Monday, February 15, 2010

The Batik Orb-weaver Nephila antipodiana




With a leg span of up to 6 inches and body length up to 1.5 inches, this is one of the largest orb-weavers in the world. The sight of such huge spider with a web of 1 meter in diameter can be intimidating for some people but otherwise would simply instill awe and admiration. Because of their large size and the fact that they live in even larger webs, meeting one of them is not really that difficult. The Nephila antipodiana is in fact a rather common spider in places of moderately high altitude and cool temperature.

Newly hatched N. antipodiana spiderlings. The nest is in between branches near the web.


A juvenile female.



A Nephila antipodiana following a successful moult.



This is a really big momma. I say that because the size of the female is much larger than the male. It is like comparing a goat and a full grown elephant, and I am not referring to the imported boer. In some webs the males can be seen lurking at the edges, feeding on smaller insects that got trapped but ignored by the female. He might have to compete with the cunning argyrodes, commonly known as dewdrop spiders, which also make a female nephila web as their dining hall.

The smaller male is trying to mate with the female below. Mating can take quite a while.


These little dewdrop spiders are easiest to be found in webs of larger spiders. Several argyrodes species have been found to make a living from looting a nephila’s web. Such behaviour is known as kleptoparatism and studies have indicated that a web with too many argyrodes can severely retard the growth of a nephila. The host sometimes chases them away but most of the time they got to the prey faster and cut part of the web silk away to mask the prey’s vibration. Although argyrodes is of similar size and can be of similar colours to the male nephila, both can be easily distinguished from the body shape where the latter has a flatter abdomen.

A matured male waiting at the edge of a female's web.


There are 2 other nephila species I have found in Malaysia- N. pilipes and N. kuhlii. The webs are almost similar except that N. antipodiana usually has a second or third screen web of slightly different mesh pattern and sort of curved away from the main web where the spider resides. Sometimes several nephila webs area attached together creating a complex of mega webs like a massive fortress. I have heard accounts of small forest birds being snared in such formidable structures.

The range of this spider is wide with records ranging from China to New Zealand. They make webs almost anywhere possible- between branches, telephone cables, open ceilings and fences. Because they are huge and look menacing, I imagine it can easily cause discomfort to most people whenever a nephila is seen nearby human habitat. The natural tendency of most human behaviour is to expel the spider or kill it. This is unnecessary as orb weavers are generally gentle spiders and does not attack human, however gruesome they may look. A population of nephila in any neighborhood will reduce several kinds of pest insects which have been shown in several studies related to biological control of crop pest. Their huge webs and the tendency to cluster create a formidable defense against medium and large flying insects. For the smaller flyers, the males and argyrodes will take care of them.

A female coming out from a moult.

Some time recently a group of people in Madagascar made a fabric out of the silk of a nephila species local to that region. It took 4 years to collect and weave an 11’ x 4’ textile from the extraction of a million spiders. By weight, spider silk is stronger than steel and can stretch up to 40% of its length without breaking. It is interesting to know the extent of spider silk in science and industry which scientist believe can lead to revolutionary materials. But unlike silk worms they cannot be raised in captivity without them cannibalizing one another.

9 comments:

  1. They make webs almost anywhere possible- between branches, telephone cables, open ceilings and fences.<----Imagine if they ruled the world, you'd see small children stuck in the webs as prey!

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  2. Interesting information about the dewdrop spiders. I really don't know if there are similar kleptoparasitic species in North America or not.

    Excellent spider photos!

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  3. I must say... it was impressive... next time i want to follow you... i want to learn what you know...
    email me...
    sarshiverson@yahoo.com

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