Why do ants commit suicide?
Army ants are like most ants, but lack permanent nesting sites. They constantly march en masse to look for foods. The ants however, are blind. To follow each other, they leave a pheromone trail that the other ants follow. When it works, ants can lead larger groups back to food. However, there is a chance that this method fails, and the ants will simply follow the ant in front of them, ending up in an endless loop of following until the ants die. This phenomenon is known as an ant mill.
This phenomenon was first noticed in 1936, when biologist T.C. Schneirla came across a mill of hundreds of ants. Heavy rain did not stop the ants, and eventually all of them circled until their death. He noted in a paper :”On the spot of yesterday’s phenomenon little or no circling is to be seen. The entire area is strewn with the bodies of dead and dying Ecitons. A few of the survivors wander about slowly, while no more than three dozen of them form a small … and rather irregular circular column in which they plod around slowly, counterclockwise.”
This phenomenon can be seen as a natural example of an information cascade. This is because the only information that the ants receive on where to go is based on following the ant in front of it. Ant mills can be considered an in correct cascade, and the normal following behavior to be a positive cascade. This shows how information cascades can be easily correct and incorrect, and how it is logical for decisions to be made based on the cascade, and not external stimuli.
http://www.mnn.com/earth-matters/animals/stories/why-do-army-ants-commit-suicide
interesting!