During a recent amble along a nearby streamside path, I passed from dense shade beneath floodplain sycamores into an opening where Jerusalem artichoke gleamed yellow in a narrow wedge of sunlit glade. Several bumblebees were working the bright blooms. As I watched, a whirring fly-like creature simply snatched a hovering bee in midair. An attack that came out of nowhere, quick as lightening, deadly as a gunshot to the head. One moment the bee was going about its nectar-gathering business, the next it was being carried off to become a flying carnivore's lunch.
The perpetrator was a giant robber fly, a predatory insect also—unsurprisingly!—sometimes called a bee killer. In fact, the oversized assailant looked rather like a cross between a long-bodied horsefly and some sort of wasp—sporting spiny legs, large complex eyes, a hairy thorax, and yellow bands along the abdomen. The formidable aerial assassin was easily an inch long.
There are several thousand species of robber flies worldwide, about 1000 species in North America. The one I saw and later photographed is probably in the Promachus genus. Giant robber flies are voracious, and will catch and eat practically any other bug that flies—from bees to dragonflies, even butterflies! If they were the size of pit bulls, they'd nab us, too, and summarily suck out our fluids, and we'd wind up nothing more than rattling bones in a wrinkled bag. Not a pleasant fate to contemplate.
I watched as the big robber fly devoured its latest meal. Nature isn't always pretty; the real world outdoors isn't scripted like a Disney feature. Times are quick and hard, life and death have equal billing, and scenarios get pretty messy sometimes. I don't think you have to dwell on this when writing about nature, but I do believe you need to be honest.
Is a robber fly any less fascinating than a bumblebee? Whoever named it certainly must have thought these winged attackers worthy—in fact, they were in obvious admiration because the genus name, Promachus, comes from the Greek, promachos, which means "fighting in front," a champion, a "defending deity." Quite the honorific…unless you're a bee.