Mayfly nymph on bottom of stream. Note the gills on the abdomen for breathing underwater. Adult mayflies are very short-lived, typically only living about a day. They do not feed in the adult stage so as soon as the adult female emerges, she needs to mate and lay her eggs as soon as possible. Mating takes place in swarms, typically over water but also sometimes over a prominent landmark near the water.
Males fly up and down in the swarm and mating takes place in flight.
Eggs are laid in the water, usually by depositing them in flight although there are species which crawl into the water and lay their eggs on the bottom of the water body. Nymphs are aquatic and in most species feed on detritus and algae on the bottom of the stream although there are carnivorous and filter-feeding species as well. In other insects there is no more moulting after they have moulted into a stage with functional wings. Further Reading Skaife, S.H. 1979. African Insect Life.