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A parasitic fungus is turning ants into “zombies” around the world.
The fungus is like something out of a horror movie: the organism hijacks its ant host’s body and brain, directing it to leave its nest and climb a nearby tree.
There, the infected ant clamps its jaws around a leaf dangling above the forest floor and dies within days while the fungus digests it. The fungus breaks through its host’s body and then sends down a shower of spores to infect the next generation of ant prey.
Scientifically classified in the genus Ophiocordyceps, the more than two dozen species of zombie ant agaric populate the globe, including Florida, Brazil and Japan; Scientists suspect that each of the dozens of ant species affected has its own specialized strain of Ophiocordyceps.
So far, scientists have figured out the molecular mechanism of the parasitic interaction between fungus and ant, which forms the basis of behavioral manipulation and Study 2020. However, little is known about exactly how these parasites proceed systematically.
Now scientists have found that the ant-attacking fungus is infected with its own fungal parasites, which could help keep ant zombification at bay, according to a new study.
Dr. João Araújo, Associate Curator of Mycology at the New York Botanical Garden, has been wandering tropical forests in search of zombie ants for more than a decade. Over the years, he kept noticing something odd: a blurry white fungus growing on the zombie ant agaric.
Other scientists have noticed the mysterious fungus for decades, but Araújo and his colleagues decided to become the first scientists to look at the matter systematically by focusing on a strain of Florida zombie ants. The researchers described the physical structure of the fungi growing on the zombie ant agaric and sequenced their DNA a study published Nov. 9 in the journal Personia.
The team discovered two new genera of fungi that were previously unknown to science.
“We found that there were two distinct fungal lineages, novel fungal lineages, that infected a species of zombie ant agaric in Florida,” said Araújo, the study’s lead author.
Each of the two newly discovered fungi belongs to its own genus. One of the new fungi, Niveomyces coronatus, is responsible for the zombie ant agaric’s fuzzy white coating — part of its name (‘niveo’) comes from the Latin for ‘snowy’. The second new fungus, Torrubiellomyces zombiae, is harder to spot: the small black lumps “look like fleas,” according to Araújo.
The fungi that attack the zombie ant agaric do not zombify their host themselves, but feed on its tissues and appear to damage them. “Every time we see these new genera that we’ve described growing on the fungus, the fungus looks pretty battered, really consumed by this other fungus,” Araújo said.
“In some cases, it first castrates Ophiocordyceps (the zombie-producing fungus) so it can’t shoot the spores anymore, and then it grows and then consumes the whole fungus.” Because Niveomyces and Torrubiellomyces are so new to science, it’s not clear yet how much they affect zombie ant fungal populations overall.
These new genera are the first parasites officially described as infecting the zombie ant fungus, but researchers suspect there may be others out there. “I think it’s more common than we think. Parasitism is a super lucrative lifestyle,” said lead study author Dr. Charissa de Bekker, Assistant Professor at Utrecht University in the Netherlands. “It might be the most dominant lifestyle on the planet.”
In addition, parasites in general and parasitic fungi in particular have hardly been researched. “The fact that we had to call up two new genera shows you how little we know about this part of the fungal tree of life,” de Bekker said.
By deepening our understanding of the zombie ant fungus, the new research could have applications beyond studying fungi, said Dr. Carolyn Elya, postdoctoral researcher in organismal and evolutionary biology at Harvard University. She was not involved in the study.
“Ophiocordyceps has essentially evolved into a skilled neuroscientist. It knows exactly which buttons to push and how to get the ant to do what it wants,” she said. “By examining how to solve this problem, we can gain insight into our broader goal of trying to understand how brains work or produce behavior.”