Misplaced Pages

#147852

61-441: Spider webs have existed for at least 100 million years, as witnessed in a rare find of Early Cretaceous amber from Sussex , in southern England . Many spiders build webs specifically to trap and catch insects to eat. However, not all spiders catch their prey in webs, and some do not build webs at all. The term "spider web" is typically used to refer to a web that is apparently still in use (i.e., clean), whereas "cobweb" refers to

122-412: A fungicide . The effects of some drugs can be measured by examining their effects on a spider's web-building. In northeastern Nigeria , cow horn resonators in traditional xylophones often have holes covered with spider webs to create a buzzing sound. Spider web strands have been used for crosshairs or reticles in telescopes. Development of technologies to mass-produce spider silk has led to

183-458: A center-less X. Spiders in this genus also construct web decorations as vertical lines, and juveniles commonly construct disc-shaped decorations. Other spiders construct round structures covering the entire hub of the web. Some Cyclosa spiders and Azilia vachoni construct conspicuous stabilimenta with attached detritus such as egg sacs and insect carcasses (mostly their prey), and also hang debris such as dried leaves from their webs. There

244-497: A common image in tattoo art, often symbolizing long periods of time spent in prison, or used simply to fill gaps between other images. Some observers believe that a small spider is depicted on the United States one-dollar bill , in the upper-right corner of the front side ( obverse ), perched on the shield surrounding the number "1". This perception is enhanced by the resemblance of the background image of intertwining fine lines to

305-433: A day, Arabella spun the first web in the experimental cage, although it was initially incomplete. The web was completed the following day. The crew members were prompted to expand the initial protocol. They fed and watered the spiders, giving them a house fly. The first web was removed on August 13 to allow the spider to construct a second web. At first, the spider failed to construct a new web. When given more water, it built

366-406: A fine adhesive thread to drift on a faint breeze across a gap. When it sticks to a surface at the far end, the spider feels the change in the vibration. The spider reels in and tightens the first strand, then carefully walks along it and strengthens it with a second thread. This process is repeated until the thread is strong enough to support the rest of the web. After strengthening the first thread,

427-542: A horizontal plane (sheet webs), or at any angle in between. It is hypothesized that these types of aerial webs co-evolved with the evolution of winged insects. As insects are spiders' main prey, it is likely that they would impose strong selectional forces on the foraging behavior of spiders. Most commonly found in the sheet-web spider families, some webs will have loose, irregular tangles of silk above them. These tangled obstacle courses serve to disorient and knock down flying insects, making them more vulnerable to being trapped on

488-753: A phenomenon that became known as "raining spiders"; communal webs made by "social" spiders that cover such wide gaps and which strings are so difficult to see that hundreds of spiders seem to be floating in the air. The first occurred in Santo Antônio da Platina , Paraná , in 2013, and involved Anelosimus eximius individuals; the second was registered in Espírito Santo do Dourado , Minas Gerais , in January 2019, and involved Parawixia bistriata individuals. It has been observed that being in Earth's orbit has an effect on

549-417: A second web. This time, it was more elaborate than the first. Both spiders died during the mission, possibly from dehydration . When scientists were given the opportunity to study the webs, they discovered that the space webs were finer than normal Earth webs, and although the patterns of the web were not totally dissimilar, variations were spotted, and there was a definite difference in the characteristics of

610-414: A seemingly abandoned (i.e., dusty) web. However, the word "cobweb" is also used by biologists to describe the tangled three-dimensional web of some spiders of the family Theridiidae . While this large family is known as the cobweb spiders , they actually have a huge range of web architectures; other names for this spider family include tangle-web spiders and comb-footed spiders . When spiders moved from

671-682: A similar but more specific solution. He stated that the function of stabilimenta might not even be pattern or species-specific. Instead, he hypothesized that the visual signaling effect of stabilimenta might be derived from some non-signaling trait that is connected to other aspects of web-building behavior, such as silk disposition; this behavior was then selected preferentially to the specific ecological environment and therefore would be displayed through different patterns and functions among various habitats. In Cyclosa argenteoalba , web decorations were found to support Stark's hypothesis above in that they do not attract prey and instead deter predators. This

SECTION 10

#1733084756148

732-430: A spider to catch prey without having to expend energy by running it down, making it an efficient method of gathering food.The hair and claws on spiders' legs allow them to cling to their webs. The oils on their bodies keep them from sticking to their own webs. However these energy savings are somewhat offset by the fact that constructing the web is in itself energetically costly, due to the large amount of protein required in

793-411: A stylized spider web. However, other observers believe the figure is an owl. The World Wide Web is thus named because of its tangled and interlaced structure, said to resemble that of a spider web. Artificial spider webs are used by the superhero Spider-Man to restrain enemies and to make ropes on which to swing between buildings as quick transportation. Some incarnations of the character, such as

854-415: A super-tough material with the same abilities. There are a few types of spider webs found in the wild, and many spiders are classified by the webs they weave. Different types of spider webs include: Several different types of silk may be used in web construction, including a " sticky " capture silk and "fluffy" capture silk, depending on the type of spider. Webs may be in a vertical plane (most orb webs),

915-611: Is a conspicuous silk structure included in the webs of some species of orb-web spider . Its function is a subject of debate. Likely, the use of stabilimenta evolved independently at least nine different times. Araneus and Gasteracantha make silk stabilimenta, while Cyclosa and the closely related Allocyclosa bifurca make stabilimenta of silk, detritus, and their egg sacs. All those evolved independently from those of Argiope , although some decorations of Allocyclosa bifurca closely resemble those of Argiope . Although web decorations are common in several spider species in

976-428: Is much controversy surrounding the function of these structures, and different species likely use them for different purposes. Originally the decorations were thought to stabilize the web (hence the term stabilimentum ), though this hypothesis has since been dismissed because it was found that the decoration is only loosely attached to the web so that the actual influence on the stability could only be minor. Notable

1037-574: Is that the purpose of the stabilimentum is to attract the male of the species to the web when the female is ready to reproduce. A limited study carried out in the Calahonda area of Spain in the summer of 1992 showed that there was a positive correlation between the presence of a male in the webs of Argiope lobata and the presence of a stabilimentum. Many other hypotheses have also been proposed, such as thermoregulation, stress , or regulation of excess silk. At least one species has been observed to vibrate

1098-481: Is the fact that stabilimentum-building spiders are largely diurnal . It has been suggested that stabilimenta could protect the spider by either camouflaging it (by breaking up its outline) or making it appear larger (by extending its outline). Another hypothesis is that they make the web visible and therefore animals such as birds are less likely to damage the spider's web. More recent work (2016) has leaned toward this latter hypothesis, further finding that food capture

1159-637: The Late Jurassic continued to persist. Angiosperms (flowering plants) appeared for the first time during the Early Cretaceous; Archaefructaceae , one of the oldest fossil families (124.6 Ma) was found in the Yixian Formation , China. This time also saw the evolution of the first members of the Neornithes (modern birds). Sinodelphys , a 125 Ma-old boreosphenidan mammal found in

1220-812: The Panthalassic Ocean the Pacific Plate continued to grow; the Arctic Alaska-Chukotka terrane formed the Bering Strait. Continued rifting opened new basins in the Indian Ocean, separating India, Antarctica, and Australia. By 110 Ma the Mid-Atlantic Ridge reached south into the Proto-Caribbean and South Atlantic, effectively separating South America from Africa, and continued rifting in

1281-538: The Prudhoe Bay Oil Field has been interpreted as being sourced from the Triassic Shublik Formation shale and carbonate, Lower Cretaceous highly radioactive zone shale, and Lower Jurassic Kingak Shale . [REDACTED] Geology portal [REDACTED] Palaeontology portal Web decoration A stabilimentum (plural: stabilimenta ), also known as a web decoration ,

SECTION 20

#1733084756148

1342-620: The 16th century in a remote valley of the Austrian Tyrolean Alps , were created on fabrics consisting of layered and wound cobwebs, stretched over cardboard to make a mat, and strengthened by brushing with milk diluted in water. A small brush was then used to apply watercolor to the cobwebs, or custom tools to create engravings. Fewer than a hundred cobweb paintings survive today, most of which are held in private collections. In traditional European medicine, cobwebs were used on wounds and cuts to reduce bleeding and aid healing. This use

1403-506: The 2010 monsoon drove spiders above the waterline, into trees. The result was trees covered with spider webs. One such web, reported in 2007 at Lake Tawakoni State Park in Texas , measured 200 yards (180 m) across. Entomologists believe it may be the result of social cobweb spiders or of spiders building webs to spread out from one another. There is no consensus on how common this occurrence is. In Brazil, there have been two instances of

1464-627: The South Pacific at c. 120 Ma, is by far the largest LIP in Earth's history. The Ontong Java Plateau today covers an area of 1,860,000 km . In the Indian Ocean another LIP began to form at c. 120 Ma, the Kerguelen Plateau – Broken Ridge , together covering 2,300,000 km . Another LIP on the Liaodong Peninsula , China, c.  131–117 Ma, lasted for 10 million years. It

1525-564: The Yixian Formation, China, is one of the oldest mammal fossils found. The fossil location indicates early mammals began to diversify from Asia during the Early Cretaceous. Sinodelphys was more closely related to metatherians (marsupials) than eutherians (placentals) and had feet adapted for climbing trees. Steropodon is the oldest monotreme (egg-lying mammal) discovered. It lived in Gondwana (now Australia) at 105 Ma. Oil in

1586-609: The aerial webs that are familiar today. Spiders produce silk from their spinneret glands located at the tip of their abdomen . Each gland produces a thread for a special purpose – for example a trailed safety line, sticky silk for trapping prey or fine silk for wrapping it. Spiders use different gland types to produce different silks, and some spiders are capable of producing up to eight different silks during their lifetime. Most spiders have three pairs of spinnerets, each having its own function – there are also spiders with just one pair and others with as many as four pairs. Webs allow

1647-679: The banks of Newfoundland and to connect to the Canada Basin in the Arctic Ocean. With the opening of the Labrador Sea , Greenland became a separate tectonic plate and Laurentia became North America . The Proto-Caribbean Sea continued to grow and the Paraná-Etendeka LIP began to break Africa into three pieces. The Falkland Plateau broke off from southern Africa at 132 Ma and Madagascar ceased to move independently c. 120 Ma. In

1708-415: The capture silk soft and tacky. The glue balls are multifunctional – that is, their behavior depends on how quickly something touching a glue ball attempts to withdraw. At high velocities, they function as an elastic solid, resembling rubber; at lower velocities, they simply act as a sticky glue. This allows them to retain a grip on attached food particles. The web is electrically conductive which causes

1769-413: The decoration) in each population might be different depending on the prey-and-predating context of that population. For example, in an environment where the food is abundant but predation pressure is high, the food resources are less important than prey avoidance. Therefore, the stabilimentum might have little to no effect on attracting prey but functions well as a distraction from predators. Walter offered

1830-625: The exact age of the Barremian–Aptian boundary ranged from 126 to 117 Ma until recently (as of 2019), but based on drillholes in Svalbard the defining early Aptian Oceanic Anoxic Event 1a (OAE1a) was carbon isotope dated to 123.1±0.3 Ma, limiting the possible range for the boundary to c. 122–121 Ma. There is a possible link between this anoxic event and a series of Early Cretaceous large igneous provinces (LIP). The Ontong Java - Manihiki - Hikurangi large igneous province, emplaced in

1891-636: The families Araneidae , Tetragnathidae , and Uloboridae , they are probably best known from spiders of the genus Argiope . This genus includes several species known as the Saint Andrew's Cross spiders , so named for their habit of resting in their webs with their legs outstretched in the shape of an X, the traditional shape of the cross of Saint Andrew . Argiope argentata , more commonly known as silver argiopes, are also known for spinning stabilimenta into their web. These stabilimenta can appear as zig-zag lines, and most commonly come in bouts of four creating

Spider web - Misplaced Pages Continue

1952-400: The form of silk. In addition, after a time the silk will lose its stickiness and thus become inefficient at capturing prey. It is common for spiders to eat their own web daily to recoup some of the energy used in spinning. Through ingestion and digestion, the silk proteins are thus recycled.Due to the incredible strength of spider silk, scientists are currently studying it in the hope of creating

2013-575: The fragility as well as the perseverance of the protesters. The Quran uses the fragility of the spider's web as a parable , comparing it to the faith of idolators . Early Cretaceous The Early Cretaceous ( geochronological name) or the Lower Cretaceous ( chronostratigraphic name) is the earlier or lower of the two major divisions of the Cretaceous . It is usually considered to stretch from 145  Ma to 100.5 Ma. Proposals for

2074-520: The giant webs function as extended and reconfigurable auditory sensors. Not all use their webs for capturing prey directly, instead pouncing from concealment (e.g. trapdoor spiders ) or running them down in open chase (e.g. wolf spiders ). The net-casting spider balances the two methods of running and web spinning in its feeding habits. This spider weaves a small net which it attaches to its front legs. It then lurks in wait for potential prey and, when such prey arrives, lunges forward to wrap its victim in

2135-583: The impact and struggle of a prey animal by vibrations transmitted through the web. A spider positioned in the middle of the web makes for a highly visible prey for birds and other predators, even without web decorations ; many day-hunting orb-web spinners reduce this risk by hiding at the edge of the web with one foot on a signal line from the hub or by appearing to be inedible or unappetizing. Spiders do not usually adhere to their own webs, because they are able to spin both sticky and non-sticky types of silk, and are careful to travel across only non-sticky portions of

2196-407: The initial radiating lines as well as the non-sticky spirals as guide lines. The spaces between each spiral and the next are directly proportional to the distance from the tip of its back legs to its spinners. This is one way the spider uses its own body as a measuring/spacing device. While the sticky spirals are formed, the non-adhesive spirals are removed as there is no need for them any more. After

2257-471: The manufacturing of prototype military protection, wound dressings and other medical devices , and consumer goods . Spider webs can be used as a single step catalyst to make nanoparticles . The stickiness of spiders' webs is due to droplets of glue suspended on the silk threads. Orb-weaver spiders, e.g. Larinioides cornutus , coat their threads with a hygroscopic aggregate. The glue's moisture absorbing properties use environmental humidity to keep

2318-449: The net, bite and paralyze it. Hence, this spider expends less energy catching prey than a primitive hunter such as the wolf spider. It also avoids the energy loss of weaving a large orb web. Many species also spin threads of silk to catch the wind and then sail on the wind to a new location. Others manage to use the signaling-snare technique of a web without spinning a web at all. Several types of water-dwelling spiders rest their feet on

2379-589: The northern end completed the longitudinal extent of the Atlantic. In Panthalassa the Ontong-Java Mega-LIP resulted in the formation of new tectonic plates and in the Indian Ocean the Kerguelen LIP began to push India northward. During this time many new types of dinosaur appeared or came into prominence, including ceratopsians , spinosaurids , carcharodontosaurids and coelurosaurs , while survivors from

2440-401: The process of making an orb web, the spider will use its own body for measurements. There is variation in web construction among orb-weaving spiders, in particular, the species Zygiella x-notata is known for its characteristic missing sector web crossed by a single signal thread. Many webs span gaps between objects which the spider could not cross by crawling. This is done by first producing

2501-420: The radials are complete, the spider fortifies the center of the web with about five circular threads. It makes a spiral of non-sticky, widely spaced threads to enable it to move easily around its own web during construction, working from the inside outward. Then, beginning from the outside and moving inward, the spider methodically replaces this spiral with a more closely spaced one made of adhesive threads. It uses

Spider web - Misplaced Pages Continue

2562-488: The same weight of steel and much greater elasticity . Its microstructure is under investigation for potential applications in industry, including bullet-proof vests and artificial tendons . Researchers have used genetically modified mammals and bacteria to produce the proteins needed to make this material. Occasionally, a group of spiders may build webs together in the same area. Massive flooding in Pakistan during

2623-439: The silk threads to spring out to trap their quarry, as flying insects tend to gain a static charge which attracts the silk. Neurotoxins have been detected in the glue balls of some spider webs. Presumably these toxins help immobilize prey, but their function could also be antimicrobial , or protection from ants or other animals that steal from the webs or might attack the spider. Spider silk has greater tensile strength than

2684-421: The spider continues to make a Y-shaped netting. The first three radials of the web are now constructed. More radials are added, making sure that the distance between each radial and the next is small enough to cross. This means that the number of radials in a web directly depends on the size of the spider plus the size of the web. It is common for a web to be about 20 times the size of the spider building it. After

2745-416: The spider has completed its web, it chews off the initial three center spiral threads then sits and waits, usually with the head facing downwards. If the web is broken without any structural damage during the construction, the spider does not make any initial attempts to rectify the problem. The spider, after spinning its web, then waits on or near the web for a prey animal to become trapped. The spider senses

2806-406: The spider, thus protecting it from predators. Something different occurs in some species of the golden orb spiders in the genus Nephila . These spiders commonly attach lines of uneaten prey items to their webs. Recent studies have shown that these items help the spider to attract more prey. It is claimed that, after observing stabilimenta in a spider web, E. B. White came up with the idea of

2867-491: The structure of spider webs in space. Spider webs were spun in low Earth orbit in 1973 aboard Skylab , involving two female European garden spiders (cross spiders) called Arabella and Anita, as part of an experiment on the Skylab 3 mission. The aim of the experiment was to test whether the two spiders would spin webs in space, and, if so, whether these webs would be the same as those that spiders produced on Earth. The experiment

2928-458: The version in the Sam Raimi film trilogy and Spider-Man 2099 , are shown to be able to produce organic webs. The notable tensile strength of spider webs is often exaggerated in science fiction, often as a plot device to justify the presence of artificially giant spiders. Posters used by the women at Greenham Common Women's Peace Camp often featured the symbol of a spider web, meant to symbolise

2989-499: The water to the land in the Early Devonian period, they started making silk to protect their bodies and their eggs.Most Spiders have appendages called spinnerets. These are organs that produce silk with which the spiders spin webs (although some use the silk to catch their prey in other ways). Spiders gradually started using silk for hunting purposes, first as guide lines and signal lines, then as ground or bush webs, and eventually as

3050-409: The water's surface in much the same manner as an orb-web user. When an insect falls onto the water and is ensnared by surface tension , the spider can detect the vibrations and run out to capture the prey. The diving bell spider and Desis marina , an intertidal species, use their web to trap air under water, where they can stay submerged long periods of time. Cobweb paintings , which began during

3111-413: The web below. They may also help to protect the spider from predators such as birds and wasps . It is reported that several Nephila pilipes individuals can collectively construct an aggregated web system to counter bird predation from all directions. Most orb weavers construct webs in a vertical plane, although there are exceptions, such as Uloborus diversus , which builds a horizontal web. During

SECTION 50

#1733084756148

3172-409: The web, while positioned in the stabilimentum when approached by a body the size of a human. While many Uloborus species construct stabilimenta, Uloborus gibbosus does not; it usually rests at the edge of its orb and drops to the ground if disturbed. This is thought to support the web camouflage hypothesis. In contrast, the strongly UV-reflecting stabilimentum of the uloborid Octonoba sybotides

3233-416: The web. Additionally, while the webs were finer overall, the space web had variations in thickness in places: some places were slightly thinner, and others slightly thicker. This was unusual, because Earth webs have been observed to have uniform thickness. Later experiments indicated that having access to a light source could orient the spiders and enable them to build their normal asymmetric webs when gravity

3294-553: The web. However, they are not immune to their own glue. Some of the strands of the web are sticky, and others are not. For example, if a spider has chosen to wait along the outer edges of its web, it may spin a non-sticky prey or signal line to the web hub to monitor web movement. However, in the course of spinning sticky strands, spiders have to touch these sticky strands. They do this without sticking by using careful movements, dense hairs and nonstick coatings on their feet to prevent adhesion. Some spiders use their webs for hearing, where

3355-453: Was a student project of Judy Miles of Lexington, Massachusetts . After the launch on July 28, 1973, and entering Skylab, the spiders were released by astronaut Owen Garriott into a box that resembled a window frame. The spiders proceeded to construct their web while a camera took photographs and examined the spiders' behavior in a zero-gravity environment. Both spiders took a long time to adapt to their weightless existence. However, after

3416-553: Was determined through experiments where the spiders produced longer silk decorations when there was an increased predation risk, but were not affected by the amount of available prey. While the most conspicuous and well-studied decorations are constructed entirely of silk (for example in Argiope ), some spiders combine silk with other items such as egg sacs and debris (for example in Cyclosa ). It seems likely that these decorations camouflage

3477-416: Was found to be attractive to Drosophila flies. Several evolutionary models were proposed for the inconsistency in function across species. Stark argued that although these hypotheses seemingly conflict, they might not be mutually exclusive, and suggested that we could take a hierarchical approach to model this problem: the predominant factor leading to stabilimentum production (i.e., the main function of

3538-416: Was not a factor. Spider webs play a crucial role in the 1952 children's novel Charlotte's Web . Webs are also featured in many other cultural depictions of spiders . In films, illustration, and other visual arts, spider webs may be used to readily suggest a "spooky" atmosphere, or imply neglect or the passage of time. Artificial "spider webs" are a common element of Halloween decorations. Spider webs are

3599-518: Was recorded in ancient Greece and Rome, and was mentioned in Shakespeare's A Midsummer Night's Dream . Spider webs have been shown to significantly reduce wound healing times. They are rich in vitamin K , which is essential in blood clotting, and their large surface area is also thought to help coagulation. During the 1st century BC, the Roman army used spider webs as field dressings , which also served as

3660-405: Was reduced by their presence. The authors note that regardless of function, there is a high cost to building a stabilimentum, and therefore the benefit must be equally large. The other dominating hypothesis is that web decorations attract prey by reflecting ultraviolet light . Light in the ultraviolet part of the spectrum is known to be attractive to many species of insects. Another hypothesis

3721-766: Was the result of the subduction of the Kula and Pacific plates, which was probably caused by a superplume . During the opening of the South Atlantic the Paraná–Etendeka LIP produced 1.5 million km of basalts and rhyolites , beginning 133 Ma and lasting for a million years. The opening of the Central Atlantic continued as the Mid-Atlantic Ridge spread north to separate the Iberian Peninsula from

SECTION 60

#1733084756148
#147852