RE: Mushrooms can have 4,000+ different sexes
Heh, I'm now a bit more confused than before reading this, though maybe those two beers I drank earlier might have something to do with it. However, 4000+ sexes is weird.
I have a question though. We now know that mushrooms make symbiotic bonds with plants like trees, flora. But is there similar symbiosis between fungi and fauna? I think some yeasts might be able to live in the digestive tracts of animals, and also know of leaf cutter ants which farm a fungus, but is it really symbiosis in either case? And if not, can there be one?
I'm asking, because when I was younger I used to read a lot of science fiction, and in one of the books there was described a symbiosis between a mushroom and human. The mushroom could think, and forming a symbiotic bond with a human they'd form an ultimate mind of sorts. (I don't remember whose book it was, nor the title. But the book left me a strong impression anyhow.) I know those kinds of symbiosis are kind of far fetched, but it was definitely something that got me thinking; What if?
Thanks for a long and good comment! To answer this I first need to have some definition for the term symbiosis. The problem with this term is that there are lots of different definitions, but for my ecology studies we have always used something along the lines of "any persistent interaction between individuals of different species", which I think is pretty commonly used in ecology. This includes mutualistic interactions (positive for both species), commensalistic (positive for one species, and does not affect the other species), and parasitic (positive for one species, negative for the other). The interaction has to be over time, so a random encounter of two species does not count as symbiosis.
With this broad term we can definitely conclude that there is lots of symbiosis between fungi and animals. I'm not very familiar with these types of fungi, but there are for sure lots of fungi that uses humans and other animals as hosts. This is a parasitic symbiosis. There are also animals which use fungi to help digest their food, so this is a good example of mutualism.
The problem with using this broad term of symbiosis is that it is everywhere. With this definition even human-dog relationships are mutualistic symbiosis, where the human gains increased happiness / increased security or whatever you use your dog for, while the dog gains food and shelter. But with this definition, all the examples you made are a form of symbiosis.
Anyway, over to the sci-fi question you have. We don't really have any fungi that does what you described, but I suppose it could theoretically be possible. There are other parasites that can alter the behavior and personality of their hosts, but for this part we are talking about a parasitic symbiosis, not a mutualistic one. A good example is the protozoan Toxoplasma gondii, which uses cats at their main host. However, all other warm-blooded animals can be infected, and infected rodents will be altered into being more likely to be preyed upon by a cat. So in this example the parasite makes the host get killed to it can continue its life-cycle. Some scientists also think humans will have a personality change when they are infected this with parasite, and there is even a term for it: "Crazy cat-lady syndrome". Note that this is a protozoan and not a fungi, and I'm not even sure if fungi can do this, since I'm not all that familiar with infectious or single-celled fungi.
Great read on the article itself and your comment.
Thank you!