San Diego Natural History Museum--Your Nature ConnectionSDNHM Field Guide
Argiope argentata, copyright Jim Berrian
Adult female

Argiope argentata
Silver Argiope

ARANEIDAE

Description

The total length of the female Silver Argiope measures up to 12mm. It has a silver carapace. The abdomen is silver with a pair of darker longitudinal bands and is ornamented with two pair of projections along the posterior margins. This spider's legs are silver with dark bands on tibia, metatarsi, and tarsi. The male is smaller and measures up to 4mm. In contrast to the female, the male's carapace is yellowish-white with two longitudinal, dorsal indistinct brownish bands. Legs have brown bands, and the abdomen is whitish with two longitudinal dark bands; the abdomen does not have paired projections.

Range and Habitat

The Silver Argiope occurs in southern California south to Baja California, as well as southern Florida, southern Texas, and southern Arizona ranging south to central Argentina. It is found in the coastal areas of San Diego.

This species is found on shrubs, in gardens, and in the wild. Several may be found on a single clump of prickly pear, Opuntia.

Natural History

Argiope are known for the construction of dense zigzag-shaped webbing called stabilimenta. There may be as many as four stabilimenta in a web. It is not uncommon to find the kleptoparasitic spider Argyroides in Argiope webs. In San Diego County these spiders are most often noticeable in late summer and fall.

Related and Similar Species

A very similar species is Argiope blanda. Females of the two species may be difficult to separate by color pattern. Reference to the genitalia is necessary to distinguish the species.

References

Levi, H.W. 1968. The spider genera Gea and Argiope in America (Araneae: Araneidae). Bull. Mus. Comp. Zool. 136(9):319-352.

Text by Jim Berrian. Photo © Jim Berrian.

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