Jumping spiders are a group of

spider Spiders (order Araneae) are air-breathing arthropods that have eight legs, chelicerae with fangs generally able to inject venom, and spinnerets that extrude silk. They are the largest order of arachnids and rank seventh in total species d ...

s that constitute the

family Family (from la, familia) is a group of people related either by consanguinity (by recognized birth) or affinity (by marriage or other relationship). The purpose of the family is to maintain the well-being of its members and of society. Idea ...

Salticidae. As of 2019, this family contained over 600 described genera and over 6,000 described

species In biology, a species is the basic unit of Taxonomy (biology), classification and a taxonomic rank of an organism, as well as a unit of biodiversity. A species is often defined as the largest group of organisms in which any two individuals of ...

, making it the largest family of

s at 13% of all species. Jumping spiders have some of the best vision among

arthropod Arthropods (, (gen. ποδός)) are invertebrate animals with an exoskeleton, a Segmentation (biology), segmented body, and paired jointed appendages. Arthropods form the phylum Arthropoda. They are distinguished by their jointed limbs and Arth ...

s and use it in courtship, hunting, and navigation. Although they normally move unobtrusively and fairly slowly, most species are capable of very agile jumps, notably when hunting, but sometimes in response to sudden threats or crossing long gaps. Both their

book lung A book lung is a type of respiration organ used for atmospheric gas exchange that is present in many arachnids, such as scorpions and spiders. Each of these organs is located inside an open ventral abdominal, air-filled cavity (atrium) and conn ...

s and tracheal system are well-developed, and they use both systems (bimodal breathing). Jumping spiders are generally recognized by their

eye Eyes are organs of the visual system. They provide living organisms with vision, the ability to receive and process visual detail, as well as enabling several photo response functions that are independent of vision. Eyes detect light and conv ...

pattern. All jumping spiders have four pairs of eyes, with the anterior median pair being particularly large.

Distinguishing characteristics

Jumping spiders are among the easiest to distinguish from similar spider families because of the shape of the

cephalothorax The cephalothorax, also called prosoma in some groups, is a tagma of various arthropods, comprising the head and the thorax fused together, as distinct from the abdomen behind. (The terms ''prosoma'' and ''opisthosoma'' are equivalent to ''ceph ...

and their eye patterns. The families closest to Salticidae in general appearance are the

Corinnidae Corinnidae is a family of araneomorph spiders, sometimes called corinnid sac spiders. The family, like other "clubionoid" families, has a confusing taxonomic history. Once it was a part of the large catch-all taxon Clubionidae, now very much sma ...

(distinguished also by prominent spines on the back four legs), the Oxyopidae (the lynx spiders, distinguished by very prominent spines on all legs), and the

Thomisidae The Thomisidae are a family of spiders, including about 170 genera and over 2,100 species. The common name crab spider is often linked to species in this family, but is also applied loosely to many other families of spiders. Many members of thi ...

(the crab spiders, distinguished by their front four legs, which are very long and powerful). None of these families, however, have eyes that resemble those of the Salticidae. Conversely, the legs of jumping spiders are not covered with any very prominent spines. Their front four legs generally are larger than the hind four, but not as dramatically so as those of the crab spiders, nor are they held in the outstretched-arms attitude characteristic of the Thomisidae. In spite of the length of their front legs, Salticidae depend on their rear legs for jumping. The generally larger front legs are used partly to assist in grasping prey, and in some species, the front legs and pedipalps are used in species-recognition signalling. The jumping spiders, unlike the other families, have faces that are roughly rectangular surfaces perpendicular to their direction of motion. In effect this means that their forward-looking, anterior eyes are on "flat faces", as shown in the photographs. Their eye pattern is the clearest single identifying characteristic. They have eight eyes, as illustrated. Most diagnostic are the front row of four eyes, in which the anterior median pair are more dramatically prominent than any other spider eyes apart from the posterior median eyes of the Deinopidae. There is, however, a radical functional difference between the major (AME) eyes of Salticidae and the major (PME) eyes of the Deinopidae; the large posterior eyes of Deinopidae are adapted mainly to vision in dim light, whereas the large anterior eyes of Salticidae are adapted to detailed, three-dimensional vision for purposes of estimating the range, direction, and nature of potential prey, permitting the spider to direct its attacking leaps with great precision. The anterior lateral eyes, though large, are smaller than the AME and provide a wider forward field of vision. The rear row of four eyes may be described as strongly bent, or as being rearranged into two rows, with two large posterior lateral eyes being the furthest back. They serve for lateral vision. The posterior median eyes also have been shifted out laterally, almost as far as the posterior lateral eyes. They are usually much smaller than the posterior lateral eyes and there is doubt about whether they are at all functional in many species. The body length of jumping spiders generally ranges from . The largest is '' Hyllus giganteus'', while other genera with relatively large species include '' Phidippus'', '' Philaeus'' and '' Plexippus''. In addition to using their

silk Silk is a natural protein fiber, some forms of which can be woven into textiles. The protein fiber of silk is composed mainly of fibroin and is produced by certain insect larvae to form cocoons. The best-known silk is obtained from the ...

for safety lines while jumping, they also build silken "pup tents", where they take shelter from bad weather and sleep at night. They molt in these shelters, build and store egg cases in them, and also spend the winter in them.

Habitat

Jumping spiders live in a variety of habitats.

Tropical forest Tropical forests (a.k.a. jungle) are forested landscapes in tropical regions: ''i.e.'' land areas approximately bounded by the tropic of Cancer and Capricorn, but possibly affected by other factors such as prevailing winds. Some tropical fo ...

s harbor the most species, but they are also found in temperate forests, scrubland, deserts,

intertidal zone The intertidal zone, also known as the foreshore, is the area above water level at low tide and underwater at high tide (in other words, the area within the tidal range). This area can include several types of habitats with various species ...

s, and mountainous regions. '' Euophrys omnisuperstes'' is the species reported to have been collected at the highest elevation, on the slopes of

Mount Everest Mount Everest (; Tibetan: ''Chomolungma'' ; ) is Earth's highest mountain above sea level, located in the Mahalangur Himal sub-range of the Himalayas. The China–Nepal border runs across its summit point. Its elevation (snow ...

Vision

Jumping spiders have four pairs of eyes; three secondary pairs that are fixed and a principal pair that is movable. The posterior median eyes (PMEs) are vestigial in many species, but in some primitive subfamilies, they are comparable in size with the other secondary eyes and help to detect motion. While unable to form images, the reduced pair of eyes is thought to have a role similar to that of insect ocelli by receiving light from the sky. The photoreceptors in the other secondary pairs are almost exclusively green-sensitive, but the PMEs have two visual

opsin Animal opsins are G-protein-coupled receptors and a group of proteins made light-sensitive via a chromophore, typically retinal. When bound to retinal, opsins become Retinylidene proteins, but are usually still called opsins regardless. Most pro ...

s different from those in all the other eyes, sensitive to blue and UV light. The posterior lateral eyes (PLEs) are wide-angle motion detectors that sense motions from the side and behind. Combined with the other eyes, PLEs give the spider a near 360° view of the world. The anterior lateral eyes (ALEs) have the best visual acuity of the secondary eyes. They are able to distinguish some details, as well, and without them, no "looming response" can be triggered by motion. Even with all the other pairs covered, jumping spiders in a study could still detect, stalk, and attack flies, using their ALEs only, which are also sufficiently widely spaced to provide stereoscopic vision. The anterior median eyes (AMEs) have very good vision. This pair of eyes is built like a telescopic tube with a corneal lens in the front and a second lens in the back that focus images onto a four-layered retina, a narrow, boomerang-shaped strip oriented vertically. Physiological experiments have shown they may have up to four different kinds of receptor cells, with different absorption spectra, giving them the possibility of

tetrachromatic Tetrachromacy (from Greek ''tetra'', meaning "four" and ''chromo'', meaning "color") is the condition of possessing four independent channels for conveying color information, or possessing four types of cone cell in the eye. Organisms with tetr ...

color vision Color vision, a feature of visual perception, is an ability to perceive differences between light composed of different wavelengths (i.e., different spectral power distributions) independently of light intensity. Color perception is a part of ...

, with sensitivity extending into the

ultraviolet Ultraviolet (UV) is a form of electromagnetic radiation with wavelength from 10 nm (with a corresponding frequency around 30 PHz) to 400 nm (750 THz), shorter than that of visible light, but longer than X-rays. UV radiati ...

(UV) range. As the eyes are too close together to allow

depth perception Depth perception is the ability to perceive distance to objects in the world using the visual system and visual perception. It is a major factor in perceiving the world in three dimensions. Depth perception happens primarily due to stereopsi ...

, and the animals do not make use of motion parallax, they have evolved a method called image defocus, instead. Of the four photoreceptor layers in the retina, the two closest to the surface contain a UV-sensitive opsin (visual pigment), while the two deepest contain a green-sensitive opsin. The incoming green light is only focused on the deepest layer, while the other one receives defocused or fuzzy images. By measuring the amount of defocus from the fuzzy layer, calculating the distance to the objects in front of them is possible. In addition to receptor cells, red filters also have been detected, located in front of the cells that normally register green light. All salticids, regardless of whether they have two, three, or four kinds of color receptors, seemingly are highly sensitive to UV light. Some species (for example, '' Cosmophasis umbratica'') are highly dimorphic in the UV spectrum, suggesting a role in sexual signaling. Color discrimination has been demonstrated in behavioral experiments. The principal, AMEs have high resolution (11 min

visual angle Visual angle is the angle a viewed object subtends at the eye, usually stated in degrees of arc. It also is called the object's angular size. The diagram on the right shows an observer's eye looking at a frontal extent (the vertical arrow) t ...

), but the field of vision is narrow, from 2 to 5°. The central region of the retina, where acuity is highest, is no more than six or seven receptor rows wide. However, the eye can scan objects off the direct axis of vision. As the lens is attached to the carapace, the eye's scanning movements are restricted to its retina through a complicated pattern of translations and rotations. This dynamic adjustment is a means of compensation for the narrowness of the static field of vision. It is analogous to the way most

primate Primates are a diverse order (biology), order of mammals. They are divided into the Strepsirrhini, strepsirrhines, which include the lemurs, galagos, and lorisids, and the Haplorhini, haplorhines, which include the Tarsiiformes, tarsiers and ...

s move their eyes to focus images of interest onto their fovea centralis. Such movements within the jumping spider's eyes are visible from outside when the attention of the spider is directed to various targets.

Behavior

Jumping spiders are generally diurnal, active hunters. Their well-developed internal hydraulic system extends their limbs by altering the pressure of their body fluid ( hemolymph) within them. This enables the spiders to jump without having large muscular legs like a grasshopper. Most jumping spiders can jump several times the length of their bodies. When a jumping spider moves from place to place, and especially just before it jumps, it tethers a filament of

(or 'dragline') to whatever it is standing on to protect itself if the jump should fail. Should it fall, for example if the prey shakes it off, it climbs back up the silk tether. Some species, such as ''Portia'', actually let themselves down to attack prey such as a web spider apparently secure in the middle of its web. Like many other spiders that leave practically continuous silk trails, jumping spiders impregnate the silk line with pheromones that play a role in social and reproductive communication, and possibly in navigation. Certain species of jumping spiders have been shown by experiment to be capable of learning, recognizing, and remembering colors, and adapting their hunting behavior accordingly.

Hunting

The hunting behaviour of the Salticidae is confusingly varied compared to that of most spiders in other families. Salticids hunt diurnally as a rule, which is consistent with their highly developed visual system. When it detects potential prey, a jumping spider typically begins orienting itself by swivelling its

to bring the AMEs to bear. It then moves its

abdomen The abdomen (colloquially called the belly, tummy, midriff, tucky or stomach) is the part of the body between the thorax (chest) and pelvis, in humans and in other vertebrates. The abdomen is the front part of the abdominal segment of the tors ...

into line with its cephalothorax. After that, it might spend some time inspecting the object of its attention and determining whether a camouflaged or doubtful item of prey is promising, before it starts to stalk slowly forward. When close enough, the spider pauses to attach a dragline, then springs onto the prey. Many variations on the theme and many surprising aspects exist. For one, salticids do not necessarily follow a straight path in approaching prey. They may follow a circuitous course, sometimes even a course that takes the hunter through regions from which the prey is not visible. Such complex adaptive behaviour is hard to reconcile with an organism that has such a tiny brain, but some jumping spiders, in particular some species of ''Portia'', can negotiate long detours from one bush down to the ground, then up the stem of another bush to capture a prey item on a particular leaf. Such behaviour still is the subject of research. Some salticid species are continually on the move, stopping periodically to look around for prey, which they then stalk immediately. Others spend more time scanning their surroundings from one position, actively stalking any prey they detect. Members of the genus ''Phaeacius'' take that strategy to extremes; they sit on a tree trunk, facing downwards and rarely do any stalking, but simply lunge down on any prey items that pass close before them. Some Salticidae specialise in particular classes of prey, such as ants. Most spiders, including most salticids, avoid worker ants, but several species not only eat them as a primary item in their diets, but also employ specialised attack techniques; ''

Anasaitis canosa ''Anasaitis canosa'', previously of the genus '' Corythalia'', is a small jumping spider that can typically be found atop leaf-litter or man-made structures such as fences and exterior walls. This species is more commonly known as the twin-flagge ...

'', for example, circles around to the front of the ant and grabs it over the back of its head. Such myrmecophagous species, however, do not necessarily refuse other prey items, and routinely catch flies and similar prey in the usual salticid fashion, without the special precautions they apply in hunting dangerous prey such as ants. Ants offer the advantages of being plentiful prey items for which little competition from other predators occurs, but catching less hazardous prey when it presents itself remains profitable. Some of the most surprising hunting behaviours occur among the araneophagous Salticidae, and vary greatly in method. Many of the spider-hunting species quite commonly attack other spiders, whether fellow salticids or not, in the same way as any other prey, but some kinds resort to web invasion; nonspecialists such as '' Phidippus audax'' sometimes attack prey ensnared in webs, basically in acts of

kleptoparasitism Kleptoparasitism (etymologically, parasitism by theft) is a form of feeding in which one animal deliberately takes food from another. The strategy is evolutionarily stable when stealing is less costly than direct feeding, which can mean when fo ...

; sometimes they leap onto and eat the web occupant itself, or simply walk over the web for that purpose. Salticidae in the genera '' Brettus'', '' Cyrba'', '' Gelotia'', and ''

Portia Portia may refer to: Biology * ''Portia'' (spider), a genus of jumping spiders *'' Anaea troglodyta'' or Portia, a brush-footed butterfly *Portia tree, a plant native to Polynesia Medication A form of birth control made of ethinylestradiol/lev ...

'' display more advanced web-invasion behavior. They slowly advance onto the web and vibrate the silk with their pedipalps and legs. In this respect, their behaviour resembles that of the Mimetidae, probably the most specialised of the araneophagous spider families. If the web occupant approaches in the manner appropriate to dealing with ensnared prey, the predator attacks. The foregoing examples present the Salticidae as textbook examples of active hunters; they would hardly seem likely to build webs other than those used in reproductive activities, and in fact, most species really do not build webs to catch prey. However, exceptions occur, though even those that do build capture webs generally also go hunting like other salticids. Some ''Portia'' species, for example, spin capture webs that are functional, though not as impressive as some orb webs of the Araneidae; ''Portia'' webs are of an unusual funnel shape and apparently adapted to the capture of other spiders. '' Spartaeus'' species, though, largely capture moths in their webs. In their review of the ethology of the Salticidae, Richman and Jackson speculate on whether such web building is a relic of the evolution of this family from web-building ancestors. In hunting, the Salticidae also use their silk as a tether to enable them to reach prey that otherwise would be inaccessible. For example, by advancing towards the prey to less than the jumping distance, then retreating and leaping in an arc at the end of the tether line, many species can leap onto prey on vertical or even on inverted surfaces, which of course would not be possible without such a tether. Having made contact with the prey, hunting Salticidae administer a bite to inject rapid-acting venom that gives the victim little time to react. In this respect, they resemble the Mimetidae and Thomisidae, families that ambush prey that often are larger than the predator, and they do so without securing the victim with silk; they accordingly must immobilise it immediately and their venom is adapted accordingly.

Diet

Although jumping spiders are generally

carnivorous A carnivore , or meat-eater (Latin, ''caro'', genitive ''carnis'', meaning meat or "flesh" and ''vorare'' meaning "to devour"), is an animal or plant whose food and energy requirements derive from animal tissues (mainly muscle, fat and other ...

, many species have been known to include nectar in their diets, and one species, '' Bagheera kiplingi'', feeds primarily on plant matter. None are known to feed on seeds or fruit. Extrafloral nectaries on plants, such as ''

Chamaecrista fasciculata ''Chamaecrista fasciculata'', the partridge pea, is a species of legume native to most of the eastern United States. It is an annual which grows to approximately 0.5 meters tall. It has bright yellow flowers from early summer until first frost, ...

'' (partridge pea), provide jumping spiders with nectar; the plant benefits accordingly when the spiders prey on whatever pests they find. The female of the

Southeast Asia Southeast Asia, also spelled South East Asia and South-East Asia, and also known as Southeastern Asia, South-eastern Asia or SEA, is the geographical United Nations geoscheme for Asia#South-eastern Asia, south-eastern region of Asia, consistin ...

n species '' Toxeus magnus'' feeds its offspring with a milky, nutritious fluid for the first 40 days of their lives.

Reproduction

Courtship and mating behavior

Jumping spiders conduct complex, visual courtship displays using both movements and physical bodily attributes. Unlike females, males possess plumose hairs, colored or iridescent hairs (particularly pronounced in the peacock spiders), front leg fringes, structures on other legs, and other, often bizarre, modifications. These characteristics are used in a courtship "dance" in which the colored or iridescent parts of the body are displayed. In addition to the display of colors, jumping spiders perform complex sliding, vibrational, or zigzag movements to attract females. Many males have auditory signals, as well. These amplified sounds presented to the females resemble buzzes or drum rolls. Species vary greatly in visual and vibratory components of courtship. Many species have patches of UV reflectance, which are exhibited in mature males.(Lim, Matthew L. M., and Daiqin Li. "Courtship and Male-Male Agonistic Behaviour of Comsophasis Umbratica Simon, an Ornate Jumping Spider (Araneae: Salticidae)." The Raffles Bulletin of Zoology (2004): 52(2): 435-448. National University of Singapore. Web. 20 September 2015.) This visual component is used by some female jumping spiders for mate choice.Bulbert, Matthew W., James C. O’Hanlon, Shane Zappettini, Shichang Zhang, and Daiqin Li. "Sexually Selected UV Signals in the Tropical Ornate Jumping Spider, ''Cosmophasis umbratica'', May Incur Costs from Predation." Ecology and Evolution (2015): 5(4): 914-920. John Wiley & Sons Ltd. Web. 20 September 2015. If receptive to the male, the female assumes a passive, crouching position. In some species, the female may also vibrate her palps or abdomen. The male then extends his front legs towards the female to touch her. If the female remains receptive, the male climbs on her back and inseminates her with his palps.

Consequences of sexual dimorphism

Maintaining colorful ornamentation may seem strictly beneficial to sexual selection, yet costs to maintain such distinguishing characteristics occur. While colorful or UV-reflecting individuals may attract more female spiders, it can also increase the risk of predation.

Taxonomy

The

monophyly In cladistics for a group of organisms, monophyly is the condition of being a clade—that is, a group of taxa composed only of a common ancestor (or more precisely an ancestral population) and all of its lineal descendants. Monophyletic gr ...

of the family Salticidae is well established through both

phylogenetic In biology, phylogenetics (; from Greek φυλή/ φῦλον [] "tribe, clan, race", and wikt:γενετικός, γενετικός [] "origin, source, birth") is the study of the evolutionary history and relationships among or within groups o ...

and morphological analyses. The

sister group In phylogenetics, a sister group or sister taxon, also called an adelphotaxon, comprises the closest relative(s) of another given unit in an evolutionary tree. Definition The expression is most easily illustrated by a cladogram: Taxon A and ...

to Salticidae is the family Philodromidae.

Synapomorphies In phylogenetics, an apomorphy (or derived trait) is a novel character or character state that has evolved from its ancestral form (or plesiomorphy). A synapomorphy is an apomorphy shared by two or more taxa and is therefore hypothesized to hav ...

of the two families include loss of cylindrical gland spigots and loss of tapeta in the indirect eyes. A 2015 revision of the Salticidae family divided it into seven subfamilies: *

Onomastinae ''Onomastus'' is a genus of Asian jumping spiders (family Salticidae) that was first described by Eugène Louis Simon in 1900. It is the only genus in the subfamily Onomastinae. Description ''Onomastus'' species are delicate, translucent spiders ...

Maddison, 2015 – 1 extant genus *

Asemoneinae Asemoneinae is a subfamily of jumping spiders (family Salticidae). It was created in 2015 by Wayne Maddison. Most species are found in Africa or Asia. The subfamily initially had five genera, but '' Hindumanes'' was later transferred to the subf ...

Maddison, 2015 – 4 extant genera (''

Hindumanes ''Hindumanes'' is a genus of jumping spiders (family Salticidae) found in India. , two species have been described: *''Hindumanes karnatakaensis'' (Tikader & Biswas, 1978) *''Hindumanes wayanadensis ''Hindumanes'' is a genus of jumping spider ...

'', originally placed here, was moved to Lyssomaninae) *

Lyssomaninae Lyssomaninae is a subfamily of jumping spiders. It includes four genera, three from the New World. Description Members of the subfamily Lyssomaninae are mostly green or yellow, and have long legs compared to other salticids. The anterior later ...

Blackwall, 1877 – 3 extant genera (including ''Hindumanes'') *

Spartaeinae The Spartaeinae are a subfamily of the spider family Salticidae (jumping spiders). The subfamily was established by Fred R. Wanless in 1984 to include the groups Boetheae, Cocaleae, Lineae, Codeteae and Cyrbeae, which in turn were defined by Eu ...

Wanless, 1984 – 29 extant genera in 3 tribes * Eupoinae Maddison, 2015 – 3 extant genera *

Hisponinae Hisponinae is a subfamily of jumping spiders (family Salticidae). The subfamily has six known extant genera and three extinct genera. Description Members of the subfamily Hisponinae have a distinctive constriction or furrow in the carapace just ...

Simon, 1901 – 9 extant genera * Salticinae Blackwall, 1841 – about 540 extant genera in 27 tribes The Salticinae subfamily is the most diverse, comprising over 90% of the known species of jumping spiders.

Models for mimicry

Some small insects are thought to have evolved an appearance or behavioural traits that resemble those of jumping spiders and this is suspected to prevent their predation, specifically from jumping spiders. Some examples appear to be provided by patterns on the wings of some

tephritid The Tephritidae are one of two fly families referred to as fruit flies, the other family being the Drosophilidae. The family Tephritidae does not include the biological model organisms of the genus ''Drosophila'' (in the family Drosophilidae), ...

flies, the nymph of a fulgorid and possibly some moths.

Fossils

Very few jumping spider

fossil A fossil (from Classical Latin , ) is any preserved remains, impression, or trace of any once-living thing from a past geological age. Examples include bones, shells, exoskeletons, stone imprints of animals or microbes, objects preserved ...

s have been found. Of those known, all are from Cenozoic era

amber Amber is fossilized tree resin that has been appreciated for its color and natural beauty since Neolithic times. Much valued from antiquity to the present as a gemstone, amber is made into a variety of decorative objects."Amber" (2004). In M ...

. The oldest fossils are from Baltic amber dating to the

Eocene The Eocene ( ) Epoch is a geological epoch that lasted from about 56 to 33.9 million years ago (mya). It is the second epoch of the Paleogene Period in the modern Cenozoic Era. The name ''Eocene'' comes from the Ancient Greek (''ēṓs'', " ...

epoch, specifically, 54 to 42 million years ago. Other fossil jumping spiders have been preserved within Chiapas amber and Dominican amber.

References

External links

Asian jumping spiders and photo references

Comprehensive resource on the morphology and taxonomy of jumping spiders (Salticidae): www.jumping-spiders.com

Global Species Database of Salticidae

Video of a jumping spider's mating behavior

World Spider Catalog

American Jumping Spiders – 70 Species Videos (includes introduction to salticids, predation, mating, and other behaviors)

Movies of ''Habronattus'' courtship behavior

The Australian Faunal Directory taxonomic classification of Australian salticids
{{Taxonbar, from=Q11687 * Extant Eocene first appearances