Today was able to play with this guy for 45min, tried several shoots and he always jumped to my flash diffuser. The photo above is 1/25s (for expose to the sky), he jumped before the flash (so this is a all natural light shoot).
The time to prepare a jump is less than 1/25s then, and there was enough time to capture few details of the face, but the image is predominantly exposed to sky.
The flash fired, but had little or no effect on the image (was a Yongnuo YN 560 manual flash)
Jumper spider "soul"
by Gustavo Mazzarollo
, on Flickr
This was the proposed photo.
A view of the vivid colors in the body
A closer view at the jumper face.