Cyrtophora exanthematica

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Double-tailed tent spider
Cyrtophora.exanthematica.female.2.-.tanikawa.jpg
Female Cyrtophora exanthematica
Scientific classification OOjs UI icon edit-ltr.svg
Domain: Eukaryota
Kingdom: Animalia
Phylum: Arthropoda
Subphylum: Chelicerata
Class: Arachnida
Order: Araneae
Infraorder: Araneomorphae
Family: Araneidae
Genus: Cyrtophora
Species:
C. exanthematica
Binomial name
Cyrtophora exanthematica
(Doleschall, 1859)
Cyrtophora exanthematica distribution map.png
C. exanthematica distribution map [1]
Synonyms [1] [2]
  • Araneus exanthematica
    Pocock, 1900
  • Cyclosa bifurcata
    Paik, 1942
  • Cyrtophora exanthematica
    Lee, 1966
  • Epeira exanthematica
    Doleschall, 1859 [3]

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.

Contents

Double-tailed tent spiders build large nonsticky webs of two parts – a tangle web and a finely-meshed horizontal orb web. The females of the species are larger than the males and they may vary considerably in colour. They are easily distinguishable by their shape, the markings on their backs, and the way the females have the habit of guarding their eggs by splaying their bodies over them.

Description

Their common name 'double-tailed tent spider' comes from the pair of blunt projections at the posterior end of their abdomens. [4] They are also known under other common names in Australia, including dome spider, bowl spider, pan-web spider, and scoop-web spider. [4] [5] [6]

Double-tailed tent spiders from Okinawa, Japan
Cyrtophora.exanthematica.female.1.-.tanikawa.jpg
Adult female
Cyrtophora.exanthematica.male.-.tanikawa.jpg
Adult male

Like other members of the genus Cyrtophora, the upper side of the cephalothorax of double-tailed tent spiders are flattened. The cephalothorax, the sides of the abdomen, and the legs are covered with white hairs. Its leg formula is I,II,III,IV – that is, the longest legs are the first pair at the front, the second pair the next longest, the third pair shorter than the second, and the last pair the shortest. The eight eyes are more or less of equal size and arranged in two recurved rows. [1]

They also possess the characteristic pair of humps on the front side of their abdomen, somewhat resembling 'shoulders' and giving them the distinctive triangular shape. On the upper side are eight prominent sigilla (small pit-like depressions) arranged in two rows. The abdomen is subrectangular, with somewhat flat sides, and has small tubercules at the front. It is longer than it is wide and tapers down towards the rear. The bottom side of the abdomen is usually brown with yellow book lungs. The spinnerets are rimmed with white. The epigynum in females possesses a short triangular scape (or ovipositor). The sperm receptacles (spermathecae) are globular. [1]

They can vary considerably in colour. [7] They can be red, pink, orange, yellow, brown, grey, pale brown, or completely black. In some individuals two somewhat wavy and sometimes 'beaded' chalk-white line patterns are clearly visible, running from the front of the abdomen, to the tip of the 'humps', and down to below its pair of 'tails'. In others, they are only present as faint lines. [8]

Double-tailed tent spiders are sexually dimorphic, with the males generally far smaller than the females. [1] Female adults average around 10 mm (0.39 in) in length (excluding the legs), but can reach up to 15 mm (0.59 in). [6] Male adults average only 3.5 to 6 mm (0.14 to 0.24 in), with the abdomen about the same size as the cephalothorax and with prominent pedipalps. [4] [9]

Double-tailed tent spiders closely resemble Cyrtophora parangexanthematica in the Philippines. A fact reflected by its scientific name which literally means "like exanthematica" in Filipino. [1]

Taxonomy

Double-tailed tent spiders were first described by the Slovakian military surgeon Carl Ludwig Doleschall while stationed in Java in 1859 with the Dutch army. [10] He originally classified it under the genus Epeira (which is now the genus Araneus ). [1] They are currently classified under the genus Cyrtophora (tent-web spiders) under subfamily Cyrtophorinae. [11] They belong to the very large orb-weaver spider family (Araneidae). [12]

The generic name Cyrtophora means "curve bearer", from Greek κυρτός ("kurtós", meaning 'bent' or 'curved') and φόρος ("phoros", meaning 'bearer' or 'carrying'), referring to the shape of the abdomen of the members of the genus. [6] The specific name "exanthematica" comes from the Greek ἐξάνθημα ("exanthema", meaning 'pimple') and the suffix -ικος ("-ikos", meaning 'pertaining to'), a reference to its appearance. [13]

Ecology

Female Cyrtophora exanthematica guarding her egg sac Cyrtophora.exanthematica.female.with.eggsac.-.tanikawa.jpg
Female Cyrtophora exanthematica guarding her egg sac

Double-tailed tent spiders usually build their webs in branches of trees or shrubs, using surrounding leaves and twigs as a framework. The webs are composed of two distinct parts. The upper section is an irregular dense mass of random supporting webs (known as a 'tangle web'). It serves to discourage prey from entering from the top of the web complex. [5] At the bottom is a horizontally-oriented, exceptionally finely-meshed web (the 'orb web') about 0.5 m (1.6 ft) in diameter. [14] Like those of other tent-web spiders, this web is somewhat tent-like. Unlike the others, however, the orb webs of double-tailed tent spiders are often shaped more like a pan or a bowl. No part of the web is sticky, unlike the webs of other orb-weavers. [1]

The web of Cyrtophora exanthematica Cyrtophora.exanthematica.web.-.tanikawa.jpg
The web of Cyrtophora exanthematica

The spider stays in the middle of the lower orb web hanging upside down. [5] When it feels threatened, however, it will run to the edge of the web and hide among the vegetation and debris. [11] The spider has a sanctuary at the edge of the web surrounded by dead leaves which it can use to camouflage itself. [5] The male of the species can also inhabit the same web as the female. [11]

The webs are permanent. Over time, they will begin gathering leaves and other debris. Double-tailed tent spiders will regularly clean their webs, usually at night, though they will retain some bits and pieces of debris for camouflage. The webs sometimes have to be rebuilt when severely damaged. [11]

Double-tailed web spiders mate during summer. After mating, the female will lay her eggs in an egg sac (an ovoid ball of spider silk) in her sanctuary. She then stretches her body over the surface of the egg sac and guards it. This behavior is distinctive and makes the species easy to recognise. [9] The mother does not feed nor leave the sanctuary until the eggs have hatched, which is usually after two or three weeks. Only then will she return to the center of the web and resume her normal activities. The spiderlings will remain in her sanctuary for a few more weeks before setting out on their own. [5]

Because of the relatively large size of web, they are often infested with kleptoparasitic split-faced silver spiders ( Argyrodes fissifrons ). [14] While able to build webs of their own, dewdrop spiders (genus Argyrodes ) prefer to live and even reproduce in the webs of other spiders, stealing prey in the process. They can be permanently associated with one web or move around between several other tent webs in the immediate vicinity. The size of the web is directly proportional to the number of A. fissifrons inhabiting them. The relationships can sometimes be commensal or even mutual, as A. fissifrons eat prey entangled in the webs that are too small for the larger double-tailed tent spiders. However, they often help themselves to food stores or even food in the process of being consumed by the hosts as well. [15] Larger individuals are more audacious, but they usually stay on the tangle webs and out of the way of their hosts. Double-tailed tent spiders seem to tolerate their presence though they sometimes have to shove them away when they catch larger prey. [16]

Distribution and habitat

Double-tailed tent spiders are widespread in tropical Asia and Australia. Their native range extends from Australia to southern Japan and from the Philippines and Papua New Guinea to as far west as India. [14] They usually build their permanent webs on the branches of trees or shrubs. [4] [9]

Relations with humans

Like other tent-web spiders, double-tailed tent spiders are very shy. When threatened they will usually run away or play dead (also known as thanatosis). They are not aggressive to humans and they are unlikely to bite humans unless severely provoked. No bites have been recorded. [9]

The silk of double-tailed tent spiders are also among those being studied for possible applications in creating nanocapsules and microcapsules. [17]

See also

Related Research Articles

<i>Argiope</i> (spider) Genus of spiders

The genus Argiope includes rather large spiders that often have a strikingly coloured abdomen. These spiders are distributed throughout the world. Most countries in tropical or temperate climates host one or more species that are similar in appearance. The etymology of Argiope is from a Latin word argentum meaning silver. The carapace of Argiope species is typically covered in silvery hairs, and when crawling in the sun, they reflect it in a way that gives them a metallic, white appearance.

<i>Austracantha</i> Genus of spiders

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.

<i>Nephila</i> Genus of spiders

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.

<span class="mw-page-title-main">Bolas spider</span> Group of spiders that capture prey with a bolas

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.

<i>Cyrtophora</i> Genus of spiders

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.

<i>Nephila pilipes</i> Species of spider

Nephila pilipes is a species of golden orb-web spider. It resides all over countries in East and Southeast Asia as well as Oceania. It is commonly found in primary and secondary forests and gardens. Females are large and grow to a body size of 30–50 mm, with males growing to 5–6 mm. It is the second largest of the orb-weaving spiders apart from the recently discovered Nephila komaci. The first, second, and fourth pairs of legs of juvenile females have dense hairy brushes, but these brushes disappear as the spider matures.

<i>Argiope protensa</i> Species of spider

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.

<i>Metepeira labyrinthea</i> Species of spider

Metepeira labyrinthea, the labyrinth orbweaver, is a spider, with thin legs and a round, bulbous abdomen It is a member of the genus Metepeira in the family Araneidae. The female’s length is 5.3 mm, its carapace 2.3 mm, abdomen 3.3 mm, and extended legs 18.4 mm. The carapace is brown or gray, and the abdomen is dark with a white pattern. The legs alternate pale brown and dark brown, and the sternum is dark brown with a longitudinal yellow mark. The male spider is three-quarters of the female’s length, or slightly larger, with a darker carapace and with greater contrast between dark and light areas of the legs. Metepeira are easily distinguished from other Araneidae by their light eye region, white median line on the sternum, relative length of the leg segments, small male palpus, weakly sclerotized epigyne and the special composite web.

<i>Cyrtophora citricola</i> Species of spider

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.

<i>Argiope catenulata</i> Species of spider

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.

<i>Argiope pulchella</i> Species of arachnid

Argiope pulchella is a species of the orb-weaver spider family, Araneidae. It ranges from India to China and can be found on Java. It is a synanthropic species, often living in habitats associated with humans.

<span class="mw-page-title-main">Spider</span> Order of arachnids

Spiders are air-breathing arthropods that have eight limbs, 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 diversity among all orders of organisms. Spiders are found worldwide on every continent except for Antarctica, and have become established in nearly every land habitat. As of November 2023, 51,673 spider species in 136 families have been recorded by taxonomists. However, there has been debate among scientists about how families should be classified, with over 20 different classifications proposed since 1900.

<span class="mw-page-title-main">Cyrtophorinae</span> Subfamily of spiders

Cyrtophorinae is a subfamily of spiders in the orb-weaver spider family. Unlike other orb-weavers, spiders belonging to Cyrtophorinae build horizontal, finely meshed platforms within a tangle of irregular webs. The usually dome-shaped platform is a non-sticky orb web.

<i>Cyrtophora parangexanthematica</i> Species of spider

Cyrtophora parangexanthematica is a species of tent spider found in the Philippines. Its scientific name comes from its close resemblance to double-tailed tent spiders. It was described from a single female specimen collected in 1995.

<i>Araneus mitificus</i> Species of spider

Araneus mitificus, commonly known as the kidney garden spider or pale orb weaver is a species of orb-weaver spider found in South, East, and Southeast Asia.

<i>Cyrtophora moluccensis</i> Species of spider

Cyrtophora moluccensis is a tent-web spider in the orb-weaver family. It is commonly known as the tent spider or dome-web spider, and is native to India, Japan, Indonesia, Papua New Guinea, Australia, Fiji, and Tonga. It is often found in disturbed or open habitats from coasts to forest and mountainous interiors.

<i>Cyrtophora unicolor</i> Species of spider

Cyrtophora unicolor is a species of spider of the family Araneidae. It is known as the red tent spider.

<i>Allocyclosa</i> Genus of spiders

Allocyclosa is a genus of orb weaver spiders that contains only one species, Allocyclosa bifurca. It was first described in 1887 by McCook under the name Cyrtophora bifurca, and was transferred to its own genus in 1999. It is the only Cyclosa species north of Mexico to have a forked tail, hence the name bifurca, Latin for "two-forked". The forked abdomen, bearing two humps shaped like the letter M, is a defining feature in both males and females, though it is similar to features present in certain Cyrtophora species. Both sexes are a transparent green color, though only females have an area of red on their underside between the epigynum and the spinnerets. Females are nearly thirty percent larger than males, ranging from five to nine millimeters, while males range from two to three millimeters. Males are very uncommon. In a 1977 study by Levi, only two of the nearly 350 specimens that were positively identified as Cyrtophora bifurca were males. This is a very odd distribution, and it has been posed that females of the species, which have less prominent genitalia relative to other members of the orb-weaver family, may be parthenogenic, or able to reproduce without the help of males. Like other members of Araneidae, these spiders create orb webs, six to eight inches in diameter, but apply a unique form of protective mimicry. Females sit in the middle of a vertical row of web decoration, with egg sacs above and wrapped prey below. Because they all have a similar color and shape, it is difficult to discern between the egg sacs, the wrapped prey, and the spider itself.

<i>Argiope versicolor</i> Species of spider

Argiope versicolor, the multi-coloured Saint Andrew's cross spider, is a species of orb-weaver spider found mostly in Southeast Asia, from China to Indonesia.

Exechocentrus lancearius is a species of spider in the orb-weaver spider family Araneidae, found only in Madagascar. It was initially described from a partial specimen of an adult female. The first description of a complete specimen and its prey-catching behaviour was published in 2012. E. lancearius is a bolas spider. Rather than using a web, adult females catch their prey by using a line with one or two sticky drops which they swing.

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  17. Thomas Schelbel, Daniel Huemmerich, Andreas Bausch, & Kevin Hermanson (2010). Methods of Producing Nano- and Microcapsules of Spider Silk Proteins. U.S. Patent 11/989,907, filed August 1, 2006 and issued March 4, 2010.