Trout Flies: The Mayfly

Among the many trout flies we have in stock, it’s well worth checking out the mayfly ranges. Mayflies (ephemeroptera) are dainty insect with lacy wings and a slender, forked tail that trails behind it in flight. Commonly called dayflies because of their short lives, adult mayflies live only a few hours or a few days. Because they do not need to eat they usually have undeveloped mouthparts. They actually are not true flies. A true fly has two wings whereas a mayfly has four. Mayflies lay their eggs in streams and ponds. The females are known as spinners. After ovipositing they lie on the surface film of the water with their wings outstretched. At this stage they are termed spent spinners or spent gnats.

Young mayflies are called nymphs or naiads. A nymph breathes through its gills and feeds on water plants and it can live for a few months to two years in the water. It also serves as food for fish. Before their first flight freshly-hatched mayflies float on the surface to dry their wings. The scientific term for this is sub-imago, but in angling parlance this stage in the insect’s life is known as the dun. Once it leaves the water it sheds its skin and becomes a winged sub-imago, or sub-adult. Several hours later the subimago sheds its skin and becomes a fully-grown adult. Many artificial trout flies imitate these stages in the mayfly’s life.