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Argiope (spider)
Encyclopedia
The genus
Argiope includes rather large and spectacular spider
s that have often a strikingly coloured abdomen
. These are well distributed throughout the world, and most countries in temperate or warmer climates have one or more species, which look similar.
In England, Argiope bruennichi, where it is found only on the southern coast, and in other parts of Europe, including Germany, is also known as the wasp spider. The East Asia
n species Argiope amoena is known in Japan
as kogane-gumo. In Australia
, Argiope keyserlingi and A. aetherea are known as St. Andrew's Cross spiders, for their habit of resting in the web
with legs outstretched in the shape of an X, the cross of St. Andrew. The large white zigzag in the centre of its web is called the stabilimentum
or web decoration.
In the Philippines
, it is known as gagambang ekis, which translates to X spider.
made by Argiope is pure white, and some species make an "X" form, or a zigzag type of web (often with a hollow centre). The spider then aligns one pair of its legs with each of the four lines in the hollow "X", making a complete "X" of white lines with a very eye-catching spider coloured bright yellow on a field of black or variegated red white and yellow stripes forming its centre. The white patterns are called stabilimentum and reflect UV light. They have been shown to play a role in attracting prey to the web, and possibly to prevent its destruction by large animals. The centres of their large webs are often just under 1 metre above the ground, so they are too low for anything much larger than a rabbit to walk under. The overtness of the spider and its web thus has been speculated to prevent larger creatures from accidentally destroying the web and possibly crushing the spider underfoot.
Other studies suggest that the stabilimenta may actually lead predators to the spider; species such as A. keyserlingi place their web predominantly in closed, complex habitats such as among sedges
.
As Argiope sit in the centre of their web during the day, they have developed several responses to predators, such as dropping off the web, retreating to the periphery of the web, or even rapidly pumping the web in bursts of up to 30 seconds, similar to the motion done by the unrelated Pholcus phalangioides
.
It is sometimes called sewing machine spider (because of the zigzag stitch in her web).
in the sac and emerge during the spring. The egg sac is composed of multiple layers of silk and protects its contents from damage; however, many species of insect
s have been observed to parasitise the egg sacs.
s, and they are capable of consuming prey up to twice their size. A. savigny was even reported to occasionally feed on the small bat
Rhynchonycteris naso. They might bite if grabbed, but other than for defense they do not attack large animals. Their venom
is not regarded as a serious medical problem for humans; indeed, they often contain a library of polyamine toxins with potential as therapeutic medicinal agents. Notable among these is the Argiotoxin
ArgTX-636 (A. lobata).
Genus
In biology, a genus is a low-level taxonomic rank used in the biological classification of living and fossil organisms, which is an example of definition by genus and differentia...
Argiope includes rather large and spectacular spider
Spider
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...
s that have often a strikingly coloured abdomen
Abdomen
In vertebrates such as mammals the abdomen constitutes the part of the body between the thorax and pelvis. The region enclosed by the abdomen is termed the abdominal cavity...
. These are well distributed throughout the world, and most countries in temperate or warmer climates have one or more species, which look similar.
Common Names
In North America, Argiope aurantia is commonly known as the black and yellow garden spider, corn spider, and writing spider, because of the similarity of the web stabilimenta to writing.In England, Argiope bruennichi, where it is found only on the southern coast, and in other parts of Europe, including Germany, is also known as the wasp spider. The East Asia
East Asia
East Asia or Eastern Asia is a subregion of Asia that can be defined in either geographical or cultural terms...
n species Argiope amoena is known in Japan
Japan
Japan is an island nation in East Asia. Located in the Pacific Ocean, it lies to the east of the Sea of Japan, China, North Korea, South Korea and Russia, stretching from the Sea of Okhotsk in the north to the East China Sea and Taiwan in the south...
as kogane-gumo. In Australia
Australia
Australia , officially the Commonwealth of Australia, is a country in the Southern Hemisphere comprising the mainland of the Australian continent, the island of Tasmania, and numerous smaller islands in the Indian and Pacific Oceans. It is the world's sixth-largest country by total area...
, Argiope keyserlingi and A. aetherea are known as St. Andrew's Cross spiders, for their habit of resting in the web
Spider web
A spider web, spiderweb, spider's web or cobweb is a device built by a spider out of proteinaceous spider silk extruded from its spinnerets....
with legs outstretched in the shape of an X, the cross of St. Andrew. The large white zigzag in the centre of its web is called the stabilimentum
Web decorations
A web decoration or stabilimentum is a conspicuous silk structure included in the webs of some species of orb-web spider...
or web decoration.
In the Philippines
Philippines
The Philippines , officially known as the Republic of the Philippines , is a country in Southeast Asia in the western Pacific Ocean. To its north across the Luzon Strait lies Taiwan. West across the South China Sea sits Vietnam...
, it is known as gagambang ekis, which translates to X spider.
Web
The average orb web is practically invisible, and it is easy to blunder into one and end up covered with a sticky web. The very easily visible pattern of banded silkSpider silk
Spider silk is a protein fiber spun by spiders. Spiders use their silk to make webs or other structures, which function as nets to catch other animals, or as nests or cocoons for protection for their offspring...
made by Argiope is pure white, and some species make an "X" form, or a zigzag type of web (often with a hollow centre). The spider then aligns one pair of its legs with each of the four lines in the hollow "X", making a complete "X" of white lines with a very eye-catching spider coloured bright yellow on a field of black or variegated red white and yellow stripes forming its centre. The white patterns are called stabilimentum and reflect UV light. They have been shown to play a role in attracting prey to the web, and possibly to prevent its destruction by large animals. The centres of their large webs are often just under 1 metre above the ground, so they are too low for anything much larger than a rabbit to walk under. The overtness of the spider and its web thus has been speculated to prevent larger creatures from accidentally destroying the web and possibly crushing the spider underfoot.
Other studies suggest that the stabilimenta may actually lead predators to the spider; species such as A. keyserlingi place their web predominantly in closed, complex habitats such as among sedges
Cyperaceae
Cyperaceae are a family of monocotyledonous graminoid flowering plants known as sedges, which superficially resemble grasses or rushes. The family is large, with some 5,500 species described in about 109 genera. These species are widely distributed, with the centers of diversity for the group...
.
As Argiope sit in the centre of their web during the day, they have developed several responses to predators, such as dropping off the web, retreating to the periphery of the web, or even rapidly pumping the web in bursts of up to 30 seconds, similar to the motion done by the unrelated Pholcus phalangioides
Pholcus phalangioides
The cellar spider or daddy longlegs , also known as the skull spider due to its cephalothorax looking like a human skull, is a spider of the family Pholcidae. Females have a body length of about 9 mm; males are slightly smaller. Its legs are about 5 or 6 times the length of its body...
.
It is sometimes called sewing machine spider (because of the zigzag stitch in her web).
Reproduction
The male spider is much smaller than the female, and unassumingly marked. When it is time to mate, he spins a companion web alongside the female's. After mating, the female lays her eggs, placing her egg sac into the web. The sac contains between 400 and 1400 eggs. These eggs hatch in autumn, but the spiderlings overwinterOverwinter
To overwinter is to pass through or wait out the winter season, or to pass through that period of the year when “winter” conditions make normal activity or even survival difficult or near impossible...
in the sac and emerge during the spring. The egg sac is composed of multiple layers of silk and protects its contents from damage; however, many species of insect
Insect
Insects are a class of living creatures within the arthropods that have a chitinous exoskeleton, a three-part body , three pairs of jointed legs, compound eyes, and two antennae...
s have been observed to parasitise the egg sacs.
Bite
Like almost all other spiders, Argiope are harmless to humans. Like most garden spiders they eat insectInsect
Insects are a class of living creatures within the arthropods that have a chitinous exoskeleton, a three-part body , three pairs of jointed legs, compound eyes, and two antennae...
s, and they are capable of consuming prey up to twice their size. A. savigny was even reported to occasionally feed on the small bat
Bat
Bats are mammals of the order Chiroptera "hand" and pteron "wing") whose forelimbs form webbed wings, making them the only mammals naturally capable of true and sustained flight. By contrast, other mammals said to fly, such as flying squirrels, gliding possums, and colugos, glide rather than fly,...
Rhynchonycteris naso. They might bite if grabbed, but other than for defense they do not attack large animals. Their venom
Venom
Venom is the general term referring to any variety of toxins used by certain types of animals that inject it into their victims by the means of a bite or a sting...
is not regarded as a serious medical problem for humans; indeed, they often contain a library of polyamine toxins with potential as therapeutic medicinal agents. Notable among these is the Argiotoxin
Argiotoxin
Argiotoxins represent a class of polyamine toxins isolated from the orb-weaver spider ....
ArgTX-636 (A. lobata).
External links
- Pictures of Argiope species (free for noncommercial use)
- Video of an Argiope spider in Sulawesi