Orb-weaving spiders

Families Araneidae, Nephilidae, Tetragnathidae, Theridiosomatidae, Anapidae

Orb-weavers are common spiders that usually take us by surprise. They make circular webs of very sticky silk that are often built across pathways at night and taken down at first light. 

Garden Orb Weaver, Araneidae, Eriophora transmarina Female Garden Orb Weaver, Araneidae, Eriophora transmarina, on a web.Although most make a simple circular web hung vertically, some make horizontal or sloped webs (Camel-backed spider, Leucauge granulata) and others make domed webs (Tent web spiders, Cyrtophora moluccensis) with massive superstructures of silk above an below the dome.

Most spiders are solitary, preferring to eat a fellow species rather than "socialising". However, most commonly in north Queensland but even sometimes around Brisbane, Tent web spiders form massive colonies, as big as a house, including in their margins other species like the Golden Orb.

Often hanging around the margins of orb webs are tiny Silver Dewdrop spiders (Argyrodes antipodiana). These are called kleptoparasites because they steal small parts of food from the host spider and even feed at the mouth of the host while she is feeding! They occur in all habitats but are most diverse along the coasts and are found throughout Australia. The families occur throughout the world.

Prey

Flying insects (mosquitoes, flies, beetles and bugs) are commonly taken in the webs, even when the spider is long dead. Rarely, the strong webs of the Golden Orb weavers trap small birds which may be killed to prevent further damage to the web.

Predators

Birds feed heavily upon these spiders but they are also taken by wasps that cut off the spiders' legs and allow their grubs to feed on the live spider.

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