My photographic set-up doesn’t do it justice, but this is a tiny fly with flair – the top of the thorax is black set with tiny golden hairs. But with the light shining just the right way it glistens lime green down the centre with a purple sheen to either side. The sides of the thorax look much plainer, but again, in a slightly different light the surface shimmers with yellow, purple, pink bronze and green. It’s the same on the head and the abdomen, and even the wings glisten – only the legs are matt, though they are unusually long and quirkily bristled, and shoot off backwards as if the fly is leaping forwards.
This was an innocuous looking fly swept from a sludgy puddle in a tractor rut at the muddy edge of a field about to burst into oil-seed rape yellow. It reminds me that flies, like people, are always more interesting than you first suspect. For example, it doesn’t look like it, but this fly is a predator that mashes up even smaller insects with its innocent-looking mouth. The males of many species in the family have extravagant legs with brightly coloured combs or unusual twists and swellings, while others, like one I caught 30 years ago, have exuberant genitalia hanging down from the tip of their abdomen.
In human terms, these show-off flies have pre-empted disco-glitter jackets, sequined blouses, flared trousers, finger bling, skinny-fit trousers, garish leggings and baroque codpieces – anything to catch the eye of the other sex as a prelude to coupling on the edge of a muddy field. The world of fashion is along way behind these proto-punk sexual predators.
The one I caught is less dramatic, but on its middle leg the first tarsal segment (the tarsae are the segments that come after the femur and tibia) short and slightly bent.