Johnson jumper (Phidippus johnsoni)

Report and Photograph Courtesy of Cat T., San Isidro, Texas, 2 June 2007

Cat Wrote:

What kind of spider is this?  It was photographed June 2, 2007 in San Isidro, TX (Starr County).  This one was on a fence post eating a grasshopper.  I have other photos that are higher resolution (about 2mb in size).  I cropped and resized this one to insert into this email...

I first informed Cat this was a male redbacked jumping spider (Phidippus johnsoni).  However, the accepted common name for this species, as tabulated by the American Arachnological Society, is the Johnson jumper, and that is the name I will use for it forthwith.  This species will bite humans if given the opportunity, but the bite is generally not serious. I told Cat that it would help if she sent the higher resolution images. She did so, and selected portions of those images are provided below.  Note that this spider is about 1/2 inch long (approx. 11mm):

The carapace (the forward portion of the spider that includes the head and thorax, to which the eight legs are attached) is dark, mostly black. The abdomen is almost entirely red. Males of this species have black carapaces and red abdomens that are not otherwise marked except for three pairs of dark depressions (the third pair, nearest the posterior abdomen, is faintly visible in the above photo but does not show in the photo below). Most females have a broad median black marking, slightly wider than the lateral distance between each of the dorsal parallel depressions, that stretches from the junction of the abdomen and carapace, backward along the dorsum of the abdomen to just beyond the second set of parallel depressions.  Since that mark is absent in this specimen, it is most likely a male.

Another spider in this genus (Phidippus apacheanus), whose range is centered in the Rocky Mountains, is similar in appearance to P. johnsoni, but has a red carapace and abdomen.  P. apacheanus is smaller than P. johnsoni (only 0.4 inches, or 9mm, long).

Note that on Cat's specimen the dorsal abdomen sports three pale hairs on its dorsum, about halfway between the first and second pairs of parallel depressions.

The dark coloration of the carapace, and of the eyes, combined with the general hairy features of the face, obscure our view of the eyes on the frontal face of this specimen.  I tried to enhance the image to bring out the features of the eyes to no avail. The small posterior eyes are visible, and two tiny eyes between them and the larger eyes on the frontal face are faintly visible--not as eyes but as tiny spots in the darkness of the face--but the larger eyes on the frontal face cannot be seen at all.  Would a flash have helped? Possibly.  For those taking nature photos, even in bright sunlight, consider using a forced flash to enhance subtle anatomical features. Generally, the onboard flash on your camera does an excellent job, especially when the photo is taken within a few feet or inches of the subject.

Cat is an excellent photographer, and took great pains to include important parts of the spider for us to see. Note the whitish hairs on the forelegs, visible in the above photo, and that, in two of these photos a line of silk can be seen near the spider's body.  This is the safety dragline used to steady the spider as it manipulates its prey.

Cat's reply:

Thanks for the ID. I scoured the net for spiders with red abdomens and narrowed it down to Phidippus...but that was as far as I got.  Didn't know they bite...eeek! ...and to think I was playing cat and mouse with this one trying to get photographs.  It kept scurrying around the back of the fence post and I'd stick my hand through the panel to shoo it back around to the front.  

Attached four photos from the ranch in San Isidro, TX (Starr County).  Photo #a - shows the white on the forelegs and the other photos don't...if you zoom in on photo #k you can see some tiny white hairs on the red abdomen.  This spider seemed to follow my every move.  Had I known it was a jumping spider I probably wouldn't have ventured in close!   Am still trying to get used to my new toy.  A Sony DSC H9.  Have been using a Panasonic Lumix for a couple of years and decided to treat myself to a new camera - so I try to practice with it every time I drive out to the ranch on weekends.  I usually stick to photographing butterflies, moths, caterpillars and their eggs - but not much was flying that afternoon.  This splash of red on a distant fence post attracted my attention.  Glad I able to get a few photos of it...even if it scared me just as much as the local tarantulas.   Thanks again,   Cat T., Edinburg, TX