[xi]

AFAIK, it's completely decentralized. When a scout ant finds food, it returns back to the nest leaving a strong trail of pheromone. Ants tend to follow a pheromone trail and reinforce it on their return if they find food, so when a good source of food is found, a strong pathway is quickly established by a growing number of ants following the same route.

An ant may randomly leave a pheromone trail, which ensures that other, perhaps more attractive food sources are not missed. In general, the stronger the signal, the faster ants move with the less probability of diverging from the path.

This strategy ensures optimal area exploitation under varying conditions. For instance, if the food is concentrated in one or a few locations, you'll see a single column between the nest and the source, but when the food is scattered through the area, the ants would disperse too.

Source: an excellent book "Cells, Embryos and Evolution" where it was used as an example of how complex and seemingly organized and directed behavior could be achieved by a population of identical individuals acting under uniform rules.

[gizmo686]

Interesting, but as I understand the article, ants also use a TCP like protocol to make sure that make sure they don't send to many ants to a given food source. It sounds like the system you are describing would strengthen the trail until the food ran dry, regardless of if there are already more ants at the food than can take a piece at a given time.

Also, I remember learning about the pheromone trail years ago as established fact, so I'm pretty sure they are talking about a different system. It would be interesting to look at how the two interact (along with the other systems they use we have yet to discover).

[xi]

You are right, now that I read the original article, it appears the particular ant genus they were studying does not use pheromone trails. Since this ant species gather seeds which are scattered by wind and could be brought back by a single ant, they don't need to build paths to the food source. Instead a returning ant interacts with other ants which are ready to leave and the rate at which ants leave the nest grows with the rate at which ants return back (so a leaving ant is a data packet, a returning ant is an ACK packet).

The paper: http://www.ploscompbiol.org/article/info%3Adoi%2F10.1371%2Fj...