Phorid Fly Attempting to Oviposit on a Leafcutter Ant

Leafcutter ants are a common sight in the Brazilian cerrado. I admit to being apathetic when it comes to photographing them. In order for me to turn my lens on them, something unusual generally has to be happening. In this case, I first noticed something odd occurring around one of the nest entrances. Looking closer, I could see the ants were being attacked by a small fly. I had read about that, but had never seen it personally. Intrigued, I figured I’d spend a few minutes shooting, even though I fully expected to end up with nothing usable. I was pleasantly surprised that one of the images managed to get both an ant and the fly in focus.

Fly ~1mm | January 7, 2012 | Tupaciguara, Minas Gerais, Brazil

The fly was almost constantly in motion, occasionally dive bombing an ant. I assume this is a female fly in the family Phoridae. Look carefully above and you can see the fly’s ovipositor.

At one point I saw a fly at rest near the nest entrance, possibly the same fly as above.

Fly at rest