There are around 2,000 species in this order of insects. There are around 650 species in North America. Adult mayflies have a very short life span, in fact the name of this order, Ephemeroptera, comes from the Greek word ephemera and means short-lived. In some species, the mayfly adult lives only a few hours!
Mayfly larvae live in the water and eat aquatic plants. They develop into a immature winged form called a subimago. The subimago molts and becomes an adult. Mayflies are the only insect species that molt after they have developed wings!
Adult mayflies don't eat. They quickly mate and die. The male dies right after mating, and the female dies after she has deposited her eggs.