Killer, At Work
Reminder: You can enlarge any of the photos in this blog by clicking on it. Click again for a full-screen image.
I went over to Sabino Canyon early this morning and spent several hours wandering around in the dense brush that borders Sabino Creek. Towards the end of my hike I happened upon a Robber Fly, a/k/a Assassin Fly, resting on a bush. The fly sat there quietly its mind on things other than me and my camera, and I took its picture.
A Robber Fly is an amazingly well-adapted predator. Think of it as sort of combining the traits and abilities of Peregrine Falcons and rattlesnakes and you get the picture. It is a classic ambush predator. It sits quietly on a leaf or a twig, just as this one is doing, waiting for another insect to come flying along. It has extremely good vision and it can fly with lightning speed. And, when a potential victim comes within range, it pounces, running it down in the air, and seizing it. It then injects a venom into the prey that almost instantly paralyzes and then kills it. The venom serves double duty. Just like rattlesnake venom it contains digestive enzymes that dissolve the prey’s tissue. The Robber Fly can drink its victim’s liquified tissues at its leisure.
Look closely at this fly and you’ll see its predatory tools. Its feet end in talons, not unlike a hawk or falcon’s talons. Its eyes are huge in proportion to its body. Its thorax is heavily muscled, designed to rev up its wings for sprinter’s speed. It has a black, chisel shaped proboscis that it uses to punch through the exoskeletons of its victims so as to be able to inject venom.
I’d only taken a couple of pictures of this fly when it flew off. I assumed that my camera’s flash had disturbed it and that it was seeking peace and quiet. But, within five seconds it returned to its perch. And, to my amazement, I discovered that it had seized a victim. The Robber Fly had captured a smaller fly and was now dining.
Five seconds’ work. That’s all it took. The wonders of evolution never cease to astonish.
Images made with a Canon 5DS-R, 180 f3.5L Macro Lens assisted by Canon 600EX-RT Speedlite, ISO 200, M setting, f16 @ 1/160.