When mayfly duns (subimagoes) prepare to transform into their finale life stage, the imago, they first fly to streamside vegetation. There, they molt, emerging as frail, elegant creatures that gather in clouds of insects over the water for mating. The females then fall to the water to lay their eggs and die, followed by the males soon after. For anglers, a “spinnerfall” is an exciting event that will bring even large fish to the surface to feed.
