A honey bee is the latest victim of this predatory fly. Perfectly described in the Kaufman Field Guide to North America, robber flies “are to other insects what falcons are to other birds: swift predators on the wing.” They perch in open habitat waiting for flying prey. Once in their sights, the chase is on. A swift injection of toxins from a piercing-sucking beak immobilizes, and digestive enzymes allow the fly to suck the contents. Their larvae are also predators, but live and hunt in the soil.
Size: 5 – 30 mm and more, typically 9 – 15 mm for family. For reference, a Western Honey Bee (Apis mellifera) is 12 to 16 mm (1/2 to 5/8 in).
Photo by: R. Kaleo Sills on 8/6/22 near Hamilton, MT