The researchers found that around 40% of the workers were nurses, which almost always stayed with the queen and her brood. Another 30% were foragers, which gathered most of the colony’s food and were found near the entrance to the nest. The rest were cleaners, and these were more likely to visit the colony’s rubbish heaps.Even more interesting to me is the way the data was collected:
The workers move between jobs as they get older — nurses are generally younger than cleaners, which are younger than foragers. Honeybees go through similar transitions from young nurses to older foragers, but this study provides the clearest evidence yet that ants do the same.
Nevertheless, these career changes were not clear-cut. “You can find very old nurses and very young foragers,” says Mersch.
The team reared six colonies of carpenter ants (Camponotus fellah) in the lab and tagged each worker with paper containing a unique barcode-like symbol. The colonies — each comprising more than 100 ants — lived in flat enclosures filmed by overhead cameras. A computer automatically recognized the tags and recorded each individual’s position twice per second. Over 41 days, the researchers collected more than 2.4 billion readings and documented 9.4 million interactions between the workers.Got that? 2.4 billion readings in 41 days. As computers get ever faster and scientists learn to use them more cleverly, all sorts of interesting research possibilities open up.