Zigzag Stabilimentum

When we first started gardening in Camps Bay, and everything was new, I was delighted to see a yellow spider web, with this zigzag. I was working in the Engineering and Science Library at the University of Cape Town. Synchronicity brought me that week’s Nature magazine with a cover article about cutting edge research.

Zigzag stabilimentum

The zigzag stitch is called a stabilimentum.
The spider’s mum taught him, after catching all that food, and collecting all that protein, and weaving that meticulous web – you need to be sensible and protect your investment. This spider has definitely been to one of Valeri’s textile art classes at http://mysmallcornishgarden.blogspot.com/2009/08/all-blogged-out.html

From http://en.wikipedia.org/wiki/Stabilimentum

There is much controversy surrounding the function of these structures, and it is likely that different species use it for different purposes. Some people believe that they provide protection to the spider by either camouflaging it or making it appear larger. Another theory is that they make the spider visible and therefore animals such as birds are less likely to damage the spider’s web. Originally the decorations were thought to stabilize the web (hence the term stabilimentum), but this is dismissed nowadays. One more recent theory is that web decorations attract prey by reflecting ultraviolet light. Light in the ultraviolet part of the spectrum is known to be attractive to many species of insects. Many other theories have also been proposed such as thermoregulation, stress, regulation of excess silk, or simple aesthetics. At least one variant has been observed to vibrate the web, while positioned in the stabilimentum, when approached by a body the size of a human. One theory has been put forward that the purpose of the stabilimentum is to attract the male of the species to the web when the female is ready to reproduce.

Garden orb-weaver with

Blue Emperor dragonfly Lunch

When I photographed the zigzag the little spider shot off in horror. But his big brother has caught one of the Ungardener’s beloved dragonflies – looks like a Blue Emperor – sirloin steak instead of the usual hamburgers!

Common or garden white daisy

And now for my niece, who has had enough with the spiders already - your common or garden hybrid marguerite white daisy bush (came from a small piece hacked off a bush at my mother’s retirement village). Paradise for yellow or white crab/flower spiders, waiting on their dinner table with knife and fork raised in readiness, for unwary bees or flies who become Lunch (see post from 24^th August).

You can also just see the yellow Clivia (more later) and our boma made of off cuts from discarded grapevines. Our neighbours tell us it makes wonderful coals for the braai (barbeque). As vegetarians and wildlife gardeners – this is our brush pile – snails hide and get eaten by tabakrolletjie snakes (see post from 4^th September), lizards sun themselves and can escape.

And two frustrated cats say crossly – I know it is in there!