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Comment by mannykannot | Hacker News Reader

There are many species of the Entomophthora genus capable of this brain-controlling mechanism [1], and at least this one (Entomophthora muscae) was already known to infect house flies and dung flies [2].

On the one hand, this suggests the genus is capable of adapting to many hosts. On the other, if some Entomophthora species are already endemic in Australia, then presumably the host-jumping risk is already present. Either way, it seems wise to be cautious.

Or maybe E.muscae is already present there? If that is the case, then the question is moot. Furthermore, the fact that it has only recently been seen in fruit flies, despite the latter being extensively studied, suggests it might not be useful in controlling their numbers.

[1] https://en.wikipedia.org/wiki/Entomophthora

[2] https://en.wikipedia.org/wiki/File:Entomophthora_muscae_on_S...

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Yes, there are different cordyceps-like fungi for different species. The thing is, the neurochemistry of even fairly related insects is so different that the fungus would need to make too many adaptations simultaneously to be able to jump between species. It could infect a trillion fruit flies and never jump to dung fly.

https://www.nationalgeographic.com/science/article/parasitic...

As the article you link to is about the question of whether they could jump to humans, I'm not sure it is particularly relevant (there have been many cases of introduced species creating trouble, yet none that I am aware of did so by targeting humans, and if one did, it would presumably be a concern in its natural range as well. The concern here is that if the fungus is introduced somewhere new, it may either attack important endemic insect species immediately, or evolve to do so.)

From the sources I looked at, it seems to be a matter of fact that E.muscae infects multiple hosts. Furthermore, does the fact that the genus Entomophthora contains many fungi which collectively infect many species not suggest that they can, and have, jumped species? It seems implausible that, just within this genus, each of its species independently evolved to target one host, and a species that can do this with one host would seem better positioned, compared to any that do not have this capability at all, to evolve into something targeting a different host (the point is that all these different Entomophthora evolved from something, and it is most likely a single common ancestor with the ability.)

From the article:

> Each zombie-creating fungus species evolved to match a specific insect, so unique strains have little effect on an organism except for the one they evolved to infect. For example, a cordyceps that evolved to infect an ant in Thailand can’t infect a different ant species in Florida.

It is very plausible that the fungus has been around long enough to have evolved with the insects.

The main reason why a cross-species jump is so unlikely for a fungus which induces specific neurological effects is that the mechanism is not intelligent but tuned to the host species’ neurology. The fungus releases specific chemicals at specific times. In the correct host species this results in the desired behavior.

Trying to use the same chemical machinery to control a species which doesn’t share the neurology almost exactly is like trying to run a Windows executable on a Mac.

Importantly, you cannot evolve the machinery bit-by-bit if your life cycle is dependent upon it. Jump to a species with a different neurology would require such a large number of changes simultaneously that it’s just not plausible when anything less would result in a failure to reproduce.

And yet E.muscae infects multiple host species - an empirical fact which falsifies your hypothesis, and is precisely the scenario which raises concerns.

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