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07 June 2015

Robber Fly in Tabuk – Record by Viv Wilson

Viv Wilson sent me a photograph of an Asilidae that are part of the robber fly family, also called assassin flies, that h took in his garden in Tabuk recently. He has kindly allowed me to use the photo on my website and it is reproduced below. They are powerfully built, bristly flies with a short, stout proboscis enclosing the sharp, sucking hypopharynx. The name "robber flies" reflects their notoriously aggressive predatory habits; they feed mainly or exclusively on other insects and as a rule they wait in ambush and catch their prey in flight. There are over 7000 described species. And in general attack a very wide range of prey, including other flies, beetles, butterflies and moths, various bees, ants, dragon and damselflies, ichneumon wasps, grasshoppers, and some spiders. The fly attacks its prey by stabbing it with its short, strong proboscis injecting the victim with saliva containing neurotoxic and proteolytic enzymes which very rapidly paralyze the victim. Asilidae generally occur in habitats that are open, sunny, and dry, even arid. Asilidae occur in all zoogeographical regions except Antarctica, however, the highest levels of biodiversity are in warm climates with arid or semi-arid regions tending to have the greatest variety of species.