The world is enormous, but most of its inhabitants are very, very small. Insects make up 80 percent of all organisms on Earth, yet we know relatively little about them. Take phorid flies, for example. There are more than 4000 species in the Phoridae family, many with gruesome habits that have earned them descriptors like “coffin flies,” “bee-killing flies,” and “ant-decapitating flies.” A species in that last group recently revealed a never-before-seen method of removing ants’ heads.

If you’ve got the stomach for it, the video above is absolutely fascinating. (If you don’t, you should probably stop reading now.) Scientists knew that some parasitic Phoridae flies lay eggs in ants’ heads. The eggs become larva, which then eat their way through and out of their hosts, removing the ants’ heads in the process. But researchers noticed female Dohrniphora longirostrata paying a lot of attention to Odontomachus (or trap-jaw) ants, even when the flies weren’t laying eggs. This called for a closer look.

Entomologist Brian Brown and his colleagues set up cameras in the flies’ habitat and baited the set with injured ants they had collected. Soon enough, the flies came along and descended. What they did next had never before been seen. As you’ll see in the video, it’s brutal, it’s efficient, and it’s totally mesmerizing.

Observing the files’ decapitation technique underscored for Brown the need to keep exploring. “When we consider our lack of knowledge of the other species of the flies here,” he says in the video, “the magnitude of our ignorance is obvious.”

[h/t @BioInFocus]

Header image from YouTube // Natural History Museum of Los Angeles County