Jack Gartside had an interesting discussion about this
in his book "The Soft Hackled Streamer"
(www.jackgartside.com I think). In his findings the
rate at which one species was caught over the other
was due mostly to the the presentation and the color
of the fly
Met Jack a few times and know of some of his shenanigans. (Like snipping some polar bear in a museum) He's a nice guy.
On the subject of colors, "honeybugs" at the Yellow Breeches in PA are color particular to various trout. I forget which goes with what but my buddy's dad fishes there a lot and knows which. Fished with both and they really know their trout.
Murf
