The final stage of a mayfly’s life cycle is called an "imago" or “spinner,” and clouds of these mating insects are often visible dancing in the air above a river. Spinners are usually easy to identify by their transparent wings, extra-long tails, and large eyes.
The aquatic insects are born in the streambed and live as nymphs for up to a year. The nymphs then rise to the surface, where the winged dun breaks free of the nymphal shuck. The duns fly to streamside vegetation, where they usually live for just a day or two before molting into adults. These spinners then swarm over water.
After mating, the female spinners fall to the water, where they lay their eggs and then die, their bodies providing food for hungry fish and birds. Male spinners usually fly back to streamside vegetation and die, as well.
