When we think of horned males fighting over females most of us will think first of deer. All those dramatic photos of rutting deer with locked antlers have to have their effect, I suppose, but it’s a bit bizarre that are we are so conscious of exotic wildlife and forget our own.
Of course, our own horned battlers are a bit smaller – not crocodiles or kangaroos, not even koalas or quolls, but insects. I wrote about the Rhinoceros Beetle a month ago. They are quite big enough to impress onlookers. Then I came across something much smaller still and completely unexpected, a tiny fly with the same equipment which it uses for the same purpose. Meet Wawu queenslandensis:
He’s smaller than an ordinary domestic fly but he is colourful and well-armed, and fights for females just as Rhino beetles and deer do. He has a cousin, slightly smaller but even more fearsomely (to other flies) equipped; a photo of a dead specimen is here and the pin will give you an idea of just how small he is. Females, by the way, are hornless, as they are in Rhino beetles and most deer.
It makes one wonder just how far back in the evolutionary line some kinds of behaviours really go. Do deer do it because their ancestors all the way back to the common ancestor of deer and flies, hundreds of millions of years ago, have done it? Or has it evolved separately several times, as some other features have?