Imagine that you are an ant living happily in your colony hidden between two rocks. One day a big dog runs over the rocks and dislodges one, breaking up your nest and leaving you and your fellow ants exposed and without a home.
What strategy do you follow to be able to survive when this happens?
You look around and, although it is risky, you know that you need to be one of the ants to go out and look for a new nest site.
You leave your damaged nest and bravely step out into the sunshine, you are looking for another crevice between rocks that will be an ideal site for a new nest. Other brave ants are also leaving the nest to search out a new site.
You find a new site and look around. Would this make a good nest? You check out whether it is the right size, how many openings it has, whether there are already any dead ants here and then run back to the nest.
When you get back you wait for some other ants to join you before you head back to the nest you have found to show them the potential site. The key to the strategy is that you wait longer if you have found a poor site and less time if you have found a good site.
The ants that follow you to the potential site also make a judgement of how good it is and return to the nest. They then wait for some other ants to join them, again waiting longer for a poor site and less time for a good one.
Once you have shown your site to others then you look around the damaged nest and find another ant who takes you to a different potential site. You then judge this site and head back to the nest once again.
Very quickly a lot of ants are making judgements about different sites. You meet up with another ant and go to look at another site. The ant that you are with now had only just arrived back in the old nest before he headed out again, you must be going to a good site.
When you arrive you find that the new site is packed with ants. You sense that there are enough ants here for this to be the place to make the new nest. Everyone else senses the same thing and you all go back to fetch the main brood of ants who are protecting your queen.
By working together the ants are able to quickly check out a lot of new sites and identify the best one for a new nest.
The strategy works because the ants wait less time to go back to a good site which means that ants are arriving there more often then they are arriving at a poor site. An ant coming from a good site will go back there almost immediately taking other ants with him. One coming from a poor site might wait a minute before going back, in that time a lot more ants will have returned to the good site. After a while a lot more ants end up at the good site, which is then selected.
Amazingly this co-operative behaviour is really how some ants work when then need to find a new nest site.
I wonder if it has any applications to crowd-sourcing solutions to problems?
Image courtesy of sweetcrisis / FreeDigitalPhotos.net