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October 02, 2007
Oh, what a golden web she weaves …
Posted by neil, at 11:05 AM
I associate Golden Orb-weaving spiders (Nephila pilipes (syn. maculata)) with the hot period leading up to the wet. Adult females are particularly impressive in their gigantism, which increases relative to the equator. The image on the left has a male on the female's abdomen.
They would appear to have a three-month life-cycle with an extraordinary growth rate in females; from ~1mm to full hand-span in six weeks.
Their webs are spectacular and so strong they can break the momentum of small birds and bats. I observed one spanning an expanse one night and was astonished to see a three dimensional film of silk (about 30mm in diameter) being played across currents, seemingly unaffected by gravity, to a tree some five-metres distant. The spider then pulled the film into a thread.
There seems to be two distinct morphs; the lighter-coloured variety being vastly out-numbered by the black and yellow variety. Each is viewed differently through the compound eyes of flying insects, producing different capture rates. At nightime, however, darkness is so complete that colour is of little relevance and different groups of flying/jumping insects abound. Nephilas can vary the strength and flexibility of their silk to meet the different challenges of crickets or flies.
They are eaten by cassowaries and most probably frogmouths.
Posted by neil at October 2, 2007 11:05 AM
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Comments
Don't think we don't read these Neil. We just don't want to debate you on the issue. Good stuff and keep them coming.
Posted by: Luke at October 2, 2007 08:34 PM
I wonder what chemistry the web is composed of?
As I have understood spider's webs can be used in some new technology....
Posted by: Ann Novek at October 2, 2007 08:42 PM
Interesting! Had I taken the photos, it would have been from several hundred yards away with a telephoto lens!
Posted by: Paul Biggs at October 3, 2007 02:01 AM
Hi Ann,
I believe that spider silk is made up of complex proteins with major amino acids including proline, glycine, and glutamine. It is the strongest material for its weight on the planet.
I was very interested to here about the commercial supply of GM spider silk through goats milk, but have not heard any more of its success: http://news.bbc.co.uk/1/hi/sci/tech/889951.stm
Posted by: Neil Hewett at October 3, 2007 05:54 AM
Hi
I have a number of the golden ord-weaver spiders in my garden they must be 10cm or more - do they harm humans? What benefit do they offer to the garden. My kids (7 and 5) are terrified of them - should I remove them?
Posted by: Rick at February 19, 2008 11:51 AM