Nice close-up of this species Ian. The always seem like they have such a big eye. On my calibrated display the image looks quite dark. If I bump up the brightness on my display to maximum the image seems OK so maybe your work monitor is set quite bright? You may want to try to brighten it up without affecting the whites.
Love the moment in nature feeling here and what about those legs!! I would consider an adjusted crop to clean up the LLHC dark spot bottom edge. Nice low angle and and regarding John's comments check the histogram was it bunched on the left and was there data in a five stops. According to my calculations 1/400 at f5.6 is close to the sunny 16 rule - hence exposure techs are pretty solid.