Last July, while wandering about the coastal forests of St. Lucia in eastern South Africa, I happened across an intriguing scene half-way up a spiny Acacia trunk. Some diminutive gray flies were pestering a trail of ants as they walked along the tree.
The flies' exact activities were hard to observe with the naked eye, but it looked like nothing I'd ever seen. They seemed to be grabbing ants, pinning them to the trunk, and after a few seconds letting them go again.
The macro lens on my camera serves as a handy field microscope. Conveniently, the flies were so focused on attacking the ants I could place the lens nearly on top of them and observe the details of their activities without spooking them. On inspection, it turned out that the flies were stealing food.
From the Upcoming ueue, submitted by .