Mayflies

Mayflies are insects which belong to the Order Ephemeroptera, the same order which also contains dragonflies and damselflies. They are aquatic insects whose immature stage (called the nymph stage) usually lasts about a year in freshwater, followed by an adult stage which is very short-lived, ranging from a few minutes to a few days depending on the species.

Adult mayflies lay their eggs on the surface of lakes or streams, which then sink to the bottom.  The naiads then live primarily in streams under rocks, decaying vegetation, or in the sediment.  Although only a few species live in lakes, they are among the most prolific. Often, all of the mayflies in a given population will mature at the same time, emerging as adults from the water and, for a day or two in the spring or fall, mayflies will be everywhere, dancing around in large groups, and seen resting on every available surface.