National Geographic : 1971 Aug
ARANEUSTRIFOLIUM,TWICELIFE-SIZE, NORTHAMERICA;BYJANICEHEALEY ALCIMOSPHENUS BIFURCATUS,2 1/2 TIMESLIFE-SIZE, JAMAICA;BYJOHNA. L . COOKE Lurking lady of the meadows (top left), this shamrock spider normally stays hidden in a re treat of folded leaves positioned near her 21/2-foot-wide orb web. A taut trapline links hideout and snare. When an insect strikes, the trapline transmits the vibrations of its struggle from the web to the spider, who rushes in for the kill. Pear-shaped and berry-bright, this Jamaican orb weaver (above) displays apparel befit ting its tropical habitat. 212 GASTERACANTHA CANCRIFORMIS,2 1/2 TIMESLIFE-SIZE, TR PlAI ANDSIIRTROPICAL AMERICAS:BYJOHNA. L . COOKE World's strongest natural fibers form the web of the golden silk spider (above). Spider silk, once widely used for cross hairs in optical in struments, is finer, lighter, and tougher than silkworm thread. But the creatures' cannibalistic nature pre cludes raising them to pro duce silk for textiles. Birds get the point: Spiny backed spider, here upside down, wears pronged armor that discourages attackers.