Invertebrates
Green Drake Mayfly
Ephemera danica
On a warm May evening over a chalk stream, clouds of green drake mayflies lift from the water, and every trout in the river rises to feed.
Overview
The green drake mayfly, Ephemera danica, is a large European mayfly whose burrowing nymphs live in river silt and whose adults emerge in great numbers in late spring. Its long underwater life, short adult life, and spectacular hatches make it one of the best-known insects of European rivers.
A life mostly under water
For almost its whole life the green drake is a burrower in the silt, and the winged adult exists only to mate and lay eggs before it dies.
Status
Not Evaluated, but sensitive to pollution.
Green Drake Mayfly: common questions
How long does a green drake live?
It spends one or two years as a nymph, but the adult lives only a day or two.
Why do adults emerge together?
Mass emergence swamps predators with numbers, so enough survive to mate and lay eggs before they die.
What is a dun and a spinner?
A dun is the first winged stage, a dull subimago, and a spinner is the shinier adult that appears after one more moult.
Where is the green drake found?
It lives in clean rivers, streams, and lakes with silty and gravelly beds across Europe.