Leaf Cutting Ant Forum

So, my stock room for Atta has, at times, around 100-200 colonies of Leaf Cutters. On occasion a twig or a leaf will fall in such a way that a bridge is formed either so a colony can forage around the room or, more often, they can reach their neighbour. I have seen many different behaviours over the years. Here's one or two observations for you to have a think about.....
1. If a large colony reaches a small colony of the same species the large colony, predictably, will raid the smaller colony and remove the antennae and often legs from the queen. The workers from the smaller colony will not try to defend the queen or the brood / fungus. The ;arger colony will then strip am of the assets from the smaller colony, fungus, brood and workers and carry it all back to the larger colony. The workers from the small colony will become active in the larger colony. The queen will die or be killed as part of this process.
2. If a colony of Atta reaches another colony of Atta and they are approx the same size, there is a very different type of behaviour exhibited. The colonies will scout each other out and there will be a standoff. Neither colony will raid the other and there will be little, if any, fighting. Rather the two colonies will begin cooperating with eachother. I have seen several colonies where this has happened. I have one at the moment where the two colonies have merged in to one. The two queens are seen beside each other and then, on other days, they are back on their own gardens.

I would be interested in your thoughts on this behaviour!
I will post more examples later.

I have actually put 2 unrelated Acromyrmex colonies together without any vetting of workers and they combined successfully. The rationale for this behaviour is, I think, that when they combine they actually increase the chances of survival considerably. Two queens can fight better than one. And they will reach independent size much quicker. I have, however, read a paper that suggests that after around 3 months of this cohabiting, the workers will suddenly turn on one of the queens and kill her. Question

In nature, after a nuptual flight, the queens tend to land and found colonies in close proxinity. I once collected 35 small colonies within a 3m radius. It is therefore not unheard of for two colonies to expand underground so that their scents and activites mingle. IN these circumstances I can imagine that there would be a degree of cooperation.