Since yersterday, I have been an eye-witness to a robbery taking place in my home garden at broad daylight. A pair of robber flies has taken residence on some of the sticks that I have erected to invite dragonflies to perch. Ssing them as launching pads, the robbers have been launching precision air strikes to hunt on various tiny insects.
With their large compound eyes and three simple eyes situated in the depression in betweeen, they have amazing eye sight, and hardly any fly in the vicinity that falls within their target size goes unnoticed.
On several occassions I saw a perched individual fly in the opposite direction to take insect prey in mid-air!This particular species of robber fly, measured barely a centimetre in length, was a pretty amazing killing machine.
Once the victim is caught in mid air, it returns to the perch to 'process' the meal. First, it uses its short proboscis to inject venom— its saliva containing neurotoxic, and proteolytic enzymes to first paralyze, and then to digest the insect's inner parts. Thereafter, puting its proboscis to good use, it cold-bloodedly sucks the liquified meal like a milkshake.
And once it is done, the victim's lifeless outer casing is discarded like a used satchet.
Robbers belong to insect order: Diptera to which 'true flies' belong. They possess a single pair of wings. All Robbers belong to the family, Asilidae. Their quite impressive prey menu includes other flies, beetles, butterflies, moths, bees, wasps, spiders, dragonflies, damselflies and grasshoppers!