This image combines several techniques to create a very compelling image. By using a low angle we are looking at the flower in a way we don't normally see it. Added to that is the back lighting so that the interior of the flower is silhouetted (along with the bee). This adds dimension to the flower and reveals the delicate texture of the petals. The slight angle of the flower and stem works with the composition by reinforcing the reasonable rule of thirds usage with the leading line of the stem.
You can read the story behind the image on the original submission page.