Orb-weaver spider

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Araneus

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Argiope (St Andrew's Cross spider)

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Dicrostichus

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Gasteracantha (Spiny orb-weavers)

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Larinia

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Mastophora

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Metepiera

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Micrathena

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Neoscona

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The orb-weaver spiders (family Araneidae) are the familiar builders of spiral wheel-shaped webs often found in gardens, fields and forests. The family is a large one, including over 2800 species in over 160 genera worldwide, making it the third largest known (behind Salticidae and Linyphiidae).

Related Topics:
Species - Genera - Salticidae - Linyphiidae

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Generally, orb-weaving spiders are three-clawed builders of flat webs with sticky spiral capture silk. The web has always been thought of as an engineering marvel. It is built by the spider starting with a line floated on the wind to another surface. The spider secures the line and then drops another line from the center, making a "Y". The rest of the scaffolding follows with the radii of non-sticky silk being constructed before the final spiral of sticky capture silk. The third claw is used to walk on the non-sticky part of the web. Characteristically the prey insect that blunders into the sticky lines is stunned by a quick bite and then wrapped in silk. If the prey is a venomous insect, such as a wasp, wrapping may precede biting.

Related Topics:
Webs - Silk - Insect - Venom

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Some "orb-weavers" do not build webs at all. Members of the genus Mastophora in the Americas and Dicrostichus in Australia produce sticky globules, which contain a pheromone analog. The globule is hung from a silken thread dangled by the spider from its front legs. The pheromone analog attracts male moths of only a few species. These get stuck on the globule and are reeled in to be eaten. Interestingly, both types of "bolas" spiders are highly camouflaged and difficult to locate.

Related Topics:
Australia - Pheromone

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The spiny orb-weaving spiders in the genus Gasteracantha and Micrathena look like plant seeds or thorns hanging in their orb-webs. Some species of Gasteracantha have very long horn-like spines protruding from their abdomens.

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One feature of the webs of some orb-weavers is the stabilimentum, a crisscross band of silk through the center 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. 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 center of the web.

Related Topics:
Stabilimentum - Camouflage

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Most araneid webs are vertical and the spiders usually hang with their "head' downward. A few webs, such as those of orb-weaver in the genus Metepiera have the orb hidden within a tangle space web. Some Metepiera are semi-social and live in communal webs. In Mexico such communal webs have been cut out of trees or bushes and used for living fly paper.

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