| Nuctenea umbratica | |
|---|---|
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Scientific classification  | |
| Domain: | Eukaryota |
| Kingdom: | Animalia |
| Phylum: | Arthropoda |
| Subphylum: | Chelicerata |
| Class: | Arachnida |
| Order: | Araneae |
| Infraorder: | Araneomorphae |
| Family: | Araneidae |
| Genus: | Nuctenea |
| Species: | N. umbratica |
| Binomial name | |
| Nuctenea umbratica | |
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| Synonyms | |
Araneus umbraticus Contents | |
Nuctenea umbratica, the walnut orb-weaver spider, is a species of spider in the family Araneidae.
The species name umbratica means "living in the shadows" in Latin.
The walnut orb-weaver spider is very wide and flattened, with a leathery skin. Its color ranges from red brown and grey brown to black, with a dark, yellowish to yellow-greenish leaf-like flecked marking on its opisthosoma, where small dents are visible. These are the onsets of muscles that flatten the abdomen.
Female N. umbratica can reach up to 15 mm in size; the males grow only up to 8 mm.
The spider hides during the day outside of buildings in wall crevices or under loose bark. They are very common in Central Europe; females occur all year, while males appear mostly during the summer. This spider has a flattened body, helping it to secrete itself in cracks and crevices. Walnut orb-weaving spiders are capable of concealing themselves in very confined spaces. This tends to act as a defensive advantage and increases the number of locations an orb-web can be effectively constructed.
In the evening the spider constructs an orb-web that can be up to 70 cm in diameter. A signaling thread leads from the web to her hiding place. After dusk she sits in the web's center.
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.
Austracantha is a genus of spider with a single species, Austracantha minax, commonly known as the jewel spider or the Christmas spider. It is a member of the family Araneidae and is endemic to Australia. They are relatively small spiders, reaching a maximum total body length of only around 12 mm (0.47 in) for females, and 5 mm (0.20 in) for males. Their abdomen has six distinctive projections ("spines") that makes them easy to identify. They are predominantly a shiny black, with variable white, yellow, and orange patterns. Melanistic forms also occur during autumn. They are facultatively gregarious, and can be found in large aggregations of overlapping orb webs. They feed on small flying insects that get entangled in their webs. They are harmless to humans, though the webs can be a nuisance for bushwalkers. They are most abundant during the summer months.
Araneus quadratus, the four-spot orb-weaver, is a common orb-weaver spider found in Europe and Central Asia, and as far as the Kamchatka Peninsula and Japan. Females can reach 17 mm in length, especially when gravid, with males around half that. They are quite variable in appearance, ranging from brown to bright orange or green, but they always have the characteristic four white spots on the abdomen. The darker color morphs are easier to identify, due to the contrast between the white spots and the rest of the body. The legs are sometimes brightly striped.
A bolas spider is a member of the orb-weaver spider that, instead of spinning a typical orb web, hunts by using one or more sticky "capture blobs" on the end of a silk line, known as a "bolas". By swinging the bolas at flying male moths or moth flies nearby, the spider may snag its prey rather like a fisherman snagging a fish on a hook. Because of this, they are also called angling or fishing spiders. The prey is lured to the spider by the production of up to three sex pheromone-analogues.
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.
Araneus is a genus of common orb-weaving spiders. It includes about 650 species, among which are the European garden spider and the barn spider. The genus was erected by Carl Alexander Clerck in 1757.
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 bruennichi is a species of orb-web spiders distributed throughout Central and Northern Europe, North Africa, parts of Asia, and the Azores archipelago. Like many other members of the genus Argiope, it has strikingly yellow and black markings on its abdomen.
Nuctenea is a genus of orb-weaver spiders first described by Eugène Simon in 1895. Its most familiar member is the Walnut Orb-Weaver Spider, N. umbratica.
Larinioides sclopetarius, commonly called bridge-spider or gray cross-spider, is a relatively large orb-weaver spider with Holarctic distribution. These spiders originated in Europe, have been observed as south as the Mediterranean Coast and as north as Finland, and have been introduced to North America. They are often found on bridges, especially near light and over water. The species tends to live on steel objects and is seldom seen on vegetation. Females reach a body length of 10–14mm, and males 8–9mm. Their orb webs can have diameters of up to 70 cm.
Gasteracantha cancriformis is a species of orb-weaver spider. It is widely distributed in the New World.
Kaira, sometimes called frilled orbweavers, is a mostly neotropical genus of orb-weaver spiders first described by O. Pickard-Cambridge in 1889. It includes sixteen described species that occur from South America up to the southern and eastern USA. It is presumably related to Aculepeira, Amazonepeira and Metepeira.
Argiope anasuja, is a species of harmless orb-weaver spider found from the Seychelles to India, Pakistan and Sri Lanka, in the Maldives and in the Brazil.
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.
Araneus angulatus is a species of orb-weaving spiders found in the Palearctic realm. It resembles the European garden spider, Araneus diadematus, but has distinctive tubercles on its abdomen. The species was first described in Aranei Svecici in 1757, where it was the first species described, making Araneus angulatus the first scientific name of an animal that is still in use.
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.
Cyrtophora exanthematica are tent spiders common in tropical Asia and Australia. They are commonly known as double-tailed tent spiders because of the pair of blunt projections at the end of their abdomens. They are harmless to humans.
Argiope katherina is a species of orb-weaver spider found in the northern parts of the Northern Territory and Western Australia. It was first described by Levi in 1983 and was named for Katherine Gorge. Specimens had been found at the mouth of split rock crevices up to one hundred metres from the Katherine River in sparse Pandanus-dominated territory.
Larinia jeskovi is a species of the family of orb weaver spiders and a part of the genus Larinia. It is distributed throughout the Americas, Africa, Australia, Europe, and Asia and commonly found in wet climes such as marshes, bogs, and rainforests. Larinia jeskovi have yellow bodies with stripes and range from 5.13 to 8.70 millimeters in body length. They build their webs on plants with a small height above small bodies of waters or wetlands. After sunset and before sunrise are the typical times they hunt and build their web. Males usually occupy a female's web instead of making their own. The mating behavior is noteworthy as male spiders often mutilate external female genitalia to reduce sperm competition while female spiders resort to sexual cannibalism to counter such mechanisms. The males also follow an elaborate courtship ritual to attract the female. The bite of Larinia jeskovi is not known to be of harm to humans.
