G7386, Revised March 2003
Orb weavers (Araneidae) are often brightly colored with rounded abdomens, some with peculiarly angled humps or spines. However, there is considerable variation in size, color and shape in this group. They are often recognized for building beautiful, large, round webs, on which they rest, head downward, waiting for prey. The webs consist of a number of radiating threads crossed by two spirals. The inner spiral begins in the center, winds outward, and is made of smooth threads like the radiating threads. It covers only the central 1/3 of the web. The outer spiral begins at the edges and winds inward. It is made of more elastic, sticky threads, coated with a liquid substance.
One of the largest and most commonly encountered members of this group is Argiope aurantia, the yellow garden spider. It may cover an area 1.5 to 2.0 inches in diameter when at rest. The cephalothorax is silver and the oval abdomen has a yellow and black pattern. The legs are mostly black, blending to tan at the bases. The web contains a large zigzag band radiating out from the center. This spider feeds primarily on grasshoppers and katydids.
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