luminescent eyes - have you seen this

[mark_h]

I took this image this morning, it is a very small spider sitting in a web on a leaf. I know this is not the best shot but it shows the eyes, I did not use a flash and the sky was overcast. When I first focused on it the eyes did not shine but when I touched the leaf it arched it's thorax and the eyes lite up. The stayed illuminated for a few moments and the went out, touched the leaf and the same thing happened.
Has anyone else seen this and possible name of the spider

[Craig Gerard]

mark,

Well, I'm intrigued. Excellent observation!

Spooky spider. I'll be interested to hear what the entomologists have to say about your spider.

I did a Google search for battery-powered spiders, but only managed to find the following information in reference to Wolf spiders (but yours is a web weaving spider) - not sure of an ID.

Wolf spiders apparently have night-vision capabilities, something about a tapetum at the back of their eyes which reflects light and enhances vision (link to video below).

Your spider seems to have the ability to turn on the lights at it's own discretion, most likely, as some type of warning signal. If it is not using reflected light, then I would like to know the energy source. I wonder if it turns on the lights when prey is caught in its web in addition to when it is threatened.

Here is a video of a Wolf Spider and its headlights:
http://www.youtube.com/watch?v=0AbqrfC64YE

Craig

[realjax]

Amazing!

(do you happen to live close to a nuclear waste facility by any chance ? )

[Charles Krebs]

Pretty sure it's somewhat like the classic "red-eye" effect you get with people shots and flash. Even though there was no flash used, when the spiders eyes are positioned a certain way there is a bright or colored reflection off of internal parts. I've seen similar:
http://www.photomacrography.net/forum/v ... php?t=2928

[Harold Gough]

when I touched the leaf it arched it's thorax and the eyes lite up. The stayed illuminated for a few moments and the went out, touched the leaf and the same thing happened.

The arching would cause a change in the angle of the eyes until the spider relaxed again. You could check this by lowering (also possibly by raising) your viewing angle in that same lighting situation.

The lack of colour in the legs and, more relevant, the slightly plump appearance of the appendages, suggest that it is immature. I could be wrong about that.

Harold

[Craig Gerard]

The original image has been replaced

Notice the light in the water drops?

Craig

[mark_h]

I thought about Mr. Krebs suggestion of the "red eye" effect so I went out yesterday morning 2 hours earlier to re-shoot the spider. I changed my shooting angle I to eliminate the reflection. I assumed the source of the reflection was the glass of the lens or the sky. I got the same reflection of two eyes I got the day before (updated the new image on my computer because it was clearer, not realizing it would change the image here).

I moved and got this image with three reflections

lastly I took this image and I think it verifies Mr.Krebs suggestion,
there is reflection from two eyes and the third (on the right) is not reflection.

Thanks for the suggestions and comments, I wonder what it sees through those reflections?

[DaveW]

The dog picture in this link may explain it:-

http://www.rain.org/~mkummel/stumpers/20oct00a.html

I think like cats eyes in the dark when the spiders eyes were pointing at you they reflected the skylight. Not all creatures eyes produce the red eye effect when they reflect light.

http://www.bevhoward.com/spidereyes.htm

http://www.flickr.com/photos/opoterser/3634381424/

DaveW

[mark_h]

thanks Dave, I found from further reading that some spiders have elements in their upward projecting eyes that are highly reflective, the article suggested they may use these properties to fix their location.
Well it was a good learning experience, I have not gone out at night with a light but I sure plan to.