Instinctively, I shied away from the buzzing near my ear, thinking it was a wasp. No, just a harmless hoverfly, a blur of wings and a body fringed with golden hairs, perfectly stationary, as if dangling by an invisible thread in the afternoon sunshine.
Hoverfly flight is a wondrous thing, made possible by halteres: flexible, vibrating, club-shaped rods under each wing. They act like stabilising gyroscopes, constantly feeding back information to the insect about its position, allowing instant, precise flight adjustments. The slightest warping of a wing translates into darting, directional flight. And that’s what happened as I watched, listening to its invisible, barely audible airwaves, spreading like ripples in a puddle from this aerial diadem.
I found it again, settled on a leaf. There are dozens of similar species of these wasp mimics, many tricky to identify, but naming this one was easy for someone who spent formative years in the 1950s reading American Batman comics. It was Myathropa florea, bearing the unmistakable black silhouette of the caped crusader’s outstretched wings on its shiny thorax.
Airborne once more, it descended in a series of hovering steps on to the rim of a flowerpot filled with water and decaying leaves. The aquatic larva of Myathropa is a rat-tailed maggot, an unattractive secret identity for an organism that lives in stagnant, water-filled rot holes in trees, aided by a snorkel, and eventually transforms into this insect of exquisite beauty. A few minutes’ searching revealed several larvae in discarded water-filled pots of rotting leaves behind the greenhouse. I tipped one into a shallow dish for a closer look.
The maggot’s snorkel is more adaptable than the holiday reef diver’s equipment because it automatically adjusts to water depth. When rain raises the water level, up goes the maggot’s snorkel to keep pace. With just a little water in the dish it was stubby, but when I added more it extended until it reached almost three times its body length.
Hoverflies, like this one bearing the Batman insignia, are as important as bees for pollinating many wildflowers. A good reason to leave the rest of those unsavoury water-filled flowerpots behind the greenhouse undisturbed as nest boxes for superheroes.