St Andrew's Cross Spider - Argiope Keyserlingi

FAMILY ARANEIDAE

This page contains pictures and information about St Andrew's Cross Spiders that we found in the Brisbane area, Queensland, Australia.

Leg to leg female 50mm, female adult

St Andrew's Cross spider is easily found in Brisbane bushes and backyard gardens. It is easily recognized by the pattern on its body and its web. The spider makes an orb web, in the middle it makes four thickened zigzag strips in the shape of a cross of 'X'. The spider then hangs head down with its legs pairs together over the cross. This is why it called St Andrew's cross spider. Adult females build vertical orb web about 1m in diameters. The spiders active both day and night. 

wpeB.jpg (34930 bytes)  wpe3.jpg (38218 bytes)

St Andrew's Cross spider and some other spiders make this zigzag band known as stabilimentum. The function is uncertain yet. Some believed that the zigzag is used as the sign to warn-off the larger animals. Some believed that it is to stabilize the web. Some suggested that it act as a sunshade. This is a typical type of question in Evolution, it may never have a proven answer. However, more than a single, or even all answers are correct.

wpe9.jpg (24966 bytes)  wpe6.jpg (33801 bytes)  
Leg to leg 20mm, elder young female

Sometimes, the St Andrew's Cross spider makes only one line.  Sometimes, not very often, the spider make two crosses.

wpe6.jpg (31513 bytes)  wpeB.jpg (17999 bytes)
Leg to leg 15mm, young female                               
 
From spring to mid summer we can found small spiders build web with circular stabilimentum on lower plants. Their orb web is about 30cm in diameter with circular stabilimentum, which make the web centre and the spider highly visible. They are young St Andrew's Cross Spiders. They are pale brown to creamy white in colour. As the spider grows the circular shape is gradually transformed into cross shape. 
 
wpe7.jpg (24111 bytes)  wpeA.jpg (40010 bytes)
 
Female St Andrew's Cross spiders are easily recognised by theirs yellow bands on its flattened abdomen, with reddish-brown and white dots. The patterns may be a little different for different individual. The young female spiders are smaller in size, with same abdomen pattern although the colours are paler than the adult female.
 
wpe2.jpg (22464 bytes)  wpeF.jpg (23478 bytes)
Leg to leg 15mm, adult male                                  Male approaching a female

Adult male St Andrew's Cross spiders are smaller than the adult female. They have the relatively smaller abdomen, with no pattern on their abdomen. Both female and male St Andrew's Cross spiders have their hairy silver thorax and banded legs. All St Andrew's Cross spiders, including male, young and matured female, rest with legs in pairs.

wpe6.jpg (19277 bytes)

We sometimes found male St Andrew's Cross spider with some of its legs loss. Like this male only four legs left. We believe he was just mate with a female. Although he was lucky enough to escape after mating, half of its limbs were broken.

wpeF.jpg (32672 bytes)  wpe6.jpg (29120 bytes)
A closer look at the silk spinnerents of St Andrew's Cross spider. Sometimes the spider build really big cross. When disturbed, the spider will either temporary drop to the ground (bungee jump with safety line) from the web or shaking its web vigorously.
 
wpeF.jpg (23804 bytes)  

St Andrew's Cross spiders build vertical orb webs. The adult female build the web about half a meter to one meter in diameter, usually 1-2 meters about ground. Some orb web spiders, such as the Garden Orb Web Spiders, only set up their web at night, but the St Andrew's Cross spiders set up their web and 24 hrs standby. However, they usually rebuild their web at mid-night if necessary. In day time St Andrew's Cross spiders usually only repair (at minimum level) their webs if damaged.  

 
  wpe9.jpg (42221 bytes)
 
The female lays her eggs in a silk sac which is close to her web, then she will extract some liquid and dye the eggs sac into dark green colour.
 
wpeD.jpg (24379 bytes)  wpe11.jpg (30007 bytes)  
 
Female makes her egg sacs on late summer to early winter. Usually a female can make three or more egg sacs.
 
wpe11.jpg (29823 bytes)  wpe7.jpg (47029 bytes) 
 
From late winter to early spring, the young St Andrew's Cross Spiders hatch from the egg sac. The young spiders will stay together outside the egg sac for a few days. Then they will climb to a highest point and 'gone with the wind' using the ballooning technique.
 
 
Ballooning - A way that many species of spider used for travelling, especially the young spiders. They hold a short length of silk which blowed by the wing current. If the wind is strong enough, the young spiders travel with the wind. By this way spiders can disturb very far away even within a generation.
 
For more information about how spiders use their silk, please visit this page
 
 

 UUp ] Garden Orb Web Spider ] Scorpion-tailed Spider ] Triangular Spider ] Tent Spider ] Russian Tent Spider ] [ St Andrew's Cross Spider ] Banded Orb-weaving Spider ] Two-spined Spider ] Bird-dropping Spider ] Jewel Spider ] Pan Spider ] Leaf Nesting Spider ]

Back to top.


Download large pictures in our Wallpaper web page.  Give us comments in our Guest Book, or send email to us. A great way to support us is to buy a CD from us. 
Last updated: February 26, 2005.