A fungus replaces a cicada's abdomen, and the cicada keeps flying

Massospora consumes the rear of an adult cicada and turns it into a mass of spores. The insect, abdomen gone, continues to fly and to seek mates, and in doing so spreads the fungus.

Periodical cicadas spend years underground and a few weeks in the air. Massospora meets them in the air. The infection destroys the abdominal segments and replaces them with a plug of spores, chalky and exposed. Observers have known since the nineteenth century that these cicadas do not simply drop. They fly, they approach other cicadas, and the contact moves spores onto the next host, including by the attempts at mating that a cicada with that injury has no reason, of its own, to continue. The behaviour is the old fact. It is grotesque and it is documented across emergences.

In 2019 a chemical survey found plant-like alkaloids in the infected animals: cathinone in one Massospora species, psilocybin in another. Those are psychoactive compounds, and it is tempting to say the fungus drugs its host into the last flight. The temptation is ahead of the proof. The compounds are there. That they cause the hyperactivity is a hypothesis the paper raised, not an experiment it closed. The flight without the abdomen does not need the hypothesis. It was already true, and it is quite enough.