Insects are the root of flyfishing. Without them, there is no basis for our sport. This fact alone is justification enough—to my way of thinking, at least—for possessing a working knowledge of insects and their behavior. Practically speaking, a knowledge of insects helps us predict where and when the best fishing is likely to occur, greatly increases our chances of finding feeding fish when we do get on the water, and informs our choice of fly pattern in any given situation.
Fly fishing 101: Knowing your bugs, made easy
by John Juracek - Thursday, May 13th, 2021