That's funny 'cause to me he is adorable!! Very cute and furry like a lil' teddy bear.
It's not "Glowing", just its skin is reacting to the exposure. The white of the skin gives a glowing effect under some exposures conditions....
Well to tell you the truth I am not sure, but they don't "glow in the dark".
I have noticed on different spiders different apendages and body segments "glow" differently...
Weird, I am still trying to figure it out myself.