As recently as three years ago the gardens of friends and neighbours in the South Peninsula of Cape Town were suddenly host to a different garden spider with a truly impressive layered golden web. The newcomer is the Golden Orb-web Spider (Nephila fenestra). While they are indigenous to the Western Cape, until a few years ago Golden orb web spiders were only found east of the Overberg. Apparently by the late 1990s, they had made their way to Sir Lowry’s Pass and are now fairly common throughout the South Peninsula. They favour trees and tall shrubs but also use buildings to anchor their huge webs. I find it amazing – almost a mystery – the way a creature the size of a spider can populate a new and vast area in a relatively short time. What are the advantages for them? It can’t be the proverbial Bright City Lights as they are most active in the day!!
The Golden Orb-web Spider (Nephila fenestra) is one of the three largest spiders occurring in our gardens in the South Peninsula of Cape Town. While their large size may be off putting, they are neither venomous nor aggressive. The other two large spiders are the Garden Spider (Argiope australis) also an orb web spider and the Rain Spider (Palystes castaneus) which does not make a web but prefers to hunt on the run. All these large garden spiders add interest to our urban habitat, and `pay’ their way by catching a variety of insects, many of which gardeners consider to be pests.
Webs that inspire both horror movies and silk garments!
The Golden Orb-web Spiders (Nephila fenestra) look rather scary with their large circumference and long black bottle brush legs. Their most impressive feature is the size of their golden webs which can span spaces between trees many meters wide and are also layers deep. In areas where their population density is high, they are semi-sociable and join webs to form seemingly impenetrable curtains. Certainly the fear factor of walking into these huge webs must be high and inspires horror movies. But these spiders are not venomous – so scary and dangerous are not necessarily related in the world of spiders. The genus name, Nephila, for the Golden Orb Web spiders comes from the Greek words “nen” (love) and “philos” (spin) and translates as a “love of spinning”. Simon Peers and Nicholas Godley took the Nephila literally and engaged 80 Madagascans to harvest silk from an estimated million female golden Orb Web spiders for 7 years. They produced an exquisite golden shawl, the largest garment ever made of spider silk. See the photo on the RHS and read the full story at http://news.bbc.co.uk/today/hi/today/newsid_9674000/9674949.stm
Unaware of the fame of her Madagascan cousins, a golden orb web spider has spun her web in my garden and already has a mate sharing it with her. The male is diminutive, a fraction of her size. See the photo on the LHS. The brownmale is in the right hand corner. While his relatively small size should be daunting enough, the male golden orb web spider knows that to father young, he has to mate with a cannibal. To avoid going from dishy to dinner, he presents her with a silk wrapped food parcel and mates with her while she is preoccupied with eating it!!
The more she eats, the larger she gets which inevitably results in her having to shed her exoskeleton. Spiders have a hardened `skin’ which acts like an external skeleton. This means that they have to moult periodically in order to grow. Our female did just that – somehow managing to extract her long delicate legs intact from their old leggings. .
Golden orb web spiders maybe top predators in the insect world of our gardens, but they don’t have it all their own way. Hadedas and guinea fowl, which ironically are also immigrants to the Cape either havebeen seen plucking large female spiders from their nests and eating them.
KimK 11 March 2012