
Ants Build Complex Structures With a Few Simple Rules - digital55
https://www.simonsfoundation.org/quanta/20140409-the-remarkable-self-organization-of-ants/
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bayesianhorse
Ants also have a risk-management algorithm and can be compared to businesses.
Their business model is to send ants out of the nest and bring back calories,
water and protein. These resources are then turned into more ants.

In the most ideal case, this is an exponential growth curve. But "investing"
in a new food source, meaning to send out a fraction of the capital to get
more revenue, is also risky. There are predators, rain and heat. Would be
tough luck on a colony, if they send out half the ants at the same time and
then some hungry predator just feeds off the ant street.

So the ants do have some sort of risk management algorithm. I don't know how
it works completely, but essentially the decision to send out workers is
influenced by the amount of workers in the nest and the frequency of ants
coming back with a "profit".

As with any well managed portfolio and a little bit of luck, the growth curve
then is exponential, while not exactly crazy, and the end result after a few
years is a prosperous colony, having accumulated so much capital, that they
don't know how to spend it on growing themselves.

That's when they start to spawn a new generation of ant queens, which is a
horrendously wasteful and expensive exercise, but all of these newly mated ant
queens, if she survives the first few days, will go into stealth-mode and
found her own startup colony.

~~~
Someone
I think there also is a limit to growth. If population density gets to high,
the average ant has to walk so far for food that getting food costs more
energy than the food brings in.

~~~
bayesianhorse
There seems to be a an intellectual reflex that whenever the topic of
exponential growth comes up, people have to bring up growth limits and
population density...

In this case though, I don't think that resource limits apply that much.
Individual ants feed each other, so they can survive quite long periods
without food, and they don't grow much beyond carrying capacity. If
circumstances change, they can do a "soft landing" by downsizing the colony
slowly or even moving the colony.

In fact, colony size seems to be most often limited by burning off excess
capital in sexual broods.

Compared with most other insects, ants are actually much worse at building up
biomass. But the queen ant's survival is actually safer because the colony
manages risk and growth.

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danso
I feel compelled to repost the NYT's excellent, terrifying article on "Crazy
Ants", particularly the section about how the constant stream of dead ant
bodies also creates functional structures:

[http://www.nytimes.com/2013/12/08/magazine/crazy-
ants.html](http://www.nytimes.com/2013/12/08/magazine/crazy-ants.html)

> _Soon he and his wife were waking up to find vast, frantic networks of ants
> zipping around the kitchen floor in all directions. When the picture on
> their 50-inch box television started flickering, Mike took off the back
> panel and found the guts throbbing with ants. He got rid of the television._

 _Outside, dead ants began pooling around the base of the house in heaps so
high that they looked like discarded coffee grounds. (It’s common in Texas
these days for a person who is shown one of these heaps of dead ants to take
several seconds to realize that the solid surface he or she is scanning for
ants actually is the ants.) Mike laid out poison, generating more heaps of
dead ants. But new ants merely used those dead ants as a bridge over the
poison and kept streaming inside._

~~~
methodover
Wow, what an article.

Ants in Texas are terrible. Off the top of my head --

1\. I was stung by a swarm of fire ants when I was ten years old. I had been
standing, and hadn't realized that I was standing right on an ant bed. I
remember an adult carrying me away, and blinding pain.

2\. Ants infested the office of my last job in Texas. Every desk was equipped
with an ant motel. One of the water fountains near my desk was completely
unusable because of the infestation. All attempts to eradicate the ants
failed.

3\. At my last apartment in Texas, the ant infestation was so bad that
significant numbers of them would crawl up the tires and get in my car. I'd be
driving along and realize that there were ants crawling on my hands. I was
actually worried that I would take the infestation with me when I moved to the
bay area -- but thankfully I haven't seen one since I moved.

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will_brown
There is another interesting structural phenomenon built by ants, mass graves.

I have first hand observed that when a ant pile/mound is damaged (pour water
on the mound, spray with ant poison, or just kick the mound), the ants over
the next few days will simultaneously rebuild the original structure and
relocate the dead ants to a newly build structure. Though I can not recall if
the new structure is composed entirely of the dead ants or if dirt is involved
as well.

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niels
Here's a good explanation of Ant Pheromones and how it's used as a routing
topology in the MUTE P2P software.

[http://mute-net.sourceforge.net/howAnts.shtml](http://mute-
net.sourceforge.net/howAnts.shtml)

~~~
cgh
Related: "Ant Colony Optimization" by Dorigo and Stutzle. They also provide
sample code in C.

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overdrivetg
Anyone interested in this kind of emergent behavior should check out a great
project I worked on years back called Starlogo at the MIT Media Lab. It was
designed to help anyone understand decentralized systems and emergent
behavior.

Here's a video with a demo of ants foraging for food - basically ants are red,
food is blue, and pheromones are green:
[https://www.youtube.com/watch?v=9liT8epLnAQ](https://www.youtube.com/watch?v=9liT8epLnAQ)

You could "program" individual ant behavior and tweak parameters to see how
that impacted the overall behavior (how far do ants go from the nest? How fast
do pheromones dissipate? etc).

It's mostly defunct now, but it looks like there is an online version called
StarLogo Nova, you see a sample and play with it at
[http://www.slnova.org/djwendel/projects/2/](http://www.slnova.org/djwendel/projects/2/)

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theorique
Ants are really good at working as a team.

The famous short story "Leiningen versus the Ants" describes the scary power
of a massive ant infestation.

[http://www.classicshorts.com/stories/lvta.html](http://www.classicshorts.com/stories/lvta.html)

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aaronetz
I've just recently watched a very good documentary about ants:
[https://www.youtube.com/watch?v=Z-gIx7LXcQM](https://www.youtube.com/watch?v=Z-gIx7LXcQM)
. They are a truly amazing organism. Does anyone know of any ant games? I
thought it would be cool to have a strategy game where you build an ant
colony, defend it from disasters and attackers, etc.

~~~
pyronite
SimAnt has a good reputation:
[http://en.wikipedia.org/wiki/SimAnt](http://en.wikipedia.org/wiki/SimAnt)

Old, but still a novel concept.

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ntoll
I'm currently reading "Ant Encounters - Interaction Networks and Colony
Behavior" by Deborah M.Gordon. It covers a lot of related material and is a
very engaging read.

~~~
inoop
I highly recommend 'Self Organization in Biological Systems' by Camazine et.
al.

Each chapter describes a single mechanism found in biology: e.g., ant
foraging, termite nest building, etc. For each such mechanism they first
provide an accessible, well-written description of the process from a
biological perspective, and then go on to simulate it using numerical analysis
and computer simulation.

[http://www.amazon.com/Self-Organization-Biological-
Systems-P...](http://www.amazon.com/Self-Organization-Biological-Systems-
Princeton-Complexity/dp/0691116245)

~~~
ntoll
Thanks for the recommendation. It's in my to-read list ~ along with far too
many other books ;-)

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dfc
If you are ever interested in browsing (reading from start to finish would be
a lot of ants reading) a fascinating book about ants take a look at Ants by
Holldobler and Wilson:

[http://www.amazon.com/The-Ants-Bert-
Holldobler/dp/0674040759](http://www.amazon.com/The-Ants-Bert-
Holldobler/dp/0674040759)

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taivo
There's quite a nice and easy to use program (a programming / modeling
environment) for exploring and getting an intuition of how a system of many
individuals who follow simple rules and interact with each other can give rise
to interesting complex behavior. The modeling environment is called NetLogo,
and it's basically a multi-turtle version of the old famous Logo programming
language. It has lots of different models included in its example model
library, including about ants, and the models have modifiable source code. I
have quite enjoyed playing around with it, and have even used it in some
presentations about how simple rules can give rise to complex behavior.

[http://ccl.northwestern.edu/netlogo/](http://ccl.northwestern.edu/netlogo/)

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th3iedkid
wow! its incredible how they design a lattice that can help all occupants
survive within water !

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lgieron
The ants bridge looks very much like structures from World of Goo, I wonder if
it has been an inspiration for the game mechanics.

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briantakita
Similar idioms can be used for building products with complex requirements
(with minimal incidental complexity) & resilient codebases.

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mildtrepidation
_Want your employees to cooperate better? Follow this ONE CRAZY RULE we
learned from ants!_

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bitwize
This is no job for traditional science; we'll need a whole new kind! Quickly,
to the Wolfram-Signal!

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webwielder
Nature's own artificial intelligence.

~~~
Glide
Wouldn't that just be intelligence?

~~~
mantrax4
Just like people believed the Universe revolves around Earth, they still have
this naive believe that they're the center of intelligence in the Universe.
Any other display of intelligence is explained as a combination of simple
chemical, mechanical and electrical processes. But don't be quick to judge
humans, though, after all, their brains are built on a combination of simple
chemical, mechanical and electrical processes themselves.

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hharrison
Yes. AI/cog sci could learn a lot from this. Intelligent structures are self-
organized, the order isn't imposed from above or from some "central
executive."

~~~
jerf
The correct tense is " _is_ learning". They've been studying this for years.
This is not news to the AI/cog sci community, to the point that it's insulting
to claim that it is.

~~~
hharrison
Yes and no. I am aware of the status of the field (well, AI less so). I myself
am a psychologist working on the self-organization of behavior. Yes, we have
been using examples like termites and ants for years. But we are far from the
mainstream. For example, in Pinker's _How the Mind Works_ , he dismisses self-
organization as "fairy dust".

Some aspects of our work have been trickling into the mainstream. But if you
don't assume that the mechanisms of mind are computations on representations,
then it is very difficult to get a job without compromising your principles.

And perhaps you could argue that the mainstream thinks this system of
computations is the result of self-organization on some lower level. And I
wouldn't disagree. But for the majority of the field that is just lip service.
Their research goals are to uncover the algorithms that the mind is running.
There's no self-organization at that level.

Of course there are always exceptions. But if anyone is still reading this and
is interested I can provide literature staking out the relevant positions.

------
prot
Now I always wonder: if such simple creatures as ants can build such complex
structures and are unbelievably successful as species, without any central
body enforcing their behavior, why do we humans, need all those numerous laws
and regulations that no human alone can fully comprehend? And why everyone
believes we need central authority in order to achieve something? Ridiculous.

~~~
snowwrestler
Their behavior is enforced directly by evolutionary constraints. If an ant
colony's behavior fails to be adaptive, that colony dies out.

Humans have developed intelligence and culture, which allows us to consciously
adapt our behavior over timespans shorter than a generation. Thus we also have
developed more adaptable rules that are embedded in culture rather than genes.

That said, both ants and humans arise from the same evolutionary process.
Human government is different from, but not any less natural than, ant
behaviors.

~~~
dllthomas
_" Human government is different from, but not any less natural than, ant
behaviors."_

Though genetic influence is likely more attenuated.

