…they just change jobs.
A study by Schofield et al out this week in Behavioral Ecology and Sociobiology measures the efficiency of leafcutter ant mandibles as they wear with age, noting that individuals with the most worn jaws are less than half as effective at cutting. Instead, these older ants spend more time transporting the leaf fragments sliced by their sharper sisters:
I would also like to nominate this paper for a Most Informative Title award, a category I just created, for encapsulating their entire study in a single sentence: “Leaf-cutter ants with worn mandibles cut half as fast, spend twice the energy, and tend to carry instead of cut.” You almost don’t need to read the paper, except the figures are kind of pretty.
source: Schofield, R. M. S., Emmett, K. D., Niedbala, J. C., Nesson, M. H. 2010. Leaf-cutter ants with worn mandibles cut half as fast, spend twice the energy, and tend to carry instead of cut. Behavioral Ecology and Sociobiology, online early DOI: 10.1007/s00265-010-1098-6.