• mayflies aidgap
  • mayflies aidgap
  • mayflies aidgap

Mayflies AIDGAP

Mayflies AIDGAP provides straightforward picture-based keys and species accounts to the Ephemeroptera of Britain.

  • Covers both nymphs and adults of all 51 species
  • Illustrated with colour photographs throughout
  • Enables identification of living specimens in the field (where possible)

Mayflies are widespread riverflies, and are well known to anglers and as indicators of high-quality habitat. They can be seen emerging from the water, resting on nearby vegetation and most commonly ‘dancing’ above head height, along the shores of many still waters and rivers.

Separate keys for the adults and nymphs guide identification of families and then species. Species accounts cover distribution, habitat requirements, conservation status and phenology.

Mayflies have a fascinating life cycle. Unlike any other insects, there are two adult stages: the sub-imago and imago (or dun and spinner). Adult males form a swarm, which females fly into to mate. After mating the female descends to the water surface to lay her eggs. Usually these eggs fall to the bottom of the water where they stick to plants and stones.

This guide is part of Field Studies Council’s AIDGAP seriess (Aids to Identification in Difficult Groups of Animals and Plants). Our AIDGAP guides are accessible identification keys, suitable for non-specialists from age 16+. As with all guides in the series, the guide underwent extensive testing before publication, by beginners and specialists alike. The author revised the key in the light of the testers’ experience.

Mayflies AIDGAP was co-created with The Riverflies Partnership.