Daring Jumping Spider - Phidippus audax
Also commonly called Bold jumping spider. Spider Family: Salticidae
Live jumping spiders photographed in the wild at Winfield, Illinois, USA.
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Bold jumping spider
Daring Jumping Spider, Phidippus audax

Jumping spiders have acute stereoscopic vision, thanks to their large, forward-facing eyes. But rather than moves the eye itself, as most animals do, the jumping spder moves the retina behind the eye. You can see the moveable retina in the photograph above. The iridescent green chelicerae are diagnostic of the genus Phidippus in the jumping spider family, Salticidae.

Jumping spiders do not build spider webs for trapping prey - they use them for hiding and laying eggs only. Prey is stalked and killed much like a cat stalks a bird. A spider silk lifeline is always at the ready; if threatened, these guys rapidly lower themselves into the underbrush. They also use the line to climb back into postion should a jump go awry and they miss their target.

Bold jumping spider

Phidippus audax is one of the most common jumping spiders in North America. It is commonly called the "bold" or "daring jumping spider." Most casual photographers capture only this species.

The iridescent green chelicerae (jaws with fangs, pronounced keh-lisseree) were a big surprise when I got these pictures home and put them on the big monitor - I had not noticed them while shooting. Now that I know what to look for, I've learned this spider uses them as a threat display; rapidly waving its palpi (the little "feelers" underneath the face) in front of them, creating a miniature light-show flashing green warning sign. I would like to think this is the species that bit Peter Parker (aka Spiderman).

The more I see and study these spiders, the more captivating and fascinating they become. It is apparent others feel the same way; there is no dearth of information on Salticids on the web. Here are some links explaining astounding features of these creatures: The Tree of Life Web Project has an excellent jumping off place. There are articles, pictures and diagrams covering anatomy, physiology, vision, even movies of them pouncing.

The Arachnology Homepage has an astounding array of informational spider links.

 

Bold jumping spider
A wary female watches me like a hawk.

Bold jumping spider
This large (10mm) female had taken up hunting amongst the prickly pear cactus at McAllister Park, San Antonio, Texas.

Jumping spiders are easily distinguished from other spiders by their four big eyes on the face and four smaller eyes on top of the head. Around the world there are probably more than 5000 species of jumping spiders. Jumping spiders are charming lil buggers that look up and watch you. Although a jumping spider can jump more than fifty times its body length, none of its legs has enlarged muscles. The power for jumping comes from a quick contraction of muscles in the front part of the body increasing the blood pressure, which causes the legs to extend rapidly much as the hydraulics in a low-rider car.

Their vision also allows communications by visual means, such as the elaborate courtship dances that males perform. Salticids are perhaps as old and diverse as mammals, though not many humans know their world. Many salticids are colorful, they take on a variety of body forms, and some have disguises, looking like ants and other organisms. The bright colors and elaborate forms of some jumping spider species are involved in courtship.

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