Gumtree Trunk Weaver - Argiope ocyaloides
FAMILY ARANEIDAE
This page contains pictures and information about Gumtree Weaver Spiders that we found in the Brisbane area, Queensland, Australia.
- Body length 15mm, female and egg-sac
- Most of those spiders are dark grey to black in colour, with white line along the sides of the long heart-shaped abdomen. Legs are all black with white ring. However, some are brown to pale brown in colours.
- This spider builds small size orb web against gum tree trunk. The web size is 200-300mm in diameter. As all other Argiope species, this spider rests on web with legs in pair. If we come closer, they vibrate the web very quickly and become almost invisible. Most of them are found on gum tree trunk with dark colour bark, such as the Ironbark gum trees or those gum trees with burnt bark.
- Like other species in this Argiope genus, young spiders build web with circular stabilimentum. Adult females build web without stabilimentum. We did not found any males yet.
- We noticed that this spider has one pair of eyes on the top of throax which are quite large (most web building spiders have very small eyes and some even cannot be seen). Those spiders may visually detects the prey coming closely, then vibrate their web to enhance the chance of entangle the prey.
Young Spider
- Same as the St Andrew's Cross Spider, the young spiders of this species build web with circular stabilimentum. They look exactly the same as the adult, of course smaller in size. Adults do not make those circular stabilimentum.
- The above young Gumtree Weaver was only 5mm in body length. When we came very close to look at it, it jumped onto the tree trunk from its small web and run away on the tree trunk surface,
Egg-sac
- Female with egg-sac Two egg-sacs, 10mm dia
- Females make disk-like egg-sac near their web. The egg-sacs are round and flattened with rough edges. They are pale brown in colour. They are usually 200mm away from the spider.
Other Colour Forms
- We sometimes found the pale brown and brown forms of this spider.
- Pale form on white tree trunk
- Most of the Gumtree Weaver Spiders are black in colour, but some times we found the reddish brown and pale brown forms. Usually they build web on tree trunk with colours match their body colours.
- Black form on white tree trunk Brown form on brown tree trunk
- Thank to Dr Volker W. Framenau for the identification of this spider.
- Reference:
- 1. Argiope ocyaloides ? - The Find-a-spider Guide for Australian Spiders, University of Southern Queensland, 2007.
