Mayflies (Order: Ephemeroptera)

A photograph of a mayfly resting on bracken.

Mayflies are very shortlived as adults. Most only live between one and four days.

This is a small group of aquatic insects, often referred to as Mayflies. The name comes from a Greek word meaning 'living a day' due to the adults having very short lives, usually between one and four days only. There are a little under 50 British species of Mayfly.

Main characteristics of Mayflies


Swarms of males perform a mating 'dance' over the surface of the water. When a female is found, the male flies beneath her, grasping her with his long forelegs and a pair of claspers.

A stout water net and some jars are all that are normally needed in the field for collecting Mayfly nymphs, whilst the adults can be caught in a net of the type used for Lepidoptera. The nymphs can be obtained by sweeping nets through vegetation, or thrusting under stones as they are lifted from the bottom. Living in running water, they should therefore be taken home in as large a volume of water as possible.

Most larvae can be reared without difficulty, but need cold water and some flow.

If a collection of specimens is required, it is preferable to preserve both adults and nymphs in a suitable liquid. Pinned and dried specimens shrivel badly, making identification difficult.

A good stereoscopic microscope is essential for accurate identification of the different species.

Essential reading from the Amateur Entomologists' Society

Related links: Mayflies (Order: Ephemeroptera)

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