Orb-weaver Spider

Orb-weaver Spider

The "typical" orb-weaver spiders (family Araneidae) are the most common group of builders of spiral wheel shaped webs often found in gardens, fields and forests. Their common name is taken from the round shape of this typical web, and the taxon was formerly also referred to as the Orbiculariae.

Orb-weavers have eight similar eyes, legs hairy or spiny and no stridulating organs. The Araneidae family is cosmopolitan, including many well-known large or brightly colored garden spiders. There are 3,006 species in 168 genera worldwide, making Araneidae the third largest family of spiders known (behind Salticidae and Linyphiidae). The orb-weavers include over 10,000 species and make up about 25% of spider diversity.

However, orb-webs are also produced by members of other families. The large "golden" orb-weavers (Nephilidae) and the long-jawed orb weavers (Tetragnathidae) were formerly included in the Araneidae; they are indeed closely related to them, being part of superfamily Araneoidea. Their webs are similar to those of the typical orb-weavers, but tend to be less sophisticated and often have an irregular instead of a neat spiral arrangement of the prey-capturing threads. The cribellate or hackled orb-weavers (Uloboridae) belong to a distinct superfamily of the suborder Araneomorphae; their webs are often very sophisticated but Uloboridae use neither poison to kill their prey, nor sticky threads in their web, and probably evolved the orb structure independently. Uloboridae are cribellate, and their threads can be recognized by the fuzzy and dull appearance, which captures prey by a velcro-like mechanism. Even among the Araneoidea, the orb-webs may have evolved at least twice from the three-dimensional webs most common in this superfamily, as typically produced e.g. by tangle-web spiders (Theridiidae).