By Akari Miki
The life of Megaponera analis ants is similar to that of a warrior – they search for a nest of termites, assemble an army, and attack. After about twenty minutes of intense fighting, the ants carry the dead termites to their nest and feed on them. During the fierce battles, some ants lose their legs or collapse under the weight of dead termites, and hence become slower than unscathed ones. Biologist Erik Frank at the University of Würzburg in Germany noticed that some ants were rescuing and carrying their injured companions. After this accidental observation, he performed experiments in which he painted the wounded ants and monitored them. He found that after being carried to safety, they recovered quickly as they learned to walk with fewer legs. According to Frank, the injured ants emit chemical signals that prompt rescue. This form of communication and rescue behavior evolved in these ants, because they maintain the population of the colony, ensuring that the army is large enough to successfully attack the termites.
In a commentary on this study, Peggy Mason, a neurobiologist at the University of Chicago, contrasted the rescue behavior of ants with that of mammals. Her research has focused on how rats rescue each other from traps. In an experiment, her group administered an anti-anxiety drug to rats and found that they were less inclined to release an entrapped rat. This discovery suggested that the rats exhibit empathy toward their companions in distress. In contrast, the ants do not exhibit such emotional response and simply respond to the chemical signals. Nevertheless, regardless of how the ants are motivated to help each other, natural selection has favored their rescue behavior.
Source: Greenfieldboyce, N. (2017, April 12). No Ant Left Behind: Warrior Ants Carry Injured Comrades Home. Shots: Health News from NPR. Retrieved April 16, 2017 from http://www.npr.org/sections/health-shots/2017/04/12/523313734/no-ant-left-behind-warrior-ants-carry-injured-comrades-home