Most arachnid webs are vertical and the spiders usually hang with their head downward. They remain in their webs during the day and capture flies and other small insects. Humped Orb Weavers build small flimsy, horizontal webs among shrubs and grasses or over water. The band has been hypothesized to be a lure for prey, a marker to warn birds away from the web and a camouflage for the spider when it sits in the centre of the web. It is found in a number of genera, but Argiope, which includes the common garden spider of Europe as well as the yellow and banded garden spiders of North America, is a prime example. One feature of the webs of some orb-weavers is the ‘stabilimentum’, a crisscross band of silk through the centre of the web. Instead, they hunt by using a sticky ‘capture blob’ of silk on the end of a line) are highly camouflaged and difficult to locate. Interestingly, both types of bolas spiders (unusual orb-weaver spiders that have given up spinning the typical web. These get stuck on the globule and are reeled in to be eaten. The pheromone analog attracts male moths of only a few species. The globule hangs from a silken thread dangled by the spider from its front legs. Members of the genera Mastophora in the Americas, Cladomelea in Africa and Ordgarius in Australia produce sticky globules instead, which contain a pheromone analog (a chemical that triggers a natural behavioural response in another member of the same species). Some Orb Weaving spiders do not build webs at all. Some species of Orb Weaver spiders remain in their webs day and night. The rest of the web is then constructed before the final sticky capture spiral is woven into place. The spider secures the line and then drops another line from the centre, producing a ‘Y’ shape. The building of a web is an engineering feat, begun when the spider floats a line on the wind to another surface. Orb-weaving spiders are three-clawed builders of flat webs with sticky spiral capture silk. The abdomen often has rounded ‘shoulder’ humps that give these spiders their common name. They have long bodies and long limbs, with a body length of about 1 centimetre. Humped Orb Weavers or Silver Orb Weavers are easily recognised by their silvery body, with yellow or green and black markings. The main difference between the common Sydney species (Nephila plumipes) and Nephila edulis (which is more common in inland regions) is the presence of a ‘knob’ on the front of the sternum (the heart shaped plate on the underside of the body between the legs) of Nephila plumipes. The males are tiny measuring only 5 millimetres and red-brown to brown in color. Golden Orb Weavers are large spiders with a body length of 2 to 4 centimetres with silvery-grey to plum colored bodies and brown-black, often yellow banded legs. Orb Weaver Spiders sometimes have a dorsal stripe which may be white or brown edged with white. Most 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.

The commonly seen Garden Orb Weavers are 2 to 3 centimetres in length for the female and 1.5 to 2 centimetres for the male in body length. Orb Weaver Spider Characteristicsīecause there are so many different species of Orb Weavers, they differ in color shape and size. The oldest known orb-weaving spider is ‘Mesozygiella dunlopi’, an extinct species of orb-weaving spider with specimens found in amber dating from the Lower Cretaceous period. Orb Weaver Spiders This family of spiders is a very large one and includes over 2800 species in over 160 genera worldwide, making it the third largest family of spiders known behind the jumping spider family (Salticidae) and the second largest family of spiders called Linyphiidae commonly known as Sheet Weavers because of the shape of their webs.

Orb weaver spider