Why did the ants cross the road?

[lemur]

Recently I noticed a line of ants going back and forth across a stretch of bike-road. I decided to take a closer look and saw that the ants made basically no effort to avoid head-on collisions by forming a new lane. They just went in opposite directions bumping into each other and then going around each other. Does it really take so much intelligence to form a new lane to avoid spending your entire trip going against traffic?

[Mr Skeptic]

Yup, it takes about as much more to make the new lane as to make the first. These lanes are based on phermone trails, and making two lanes would mean that there would have to be two different phermones. Alternately, they could stick to one side of the lane, but that would vastly increase the risk of them getting lost. In any case, they do so like to be able to stop and greet each other whenever they see a new ant, just to make sure the ant is not from another hive.

[lemur]

Yup, it takes about as much more to make the new lane as to make the first. These lanes are based on phermone trails, and making two lanes would mean that there would have to be two different phermones. Alternately, they could stick to one side of the lane, but that would vastly increase the risk of them getting lost. In any case, they do so like to be able to stop and greet each other whenever they see a new ant, just to make sure the ant is not from another hive.

You really know a lot about ant hives. Could you also tell me about bee hills? Sorry, I couldn't resist that one. that makes sense that by branching out to make a new lane, they would just be widening the pheromone trail. I'm surprised that they don't at least have a tendency to follow each other's back-sides because that's where the pheromone comes out. If they did, you would think they would tend to form lanes/lines in different directions. I'm not so sure they like greeting each other, though. They may be hoping to run into an enemy to get a fight/meal (do they eat each other?). On the other hand, they may be totally indifferent either way.

[Mr Skeptic]

Well ants are fairly popular for study due to their extreme simplicity but resulting complex-looking behavior (called emergent systems). They're also popular for being a truly social species (unlike us). They can be truly social due to a genetic trick where their siblings are more genetically related to them than their children, so that they would be evolutionarily better off having siblings than children -- but that's a different topic. As for following a trail, it just takes a fairly simple automaton to do that (I've made one myself!). All it takes is turn toward the side where the smell is strongest. Not sure if there is more to it than that for the ants, otherwise they might get disoriented and go backwards. Hm, next time I see an ant trail I think I'll have to spin one around a bit, put it back on the trail, and see if it remembers which way to go.

 

But the laying down of the trail is where the real interesting part is. I've heard of suggestions for using the ant-pathing algorithm to make some of our paths.

http://en.wikipedia.org/wiki/Ant_colony_optimization

[TonyMcC]

If you looked from a great height at people going into and out of (say) a shop you might wonder why they don't organise themselves better by all going in one door and out of the other.

[Maximus Semprus Veridius]

Essentially they don't need to otherwise they would have evolved to make complex lane systems and round-abouts and other sorts of crazy and systematic ways to avoid catastrophical, species endangering bumps.

On a serious note though, I think it would probably take a massive amount of 'intelligence' to form just one more line going in the opposite direction, or it would take almost none singularly but the "group intelligence" would have to be greatly increased and many DIFFERENT pheremones would have to be evolved to make it effective. Just a theory.

[lemur]

They can be truly social due to a genetic trick where their siblings are more genetically related to them than their children, so that they would be evolutionarily better off having siblings than children -- but that's a different topic.

Why would genetic similarity correlate positively with sociality? Symbiotes are the ultimate social-cooperative systems precisely because they divide labor through combining radically different functions.

 

If you looked from a great height at people going into and out of (say) a shop you might wonder why they don't organise themselves better by all going in one door and out of the other.

 

Good point, though I think they probably do when the traffic volume gets heavy. I'm not sure if that's intelligence or just necessity because they have to walk behind someone going in the same direction to move forward.

[Moontanman]

Is an assumption being made here from the observation of one species of ant? I Have personally seen two species of ants move in lines of two lanes, each line going the opposite way. Some ants have more complex behaviors than others, some farm fungus or herd aphids, even store honey like fluids. Some keep slaves to the extent they are so specialized they cannot feed themselves with out the slave ants. Some ants sweep across the jungle floor never really stopping in one place, others live in trees that both house and feed them, in return the ants protect the trees from predators. Neither on can live with out the other, ants are cool....