Jumping spiders
Jumping spider- Paraphidippus aurantius Image:JumpingSpider.JPG
: Animalia : Arthropoda : Arachnida : Araneae : Salticidae
Genera
Bagheera Corythalia Eris Freya Ghelna Habronattus Hentzia Lyssomanes Maevia Marpissa Messua Metacyrba Naphrys Paramarpissa Paraphidippus Phidippus Portia Salticus Sarinda Sassacus Sitticus Synemosyna Thiodina Zygoballus and many others

The jumping spiders (Salticidae) comprise a family of spiders containing more than 4,000 species. The one pictured (Paraphidippus aurantius) is native to North Carolina and is about ¼ inch (.5 cm) long.

Jumping spiders work like technical climbers in the world of mountain climbing. When a jumping spider is moving from place to place, and especially just before it jumps from one place to another, it tethers a filament of silk to whatever it is standing on. Should it fall for one reason or another, it just reels itself back to the point it secured its "climbing rope."

Jumping spiders have very good vision centered in their anterior median eyes (AME). These eyes are able to create a focused image on the retina, which has four layers of receptor cells in it. Physiological experiments have shown that they may have up to four different kinds of receptor cell, with different absorption spectra , giving them the possibility of up to tetrachromatic color vision, with sensitivity extending into the ultra-violet range. Color discrimination has been demonstrated in behavioral experiments.

Jumping spiders capture their prey by jumping on it from several inches away, and they may jump from twig to twig or leaf to leaf. They can carry out complex manoeuvres such as detours around obstacles in order to reach their prey. Their eyesight is much better than that of other spiders and most, if not all, insects. Most other spiders will only eat prey that they have captured live because they are unable to see dead prey (some long-legged sac spiders, family Miturgidae, and anyphaenid sac spiders, family Anyphaenidae, are exceptions as they can recognize insect eggs as food). Jumping spiders, however, will eat flies that have been killed for them. In the picture you can see that this jumping spider is aware of the photographer.

Jumping spiders also utilize their vision in complex visual courtship displays. Males are often quite different in appearance than females and may have plumose hairs, colored or metallic hairs, front leg fringes, structures on other legs and other, often bizarre, modifications. These are used in visual courtship in which the colored or metallic parts of the body are displayed and complex sideling, vibrational or zigzag movements are performed in a courtship "dance." 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.

Some jumping spiders, like the one pictured above, are very shy. Others seem very friendly and will happily jump from fingertip to fingertip, or (be careful!) from fingertip to nose. Unlike almost all other spiders, they can quite easily climb on glass. They also use their silk to weave themselves little tent-like dwellings. The females protect their eggs in these dwellings.

Even though they can be quite friendly, the larger ones will bite to protect themselves if you squeeze them. While the bite of a larger jumping spider can be painful, only a few species seem to produce any other effects. Almost all spiders (except uloborid spiders) have venom, but the venom of most spiders is not worse than the venom of bees.

Jumping spiders live in a variety of habitats, including mountains (one species is reported to have been the spider collected at the highest elevation on the slopes of Mt. Everest), tropical forests, deserts, temperate forests, scrub lands, and even in the intertidal zone (in Malaysia). None are truly aquatic, however, and tropical forests harbor the most species.

Several species of jumping spiders appear to mimic ants, beetles, or pseudoscorpions. Others may appear to be parts of grass stems, bumps on twigs, bark, part of a rock or even part of a sand surface.

External links

• Jumping Spiders of the World
• Jumping Spiders of NW-Europe
• Jumping spiders of Australia

References

• Crompton, J. (1954). The Life of the Spider. Mentor.
• 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.
• Forster, L. M. 1982. Vision and prey-catching strategies in jumping spiders. American Scientist 70165-175.
• 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.
• Kaston, B. J. (1953). How to Know the Spiders, Dubuque, Iowa.
• Nakamura, T., & Yamashita, S. (2000). Learning and discrimination of colored papers in jumping spiders (Araneae, Salticidae). Journal of Comparative Physiology A, 186, 897-201.
• Richman, D. B., and R. R. Jackson. (1992). A review of the ethology of jumping spiders (Araneae, Salticidae). Bulletin of the British Arachnological Society, 933-37.