There are 51 species of mayfly in Britain. They are common around freshwater wetlands, from fast-flowing rivers to still lakes, where the larvae spend their lives underwater feeding on algae and plants. The adults hatch out, usually in the summer, and have very short lives (just hours in some cases) during which they display and breed; hatchings of hundreds of adult mayflies in the same spot at the same time often occur. Many species do not feed as adults as their sole purpose is to reproduce and once they have mated, they die. The common name is misleading as many mayflies can be seen all year-round, although one species does emerge in synchrony with the blooming of Hawthorn (or 'Mayflower').

How to identify

Mayflies are delicate animals with broad, clear wings that have a lace-like appearance, very short antennae and very long, fine tail bristles. They hold their wings vertically, closed over their backs. Mayfly larvae can be recognised by their three 'tails'.

Where to find it

Various species found throughout the country.

When to find it

  • January
  • February
  • March
  • April
  • May
  • June
  • July
  • August
  • September
  • October
  • November
  • December

How can people help

Mayfly larvae and adults are food sources for many species, providing a vital link in the food chain. Mayflies are also very sensitive to pollution and are a good indicator of the quality of our rivers and lakes. But populations of mayflies are declining. The Wildlife Trusts recognise the importance of healthy habitats to support all kinds of species throughout the food chain, so we are working towards a Living Landscape: a network of habitats and wildlife corridors across town and country, which are good for both wildlife and people. You can support this greener future by joining your local Wildlife Trust.

Species information

Common name
Latin name
Other insects
Body length: 1-2cm
Conservation status
Mostly common. Yellow and Iron Blue mayflies are classified as Priority Species in the UK Biodiversity Action Plan.