Ants know they are deadly

In ant colonies, the survival of the group depends, in many cases, on some of its members taking risks . This role is usually reserved for the older individuals, who venture to explore remote areas of the colony while the young workers remain safe, taking care of "domestic" tasks within the nest. In this way, a greater average longevity of the ants and, therefore, of the colony is achieved.

But how do these social insects know when their time is near? Do you simply have an internal "life clock" or are you aware of your health? To find out, Dawid Moron and his colleagues at the Jagiellonian University in Poland have carried out a series of experiments with Myrmica scabrinodis . In each of the eleven colonies studied, half of the ants had their lifespan reduced by exposing them to carbon dioxide (which acidifies their blood and damages their nervous system) or by damaging their coat to expose them to infection. After five weeks, and to the surprise of the researchers, these ants began to leave the colony in search of food earlier and more frequently than their "healthy" sisters of the same age.

Details about this curious behavior have been published in Animal Behavior magazine.

New Scientist (www.newscientist.com)