The mayflies’ song

Time stands still to listen

I try my best not to have favourites amongst the invertebrates. It isn’t for me to say which are the admirable species and which the disreputable amongst them. But a person’s heart loves what it loves. And my heart soars with the rising of the Ephemeroptera. The mayflies, the ‘uprights’ if you have been brought up within certain old traditions of fly-fishing. Shadflies, I think they are called in some far-away parts of the world. Oh, but I have led you astray already. I have called them flies and the word itself is enough to make people itchy and irritable. I don’t want that. What if we were to whisper the old honorific name which the ancient Greeks gave them: the ephemera, the transitory ones. Would you read on? To the Greeks the ephemera rose from the water as if they were a chorus on a stage, dressed for tragedy, their choreography precise, their coordinated movements mesmerising. And within the space of a day the audience watched them dance their lives away and fall, spent, onto the water. To be swept away in their thousands. Leaving no trace.

Down below our house, the River Eden is quietly humming an old tune. So old that almost all the sounds have been worn and washed away, leaving just the dip and surge of mayflies dancing where notes would once have been. A melody so ancient that by comparison even the river is just a child, still waiting to discover her destiny. How many generations of rivers have sung this tune on an early summer morning? Unthinkably many. The song of the mayflies was composed in the late Carboniferous period. The plates of rock which we now call Britain were down near the equator, drifting dreamily northwards. Dinosaurs were a crazy unpublishable fantasy, way too far out in the future.

Set against the long lineage of mayflies an individual river is just a spark struck in the darkness, her short life burning brightly before a glaciation or a tectonic upheaval sends her back into the continuum of water. The stars wink indulgently to each other when they see us so confidently drawing rivers on our maps, the blue ink feigning permanence. To the night sky a river is like a silvered eel, wriggling and restless, not long for this world.

If the grinding millstones of time can pulverise mountains and bury oceans, how can these ephemera, the most delicate of insects, continue to perform their graceful tragedy down the millennia? Sit on the riverbank late in the morning and watch closely. Below the rippling surface preparations for a performance are underway.

The nymphs, the aquatic larval stages of the different Ephemeroptera, of which there are fifty or so species in the British Isles, are specialised in form and function. Some graze on pebbles in the full force of the current, flattened like leggy beauty spots on the rock’s face. Other species burrow into silt and glean the river’s leftovers. They grow and shed their skins every month or two, passing through multiple instars, waystations of transformation. Their underwater pilgrimage lasts a year, maybe two. All the while their external gills flutter in the watery breeze. The little flames of their lives burn brightly and it is only in unpolluted, highly oxygenated water that the ephemera can survive. In so many of our rivers their song has been forgotten.

The nymphs appear to me, when I watch them through a glass-bottom bucket, to lead solitary lives. But how am I to know what messages pass between them, what stage directions are written into the script to synchronise their final act?

Leaving the river is not easy. Water is as sticky as glue. Its skin as tough as old boots, laced up tight with surface tension. On the right day, at the proper hour, the nymphs, en masse, swim up to the silvered roof of their world and must somehow break through the looking glass. To make this move from one world to the next they have to leave themselves behind. The skin of their aquatic selves splits one last time and the newly winged supplicants squeeze out through the meniscus, crumpled and vulnerable. Those who survive the next few minutes take to the air and congregate briefly above the river, staring at each other in amazement.  

Soon the congregation disperses. If you look closely, you will find them hanging above the water on the underside of an alder tree’s leaves or clinging upside down beneath twigs and branches. The stage is being reset for the last scene. Unlike any other order of insects, the ephemera make one last change of costume for the finale. Just a few hours after they left the water, the dull, dun skin of their sub-imago form is shed to reveal the brightness of their breeding livery. The blue-grey opacity of the wings which carried them up from the water is left on the ghostly husks from which the final adult stage emerges, carried on new translucent wings which sparkle in the sun.

Above the deep river run at the foot of Pendragon castle, hundreds of males synchronously rise up and bow, rise up and bow again and again, their long formal tails held wide and steady. The females fly through them and are mated on the wing. These beings have no mouths. They have only the tiny stores of energy they brought within them, which they expend without a thought. They have already left their past behind so many times and have no bridge to the future. So they dance in order to waylay the present moment and hold it aloft, spellbound, stilled. In this brief interlude the mayflies halt the great millstones of time. They do not seek immortality in monuments or memory. They weave it anew from nothing but air and water and movement.

Soon the males begin to falter and fall. The females turn upstream and descend to the water’s surface, curtseying repeatedly as they press their eggs down through the meniscus. Within minutes they too are spent and lay their bright wings flat on the cushion of the water’s surface tension. The river reaches the end of the old song she was humming and, for now, is silent.

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