The life cycle and emergence of Ephoron virgo, a large potamal mayfly that has returned to the River Rhine
Kureck, A.; Fontes, R. J.
The mayfly Ephoron virgo returned to the River Rhine after more than 30 years absence. Since 1990, E. virgo has emerged in large masses during summer nights, sometimes affecting the traffic on the embankment and illuminated bridges. This species spends most of the year in the egg stage. The larvae live in U-shaped tubes in the riverbed, feeding on suspended particles and growing rapidly within a period of 3-4 months. The adults swarm for a few hours only and are dead by the following morning. Females remain in the subimago stage whereas male subimagos fly to the riverbank, moult quickly to the imago and then start swarming over the water. Their life cycle, timing of emergence, moult and swarming were studied.