The Robber Fly are also known as the Asilidae known for their attacking (predatory) behaviors. Robber flies are opportunistic predators, their diets often reflecting prey availability in a particular habitat which is located in parts of Georiga! Robber Fly adults attack wasps, bees, dragonflies, grasshoppers, other flies, and some spiders. Robber flies seize their prey in mid-flight and inject their victims with saliva containing neurotoxic and proteolytic enzymes.