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Photo#321482
Crab Spider - Flower Spider - Misumenoides formosipes

Crab Spider - Flower Spider - Misumenoides formosipes
Baton Rouge - BREC Bluebonnet Swamp Nature Center, East Baton Rouge Parish, Louisiana, USA
August 17, 2009
Size: about 15 mm
Found down in the swamp.
On Pickerelweed.
Usually Pickerelweed grows standing in water.
It has been dry and the water level is low and this plant is currently on dry ground.

Body size about 15 mm.
"Wing span" about 30 mm.

I will add two tightly cropped views of the eyes.

I read "Misumena, Misumenoides, and Misumenops" in BugGuide - Forums - Articles.
But couldn't decide for sure.

Notice on the anterior (front) eyes are two different colors.
Both on this specimen and on many of those in the article.
The inside pair are red.
The outside pair are dark (black?).
I wonder if they see different wavelengths of light?

Images of this individual: tag all
Crab Spider - Flower Spider - Misumenoides formosipes Crab Spider - Flower Spider - Misumenoides formosipes Crab Spider - Flower Spider - Misumenoides formosipes Crab Spider - Flower Spider - Dinner Time - Misumenoides formosipes

Moved
Moved from ID Request.

Ridge across the face through the eyes
This is Misumenoides formosipes. Would it be possible to rotate the other two images 180 degrees? I had to turn my monitor upside down to view them!

 
Flipped images
Hope your monitor is not a CRT.
Quite a job to flip those.

Interesting from Info tab for these spiders:
"Can be either white or yellow. Most sources say this is a response to its surroundings, but I did find one claim that color depended on whether the egg was laid on a yellow or white-flowered plant."

Now about those red eyes.

 
The eyes
> Now about those red eyes

I have noticed this is other species of Thomisidae, especially Misumena vatia and some Xysticus sp. If you look closely at a live spider, preferrably through a stereo microscope, you will see movement within the anterior median eyes. The color shifts from reddish to darker, almost black. At times it seems like a dark half moon moves across the eye. I believe this may be the retina on the inside of the eye, swivelling in different directions. Movement of the retina has been observed in other spiders, such as in the PME of salticids, enabling the spider to see in different directions without moving its body.

Anyway, I'm not up on the inner details of the eyes in this spider, but I believe that is why you see the lighter color. I know these spiders do see movement fairly well - they will sometimes move under the flower and hide when you approach. I don't think they see as well as salticids, but when they swivel their retinas I believe they are surveying their surroundings to some extent. I'm sorry I can't point you to any papers on this subject.

If you have a microscope, or a good magnifying glass, this movement is worth looking at.

 
Thanks
Seems logical.
And fun to think about.

In case someone wonders, I did not use flash, so no red eye from flash.

I took quite a few pictures and most have red eye, only in the center pair of eyes.
The few that do not have red eye are tough to say for sure because they are blurry.
No sun to shine off retina.
No sun to give enough light to stop motion of camera and flower.

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