From the files of Donald R. Kirk:
Part 2. Mayfly Lore
In my previous blog I introduce the topic of trout fishing with mayflies. What’s the difference between a larva and a nymph? The immature stage of those insects whose wings develop on the outside of the body is called a nymph. If the wings develop on the inside of the body, we call the immature stage a larva. Nymph fishing is done with larval or pupal imitations. This is called wet fly fishing, and I am no good at it. If the fish are biting, I get strikes, but I am usually too slow to hook the fish. Fish can spit out that gob of hair on a steel hook with lightning speed.
Mayfly nymphs are robust insects well adapted to aquatic life. Depending on the species and the climate, nymphs may remain in the water for a few weeks to two years. When ready to molt into a winged mayfly, the nymphs, depending on the species, crawl out of the water on plant stems, rocks, the stream bank, or else swim to the surface and float while molting the nymphal skin. Some mayflies molt under water and must immediately swim to the surface. After a brief wait for the wings to dry, the insects fly off. This molt is called a ‘hatch’ and, depending on species and other conditions, may result in a huge cloud of thousands of mayflies in the air within a few hours. Such hatches often cause a feeding frenzy among the trout. Hatches may also be strung out over a period of days or several weeks.
Although these mayflies now have wings, one more molt to cast off the outer skin is necessary for them to mature. This second molt is apparently unique in the world of insects. No other insects are known to do this. Adult mayflies do not feed. Their sole purpose is reproduction.
While relaxed against this rock, the shade of an aspen tree has moved over me. I hear another big splash and see a glint of silver through the thick grass between me and the creek. I remove the bait hook from the fish line, and tie on one of the mayflies from my fly box. My seven–and–a–half–foot fly rod easily reaches over the grass to the water. Will I catch a fish? Read more next week on my Saturday Blog.