Seen between May and August, the mayfly dances along the surface of our canals and rivers in search of a mate.
Mayflies are threatened by pollution, which can kill up to 80% of their eggs before they hatch.
Mayfly facts
Scientific name: Ephemera vulgate
Family: Ephemeridae
Diet: Juveniles (nymphs) eat algae and vegetation; adults don’t feed
Predators: Fish, like trout and salmon, and small birds. Nymphs are preyed on by amphibians, as well as invertebrates like caddisflies, stoneflies and dragonflies
Size: 1.5-3cm
Lifespan: Two years (the majority of their lifecycle is spent as a nymph)
About mayflies
Mayflies have been around for more than 300 million years, with fossils older than the dinosaurs. They were the first winged insect to evolve and, today, there are 51 species of mayfly in the UK – and more than 3,000 worldwide.
The Ephemera vulgate is most commonly seen on slow-flowing and still waters, like our canals. You might also spot the 'green drake' mayfly (Ephemera Danica), large dark olive (Baetis rhodani) and large brook dun mayfly (Ecdyonurus torrentis).
Mayflies and our canals
Mayflies typically live in freshwater habitats. They spend their time as larvae underwater, before emerging on the wing for their last summer as adults.
Adult Ephemera vulgate have creamy-yellow abdomens with dark markings, veiny and translucent wings and three long tails. Female mayflies are slightly larger, while males have bigger eyes and pincers near the tails.
What do mayflies eat?
As nymphs, mayflies feed on algae and plant matter beneath the water’s surface. When they emerge as adults, they lose any functioning mouthparts. Instead of eating, adult mayflies focus their energies on breeding.
How do mayflies breed?
Contrary to popular belief, some mayfly species live for longer than a day – but not much. Mayflies spend the majority of their lives (about two years) underwater as nymphs.
Once they mature, they emerge from the water to mate. There are two adult stages. When they first appear out of the water, they’re a dull brown before moulting to their full adult form – and they’re the only insects known to moult as adults.
Males gather in swarms to perform their courtship dances. After successfully attracting a female, the mayflies will mate on the wing. Females then lay their eggs in the water by dipping their bodies beneath the surface and dropping the eggs.
Where do mayflies live?
Mayflies are found all over the UK, and you can find them on almost all our canals. They prefer clean waters, like rivers, ponds and lakes with gravelly or sandy areas for the nymphs.
Despite their name, mayflies can emerge at any time in the spring, summer and early autumn.
They’re most active between April and August, so head to your local canal on a warm evening to spot them on the water’s surface. During mating season, you might spot swarms of males rising and falling in dance.
