The Ants Go Marching

Herding is generally associated with cattle and sheep. The ones doing the herding are usually people or dogs. Ants are also herders! In a similar way that ranchers watch over and herd their livestock, ants herd aphids. However, I do not believe the methods used by ants would be considered ethical for humans to use on livestock.

The ant-aphid relationship has been taught as mutualistic. The aphids provide honeydew (sugary excrement) at no cost to themselves. The ants consume the honeydew and in exchange for this delightful treat, protect the aphids from predators.

The large leaves of this milkweed plant harbor many vicious predators.The ants watch over their precious colony to ensure the continued supply of honeydew.

How "mutual" is this relationship though? Researchers have found that ants sometimes clip the wings off the aphids to keep them from flying away. A recent study has found new mechanisms of control. Ants are known for their elaborate pheromone communication and control. In the study, researchers found the chemicals ants use to mark their territory are also used on the aphid colonies they are supposedly "watching over." The chemicals tranquilize the aphids and keep them near to their herders. In this way, the ants have a constant supply of honeydew and complete control of their colony. I suppose this control mechanism is similar to an electric fence keeping cattle from breaking free...

http://www.sciencedaily.com/releases/2007/10/071009212548.htm