Orb or Wheel weaving spiders

Family Araneidae

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This is the family of spiders that makes the well-known orb-webs and are therefore called orb-weavers or wheel weaving spiders.
This family has recently undergone a lot of changes. The Nephila or golden orb web spiders, the Tetragnathidae or long jawed spiders are now described in their own family.
About 30 genera and 260 species have been recorded in Australia. the large Genus is Eriophora (=Araneus) with 110 species.
Well known spiders in this family are the Argiope or garden or St Andrew's cross spider, the curled leaf spider and the spiny (Christmas) spider.
None of these spiders are venomous to humans.

You do not suspect a spider in this wooly stick hanging in the air. But a closer look reveals the scorpion-tailed spider. The female spider is around 15 mm large and the male is almost invisible and is only 2-3 mm long. The colour differs markedly with age. From pinkish-brown, dark pink-orange-brown and dark-yellow.
The upper portion of the web often lack spirals. Spiderlings hatch in early summer. Their body starts triangular and lengthens with every mold. The spider can be found in in all states of Australia.

Arachnura higginsi Scorpion-tailed spider

The common name of these spiders is 'ambush' or' triangular' spider.
This triangular spider lives in open forest clearings along the East Coast amongst the foliage of shrubs and captures prey with the first two pairs of their heavily spined legs.

Nine species are described. They do no build a web. They are placed in the same family as the wheel-web weavers because of their body structure. The size of the female is about 9 mm, the male is only 5 mm.
The spider can be found on leaves, seed-heads and flowers. The egg-sacs are made in late summer and are spherical and pink-orange of colour.

Arkys cornutus by Michael Barrit

Arkys clavatus

Arkys ZZ452 WA by Wendy Eiby

This very well known spider is also known under the name 'garden spider'.
There are 25 known species in this genus but the most beautiful and spotted one is the Argiope Keyserlingi ( formerly aethera) or 'St Andrew's cross spider' and Argiope picta 'Northern St Andrew's cross spider'

The spiders of this family are easily identified by the zig-zag silk construction (stabilimentum), usually a cross, they make in their web. This in contrast to the in apprearance similar genus Gea that does not weave a zig-zag of silk in its orb web.
It is believed that the spider uses it to camouflage itself in the cross and to warn birds not to fly through the web.
But there are also other hypotheses.
Perhaps the most important function of stabilimenta is to attract insects. The silk of the stabilimentum reflects UV light and pollinating insects are lured to these threads.
If the spider is attacked it starts shaking vigorously in her web. The whole web becomes white because of the stabilimentum. This frightens of attackers.
The web is usually constructed a few decimeters above the ground in tall grass and among shrubs.

Argiope syrmatica and Argiope protensa are almost identical. The common name of Argiope protensa is tear-drop spider because of its elongated body ending in a point..

They are found between grasses. Thir webs sometimes have an irregular zig-zag of silk in the center of their web .

Argiope protensa QLD by Robert Whyte

Argiope ZZ307 Karinji NP WA

These spiders of around 5 - 13 mm are difficult to find. During day-time they rest on twigs. During the night they catch prey in orb webs with closely arranged spiral threads. The web can be 60 cm in diameter for Carepalxis coronata that lives north of Sydney up to Queensland. The spider breaks down her web in the morning.

This is a new described genus.

Celaenia excavata is better known as 'Bird-dropping' or 'Bird-dung' spider because it resembles it. An other common name is 'Orchard spider'.
The spider is 2 - 3 mm large and white, brown and cream of colour.
She does not make a web but attracts male moths of a single species ( Spodoptera mauritia, Lawn Armyworm ) by a special scent called pheromones. The pheromones are similar to the ones a female moth makes when she awaiting a man.

This orb-web spider that resembles the Arkys triangular spider.
Cyrtarachne is nocturnal and weaves a horizontal web. The sticky threads in the web of this genus are remarkably stronger than the viscid threads of the other araneids.

Cyrtarachne ZZ069

Eriophora circulissparsus
A pale green / yelow orb-web spider that is seldom noticed as it is a nocturnal spider. During the day it is well camouflaged againt leave surfaces. Males are 3-4 mm and females 5-7 mm.

Genus Ordgarius

Bolas spider

The bolas spider belongs to the famous set of Australian spiders, like the Sydney funnel web, the Red back and the jumping spider Portia.
These spiders became famous by the BBC series “Life in the undergrowth”.
Bolas is derived from the Spanish word ball (boleadorus) and is a throwing weapon. It consists of a rope with and a weight on the end of the rope.

The Bolas spider belongs to the family of orb weavers. But it does not make a orb web to catch prey but uses hís bolas instead. The Bolas spider also uses a rope, in this case a silken thread, and instead of a weight a sticky blob is attached at the end of the silken string.

Its prey is moths. To catch moths the spider releases moth specific pheromones – an odour, in this case three chemicals, that is released by the female moths to attract males. If a moth approaches, the spiders detects the vibration caused by the wing beats with its long sensitive hairs on its legs. It start swaying its bolas vividly in all direction below her. Moths attracted by the pheromones get glued to the sticky blob and are caught by the spider. By attracting only males with the pheromone the spider obviously does not catch female moths.

The spider is nocturnal like the moth it catches. During the day the spider hides in a web usually between one and two meters above the ground in scrub.
Females are 14 mm large while the males measure only 2 mm. The female makes several elongated egg-sacs containing dozens of eggs.

Three species occur in Australia mainly in NSW and QLD: Ordgarius magnificus, Ordgarius monstrosus and Ordgarius furcatus.

Magnificant spider

On the right Ordgarius magnificus hanging above it bolas thread. In the enlargement one can see there are smaller droplets of glue above the large 'bolas' droplet to maximize sticking of the moth to the thread.

Pictures by Greg Anderson

Heurodes ZZ302 (WA)

Heurodes (Acroaspis) is wide-spread in Australia and includes at least 15 or so species. However, species identification is currently impossible as the genus has not been taxonomically revised yet. The spiders look spectacular in their web at night. During the day, they motionless sit on a branch of a tree and cannot be distinguished from a little branch or bud. Birds will have a hard time finding these during the day.