I was asked this question again the other day and I finally found someone that I think has the best answer. I found this article “Why do scorpions glow inn the dark (and could their whole body be one big eye)? by Ed Yong 12/23/2011
But Douglas Gaffin from the University of Oklahoma has a more intriguing idea. He thinks that scorpions glow to convert the dim UV light from the moon and the stars into the color that they see best – blue-green.
In 2010, Carl Kloock found evidence for this idea. He overexposed scorpions to UV light to use up the fluorescing chemicals in their skin (which break down as they glow).
These photo’s are from a friend David, who by the way has a few around his home (actually he is pretty good at tracking them down).