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Robber Flies Capturing Prey

8-3-16  robber fly 009The robber fly family, Asilidae, is one of the largest families of flies.  All robber flies are predaceous and are recognized by their long bodies, forward-facing beaks and a tuft of hairs above the beak.  You find them on the ground or on leaf tips and other sunny spots where they survey the area for flying insects.  Once a robber fly has spotted a suitably-sized prey, it darts out and impales it with its stout beak.  It then inserts its needlelike “tongue” into the prey’s neck, eye or other weak spot, immobilizing the insect and liquefying its innards with an injection of saliva that contains nerve poisons and enzymes that break down proteins. Finally, it drinks its meal.  Pictured is a species of robber fly in the genus Diogmites, whose members are known for dangling by a foreleg while dining.

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7 responses

  1. Betsy Janeway

    AMAZING photo of robber fly hanging by foreleg. See you in Warner Saturday! Betsy Janeway

    August 5, 2016 at 8:50 am

  2. Guy Stoye

    One day, sweating in a swamp many year ago and plagued unmercifully by deer flies, I was about to swat one that had landed on my forearm. Down zoomed some insect which pounced on the fly a split second before I swung to kill the little tormentor.
    To my amazement, the attacker clutched the fly and flew off with it. I was seeing a robber fly in action for the first time.

    August 5, 2016 at 2:07 pm

  3. Nice capture Mary.

    August 6, 2016 at 9:05 am

  4. Amazing and great capture, Mary!

    August 6, 2016 at 9:45 pm

  5. I”m a bit late looking at this post Mary after catching up on email, but simply exquisite – capturing such a clear photo of a robberfly feeding while dangling from the tarsal claws on one leg – you never cease to amaze me with your photos, and your lore. Thank you, thank you, thank you! Craig W.

    August 22, 2016 at 9:33 pm

    • Oh, you’re so very welcome, Craig. So nice to have a kindred spirit like you!

      August 23, 2016 at 9:28 am

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