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.
The Australian garden orb weaver spider is a very common species of spider with many variants in size, shape, and colour across the coastal and northern regions of Australia. They have very large abdomens when well-fed and exhibit a tremendous colour-range from off-white through tan, brown to almost black. They have a roughly leaf-shaped pattern on the top of their abdomen with a complex outline that is darker than the surrounding area. There may also be several whitish spots or one or more stripes. The spiders' cephalothoraxes (heads) and proximal leg segments are usually darker, mostly reddish or reddish brown. They are able to change their colour with each moult to better match the background upon which they rest during the day.
Nephila is a genus of araneomorph spiders noted for the impressive webs they weave. Nephila consists of numerous species found in warmer regions around the world, although some species formerly included in the genus have been moved to Trichonephila. They are commonly called golden silk orb-weavers, golden orb-weavers, giant wood spiders, or banana spiders.
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.
Micrathena gracilis is a spider in the family Araneidae (orb-weavers), commonly known as the spined micrathena or castleback orbweaver. This spider spins a moderately large and very tightly coiled web. The spiders themselves are small and can be found to be anywhere from 4.2 mm to 10.8 mm long. Its venom is harmless to humans. M. gracilis is unique in appearance due to its large spiky abdomen and black and white bodies. Certain spiders of this species can also display a yellow color on the sides of their bodies. These spiders can be seen most active during the end of the summer and beginning of fall. M. gracilis is diurnal and are rarely ever seen active at night.
Zygiella x-notata, sometimes known as the missing sector orb weaver or the silver-sided sector spider, is a spider species in the family Araneidae. They are solitary spiders, residing in daily spun orb webs. Z. x-notata is a member of the genus Zygiella, the orb-weaving spiders. The adult female is easily recognized by the characteristic leaf-like mark on her posterior opisthosoma, caudal to the yellow-brown cephalothorax.
Spider behavior refers to the range of behaviors and activities performed by spiders. Spiders are air-breathing arthropods that have eight legs and chelicerae with fangs that inject venom. They are the largest order of arachnids and rank seventh in total species diversity among all other groups of organisms which is reflected in their large diversity of behavior.
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.
Gasteracantha fornicata is a species of spiny orb-weavers found in Queensland Australia. It is similar in shape to Austracantha minax which was originally described as Gasteracantha minax. It was described by Johan Christian Fabricius in 1775, the first Australian species of spider to be named and classified.
Sexual cannibalism is when an animal, usually the female, cannibalizes its mate prior to, during, or after copulation. It is a trait observed in many arachnid orders, several insect and crustacean clades, gastropods, and some snake species. Several hypotheses to explain this seemingly paradoxical behavior have been proposed. The adaptive foraging hypothesis, aggressive spillover hypothesis and mistaken identity hypothesis are among the proposed hypotheses to explain how sexual cannibalism evolved. This behavior is believed to have evolved as a manifestation of sexual conflict, occurring when the reproductive interests of males and females differ. In many species that exhibit sexual cannibalism, the female consumes the male upon detection. Females of cannibalistic species are generally hostile and unwilling to mate; thus many males of these species have developed adaptive behaviors to counteract female aggression.
Cyrtophora citricola, also known as the tropical tent-web spider, is an orb-weaver spider in the family Araneidae. It is found in Asia, Africa, Australia, Costa Rica, Hispaniola, Colombia, and Southern Europe and in 2000, it was discovered in Florida. C. citricola differs from many of its close relatives due its ability to live in a wide variety of environments. In North America and South America, the spider has caused extensive damage to agricultural operations.
Darwin's bark spider is an orb-weaver spider that produces the largest known orb webs, ranging from 900 to 28,000 square centimetres, with bridge lines spanning up to 25 metres (82 ft). The spider was discovered in Madagascar in the Andasibe-Mantadia National Park in 2009. Its silk is the toughest biological material ever studied. Its tensile strength is 1.6 GPa. The species was named in honour of the naturalist Charles Darwin on November 24, 2009—precisely 150 years after the publication of The Origin of Species.
Cyclosa argenteoalba, in the trashline orbweavers genus, is a species of orb weaver in the spider family Araneidae. It is found in East Asia in the countries of China, Japan, and Korea. C. argenteoalba are diurnal, which means they are active during the day. Each individual has a unique appearance due to their differences in the ratio of black to silver coloring on their abdomen. Spiders with less silver coloring are better at catching prey, since the silver is bright and warns their prey. They catch their prey by waiting in the hub of their web until their prey is close enough to catch. Parasitic larvae are often found attached to C. argenteoalba, and the larvae are able to manipulate the spider's behavior. Females are on average 2 mm longer in size than males. During mating, female genital mutilation is common in order to increase the fitness of the male. On their webs, they often attach silk "decorations" that are thought to deter predators. Relocating to a different place to build a new web occurs frequently until they find a location with a significant amount of prey.
Argyrodes elevatus, commonly referred to as dew-drop spider, is part of the family Theridiidae that consists of more than 3,000 species. These spiders are most commonly found in subtropical and tropical regions in South and Central America, as well as southern regions of the United States. One of the key distinguishing characteristics of A. elevatus is its kleptoparasitic behavior through which it primarily procures food for survival. Typically 1 or 2 A. elevatus spiders preside in outer areas of webs built by other species of spiders, although it is possible for up to 45 spiders. There are two main mechanisms by which A. elevatus raid the hub of the host's web to steal insects preyed and wrapped by the host spider. A. elevatus follows an intricate course to the hub of the web to search for prey, using vibrational detection enhanced by laid out threads along the web to find and capture the insect. These spiders are highly efficient, with the theft lasting a maximum of 12 seconds and high success rates. This reliance on a host spider for food has led to adaptations in sleep schedules and alternate food sources to revolve around the host species activity. A. elevatus display a unique courtship routine in which male A. elevatus presents prey wrapped in silk as a nuptial gift to the female spider. The male spider approaches the female, carrying the nuptial gift on its chelicerae while communicating with a distinct courting vibration, followed by copulation. Approximately twenty-four hours after the A. elevatus courtship and copulation series of events, the female spider will lay one to two eggs on the outer regions of the host's web.
Tetragnatha versicolor is a species of long-jawed orb weaver in the spider family Tetragnathidae. It is found throughout North America, Canada, Central America, and Cuba, but are most common in the United States. T. versicolor is heavily concentrated in New England and the west coast in states like California and Washington. T. versicolor is considered a habitat generalist, and can thrive in many different environments. While they can be found in places like Grasslands, Wetlands, Forests, etc., they prefer dryer areas like normal trees and shrubs. Unlike other spiders in the genus Tetragnatha, T. versicolor will rarely reside near aquatic environments. T. versicolor will typically be colored dark yellow or pale orange and average around 5 mm for males and 6.5 mm for females in length, which is very small for a spider. They are much longer than they are wide, making them very distinct. In addition, T. versicolor can be distinguished from other spiders in Tetragnatha by the distinct separation of the anterior/posterior eyes and the appearance of their reproductive organs. As an orb weaver spider, T. versicolor creates a web to hunt for prey. It will wait at night for prey to stumble into its web and use vibrational signals throughout the web to sense trapped prey. In terms of mating behavior, T. versicolor lacks a distinct courting ritual and will mate with any others in the proximity. Mating behavior is heavily affected by female mating history. In terms of interactions with humans, the bite of T. versicolor is venomous, but not known to cause significant harm.
Mastophora hutchinsoni, also known as the American bolas spider, is a species of orb weaver in the genus Mastophora. The genus is distributed extensively throughout various subtropical geographical areas including Australia, South Africa, Oriental Asia, and the Americas and is not found in Europe. The hunting behavior of adult female M. hutchinsoni is unusual because they are bolas spiders. They mimic moth pheromones to attract male moths, and female M. hutchinsoni have evolved to alter their chemical release to target different moths. They then capture their prey with a sticky drop on the end of a silk line, resembling a bolas.
Argiope radon is a species of orb web spider native to Australia. It is found in tropical areas of the Northern Territory, Western Australia and Queensland. It is commonly known as the Northern St Andrew's cross spider.
Thomisus spectabilis, also known as the white crab spider or Australian crab spider, is a small spider found in Australia and far east Asia.
Metepeira incrassata, also known as the colonial orb-weaving spider, belongs to the spider family Araneidae and genus Metepeira. They are most famous for their social organization and group living behavior. They are generally found in tropical rainforest and agricultural sites in Mexico, and their habitats tend to be highly productive. Their group sizes are relatively larger than other colonial spiders, typically ranging from hundreds to thousands of individuals. 99% of the females are observed to participate in colonial living, generally with at least two other individuals. Because most M. incrassata females are communal, the colonies are often dominated by larger males. There is minimal sexual dimorphism observed in M. incrassata. Unlike other orb-weaver spiders, M. incrassata builds a colonial web by connecting each spider's individual webs together through semi-permanent framelines. These colonial webs of M. incrassata are prone to invasion by kleptoparasitic and araneophagic spiders such as the Theridiidae family. The reproductive cycle of M. incrassata occurs throughout the entire year, with multiple generations sharing the same time period. Within their colonies, M. incrassata is seen to change locations. Larger, fertile females with egg sacs prefer to reside in the central area of the group for increased protection from predators, while the younger spiders are mostly found in peripheral positions. Larger adult M. incrassata are also known to finish web-building earlier than smaller ones, gaining an advantage in strategically positioning themselves.
Cyrtarachninae is a subfamily of spiders in the family Araneidae. The group has been circumscribed in several different ways. It originated as the group Cyrtarachneae, described by Eugène Simon in 1892. The group was later treated at different ranks: as a tribe, both under Simon's name and as Cyrtarachnini, and as the subfamily Cyrtarachninae. Circumscriptions have varied. The broadest circumscription, Cyrtarachninae sensu lato (s.l.), includes three of Simon's original groups, including the bolas spiders. Unlike most araneids, members of the subfamily do not construct orb webs, some not using webs at all to capture prey, some using one or more sticky drops on a single line, while others construct webs with few widely spaced non-spiral threads, some triangular. Many have been shown to attract prey by producing analogues of insect sex pheromones, particularly to attract male moths. Adult females may mimic snails, bird droppings and other objects, and so are able to remain exposed during the day time, capturing prey at night.
