Orb-weaver spiders are members of the spider family Araneidae. They are the most common group of builders of spiral wheel-shaped webs often found in gardens, fields, and forests. The English word "orb" can mean "circular", hence the English name of the group. Araneids have eight similar eyes, hairy or spiny legs, and no stridulating organs.
Gasteracantha is a genus of orb-weaver spiders first named by Carl Jakob Sundevall in 1833. Species of the genus are known as spiny-backed orb-weavers, spiny orb-weavers, or spiny spiders. The females of most species are brightly colored with six prominent spines on their broad, hardened, shell-like abdomens. The name Gasteracantha is derived from the Greek gaster (γαστήρ), meaning "belly, abdomen", and akantha (άκανθα), meaning "thorn, spine". Spiny-backed orb-weavers are sometimes colloquially called "crab spiders" because of their shape, but they are not closely related to the true crab spiders. Other colloquial names for certain species include thorn spider, star spider, kite spider, or jewel spider.
A stabilimentum, also known as a web decoration, is a conspicuous silk structure included in the webs of some species of orb-web spider. Its function is a subject of debate.
Argiope keyserlingi is a species of orb-web spider found on the east coast of Australia, from Victoria to northern Queensland. It is very similar in appearance to a closely related north Queensland species, Argiope aetherea. A. keyserlingi is commonly found in large populations in suburban parks and gardens, particularly among the leaves of Lomandra longifolia. Like many species of orb-web spider, A. keyserlingi shows considerable sexual dimorphism, as the females are many times larger than the males. Mature females can be seen during the summer, and seeing multiple males on the web of one female is not uncommon.
Argiope aetherea is a common, large orb-web spider. Like other species of Argiope, it is commonly known as the St Andrew's Cross spider, due to the characteristic cross-shaped web decorations female spiders often include in their webs. A. aetherea is similar in appearance to A. keyserlingi, however female A. aetherea are generally larger than A. keyserlingi. Like most orb-web spiders, A. aetherea shows considerable sexual size dimorphism, with females being many times larger than males.
Argiope picta is a species of orb web spider found in tropical areas of Queensland, Australia and Papua New Guinea up to the Moluccas. This species is similar in size to the sympatric Argiope aetherea; females can be distinguished from those of A. aetherea via extensive differences in abdominal colouration and patterns. The males of these two species are almost indistinguishable.
Argyrodes, also called dewdrop spiders, is a genus of comb-footed spiders that was first described by Eugène Louis Simon in 1864. They occur worldwide, and are best known for their kleptoparasitism. They can spin their own webs, but tend to invade and reside in their hosts' webs. This relationship can be commensal or even mutual if the dewdrop spider feeds on small trapped insects that are not eaten by the host. Some species can even prey upon the host.
Ordgarius is a genus of orb-weaver spiders first described by Eugen von Keyserling in 1886. Adult females of the genus are bolas spiders, capturing their prey with one or more sticky drops at the end of a single line of silk rather than in a web. Males and juvenile females capture their prey directly with their legs.
Cyclosa, also called trashline orbweavers, is a genus of orb-weaver spiders first described by Anton Menge in 1866. Widely distributed worldwide, spiders of the genus Cyclosa build relatively small orb webs with a web decoration. The web decoration in Cyclosa spiders is often linear and includes prey remains and other debris, which probably serve to camouflage the spider. The name "Cyclosa" comes from Greek 'to move in a circle', referring to how it spins its web.
Neoscona, known as spotted orb-weavers and barn spiders, is a genus of orb-weaver spiders (Araneidae) first described by Eugène Simon in 1895 to separate these from other araneids in the now obsolete genus Epeira. The name Neoscona was derived from the Greek νέω, meaning "spin", and σχοῖνος, meaning "reed" They have a mostly pantropical distribution and one species, Neoscona adianta, has a palearctic distribution. As of April 2019 there are eight species that can be found in the United States and Canada:
Cyrtophora, the tent-web spiders, is a genus of orb-weaver spiders first described by Eugène Simon in 1895. Although they are in the "orb weaver" family, they do not build orb webs. Their tent-like, highly complex non-sticky web is sometimes considered a precursor of the simplified orb web. These webs are aligned horizontally, with a network of supporting threads above them. These spiders often live in colonies. Females have a body length of mostly about 10 millimetres (0.39 in) long. Some members, including Cyrtophora cicatrosa, exhibit the ability to change colour rapidly.
Micrathena, known as spiny orbweavers, is a genus of orb-weaver spiders first described by Carl Jakob Sundevall in 1833. Micrathena contains more than a hundred species, most of them Neotropical woodland-dwelling species. The name is derived from the Greek "micro", meaning "small", and the goddess Athena.
Argiope argentata, commonly known as the silver argiope or silver garden spider due to the silvery color of its cephalothorax, is a member of the orb-weaver spider family Araneidae. This species resides in arid and warm environments in North America, Central America, the Caribbean and widely across South America. In the United States, it is found at least in Southern California, Florida, Arizona, and Texas. A. argentata create stabilimenta and a unique zig-zag in its web design, and it utilizes its UV-reflecting silk to attract pollinating species to prey upon. Like other species of Argiope, its venom is not harmful to humans; however, it can be employed to immobilize its prey. A. argentata engages in sexual cannibalism either mid- or post-copulation. One aspect of particular interest regarding this species is its extinction patterns, which notably have minimal correlation with its population size but rather occur sporadically for the species.
Tetragnatha is a genus of long-jawed orb-weavers found all over the world. It was first described by Pierre André Latreille in 1804, and it contains hundreds of species. Most occur in the tropics and subtropics, and many can run over water. They are commonly called stretch spiders in reference to their elongated body form and their ability to hide on blades of grass or similar elongated substrates by stretching their front legs forward and the others behind them. The name Tetragnatha is derived from Greek, tetra- a numerical prefix referring to four and gnatha meaning "jaw". Evolution to cursorial behavior occurred long ago in a few different species, the most studied being those found on the Hawaiian islands. One of the biggest and most common species is T. extensa, which has a holarctic distribution. It can be found near lakes, river banks or swamps. Large numbers of individuals can often be found in reeds, tall grass, and around minor trees and shrubs.
Argiope protensa, commonly known as the tailed grass spider or teardrop spider, is a species of spider in the orb weaver family, Araneidae. This species is fairly common and widespread in Australasia, but like many spider species, little is known of its ecology, biology, or life history.
Argiope catenulata, also known as the grass cross spider, is a species of orb-weaver spiders ranging from India to the Philippines and Papua New Guinea, and also found in Australia in 2019. Like other species of the same genus, it builds a web with a zig-zag stabilimentum.
Argiope magnifica is a species of orb web spider found in tropical areas of north-east Queensland, Australia, eastern Papua New Guinea and the Solomon Islands. It is commonly known as the magnificent St Andrew's cross spider. This species is similar in size to the sympatric Argiope keyserlingi; females can be distinguished from those of A. keyserlingi via extensive differences in abdominal colouration and patterns. The males of these two species are almost indistinguishable.
