From mid-April through to June, streams across Britain exhale a host of dancing insects, like a great smoky breath. These are mayflies, though a host of midges and other tiny flying insects join them.
Having spent up to two years as larvae (known as nymphs or naiads) living on the riverbed and feeding on plant matter, the mayfly leaves the water and undergoes a series of moults until it reaches adult form.
An entire population may hatch at once and as they catch the golden afternoon sunlight in their lacy wings, they create one of the great wildlife spectacles.
Trout, birds and other creatures feast on these fragile insects while fly fishermen use lures fashioned like mayflies to catch fish.