Martin Hodson reviews “Entangled Life” by Merlin Sheldrake

Entangled Life. How Fungi Make Our Worlds, Change Our Minds and Shape Our Futures by Merlin Sheldrake (Random House, 2020)

Dr Martin J Hodson

I really like this book. I guess that is partly because it intersects with so many different bits of my own life, and I will mention some of those intersections in my review below. But it is more than that- this is just a great read!

You do not need to have studied fungi before to understand this book, and it is definitely pitched at the intelligent lay person, Radio 4, type level. However, if you have some prior knowledge it will help you appreciate it. I first studied fungi as a botany undergraduate. Fungi have almost always been studied in botany departments. At the time I could not see anything odd about this. Fungi are mostly fairly sedentary, like plants, and just happened to be non-photosynthetic, or so I thought at the time. I did two whole modules on fungi, but in those days we mostly looked at anatomy and taxonomy. Molecular biology was still being invented. But we now know that fungi are actually more closely related to animals than plants.

After a chapter that introduces a lot of the terms, concepts and ideas we begin with a topic close to my heart in more ways than one- truffles! Our honeymoon was in Tuscany, Italy, and it seemed almost every wood had a sign telling people to keep their hands off the tartufi (truffles), and we also found a restaurant whose speciality was truffle pizza. Sheldrake describes his expedition to search for truffles with hunters and their dogs in Northern Italy. The truffles are the underground fruiting bodies of mycorrhizal fungi. Mycorrhizae are the symbiotic associations between roots and fungi- the roots give the fungi sugars and the fungi provide the roots with a massively increased surface area to absorb minerals from the soil. With most mycorrhizal fungi the fruiting bodies are above ground (e.g. mushrooms), and the spores emitted enable the fungi to reproduce. But truffles are underground fruiting bodies and they attract wild boar and other animals by their smell. The animal digs down, gets the truffle, but then spreads its spores over a wide area. Next time I go to Italy I will definitely read the truffle chapter again.

Next lichens, and another fascinating chapter. When I first studied lichens back in the 70s the field was still very much influenced by Simon Schwendener’s “dual hypothesis of lichens”, meaning that a lichen is a symbiosis between a fungus and an alga. That has all changed now, and lichens are seen as very complex entities often with several fungal partners. They are also extremophiles, surviving in the hottest, driest, deserts, but also in the Antarctic, and they have even been able to survive in space, exposed to unfiltered cosmic rays.

Quite a lot of the book concerns mycorrhizal fungi, and not just truffles. Sheldrake spends a lot of time on another concept, the “Wood Wide Web”, which was first coined by David Read in 1997. These are shared mycorrhizal networks that connect trees. These mycelial networks are involved in a lot more than just nutrient uptake. We now know that signals can be sent between trees using these networks. The analogies with neural and computer networks are all too obvious. The whole area has become very much more complex than when I spent a couple of years working on mycorrhizal fungi and aluminium toxicity in spruce back in the 1980’s.

Then “Radical Mycology”. What can fungi do for us? Rather a lot according to Sheldrake. They seem to be able to break down almost any compound that is presented to them, even very difficult substances like lignin and polluting oil. But getting them to do what we want is a bit of an art, and Sheldrake is in his element here.

This is a wonderful book, and I have just skimmed over its surface in this review. My one small criticism is that you can come away from reading it with a rosy glow about fungi. For many years I gave a few lectures on plant pathology, and there is a darker side to fungi, with many very serious plant pathogens which hardly get a mention. Yes, there is quite a lot of information on Ophiocordyceps, a “zombie fungus” which preys on carpenter ants, but this is very much in the context of the changes in ant behaviour that this causes in infected individuals. However, fungi have generally tended to suffer from bad press in the past, so why not a positive book for a change?

Dr Martin J Hodson (JRI Operations Director)

Image: “Truffle collection reserved” from Tuscany by Martin Hodson