Dragonfly

The dragonfly, a swift predatory insect of ponds and streams that spends its youth underwater before emerging to fly, carries its richest symbolism in Japan. An ancient poetic name for Japan itself was Akitsushima, the Island of the Dragonfly, and the insect, called in one old form akitsu, was an auspicious sign of the ripening rice and the harvest. The samurai prized it as the katsumushi, the victory insect, because the dragonfly darts forward and, it was said, never retreats; its image was worked into helmets, sword-fittings and armour as an emblem of courage and of never turning back in battle.

Something genuinely strange underlies part of the dragonfly's old reputation for uncanny speed: its compound eyes, among the largest and most acute of any insect, contain up to thirty thousand individual facets each and give it nearly a full sphere of vision, and its four wings move independently of one another, letting it hover, reverse and change direction with a precision that modern drone engineers have specifically studied as a model for small aerial vehicles. Species-level, the dragonfly's reputation for tireless flight is best earned by the globe skimmer, Pantala flavescens, which undertakes the longest known insect migration, crossing the Indian Ocean between India and East Africa, a multi-generational relay of several thousand kilometres that dwarfs the more modest ranges of the dragonflies native to Japan's own ponds and streams.

The dragonfly's life-cycle, an aquatic nymph that climbs from the water and transforms into a creature of the air, made it, in several traditions, an emblem of change, of the summer and of the boundary between water and sky. Among peoples of the American Southwest the dragonfly is a water-symbol associated with pure water and painted on pottery, a motif belonging to those living cultures and described here from the outside. European folklore was warier: names such as the devil's darning needle and the horse-stinger cast it as sinister, with tales that it would sew up the lips of the wicked. Auspicious harvest-sign, warrior's emblem and water-spirit in one place, a devil's creature in another, the dragonfly is read very differently across the world.

European folklore's wariness of the dragonfly had a real practical use in one corner of the record: nineteenth-century English naturalists noted country people using its presence over water as an informal sign of a stream's health, since dragonfly nymphs are sensitive to pollution and vanish from fouled water long before other visible change appears, an observation modern ecologists have since formalised, dragonflies now serving as a recognised bioindicator species used to assess freshwater quality in surveys worldwide.