by L. Woodrow Ross

Created on: May 29, 2010   Last Updated: May 30, 2010

The question of why trout rise to dry flies has been addressed in many articles, by many experts. Perhaps one of the most scientific studies of why trout strike a dry fly was conducted by the late Gary LaFontaine.

He was a skilled fly fisherman, talented fly tier and innovator, as well as the author of some of the most acclaimed books about fly fishing. He wrote such classics as "Caddisflies", "Trout Flies" and "The Dry Fly".

LaFontaine spent long hours perfecting successful fly patterns. He and friend also spent much time observing the response of trout to dry flies from above the surface and also below the surface with diving equipment.

He determined that certain insects and the patterns that simulate them have certain "triggering" characteristics. Some fly patterns that did not resemble any living insect were found to have triggering characteristics that caused fish to respond aggressively.

By observing live insects in their natural environment, LaFontaine was able to isolate some of these characteristics and imitate them in his fly patterns. Many of his patterns proved very successful and are available from fly fishing catalogues around the world.

It is interesting to note that many of the "searching" or "attractor" patterns that are well known do not appear similar to actual insects, but mimic certain of these triggering characteristics. The Royal Coachman is a good example of this phenomenon.

A triggerng characteristic in the mayfly is the raised, upright wing. As it drifts downstream, the high wing first comes into the view of the trout. This alerts the fish and triggers the predatory urge to feed.

Spider patterns have heavy hackle and the large number of hackle tips touching the water produce a distinctive pattern that triggers the same urge.

As a fly tier, perfection of matching the exact appearance of an aquatic insect is not as important as understanding these triggering characteristics and building one or more of these into the pattern. A fly can look like an insect, but not be very successful if it does not have the necessary triggers built into it.

Trout rise to flies also when the drift is natural. Fly fishermen must perfect casting ability and defeat drag to produce the perfect "dead drift" to simulate the drift of an insect.

The fly must drift in the proper lane of the current. If it swirls unnaturally into another area, the fish may ignore it. They know where and how the natural is supposed to drift.

Trout are creatures of habit and instinct. They see thousands of insects drift above them. When one behaves unnaturally, they are not likely to respond. Develop an awareness of triggering characteristics, water current patterns, and fish holding areas and you will increase your odds of success.

Learn more about this author, L. Woodrow Ross.
Click here to send this author comments or questions.