Trout feed on aquatic and terrestrial insects, and mayflies (an aquatic insect scientifically called mayflies) are the best known of all trout foods. They occur virtually everywhere in the world, are prolific, and in most places #1 on a trout’s menu.

Despite their name, mayflies have nothing to do with the month of May. Their life cycle begins at different times of the year, depending on their type and other natural factors such as water flow and temperature. Simply put, the beginning of your life is related to life final of the adult female. The life cycle of a mayfly generally lasts about a year and occurs in four distinct stages: the egg, the nymph, and two adult stages; the adult sub-imago (brown stage) and the adult imago (rotary stage).

Briefly, at the beginning of the spinning stage, the female and male come together and mate in midair, fertilizing the eggs. The female spinner lays eggs on or below the surface of the water in a lake or stream, and the eggs sink and attach to the bottom structure. Spinners, both male and female, quickly die of exhaustion. This final step concludes the life cycle of the mayfly.

These tiny eggs hatch in a matter of days and the tiny nymph is “born”. At this early stage, the nymph is too small to be trout food. As the nymph develops, she grows and becomes trout food as she moves along the bottom, or as she floats or swims to the surface of the water for the first adult stage, the brown. This movement on the bottom or on the surface makes the nymph more vulnerable to trout feeding. This metamorphic action is an expert fly fisherman’s dream come true.

Mayfly nymph imitations that roughly represent the nymph crawling, swimming, or emerging are trout-catching flies in their prime. Fished with a sinking fly line, a fly line with a sinking tip, or a weighted artificial pattern are all effective at this time. The imitation nymph can be weighted with lead wire wrapped around the shank of the hook before rigging the fly, or by tying the nymph with the addition of a heavy bead head for added sinking ability. Otherwise, an approximate representation of natural size, shape, and color will be adequate.

Pheasant’s tail nymph and ribbed hare’s ear nymph in shades of tan to brown, light olive to dark green, and light gray to black are excellent mayflies patterns for the angler’s fly box. These are a favorite of trout nymphs.

While the dry fly angler has a visual response when his dry mayfly is caught at the surface of the water, the knowledgeable nymph angler will generally catch more trout. The nymph angler cannot always see the fly below the surface. You are looking for the flash of brightly colored trout when the fish “takes” the artificial, any bulge on the surface of the water, a sudden movement of the fly line or leader, or if the trail line stops abruptly on the medium. Drifting All of these indications can represent the presence of trout and should be a signal to “set” the hook.

If you haven’t considered fly fishing with a mayfly nymph, I urge you to give it a try. There is a learning curve, but the results will make you a more productive fly fisherman.