Some folks can't stand the black background from shooting with flash at the higher shutter speeds and others prefer it that way as it makes the subject stand out. Background compliments the subject but doesn't make the image I think. Trying to say that this doesn't need "nice greens" for it to be well executed macro work.
I agree. I don't think the background has to be green at all. However, I do think the background should complement (or at least not detract from) the image.
In Pegelli's image above, the background neither makes the shot nor breaks the shot---it simply "goes" with the shot. The background is easy on the eyes and it fully-allows his subject to stand out and be admired.
In studying the work of some really great macrophotographers, and in reading many of their thoughts on the subject, the consensus is pretty much that the background is as important to "get right" as is the shot itself for an overall effect. If the background is too noisy, too cluttered, and/or competes or clashes with the subject in any way, then the image is considered flawed. If the background blends with the subject, this is considered good ... and if the background actually enhances the subject, then so much the better.
We've all heard Ansel Adams' famous quote, "There is nothing worse than a brilliant image of a fuzzy concept,"
and (when applied to macrophotography) I suppose this quote could be re-formulated to say, "There is nothing worse than an ultra-sharp subject surrounded by an overall unsavory background,"
because in essence the overall "concept" is likewise lost or ruined. For example, I have hundreds of moth images, taken with razor-sharp focus, that are next-to-useless because they were taken on the screen of my back door. The sole function these images serve is for species identification, but as something pleasing to look at artistically, these images just don't cut it. The background of "my screen door" is just not what anyone wants to see, myself included.
However, had I taken the same-quality image, of the same species of moth, but where the background was a moss-covered log with perfect lighting ... then the whole presentation becomes a home run
Same subject, same-quality focusing and lighting, just a vastly-different quality in the background. Therefore, we as macrophotographers have to look at the background as being just as vital to the overall success of our images as is the subject itself.