July 30, 2015, 8:17 a.m.
The insects are able to transport objects such as food that are much larger than themselves by intuitively understanding when to be part of the collective muscle and when to play an individual “scouting” role for the group, researchers found.
Experiments using the Cheerios breakfast cereal showed how groups of a dozen or more ants working in unison could haul much bigger items by pushing in the same direction. But crucially, when the group moves off-course or trouble looms, the ant who first realises the problem transforms into a highly individualistic leader.
The experiments involved ants moving pieces of Cheerios breakfast cereal (Michael Himbeault/Flickr)
This ant signals the need for a direction change by tugging at a different angle – and her colleagues instantly accept the decision and follow suit.
“The individual ant has the idea of how to pass an obstacle but lacks the muscle power to move the load. The group is there to amplify the leader’s strength so that she can actually implement her idea,” said Ofer Feinermann, the study’s lead author.
But the lead ant will only carry the baton for a short period, typically yielding to another 10 to 20 seconds later, by which point another ant has become best placed to make leadership decisions.
“As far as we can tell the scout is no different to the other ants. No one designates the leader, she designates herself because she has current knowledge about the correct direction,” he added.
Ants are among the very few species, besides humans, that organise among themselves to collectively carry loads far heavier than an individual member of their species.
The study by the Weizmann Institute of Science in Israel was published in the journal Nature Communications.