The media is carrying stories of a study in Science showing that Camponotus workers specialize into three behavioral classes, and that workers tend to move through these roles as they age. This result is interesting, but not terribly surprising as a similar pattern is known in the better-studied honey bees.
The reason the paper appears in Science, rather than a more specialized journal, is methodological. Danielle Mersch, Laurent Keller, and Alessandro Crespi have automated the observation of an ant colony. Basically, they built the perfect Orwellian ant-watching machine.
Each ant is labelled to be recognized by high-resolution video, and her position and social interactions are recorded continuously for the length of the experiment. The technique produces a staggering amount of data from relatively little effort once the initial tedious bits of gluing barcodes on ants are out of the way.
Check out just one short clip:
After extending this recording to six colonies for 41 days, Big Brother crunched the numbers:
Network analyses of over 9 million interactions revealed three distinct groups that differ in behavioral repertoires. Each group represents a functional behavioral unit with workers moving from one group to the next as they age. The rate of interactions was much higher within than between groups. The precise information on spatial and temporal distribution of all individuals permitted calculation of the expected rates of within- and between-group interactions. These values suggest that the network of interaction within colonies is primarily mediated by age-induced changes in the spatial location of workers.
The really interesting bits will come later, in my opinion, when the method is harnessed across other species. Assuming the ants don’t first figure out what we’re up to, that is.
source: Mersch, Crespi, Keller (2013) Tracking Individuals Shows Spatial Fidelity Is a Key Regulator of Ant Social Organization. Science, Published online 18 April 2013 [DOI:10.1126/science.1234316]
See also Ed Yong’s “Tracking whole colonies shows ants make career moves” commentary in Nature.