Wednesday, September 3, 2008

Jumping Spider (Eris sp.)

Beautifully colored and boldly patterened like most jumping spiders. As evinced by the relatively small abdomen and large pedipalps this is a male.

At first I thought this might be Eris militaris, the Bronze Jumper. But E. militaris has a white marking on the head which this spider lacks. Nor does this specimen have the abdomonal markings of Eris flava. And spiders can vary quite a bit from one individual to the next, so I'm uncertain as to the species ...

Jumping spiders stalk and pounce their prey rather than snaring it in a web and rely on their excellent vision to hunt. Their large eyes, clearly visible even from a distance in the first image, provide the spider with excellent forward vision.

As seen in the following photos the eyes are strategically placed about and elevated above the cephalothorax.

A few more pictures from different angles ...

This is a good sized jumping spider, about a quarter of an inch long. This shot of the spider sitting on my finger gives an idea of its size. Jumping spiders are active creatures, constantly in motion, and this one was no exception, making it a difficult subject to photograph. It's tricky to keep the camera in focus and shoot with only one hand.

He made himself at home and didn't seem to feel uncomfortable moving around on my fingers and wrist. (I didn't place the spider on my hand, it jumped there of its own volition.) Nor did I feel uneasy ... the spider has no reason to bite me. I'm not its natural prey, nor did I make it feel threatened.

Although jumping spiders don't spin webs to catch their prey they do attach a line before a jump so they can find their way back if necessary. This one made a leap from my hand and ended up on the road ... and also managed to get slightly entangled in his own silk.