Mayflies are famed for their short adult life. Some species have under an hour to mate and lay their eggs before they die. Their pre-adult stage, known as the subimago, may be even shorter - perhaps lasting just lasting a few minutes before they moult into their adult form. So a mayfly spends most of its life as a nymph, hidden from view under the water. Despite their short life, mayflies are a very successful order of insects. There are over 2,000 different species found everywhere except the Arctic, Antarctic and some oceanic islands.

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