Common Brown Robber Fly

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ommon Brown Robber FlyFamily: Asilinae
Common names: Common Brown Robber Fly
ALA reference

Robber flies are fast and agile, and have excellent eyesight, which makes them very successful predators. They prey mostly on other insects such as flies, wasps, bees, grasshoppers and dragonflies and will even take spiders. They normally catch their prey in mid air and then return to a perch to digest the meal. This is done with their stabbing proboscis that injects saliva containing neurotoxins and enzymes into the prey to kill it and dissolve the body tissues. The liquidised remains are then sucked up through the proboscis. Robber flies deposit their eggs on plants or in gaps in the soil. The fly larvae, which are also predators, live in the soil or in rotting wood feeding on eggs, larvae and soft-bodied insects.

I spotted this common brown robber fly on the bollards bordering the Reserve at the end of Eddystone Road, where it had established its perch in a nice sunny location. It continually made hunting forays always returning to the same spot. I estimated that it was about 30mm long and probably the largest robber fly I have seen. Check out those magnificent eyes. (January 2009)