Araneae: Araneidae: Argiope aurantia Lucas, 1833 (Golden Orb Weaver)

Large size ( a bady often over 1 in., or 25 mm long) and a black abdomen with broad yellow bars along the sides characterize the female of this spider. It is frequently seen hanging head down in the center of its large strong web. The web is constructed among shrubs and is of the orb type (like a wheel, with strands radiating out like spokes from the center and ringed with concentric circles of silk); below the center there is a zigzag band of silk (the stabilmentum) that apparently helps comouflage the spider, whose abdomen is similarly patterned. This spider and other orb weavers are sometimes called "writing spiders" because of the appearance fo the stabilmentum, which seems to some imaginative people to contain letters of the alphabet.

Photograph by C. Hogue

The male of the species, which is one-fourth the size of the female, lives inconspicuously in feeble imperfect web beside that of his mate. The Adults mature and mate in late summer. The female places her eggs in a large ovoid cocoon (3/4 in., or 20 mm, in diameter) that has a brown paper-like surface. The egg sac is suspended in a niche among leaves by a stiff web framework. The young hatch during the winter and remain in the cocoon untill the warm days of the following spring, when they escape and disperse.

The Golden Orb Weaver is also known as the Common Garden Spider and the Black and Yellow Argiope. Two other orb weavers in the genus Argiope are occasionally encountered locally. The Banded Orb Weaver (Argiope trifasciata) is similar to the Golden in shape, but its abdomen is cream with narrow circular black rings. The abdomen of another species, the Silver Orb Weaver (A. argentata), is flattened and strongly lobed posteriorly, and the carapace and front half of its abdomen are shiny silver.

All three Argiope species have similar habits; however, the Silver Orb Weaver constructs four stabilmenta, one at each point where the tips of the outstretched pairs of front and rear legs contact the web. All of these species are mature in the fall and can be seen in their conspicuous webs in August and September.

© 1993 Insects of the Los Angeles Basin