Brrrrr, like pegs on bicycle wheels down a street far yet near, a female southern hawker dragonfly sets up a resonance from a whir of wings. Each of the four wings moves independently by the expansion and contraction of the four wing muscles on the thorax, going at 30 to 50 cycles a second and a top speed of 45mph, faster than traffic on the street. Up, down, forwards, backwards, left and right: she can turn instantly in six directions. There are 720 permutations, but if the order depends on the dragonfly’s intentions, there are 1,958 possible combinations for the six directions of flight.
Every movement changes the sound in this space. Each muscle-wing cycle propelling the dragonfly through the air causes turbulence, together with percussive clicking against other wings in a stridulation of ancient insect music. This is composed of individual sounds and their effects that are almost inaudible to us unless digitally modified. Recorded dragonfly flight bears a similar signature to birdsong or speech, clusters of sounds separated by pauses, like breaths between vocalisations where there is a short glide of the wings.
This may indeed be inaudible to the dragonfly, too; they cannot “hear”. Dragonfly wings have a gentle sound because of a dark panel on the forewing’s leading edge, the pterostigma, and together with the wing’s microstructure, it has an anti-vibration effect, preventing destabilising “flutter”, enabling gliding and dampening noise. Listening, the “noise” may be softened, yet it is loud with presence and moment, and loaded with the electricity of enchantment. The beat between wingbeats is not silence but the ambient sounds of a border market town sticking to reverberating autumnal air.
Nevertheless, this code of wingbeats-glide-wingbeats stretches back through evolution to the Carboniferous era, from which we and our mammalian ancestors are absent. In about 30 cubic metres of garden, the dragonfly zips over a patch of grass, between shrubs and small trees, pausing to hover, to alight on a stem, then continues tracing aerial pathways that link the present to the deep past.
She flies through the back door into the kitchen. The sound becomes weirdly ominous as it transgresses boundaries that have separated us for millennia. We are enclosed in the centre of this 300m-year-old whisper.
• Under the Changing Skies: The Best of the Guardian’s Country Diary, 2018-2024 is published by Guardian Faber; order at guardianbookshop.com and get a 15% discount
