Spider

Spiders (order Araneae) are air-breathing arthropods that have eight legs and chelicerae with fangs able to inject venom. They are the largest order of arachnids and rank seventh in total species diversity among all orders of organisms.[2] Spiders are found worldwide on every continent except for Antarctica, and have become established in nearly every habitat with the exceptions of air and sea colonization. As of November 2015, at least 45,700 spider species, and 113 families have been recorded by taxonomists.[1] However, there has been dissension within the scientific community as to how all these families should be classified, as evidenced by the over 20 different classifications that have been proposed since 1900.[3]

Anatomically, spiders differ from other arthropods in that the usual body segments are fused into two tagmata, the cephalothorax and abdomen, and joined by a small, cylindrical pedicel. Unlike insects, spiders do not have antennae. In all except the most primitive group, the Mesothelae, spiders have the most centralized nervous systems of all arthropods, as all their ganglia are fused into one mass in the cephalothorax. Unlike most arthropods, spiders have no extensor muscles in their limbs and instead extend them by hydraulic pressure.

Their abdomens bear appendages that have been modified into spinnerets that extrude silk from up to six types of glands. Spider webs vary widely in size, shape and the amount of sticky thread used. It now appears that the spiral orb web may be one of the earliest forms, and spiders that produce tangled cobwebs are more abundant and diverse than orb-web spiders. Spider-like arachnids with silk-producing spigots appeared in the Devonian period about 386 million years ago, but these animals apparently lacked spinnerets. True spiders have been found in Carboniferous rocks from 318 to 299 million years ago, and are very similar to the most primitive surviving suborder, the Mesothelae. The main groups of modern spiders, Mygalomorphae and Araneomorphae, first appeared in the Triassic period, before 200 million years ago.

The species Bagheera kiplingi was described as herbivorous in 2008,[4] but all other known species are predators, mostly preying on insects and on other spiders, although a few large species also take birds and lizards. It is estimated that the world's 25 million tons of spiders kill 400–800 million tons of prey per year.[5] Spiders use a wide range of strategies to capture prey: trapping it in sticky webs, lassoing it with sticky bolas, mimicking the prey to avoid detection, or running it down. Most detect prey mainly by sensing vibrations, but the active hunters have acute vision, and hunters of the genus Portia show signs of intelligence in their choice of tactics and ability to develop new ones. Spiders' guts are too narrow to take solids, so they liquefy their food by flooding it with digestive enzymes. They also grind food with the bases of their pedipalps, as arachnids do not have the mandibles that crustaceans and insects have.

To avoid being eaten by the females, which are typically much larger, male spiders identify themselves to potential mates by a variety of complex courtship rituals. Males of most species survive a few matings, limited mainly by their short life spans. Females weave silk egg-cases, each of which may contain hundreds of eggs. Females of many species care for their young, for example by carrying them around or by sharing food with them. A minority of species are social, building communal webs that may house anywhere from a few to 50,000 individuals. Social behavior ranges from precarious toleration, as in the widow spiders, to co-operative hunting and food-sharing. Although most spiders live for at most two years, tarantulas and other mygalomorph spiders can live up to 25 years in captivity.

While the venom of a few species is dangerous to humans, scientists are now researching the use of spider venom in medicine and as non-polluting pesticides. Spider silk provides a combination of lightness, strength and elasticity that is superior to that of synthetic materials, and spider silk genes have been inserted into mammals and plants to see if these can be used as silk factories. As a result of their wide range of behaviors, spiders have become common symbols in art and mythology symbolizing various combinations of patience, cruelty and creative powers. An abnormal fear of spiders is called arachnophobia.

Spiders
Temporal range: PennsylvanianHolocene, 319–0 Ma
Spiders Diversity
An assortment of different spiders.
Scientific classification
Kingdom: Animalia
Phylum: Arthropoda
Subphylum: Chelicerata
Class: Arachnida
Order: Araneae
Clerck, 1757
Suborders

Mesothelae
Opisthothelae
 See Spider taxonomy.

Diversity[1]
113 families, c. 46,000 species

Description

Body plan

Palystes castaneus female dorsum numbered
Palystes castaneus female
dorsal aspect

 1: pedipalp
 2: trichobothria
 3: carapace of prosoma (cephalothorax)
 4: opisthosoma (abdomen)
 5: eyes – AL (anterior lateral)
    AM (anterior median)
    PL (posterior lateral)
    PM (posterior median)
Leg segments:
 6: costa
 7: trochanter
 8: patella
 9: tibia
10: metatarsus
11: tarsus
13: claw
14: chelicera

 
Palystes superciliosus female ventral annotation numbers
Nos 1 to 14 as for dorsal aspect

15: sternum of prosoma
16: pedicel (also called pedicle)
17: book lung sac
18: book lung stigma
19: epigastric fold
20: epigyne
21: anterior spinneret
22: posterior spinneret

I, II, III, IV = Leg numbers from anterior to posterior

Spiders are chelicerates and therefore arthropods.[6] As arthropods they have: segmented bodies with jointed limbs, all covered in a cuticle made of chitin and proteins; heads that are composed of several segments that fuse during the development of the embryo.[7] Being chelicerates, their bodies consist of two tagmata, sets of segments that serve similar functions: the foremost one, called the cephalothorax or prosoma, is a complete fusion of the segments that in an insect would form two separate tagmata, the head and thorax; the rear tagma is called the abdomen or opisthosoma.[6] In spiders, the cephalothorax and abdomen are connected by a small cylindrical section, the pedicel.[8] The pattern of segment fusion that forms chelicerates' heads is unique among arthropods, and what would normally be the first head segment disappears at an early stage of development, so that chelicerates lack the antennae typical of most arthropods. In fact, chelicerates' only appendages ahead of the mouth are a pair of chelicerae, and they lack anything that would function directly as "jaws".[7][9] The first appendages behind the mouth are called pedipalps, and serve different functions within different groups of chelicerates.[6]

Spiders and scorpions are members of one chelicerate group, the arachnids.[9] Scorpions' chelicerae have three sections and are used in feeding.[10] Spiders' chelicerae have two sections and terminate in fangs that are generally venomous, and fold away behind the upper sections while not in use. The upper sections generally have thick "beards" that filter solid lumps out of their food, as spiders can take only liquid food.[8] Scorpions' pedipalps generally form large claws for capturing prey,[10] while those of spiders are fairly small appendages whose bases also act as an extension of the mouth; in addition, those of male spiders have enlarged last sections used for sperm transfer.[8]

In spiders, the cephalothorax and abdomen are joined by a small, cylindrical pedicel, which enables the abdomen to move independently when producing silk. The upper surface of the cephalothorax is covered by a single, convex carapace, while the underside is covered by two rather flat plates. The abdomen is soft and egg-shaped. It shows no sign of segmentation, except that the primitive Mesothelae, whose living members are the Liphistiidae, have segmented plates on the upper surface.[8]

Circulation and respiration

Spider internal anatomy-en

Like other arthropods, spiders are coelomates in which the coelom is reduced to small areas round the reproductive and excretory systems. Its place is largely taken by a hemocoel, a cavity that runs most of the length of the body and through which blood flows. The heart is a tube in the upper part of the body, with a few ostia that act as non-return valves allowing blood to enter the heart from the hemocoel but prevent it from leaving before it reaches the front end.[11] However, in spiders, it occupies only the upper part of the abdomen, and blood is discharged into the hemocoel by one artery that opens at the rear end of the abdomen and by branching arteries that pass through the pedicle and open into several parts of the cephalothorax. Hence spiders have open circulatory systems.[8] The blood of many spiders that have book lungs contains the respiratory pigment hemocyanin to make oxygen transport more efficient.[9]

Spiders have developed several different respiratory anatomies, based on book lungs, a tracheal system, or both. Mygalomorph and Mesothelae spiders have two pairs of book lungs filled with haemolymph, where openings on the ventral surface of the abdomen allow air to enter and diffuse oxygen. This is also the case for some basal araneomorph spiders, like the family Hypochilidae, but the remaining members of this group have just the anterior pair of book lungs intact while the posterior pair of breathing organs are partly or fully modified into tracheae, through which oxygen is diffused into the haemolymph or directly to the tissue and organs.[8] The trachea system has most likely evolved in small ancestors to help resist desiccation.[9] The trachea were originally connected to the surroundings through a pair of openings called spiracles, but in the majority of spiders this pair of spiracles has fused into a single one in the middle, and moved backwards close to the spinnerets.[8] Spiders that have tracheae generally have higher metabolic rates and better water conservation.[12] Spiders are ectotherms, so environmental temperatures affect their activity.[13]

Fly captured by spider in web
A syrphid fly captured in the web of a spider

Feeding, digestion and excretion

Cheiracanthium punctorium frei 1 17 Forst Jungfernhdeide Jg 46 070920
Cheiracanthium punctorium, displaying fangs

Uniquely among chelicerates, the final sections of spiders' chelicerae are fangs, and the great majority of spiders can use them to inject venom into prey from venom glands in the roots of the chelicerae.[8] The families Uloboridae and Holarchaeidae, and some Liphistiidae spiders, have lost their venom glands, and kill their prey with silk instead.[14] Like most arachnids, including scorpions,[9] spiders have a narrow gut that can only cope with liquid food and two sets of filters to keep solids out.[8] They use one of two different systems of external digestion. Some pump digestive enzymes from the midgut into the prey and then suck the liquified tissues of the prey into the gut, eventually leaving behind the empty husk of the prey. Others grind the prey to pulp using the chelicerae and the bases of the pedipalps, while flooding it with enzymes; in these species, the chelicerae and the bases of the pedipalps form a preoral cavity that holds the food they are processing.[8]

The stomach in the cephalothorax acts as a pump that sends the food deeper into the digestive system. The mid gut bears many digestive ceca, compartments with no other exit, that extract nutrients from the food; most are in the abdomen, which is dominated by the digestive system, but a few are found in the cephalothorax.[8]

Most spiders convert nitrogenous waste products into uric acid, which can be excreted as a dry material. Malphigian tubules ("little tubes") extract these wastes from the blood in the hemocoel and dump them into the cloacal chamber, from which they are expelled through the anus.[8] Production of uric acid and its removal via Malphigian tubules are a water-conserving feature that has evolved independently in several arthropod lineages that can live far away from water,[15] for example the tubules of insects and arachnids develop from completely different parts of the embryo.[9] However, a few primitive spiders, the sub-order Mesothelae and infra-order Mygalomorphae, retain the ancestral arthropod nephridia ("little kidneys"),[8] which use large amounts of water to excrete nitrogenous waste products as ammonia.[15]

Central nervous system

The basic arthropod central nervous system consists of a pair of nerve cords running below the gut, with paired ganglia as local control centers in all segments; a brain formed by fusion of the ganglia for the head segments ahead of and behind the mouth, so that the esophagus is encircled by this conglomeration of ganglia.[16] Except for the primitive Mesothelae, of which the Liphistiidae are the sole surviving family, spiders have the much more centralized nervous system that is typical of arachnids: all the ganglia of all segments behind the esophagus are fused, so that the cephalothorax is largely filled with nervous tissue and there are no ganglia in the abdomen;[8][9][16] in the Mesothelae, the ganglia of the abdomen and the rear part of the cephalothorax remain unfused.[12]

Despite the relatively small central nervous system, some spiders (like Portia) exhibit complex behaviour, including the ability to use a trial-and-error approach.[17][18]

Sense organs

Eyes

Clynotis severus, AF 2
This jumping spider's main ocelli (center pair) are very acute. The outer pair are "secondary eyes" and there are other pairs of secondary eyes on the sides and top of its head.[19]

Spiders have primarily four pairs of eyes on the top-front area of the cephalothorax, arranged in patterns that vary from one family to another.[8] The principal pair at the front are of the type called pigment-cup ocelli ("little eyes"), which in most arthropods are only capable of detecting the direction from which light is coming, using the shadow cast by the walls of the cup. However, in spiders these eyes are capable of forming images.[19][20] The other pairs, called secondary eyes, are thought to be derived from the compound eyes of the ancestral chelicerates, but no longer have the separate facets typical of compound eyes. Unlike the principal eyes, in many spiders these secondary eyes detect light reflected from a reflective tapetum lucidum, and wolf spiders can be spotted by torch light reflected from the tapeta. On the other hand, jumping spiders' secondary eyes have no tapeta.[8]

Other differences between the principal and secondary eyes are that the latter have rhabdomeres that point away from incoming light, just like in vertebrates, while the arrangement is the opposite in the former. The principal eyes are also the only ones with eye muscles, allowing them to move the retina. Having no muscles, the secondary eyes are immobile.[21]

Some jumping spiders' visual acuity exceeds by a factor of ten that of dragonflies, which have by far the best vision among insects; in fact the human eye is only about five times sharper than a jumping spider's. They achieve this by a telephoto-like series of lenses, a four-layer retina and the ability to swivel their eyes and integrate images from different stages in the scan. The downside is that the scanning and integrating processes are relatively slow.[17]

There are spiders with a reduced number of eyes. Of these, those with six eyes are the most numerous and are missing a pair of eyes on the anterior median line;[22] other species have four eyes and some just two. Cave dwelling species have no eyes, or possess vestigial eyes incapable of sight.

Other senses

As with other arthropods, spiders' cuticles would block out information about the outside world, except that they are penetrated by many sensors or connections from sensors to the nervous system. In fact, spiders and other arthropods have modified their cuticles into elaborate arrays of sensors. Various touch sensors, mostly bristles called setae, respond to different levels of force, from strong contact to very weak air currents. Chemical sensors provide equivalents of taste and smell, often by means of setae.[19] An adult Araneus may have up to 1000 such chemosensitive setae, most on the tarsi of the first pair of legs. Males have more chemosensitive hairs on their pedipalps than females. They have been shown to be responsive to sex pheromones produced by females, both contact and air-borne.[23] Spiders also have in the joints of their limbs slit sensillae that detects force and vibrations. In web-building spiders, all these mechanical and chemical sensors are more important than the eyes, while the eyes are most important to spiders that hunt actively.[8]

Like most arthropods, spiders lack balance and acceleration sensors and rely on their eyes to tell them which way is up. Arthropods' proprioceptors, sensors that report the force exerted by muscles and the degree of bending in the body and joints, are well understood. On the other hand, little is known about what other internal sensors spiders or other arthropods may have.[19]

Locomotion

Aranna pata
Image of a spider leg: 1–coxa; 2–trochanter; 3–femur; 4–patella; 5–tibia; 6–metatarsus; 7–tarsus; 8–claws

Each of the eight legs of a spider consists of seven distinct parts. The part closest to and attaching the leg to the cephalothorax is the coxa; the next segment is the short trochanter that works as a hinge for the following long segment, the femur; next is the spider's knee, the patella, which acts as the hinge for the tibia; the metatarsus is next, and it connects the tibia to the tarsus (which may be thought of as a foot of sorts); the tarsus ends in a claw made up of either two or three points, depending on the family to which the spider belongs. Although all arthropods use muscles attached to the inside of the exoskeleton to flex their limbs, spiders and a few other groups still use hydraulic pressure to extend them, a system inherited from their pre-arthropod ancestors.[24] The only extensor muscles in spider legs are located in the three hip joints (bordering the coxa and the trochanter).[25] As a result, a spider with a punctured cephalothorax cannot extend its legs, and the legs of dead spiders curl up.[8] Spiders can generate pressures up to eight times their resting level to extend their legs,[26] and jumping spiders can jump up to 50 times their own length by suddenly increasing the blood pressure in the third or fourth pair of legs.[8] Although larger spiders use hydraulics to straighten their legs, unlike smaller jumping spiders they depend on their flexor muscles to generate the propulsive force for their jumps.[25]

Most spiders that hunt actively, rather than relying on webs, have dense tufts of fine hairs between the paired claws at the tips of their legs. These tufts, known as scopulae, consist of bristles whose ends are split into as many as 1,000 branches, and enable spiders with scopulae to walk up vertical glass and upside down on ceilings. It appears that scopulae get their grip from contact with extremely thin layers of water on surfaces.[8] Spiders, like most other arachnids, keep at least four legs on the surface while walking or running.[27]

Silk production

Australian orb weaver spinning web
An orb weaver producing silk from its spinnerets

The abdomen has no appendages except those that have been modified to form one to four (usually three) pairs of short, movable spinnerets, which emit silk. Each spinneret has many spigots, each of which is connected to one silk gland. There are at least six types of silk gland, each producing a different type of silk.[8]

Silk is mainly composed of a protein very similar to that used in insect silk. It is initially a liquid, and hardens not by exposure to air but as a result of being drawn out, which changes the internal structure of the protein.[28] It is similar in tensile strength to nylon and biological materials such as chitin, collagen and cellulose, but is much more elastic. In other words, it can stretch much further before breaking or losing shape.[8]

Some spiders have a cribellum, a modified spinneret with up to 40,000 spigots, each of which produces a single very fine fiber. The fibers are pulled out by the calamistrum, a comb-like set of bristles on the jointed tip of the cribellum, and combined into a composite woolly thread that is very effective in snagging the bristles of insects. The earliest spiders had cribella, which produced the first silk capable of capturing insects, before spiders developed silk coated with sticky droplets. However, most modern groups of spiders have lost the cribellum.[8]

Tarantulas also have silk glands in their feet.[29]

Even species that do not build webs to catch prey use silk in several ways: as wrappers for sperm and for fertilized eggs; as a "safety rope"; for nest-building; and as "parachutes" by the young of some species.[8]

Reproduction and life cycle

Mating behaviour of Neriene radiata
DirkvdM Nephila clavipes
The tiny male of the Golden orb weaver (Nephila clavipes) (near the top of the leaf) is protected from the female by his producing the right vibrations in the web, and may be too small to be worth eating.

Spiders reproduce sexually and fertilization is internal but indirect, in other words the sperm is not inserted into the female's body by the male's genitals but by an intermediate stage. Unlike many land-living arthropods,[30] male spiders do not produce ready-made spermatophores (packages of sperm), but spin small sperm webs on to which they ejaculate and then transfer the sperm to special syringe-like structures, palpal bulbs or palpal organs, borne on the tips of the pedipalps of mature males. When a male detects signs of a female nearby he checks whether she is of the same species and whether she is ready to mate; for example in species that produce webs or "safety ropes", the male can identify the species and sex of these objects by "smell".[8]

Spiders generally use elaborate courtship rituals to prevent the large females from eating the small males before fertilization, except where the male is so much smaller that he is not worth eating. In web-weaving species, precise patterns of vibrations in the web are a major part of the rituals, while patterns of touches on the female's body are important in many spiders that hunt actively, and may "hypnotize" the female. Gestures and dances by the male are important for jumping spiders, which have excellent eyesight. If courtship is successful, the male injects his sperm from the palpal bulbs into the female's genital opening, known as the epigyne, on the underside of her abdomen. Female's reproductive tracts vary from simple tubes to systems that include seminal receptacles in which females store sperm and release it when they are ready.[8] Because the sperm is stored in the epigyne, the eggs are not fertilized while inside the female, but during oviposition when the stored sperm is released from its chamber. The only known exception is a spider from Israel, Harpactea sadistica, which has evolved traumatic insemination. In this species the male will penetrate its pedipalps through the female's body wall and inject his sperm directly into her ovaries, where the embryos inside the fertilized eggs will start to develop before being laid.[31]

Males of the genus Tidarren amputate one of their palps before maturation and enter adult life with one palp only. The palps are 20% of male's body mass in this species, and detaching one of the two improves mobility. In the Yemeni species Tidarren argo, the remaining palp is then torn off by the female. The separated palp remains attached to the female's epigynum for about four hours and apparently continues to function independently. In the meantime, the female feeds on the palpless male.[32] In over 60% of cases, the female of the Australian redback spider kills and eats the male after it inserts its second palp into the female's genital opening; in fact, the males co-operate by trying to impale themselves on the females' fangs. Observation shows that most male redbacks never get an opportunity to mate, and the "lucky" ones increase the likely number of offspring by ensuring that the females are well-fed.[33] However, males of most species survive a few matings, limited mainly by their short life spans. Some even live for a while in their mates' webs.[34]

Orange spider egg sac

Orange spider egg sac hanging from ceiling

Gasteracantha mammosa spiderlings next to their eggs capsule

Gasteracantha mammosa spiderlings next to their eggs capsule

Lycosidae female carrying young

Wolf spider carrying its young on its abdomen

Females lay up to 3,000 eggs in one or more silk egg sacs,[8] which maintain a fairly constant humidity level.[34] In some species, the females die afterwards, but females of other species protect the sacs by attaching them to their webs, hiding them in nests, carrying them in the chelicerae or attaching them to the spinnerets and dragging them along.[8]

Baby spiders pass all their larval stages inside the egg and hatch as spiderlings, very small and sexually immature but similar in shape to adults. Some spiders care for their young, for example a wolf spider's brood cling to rough bristles on the mother's back,[8] and females of some species respond to the "begging" behaviour of their young by giving them their prey, provided it is no longer struggling, or even regurgitate food.[34]

Like other arthropods, spiders have to molt to grow as their cuticle ("skin") cannot stretch.[35] In some species males mate with newly molted females, which are too weak to be dangerous to the males.[34] Most spiders live for only one to two years, although some tarantulas can live in captivity for over 20 years,[8][36] and an Australian female trapdoor spider was documented to have lived in the wild for 43 years, dying of a parasitic wasp attack.[37]

Size

Theraphosa blondi MHNT
Goliath birdeater (Theraphosa blondi), the largest spider

Spiders occur in a large range of sizes. The smallest, Patu digua from Colombia, are less than 0.37 mm (0.015 in) in body length. The largest and heaviest spiders occur among tarantulas, which can have body lengths up to 90 mm (3.5 in) and leg spans up to 250 mm (9.8 in).[38]

Coloration

Only three classes of pigment (ommochromes, bilins and guanine) have been identified in spiders, although other pigments have been detected but not yet characterized. Melanins, carotenoids and pterins, very common in other animals, are apparently absent. In some species, the exocuticle of the legs and prosoma is modified by a tanning process, resulting in brown coloration.[39] Bilins are found, for example, in Micrommata virescens, resulting in its green color. Guanine is responsible for the white markings of the European garden spider Araneus diadematus. It is in many species accumulated in specialized cells called guanocytes. In genera such as Tetragnatha, Leucauge, Argyrodes or Theridiosoma, guanine creates their silvery appearance. While guanine is originally an end-product of protein metabolism, its excretion can be blocked in spiders, leading to an increase in its storage.[39] Structural colors occur in some species, which are the result of the diffraction, scattering or interference of light, for example by modified setae or scales. The white prosoma of Argiope results from hairs reflecting the light, Lycosa and Josa both have areas of modified cuticle that act as light reflectors.[39]

Ecology and behavior

Non-predatory feeding

Although spiders are generally regarded as predatory, the jumping spider Bagheera kiplingi gets over 90% of its food from fairly solid plant material produced by acacias as part of a mutually beneficial relationship with a species of ant.[40]

Juveniles of some spiders in the families Anyphaenidae, Corinnidae, Clubionidae, Thomisidae and Salticidae feed on plant nectar. Laboratory studies show that they do so deliberately and over extended periods, and periodically clean themselves while feeding. These spiders also prefer sugar solutions to plain water, which indicates that they are seeking nutrients. Since many spiders are nocturnal, the extent of nectar consumption by spiders may have been underestimated. Nectar contains amino acids, lipids, vitamins and minerals in addition to sugars, and studies have shown that other spider species live longer when nectar is available. Feeding on nectar avoids the risks of struggles with prey, and the costs of producing venom and digestive enzymes.[41]

Various species are known to feed on dead arthropods (scavenging), web silk, and their own shed exoskeletons. Pollen caught in webs may also be eaten, and studies have shown that young spiders have a better chance of survival if they have the opportunity to eat pollen. In captivity, several spider species are also known to feed on bananas, marmalade, milk, egg yolk and sausages.[41]

Capturing prey

Spider house leaf
The Phonognatha graeffei or leaf-curling spider's web serves both as a trap and as a way of making its home in a leaf.

The best-known method of prey capture is by means of sticky webs. Varying placement of webs allows different species of spider to trap different insects in the same area, for example flat horizontal webs trap insects that fly up from vegetation underneath while flat vertical webs trap insects in horizontal flight. Web-building spiders have poor vision, but are extremely sensitive to vibrations.[8]

Females of the water spider Argyroneta aquatica build underwater "diving bell" webs that they fill with air and use for digesting prey, molting, mating and raising offspring. They live almost entirely within the bells, darting out to catch prey animals that touch the bell or the threads that anchor it.[42] A few spiders use the surfaces of lakes and ponds as "webs", detecting trapped insects by the vibrations that these cause while struggling.[8]

Net-casting spiders weave only small webs, but then manipulate them to trap prey. Those of the genus Hyptiotes and the family Theridiosomatidae stretch their webs and then release them when prey strike them, but do not actively move their webs. Those of the family Deinopidae weave even smaller webs, hold them outstretched between their first two pairs of legs, and lunge and push the webs as much as twice their own body length to trap prey, and this move may increase the webs' area by a factor of up to ten. Experiments have shown that Deinopis spinosus has two different techniques for trapping prey: backwards strikes to catch flying insects, whose vibrations it detects; and forward strikes to catch ground-walking prey that it sees. These two techniques have also been observed in other deinopids. Walking insects form most of the prey of most deinopids, but one population of Deinopis subrufa appears to live mainly on tipulid flies that they catch with the backwards strike.[43]

Mature female bolas spiders of the genus Mastophora build "webs" that consist of only a single "trapeze line", which they patrol. They also construct a bolas made of a single thread, tipped with a large ball of very wet sticky silk. They emit chemicals that resemble the pheromones of moths, and then swing the bolas at the moths. Although they miss on about 50% of strikes, they catch about the same weight of insects per night as web-weaving spiders of similar size. The spiders eat the bolas if they have not made a kill in about 30 minutes, rest for a while, and then make new bolas.[44][45] Juveniles and adult males are much smaller and do not make bolas. Instead they release different pheromones that attract moth flies, and catch them with their front pairs of legs.[46]

Cyclocosmia sp. in burrow (Marshal Hedin)
A trapdoor spider in the genus Cyclocosmia, an ambush predator

The primitive Liphistiidae, the "trapdoor spiders" of the family Ctenizidae and many tarantulas are ambush predators that lurk in burrows, often closed by trapdoors and often surrounded by networks of silk threads that alert these spiders to the presence of prey.[12] Other ambush predators do without such aids, including many crab spiders,[8] and a few species that prey on bees, which see ultraviolet, can adjust their ultraviolet reflectance to match the flowers in which they are lurking.[39] Wolf spiders, jumping spiders, fishing spiders and some crab spiders capture prey by chasing it, and rely mainly on vision to locate prey.[8]

Portia.fimbriata.female.in.its.web.-.tanikawa
Portia uses both webs and cunning, versatile tactics to overcome prey.[47]

Some jumping spiders of the genus Portia hunt other spiders in ways that seem intelligent,[17] outflanking their victims or luring them from their webs. Laboratory studies show that Portia's instinctive tactics are only starting points for a trial-and-error approach from which these spiders learn very quickly how to overcome new prey species.[47] However, they seem to be relatively slow "thinkers", which is not surprising, as their brains are vastly smaller than those of mammalian predators.[17]

Ant-mimicking spiders face several challenges: they generally develop slimmer abdomens and false "waists" in the cephalothorax to mimic the three distinct regions (tagmata) of an ant's body; they wave the first pair of legs in front of their heads to mimic antennae, which spiders lack, and to conceal the fact that they have eight legs rather than six; they develop large color patches round one pair of eyes to disguise the fact that they generally have eight simple eyes, while ants have two compound eyes; they cover their bodies with reflective hairs to resemble the shiny bodies of ants. In some spider species, males and females mimic different ant species, as female spiders are usually much larger than males. Ant-mimicking spiders also modify their behavior to resemble that of the target species of ant; for example, many adopt a zig-zag pattern of movement, ant-mimicking jumping spiders avoid jumping, and spiders of the genus Synemosyna walk on the outer edges of leaves in the same way as Pseudomyrmex. Ant-mimicry in many spiders and other arthropods may be for protection from predators that hunt by sight, including birds, lizards and spiders. However, several ant-mimicking spiders prey either on ants or on the ants' "livestock", such as aphids. When at rest, the ant-mimicking crab spider Amyciaea does not closely resemble Oecophylla, but while hunting it imitates the behavior of a dying ant to attract worker ants. After a kill, some ant-mimicking spiders hold their victims between themselves and large groups of ants to avoid being attacked.[48]

Defense

Atrax robustus
Threat display by a Sydney funnel-web spider (Atrax robustus).

There is strong evidence that spiders' coloration is camouflage that helps them to evade their major predators, birds and parasitic wasps, both of which have good color vision. Many spider species are colored so as to merge with their most common backgrounds, and some have disruptive coloration, stripes and blotches that break up their outlines. In a few species, such as the Hawaiian happy-face spider, Theridion grallator, several coloration schemes are present in a ratio that appears to remain constant, and this may make it more difficult for predators to recognize the species. Most spiders are insufficiently dangerous or unpleasant-tasting for warning coloration to offer much benefit. However, a few species with powerful venoms, large jaws or irritant hairs have patches of warning colors, and some actively display these colors when threatened.[39][49]

Many of the family Theraphosidae, which includes tarantulas and baboon spiders, have urticating hairs on their abdomens and use their legs to flick them at attackers. These hairs are fine setae (bristles) with fragile bases and a row of barbs on the tip. The barbs cause intense irritation but there is no evidence that they carry any kind of venom.[50] A few defend themselves against wasps by including networks of very robust threads in their webs, giving the spider time to flee while the wasps are struggling with the obstacles.[51] The golden wheeling spider, Carparachne aureoflava, of the Namibian desert escapes parasitic wasps by flipping onto its side and cartwheeling down sand dunes.[52]

Socialization

A few spider species that build webs live together in large colonies and show social behavior, although not as complex as in social insects. Anelosimus eximius (in the family Theridiidae) can form colonies of up to 50,000 individuals.[53] The genus Anelosimus has a strong tendency towards sociality: all known American species are social, and species in Madagascar are at least somewhat social.[54] Members of other species in the same family but several different genera have independently developed social behavior. For example, although Theridion nigroannulatum belongs to a genus with no other social species, T. nigroannulatum build colonies that may contain several thousand individuals that co-operate in prey capture and share food.[55] Other communal spiders include several Philoponella species (family Uloboridae), Agelena consociata (family Agelenidae) and Mallos gregalis (family Dictynidae).[56] Social predatory spiders need to defend their prey against kleptoparasites ("thieves"), and larger colonies are more successful in this.[57] The herbivorous spider Bagheera kiplingi lives in small colonies which help to protect eggs and spiderlings.[40] Even widow spiders (genus Latrodectus), which are notoriously cannibalistic, have formed small colonies in captivity, sharing webs and feeding together.[58]

Web types

Araneus diadematus web 1
The large orb web of Araneus diadematus (European garden spider).

There is no consistent relationship between the classification of spiders and the types of web they build: species in the same genus may build very similar or significantly different webs. Nor is there much correspondence between spiders' classification and the chemical composition of their silks. Convergent evolution in web construction, in other words use of similar techniques by remotely related species, is rampant. Orb web designs and the spinning behaviors that produce them are the best understood. The basic radial-then-spiral sequence visible in orb webs and the sense of direction required to build them may have been inherited from the common ancestors of most spider groups.[59] However, the majority of spiders build non-orb webs. It used to be thought that the sticky orb web was an evolutionary innovation resulting in the diversification of the Orbiculariae. Now, however, it appears that non-orb spiders are a sub-group that evolved from orb-web spiders, and non-orb spiders have over 40% more species and are four times as abundant as orb-web spiders. Their greater success may be because sphecid wasps, which are often the dominant predators of spiders, much prefer to attack spiders that have flat webs.[60]

Orb

NephilaClavata-2005Kurihara
Nephila clavata, a golden orb weaver

About half the potential prey that hit orb webs escape. A web has to perform three functions: intercepting the prey (intersection), absorbing its momentum without breaking (stopping), and trapping the prey by entangling it or sticking to it (retention). No single design is best for all prey. For example: wider spacing of lines will increase the web's area and hence its ability to intercept prey, but reduce its stopping power and retention; closer spacing, larger sticky droplets and thicker lines would improve retention, but would make it easier for potential prey to see and avoid the web, at least during the day. However, there are no consistent differences between orb webs built for use during the day and those built for use at night. In fact, there is no simple relationship between orb web design features and the prey they capture, as each orb-weaving species takes a wide range of prey.[59]

The hubs of orb webs, where the spiders lurk, are usually above the center, as the spiders can move downwards faster than upwards. If there is an obvious direction in which the spider can retreat to avoid its own predators, the hub is usually offset towards that direction.[59]

Horizontal orb webs are fairly common, despite being less effective at intercepting and retaining prey and more vulnerable to damage by rain and falling debris. Various researchers have suggested that horizontal webs offer compensating advantages, such as reduced vulnerability to wind damage; reduced visibility to prey flying upwards, because of the back-lighting from the sky; enabling oscillations to catch insects in slow horizontal flight. However, there is no single explanation for the common use of horizontal orb webs.[59]

Spiders often attach highly visible silk bands, called decorations or stabilimenta, to their webs. Field research suggests that webs with more decorative bands captured more prey per hour.[61] However, a laboratory study showed that spiders reduce the building of these decorations if they sense the presence of predators.[62]

There are several unusual variants of orb web, many of them convergently evolved, including: attachment of lines to the surface of water, possibly to trap insects in or on the surface; webs with twigs through their centers, possibly to hide the spiders from predators; "ladder-like" webs that appear most effective in catching moths. However, the significance of many variations is unclear.[59]

In 1973, Skylab 3 took two orb-web spiders into space to test their web-spinning capabilities in zero gravity. At first, both produced rather sloppy webs, but they adapted quickly.[63]

Cobweb

Agelenidae labyrinthica
A funnel web.

Members of the family Theridiidae weave irregular, tangled, three-dimensional webs, popularly known as cobwebs. There seems to be an evolutionary trend towards a reduction in the amount of sticky silk used, leading to its total absence in some species. The construction of cobwebs is less stereotyped than that of orb-webs, and may take several days.[60]

Other

The Linyphiidae generally make horizontal but uneven sheets, with tangles of stopping threads above. Insects that hit the stopping threads fall onto the sheet or are shaken onto it by the spider, and are held by sticky threads on the sheet until the spider can attack from below.[64]

Evolution

Fossil record

Spider in amber (1)
Spider preserved in amber

Although the fossil record of spiders is considered poor,[65] almost 1000 species have been described from fossils.[66] Because spiders' bodies are quite soft, the vast majority of fossil spiders have been found preserved in amber.[66] The oldest known amber that contains fossil arthropods dates from 130 million years ago in the Early Cretaceous period. In addition to preserving spiders' anatomy in very fine detail, pieces of amber show spiders mating, killing prey, producing silk and possibly caring for their young. In a few cases, amber has preserved spiders' egg sacs and webs, occasionally with prey attached;[67] the oldest fossil web found so far is 100 million years old.[68] Earlier spider fossils come from a few lagerstätten, places where conditions were exceptionally suited to preserving fairly soft tissues.[67]

The oldest known exclusively terrestrial arachnid is the trigonotarbid Palaeotarbus jerami, from about 420 million years ago in the Silurian period, and had a triangular cephalothorax and segmented abdomen, as well as eight legs and a pair of pedipalps.[69] Attercopus fimbriunguis, from 386 million years ago in the Devonian period, bears the earliest known silk-producing spigots, and was therefore hailed as a spider at the time of its discovery.[70] However, these spigots may have been mounted on the underside of the abdomen rather than on spinnerets, which are modified appendages and whose mobility is important in the building of webs. Hence Attercopus and the similar Permian arachnid Permarachne may not have been true spiders, and probably used silk for lining nests or producing egg-cases rather than for building webs.[71] The largest known fossil spider as of 2011 is the araneid Nephila jurassica, from about 165 million years ago, recorded from Daohuogo, Inner Mongolia in China.[72] Its body length is almost 25 mm, (i.e., almost one inch).

Several Carboniferous spiders were members of the Mesothelae, a primitive group now represented only by the Liphistiidae.[70] The mesothelid Paleothele montceauensis, from the Late Carboniferous over 299 million years ago, had five spinnerets.[73] Although the Permian period 299 to 251 million years ago saw rapid diversification of flying insects, there are very few fossil spiders from this period.[70]

The main groups of modern spiders, Mygalomorphae and Araneomorphae, first appear in the Triassic well before 200 million years ago. Some Triassic mygalomorphs appear to be members of the family Hexathelidae, whose modern members include the notorious Sydney funnel-web spider, and their spinnerets appear adapted for building funnel-shaped webs to catch jumping insects. Araneomorphae account for the great majority of modern spiders, including those that weave the familiar orb-shaped webs. The Jurassic and Cretaceous periods provide a large number of fossil spiders, including representatives of many modern families.[70]

Family tree

It is now agreed that spiders (Araneae) are monophyletic (i.e., members of a group of organisms that form a clade, consisting of a last common ancestor and all of its descendants).[75] There has been debate about what their closest evolutionary relatives are, and how all of these evolved from the ancestral chelicerates, which were marine animals. The cladogram on the right is based on J. W. Shultz' analysis (2007). Other views include proposals that: scorpions are more closely related to the extinct marine scorpion-like eurypterids than to spiders; spiders and Amblypygi are a monophyletic group. The appearance of several multi-way branchings in the tree on the right shows that there are still uncertainties about relationships between the groups involved.[75]

Arachnids lack some features of other chelicerates, including backward-pointing mouths and gnathobases ("jaw bases") at the bases of their legs;[75] both of these features are part of the ancestral arthropod feeding system.[76] Instead, they have mouths that point forwards and downwards, and all have some means of breathing air.[75] Spiders (Araneae) are distinguished from other arachnid groups by several characteristics, including spinnerets and, in males, pedipalps that are specially adapted for sperm transfer.[77]

Taxonomy

Spiders are divided into two suborders, Mesothelae and Opisthothelae, of which the latter contains two infraorders, Mygalomorphae and Araneomorphae. Nearly 46,000 living species of spiders (order Araneae) have been identified and as of 2009 grouped into about 117 families and about 4,100 genera by arachnologists.[1]

  Spider diversity[1][77]
(numbers are approximate)
Features
Suborder/Infraorder Families Genera Species Segmented plates on top of abdomen[78] Ganglia in abdomen Spinnerets[78] Striking direction of fangs[8]
Mesothelae 1 8 116 Yes Yes Four pairs, in some species one pair fused, under middle of abdomen Downwards and forwards
Opisthothelae: Mygalomorphae 20 350 2,900 Only in some fossils No One, two or three pairs under rear of abdomen
Opisthothelae: Araneomorphae 96 3,700 44,000 From sides to center, like pincers

Mesothelae

The only living members of the primitive Mesothelae are the family Liphistiidae, found only in Southeast Asia, China, and Japan.[77] Most of the Liphistiidae construct silk-lined burrows with thin trapdoors, although some species of the genus Liphistius build camouflaged silk tubes with a second trapdoor as an emergency exit. Members of the genus Liphistius run silk "tripwires" outwards from their tunnels to help them detect approaching prey, while those of genus Heptathela do not and instead rely on their built-in vibration sensors.[80] Spiders of the genus Heptathela have no venom glands although they do have venom gland outlets on the fang tip.[81]

The extinct families Arthrolycosidae, found in Carboniferous and Permian rocks, and Arthromygalidae, so far found only in Carboniferous rocks, have been classified as members of the Mesothelae.[82]

Mygalomorphae

Tarantula 020
A Mexican red-kneed tarantula Brachypelma smithi

The Mygalomorphae, which first appeared in the Triassic period,[70] are generally heavily built and hairy, with large, robust chelicerae and fangs.[77] Well-known examples include tarantulas, ctenizid trapdoor spiders and the Australasian funnel-web spiders.[8] Most spend the majority of their time in burrows, and some run silk tripwires out from these, but a few build webs to capture prey. However, mygalomorphs cannot produce the pirifom silk that the Araneomorphae use as instant adhesive to glue silk to surfaces or to other strands of silk, and this makes web construction more difficult for mygalomorphs. Since mygalomorphs rarely "balloon" by using air currents for transport, their populations often form clumps.[77] In addition to arthropods, mygalomorphs are capable of preying on frogs, small mammals, lizards, and snails.[83]

Araneomorphae

In addition to accounting for over 90% of spider species, the Araneomorphae, also known as the "true spiders", include orb-web spiders, the cursorial wolf spiders, and jumping spiders,[77] as well as the only known herbivorous spider, Bagheera kiplingi.[40] They are distinguished by having fangs that oppose each other and cross in a pinching action, in contrast to the Mygalomorphae, which have fangs that are nearly parallel in alignment.[84]

Human interaction

Bites

Symptoms of Spider bite
All symptoms associated with toxic spider bites[85]

Although spiders are widely feared, only a few species are dangerous to people.[86] Spiders will only bite humans in self-defense, and few produce worse effects than a mosquito bite or bee-sting.[87] Most of those with medically serious bites, such as recluse spiders (genus Loxosceles) and widow spiders (genus Latrodectus), would rather flee and bite only when trapped, although this can easily arise by accident.[88][89] The defensive tactics of Australian funnel-web spiders (family Atracidae) include fang display. Their venom, although they rarely inject much, has resulted in 13 attributed human deaths over 50 years.[90] They have been deemed to be the world's most dangerous spiders on clinical and venom toxicity grounds,[86] though this claim has also been attributed to the Brazilian wandering spider (genus Phoneutria).[91]

There were about 100 reliably reported deaths from spider bites in the 20th century,[92] compared to about 1,500 from jellyfish stings.[93] Many alleged cases of spider bites may represent incorrect diagnoses,[94] which would make it more difficult to check the effectiveness of treatments for genuine bites.[95] A review published in 2016 agreed with this conclusion, showing that 78% of 134 published medical case studies of supposed spider bites did not meet the necessary criteria for a spider bite to be verified. In the case of the two genera with the highest reported number of bites, Loxosceles and Latrodectus, spider bites were not verified in over 90% of the reports. Even when verification had occurred, details of the treatment and its effects were often lacking.[96]

Chemical benefits

Fried spiders Skuon Cambodia
Cooked tarantula spiders are considered a delicacy in Cambodia.

Spider venoms may be a less polluting alternative to conventional pesticides, as they are deadly to insects but the great majority are harmless to vertebrates. Australian funnel web spiders are a promising source, as most of the world's insect pests have had no opportunity to develop any immunity to their venom, and funnel web spiders thrive in captivity and are easy to "milk". It may be possible to target specific pests by engineering genes for the production of spider toxins into viruses that infect species such as cotton bollworms.[97]

The Ch'ol Maya use a beverage created from the tarantula species Brachypelma vagans for the treatment of a condition they term 'tarantula wind', the symptoms of which include chest pain, asthma and coughing.[98]

Possible medical uses for spider venoms are being investigated, for the treatment of cardiac arrhythmia,[99] Alzheimer's disease,[100] strokes,[101] and erectile dysfunction.[102] The peptide GsMtx-4, found in the venom of Brachypelma vagans, is being researched to determine whether or not it could effectively be used for the treatment of cardiac arrhythmia, muscular dystrophy or glioma.[98] Because spider silk is both light and very strong, attempts are being made to produce it in goats' milk and in the leaves of plants, by means of genetic engineering.[103][104]

Spiders can also be used as food. Cooked tarantula spiders are considered a delicacy in Cambodia,[105] and by the Piaroa Indians of southern Venezuela – provided the highly irritant hairs, the spiders' main defense system, are removed first.[106]

Arachnophobia

Arachnophobia is a specific phobia—it is the abnormal fear of spiders or anything reminiscent of spiders, such as webs or spider-like shapes. It is one of the most common specific phobias,[107][108] and some statistics show that 50% of women and 10% of men show symptoms.[109] It may be an exaggerated form of an instinctive response that helped early humans to survive,[110] or a cultural phenomenon that is most common in predominantly European societies.[111]

Spiders in culture

Arañamuseolarco
This Moche ceramic depicts a spider, and dates from around 300 CE.

Spiders have been the focus of stories and mythologies of various cultures for centuries.[112] Uttu, the ancient Sumerian goddess of weaving, was envisioned as a spider spinning her web.[113][114] According to her main myth, she resisted her father Enki's sexual advances by ensconcing herself in her web,[114] but let him in after he promised her fresh produce as a marriage gift,[114] thereby allowing him to intoxicate her with beer and rape her.[114] Enki's wife Ninhursag heard Uttu's screams and rescued her,[114] removing Enki's semen from her vagina and planting it in the ground to produce eight previously-nonexistent plants.[114] In a story told by the Roman poet Ovid in his Metamorphoses, Arachne was a Lydian girl who challenged the goddess Athena to a weaving contest.[115][116] Arachne won, but Athena destroyed her tapestry out of jealousy,[116][117] causing Arachne to hang herself.[116][117] In an act of mercy, Athena brought Arachne back to life as the first spider.[116][117] Stories about the trickster-spider Anansi are prominent in the folk traditions of the Asante people of Ghana.[118]

In some cultures, spiders have symbolized patience due to their hunting technique of setting webs and waiting for prey, as well as mischief and malice due to their venomous bites.[119] The Italian tarantella is a dance to rid the young woman of the lustful effects of a spider bite. Web-spinning also caused the association of the spider with creation myths, as they seem to have the ability to produce their own worlds.[120] Dreamcatchers are depictions of spiderwebs. The Moche people of ancient Peru worshipped nature.[121] They placed emphasis on animals and often depicted spiders in their art.[122]

See also

Footnotes

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Bibliography

  • Deeleman-Reinhold, Christa L. (2001). Forest Spiders of South East Asia: With a Revision of the Sac and Ground Spiders. Brill Publishers. ISBN 978-9004119598.
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Further reading

  • Bilger, Burkhard (5 March 2007). "Spider Woman". The New Yorker: 66–73.
  • Bristowe, W.S. (1976). The World of Spiders. Taplinger Publishing Company. ISBN 978-0-8008-8598-4. OCLC 256272177.
  • Crompton, John (1950). The Life of the Spider. New York: Mentor. OCLC 1979220.
  • Hillyard, Paul (1994). The Book of the Spider: From Arachnophobia to the Love of Spiders. New York: Random House. ISBN 978-0-679-40881-9. OCLC 35231232.
  • Kaston, B.J.; Kaston, Elizabeth (1953). How to Know the Spiders; Pictured-Keys for Determining the More Common Spiders, with Suggestions for Collecting and Studying Them (1st ed.). Dubuque, Iowa: W.C. Brown Company. OCLC 628203833.
  • Main, Barbara York (1975). Spiders. Sydney: Collins. ISBN 978-0-00-211443-1. OCLC 123151744.
  • Wise, David A. (1993). Spiders in Ecological Webs. Cambridge studies in ecology. Cambridge: Cambridge University Press. ISBN 978-0-521-32547-9. OCLC 25833874.

External links

Doctor Octopus

Doctor Octopus (Otto Octavius) is a fictional character appearing in American comic books published by Marvel Comics. A highly intelligent mad scientist, Doctor Octopus is typically portrayed as a stocky, myopic man who utilizes four powerful, mechanical appendages, and is a prominent enemy of the superhero Spider-Man.

The character has appeared in numerous Spider-Man animations and video games, and is portrayed by Alfred Molina in the 2004 film Spider-Man 2. In 2009, Doctor Octopus was ranked as IGN's 28th Greatest Comic Book Villain of All Time. His first brief appearance as the Superior Spider-Man was in Daredevil vol. 3 #21 (December 2012) and his first full appearance of the same character was in Avenging Spider-Man #15.1 (Dec. 2012). Comics journalist and historian Mike Conroy writes of the character: "Created by Stan Lee and artist Steve Ditko, Doc Ock, as he became known, has become one of the web slinger's most persistent and dangerous foes." IGN rated him as the greatest enemy of Spider-Man. Though historically portrayed as a supervillain, some depictions of him in the 2000s have indicated him to harbor more noble and honorable character traits, including those seen in the film Spider-Man 2, in the action-adventure video game Marvel's Spider-Man, and in the Superior Spider-Man comics series. In the mainstream comics universe, Octavius has been recently portrayed as struggling to redeem himself, as the antihero Superior Octopus.

Huntsman spider

Huntsman spiders, members of the family Sparassidae (formerly Heteropodidae), are known by this name because of their speed and mode of hunting. They also are called giant crab spiders because of their size and appearance. Larger species sometimes are referred to as wood spiders, because of their preference for woody places (forests, mine shafts, woodpiles, wooden shacks). In southern Africa the genus Palystes are known as rain spiders or lizard-eating spiders. Commonly they are confused with baboon spiders from the Mygalomorphae infraorder, which are not closely related.

More than a thousand Sparassidae species occur in most warm temperate to tropical regions of the world, including much of Australasia, Africa, Asia, the Mediterranean Basin, and the Americas.Several species of huntsman spider can use an unusual form of locomotion. The wheel spider (Carparachne aureoflava) from the Namib uses a cartwheeling motion, while Cebrennus rechenbergi uses a handspring motion.

Miles Morales

Miles Gonzalo Morales () is a fictional comic book superhero appearing in publications by the American publisher Marvel Comics, and one of the characters known as Spider-Man. The character was created in 2011 by writer Brian Michael Bendis and artist Sara Pichelli, with input by Marvel's then-editor-in-chief Axel Alonso.

Miles Morales first appeared in Ultimate Fallout #4 (August 2011), following the death of Peter Parker. An Afro-Latino teenager, Miles is the second Spider-Man to appear in Ultimate Marvel, an imprint with a separate continuity from the mainstream Marvel Universe. Although Morales featured in the Ultimate Comics: Spider-Man comic book series, he is not the lead character in the Ultimate Spider-Man animated TV series that debuted in April 2012 on Disney XD, but he was later added to the main cast in 2016, and is the main character in the 2018 feature film, Spider-Man: Into the Spider-Verse, which won the Academy Award for Best Animated Feature. After Marvel ended the Ultimate imprint in 2015, Miles was made a character in the main Marvel Universe, and began appearing in stories under the All-New, All-Different Marvel branding that debuted that same year.

Reaction to the character varied, with some, including Spider-Man's co-creator, Stan Lee, approving the creation of a positive role model for children of color, and others expressing displeasure at the replacement of Peter Parker, with some critics decrying it as a publicity stunt motivated by political correctness, a charge Alonso denied. Alexandra Petri of The Washington Post called for the character to be judged on the quality of its stories, which have garnered positive reviews.The character possesses powers similar to those of the original Spider-Man, which were derived from the bite of a spider genetically engineered by Spider-Man's nemesis Norman Osborn in an attempt to duplicate those abilities.

Mysterio

Mysterio is the name of several fictional supervillains appearing in American comic books published by Marvel Comics, commonly as enemies of Spider-Man. The first and most high-profile incarnation of Mysterio is Quentin Beck, although several other characters have since used the Mysterio alias.

The character has appeared in numerous Spider-Man cartoons and video games. In 2009, Mysterio was ranked as IGN's 85th Greatest Comic Book Villain of All Time. Mysterio will make his film debut in the 2019 film Spider-Man: Far From Home, portrayed by Jake Gyllenhaal.

Pholcidae

Pholcidae, commonly known as cellar spiders, daddy long-legs spider, granddaddy long-legs spider, carpenter spider, daddy long-legger, vibrating spider and skull spider, is a family of araneomorph spiders first described by Ludwig Carl Christian Koch in 1850. It contains over 1800 species divided in 94 genera.The common name "daddy long-legs" is the common name for several species, especially Pholcus phalangioides, but is als the common name for several other arthropod groups, including harvestmen, which are arachnids but not spiders, and crane flies.

Spider-Man

Spider-Man is a fictional superhero created by writer-editor Stan Lee and writer-artist Steve Ditko. He first appeared in the anthology comic book Amazing Fantasy #15 (August 1962) in the Silver Age of Comic Books. He appears in American comic books published by Marvel Comics, as well as in a number of movies, television shows, and video game adaptations set in the Marvel Universe. In the stories, Spider-Man is the alias of Peter Parker, an orphan raised by his Aunt May and Uncle Ben in New York City after his parents Richard and Mary Parker were killed in a plane crash. Lee and Ditko had the character deal with the struggles of adolescence and financial issues, and accompanied him with many supporting characters, such as J. Jonah Jameson, Flash Thompson, Harry Osborn, romantic interests Gwen Stacy and Mary Jane Watson, and foes such as Doctor Octopus, Green Goblin and Venom. His origin story has him acquiring spider-related abilities after a bite from a radioactive spider; these include clinging to surfaces, shooting spider-webs from wrist-mounted devices, and detecting danger with his "spider-sense".

When Spider-Man first appeared in the early 1960s, teenagers in superhero comic books were usually relegated to the role of sidekick to the protagonist. The Spider-Man series broke ground by featuring Peter Parker, a high school student from Queens behind Spider-Man's secret identity and with whose "self-obsessions with rejection, inadequacy, and loneliness" young readers could relate. While Spider-Man had all the makings of a sidekick, unlike previous teen heroes such as Bucky and Robin, Spider-Man had no superhero mentor like Captain America and Batman; he thus had to learn for himself that "with great power there must also come great responsibility"—a line included in a text box in the final panel of the first Spider-Man story but later retroactively attributed to his guardian, the late Uncle Ben.

Marvel has featured Spider-Man in several comic book series, the first and longest-lasting of which is The Amazing Spider-Man. Over the years, the Peter Parker character developed from a shy, nerdy New York City high school student to troubled but outgoing college student, to married high school teacher to, in the late 2000s, a single freelance photographer. In the 2010s, he joins the Avengers, Marvel's flagship superhero team. Spider-Man's nemesis Doctor Octopus also took on the identity for a story arc spanning 2012–2014, following a body swap plot in which Peter appears to die. Marvel has also published books featuring alternate versions of Spider-Man, including Spider-Man 2099, which features the adventures of Miguel O'Hara, the Spider-Man of the future; Ultimate Spider-Man, which features the adventures of a teenaged Peter Parker in an alternate universe; and Ultimate Comics Spider-Man, which depicts the teenager Miles Morales, who takes up the mantle of Spider-Man after Ultimate Peter Parker's supposed death. Miles is later brought into mainstream continuity, where he works alongside Peter.

Spider-Man is one of the most popular and commercially successful superheroes. As Marvel's flagship character and company mascot, he has appeared in countless forms of media, including several animated and live action television series, syndicated newspaper comic strips, and in a series of films. The character was first portrayed in live action by Danny Seagren in Spidey Super Stories, a The Electric Company skit which ran from 1974 to 1977. In films, Spider-Man has been portrayed by actors Tobey Maguire, Andrew Garfield, and Tom Holland. Reeve Carney starred as Spider-Man in the 2010 Broadway musical Spider-Man: Turn Off the Dark. Spider-Man has been well received as a superhero and comic book character, and he is often ranked as one of the most popular and iconic comic book characters of all time and one of the most popular characters in all fiction.

Spider-Man (2002 film)

Spider-Man is a 2002 American superhero film based on the Marvel Comics character of the same name. Directed by Sam Raimi from a screenplay by David Koepp, it is the first installment in the Spider-Man trilogy, and stars Tobey Maguire as the title character, alongside Willem Dafoe, Kirsten Dunst, James Franco, Cliff Robertson, Rosemary Harris, and J. K. Simmons. The film centers on an outcasted teen named Peter Parker, who develops spider-like superhuman abilities after being bitten by a genetically-altered spider. He is later driven to use his new abilities for a good purpose, as the vigilante Spider-Man, to atone for his uncle's murder.

After progress on the film stalled for nearly 25 years, it was licensed for a worldwide release by Columbia Pictures in 1999 after it acquired options from Metro-Goldwyn-Mayer on all previous scripts developed by Cannon Films, Carolco, and New Cannon. Exercising its option on just two elements from the multi-script acquisition (a different screenplay was written by James Cameron, Ted Newsom, John Brancato, Barney Cohen, and Joseph Goldman), Sony hired Koepp to create a working screenplay (credited as Cameron's), and Koepp received sole credit in final billing. Directors Roland Emmerich, Ang Lee, Chris Columbus, Jan de Bont, M. Night Shyamalan, Tony Scott, and David Fincher were considered to direct the project before Raimi was hired as director in 2000. The Koepp script was rewritten by Scott Rosenberg during pre-production and received a dialogue polish from Alvin Sargent during production. Filming took place in Los Angeles and New York City from January 8 to June 30, 2001. Sony Pictures Imageworks handled the film's visual effects.Spider-Man premiered at the Mann Village Theater on April 29, 2002, and was released in the United States four days later on May 3. It received generally favorable reviews from critics, who praised its action sequences, romantic moments, visual effects, direction and performances. The film became a financial success: it was the first film to reach $100 million in a single weekend, and became the most successful film based on a comic book. With a box office gross of over $821.7 million worldwide, it was the third highest-grossing film of 2002 and became the seventh highest-grossing film of all time. Spider-Man is credited for redefining the modern superhero genre, as well as the summer blockbuster. It was followed by the sequels Spider-Man 2 and Spider-Man 3 in 2004 and 2007, respectively.

Spider-Man (2018 video game)

Marvel's Spider-Man is a 2018 action-adventure game developed by Insomniac Games and published by Sony Interactive Entertainment. Based on the Marvel Comics superhero Spider-Man, it is inspired by the long-running comic book mythology and adaptations in other media. In the game's main storyline, the super-human crime lord Mr. Negative orchestrates a plot to seize control of New York City's criminal underworld. When Mr. Negative threatens to release a deadly virus, Spider-Man must confront him and protect the city while dealing with the personal problems of his civilian persona, Peter Parker.

Gameplay is presented from the third-person perspective with a primary focus on Spider-Man's traversal and combat abilities. Spider-Man can freely move around New York City, interacting with characters, undertaking missions, and unlocking new gadgets and suits by progressing through the main story or completing tasks. Outside the story, the player is able to complete side missions to unlock additional content and collectible items. Combat focuses on chaining attacks together, and using the environment and webs to incapacitate numerous foes while avoiding damage.

Development of Marvel's Spider-Man, the first licensed game by Insomniac in its then-22 year history, began in 2014 and took approximately four years. Marvel gave Insomniac the choice of using any character from their catalogue to work on; Spider-Man was chosen both for his appeal to the employees and the similarities in traversal gameplay to their previous game Sunset Overdrive (2014). The game design took inspiration from the history of Spider-Man across all media but both Marvel Comics and Insomniac wanted to tell an original story that was not linked to an existing property, creating a unique universe (known as Earth-1048) that has since appeared in novels, merchandise, movies, and comics.

Marvel's Spider-Man was released worldwide for the PlayStation 4 video game console on September 7, 2018. The game received praise for its narrative, characterization, combat, and web-swinging traversal mechanics, although some criticized its open-world design for lacking innovation. A number of reviewers called it one of the best superhero games ever made, some comparing it favorably with the Batman: Arkham series. Following its release, Marvel's Spider-Man became one of the fastest-selling games of the year, one of the best-selling PlayStation 4 games of all time, and the fastest-selling superhero game in the United States. Spider-Man was followed by a story-based, three-part downloadable content called Spider-Man: The City that Never Sleeps, which was released monthly from October that year, that takes place after the main game.

Spider-Man 2

Spider-Man 2 is a 2004 American superhero film directed by Sam Raimi and written by Alvin Sargent from a story by Alfred Gough, Miles Millar and Michael Chabon. A sequel to the 2002 film Spider-Man, it is the second installment in the Spider-Man trilogy based on the fictional Marvel Comics character of the same name. Tobey Maguire stars as Peter Parker / Spider-Man, alongside Kirsten Dunst, James Franco, Alfred Molina, Rosemary Harris, and Donna Murphy.

Set two years after the events of Spider-Man, the film finds Peter Parker struggling to manage both his personal life and his duties as Spider-Man, which affects his civilian life dramatically. Meanwhile, Dr. Otto Octavius becomes a diabolical villain after a failed experiment kills his wife and leaves him neurologically fused to mechanical tentacles. Spider-Man must stop him from successfully recreating the experiment, which threatens to destroy the city, while dealing with a subconscious desire to stop being Spider-Man that is stripping him of his powers.

Principal photography began in April 2003 in New York City and also took place in Los Angeles. Spider-Man 2 was released in both conventional and IMAX theaters on June 30, 2004 and grossed $783 million worldwide, becoming the third highest-grossing film of the year. It won the Academy Award for Best Visual Effects and was also nominated for Best Sound Mixing and Best Sound Editing; it also received five awards at the Saturn Awards, including Best Fantasy Film and Best Director for Raimi. It is considered as one of the most influential and best superhero films of all-time. Its success led to Spider-Man 3 (2007).

Spider-Man 3

Spider-Man 3 is a 2007 American superhero film based on the fictional Marvel Comics character Spider-Man. It was directed by Sam Raimi from a screenplay by Raimi, his older brother Ivan, and Alvin Sargent. It is the third and final installment in Raimi's original Spider-Man film trilogy, following Spider-Man (2002) and Spider-Man 2 (2004). The film stars Tobey Maguire as Peter Parker / Spider-Man, alongside Kirsten Dunst, James Franco, Thomas Haden Church, Topher Grace, Bryce Dallas Howard, Rosemary Harris, Cliff Robertson, J. K. Simmons, and James Cromwell. It is the highest-grossing Spider-Man film ever made. Following the events of Spider-Man 2, Peter Parker has finally preparing for his future Mary Jane Watson from her Broadway career. But, first, he comes to face his vengeful best friend Harry Osborn/New Green Goblin for his father's death, an escaped Flint Marko falls into a particle accelerator and becomes a shape shifting Sandman and an extraterrestrial symbiote that bonds with Peter, negatively influencing his behavior.

Development of Spider-Man 3 began immediately after the release of Spider-Man 2 for a 2007 release. During pre-production, Raimi originally wanted another villain to be included along with Sandman. At the request of producer Avi Arad, he added Venom, and the producers also requested the addition of Gwen Stacy. Principal photography for the film began in January 2006, and took place in Los Angeles and Cleveland before moving to New York City from May until July 2006. Additional pick-up shots were made after August and the film wrapped in October 2006. During post-production, Sony Pictures Imageworks created 900 visual effects shots. With an estimated production budget of $258 million, it was the most expensive film ever made at the time of its release.

Spider-Man 3 premiered on April 16, 2007 in Tokyo, and was released in the United States in both conventional and IMAX theaters on May 4, 2007. The film grossed $890.9 million worldwide, making it the most successful film of the trilogy and the third-highest of 2007. The film received mixed reviews from critics, who responded positively to the musical score, special effects, performances, and action scenes, while less so to aspects of the plot and the use of multiple villains, most notably Venom. A fourth film, titled Spider-Man 4, was set to be released on May 6, 2011 followed by a Venom spin off, but were cancelled due to Raimi’s withdrawal over creative differences with the writers and producers. The film series was rebooted twice, first with The Amazing Spider-Man by Marc Webb and later a new film series set within the Marvel Cinematic Universe directed by Jon Watts beginning with Spider-Man: Homecoming.

Spider-Man in film

The fictional character Spider-Man, a comic book superhero created by Stan Lee and Steve Ditko and featured in Marvel Comics publications, has currently appeared in ten live-action films since his inception, not including fan made shorts and guest appearances in other Marvel Cinematic Universe (MCU) films. Spider-Man is the alter-ego of Peter Parker, a talented young freelance photographer and aspiring scientist imbued with superhuman abilities after being bitten by a radioactive/genetically-altered spider.

The first live-action film based on Spider-Man was the unauthorized short Spider-Man by Donald F. Glut in 1969. This was followed by Spider-Man, an American made-for-television film that premiered on the CBS network in 1977. It starred Nicholas Hammond and was intended as a backdoor pilot for what became a weekly episodic TV series.

The rights to further films featuring the character were purchased in 1985, and moved through various production companies and studios before being secured by Sony Pictures Entertainment (Columbia Pictures) for $10 million (plus 5% of any movies' gross revenue and half the revenue from consumer products), who hired Sam Raimi to direct Spider-Man (2002), Spider-Man 2 (2004), and Spider-Man 3 (2007) starring Tobey Maguire. The first two films were met with positive reviews from critics, while the third film received a more mixed response. In 2010, Sony announced that the franchise would be rebooted. Marc Webb was hired to direct, with Andrew Garfield starring, and The Amazing Spider-Man (2012) was released to positive reviews. The Amazing Spider-Man 2 (2014) saw mixed reviews.

In February 2015, Disney, Marvel Studios and Sony announced a deal to share the Spider-Man film rights, leading to a new iteration of Spider-Man being introduced and integrated into the MCU. The deal allows Sony to distribute and have creative control over MCU films where Spider-Man is the main character, while Disney distributes the ones where he is not. Tom Holland portrays this younger version of Spider-Man, appearing in Captain America: Civil War (2016), Spider-Man: Homecoming (2017), Avengers: Infinity War (2018) and Avengers: Endgame (2019), as well as a sequel to Homecoming, Spider-Man: Far From Home (2019). All of Spider-Man's MCU appearances have received positive reviews thus far.

Plans for an animated Spider-Man film were officially announced by Sony in April 2015. Spider-Man: Into the Spider-Verse (2018) combines Sony Pictures Imageworks' computer animation pipeline with traditional hand-drawn comic book techniques, inspired by the work of Miles Morales's co-creator Sara Pichelli. Completing the animation required up to 140 animators, the largest crew ever used by Sony Pictures Animation for a film. Into the Spider-Verse received universal acclaim, winning the Academy Award for Best Animated Feature and becoming the highest-rated film in the Spider-Man franchise, surpassing Spider-Man 2.

Raimi's trilogy grossed $2.5 billion worldwide on a $597 million budget, while Webb's films grossed over $1.4 billion on a $480 million budget. Homecoming grossed over $880 million on a $175 million budget and Into the Spider-Verse has grossed over $375 million on a $90 million budget. The Spider-Man films have grossed over $5.2 billion collectively at the global box office.

The Amazing Spider-Man

The Amazing Spider-Man is an American comic book series published by Marvel Comics, featuring the fictional superhero Spider-Man as its main protagonist. Being in the mainstream continuity of the franchise, it began publication in 1963 as a monthly periodical and was published continuously, with a brief interruption in 1995, until its relaunch with a new numbering order in 1999. In 2003 the series reverted to the numbering order of the first volume. The title has occasionally been published biweekly, and was published three times a month from 2008 to 2010. A video game based on the comic book series was released in 2000 and a film named after the comic book series was released July 3, 2012.

After DC Comics' relaunch of Action Comics and Detective Comics with new #1 issues in 2011, it had been the highest-numbered American comic still in circulation until it was cancelled. The title ended its 50-year run as a continuously published comic with issue #700 in December 2012. It was replaced by The Superior Spider-Man as part of the Marvel NOW! relaunch of Marvel's comic lines.The title was relaunched in April 2014, starting fresh from issue #1, after the "Goblin Nation" story arc published in The Superior Spider-Man and Superior Spider-Man Team-Up. In late 2015, The Amazing Spider-Man was relaunched again with a new volume with issue #1 following the 2015 Secret Wars event.

The Amazing Spider-Man (2012 film)

The Amazing Spider-Man is a 2012 American superhero film based on the Marvel Comics character Spider-Man, and sharing the title of the character's longest-running comic book. It is the fourth theatrical Spider-Man film produced by Columbia Pictures and Marvel Entertainment, and a reboot of Sam Raimi's Spider-Man 2002–2007 trilogy preceding it.

The film was directed by Marc Webb. It was written by James Vanderbilt, Alvin Sargent and Steve Kloves, and it stars Andrew Garfield as Peter Parker / Spider-Man alongside Emma Stone, Rhys Ifans, Denis Leary, Campbell Scott, Embeth Davidtz, Irrfan Khan, Martin Sheen and Sally Field. The film tells the story of Peter Parker, an introverted teenager from New York City, who takes up the alias of a masked vigilante: Spider-Man, after being bitten by a genetically engineered spider, and gaining spider-like superhuman abilities as a result, in order to hunt down his adoptive father/uncle's murderer. Eventually, Parker is compelled to stop his father's former scientific partner: Dr. Curt Connors, one of OsCorp's top biological researchers, who has exposed himself to an experimental mutagen, which has hampered his sanity and imbued him with a monstrous reptilian alter-ego, from spreading a mutation serum to the city's human population.

Development of the film began with the cancellation of Spider-Man 4 in 2010, ending director Sam Raimi's Spider-Man film series that originally featured Tobey Maguire as the titular superhero. Columbia Pictures opted to reboot the franchise with the same production team along with Vanderbilt to stay on with writing the next Spider-Man film, while Sargent and Kloves helped with the script as well. During pre-production, the main characters were cast in 2010. New designs were introduced from the comics, such as artificial web-shooters. Using Red Digital Cinema Camera Company's RED Epic camera, principal photography started in December 2010 in Los Angeles before moving to New York City. The film entered post-production in April 2011. 3ality Technica provided 3D image processing, and Sony Pictures Imageworks handled CGI. This was also the final American film to be scored by James Horner and released during his lifetime, before his death in 2015 from an aircraft accident.

Sony Pictures Entertainment built a promotional website, releasing many previews and launched a viral marketing campaign, among other moves. Tie-ins included a video game by Beenox. The film premiered on June 30 in Tokyo, and was released in the United States on July 3, ten years after release of Spider-Man (2002), in 2D, 3D and IMAX 3D and released in home media in November 2012. The reboot received generally positive reviews, with critics mostly praising Andrew Garfield's performance, the visual style, James Horner's musical score, and the realistic portrayal of the title character, but criticized some underdeveloped story-lines, noting the film's deleted scenes, and the introduction of the Lizard as the villain for being too surreal for the film. The film was a box office success, grossing over $757 million worldwide, becoming the seventh highest-grossing film of 2012. A sequel, The Amazing Spider-Man 2, was released on May 2, 2014.

The Amazing Spider-Man 2

The Amazing Spider-Man 2 (internationally marketed as The Amazing Spider-Man 2: Rise of Electro) is a 2014 American superhero film featuring the Marvel Comics character Spider-Man. The film was directed by Marc Webb and produced by Avi Arad and Matt Tolmach. It is the fifth theatrical Spider-Man film produced by Columbia Pictures and Marvel Entertainment, and is the sequel to 2012's The Amazing Spider-Man. It is also the second and final film in The Amazing Spider-Man duology. The studio hired James Vanderbilt to write the screenplay and Alex Kurtzman and Roberto Orci to rewrite it. The film stars Andrew Garfield as Peter Parker / Spider-Man, alongside Emma Stone, Jamie Foxx, Dane DeHaan, Campbell Scott, Embeth Davidtz, Colm Feore, Paul Giamatti and Sally Field.

Development of The Amazing Spider-Man 2 began after the success of The Amazing Spider-Man. DeHaan, Giamatti, Jones, and Cooper were cast between December 2012 and February 2013. Filming took place in New York City from February to June 2013. The film was released in 2D, 3D, and IMAX 3D on May 2, 2014, in the United States with two international premieres being held between March 31 and April 10 of that year. It received mixed reviews from critics and audiences and grossed $709 million worldwide, making it the ninth-highest-grossing film of 2014 but the lowest-grossing Spider-Man film.

The Amazing Spider-Man 2 was originally envisioned as the beginning of a shared fictional universe, which would have continued with two sequels and several spin-offs, most notably films centered on Venom and the Sinister Six. Due to its performing below expectations, all subsequent installments were cancelled and a new iteration of the character, portrayed by Tom Holland in the Marvel Cinematic Universe, began with the 2016 film Captain America: Civil War.

Venom (Marvel Comics character)

Venom is a fictional character appearing in American comic books published by Marvel Comics, commonly in association with Spider-Man. The character is a sentient alien Symbiote with an amorphous, liquid-like form, who survives by bonding with a host, usually human. This dual-life form receives enhanced powers and usually refers to itself as "Venom". The Symbiote was originally introduced as a living alien costume in The Amazing Spider-Man #252 (May 1984), with a full first appearance as Venom in The Amazing Spider-Man #300 (May 1988).

The Venom Symbiote's first human host was Spider-Man, who eventually discovered its true nefarious nature and separated himself from the creature in The Amazing Spider-Man #258 (November 1984) — with a brief rejoining five months later in Web of Spider-Man #1. The Symbiote went on to merge with other hosts, most notably Eddie Brock, its second and most infamous host, with whom it first became Venom and one of Spider-Man's archenemies.Comics journalist and historian Mike Conroy writes of the character: "What started out as a replacement costume for Spider-Man turned into one of the Marvel web-slinger's greatest nightmares." Venom was ranked as the 22nd Greatest Comic Book Villain of All Time in IGN's list of the top 100 comic villains. IGN also ranked Mac Gargan's incarnation of Venom as #17 in their list of "The Top 50 Avengers", while the Flash Thompson incarnation was ranked as #27. The character was listed as #33 on Empire's 50 Greatest Comic Book Characters.

Wolf spider

Wolf spiders are members of the family Lycosidae, from the Ancient Greek word "λύκος" meaning "wolf". They are robust and agile hunters with excellent eyesight. They live mostly in solitude and hunt alone, and do not spin webs. Some are opportunistic hunters pouncing upon prey as they find it or even chasing it over short distances. Some wait for passing prey in or near the mouth of a burrow.

Wolf spiders resemble nursery web spiders (family Pisauridae), but wolf spiders carry their egg sacs by attaching them to their spinnerets. (the Pisauridae carry their egg sacs with their chelicerae and pedipalps). Two of the wolf spider's eight eyes are large and prominent, which distinguishes them from the nursery web spiders whose eyes are all of roughly equal size. This can also help distinguish them from grass spiders.

Extant Araneae families
Spiders
Arachnology
Taxonomy
Anatomy
Human interaction
Webs
Arachnida orders

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