There are many poisonous fungi in nature. For example Amanita Phalloides. What reasons could a fungus need poison for? Some species, like venomous snakes, use poison to kill other species as prey. But what about fungi? I can't think of any purpose for poison in fungi. If poison has no real function in fungi shouldn't evolution get rid of it?

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    $\begingroup$ I just want to make the general point that poisons do not have to be adaptive. It is entirely possible for metabolites of one organism (e.g. fungi) to be poisonous for another organism if ingested (e.g. humans), without having been selected for because of its poisonous effect. $\endgroup$ Aug 14, 2013 at 12:02
  • $\begingroup$ @fileunderwater that makes sense :) $\endgroup$ Aug 15, 2013 at 11:54

1 Answer 1


The same reason some plants are poisonous: to stop animals from eating them.

The visible part of the fungus is called, rather misleadingly, the fruiting body. It exists to produce and spread spores and thus produce the next fungal generation. Getting eaten, rather obviously, inhibits its ability to do this. Being poisonous discourages animals from eating the fruiting body and thus permits it to complete its life cycle.

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    $\begingroup$ Some mycotoxins are designed to kill/weaken the host in the case of pathogenic fungi, and some others (penicillin) are designed to kill off competitors for food. $\endgroup$
    – Resonating
    Aug 14, 2013 at 20:10
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    $\begingroup$ Sorry, but it is often claimed the contrary: that some mushrooms have bright colors to ATTRACT animals so that they eat them to spread spores. $\endgroup$
    – Anixx
    Dec 1, 2014 at 11:01
  • $\begingroup$ @Anixx: I'm not aware of such a claim and would be interested in a source? Even if it is true I am quite certain that those mushrooms will not be poisonous. $\endgroup$ Dec 1, 2014 at 11:47
  • $\begingroup$ biology.stackexchange.com/questions/20333/… $\endgroup$
    – Anixx
    Dec 1, 2014 at 13:02
  • $\begingroup$ @Anixx Fungi have come up with many weird and wonderful ways of spreading spores, from being eaten as you say to mind altering neurotoxins! You're right to bring this up. But for the general nature of the question I thing a general answer is best fitting else the answer would risk going off topic perhaps... $\endgroup$
    – James
    Jan 10, 2015 at 2:29

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