Life of a Salmonfly
The adult life of the salmonfly (Pteronarcys Californica) begins in the nymph stage. Salmonflies live two to three years as large armor plated nymphs, crawling the river's bottom in search of fast riffley water. A month or so before the hatch the nymphs make an upstream migration. This is to compensate for the river's swift current carrying them and freshly laid eggs down stream during their hatch. When time is right, they crawl out of the river to hatch.
Early evening through the night, winged salmonflies emerge from their former nymph bodies. They are most vulnerable at this time. The empty nymph husks remain clinging to logs and tree trunks for months.
A freshly molted salmonfly must pump their new wings full of blood.
When the sun is shining, salmonflies are out and about. Soon they will begin to search for a mate. The old saying is true... when it's dry, they will fly. Before they mate, salmonflies make a second upstream migration, also to make up for the river's powerful flow. This time they fly.
It is the males job to seek out their larger counterparts.
After mating, females develop egg clusters and oviposit them into the river. After mating and dropping eggs, salmonflies live only a short while. They supply nourishment to the entire canyon, feeding a variety of birds, reptiles, fish, and even black bear (I have only seen them in the canyon during the hatch).
The entire process, from hatch to expiration lasts only two weeks.