Jumping spider

Jumping spiders Fossil range: Eocene[1] - present
An adult female Phidippus mystaceus jumping spider
Scientific classification
Kingdom:	Animalia
Phylum:	Arthropoda
Class:	Arachnida
Order:	Araneae
Section:	Entelegynae
Superfamily:	Salticoidea
Family:	Salticidae Blackwall, 1842
Subfamilies
Aelurillinae Agoriinae Amycinae Ballinae Dendryphantinae Euophryinae Hasariinae Heliophaninae Hisponinae Lyssomaninae Marpissinae Myrmarachninae Pelleninae Plexippinae Salticinae Spartaeinae Synagelinae Synemosyninae See List of Salticidae genera
Diversity
553 genera, 5025 species

The jumping spider family (Salticidae) contains more than 500 described genera and about 5,000 described species,^[2] making it the largest family of spiders with about 13% of all species.^[3] Jumping spiders have good vision and use it for hunting and navigating. They are capable of jumping from place to place, secured by a silk tether. Both their book lungs and the tracheal system are well-developed, as they depend on both systems (bimodal breathing).

Habitat

Jumping spiders live in a variety of habitats. Tropical forests harbor the most species, but they are also found in temperate forests, scrub lands, deserts, intertidal zones, and even mountains. Euophrys omnisuperstes is a species reported to have been collected at the highest elevation, on the slopes of Mount Everest.^[4]

Jumping spiders are generally recognized by their eye pattern.

Behavior

Jumping spiders are generally diurnal, active hunters. Their well-developed internal hydraulic system extends their limbs by altering the pressure of body fluid (blood) 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 body. When a jumping spider is moving from place to place, and especially just before it jumps, it tethers a filament of silk to whatever it is standing on. Should it fall for one reason or another, it climbs back up the silk tether.

Jumping spiders are scopula-bearing spiders, which means that they have a very interesting tarsal section. At the end of each leg they have hundreds of tiny hairs, which each then split into hundreds more tiny hairs, each tipped with an "end foot". These thousands of tiny feet allow them to climb up and across virtually any terrain. They can even climb up glass by gripping onto the tiny imperfections, usually an impossible task for any spider.

Jumping spiders are known for their curiosity. If approached by a human hand, instead of scuttling away to safety as most spiders do, the jumping spider will usually leap and turn to face the hand. Further approach may result in the spider jumping backwards while still eyeing the hand. The tiny creature will even raise its forelimbs and hold its ground. It may even jump on the hand. Because of this contrast to other arachnids, the jumping spider is regarded as inquisitive as it is seemingly interested in whatever approaches it.

This behavior can be explained by the jumping spider's reliance on vision. Unlike many spiders, which use their secondary eyes mainly for navigation, the jumping spider also uses its secondary eyes to detect nearby entities (many other spiders rely instead on hairs for proximity detection). Having ascertained the presence of a nearby entity, jumping spiders will turn to examine it with the more accurate anterior median eyes, with which they identify the interloper as prey, natural phenomenon, possible threat, or potential mate. This leads them to behave in a manner suggestive of curiosity: since they are highly visual creatures that use their anterior median eyes to assess objects of interest, they must, by necessity, bring anything of interest into their visual field.

Vision

The eyes of a female Clynotis severus

Jumping spiders have very good vision centered in their anterior median eyes (AME). Their eyes are able to create a focused image on the retina, which has up to four layers of receptor cells in it (Harland & Jackson, 2000). Physiological experiments have shown that they may have up to four different kinds of receptor cells, with different absorption spectra, giving them the possibility of up to tetrachromatic color vision, with sensitivity extending into the ultraviolet range. It seems that all salticids, regardless of whether they have two, three, or four kinds of color receptors, are highly sensitive to UV light (Peaslee & Wilson, 1989). Some species (for example, Cosmophasis umbratica) are highly dimorphic in the UV spectrum, suggesting a role in sexual signaling (Lim & Li, 2005). Color discrimination has been demonstrated in behavioral experiments.

The principal eyes have high resolution (11 min. visual angle) [1], but the field of vision is narrow, from 2 to 5 degrees.

Hunting

Jumping spiders are active hunters, which means that they do not rely on a web to catch their prey. Instead, these spiders stalk their prey. They use their superior eyesight to distinguish and track their intended meals, often for several inches. Then, they pounce, giving the insect little to no time to react before succumbing to the spider's venom.^[5]

Diet

Female jumping spider with fly prey

Although spiders are generally carnivorous, there are some jumping spiders which include nectar and pollen in their diet^[6] and one species, Bagheera kiplingi, which feeds primarily on plant matter.^[7] None are known to feed on seeds or fruit. Plants such as the partridge pea offer the jumping spiders nectar through extrafloral nectaries, and in return the spiders help to protect the plant by killing and eating pests.

Reproduction

Male and female Phidippus clarus mating

Jumping spiders use their vision in complex visual courtship displays. Males are often quite different in appearance than females and may have plumose hairs, colored or iridescent hairs, front leg fringes, structures on other legs, and other, often bizarre, modifications. These are used in visual courtship in which the colored or iridescent parts of the body are displayed and complex sideling, vibrational, or zigzag movements are performed in a courtship "dance". If the female is receptive to the male she will assume a passive, crouching position. In some species, the female may also vibrate her palps or abdomen. The male will then extend his front legs towards the female to touch her. If the female remains receptive, the male will climb on the female's back and inseminate her with his palps.^[8]

A 2008 study of the species Phintella vittatain in Current Biology suggests that female spiders react to the male reflecting ultraviolet B light before mating, a finding that challenges the previously held assumption that animals did not register ultraviolet B light.^[9] In recent years it has been discovered that many jumping spiders may have auditory signals as well, with amplified sounds produced by the males sounding like buzzes or drum rolls.^[10]

Taxonomy and systematics

The monophyly of the family Salticidae is well established through both phylogenetic and morphological analyses. There is, however, no consensus on what other group of spiders are most closely related to the jumping spiders. Suggested sister groups have included the oxyopids (lynx spiders), thomisids (crab spiders), clubionoids (sac spiders), and web building spiders.^[11]

Jumping spiders can be divided into three major lineages: the lyssomanines (subfamily Lyssomaninae), the spartaeines (subfamily Spartaeinae), and the salticoids (unranked clade Salticoida).^[11] Of these, Salticoida accounts for over 90% of all jumping spider species. Salticoida can be further divided into numerous groups including Amycoida, Astioida, Aelurilloida, Euophryinae, Heliophaninae, Marpissoida, and Plexippoida.^[11]

Fossils

Jumping spider in Baltic amber

Very few jumping spider fossils have been found. Of those that are known, all are from Cenozoic era amber. The oldest fossils are from Baltic amber dating to the Eocene epoch, specifically, 54 to 42 Ma (million years ago). Other fossil jumping spiders have been found in Chiapas amber and Dominican amber.^[1]

See also

• List of Salticidae genera - List of Salticidae species
• Spider taxonomy

Footnotes

References

• Kaston, B.J. (1953). How to Know the Spiders, Dubuque, Iowa.
• Crompton, J. (1954). The Life of the Spider. Mentor.
• Forster, L.M. (1982). Vision and prey-catching strategies in jumping spiders. American Scientist 70: 165-175.
• Jackson, R.R. (1982). The behavior of communicating in jumping spiders (Salticidae). In P. Witt and J. Rovner (eds).Spider Communication Mechanisms and Ecological Significance, p. 213-247. Princeton, New Jersey.
• Peaslee, A.G. & Wilson, G. (1989). Spectral sensitivity in jumping spiders (Araneae, Salticidae). Journal of Comparative Physiology A 164: 359-363.
• Richman, D.B. & Jackson, R.R. (1992). A review of the ethology of jumping spiders (Araneae, Salticidae). Bulletin of the British Arachnological Society, 933-37.
• Jackman, John A. (1997). A Field Guide to Spiders & Scorpions of Texas. Gulf Publishing Company. Houston, Texas. p. 127.
• Harland, D.P & Jackson, R.R. (2000). 'Eight-legged cats' and how they see - a review of recent research on jumping spiders (Araneae: Salticidae). Cimbebasia 16: 231-240 PDF
• Nakamura, T. & Yamashita, S. (2000). Learning and discrimination of colored papers in jumping spiders (Araneae, Salticidae). Journal of Comparative Physiology A 186: 897-201.
• Elias, D.O., Mason, A.C., Maddison, W.P. & Hoy, R.R. (2003). Seismic signals in a courting male jumping spider (Araneae: Salticidae). Journal of Experimental Biology 206: 4029-4039.
• Lim, M.L.M. & Li, D. (2005). Extreme ultraviolet sexual dimorphism in jumping spiders (Araneae: Salticidae). Biological Journal of the Linnean Society 89: 397-406. doi:10.1111/j.1095-8312.2006.00704.x
• Richman, D.B., Edwards, G.B. & Cutler, B. (2005). Salticidae. pp. 205–216 in D. Ubick, P. Paquin, P. E. Cushing, and V. Roth (eds.) Spiders of North America: an identification manual. American Arachnological Society.
• Wesołowska, W. & Haddad, Ch.R. (2009). Jumping spiders (Araneae: Salticidae) of the Ndumo Game Reserve, Maputaland, South Africa. African Invertebrates 50 (1): 13-103.[2]

External links

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

Jumping Spider Fact Sheet

• Global Species Database of Salticidae
• Video of a jumping spider's mating behavior
• World Spider Catalog
• Jumping Spiders of the World
• Jumping Spiders of NW-Europe
• Jumping spiders of Australia
• Jumping spiders of Wisconsin
• Movies of Habronattus courtship behavior
• Male jumping spider courtship dance with contact microphone picking up and amplifying sounds