Compositionally, I think you have the potential for a very strong photo. You have cut the very tips of the petals off, though, and that, I think, weakens the composition somewhat. I think a tighter crop, eliminating much of the 'brown' would really cause the viewer to focus more on the bee and yellow parts of the flower. Obviously, you would not be able to eliminate all of the background, but letting some go, especially in the lower right hand corner, would be beneficial I think. You would also have to work it a bit to make sure the bee did not end up centered in the composition. Though that works sometimes, I think in a shot like this, it would be static feeling, and you would lose a lot of the "motion" that a picture of a bee implies.
Technically, the flower seems to be right on the edge of being blown out. Looking at your settings, I would recommend a slightly slower shutter speed. That would help to "richen" the colors present, and eliminate some of the brightness that is almost blown out. Also, it looks almost as if it were shot in direct sunlight. Obviously, you couldn't contract the bee to come back at a better time, so it might have been helpful to have someone hold something (even themselves) to cast a shadow over the flower. (You would also need to adjust aperture and shutter, if you were not shooting automatic).
Focus is okay. At first glance, it seems in focus, and that helps when you've got one shot in almost 600 competing. Upon closer glance it does seem a bit soft, perhaps from cropping, maybe from compressing for dpc.
The colors are good on this. The orangish/yellow really stands out on the white, and that is a nice attention getter and contrast. The green looks a bit dull, but it is in the background and almost secondary to the rest of the shot.
Good work and best to you in future. If I need to further clarify or explain myself, please feel free to contact me.
First of all, I don't agree with Jennifer about the tighter crop. I like the flower, and the bee's not in the best position to be featured.
Second, I like your first crocus shot (the one for Rule of Thirds) better than this one. I like the background and the lighting on that other one better. As I said in the comment on the first one, I think your score for that shot was hurt because it didn't really illustrate the rule.
Third, I like this shot and gave it a 7 during voting. I didn't go higher because I think the background is a bit distracting. If you use Photoshop, an interesting exercise might be to blur the background quite a bit, and then possibly modify the hue and saturation of the blur.