Ephemeroptera

The Ephemeroptera, commonly known as mayflies, are an order of aquatic insects found across Europe, with over 300 species. They are slender, with delicate bodies ranging from 3 to 30 mm, featuring two long tail-like cerci and often a third median filament. Adults have short lifespans (hours to days), with large, transparent wings held upright at rest, as they are physically unable to fold their wings along their bodies, and are known for synchronized emergences near rivers and lakes. The nymphs are aquatic and gill-bearing, live 1–2 years, feeding on algae or detritus. Key European genera include Ephemera and Baetis. They play a vital role in freshwater ecosystems as prey for fish and indicators of water quality.