The Wonders of Fungi

Last 5th of December (2023), in the presence of some pumpkin cake and inevitably some white wine, Anne brought to Tessellate the book Entangled Life by British mycologist Merlin Sheldrake. The book is an attempt to make the lives and forms fungi take more accessible to the general public. The fungi “kingdom” is usually reduced to mushrooms, their fruiting bodies. Those are the parts of fungi we usually encounter more often in our daily lives (here in Germany you just need to go downtown to the nearest bar to hear about the success of Schnitzel mit Champignonsauce). However, the fungi kingdom, while only constituting about 2% of the biomass of the planet, has been critical to shaping all sorts of life on Earth. Particularly by means of entangling with it, the idea around which the book gravitates. From all the topics discussed in our session, I choose to write about 2 of them that allow for further debate. Here we go:

Fungi entangling with the behavior of animals:

1. Truffles and their latest successful trick (I could not help but play Dire Straits – Your Latest Trick). Truffles such as the delicacy Tuber magnatum are the fruiting bodies of mycorrhizal fungi. These fungi live underneath the soil buried up to 20 cm deep. That poses a problem for how spores usually work: by being carried away by streams of wind. Their trick is to emit fragrant and exquisite odors—after diffusing through the packed soil and reaching the olfactory receptors of animals (such as wild boars), these perfumes lure the animals into finding the source of such a penetrating smell. Motivating them to dig the soil and eat the truffles, thereby spreading the spores. This is just one example of how fungi, sessile creatures, can lure animals into working for them with their exquisite chemistry. This example levels up when we take into account how human behavior is affected by truffles like Tuber magnatum. Sheldrake describes how the knowledge of where truffles live are deep family secrets, how life-threatening it can be trying to steal these secrets, and how many thousands of euros people are willing to pay to have truffles freshly grated on top of their food. By the way, these truffles cannot yet be cultivated successfully due to our poor understanding of their ecosystems.

2. Psilocybin: from ants to humans. Psilocybin is a molecule with great affinity for the serotonin receptors in many parts of our brain. As a consequence, when taken in sufficient amounts, it alters neurotransmission and makes people trip. People under the influence of this substance usually report these trips as being amongst the most insightful experiences of their lives. Although given our limited current knowledge we can only draw broad strokes, there is evidence that, among other effects, psilocybin tends to act as a break on the default mode network and goal-directed action and facilitates more lateralized synaptic connections. These folks typically report being more focused in the here and now as well as seeing things from a different perspective. Now, the fact that a substance synthesized by fungi can have such profound effects on human mental states is quite remarkable. So much so that it has made people think that eating magic mushrooms (or psilocybin-containing mushrooms) is what boosted the intellect of Homo sapiens in comparison to other hominids. That is the stoned-ape theory by Terence McKenna, which cannot really be proven or disproven but which has not been taken seriously by the scientific community due to its lack of referencing. Psilocybin, however, has been present for as many as 75 million years, which suggests that it has conferred fungi with an advantage since early on. Latest hints suggest that it could have been a tool to manipulate behavior of ants and other fungal competitors. The how remains a mystery. 

Fungi entangling with other organisms: 

1. Lichens are truly remarkable beings. They are formed by at least one mycobiont (a fungus), whose part of the deal is to construct most of the organism’s body, and at least one photobiont, whose part is to provide the organism with energy from photosynthesis. Now, lichens sometimes have more than one fungi and more than one photobiont, the tree of possibilities being almost unimaginable. As a consequence of their promiscuity, they constitute utterly specialized and successful organisms. They are known for their extremophile abilities, for example withstanding enormous amounts of radiation when launched into space. They challenge the definition of an individual because they are extremely fluid in how they form new alliances and also stop them when conditions are not appropriate anymore. Recently, David Griffiths wrote an article about Queer theory for Lichens worth reading, in which he argues for a more general fluid perspective to understand lichens, life, as well as gender identity. 

2. The Wood Wide Web (WWW). When walking in a forest one might not be aware of the incredibly complex network that lies beneath one’s feet. Plants are heavily interconnected with each other by the grace of mycorrhizal fungi forming what is known as the WWW. Plants such as Monotropa are fully dependent on mycorrhizal networks, so much so that they have given up photosynthesis and display a range of unusual fascinating colors.  This means that they must be plugged into a wealthy WWW in order to obtain the necessary carbon building blocks needed to sustain plant life. Again, the WWW challenges the concept of individuals, at least as long as we include independence in its definition. Who is the organism… the network, or the individual elements that form it? How can we discretize life units, and does this even help us? The difference is in the eye of the beholder. In any case, our inability to understand complex ecosystems like the ones formed by the WWW explains why we still are unable to farm truffles. One last very cool remark about the function of these mycorrhizal fungi in the WWW: they do not only fulfill a passive hardware function connecting the elements of the network, but they are also known to be key functional players. They modulate nutrient transfer and play a central role in establishing a healthy equilibrium and sustaining the activity of all individuals upon which the network depends.  They govern—in the most political sense—the network in the interest of themselves.

We closed the session by highlighting that Merlin had done a good job making the (wonderful) world of fungi more accessible to a general audience with well-referenced studies and interesting facts. As for the style, the book is written from a traditional biologist perspective, having a well-intentioned tone while successfully conveying his amusement of fungi. Some of us felt that in order to find causal understandings of systems as complex as the ones fungi take part in, the field of biology really needs to update its tools. Its methods need to shift from being mostly observational/comparative to more quantitative ones. Many of the studies outlined in the book as well as the subsequent conclusions would benefit from more modeling. Highlighting once again the need for more horizontal skill transfer among scientists and entangling—or tessellating, you name it ;)—science altogether.