Bold Jumping Spider (Phidippus Audax)
Harker Heights, Texas 15 May 2007

Photographs by Bryan H.

Bryan, a soldier at Fort Hood, Texas, supplied me with photos of this bold jumping spider on May 15, taken at his residence in Harker Heights.  Phidippus audax is one of our most common jumping spiders and is the archetype for the genus Phidippus.

As the above photo, of the ventral surfaces of this spider, shows, it has a delicate set of markings on each side of the ventral abdomen.  The dorsal abdomen, portrayed below, has a number of white spots arrayed in a pattern around a large white triangular patch in the center.  The anterior margin of the abdomen is white. Notice that the anterior portion of the carapace sports conspicuous "eyebrow" tufts of hairs in two groups, one pointing straight up, the other pointing at approximately 45 degrees to the side.  These tufts, along with the pedipalps with swollen distal ends (seen in the photo above in front of the spider's face) mark this as a male.

As a member of the Salticidae Family, P. audax has eight eyes and is possessed of unusually sharp vision. This gives the spider important advantages for hunting prey.  The eyes are arranged with four large eyes on the frontal surface of the face, and four smaller eyes on the dorsal head.  Two of the eyes on the frontal face--the anterior median eyes--are of exceptional size, and seem to provide the spider's sharpest vision.  Their lenses are fixed, but the retinas are moveable.

When one looks into the two largest eyes of a live spider of this species, the color of the eye changes color as the retina is moved about, being darkest of all when the spider is looking directly at its observer. The eyes are dichromic (sensitive to two portions of the visual spectrum), and are specially sensitive to green and ultraviolet radiation. This helps explain why, for the male P. audax, the chelicerae are often iridescent green; that coloration is used by the male to attract the female of the species.

Jumping spiders are predatory carnivores that eat insects and other spiders.  As active insectivores, they are considered very beneficial.  They do not spin webs, but use their silk as safety lines when they jump, so that, if they miss their mark, they can climb back to the places from whence they leap and try again.

The Salticidae are well-known for biting humans.  While gardening, for example, one may easily become bitten as the result of disturbing the spider's territory.  The effect of the bite either goes unnoticed, or results in a small, localized swelling that lasts a few hours to a few days.

We thank Bryan and his fellow soldiers for their service to our country and to the cause of freedom and liberty everywhere.