Ants exhibit myriad complex social behaviors despite possessing only
teeny brains. Now new research suggests that teaching should be added to
the list of ant accomplishments.
Nigel Franks and Tom Richardson of the University of Bristol in
England studied so-called tandem running in Temnothorax albipennis
ants, during which two ants run a course between nest and food with
various stops and starts en route. The researchers found that the lead
ant who knows the way to the food slows down as the follower
familiarizes itself with the route and will not proceed until the
follower taps it on the back. The two also maintain a variable but
matching speed and distance over time.
"This behavior is beautifully
simple," Richardson says. "If one experimentally removes the
follower and taps the leader with a hair at a rate of two times per
second or more, the leader will continue."
Biologists have a definition of a teacher in the world of animals:
any individual who sacrifices some potential gain in order to educate a
naïve counterpart. In a report published today in Nature Franks
and Richardson argue that true teaching also requires feedback between
teacher and student. The ant duos qualify on both counts. "The
teacher provides information or guidance to the pupil at a rate suited
to the pupil's abilities and the pupil signals to the teacher when parts
of the 'lesson' have been assimilated and that the lesson may
continue," Franks notes. "True teaching always involves
feedback in both directions."
In the case of the ants, the teachers
sacrificed their own speed, as evidenced by the observation that they
reached the food source four times more quickly on their own than when
they had a student in tow. But the students found food more than a
minute faster with the help of their lesson and then often themselves
became teachers for other ants. Sometimes, however, knowledge of a food
source needs to be communicated faster than one-on-one training can
accomplish. In those situations, large ant groups often broadcast such
information through pheromone trails or other means. But tandem running
proves that teaching may develop even in organisms that lack large
brains, providing help for pupils with the tiniest of intellects. --David
Biello