Jumping Spider - Phidippus princeps
Live female spider photographed at Winfield, Illinois.
Family Salticidae - Jumping Spiders
Spider Index | Spider Main | Orb Web | Cobweb
Custom Search

Jumping Spider - Phidippus princeps

This little gal in her retreat web was the first jumping spider I'd ever attempted to macro photograph. She was quite patient with me but steadfastly refused to come out and play.

Jumping Spider - Phidippus princeps

A different time I had the same problem. Great fun though, and very photogenic.

Jumping Spider - Phidippus princeps

Jumping spiders have excellent vision, among the highest acuity in invertebrates. The eight eyes are grouped four on the face (the two big anterior median eyes in the middle, and two smaller anterior lateral eyes to the side), and four on top of the carapace. The two large, forward-facing eyes (AME) are tubular behind the lens, with a well-developed musculature, unique to salticids, that supports and moves the retina - the opposite arrangement of our own eyes. [1]


Note: the function of the posterior medial eyes is unknown [2]

Spider musculature is also different from ours: in the spider, muscles operate from the inside to move external skeletal elements; our own skeletal muscles surround the elements they operate. But even these glaring differences are nothing compared to the jumping spider's brain and digestive system - their esophagus passes right through the brain, and one branch of the gut (analogous to our intestines) actually overlies the eyes and brain. [1]

Jumping spider's anatomical points of interest:
  • Esophagus passes straight through the brain
  • Portion of gut overlies the eyes and brain inside carapace
  • Heart extends from abdomen into cephalothorax
  • Leg muscles attached inside the carapace operate legs like marionette puppets
  • Jumping spider's brain volume to body size proportionate to human, but visual processing region is larger
  • Salticids move retinas inside the eyes to look in different directions, as the lenses are fixed in the carapace
References
  1. Bugguide.net, Phidippus princeps
  2. Jumping Spider Vision, David Edwin Hill, via Creative Commons Attribution 3.0 Unported
  3. Arthur V. Evans, National Wildlife Federation Field Guide to Insects and Spiders of North America
  4. Clark Kimberling, University of Evansville, "Thomas Say, Father of American Entomology"
Wondering how to get that bug identified? Please see the kind folks at Bugguide.net. (North America)
North American Insects & Spiders is dedicated to macro photography of live, wild organisms in situ.
Custom Search
Class Arachnida / Order Araneae: Spiders are the largest group of arachnids.  They are easily recognized by their eight legs, and there are few creatures great or small that elicit such irrational fear in mankind. The vast majority of spiders are completely harmless and offer beneficial services, chief of which is keeping the burgeoning insect population in check. I am continually amazed at the resourcefulness of these supremely successful predators. Spider Index | Spider Main
© Red Planet Inc.