EPOW - Ecology Picture of the Week

Golden Orb Web Spider (Nephila sp., cf. N. maculata)
Family Araneidae (prev.) or Tetragnathidae (current)
Meghalaya, northeast India

Explanation:  Golden orb weavers (golden orb web spiders) are common in tropical and subtropical forests throughout the world.  This genus (Nephila) is particularly widespread, although only one species is found in the Western Hemisphere. 

This species (possibly Nephila maculata) was enjoying a warm afternoon in northeastern India, with its huge, strong web spanning two widely-spaced trees at least 2 meters (6 feet) apart.  

Here is the female, as the male is up to 1,000 times smaller and seems to live mostly for his genetic material and to maintain diversity of the gene pool.   This role of the male is so incredibly specialized in some Nephila species that, after mating, the male's copulatory organ will fragment, break off, and plug the female's genital opening, thus preventing her from mating with another male (Fromhage and Schneider 2006).  The female may then return the favor with cannibalistic fervor ... and consume her mate.  

Other spiders steal prey from orb weavers.  This behavior is called kleptoparasitism.  Common keptoparasites of orb weavers are theridiid spiders of the genus Argyrodes.  This versatile little sneak will variously collect small prey abandoned by orb weavers or outright steal their fresh captures, and even feed directly on the orb weaver eggs, juveniles, or adults (Koh and Li 2002).

Many people have used the web of golden orb weavers to make nets, traps, fishing lures, bandages, bird snares, and other items.  

On Palau, local legend refers to the man-spider Mangidabrudkoel who taught the lesson of moderation in use of natural resources.  It is thought that a species of Nephila spurred the basis for the legend.  

A more scientific lesson from golden orb weavers may be that they, as top invertebrate predators, could serve as important indicators of intact and healthy food webs in native environments.  
  

Information:
    Fromhage, L. and J. M Schneider.  2006.  Emasculation to plug up females: the significance of pedipalp damage in Nephila fenestrata.  Behavioral Ecology 17(3):353-357.
    Koh, T. H. and D. Li.  2002.  Population characteristics of a kleptoparasitic spider Argyrodes flavescens (Araenae: Theridiidae) and its impact on a host spider Nephila pilipes (Araneae: Tetragnathidae) from Singapore.  The Raffles Bulletin of Zoology 50(1):153-160.