On a practical note, the world would be covered in dead wood if fungi were not its most efficient consumers, he said.
Hosting the conversation was astrophysicist Neil deGrasse Tyson, PhD, an author and educator who emphasizes the importance of science to the public.
“When I looked at the tree of life, what I learned was that the common ancestor between mushrooms and all animal life split later than that common ancestor split from green plants,” Tyson said. “That blew my mind because that means that mushrooms and animals are more closely related to each other than they are to green plants.”
Popular culture is most fascinated by the bizarre ability of Cordyceps fungi to turn ants into automatons, robotically climbing plants and distributing spores. Found in tropical forests, Ophiocordyceps unilateralis somehow evolved this sinister technique and is able to create ant “zombies” — as they are inevitably described in the popular press.
“The degree of precision is remarkable,” Sheldrake said. “You have, for example, a carpenter ant. Cordyceps fungus will grow into the ant, into its body, its legs, through its cavities. It doesn’t grow into the brain, but it produces in the ant an irresistible urge to climb upwards, overriding the normal instinct of the ant to stay close to the ground.”
In a syndrome known as “summit disease,” the ant climbs a plant and attaches itself at an ideal height for dispensing spores from, say, the bottom of a leaf.
“About 25 centimeters off the floor of the forest,” Sheldrake said, “the fungus kills the ant. It grows a stalk out of the ant’s head, which rains down spores.”
The popular video game series and television show adaptation “The Last of Us” extended this zombie premise in a post-apocalyptic age, imagining an explosive expansion of mutated Cordyceps fungus that invades human bodies.
“The TV show has definitely increased awareness,” says Megan Lyman, MD, a medical officer in the mycotic disease division at the Centers for Disease Control and Prevention.
“We want to take advantage of this [public interest] to bring awareness to fungal diseases. People don’t realize how important fungal diseases are. We’re glad to get press, but we don’t want people to think that these diseases are going to turn them into zombies.”
Climate Change and Pandemics
However, there is real concern and emerging research that fungi eventually could pose a pandemic threat as the result of global warming.
Neil Vora, MD, a pandemic prevention fellow at Conservation International in New York City, recently wrote a commentary saying he watched “The Last of Us” and was struck by its beginning.
“A 1960s talk show host asks two epidemiologists what keeps them up at night. ‘Fungus,’ one replies,” Vora noted.3
“Scientists like me worry that climate change and ecosystem destruction may be creating opportunities for fungal pathogens to grow more infectious, spread over larger distances, and reach more people,” he said.
The body heat in humans thwarts spore growth, but researchers have specifically referred to the rapid rise of Candida auris
as an example of climate change accelerating the rise of infectious diseases. In this scenario, heat-tolerant fungi eventually could be selected out as the climate warms, possibly creating strains that can overcome the endothermal defenses of the immune system.
“The nearly simultaneous emergence of Candida auris on three continents, an event proposed to result from global warming, has raised the specter that increased warmth by itself will trigger adaptations on certain microbes to make them pathogenic for humans,” Arturo Casadevall, MD, PhD, a microbiologist at Johns Hopkins, warned in a viewpoint piece.4
Perhaps the increased awareness in academia, public health, clinical settings, and pop culture will elevate fungi to global attention and action. As it stands, we are unprepared, Vora concluded in his commentary.
“No fungal vaccines exist, diagnosis is complicated and costly, and there are not enough drugs to combat fungi,” he noted. “Unless governments fund research to better address fungal disease and reverse the environmental factors that fuel their emergence, we will remain vulnerable.”
Sheldrake said fungi essentially could take forms for the good or ill of humanity as they adapt to climate change.
“Fungi are startlingly ingenious opportunists, and as things change, they will be able to move into new niches,” he said. “Sometimes that will be good for us, and sometimes less good.”
- Tyson ND. Magic mushrooms, fungi, and the mysterious kingdom with Merlin Sheldrake - Cosmic Queries. StarTalk with Neil deGrasse Tyson. July 29, 2021. https://www.youtube.com/watch?v=59JisQXUeTg
- Sheldrake M. Entangled Life: How Fungi Make Our Worlds, Change Our Minds and Shape Our Futures. Random House; 2020.
- Vora N. ‘The Last of Us’ is right. Our warming planet is a petri dish. The New York Times. Published April 2, 2023. https://www.nytimes.com/2023/04/02/opinion/the-last-of-us-fungus-climate-change.html
- Casadevall A. Climate change brings the specter of new infectious diseases. J Clin Invest 2020;130:553-555.