
The Itsy-Bitsy Spider -- Jumping Spider in Templeton, California

by Darin Volpe
Title
The Itsy-Bitsy Spider -- Jumping Spider in Templeton, California
Artist
Darin Volpe
Medium
Photograph - Photography
Description
This tiny jumping spider is less than 1/4-inch in length. It belongs to the species Colonus hesperus, one of the over 5800 species of jumping spiders in the world.
Jumping spiders' vision is among the best of all arthropods Like most spiders, they have eight eyes. The large prominent eyes have very good vision. The are built like telescopic tubes with a corneal lens in the front and a second lens in the back. They are too close together to allow depth perception as we do, but they have developed a way to use image focus, or lack thereof, to measure distance. The retinas are in two layers, the image is focused on the rear layer, and by measuring the amount of defocus on the front layer the spider can determine distance. In addition to the large front eyes, they also have the smaller forward-facing eyes which are able to distinguish some detail and are spaced widely enough to provide stereoscopic vision. The other two pairs of eyes are essentially motion detectors, detecting light and dark. Their combination of eyes gives them excellent forward vision and motion detection in almost 360 degrees.
Uploaded
May 28th, 2017
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