The Curious Connection Between Brain-Eating Flies And Chocolate

A large leaf-cutter ant has just cut a piece of fresh, new leaf from a cacao tree in Brazil.

- Pat Betteley

Hovering above, a humpbacked fly stalks the ant. The ant’s jaws are out of action while it carries the leaf, so the worker ant teams up with a smaller “minor worker.” The worker rides atop the cut leaf like a surfboard, acting as a bodyguard to defend its comrade from fly attacks. Sensing the perfect moment, the fly dive-bombs the ant. It pierces its hide and lays an egg inside its body. When the egg hatches, the larva travels to the ant’s head and begins feeding on the insect’s body fluid, muscle, and nervous system. After the larva has eaten the entire brain, the “zombie” ant is left to wander aimlessly for weeks until (and sometimes after) its head falls off. The larva inside the bodiless head becomes a pupa, and finally climbs out as a fresh adult. Talk about a mindblowing life cycle!

This ant-decapitating brain-eater belongs to the insect family called phorid flies, which includes 3,500 species. Most are scavengers, predators, and parasitoids. A parasitoid is an insect whose larvae feed and grow within or on bodies of other arthropods (insects, spiders, crustaceans),