Animal Species:Garden Orb Weaving Spiders

The Garden Orb Weaving Spiders are a large group of spiders with over 100 known species in Australia.

 

Garden Orb Spider, Eriophora sp.

Garden Orb Spider, Eriophora sp.
Mike Gray © Australian Museum

Alternative Name/s

Garden Orb Weavers

Number of species

100

Identification

The commonly seen Garden Orb Weavers are stout, reddish-brown or grey spiders with a leaf-shaped pattern on their fat, roughly triangular abdomens, which also have two noticeable humps towards the front. They sometimes have a dorsal stripe which may be white or brown edged with white.

Size range

2 cm - 3 cm (female), 1.5 cm - 2 cm (male)

Similar Species

Distribution

Orb weaving spiders are found throughout Australia. Common Garden Orb Weavers are Eriophora biapicata and E. transmarina from eastern and southern Australia.

Habitat

Orb weaving spiders make suspended, sticky, wheel-shaped orb webs. Webs are placed in openings between trees and shrubs where insects are likely to fly.

The Garden Orb Weavers build large, strong, vertical orb webs. Generally, the spider constructs its web in the evenings and takes it down again at dawn. The spider rests head-down in the centre of the web, waiting for prey.

Feeding and Diet

Garden Orb Weaving Spiders make wheel-shaped webs in openings between trees and shrubs where insects are likely to fly. When an insect flies into the web, the spider senses the vibration, rushes out from the web centre and rapidly wraps the victim in silk, rotating it with its shorter middle legs. When the prey is secure the orb-weaver administers a bite and sits back to allow the deadly venom to do its job. Once all movement has stopped, the spider takes the meal to the centre of the web and eats it or hangs it up for later. When food is plentiful these spiders will release large prey rather than risk a fight that may damage their web. Flying insects such as flies, beetles and bugs (including large prey like cicadas), are common prey. Butterflies and day-active moths are sometimes caught but are partially protected from web entrapment by the presence of scales on their wings - these scales can be shed and this may allow the insect to struggle free of the sticky web.

Other behaviours and adaptations

During the day, the spider rests on nearby foliage with its legs drawn under the body. 

Life cycle

The lifespan of a female Garden Orb Weaver is about twelve months. A female lays her eggs in late summer to autumn. The eggs are encased in a fluffy silken cocoon and attached to foliage. During autumn, the spiderlings hatch and disperse by ballooning (floating on the breeze using small silk strands as "balloons"), and build their own tiny orb webs among vegetation and wait out the winter. During spring the spiderlings start to develop more quickly and they mature in summer.  The cycle then begins again, the adult females mate and lay their eggs.  Adult females usually die off in autumn - early winter. Males and females are similar in size.

Predators, Parasites and Diseases

Birds such as honeyeaters are common predators of these spiders.

Danger to humans and first aid

Orb weavers are reluctant to bite. Symptoms are usually negligible or mild local pain, numbness and swelling. Occasionally nausea and dizziness can occur after a bite.

Seek medical attention if symptoms persist.

Classification

Species:
sp.
Genus:
Eriophora
Family:
Araneidae
Superfamily:
Araneoidea
Suborder:
Araneomorphae
Order:
Araneae
Class:
Arachnida
Phylum:
Arthropoda
Kingdom:
Animalia

What does this mean?

References

  • Simon-Brunet, B. 1994. The Silken Web: a natural history of Australian spiders. Reed Books.
  • York Main, B. 1976. Spiders. The Australian Naturalist Library, Collins.
  • Connell, N.T. 2001. Brood Cell Provisioning By Wasps Of The Family Sphecidae. Entomology 325, Cornell University http://ntc2.home.attbi.com/ent325term.html
  • Blackledge, T.A. and Pickett, K.M. 2000. Predatory Interactions Between Mud-Dauber Wasps (Hymenoptera, Sphecidae) and Argiope (Araneae, Araneidae) in Captivity. The Journal of Arachnology http://www.americanarachnology.org/JoA_tocs/JOA_v28n2.html#211


Dr Mike Gray
Last Updated:

Tags spiders, orb-weavers, orb-weaving, araneae, arachnida, invertebrates, classification, identification, orb webs,

5 comments

tuskfish - 10.03 AM, 23 March 2012
I am curious to know if garden orb spiders, by instinct, return to the same garden location year after year. I'm not suggesting that over successive years that it's the same spider, because I accept that they have a 12 month life cycle. I ask this because I only ever seen one garden orb spider in our yard (early autumn, in Albany Western Australia) on an annual basis over about five years. Once I relocated this one garden orb spider from my yard (because it was in an inconvenient location) to a neighbors more bushy yard, and while the relocation seemed successful for a week or two, invariably a garden orb spider would fill the same place / location left by the one I relocated. I then tried some back-yard science and placed a small dot of white paint on the top abdoment of the spider (at night when on it's web), then I relocated the spider. To my amazement, I found that after that week to two week absence - the same spider, with the white dot, returned to the same garden locale. I tried this several times and observed that the same (or what appears to be the same spider) retuned. It's 2012, the sixth year from whence I started watching one garden orb spider set up in the same inconvenient location in our front yard, year after year. Yes - it lays a silk egg sack on a brick wall near the gutter. - in also what appears to be the same spot every year (but I often brush it down and place it in the bin). I am just intrigued and left to wonder....
Toolin - 6.01 PM, 30 January 2012
We have a number in our garden that we love to see come out. Today, one showed behaviour I have never seen before. It was wrapping a catch up in silk and these little black flies were trying to get to the catch and were landing on the catch and the spider. The spider was aggressively swatting the flies away, espeically when they landed it. It would even turn around and swat them in the air. Eventually was satisfied with the wrapping and moved to the side of the web to watch them. Tried to video it but was all over before I got back with the camera.
echobee - 1.07 PM, 23 July 2011
We have quite a few of these in our garden during summer.. but I have noticed one spider (who has been fondly named "Rusty") who has gone into hiding over winter in an old leaf, and seems to be "hibernating" through our winter. Here is a photo I took of her the other day. I look forward to her waking up and hope she re-establishes her web.

Comment Attachment

Louise Carter - 3.05 PM, 11 May 2011

As we are coming into winter the spiders tend to die off so there wont be that many of them around.  Also it is possible to move the spiders to parts of the garden that are out of the way so you wont run into their webs.

barriews - 10.03 AM, 16 March 2011
I have 2 Spiders down the side path of my house, quite large the gold webs and the spiders are growing every day. They are attached also to my neighbours carport, so I know they can't stay there. We will have spiders running everywhere soon. They are so beautiful but ! Any ideas of who would want them. Port Stephens area.

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