St Andrew's cross spider | |
---|---|
![]() | |
Juvenile female Argiope keyserlingi from Brisbane | |
Scientific classification ![]() | |
Domain: | Eukaryota |
Kingdom: | Animalia |
Phylum: | Arthropoda |
Subphylum: | Chelicerata |
Class: | Arachnida |
Order: | Araneae |
Infraorder: | Araneomorphae |
Family: | Araneidae |
Genus: | Argiope |
Species: | A. keyserlingi |
Binomial name | |
Argiope keyserlingi Karsch, 1878 | |
Argiope keyserlingi is a species of orb-web spider found on the east coast of Australia, from Victoria to northern Queensland. [1] 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.
A. keyserlingi is commonly known as the St. Andrew's cross spider, due to the construction of bands of silk forming the arms of an X-shaped cross, similar to the one upon which St. Andrew is traditionally said to have been crucified. Juveniles of this species sometimes build a spiral-shaped pattern of silk. [2] Referred to as web decorations or stabilimenta, these bands are thought to increase the species' prey capture rate, but as in other species, they have been found to protect the spider against predators.
A. keyserlingi is an important model species in studies of spider ecology and behaviour. Using this species, scientists have investigated sperm competition, sexual size dimorphism, cryptic female choice, the role of pheromones in mating behaviour, and the function and evolution of web decorations.
Its main predators in Sydney are mantids and birds. [3]
This type of orb-weaver is cathemeral. [4]
The spider was named by Fredrich Karsch in 1878 after the mythological Greek character of Argiope, a nymph from the town Eleusis in southern Greece. [5] The specific name keyserlingi was chosen to honor arachnologist Eugen von Keyserling. [6]
Females of the species vary from 10 to 16 mm in size. Their glossy carapaces consist of silver, yellow, red, and black bands on their upper segment with two horizontal yellow belts beneath. Males of the species generally vary from 3 to 4 mm in size. They are brown and pearly coloured. St. Andrew's cross spiders rest with their legs oriented in pairs. [7]
The St Andrew's cross spider can be found mostly in rainforest margins, open forests, and heathlands of eastern Australia. They can also be found in the northern segment of the Northern Territory, in the northern segment of Tasmania, in the western segment of Western Australia, near Tedi River of Papua New Guinea, in the Malakula island of Vanuatu, in all areas of Lord Howe Island, in Bali Indonesia, and even near the Shihe-Shiguan River in China. They construct medium-sized webs on low, shrubby vegetation. [7]
Its web possesses meandering, bluish-white ribbons consisting of silk that can form either a full or partial cross through the center of the web. The purpose of the crucifix-like stabilimentum has long perplexed biologists, who first thought that the stabilimentum's purpose is to strengthen the web. Other ideas associate it with capturing prey or evading its predators, though the purpose of its stabilimentum remains a mystery. One feature of the stabilimentum is that it effectively reflects ultraviolet light, making it attractive to flying insects. Biologists think this may be to increase the chance of catching its prey. The design of the stabilimentum makes the web and the spider obvious to diurnal predators, especially birds and wasps. The shape of this decoration can vary from three shapes, a complete cross, a partial cross possessing one to three arms, or occasionally an absence of a decoration. This variability can induce web-recognition problems for predators. Biologists also found a possibility that the stabilimentum may be a warning to predators to stay away. [7]
Prey of the St Andrew's cross spider include flies, moths, butterflies, bees, and other insects. The orb-weaver wraps its prey immaculately with silk before digesting, and smaller prey may be prioritized. [7]
When the orb-weaver is threatened, it responds by either ejecting from its web or vibrating the web strenuously so the web becomes a blur, confusing its predator. These two methods may not always succeed, though, as sometimes their corpses can be found in mud cells of wasps and their webs can be left empty and damaged. [7]
Mating takes place from summer to autumn and is a perilous occasion for miniature male St Andrew's cross spiders. Males settle on the upper segment of the web; some of them may be missing legs, caused by encountering inhospitable females. The male then materializes a mating thread within the web, which he uses to attract the hospitable female by oscillating the thread. The female then hangs her pear-shaped sac in a mesh of threads, frequently surrounded by leaves to camouflage the sac's greenish silk, because egg sacs are the target of wasps and flies. [7]
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.
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.
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.
Argiope aetherea is a common, large orb-web spider. Like other species of Argiope, it is commonly known as the St Andrew's Cross spider, due to the characteristic cross-shaped web decorations female spiders often include in their webs. A. aetherea is similar in appearance to A. keyserlingi, however female A. aetherea are generally larger than A. keyserlingi. Like most orb-web spiders, A. aetherea shows considerable sexual size dimorphism, with females being many times larger than males.
Argiope picta is a species of orb web spider found in tropical areas of Queensland, Australia and Papua New Guinea up to the Moluccas. This species is similar in size to the sympatric Argiope aetherea; females can be distinguished from those of A. aetherea via extensive differences in abdominal colouration and patterns. The males of these two species are almost indistinguishable.
Argiope mascordi is a species of orb-web spider found in Queensland, Australia. The females of this species are smaller and less colourful than many other spiders in the genus Argiope. Males are larger than many other Argiope. Web decorations in this species are interesting in that A. mascordi juveniles construct a cross and adults construct a disc. The reason for this apparent reversal in decorating behaviour remains unknown.
Argiope bruennichi, commonly known as the wasp spider, is a species of orb-weaver spider found across Central and Northern Europe, several regions of Asia, plus parts of the Middle east, North Africa and the Azores. Like many other members of the same genus Argiope, this species features distinctive yellow, white and black markings on its abdomen.
Argiope aurantia is a species of spider, commonly known as the yellow garden spider, black and yellow garden spider, golden garden spider, writing spider, zigzag spider, zipper spider, black and yellow argiope, corn spider, Steeler spider, or McKinley spider. The species was first described by Hippolyte Lucas in 1833. It is common to the contiguous United States, Hawaii, southern Canada, Mexico, and Central America. It has distinctive yellow and black markings on the abdomen and a mostly white cephalothorax. Its scientific Latin name translates to "gilded silver-face". The body length of males range from 5–9 mm (0.20–0.35 in); females range from 19–28 mm (0.75–1.10 in). These spiders may bite if disturbed or harassed, but the venom is harmless to non-allergic humans, roughly equivalent to a bumblebee sting in intensity.
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.
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.
Argiope trifasciata is a species of spider native to North and South America, but now found around the world. It can be found in certain areas of Europe, namely the Iberian Peninsula, the Canary Islands, and Madeira. The similar looking Argiope bruennichi is common in the Azores. They typically begin to appear during autumn from early September to late October as temperatures start dropping. In Egypt, the type locality of this spider, females were found surviving the relatively warm winter months.
Argiope anasuja, is a species of harmless orb-weaver spider found from the Seychelles to India, Pakistan, Nepal, Sri Lanka, Maldives and in the Brazil.
Argiope pulchella is a species of the orb-weaver spider family, Araneidae. Its range extends from India to China, Indochina, and Sumatra. It is a synanthropic species, often living in habitats associated with humans.
Argiope aemula, commonly known as the oval St Andrew's cross spider, is a species of spider in the family Araneidae which is native to southeast Asia, found from India and Sri Lanka to the Philippines, Indonesia, and Vanuatu. It is one of the giant, conspicuous "signature spider" species of the genus Argiope, observed in tropical and subtropical grasslands.
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. 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 2mm 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.
Argiope magnifica is a species of orb web spider found in tropical areas of north-east Queensland, Australia, eastern Papua New Guinea and the Solomon Islands. It is commonly known as the magnificent St Andrew's cross spider. This species is similar in size to the sympatric Argiope keyserlingi; females can be distinguished from those of A. keyserlingi via extensive differences in abdominal colouration and patterns. The males of these two species are almost indistinguishable.
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.
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.
{{cite book}}
: CS1 maint: location (link)