Really like this - especially the way the background is VERY blurred. Almost lookes like the flower has been spot-editted though... the edges look outlined.
I like macros and I really like the colours in this. Too much sharpening for me (watch the halos around the edges), and I would like to see a little more DOF. I would try this one again attempting to draw out the fine purple feathery elements in the centre together with the yellow pollen - would make a nice contrast IMO (but perhaps would then not meet the challange but would make a nice image).
Very nice image. However the white/light-colored object in the center of the image is distracting. It tends to pull my eye away from the beautiful colors that are happening in your main object. Nice detail. I'm sure there is a big ol' honey bee waiting in the wings to do his job. <6>