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Friday, April 8, 2022

Gaia in Red Tooth and Claw: do Ants Sacrifice Themselves to the Fungus God?

A Carpenter Ant attacked by Ophiocordyceps unilateralis. The fungus is reproducing by sprouting a fruiting body out of the ant's body. It is cruel and horrible, and yet fascinating. What's happening, exactly? Is this a sacrifice to the fungus God?

There are things in nature that are far from being the happy world of Disney's cartoons. I stumbled recently into the story of the "Zombie Fungus" and of how it captures ants, devouring them from inside. It is a story that has been known for a long time, discovered in 1859 by that Alfred Russel Wallace, who was the co-discoverer with Darwin of evolution by natural selection.

It is a classic example of Nature "in red tooth and claw" as Alfred Tennyson defined it in 1830. An exquisitely evil story:
"When the fungus infects a carpenter ant, it grows through the insect’s body, draining it of nutrients and hijacking its mind. Over the course of a week, it compels the ant to leave the safety of its nest and ascend a nearby plant stem. It stops the ant at a height of 25 centimeters—a zone with precisely the right temperature and humidity for the fungus to grow. It forces the ant to permanently lock its mandibles around a leaf. Eventually, it sends a long stalk through the ant’s head, growing into a bulbous capsule full of spores. And because the ant typically climbs a leaf that overhangs its colony’s foraging trails, the fungal spores rain down onto its sisters below, zombifying them in turn.

"So what we have here is a hostile takeover of a uniquely malevolent kind. Enemy forces invading a host’s body and using that body like a walkie-talkie to communicate with each other and influence the brain from afar. Hughes thinks the fungus might also exert more direct control over the ant’s muscles, literally controlling them “as a puppeteer controls as a marionette doll.”

Note, indeed, the cruelty of the procedure: the fungus does not touch the ant's brain. It only cuts all the communications the brain has with the muscles of the ant's body. We may imagine the poor creature watching in horror as its body is snatched away from its control and led to do things that no sane ant would ever do. The ultimate horror? Surely it has been the source of inspiration for many horror movies. So, is Gaia really such a bitch?

The answer, as usual, is nuanced. Gaia is not a Goddess -- she is a Daimona (Δαίμονα), a servant of the Almighty, just like all of us. She just happens to be the highest-ranking daimon ("holobiont," using a more modern term) on Earth. Holobionts are not necessarily cruel, but they are not necessarily benevolent and merciful, either.  

But by seeing the ant being devoured by the fungus as cruel, we are making the same mistake that Richard Dawkins made when he tried to explain in evolutionary terms why trees are as tall as they are. Trees, definitely, are not male primates -- as Dawkins is. And ants, despite much fictional characterization, are not minimalist versions of human factory workers. Of course, we shall never be able to know what an ant thinks, but we can say that it is not an "organism" in the same sense as a human being. An ant is not a creature for which we can define a genetic individuality. It is only an expression of the genotype of the ant colony it is part of. It is no more an individual than a red blood cell in our body is. For an ant colony, losing a few ants is nothing worse than for us losing a few drops of blood.  

If the ant is not an organism, then it has no obvious interest to develop a form of defense against fungal attacks. As is a sterile female and it wouldn't be able to pass this information to its descendants. It is the anthill that evolves, not single ants. Only the anthill can be seen as a full-fledged "organism" -- although it also has elements of the holobionts.

So, the term "zombification" is wrong in many respects. Mainly because what we are seeing is not a fungus-ant interaction. It is a fungus-anthill interaction. Only the anthill could develop forms of resistance against this kind of attack and pass them to its descendants. But, apparently, that was never a priority. Reports Merlin Sheldrake in his book "Entangled Life" that there are traces of this fungus affecting ants already more than 45 million years ago. If there had been an advantage for the anthill in evolving a defense against this fungus, there was plenty of time to do that.  

Indeed, when the zombie fungus attacks an ant, that's not an attack. It is a form of communication. In other words, it is not parasitism, it is symbiosis, probably of the mutualistic kind. The fungus and the anthill can be seen as a holobiont in themselves. The fungus communicates with the anthill by infecting a few ants and using them to reproduce itself. The anthill doesn't care about giving the fungus a few of its ants. It does that, surely, in exchange for useful information. The anthill-fungus interaction is much more complex and wide-ranging than the formation of the fruit body, the only thing we can observe from our macroscopic and remote viewpoint. We can only say that it is a conversation that must be significant for both organisms. Otherwise, they wouldn't have been engaged in it for 45 million years. Good holobionts form long-lasting relationships!

Yet, there remains a dark fascination in the event we can witness. A single ant moves away from the colony to reach a high place, from where she (a female worker), gives herself completely to the fungus in a sort of apotheosis that (excuse me for the blasphemy) reminds the Christian myth of the sacrifice on the cross

Think for a moment about that, a "sacrifice" means to separate something from the human sphere to transfer it to the divine sphere. It is a form of communication with the Gods, the only one that was left to humans once the Gods stopped speaking to them from inside their minds (at least according to Julian Jaynes). Do ants see this behavior as a sacrifice to the Fungus God? Who knows? As I said, we can't know what an ant thinks, but of one thing we can be sure: the macrocosm reflects the microcosm and the holobiont universe is fractal. So, we should not be surprised if we see a reflection of our own deep thoughts on such as small scale as an anthill. 

The ant sacrifice has a further element relevant for us. Unlike ants, we are organisms interacting on an individual basis with the microscopic world of fungi, bacteria, archaea, and viruses. We are not normally invaded by hordes of hungry creatures wanting to zombify us because of tens of millions of years of individual conversations that our ancestors engaged in with the creatures that surrounded them. Our body knows how to deal with them. That is, unless we chose to stop communicating with them by masking, disinfecting, and other useless rituals. Only if we continue with this unnatural behavior, do we risk seeing mushrooms sprouting from the back of our heads. (*)

And, in the end, Gaia knows best. 

 (*) which, by the way, may be exactly what we are facing with the current attack by the fungus called "Candida Auris." It is a battle that we cannot win as long as we don't recognize that the ecosystem is not our enemy.  


  1. Wow, this is wonderful, Ugo! I just read it aloud to Connie and we both loved it!!

  2. Nature is the sort of thing for which even the term "neutral" is inappropriate.