Robber Fly

About the Robber Fly

If dragonflies are the fighter jets of the insect world, robber flies are the ambush interceptors. A robber fly picks a sunny perch, watches the airspace with huge wraparound eyes, and launches at passing insects, hitting them in mid-air and riding them to the ground - where a stab from its stout beak injects saliva that both paralyzes the prey and liquefies it for drinking.

Nothing of reasonable size is off the menu: bees, wasps, grasshoppers, beetles, dragonflies, and other robber flies all get taken, often prey larger than the fly itself. The distinctive bristly "mustache" (the mystax) protects the fly's face from struggling victims.

Texas is rich in robber flies, from small bee-mimicking species to the giant Beelzebub bee-eater, one of the largest flies in North America. Most share the look: bearded face, humped thorax, long tapering abdomen, and powerful bristled legs for grabbing.

They are harmless to people who leave them alone and fascinating to watch work - apex predators of the trail edge, one perch at a time.