St Andrew's Cross Spider

Argiope keyserlingii

Family: Araneidae  ID: Karsch, 1878

Habitat and Biology
The St Andrew's Cross spider commonly builds its web amongst shrubs and other vegetation or against walls of buildings. It normally hangs upside down in the web with two paired legs placed along each arm of the cross. The silken cross may be used for strengthening the web, for camouflage or for enhancing prey catches. It has been shown that the cross reflects ultra-violet light which is particularly attractive to insects. Egg sacs are pear-shaped, green in colour and are suspended in nearby vegetation rather than in the web itself.

Male: Cephalothorax and legs brown; abdomen cream with a mottled brown pattern.
Female: Cephalothorax brown and covered with silky hairs. Abdomen with horizontal stripes of yellow and crimson brown, sometimes with pale spots on the brown stripes. Legs dark brown to black with a few yellowish bands.

Small-bodied with relatively long legs; often appears to have only four legs due to resting position in web. Male much smaller than female.

Body Length
Male: 4mm
Female: 20mm

Web type
Orb web with a cross of thick silk through its centre.

The bite of this spider is considered harmless or at most to cause a weak local reaction. Few bites have been recorded.