by Matthew Cobb
While I was asleep, my Tw**ps were chatting about robber flies. So I woke up to these great pictures. Robber flies – technically the family Asilidae – are strong and agile predators that as adults feed on other insects, sometimes much larger than themselves, catching them in the air. The result of such a chase is shown in this fantastic photo by Sarah J. Semmler (@SarahSyrphid), showing a robber fly that had just grabbed a meadowhawk dragonfly:
What a fantastic photo! Sarah also tw**ted this photo of a robber fly by Seth Patterson from Bugguide, pointing out the well-developed ‘claws’ on the end of the tarsi, and the spines all over the legs which would make it easier to grab prey in the air.
They will eat anything, including stuff much smaller than themselves, as seen in this photo by Muhammad Mahdi Karim of a Pegesimallus fly nomming what looks like a small fly:
And look at this, the massive ‘Florida bee-killer’, Mallophora bomboides, photographed by Nancy West, University of Florida. That’s a honey bee it’s eating!
And people think that mammals are beautiful predators!
According to Wikipedia (sorry) there are over 7,000 species of Asilidae. You can find tons of stunning photos on the internet.
Although the life-style of adult robber flies is well known, the ecology of the larvae – which interest me – is much less well understood. Larvae of some species appear to be classic detritus-feeding maggots, while others are reported to eat insects but mainly eggs and other larvae (i.e. they bumble across them, perhaps guided by smell and taste, rather than being cunning predators).