The color is very vibrant in this photo, which I'm personally a sucker for. I do wish for a little more DOF, so that the entire flower that the bee is on could be in focus. It meets the challenge criteria, though the aditional "stuff" in the picture dillutes from the point. Yes, it is a good example of the principle of the rule of thirds, but it doesn't really highlight it as some other entries have done.
Other than that, there's nothing I can complain about on this photo, and a lot to like. Very well done, espicially considering the level of cooperation you probably got from the model. :)
The foreground petels are much softer and more blurred than the ones behind the bee, (probably because you had to shoot so fast to catch this little guy) which hurts the image some. I like the colors and placement of the flower and bee in the image and the white borders adds a little extra touch to it.