Mayfly Myths:

Mayflies - as the name suggests - are often to be found flying over water during the month of May.  However.... in Britain there are 46 species of mayfly, and some fly earlier (like the March Brown) or later, than May.  Many people think that the mayfly lives for only one day.  This isn't quite true either.  Before they take to the air, mayflies live underwater as nymphs for several months or more; once able to fly, they can live for up to about four days, but many of them are quickly eaten by birds or fish, and so don't survive for very long at all.

Like dragon and damsel flies, mayflies begin their life in the water - they may live there for anything between 4 months and 3 years.  They look rather like damselfly nymphs, but have two main differences.  Firstly, a damselfly nymph has a mask (a strong lower jaw to catch prey), but a mayfly nymph has not - it's a vegetarian creature, and eats algae and other green stuff.  The second difference is that a mayfly has gills along its abdomen, whilst a damselfly's gills form a feathery "tail".  If you watch the creature swimming, you might also notice that most damselfly nymphs swim by waving their long abdomens from side to side, but most mayflies moves theirs up and down to propel through the water.  They are fast, strong swimmers, but those that live in streams are often found hiding under stones.  Simon (age 12) has sketched three different types of nymphs - see the gills on the sides of their abdomens, behind the legs, and the three feathery tails.

         

Unfortunately, when the time comes for the nymph to spread its wings for the first time, it is not able to crawl up a reed and hide, as the damselfly does.  Instead, it floats to the surface, and casts off its skin at the water's surface.  This is why many are eaten by fish.  They are called "duns" at this stage, and before they fly, they must escape to nearby plants, where they will cast off one more layer of skin.  Now they are known as "spinners", and have long, graceful bodies and tails, and glittering wings.  They don't need to eat; they eat enough while in the water to last them the few days that they will live as flies.  All they need to do is find a mate, and lay eggs in the water.  Look out for them, dancing in feathery clouds, above the water during a dry, mild sunset.