Nephila maculatapilipes

  nephila 
  Originally uploaded by budak.

With a leg span of up to half a foot and fanged chelicerae that'd easily suck up the juice of soft flaccid ducks, the golden orb web spider, Nephila pilipes (maculata is apparently a junior synonym so the rules of zoological nomenclature demand that the older moniker bestowed by Fabrisius in 1793 takes precedence), is a big momma amongst webspinners, though still merely half the size of the freakshow scale goliath duck bird-eating  spider of tropical South America. Three families of spider, Araneidae, Uloboridae and Tetragnathidae (the latter was formerly recently split from Araneidae on account of their open rather than solid centre webs), build orb webs and these represent some of the most successful lineages of spiders after the jumpers (Salticidae) and sheetweb builders (Linyphiidae). Not all Araneids construct the orb webs synonymous with the order Araneae (and nor do all arachnids have spinnerets) but the assumed ability to extrude silk binds together spiders, mites, ticks, scorpions and harvestmen under a myth-inspired class that has engaged in a long armsrace with their six-legged arthropodal kin.

Within the family Tetragnathidae, the genus Nephila (subfamily Nephilinae) is pan-tropical, with members in both the old world and new. They build probably the largest known orb webs that reach over a metre in diameter and with threads strong enough to capture avian tetrapods. The webs are not fully symmetrical, with their lower halves covering a greater area than the upper. Smaller barrier webs may be positioned close to the main trap that prevent damage to the primary web from non-targeted animals such as birds. The two local species, N. pilipes and N. antipodiana (naturalist Joseph Lai has just found another species, the red-legged N. kuhlii, which does not seem to have been recorded earlier), typically place their webs at eye-level or higher and can be quite commonly found in the edge of secondary forests, well-planted gardens and less disturbed parks. As the webs are often strung up at gaps between trees and other natural landmarks, and frequently close to footpaths, it's surprising there has been no outcry against the existence of hand-sized vermin thriving so close to coddled children who cannot even be allowed to see the truth that's good for them. In some other lands, though, Nephila pilipes has acquired something of a totemic status, with its stylised silhouette adorning national icons the way aquatic chimera cats plague plastic bags and tourist traps on this isle.   

  nephila underside 
  Originally uploaded by budak.

The humongous creatures that sit at the hub of the webs are all ladies-in-waiting. After constructing their silken traps, they waste little energy safe the effort to rush a newly-entangled prey animal and deliver a bite of venom. Compared to their cousins the Argiope spiders, Nephila is reckoned to have a primitive prey capture strategy. With insects capable of releasing predator repellents, such as bombardier beetles and stink bugs, Nephila's approach of 'bite first and wrap later' triggers their defensive mechanisms, which can succeed in deterring the spider from continuing its assault and giving the insect an opportunity to free itself. Argiope, in contrast, quickly wraps prey animals in a cocoon of silk (which shields the spider from the insects' chemical secretions) before unleashing the fatal bite (source: Rainer F. Foelix, Biology of Spiders, Oxford University Press, 1996).      

Male Nephilas are minuscule creatures less than a centimetre long that hang around the web hoping that their consort will be more interested in making spider whoopee than treating them as snack food. In the same web can be found small reddish spiders (Argyrodes flavescens) that act as kleptoparasites, stealing bits of food from the landlady. She can probably afford a little largesse, given the number of hapless flyers her web is able to capture (the specimen I saw had a rich larder of fat winged termites). Nephila isn't always on top of the arthropod food chain, however. The neotropical N. clavipes is parasitised by wasps that lay an egg on the spider. The wasp grub in its final instar takes over the reins by instructing its host to build an atypical web thoroughly unsuited for prey capture but ideal as a cocoon for pupation. Thereafter the larva delivers the coup de grâce. A still but barely-alive husk of a smaller Nephila on a sliver of a web close by this fully grown adult suggests that the local species may be plagued by their own parasitoids. Non-virtual webs, too, are subject to the threat of remote takeover and manipulation by entities driven to zero sum replication.

Despite having a backbone (i think), my duck got featured in the Circus of the Spineless again! Check out the vomiting caterpillars, mighty millipedes and the slugs. Yesssh, especially the slugs....

Comments

[Snail]

What's not to love about Nephila? I remember driving across the Burdekin Bridge (in North Queensland) and seeing what seemed to be one Nephila every two or three metres. The steel girders made perfect scaffolding for their webs.

The common Argyrodes kleptoparasite in Australia is an exquisite, silvery spider that looks like a drop of mercury trapped on the threads.

[budak]

think the silvery spider should be this species: http://habitatnews.nus.edu.sg/guidebooks/spiders/text/Argyrodes_argentatus.htm

also updated the post with a possible new record by Joseph Koh (N. kuhlii) and N. pilipes' totemic status in Palau.

[Husky]

Interesting...

Looking through my film collection I have found a few taken between 1999 and 2001 which were identified as N.kuhlii - I thought they have always been around?