I'm generally pretty tough on photos myself, especially insect macros which have to be just about perfect as there is so much great competition, but I agree this one should probably have made it in. Perfect DOF, nice and sharp, nice background. What's not to like?
I like the colour too. It is slightly yellow but nothing unpleasant or unnatural, I can't believe that judge dinged you about it.
Before you get too pleased about my comments
I should also add that I don't agree that the judges need to know about the full sunlight and natural setting etc. On the whole it is my opinion that the photo is either good enough or it isn't, the difficult circumstances in which you took it don't matter. (There are exceptions to this of course, but they are few and far between and usually involve photos which can never be repeated: e.g. photos taken on the moon, some war photography, etc)