‘The Last of Us,’ fruit fly edition | Hacker News Reader

‘The Last of Us,’ fruit fly edition

news.harvard.edu

Article is focused on the study of the parasite, but weirdly didn't touch on the potential hobby / commercial use of a fungus that attacks fruit fly.

Here in Australia we have two major fruit fly pests - the Mediterranean (introduced) and the Queensland (native).

Pesticides are either very nasty or very expensive (or both). Effective netting is extremely difficult, and very expensive.

There's been some promising progress on using fungus to try to control two major honey industry pests - small hive beetle and varroa destructor. I'm really looking forward to deploy-and-mostly-forget bio controls for pests that we can deploy at landmass level.

eg. https://www.science.org/content/article/scientists-evolve-fu... (Varroa)

https://agrifutures.com.au/wp-content/uploads/publications/0... (small hive beetle)

The pest control you’re talking about seems really dangerous. Disrupting an entire species and consequently the food chain + giving zombie fungus a lot of biomass to feed on and evolve…

sounds like a movie plot haha

> Disrupting an entire species and consequently the food chain

One of the types was introduced in a not very distant past, so it doesn't seem like a bigger disruption than what we've already done.

You should read up on stoat introduction to New Zealand.

Pretty sure viraptor would know about that. Also rabbits and myxamatosis and later rabbit calicivirus in both Australia and NZ, and various other well-intended biological "control" introductions that went pear shaped. Cane toads, for instance. Miscellaneous parasitic wasps.

Luckily this zombie fungus is very precise in what species it targets, and a fungus specialized in fruit fly would find it borderline impossible to jump even to other kinds of flies.

Right at this moment, yes, but after infecting a billion fruit flies, evolution would have given it a billion chances to jump species. Seems enormously irresponsible to release a fungus like this.

And fruit flies are often used, due to their short life cycle, for genetic experiments. They evolve fast.

Case in point, they are now known to metabolize ddt, and I think this was discovered 20 years ago.

And any fungus will try to evolve with them... and theoretically the local species have no defense?

It's surprisingly difficult to get an estimate on the fruit fly population of California, or even just an average 'per unit area' figure.

Anyway, this fungus is already endemic in California, and I believe California has a major problem with this pest. I'd be surprised if there weren't at least a billion fruit flies active in California mid-summer.

As I said in a sibling comment, let's do some safety validation & deployment testing, but also let's not forget this is already out there.

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...

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.

And the precursor to covid was only found in bats… until researchers decided to do some upgrades and develop it for use

The pest control I'm talking about 'releasing' is literally already in Carolyn's back yard - Carolyn being the post-doc researcher subject of TFA, based in California, USA.

So, yeah, it's really dangerous, but probably only for these species of fruit fly.

I'm not suggesting we (Australia) would not validate it against other related species, including native fruit flies, and then do a risk / benefit analysis based on those findings.

Regular inoculation of trap bait/fruit, regional dispersal schedules, etc may be all that's required to knock pest population numbers down periodically.

> hobby

Hobby?

Let him who never wanted to remote control a fruit fly cast the first stone...

https://newatlas.com/science/fly-brains-hack-remote-controll...

Oh, I missed a word - should have written 'potential hobby / commercial farmers' (or orchardists, fruit growers, etc).

Hehe, my imagination went to some amusingly dark places.

Finally we can create a cyberpunk Beelzebub!

> the Mediterranean (introduced)

But this time, nothing will go wrong.

> Queensland

> I'm really looking forward to deploy-and-mostly-forget bio controls for pests that we can deploy at landmass level.

Did we just forget how Queensland already tried with with Cane Toads and it went horribly? https://en.wikipedia.org/wiki/Cane_toads_in_Australia

But from the synopsis section of that wikipedia page, there is an example of biological control going well in australia:

https://en.wikipedia.org/wiki/Cactoblastis_cactorum

Perhaps it isn't a black and white issue after all

In the same way that Russian roulette isn’t a black and white issue?

And don’t forget myxomatosis!

Please stop developing bioweapons. We just went through one and now you want to release one on purpose which can hide in brains? We can’t even defeat athletes foot and that’s only on the skin surface.

Toxoplasmosis causes infected rats to change their behavior. They stop fearing cats, and are thus at greatly enhanced risk of being eaten. This is part of the parasite's lifecycle.

Toxo also infects humans and is known to increase risk-taking behaviors:

https://blogs.biomedcentral.com/bugbitten/2018/09/11/mind-al...

Agreed that Toxoplasmosis is interesting! Just wanted to point out that Toxoplasma Gondii is a protozoan and not a fungus.

Rabies prevents swallowing and induces hydrophobia, increasing the chance of transmission on biting, and paranoia and delirium, increasing the chance of biting.

>They stop fearing cats, and are thus at greatly enhanced risk of being eaten.

Recent studies have shown that it doesn’t reduce their fear of cats, it reduces their fear in general. Manipulating the mammalian brain, other than in broad strokes, is extremely difficult.

> Toxo also infects humans and is known to increase risk-taking behaviors.

Not "known", more like "suspected". Evidence is rather weak at the moment, with studies that contradict each others, I think it is safer to say that we don't know.

There is also a growing body of evidence that Toxoplasmas is linked to schizophrenia [0]. HN discussion [1]

[0]: https://www.sciencedirect.com/science/article/pii/S014976342...

[1]: https://news.ycombinator.com/item?id=34021789

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