Well they aren’t really monsters but I guess the top photo kind of looks like it unless you really like insects and/or you enjoy fly fishing. All of the photos here are of a species of mayfly fly fishers call green drakes. The above photo was taken with a 20x microscope lens. Green drakes are one of our favorites because they are big enough that almost all of the trout, on a river with green drakes, come up to feed when they start hatching.
Everyone knows butterflies have four stages in their life cycle: egg, caterpillar, chrysalis, and the adult butterfly. Most insects have four stages in their life cycle, mayflies included. But the four mayfly stages are: egg, nymph, subadult, and adult. The subadult stage is unique to mayflies.
Mayflies are also different from many insects in that they spend most of their life in water. The adult female lays her eggs on the surface of a river or lake (in the case of green drakes it’s a river) and sink to the bottom. The eggs hatch into a nymph which lives on the bottom eating vegetation for anywhere from several months to a year. They come to the surface to hatch out into a subadult or, as fly fishers call them, duns. Duns have wings but usually last less than 24 hours. They live such a short time they have no digestive system and are not capable of eating. They have one purpose and that is to hatch again into a sexually mature adult which mates and then the female lays eggs and the cycle begins again.
Mayflies are in the order Ephemeroptera. Ephemeral means short lived and they sure are!
These green drakes came from Henry’s Fork of the Snake River.
Sub Adult) and Imitation
They are some of the most beautiful and graceful insects alive today. They only live in cold, well oxygenated water and are therefore an indicator species. If they are in a river or lake that indicates that water is clean and oxygenated, a healthy body of water.
That first guy is scary looking! Very cool post Judy.
Excellent photos and interesting life history.