I did think about cropping it further but I wanted to stick to the rule of thirds on this one. The butterfly is roughly top and bottom on the thirds lines. Also it would be hard to crop without loosing the the tip of the grass.
Really could be sharper. Did you use unsharp mask on this? It could use a crop since the butterfly is so small compared to the background. Also, it's right in the middle center, not at thirds. Thirds means 1/3 from the left or 1/3 from the right, or bottom, or top. It means it's ON the 1/3 line (not between two 1/3 lines). The shot still has potential if you try working on it some more.