Being a mushroom enthusiast, I was very pleased to receive, for my birthday last year, the book Entangled Life, written by Merlin Sheldrake.
I normally take my time to read a book, but I found this one so engaging that I devoured it. Though not as literally as the author did when he ate oyster mushrooms that he grew on a printed copy of his book (there is a YouTube video of it at the bottom of this page).
This book taught me a lot of things I didn't know, and these are three of the most remarkable facts that I learned while reading it.
Brainless moulds can solve labyrinths
Neurospora crassa uses a natural algorithm to decide where to move in a micro-confined network, e.g. a labyrinth . The algorithm used by these fungi has been shown to even outperform some mathematical algorithms . Similarly, the slime mould Physarum polycephalum can locate food and form a network of links that shows remarkable similarity to public transport links designed by engineers to connect cities on a rail network, hence following the most efficient route possible.
There is a video, here, that shows how slime moulds recreated a similar pattern as the rail network existing around Tokyo when guided by oats (a source of nutrients for the moulds) strategically placed on a Petri dish to resemble the location of Japanese cities around the capital.
Truffle’s aroma is essential for its survival
Truffle fruiting bodies, which are their edible elements, are part of a microbial community (microbiome). This includes bacteria, yeasts and, in some cases, even other filamentous fungi . The variable composition of the truffle microbiome during its life cycle may affect the bouquet of volatiles that it makes. The volatiles, between 10 and 20 molecules for black truffles and more than 15 compounds for the white truffle, are made by a combination of the truffles themselves and the other microorganisms that live with them. What is even more remarkable is that the truffle’s powerful aroma is believed to be the result of an evolutionary process that allows them to be located by mammals and rodents who then eat them. This ultimately promotes spore dispersal and colonisation of new environments, a process that would otherwise be difficult to achieve for an organism that lives underground.
The ‘drunken monkey’ hypothesis
This is tangentially related to fungi, specifically to the yeasts that naturally ferment sugars in ripe and overripe fruit. Ethanol is produced as part of this fermentation and accumulated in the fruit. The drunken monkey hypothesis, proposed by Robert Dudley, argues that present-day humans are attracted to alcohol because our primate ancestors used to follow the scent of alcohol to locate ripe fruit fallen on the ground and consume it as a source of food. Support to this hypothesis comes from evidence that a mutation of the alcohol dehydrogenase gene, ADH4, occurred in primates about ten million years ago and provided them with a variant of the enzyme that is forty times more efficient. This mutation gave our ancestors the ability to break down ethanol and use it as a source of energy, and it is believed to have happened around about the time when primates left trees and started spending more time on the ground. In other terms, our attraction to alcohol has roots that go back a very long time, way before we started fermenting grain and fruit juices.