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''Nephila'' is a
genus Genus ( plural genera ) is a taxonomic rank used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, viruses. In the hierarchy of biological classification, genus com ...
of
araneomorph The Araneomorphae (also called the Labidognatha) are an infraorder of spiders. They are distinguishable by chelicerae (fangs) that point diagonally forward and cross in a pinching action, in contrast to the Mygalomorphae (tarantulas and their cl ...
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 ...
s noted for the impressive webs they weave. ''Nephila'' consists of numerous species found in warmer regions around the world. They are commonly called golden silk orb-weavers, golden orb-weavers, giant wood spiders, or banana spiders.


Etymology

The genus name ''Nephila'' is derived from
Ancient Greek Ancient Greek includes the forms of the Greek language used in ancient Greece and the ancient world from around 1500 BC to 300 BC. It is often roughly divided into the following periods: Mycenaean Greek (), Dark Ages (), the Archaic peri ...
, meaning "fond of spinning", from the words νεῖν (''nein'') = to spin (related to ''nema'' νήμα "thread") + φίλος (''philos'') = "love".


Description

''Nephila'' spiders vary from reddish to greenish yellow in color with distinctive whiteness on the
cephalothorax The cephalothorax, also called prosoma in some groups, is a tagma of various arthropods, comprising the head and the thorax fused together, as distinct from the abdomen behind. (The terms ''prosoma'' and ''opisthosoma'' are equivalent to ''cepha ...
and the beginning of the abdomen. Like many species of the superfamily
Araneoidea Araneoidea is a taxon of araneomorph spiders, termed "araneoids", treated as a superfamily. As with many such groups, its circumscription has varied; in particular some families that had at one time moved to the Palpimanoidea have more recently ...
, most of them have striped legs specialized for weaving (where their tips point inward, rather than outward as is the case with many wandering spiders). Their contrast of dark brown/black and green/yellow allows warning and repelling of potential predators to which their venom might be of little danger. Golden orb-weavers reach sizes of 4.8–5.1 cm (1.5–2 in) in females, not including legspan, with males being usually two-thirds smaller (less than 2.5 cm, 1 in). In 2012, a large individual was photographed killing and consuming a 0.5-m-long
brown tree snake The brown tree snake (''Boiga irregularis''), also known as the brown catsnake, is an arboreal rear-fanged colubrid snake native to eastern and northern coastal Australia, eastern Indonesia (Sulawesi to Papua), Papua New Guinea, and many islands ...
in
Freshwater, Queensland Freshwater is a suburb of Cairns in the Cairns Region, Queensland, Australia. In the , Freshwater had a population of 2,023 people. The suburb was once a separate town in the Shire of Mulgrave but was amalgamated into the City of Cairns, wh ...
. Species from Taiwan have been known to reach over , legspan included, in mountainous country. In 2014, a study discovered that golden orb-weavers living in urban areas, particularly areas of a high socioeconomic status, grew larger and carried more eggs than those in their native habitats. A number of possible explanations were suggested, such as increased food supplies due to artificial light or lack of
predator Predation is a biological interaction where one organism, the predator, kills and eats another organism, its prey. It is one of a family of common feeding behaviours that includes parasitism and micropredation (which usually do not kill th ...
s and
parasite Parasitism is a close relationship between species, where one organism, the parasite, lives on or inside another organism, the host, causing it some harm, and is adapted structurally to this way of life. The entomologist E. O. Wilson has ...
s.


Species

In 2018, twelve ''Nephila'' species were reclassified as ''Trichonephila'', with another two (''N. kuhlii'' and ''N. robusta'') considered in 2020 to be junior synonyms of ''N. pilipes''. Species whose placement has been changed by some sources include: *''Nephila laurinae'' was considered to be a synonym of '' Trichonephila antipodiana'' ("Batik Golden Web Spider"), found most commonly in the Philippines and Vietnam *'' Trichonephila komaci'', found most commonly in South Africa and Madagascar, transferred from ''Nephila komaci'' *''
Trichonephila clavipes ''Trichonephila clavipes'' (formerly known as ''Nephila clavipes''), commonly known as the golden silk orb-weaver, golden silk spider, or banana spider (a name shared with several others), is an orb-weaving spider species which inhabits forests ...
'' (or "banana spider") found most commonly in Central America, transferred from ''Nephila clavipes'' *''
Trichonephila inaurata ''Trichonephila inaurata'', synonym ''Nephila inaurata'', commonly known as the red-legged golden orb-weaver spider or red-legged nephila, is a species of orb-weaver spider of the genus '' Trichonephila''. It is native to southern and East Af ...
'' (or "red-legged golden orb-weaver spider") found most commonly in southern and East Africa, transferred from ''Nephila inaurata'' *''
Trichonephila plumipes ''Trichonephila plumipes'' is a species of spider found in Australia, Indonesia and some Pacific Islands, which exhibits extreme sexual dimorphism through its sexual cannibalism behavior. It is sometimes called the tiger spider due to its marking ...
'' (or "tiger spider") found most commonly in Australia, transferred from ''Nephila plumipes'' , the
World Spider Catalog The World Spider Catalog (WSC) is an online searchable database concerned with spider taxonomy. It aims to list all accepted families, genera and species, as well as provide access to the related taxonomic literature. The WSC began as a series of ...
did not accept all of these changes, listing the following species in the genus ''Nephila'': *''
Nephila comorana ''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. They are commonly called golden silk orb-weavers, golden orb-weavers, gian ...
'' Strand, 1916 – Comoros, Mayotte *''
Nephila constricta ''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. They are commonly called golden silk orb-weavers, golden orb-weavers, gian ...
'' Karsch, 1879 – Tropical Africa *''
Nephila cornuta ''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. They are commonly called golden silk orb-weavers, golden orb-weavers, gian ...
'' (Pallas, 1772) – Guyana *''
Nephila dirangensis ''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. They are commonly called golden silk orb-weavers, golden orb-weavers, gian ...
'' Biswas & Biswas, 2006 – India *''
Nephila kuhli ''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. They are commonly called golden silk orb-weavers, golden orb-weavers, gian ...
'' (Doleschall, 1859) – Myanmar to Indonesia *''
Nephila laurinae ''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. They are commonly called golden silk orb-weavers, golden orb-weavers, gian ...
'' Thorell, 1881 – Malaysia to Solomon Is. *''
Nephila pakistaniensis ''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. They are commonly called golden silk orb-weavers, golden orb-weavers, gian ...
'' Ghafoor & Beg, 2002 – Pakistan *''
Nephila pilipes ''Nephila pilipes'' (northern golden orb weaver or giant golden orb weaver''Nephila pilipes''
Ar ...
'' (Fabricius, 1793) ( type) – India to China,
Vietnam Vietnam or Viet Nam ( vi, Việt Nam, ), officially the Socialist Republic of Vietnam,., group="n" is a country in Southeast Asia, at the eastern edge of mainland Southeast Asia, with an area of and population of 96 million, making i ...
,
Philippines The Philippines (; fil, Pilipinas, links=no), officially the Republic of the Philippines ( fil, Republika ng Pilipinas, links=no), * bik, Republika kan Filipinas * ceb, Republika sa Pilipinas * cbk, República de Filipinas * hil, Republ ...
,
Taiwan Taiwan, officially the Republic of China (ROC), is a country in East Asia, at the junction of the East and South China Seas in the northwestern Pacific Ocean, with the People's Republic of China (PRC) to the northwest, Japan to the nort ...
,
Australia Australia, officially the Commonwealth of Australia, is a Sovereign state, sovereign country comprising the mainland of the Australia (continent), Australian continent, the island of Tasmania, and numerous List of islands of Australia, sma ...
*'' Nephila tetragnathoides'' (Walckenaer, 1841) – Fiji, Tonga, Niue *'' Nephila vitiana'' (Walckenaer, 1847) – Indonesia, Fiji, Tonga Additional fossil species are known from the
Cenozoic The Cenozoic ( ; ) is Earth's current geological era, representing the last 66million years of Earth's history. It is characterised by the dominance of mammals, birds and flowering plants, a cooling and drying climate, and the current configura ...
. In 2012 ''Geratonephila burmanica'' was described from the
Cenomanian The Cenomanian is, in the ICS' geological timescale, the oldest or earliest age of the Late Cretaceous Epoch or the lowest stage of the Upper Cretaceous Series. An age is a unit of geochronology; it is a unit of time; the stage is a unit in the s ...
aged
Burmese amber Burmese amber, also known as Burmite or Kachin amber, is amber from the Hukawng Valley in northern Myanmar. The amber is dated to around 100 million years ago, during the latest Albian to earliest Cenomanian ages of the mid-Cretaceous period. The ...
, Wunderlich 2015 synonymised ''Geratonephilia'' with ''Nephilia tenuis,'' a species from the
Dominican Amber Dominican amber is amber from the Dominican Republic derived from resin of the extinct tree '' Hymenaea protera''. Dominican amber differentiates itself from Baltic amber by being nearly always transparent, and it has a higher number of fossil inc ...
, as he considered it unlikely that the amber was actually Burmese in origin. Though largely ambiguous, the origins of ''Nephila'' are undoubtedly Gondowanan. With the prime candidates being
Africa Africa is the world's second-largest and second-most populous continent, after Asia in both cases. At about 30.3 million km2 (11.7 million square miles) including adjacent islands, it covers 6% of Earth's total surface area ...
,
Indomalaya The Indomalayan realm is one of the eight biogeographic realms. It extends across most of South and Southeast Asia and into the southern parts of East Asia. Also called the Oriental realm by biogeographers, Indomalaya spreads all over the Indi ...
, and
Australasia Australasia is a region that comprises Australia, New Zealand and some neighbouring islands in the Pacific Ocean. The term is used in a number of different contexts, including geopolitically, physiogeographically, philologically, and ecologica ...
. Black wood spider (Nephila kuhlii).jpg, ''N. kuhlii'' dorsal side Black wood spider (Nephila kuhlii) ventral.jpg, ''N. kuhlii'' ventral side


Distribution and habitat

Golden silk orb-weavers are widespread in warmer regions throughout the world, with species in
Australia Australia, officially the Commonwealth of Australia, is a Sovereign state, sovereign country comprising the mainland of the Australia (continent), Australian continent, the island of Tasmania, and numerous List of islands of Australia, sma ...
,
Asia Asia (, ) is one of the world's most notable geographical regions, which is either considered a continent in its own right or a subcontinent of Eurasia, which shares the continental landmass of Afro-Eurasia with Africa. Asia covers an area ...
,
Africa Africa is the world's second-largest and second-most populous continent, after Asia in both cases. At about 30.3 million km2 (11.7 million square miles) including adjacent islands, it covers 6% of Earth's total surface area ...
(including
Madagascar Madagascar (; mg, Madagasikara, ), officially the Republic of Madagascar ( mg, Repoblikan'i Madagasikara, links=no, ; french: République de Madagascar), is an island country in the Indian Ocean, approximately off the coast of East Africa ...
), and the
Americas The Americas, which are sometimes collectively called America, are a landmass comprising the totality of North and South America. The Americas make up most of the land in Earth's Western Hemisphere and comprise the New World. Along with th ...
. Spiderlings can be carried by the wind over long distances, and each year, a small number of female golden orb web spiders are found in New Zealand (where they are not endemic) after having been blown across the
Tasman Sea The Tasman Sea (Māori: ''Te Tai-o-Rēhua'', ) is a marginal sea of the South Pacific Ocean, situated between Australia and New Zealand. It measures about across and about from north to south. The sea was named after the Dutch explorer Abe ...
; the spiders usually end up in the
North Island The North Island, also officially named Te Ika-a-Māui, is one of the two main islands of New Zealand, separated from the larger but much less populous South Island by the Cook Strait. The island's area is , making it the world's 14th-largest ...
. Whilst the geographic distribution of ''Nephila'' is large, many habitat similarities are seen between these locations. A warm and reasonably wet climate is generally preferred, as these are some of the environmental cues that induce spiderling hatching.Higgins, L. (2017). ''Nephila'' Life Cycle. nlineUvm.edu. Available at: http://www.uvm.edu/~lehiggin/LifeCycle.html ccessed 30 May 2017 Locally, spiders look for relatively dense vegetation where webs can be set up in areas that insects will regularly fly through. Urban environments are also attractive due to the large prey concentrations and lower levels of predation.


Behavior


Web spinning and structure

''Nephila'' spiders produce large asymmetric orb webs up to in diameter. ''Nephila'' species remain in their webs permanently, so have a higher predation risk. The golden silk orb-weaver is named for the yellow color of the
spider silk Spider silk is a protein fibre spun by spiders. Spiders use their silk to make Spider web, webs or other structures, which function as sticky nets to catch other animals, or as nests or cocoons to protect their offspring, or to wrap up prey. ...
used to construct these webs. Yellow threads of their web shine like gold in sunlight.
Carotenoid Carotenoids (), also called tetraterpenoids, are yellow, orange, and red organic compound, organic pigments that are produced by plants and algae, as well as several bacteria, and Fungus, fungi. Carotenoids give the characteristic color to pumpki ...
s are the main contributors to this yellow color, but xanthurenic acid, two
quinone The quinones are a class of organic compounds that are formally "derived from aromatic compounds
uch as benzene or naphthalene Uch ( pa, ; ur, ), frequently referred to as Uch Sharīf ( pa, ; ur, ; ''"Noble Uch"''), is a historic city in the southern part of Pakistan's Punjab province. Uch may have been founded as Alexandria on the Indus, a town founded by Alexand ...
by conversion of an even number of –CH= groups into –C(=O)– groups with any necessary rearrangement of double ...
s, and an unknown compound may also aid in the color. Experimental evidence suggests that the silk's color may serve a dual purpose: sunlit webs ensnare bees that are attracted to the bright yellow strands, whereas in shady spots, the yellow blends in with background foliage to act as a camouflage. The spider is able to adjust pigment intensity relative to background light levels and color; the range of spectral reflectance is specifically adapted to insect vision. The webs of most ''Nephila'' spiders are complex, with a fine-meshed orb suspended in a maze of non-sticky barrier webs. As with many weavers of sticky spirals, the orb is renewed regularly if not daily, apparently because the stickiness of the orb declines with age. When weather is good (and no rain has damaged the orb web), subadults and adults often rebuild only a portion of the web. The spider removes and consumes the portion to be replaced, builds new radial elements, then spins the new spirals. This partial orb renewal is distinct from other orb-weaving spiders that usually replace the entire orb web. The web of ''
Nephila antipodiana ''Nephila antipodiana'', also known as the batik golden web spider, is a species of golden orb-web spider discovered in 1841 by Charles Athanase Walckenaer. The species is found throughout Australia, China, Indonesia, the Philippines, and Thai ...
'' contains ant-repellent chemicals to protect the web. Typically, the golden orb-weaver first weaves a nonsticky spiral with space for two to 20 more spirals in between (the density of sticky spiral strands decreases with increasing spider size). When she has completed the coarse weaving, she returns and fills in the gaps. Whereas most orb-weaving spiders remove the nonsticky spiral when spinning the sticky spiral, ''Nephila'' spiders leave it. This produces a "
manuscript paper Manuscript paper (sometimes staff paper in U.S. English, or just music paper) is paper preprinted with staves ready for musical notation. Manuscript paper is also available for drum notation and guitar tabulature.Sainsbury, Christopher. “Bi- ...
" effect when the orb is seen in the sun: groups of sticky spirals reflecting light with "gaps" where the nonsticky spiral does not reflect the light. In relation to the ground, the webs of adults may be woven from eye-level upwards high into the tree canopy. The orb web is usually truncated by a top horizontal support strand, giving it an incomplete look. Adjacent to one face of the main orb, a rather extensive and haphazard-looking network of guard-strands may be suspended a few centimeters distant across a free space. This network is often decorated with a lumpy string or two of plant detritus and insect carcasses clumped with silk. This "barrier web" may function as a kind of early-warning system for incoming prey or against spider-hunting predators, or as a shield against windblown leaves; it may also be remnants of the owner's previous web. At least one reference explains the suspended debris-chain as a cue for birds to avoid blundering into and destroying the web.


Prey capture and feeding

The golden silk orb-weaver targets many different organisms as prey, ranging from small flies and beetles to larger cicadas and locusts. As a result of their strong web structure, small birds and bats can also become trapped and fed upon. Whilst most of the captured prey is relatively small compared to ''Nephila'', the majority of biomass consumed comes from larger, rarer prey. Prey larger than 66% of the captor's size accounts for just 16.5% of prey captured, but 85% of prey consumed, indicating the spider is selective in its feeding habits. Spiders are notified that potential prey has been caught in the web through vibrations along strands, and these can be followed to the prey location on the web and be used to estimate prey size. ''Nephila'' species also create caches of food for storage, which can be found above the hub of the web and contain up to 15 prey items. These items are arranged in a line vertically and are wrapped in silk to reduce dehydration. Caches are created and grow when prey is readily available and more biomass is available for consumption than is required by the spider. The purpose of caches is to have a backup food source when prey is scarce and occasionally to provide bait to attract more prey to the web. ''Nephila'' species may also respond to food shortages by moving their webs, but this is a response to longer periods of prey scarcity than cache creation.Robinson, M. and Robinson, B. (1973). Ecology and behavior of the giant wood spider ''Nephila maculata'' (Fabricius) in New Guinea. Smithsonian Contributions to Zoology, (149), pp.1-76. Web moving is seen as a result of environmental change, whereas caches occur from environmental fluctuation.


Mating and reproduction

''Nephila'' spiders display large sexual dimorphism in size, with females being greatly larger than males. Debate exists as to whether this is a result of male dwarfism or female gigantism. Smaller males may be selected for due to the presence of competition for mating. Smaller males are quicker and more nimble, allowing them to be able to catch the females more easily, as well as to escape when threatened. Larger males may have to wait for the female to come close due to their slower speed. Larger females may have been selected for as a result of males using
mating plug A mating plug, also known as a copulation plug, sperm plug, vaginal plug, or sphragis (Latin, from Greek σφραγίς ''sphragis'', "a seal"), is gelatinous secretion used in the mating of some species. It is deposited by a male into a female ge ...
s upon copulation. Larger individuals reduce the success of these plugs, allowing for multiple mating and reducing the risk of genital mutilation. Gigantism in females is also associated with fecundity, as larger individuals can produce more eggs and therefore increase reproductive success. When males are fully mature, they leave their webs to search for a suitable female, often using web characteristics to identify potential mates. Often, multiple males attempt to court the same female, thus competition for territory on the web occurs, but is rarely physical, as smaller males surrender area to larger ones. When males approach females, they are often feeding, allowing the males to get closer without an aggressive response and also meaning the female is not moving. On approach, the male makes himself known by tapping on a web strand to ensure the female is amenable before proceeding to mate. When met with aggression, males stop approaching and remain in the same location until the female relaxes or they retreat. Females engage in multiple mating, but no benefit to the offspring occurs as a result of this; however, the energy cost of repelling a male is higher than that of allowing him to copulate. As a result of this, sperm competition occurs through males altering the duration and frequency of mating, with longer mating being proportional to a greater likelihood of success.
Sexual cannibalism Sexual cannibalism is when an animal, usually the female, cannibalizes its mate prior to, during, or after copulation.Polis, G.A. & Farley, R.D. Behavior and Ecology of Mating in the journal of Arachnology 33-46 (1979). It is a trait observed in m ...
is uncommon in ''Nephila'' as a result of male mating behaviours. By copulating when females are immobile after molting or inactive due to feeding, the males increase their chances of survival. Males also approach from the side of the web opposite the female, increasing the odds of a successful approach. Male ''
Nephila pilipes ''Nephila pilipes'' (northern golden orb weaver or giant golden orb weaver''Nephila pilipes''
Ar ...
'' is reported to have a mate binding behavior to avoid sexual cannibalism. Sexual cannibalism does still occur, but generally is more common with larger males, and from older females. Females produce an egg sac in the surrounding environs of the web to protect their eggs. The eggs are deposited on a silk platform, then are covered in loose silk to form a sac, which is firmly attached to surrounding vegetation so that it is hidden from the view of predators. It is reported that egg sacs are mostly under leaves and other coverings. However, only ''
Nephila pilipes ''Nephila pilipes'' (northern golden orb weaver or giant golden orb weaver''Nephila pilipes''
Ar ...
'' is different than other ''Nephila'' species. They lay eggs in small pits on the ground to avoid parasitism. These sacs can contain from 300 to 3000 eggs, depending on mating success and particular species. Once hatched, the spiderlings inhabit a communal web to begin their lives.


Thermoregulation

''Nephila'' spiders change their body positioning relative to the sun to maintain internal temperatures at an optimal level. As ambient temperatures increase, the spiders position themselves so the abdomen shades the cephalothorax from the sun. Spiders may also hang from their hind legs as a result of the heat due to a loss of hydrostatic pressure. Conversely, as temperatures cool down, the spiders position themselves perpendicular to the sun to retain as much heat energy as possible. When ambient temperatures reach extreme highs (above 40 °C), they may leave their webs and seek shade in the surrounding environment.


Predation and parasitism

Predation of ''Nephila'' species is relatively uncommon; when it does occur, the main group affected are the juvenile individuals. The major predators are birds, but wasps and damselflies also prey upon smaller juveniles. ''Nephila'' species are frequently parasitized by ''
Argyrodes ''Argyrodes'', also called dewdrop spiders, is a genus of comb-footed spiders that was first described by Eugène Louis Simon in 1864. They occur worldwide, and are best known for their kleptoparasitism. They can spin their own webs, but tend to ...
'', a genus of very small black-and-silver spiders that are
kleptoparasitic Kleptoparasitism (etymologically, parasitism by theft) is a form of feeding in which one animal deliberately takes food from another. The strategy is evolutionarily stable when stealing is less costly than direct feeding, which can mean when f ...
. As many as a few dozen may infest a single ''Nephila'' web to feed from the host spider's captured prey. The frequent rebuilding or abandoning of webs by ''Nephila'' may be a tactic for controlling ''Argyrodes''.
Spiny orb-weaver ''Gasteracantha'' is a genus of orb-weaver spiders first named by Carl Jakob Sundevall in 1833. Species of the genus are known as spiny-backed orb-weavers, spiny orb-weavers, or spiny spiders. The females of most species are brightly colored wi ...
spiders of the genus ''Gasteracantha'' also inhabit the webs of ''Nephila'' as kleptoparasites. Egg sacs generally remain free from both predation and parasitism, often due to the close proximity of the mother and how well it is hidden.


Life cycle


Spiderlings

''Nephila'' spiderlings leave the egg sac as a result of environmental cues, often warmer and wetter conditions in spring. They then live on a communal web, eating dead siblings and web debris for around a week before dispersing to make individual webs. Young spiders do not generally build yellow-colored silk, and the young themselves can be easily mistaken for young orchard spiders (''
Leucauge ''Leucauge'' () is a spider genus of long-jawed orb weavers, with over 160 species and fully pantropical distribution. The genus was first documented in Scottish zoologist Adam White's 1841 ''Description of new or little known Arachnida''. Cha ...
'') in general color and shape (both genera sport silver stripes or patches on their abdomens, described in some references as a form of heat control). The best distinction between ''Leucauge'' and ''Nephila'' juveniles is web structure: ''Leucauge'' species tend to build horizontal orbs that form a perfect circle, whereas ''Nephila'' species build vertical, elliptical orbs that are incomplete (missing the portion of the orb over the hub, the center where the spider sits). The latter seem to prefer more open habitat such as second-growth scrub or forest edges. Fences or building overhangs often do just as nicely.


Molting and growth

Once they are juvenile, ''Nephila'' spiders inhabit their individual webs, then begin their growth by the molting process. The time between molts is called an
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 ...
and seven to 12 of these can occur depending on food availability.
Ecdysis Ecdysis is the moulting of the cuticle in many invertebrates of the clade Ecdysozoa. Since the cuticle of these animals typically forms a largely inelastic exoskeleton, it is shed during growth and a new, larger covering is formed. The remna ...
, the shedding of the
exoskeleton An exoskeleton (from Greek ''éxō'' "outer" and ''skeletós'' "skeleton") is an external skeleton that supports and protects an animal's body, in contrast to an internal skeleton (endoskeleton) in for example, a human. In usage, some of the ...
, occurs through the formation of a soft exoskeleton inside the current one. Once the old exoskeleton is shed, the new, larger one begins to harden. Ecdysis occurs when the spider's mass becomes too great for the current exoskeleton to support. Male spiders seek out females for copulation and live on their webs. When mating season arrives, both males and females stop molting and remain the same size for the remainder of their lives.


Venom

The venom of the golden silk orb-weaver is effective in action on prey, but has not been reported to be of any notable consequence for humans if accidentally bitten. In the literature, ''Nephila'' is one of several genera where the venom "must be considered as more or less ineffectual in human beings". That said, the potentially large size of several members of the genus means that they possess relatively strong
chelicerae The chelicerae () are the mouthparts of the subphylum Chelicerata, an arthropod group that includes arachnids, horseshoe crabs, and sea spiders. Commonly referred to as "jaws", chelicerae may be shaped as either articulated fangs, or similarly ...
, so any bite can cause some mechanical damage, but only of short-term localised effect for humans. However, further studies of the venom components are needed to better understand pathways associated with any toxicity.


Interaction with humans

''Nephila'' do not seem to form either beneficial or harmful relationships with humans. Females often construct their webs using human structures as a base for support strands due to their stability. Individuals are often found in urban and suburban environments due to the protection from predation and greater prey availability. As they weave their webs in bushes and near flowers, they might present a nuisance for gardeners or flower pickers. Some nests near fruits may repel or destroy known pests, such as Tephritid fruit flies, without the need to use
insecticide Insecticides are substances used to kill insects. They include ovicides and larvicides used against insect eggs and larvae, respectively. Insecticides are used in agriculture, medicine, industry and by consumers. Insecticides are claimed to b ...
s. Spiders may bite humans if provoked but more often flee if confronted.


Golden silk

There have been several efforts in the past to produce garments from ''Nephila'' silk although none commercially viable.Heimer, S. (1988). Wunderbare Welt der Spinnen. ''Urania''. p.14 These include two bed hangings that were shown at the 1900 Paris Exhibition. In 2004 a textile designer, Simon Peers, and an entrepreneur, Nicholas Godley managed in three years' work and using 1.2 million Golden silk orb-weavers (collected in the wild and released some 30 minutes later after they produced the silk) to produce a shawl that was exhibited at the
American Museum of Natural History The American Museum of Natural History (abbreviated as AMNH) is a natural history museum on the Upper West Side of Manhattan in New York City. In Theodore Roosevelt Park, across the street from Central Park, the museum complex comprises 26 inter ...
in 2009. By 2012 they managed to produce a second, bigger garment, a cape, that, together with the shawl, were exhibited at the
Victoria and Albert Museum The Victoria and Albert Museum (often abbreviated as the V&A) in London is the world's largest museum of applied arts, decorative arts and design, housing a permanent collection of over 2.27 million objects. It was founded in 1852 and nam ...
in London. Two shawls and a traditional Madagascan lamba made of this spider silk were included in an exhibition of curios from the natural world in 2021. Another possible use of ''Nephila'' silk lies in
tissue engineering Tissue engineering is a biomedical engineering discipline that uses a combination of Cell (biology), cells, engineering, Materials science, materials methods, and suitable biochemistry, biochemical and physicochemical factors to restore, maintai ...
. A study from the Medizinische Hochschule Hannover reports that processed ''Nephila'' silk is an excellent scaffold material thanks to its biocompatibility, mechanical strengths, and its property to promote cell adhesion and proliferation. In particular, the silk acts as a suitable guiding material for peripheral nerve regrowth. Fishermen on the coasts of the Indo-Pacific ocean remove ''Nephila'' webs and form them into a ball, which is thrown into the water. There it unfolds and is used to catch bait fish.


See also

* List of Araneidae species: N-Z


References


External links


Pictures of golden silk orb-weavers
* {{Taxonbar, from=Q261092 Other details abou

Araneidae Extant Jurassic first appearances Pantropical spiders