April 22, 2009

Study shows how ants choose the best home

British scientists fitted rock ants with tiny radio-frequency ID tags to determine the process by which ants select a new home.

University of Bristol researcher Elva Robinson and colleagues gave the ants the choice of a nearby poor nest or a good nest located farther away.

The researchers found the colonies selected the superior site although it was nine times farther away than the alternative. And, the scientists said, the best nest was chosen despite the fact that very few individual ants made direct comparisons between the sites.

Approximately half the ants that first visited the near nest later switched to the far nest, but only a tiny minority that first visited the far nest switched to the near nest, the researchers said. That ultimately resulted in the entire colony ending up in the better nest.

Ants finding the poor nest were likely to switch and find the good nest, whereas ants finding the good nest were more likely to stay committed to that nest, said Robinson. When ants switched quickly between the two nests, colonies ended up in the good nest. Individual ants did not need to comparatively evaluate both nests in order for the entire colony to make the correct decision.

The research appears in the Proceedings of the Royal Society B.