Mechanism for Real "Zombies" in the Animal World

[enorbet]

Greetings
I don't know if this is the right place to post this because I'm not certain how it is classified or if it can come under many headings. So please move this if it is better suited elsewhere.

I watched a video on pbs.org a few years ago and since I am just now writing here about it, you would be correct in concluding it had a powerful impact on me, creating many questions. The video was confined mostly to the insect world but it is my understanding similar events occur in slightly higher animals. What I am referring to is the complete, or what appears to be complete, reprogramming of a living thing to cease working in it's own behalf or for that of it's offspring when it has been injected by some neurologically active compound usually accompanied by the eggs of the injecting invader.

Often the change in behavior is very profound and extremely specific such as building a nest that could not possibly be utilized by it's own offspring but is exactly what the invader's offspring requires. The change is far more specific and profound than pictures or videos I have seen for example of spiders and the webs they weave when exposed to various drugs.

My question is how is it possible, by what mechanism have compounds evolved that are so specific as to cause such complex and detrimental behavior in the host?

I apologize for not being able to link the original video. I can no longer find it. I'm hoping someone else here finds this as fascinating as I do and can point to some printed material or other videos of this nature as well as give some insight into this amazing process.

 

[Ryan_m_b]

You may have seen a video on ophiocordyceps unilateralis, a fungus that causes ants to climb to the highest point they can in order to increase the chance of being eaten by grazing animals.

You can find a lot of information by looking through the wiki and googling the term. It's worth noting though that despite the pop culture label this is not at all similar to the notion of zombies.

 

[enorbet]

Hello and thank you for responding. Of course I didn't mean "zombie" in the pop culture meaning, especially since that requires a "state of undead" whatever that is supposed to mean. However I also didn't mean what seems to be incidental or merely induced insanity. What I am referring to has to do with, for example, wasps that inject spiders with some substance and their eggs. The spider then begins to create nests for wasp larvae... the ones that will soon eat their way out of the spider.

As I mentioned the induced behavior in each case is complex and directly benefits the invader. I will do some more searching to try to come up with at least one precise example.

Update: This is a bit closer and does include the fungus you mentioned but also has the wasp-spider pair I mentioned and also a caterpillar that once injected will protect wasp larvae but it still lacks some fascinating examples I saw before but I will keep looking.

http://io9.com/12-real-parasites-that-control-the-lives-of-their-hosts-461313366

 

[Bandersnatch]

For an example in mammals google toxoplasma gondii. It targets rats, making them e.g.like the smell of cats' urine. Cats being the final hosts. http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1690701/
There's some active research on its effects on humans too.

You should be able to find some discussion of the mechanism of action in the papers on the subject, but a quick primer on behavioural biology might be necessary to appreciate what's going on.
I recommend the following course:https://m.youtube.com/playlist?list=PLSb6fsJIpMXn3gjMWdH7SaN6rUdHuaWdh
The first dozen or so lectures especially.

 

[B0b-A]

... What I am referring to is the complete, or what appears to be complete, reprogramming of a living thing to cease working in it's own behalf or for that of it's offspring when it has been injected by some neurologically active compound usually accompanied by the eggs of the injecting invader.

e.g. http://en.wikipedia.org/wiki/Dinocampus_coccinellae

... by what mechanism have compounds evolved that are so specific as to cause such complex and detrimental behavior in the host?

Mechanism = http://en.wikipedia.org/wiki/Natural_selection .

Insects have been around for a lot longer than mammals, are more numerous, and have a shorter life-cycle, so have had more opportunity to evolve complex [parasitical] relationships.

 

[Borek]

Also worth remembering these mechanisms often coevolved (which means they could get quite complicated starting from a relatively simple form).

 

[enorbet]

Thank you all. Everyone has been quite helpful. I have some studying to do but I did find what I was looking for, a sort of "handle" on the physiological differences in insects and some lower animals that makes this possible, here
http://www.the-scientist.com/?articles.view/articleNo/31536/title/Animal-Mind-Control/

If you're not all that interested and just would like to know what I mean, this quote summarizes it.

In the caterpillar’s brain, a massive immune reaction is taking place—the invertebrate equivalent of a cytokine storm—and among the factors being released is an invertebrate neurohormone called octopamine.

The above and an interesting article on how in various experiments insects are now being controlled in three different ways by humans. One example controls the direction of a beetle's flight, another where a cockroach walks. Some of this study is in the interest of learning how to improve robots, especially "swarm-bots".

From an article on Wired.uk

We're a long way from directly controlling human minds remotely, but recent years have seen a string of breakthroughs in hacking the minds of insects. Insect brains are probably the simplest interesting brains, as insects can perform a range of tasks (flying, smelling, carrying, etc.) with brains that have numbers of neurons orders of magnitude less than those in complex vertebrates. A fruit fly has around 100,00 neurons, compared to 85 billion in humans.

So at the conjunction of neuroscience and robotics lie insects -- their tiny brains still too complex to model completely, but offering an easy way into modelling certain parts of the brain. It's how engineers from Sheffield and Sussex universities can claim they're preparing to upload the smell and sight parts of a bee's brain into a bee-like flying robot, enmeshed with human-created software to create a completely new "brain".

Somehow I had overlooked the effect of the vast differences in the the number of neurons and therefore possible results in insects and had little knowledge of what neurotransmitters were available to trigger them.