Drake Mackerel Mayfly Epherema vulgata
The Drake Mackerel Mayfly is a rather large species. Excluding the wires attached to the rear males measure some 15 to 21 mm, females 18 to 24 mm. The wires of the females however are much shorter than the males'. The body is creamish with brown or black triangular spots on the sides. There are black spots in the wings as well and the veins are usually quite dark. Of the Epherema species this is by far the darkest one. Adults are seen in May and the beginning of June.
The larvae live in the substrate of pools and ditches. They dig a u-shaped tunnel in which they live. By means of their gills they keep on pumping water through the burrow. From the water they take oxygen en minute particals of decaying plant material (the debritus) on which they feed. Full grown larvae measure up to 18 mm.
They stay in the water for two years. Then they float upwards where the fly itself appears, usually on the surface of the water. This subadult immediately flies off to a plant or a tree, where it sheds its skin for a second time, as do all Mayflies. Only then is it mature.
The males swarm aside the water. Females are attracted to these swarms and fertilized. After copulation the male dies. The female develops some 600 eggs. These are deposited by flying over the surface of the water, sometimes descending to the surface. The tip of the body is then put inside the water and a couple of eggs are released. After she has laid her last eggs, the female dies, usually on the surface at the same spot the last eggs were released. Because of the way the eggs are laid and the female dies, various fish are fond of these mayfly. The flies are artificially imitated by fishermen.