This image has been shot vertically, presumably to enable the photographer to capture more of the person in the image. The image may have been cropped, however, given the nature of a lot of Avedon's images, I would say it was shot in this way. The image has been shot pretty much face on, so the photographer would have been on the same level as the subject. The focal point is of course, the model himself, and the bugs that are all over him.
Since this is a studio portrait, the lighthing will probably have been artificial. From the looks of things, the model has been lit head on, as the whole mid-portion of his body has the most light on it.
The image is black and white, following the style of most of Avedon's portraits. Avedon once said that he did this to let the natural character of his subjects flow through, and portray themselves in the image. The image looks like a straight print, with very little manipulation.
The image caught my eye because of the bugs that are all over the subject. We're not told why, or what this is about, but it made me take a second look.