''Tetragnatha extensa'' is a

species In biology, a species is the basic unit of classification and a taxonomic rank of an organism, as well as a unit of biodiversity. A species is often defined as the largest group of organisms in which any two individuals of the appropriate s ...

spider Spiders ( order Araneae) are air-breathing arthropods that have eight legs, chelicerae with fangs generally able to inject venom, and spinnerets that extrude silk. They are the largest order of arachnids and rank seventh in total species ...

found across the

Northern Hemisphere The Northern Hemisphere is the half of Earth that is north of the Equator. For other planets in the Solar System, north is defined as being in the same celestial hemisphere relative to the invariable plane of the solar system as Earth's Nort ...

. It has an elongate body, up to long, and adopts a straight line posture when alarmed. It lives on low vegetation in damp areas, and feeds on flying insects which it catches in its web.

Description

''T. extensa'' has an elongated, cream-coloured body. Males are smaller than females, at around body length, compared to for females. The four pairs of legs are very long, and are dark yellow. The carapace, which is around 1.8–2.6 mm long and 1.1–1.7 mm wide, is orange or dark yellow. The colouring of ''T. extensa'' is quite variable, ranging from creamy-yellow to green. On the underside, there is a thick black central band, with a silvery band on either side. ''T. extensa'' is distinguished from other members of the genus ''

Tetragnatha ''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. ...

'' by the minute curved tip of the male's conductor (part of the pedipalp), and the form of the female's

spermatheca The spermatheca (pronounced plural: spermathecae ), also called receptaculum seminis (plural: receptacula seminis), is an organ of the female reproductive tract in insects, e.g. ants, bees, some molluscs, oligochaeta worms and certain other ...

Distribution

''T. extensa'' has a wide distribution across the

(Holarctic). In

North America North America is a continent in the Northern Hemisphere and almost entirely within the Western Hemisphere. It is bordered to the north by the Arctic Ocean, to the east by the Atlantic Ocean, to the southeast by South America and the Car ...

, it is found from

Alaska Alaska ( ; russian: Аляска, Alyaska; ale, Alax̂sxax̂; ; ems, Alas'kaaq; Yup'ik: ''Alaskaq''; tli, Anáaski) is a state located in the Western United States on the northwest extremity of North America. A semi-exclave of the U.S., ...

Newfoundland Newfoundland and Labrador (; french: Terre-Neuve-et-Labrador; frequently abbreviated as NL) is the easternmost province of Canada, in the country's Atlantic region. The province comprises the island of Newfoundland and the continental region ...

, and its range extends south to

Washington Washington commonly refers to: * Washington (state), United States * Washington, D.C., the capital of the United States ** A metonym for the federal government of the United States ** Washington metropolitan area, the metropolitan area centered on ...

Colorado Colorado (, other variants) is a state in the Mountain West subregion of the Western United States. It encompasses most of the Southern Rocky Mountains, as well as the northeastern portion of the Colorado Plateau and the western edge of t ...

and

Pennsylvania Pennsylvania (; ( Pennsylvania Dutch: )), officially the Commonwealth of Pennsylvania, is a state spanning the Mid-Atlantic, Northeastern, Appalachian, and Great Lakes regions of the United States. It borders Delaware to its southeast, ...

. The species has a broad ecological range, having been found at the

tree line The tree line is the edge of the habitat at which trees are capable of growing. It is found at high elevations and high latitudes. Beyond the tree line, trees cannot tolerate the environmental conditions (usually cold temperatures, extreme snowp ...

in the

Rocky Mountains The Rocky Mountains, also known as the Rockies, are a major mountain range and the largest mountain system in North America. The Rocky Mountains stretch in straight-line distance from the northernmost part of western Canada, to New Mexico in ...

. It is found in coastal vegetation in

Europe Europe is a large peninsula conventionally considered a continent in its own right because of its great physical size and the weight of its history and traditions. Europe is also considered a Continent#Subcontinents, subcontinent of Eurasia ...

. ''T. extensa'' is found throughout the

United Kingdom The United Kingdom of Great Britain and Northern Ireland, commonly known as the United Kingdom (UK) or Britain, is a country in Europe, off the north-western coast of the continental mainland. It comprises England, Scotland, Wales and North ...

, where it is the commonest species of ''

'', and one of the commonest spiders. It is also found in Madeira.

Ecology and behaviour

''Tetragnatha extensa'' is found on low-growing vegetation, usually in damp areas. It feeds on

insect Insects (from Latin ') are pancrustacean hexapod invertebrates of the class Insecta. They are the largest group within the arthropod phylum. Insects have a chitinous exoskeleton, a three-part body ( head, thorax and abdomen), three pairs ...

s, including mosquitos,

midge A midge is any small fly, including species in several families of non-mosquito Nematoceran Diptera. Midges are found (seasonally or otherwise) on practically every land area outside permanently arid deserts and the frigid zones. Some mid ...

s and

moth Moths are a paraphyletic group of insects that includes all members of the order Lepidoptera that are not butterflies, with moths making up the vast majority of the order. There are thought to be approximately 160,000 species of moth, many of w ...

s, which it catches in its loosely constructed

web Web most often refers to: * Spider web, a silken structure created by the animal * World Wide Web or the Web, an Internet-based hypertext system Web, WEB, or the Web may also refer to: Computing * WEB, a literate programming system created by ...

. When alarmed, it will sit along a plant stem, a blade of

grass Poaceae () or Gramineae () is a large and nearly ubiquitous family of monocotyledonous flowering plants commonly known as grasses. It includes the cereal grasses, bamboos and the grasses of natural grassland and species cultivated in lawns an ...

or the central vein of a

leaf A leaf ( : leaves) is any of the principal appendages of a vascular plant stem, usually borne laterally aboveground and specialized for photosynthesis. Leaves are collectively called foliage, as in "autumn foliage", while the leaves, ste ...

, with its four front legs pointing forwards, and its four back legs pointing backwards for

camouflage Camouflage is the use of any combination of materials, coloration, or illumination for concealment, either by making animals or objects hard to see, or by disguising them as something else. Examples include the leopard's spotted coat, the ...

. ''T. extensa'' is able to walk on the surface of water, where it can move faster than on land.

Life cycle

Adults are seen between May and September in the United Kingdom, and between May and July in Alaska. There is little

courtship Courtship is the period wherein some couples get to know each other prior to a possible marriage. Courtship traditionally may begin after a betrothal and may conclude with the celebration of marriage. A courtship may be an informal and private m ...

, and the male and female lock jaws, possibly to prevent the female from eating the male before mating. The egg sacs are globular and covered with grey tufted

silk Silk is a natural protein fiber, some forms of which can be woven into textiles. The protein fiber of silk is composed mainly of fibroin and is produced by certain insect larvae to form cocoons. The best-known silk is obtained from the coc ...

, resembling a bird dropping, and are pressed against a plant stem.

Overwintering Overwintering is the process by which some organisms pass through or wait out the winter season, or pass through that period of the year when "winter" conditions (cold or sub-zero temperatures, ice, snow, limited food supplies) make normal activi ...

occurs in the form of early-

instar An instar (, from the Latin '' īnstar'', "form", "likeness") is a developmental stage of arthropods, such as insects, between each moult (''ecdysis''), until sexual maturity is reached. Arthropods must shed the exoskeleton in order to grow or ass ...

spiderlings.

Taxonomic history

''Tetragnatha extensa'' was first given a

binomial Binomial may refer to: In mathematics *Binomial (polynomial), a polynomial with two terms * Binomial coefficient, numbers appearing in the expansions of powers of binomials *Binomial QMF, a perfect-reconstruction orthogonal wavelet decomposition ...

Carl Linnaeus Carl Linnaeus (; 23 May 1707 – 10 January 1778), also known after his ennoblement in 1761 as Carl von Linné Blunt (2004), p. 171. (), was a Swedish botanist, zoologist, taxonomist, and physician who formalised binomial nomenclature, the ...

in his ''

Systema Naturae ' (originally in Latin written ' with the ligature æ) is one of the major works of the Swedish botanist, zoologist and physician Carl Linnaeus (1707–1778) and introduced the Linnaean taxonomy. Although the system, now known as binomial nomen ...

'' of 1758, the starting point of zoological nomenclature. In that work, it was included in the genus ''Aranea'' (now ''

Araneus ''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. Description Spiders of this genus prese ...

''). ''T. extensa'' is a very common, widespread and variable species, and a number of

synonyms A synonym is a word, morpheme, or phrase that means exactly or nearly the same as another word, morpheme, or phrase in a given language. For example, in the English language, the words ''begin'', ''start'', ''commence'', and ''initiate'' are all ...

have been published: *''Aranea extensa'' Linnaeus,

1758 Events January–March * January 1 – Swedish biologist Carl Linnaeus (Carl von Linné) publishes in Stockholm the first volume (''Animalia'') of the 10th edition of Systema Naturae, 10th edition of ''Systema Naturae'', the sta ...

*''Aranea solandri'' Scopoli, 1763 *''Aranea mouffeti'' Scopoli, 1763 *''Tetragnatha rubra'' Risso, 1826 *''Tetragnatha gibba'' C. L. Koch, 1837 *''Tetragnatha chrysochlora'' Walckenaer, 1841 *''Tetragnatha arundinis'' Bremi-Wolff, 1849 *''Tetragnatha fluviatilis'' Keyserling, 1865 *''Tetragnatha nowickii'' L. Koch, 1870 *''Tetragnatha groenlandica'' Thorell, 1872 *''Tetragnatha solandri'' (Scopoli, 1763) *''Tetragnatha manitoba'' Chamberlin & Ivie, 1942 *''Tetragnatha rusticana'' Chickering, 1959 *''Tetragnatha potanini'' Schenkel, 1963 *''Tetragnatha maderiana'' Wunderlich, 1987

References

External links

* {{Taxonbar, from=Q1500718 Tetragnathidae Holarctic spiders Spiders of Europe Arthropods of Madeira Spiders of Russia Spiders of Asia Fauna of Iran Spiders of North America Fauna of Alaska Spiders described in 1758 Taxa named by Carl Linnaeus