Discussion in 'Fly Tying' started by sbr, Feb 17, 2014.
It depends. If the body or hackle of a floating pattern is wide enough to totally obscure the wing then from an underwater perspective it would be optional (like leaving off the wing on an Adams will not change the shape from below). Many dries however, such as Trudes and Elk Hair Caddis, have a relatively narrow body and the underwater profile would be ruined IMO if the wing was omitted. Plus the effectiveness when swung under at the end of the drift would be compromised as well since the fish is then viewing the fly from the side.
But that is the nice part of tying your own--leave off whatever you'd like and let the fish decide.
I believe I've read somewhere that due to the refractive properties of the water, trout can indeed see the wings on a Catskill-style dry.
That said, though, they're far from necessary to catch fish. Heck, they'll come up for a cigarette butt. You may catch more fish with properly tied wings, but in the case of wings on dries, I think that the number of fish you pick up with properly tied wings (that you'd miss out on without em) is probably fairly low, and even then, only the very pickiest of fish in the slow clear water.
I'm assuming you're talking about mayflies? Wings on caddis, stoneflies, midges, damsels, dragons and lots of terrestrial are definitely visible to trout when viewed from underneath. As for mayflies, I'm not an ichthyologist, but I believe trout's vision allows them to see more of the topside of a bug than I'd think possible, including wings. Whether they're necessary on a fly to catch fish is open to debate; I include them to make the fly easier for me to see.
You're asking a question which has exercised controversy among anglers for as long as dry flies have been fished and which is, of course, subject to a whole raft of variables. It is necessary to understand what a fish can see from his position underwater and referring to a book with diagrams of how interposing water and the surface film effect the diffraction and refraction of light would be helpful.
To answer your most immediate question: Can a fish see the upright wings of a mayfly? Yes, but it depends on where the fly is in relation to the fish. The fish has an upward-looking, conical field of vision through which it can see quite clearly and sharply; how large this window is depends upon how far below the surface the fish is; the deeper the fish's position, the larger his window. Eerything outside the "window", the underside of the surface film is like a mirror, reflecting whatever is below it.
Until it enters the window, the only part of an approaching mayfly seen by the trout is the dimpled pattern of its feet pressing down on the surface film. As the floating fly approaches the fish's location, the tips of its wings will appear at the edge of the window first and, once the fly completely enters the area of the window, it will be clearly visible to the fish; wings and all. If it seems a bit complicated, it is, but the optics of the subject have been well-known for a long time and the subject has been covered in many books over the years. Understanding Trout Behavior (John Goddard and Brian Clarke, Lyons Press, 2001) devotes a very clear explanatory chapter to the subject.