I see no meaningful difference between the 2 since the subject is treated identically in each case. The rocks around the edges add no value for me so if I had to choose one, I'd go with A. An alternative crop I would consider is one where the subject is in the bottom left of the frame (have the lower left corner somewhere around the end of the bug's body with the wings completely covering the bottom and left sides). Yes, you'd be chopping a lot of the subject out of the shot this way but I think you'd gain more than you'd lose.
I had a more aggressive crop in mind where the corner is at the base of the wings. This would result in some clipping of the wings along the bottom and left sides. This was based on the goals of getting the subject off-center and eliminating rocks. This new crop accomplishes both of those to a degree, so imo, its an improvement.
If I had to choose between the two original positionings I would definitely choose A, as in B there is a stick visible at the bottom-left corner (diagonal to the corner) which sticks out like a sore thumb; without that stick there would be other variables to consider, but considering that stick there just isn't any choice, I have to go with A.