silk spider

silk spider, any of the spiders of the genera Nephila and Trichonephila, so named because of the great strength of their silk and the golden color of their huge orb webs. These webs often measure 1 meter (about 3.3 feet) or more in diameter and are suspended between trees by guy lines. Most live in the warmer regions of the world.

Physical description and webs

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Like many spiders, silk spiders are sexually dimorphic, meaning males and females are different in appearance. The most eye-catching individuals are females, which are both larger in size and more colorful than their male counterparts. Adult females have a body length of 25 to 50 mm (1 to 2 inches) and long legs. Males are dwarfs, measuring only 4 to 6 mm (about 0.2 inch). As adults, they build no webs but rather live in the web of the female, where they are sometimes captured and eaten while attempting to mate. Juvenile silk spiders build complete orbs, whereas the older ones construct only the bottom portion, which is frequently repaired but not rebuilt every day, as in the case of most other orb weaver spiders.

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Major species

Among the largest known silk spiders are females of Nephila komaci, a species reported in 2009 from specimens found in Africa and Madagascar that has a leg span measuring some 12 cm (4.7 inches). The banded legged golden orb-web spider (Nephila senegalensis) is found throughout much of sub-Saharan Africa.

Another giant silk spider is the banana spider (Trichonephila clavipes), a species found in the southeastern United States and in regions of Central and South America. Females of N. clavipes can have a body length of more than 40 mm (1.6 inches) and a leg span of more than 125 mm (4.9 inches). It is sometimes confused with the introduced joro spider (Trichonephila clavata), native to Asia.