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Off with their Heads: Flies Display a New Method of Decapitating Ants

Dohrniphora longirostrata. Photo by Brian Brown.

For many years, Dr. Brian Brown of the Natural History Museum of Los Angeles County has studied flies that are known for “decapitating ants.” In 2012, he discovered the world’s smallest fly, which belonged to the family Phoridae. Some species in this family are known to lay eggs in the bodies of ants, and the resulting larvae feed inside the ants’ heads, eventually causing them to detach from the bodies.

Now, for the first time, Dr. Brown and some colleagues have observed a completely new method of ant decapitation. This time, no eggs or larvae are involved. Instead, adult female flies use their blade-tipped mouthparts to sever the ants’ guts and nerve cords, and then they grab the ant’s heads with their front legs and pull until they pop off, as you can see in the following video:

The researchers observed three different species — Dohrniphora longirostrata, Dohrniphora oricilla, and Dohrniphora conlanorum — displaying this type of behavior, and they have described it in an article in Biodiversity Data Journal.

Amazingly, it was observed by accident, and the researchers were stunned the first time they saw this intricate headhunting. They were actually looking for another type of fly in a tropical forest in Brazil, when the Dohrniphora flies showed up and began attacking injured trap-jaw ants. They weren’t interested at first, but then co-author Giar-Ann Kung turned to the others and said, “They are cutting the ant heads off!”

After Kung’s remark, they watched as the flies cut off the heads, dragged them away, and fed on them.

“Since most females studied lacked eggs in their ovaries, we conclude that this bizarrely specialized feeding is necessary to provide nutrients for reproduction in these flies,” the authors wrote.

Read more at:

A new type of ant-decapitation in the Phoridae (Insecta: Diptera)

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