Trichonephila clavipes

T. clavipes has the large size and the long legs with clumps of hair that are typical of the genus. It is large compared to most other members of the genus, and is distinguished by the bright colors of the female abdomen, which changes color as the spider matures.

As is usual among orb-weavers, marked sexual dimorphism occurs in general appearance, but especially in size; in linear measurements, males are one-third to one-quarter the size of females, and they also have a more slender build. This implies a mass some 1/30th to 1/70th of a large female.

Female ventral side

The specific epithet clavipes is derived from the Latin: clava, that variously may mean "knotted staff", "club", or "key"; and pēs meaning "of or pertaining to a foot".[2]
In assigning the name, Linnaeus apparently referred to the clumps of hair on the legs.

T. clavipes occurs most commonly in the Antilles and in Central America from Mexico in the north through Panama in the south. Less abundantly it occurs as far south as Argentina and in the north it occurs in parts of the southern states of the continental USA. Seasonally, it may range more widely; in summer, it may be found as far north as lower Eastern Canada. Beyond 40° N latitude, these spiders seldom survive the winter.

Because humans inadvertently transport spiders as passengers in cargo containers, plant nursery stock, and the like, T. clavipes generally occurs very unevenly over wide areas; often, patches of high local densities are found far from any other populations. Accidental human transport of the species increases markedly in late August to early September, when the spiders' reproduction is at its height.

The main web of a mature female may be as large as 1 m in diameter, not counting the main filaments that anchor the web between trees; such anchor filaments may be 2-3 m in length. A yellow pigment in the silk lends it a rich, golden glow in suitable lighting. Males come into the female's web for copulation and mate with her, while she is feeding and unable to attack them. After mating, the female spins an egg sac on a tree, laying hundreds of eggs in each sac.

The spider is not aggressive and only bites if handled roughly; the venom is relatively harmless and rarely causes more than slight redness and temporary localized pain.[3]

A single thread of the anchor silk has a tensile strength of 4×10⁹ N/m², which exceeds that of steel by a factor of eight (ultimate strength of steel 500x10⁶ N/m²).

The silk of T. clavipes has recently been investigated to evaluate its usefulness in surgically improving mammalian neuronal regeneration. In vitro experiments showed that a filament of the silk can lead a severed neuron through the body to the site from which it was severed. The silk elicits no reaction from the immune system, and thereby escapes rejection by the host body.[4]

Research at Iowa State University has shown that T. clavipes silk, specifically in the draglines, has exceptionally high thermal conductivity, exceeding that of most metals.[5]

• Borror, D. J. (1960). Dictionary of Word Roots and Combining Forms. Mayfield Publishing Company, 134 pp.
• Cameron, H. D. (2005). "An etymological dictionary of North American spider genus names", Chapter 73, page 73 in Ubick D., Paquin P., Cushing P. E. and Roth V. (eds.) Spiders of North America: an identification manual. American Arachnological Society, Keene (New Hampshire).

• Mating pair
• Pictures of T. clavipes (free for noncommercial use)
• Gravity favours smaller males : Review of scientific article on why males are much smaller than females

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