog Gouldiae, and lovely photos.

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  4. If you've got any to spare Gouldiae, I'd like a few over here.

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  5. G'day All,
    Thanks for looking in.
    We do seem to have an abundance of them here right now. Might not be too many left tonight though, the wind here at present would blow a dog from its chain!
    Regards,
    Gouldiae

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  6. Interesting! And a rare case of being clear and lucid while at cross purposes ;-)

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  7. Nice pic's G. I'm not much on spiders, but she is a beauty.

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  8. Good one Tony!
    Thanks Dave, I doubt you'd have too many spiders in your garden at present.
    Regards,
    Gouldiae

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  9. hi Gouldiae,

    a beauty!

    I haven't seen any St Andrews Cross in my yard yet this summer, and in fact, there are many fewer orb spiders than is normal - very odd indeed.

    Cheers
    Gaye

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