Two important orders of natural aquatic flies for fly fisherman are Ephemerop-tera and Trichoptera. Mayflies have upright wings while sedge flies have two pairs of hairy wings. When the sedge fly is at rest, the wings have a roof-shaped, triangular appearance.
Natural upwinged flies rest only their legs on the water’s surface. No other part of their body touches the water. Most artificial dry flies are designed to copy this. In the standard dry fly only the hackle tips and tail fibres sit on the water — its shoulder hackle needs to be stiff enough to support the hook. With some dry flies, however, the fly body rests on the surface to imitate emerging nymphs and duns in the process of hatching from the water.
In the early part of the season, trout feed on nymphs and insect larvae which live below the water’s surface. Hatches of upwinged and sedge flies are much more important on rivers than still-waters because insects are one of the river trout’s main food source. Stillwater trout feed on insects, but they also eat small fish such as stickleback and perch.
Fly hatches can occur almost every day of the trout season – except perhaps on the coldest, wettest days. But as the warm weather approaches, hatches increase tremendously, and trout feed off the surface much more regularly. In fact, trout may become preoccupied with flies on the surface.
An abundant hatch of a particular fly species can mean that trout become selective towards that fly, ignoring all other flies. Only an imitation of the hatching species can induce trout to rise. This is the great challenge of dry fly fishing. You first have to recognise the natural fly, noting whether it is an upwinged fly, a sedge fly or any other species.
Try and match the natural fly with an artificial of the same overall shape and colour. If sedges are hatching or egg-laying, use a sedge imitation of approximate size and colour. If upwings are hatching, use a shoulder-hackled dry fly, and again match it as closely as possible in size and colour.
Wings or hackle?
It is not always necessary for the dry fly to have wings. Although the imitation looks more lifelike to the angler, trout rarely seem to notice that the wings are missing. Often the blur of the hackle, seen from underneath, is a sufficient suggestion of upright wings. Winged sedge patterns are also effective, but many fly fishers don’t use winged imitations of upwinged species because it simply isn’t necessary.
Buoyant materials and fine-wire hooks help the fly to float. It is also essential to coat the artificial fly with a water-repellant grease, either solid or solvent-based, to ensure that it floats for a long time. But apply the repellant sparingly to avoid clogging the hackle fibres.
The fly leader shouldn’t be greased. If it is, it floats on the surface of the water, and the trout can see it. To ensure that it sinks, rub a bit of mud on it.