Zombies are real... amongst Ants anyway...

[Solauren]

Please don't make a species jump to humans...

In a bizarre parasitic death sentence, a fungus turns carpenter ants into the walking dead and gets them to die in a spot that's perfect for the fungus to grow and reproduce.

Scientists have no clue how the fungus takes control of the brains of ants so effectively. But a new study in the September issue of the American Naturalist reveals an incredible set of strategies that ensue.

The carpenter ants nest high in the canopy of a forest in Thailand, and they trek to the forest floor to forage. The fungus, Ophiocordyceps unilateralis, prefers to end up on the undersides leaves sprouting from the northwest side of plants that grow on the forest floor, the new study showed. That's where temperature, humidity and sunlight are ideal for the fungus to grow and reproduce and infect more ants.

Once infected by the fungus, an ant is compelled to climb down from the canopy to the low leaves, where it clamps down with its mandibles just before it dies.

"The fungus accurately manipulates the infected ants into dying where the parasite prefers to be, by making the ants travel a long way during the last hours of their lives," said study leader David P. Hughes of Harvard University.

After the ant dies, the fungus continues to grow inside it. By dissecting victims, Hughes and colleagues found that the parasite converts the ant's innards into sugars that help the fungus grow. But it leaves the muscles controlling the mandibles intact to make sure the ant keeps its death grip on the leaf.

The fungus also preserves the ant's outer shell, growing into cracks and crevices to reinforce weak spots, thereby fashioning a protective coating that keeps microbes and other fungi out.

"The fungus has evolved a suite of novel strategies to retain possession of its precious resource," Hughes said.

After a week or two, spores from the fungus fall to the forest floor, where other ants can be infected.

Making nests in the forest canopy might be an evolved ant strategy to avoid infection, Hughes figures. The ants also seem to avoid foraging under infected areas. This too might be an adaptive strategy to avoid infection, but more study is needed to confirm it, he said.

How the fungus controls ant behavior remains unknown. "That is another research area we are actively pursuing right now," Hughes said.

[Stuart]

The implications of that can be quite chilling if we find out how that fungus does it. I can think of several ways it could be weaponized.

[Isolder74]

Cordyceps Fungus. This type of thing is very common in the rain forest environment and it even seems to have a variety for every insect species in the forest.

[j.eller]

I read about this a while back in National Geographic and it creeped me the hell out. Got to admire it as a propagation mechanism though.

And it isn't just ants either...
http://www.livescience.com/animals/0704 ... urine.html

[Lagmonster]

The implications of that can be quite chilling if we find out how that fungus does it. I can think of several ways it could be weaponized.

Not really; without getting complicated about it, I'd expect that while the principle isn't too complex, you'd have to develop an entirely new organism to do what you might want, and you'd find that creating something that caused a handicap or debilitating illness, or simply something outright lethal, might just be easier.

[The Vortex Empire]

I've known about this stuff for years, it's very interesting. Though it seems to me that weaponizing it would be exceedingly difficult, as a human brain is just a tad more complex than an ant brain.

Would it be unreasonable to launch an effort to exterminate that fungus to prevent anyone from ever figuring out how to use the stuff against people?

Would it be unreasonable to nuke huge swaths of the planet and wipe out tens of thousands of species? Yes?

[Solauren]

I'd be more concerned about finding a way to duplicate the baseline behaviour of the Fungus (taking over a nervous system) using technology.

Once you do that, you can effectively make 'slave chips'.

[Dominus Atheos]

This is hardly the only thing that can take control of ants and turn them into zombies.

Ants eat those mucus balls (obviously the mucus contains also certain pheromones that makes it highly attractive to ants) and then are afflicted by the cercaries. The cercaries grow in the ants' abdomen (terminal body part) and then one of them moves into the head. There they afflict the ant's nervous system and cause a change of behaviour, that makes Bernard Werber call them "zombie ants". The ants now, very untypically, climb up plant stems and attach themselves with their mandibles to exposed positions such as leaves.

Grazing mammals, such as sheep or goats, eat the plants together with the ants and then infect themselves with the lesser liver fluke. Inside this terminal host the cercaries change into the fluke's adult stage which reproduces sexually and then lays eggs that are excreted by the mammal - the generation cycle is closed when the next snail eats the eggs.

[Samuel]

The implications of that can be quite chilling if we find out how that fungus does it. I can think of several ways it could be weaponized.

I don't think the method the fungus uses can be applied to human beings. Plus we already can have diseases that screw with the human mind- just engineer a bug that lives in the brain and synthesizes a drug like PCP.

That and the transmission system needs work- after the ant is dead you have a spore stalk emerging from the victims head, something that is rather easy to spot and destroy. Preferably with fire.

[Stuart]

I don't think the method the fungus uses can be applied to human beings. Plus we already can have diseases that screw with the human mind- just engineer a bug that lives in the brain and synthesizes a drug like PCP.

There are already engineered agents that act like iinfluenza but release snake or jellyfish toxin. Whether they've been weaponized, I do not know.

That and the transmission system needs work- after the ant is dead you have a spore stalk emerging from the victims head, something that is rather easy to spot and destroy. Preferably with fire.

I was thinking more of the bit where it controls the mind then kills the host by eating its brains. A big part of the effectiveness of bioweapons is the fear and terror they cause. This one seems ideally suited to creating alarm and despondancy across the bulk of the population.

[Simon_Jester]

In theory yes, but by the time you got done making it effective enough to be a useful terror weapon, it would be a completely different organism.

The compulsions it applies to the ant seem to be rather basic ("CLIMB! GRAB LEAF!"), and it kills the ant shortly after taking over their brain. It depends on the ant's moldering corpse being left out for sustained periods of time in order to spread, too.

A precisely analogous fungus in humans would probably just trigger several hours of delirious compulsion to perform certain tasks (probably very elementary ones), followed by death... and unless you're already in an environment where corpses aren't being disposed of appropriately, that's going to be the end of it. By the time the fungus sprouts and starts sending out spores, any reasonably modern society would already have picked up the body, autopsied, found evidence of the mold, and burned the body.

[Junghalli]

Would it be unreasonable to launch an effort to exterminate that fungus to prevent anyone from ever figuring out how to use the stuff against people?

Yes, I'd say trying to exterminate every infectious agent in the world that could potentially be modified into something dangerous to humans with much more advanced biotech than we have now would be pretty unreasonable. Especially as if we tried to do it without really advanced biotech to make highly species-specific targetted killing agents I doubt we'd have much of a biosphere left after all the collateral damage.

[Broomstick]

My favorite "one creature takes over another" critter - and it's not a fungus, it's a barnacle. Fortunately, I am not a crab:

Sacculina

[Drooling Iguana]

I've known about this stuff for years, it's very interesting. Though it seems to me that weaponizing it would be exceedingly difficult, as a human brain is just a tad more complex than an ant brain.

Forget about using it to control humans, just modify it so that instead of compelling ants to cling to leaves it instead compels them to attack and feast upon your enemies. Do you have any idea how many ants there are out there? If they could be organized into a single army they'd be unstoppable.

[Samuel]

I've known about this stuff for years, it's very interesting. Though it seems to me that weaponizing it would be exceedingly difficult, as a human brain is just a tad more complex than an ant brain.

Forget about using it to control humans, just modify it so that instead of compelling ants to cling to leaves it instead compels them to attack and feast upon your enemies. Do you have any idea how many ants there are out there? If they could be organized into a single army they'd be unstoppable.

You do realize you sound like a mad scientist, right?

The problem is for the fungi to spread it has to kill the ant which makes it a rather poor weapon to inspire your ant legions.

[Ilya Muromets]

Really, organisms that turn other organisms into little puppet zombies aren't that unusual in nature. A Discover magazine had an issue devoted to them years ago. In fact, I think there's even a web summary of said issue. Hold on, I'll find it...

Ah, here we go.

[Shroom Man 777]

Snails also have them, the organism prompts the snails to climb up grass and get themselves eaten by cows, since the organism (don't know if it was a fungus or a fluke) reproduces in the cow's digestive tract and proliferates through cow shit.

[Junghalli]

It seems to me like this all this wacky and wild stuff that happens at the level of insects and small animals that you don't get to see much in the kind of animals we're more familiar with. I guess being small (and therefore numerous) and fast reproducing gives evolution more potential variation to work with.

[Dooey Jo]

Having a small and highly specialized nervous system also doesn't hurt...

Seriously, you have to be pretty paranoid if you think these things may soon be able to jump over to and have similar effects on even vertebrates, let alone mammals or humans.

[Lagmonster]

Okay, well, in SOME cases toxoplasmosis does affect human behaviour. It's suspected to be marginally effective at making women more sexually open, men more jealous and aggressive, and has been said to make a person more likely to have a car accident.

The rates are small and the data incomplete, but even if it changes your brain enough to make you risk running a yellow and getting killed, to the individual that's a pretty fucking big deal.

[hongi]

Do you have any idea how many ants there are out there?

I think the numbers run into the quadrillions.

[Dooey Jo]

Yeah, but that's not going to be so easy unless what you want are very general things, or have a means to also implant knowledge into a brain. Maybe you can have a drug that makes all affected thirsty, but not one that makes everyone thirsty for Diet Coke™, because for that you'd need to tap into memories and things that are going to be different in different individuals. It works well on insects because their brains (or more accurately, their rather decentralized nervous systems) are already made to do a few specific things.

Okay, well, in SOME cases toxoplasmosis does affect human behaviour. It's suspected to be marginally effective at making women more sexually open, men more jealous and aggressive, and has been said to make a person more likely to have a car accident.

The rates are small and the data incomplete, but even if it changes your brain enough to make you risk running a yellow and getting killed, to the individual that's a pretty fucking big deal.

Well, even if those correlations turn out to be valid and causative, causing encephalitis and possibly have a statistical effect on dopamine levels is a pretty far cry from the very specific behaviours these parasites induce.

[Surlethe]

Split a couple of zero-content posts to the Barrel.

[Shroom Man 777]

I wonder, in terms of neurology or something, if it's easier for the parasites to make these invertebrate animals do certain crappy behaviors because of the fact that they're not sapient at all and are just ruled by simple programming, whereas complex creatures with complex brains are able to "think" and "reason" (not REAL reason, but still, something like that) more than invertebrates whose brains are just simple biological computers anyway. Man, how complex would it be to make a parasitic organism induce certain specific behaviors on people (aside from just increasing their tendencies towards a particular set of non-specific attributes due to neurologic effects)?

[Ilya Muromets]

I wonder, in terms of neurology or something, if it's easier for the parasites to make these invertebrate animals do certain crappy behaviors because of the fact that they're not sapient at all and are just ruled by simple programming, whereas complex creatures with complex brains are able to "think" and "reason" (not REAL reason, but still, something like that) more than invertebrates whose brains are just simple biological computers anyway. Man, how complex would it be to make a parasitic organism induce certain specific behaviors on people (aside from just increasing their tendencies towards a particular set of non-specific attributes due to neurologic effects)?

A lot of such "zombifying" parasites do seem to just jack the nervous system of their host in some way. And, well, like you said, those host nervous systems are mostly rather simple. I'm betting that it's got something to do with funky neuro-chemical manipulation more than anything. Even the sacculina, which actually changes the body layout of its host rather than just making it behave in a certain way (it makes male crabs physically female), does so through the manipulation of hormones.

To actively do the same to something as complex as a human? Assuming that it's mostly attributed to neuro-chemical manipulation, a human body's one helluva complex brew of neurotransmitters and hormones and whatnot to actively manipulate into some kind of coherent behavior. It just seems too overly complex for an organism to evolve in such a way for very little real biological gain. As for actively making one? Considering how relatively simple most genetic engineering is today, there's little chance of making anything like one of Khan's brain parasites from Star Trek any time soon, if ever.