Large Dark Olive Mayfly - Baetis rhodani


    This family is characterised by two tails and tiny oval shaped hindwings. The pairs of short veins between each of the long veins in the forewing indicate that this is a Baetis species. B. Rhodani is the largest sized member of this group, especially the early hatch, later in the year specimens become smaller. It is also one of the earlier mayflies to hatch out.

    Identification difficulty

    Usually around moving water.

    When to see it

    All year round, but especially from March until autumn.

    Life History

    Once mated the female finds a partially submerged stone and folds her wings back over her body. She then crawls through the water surface and lays her eggs directly onto the submerged stone. She lays around 4500 eggs individually side by side so that they form a discrete patch of eggs on the stone. The larvae generally live amongst the sand and gravel on the bed of moving water. They feed by scraping algae from submerged stones, etc. or by collecting fine organic materials from the bed.

    UK Status

    Frequent and widespread in Britain

    VC55 Status

    Common in Leicestershire and Rutland.

    Leicestershire & Rutland Map

    UK Map