Energetics of Trail Running, Load Carriage, and Emigration in the Column-Raiding Army Ant Eciton hamatum

For workers at 28°C, standard V̇o2 = 0.166 M.84 where V̇o2 is ml h−1 and M is mass in g. At the same temperature, pupal V̇o2 = 0.156 M.83. Gross cost of transport (GCOT) and net cost of transport (NCOT) decreased with body mass and running speed, log GCOT = 0.87 − (1.05 log s) − (0.55 log M) and log NCOT = 0.51 − (0.92 log S) − (0.66 log M) where GCOT and NCOT are ml O2 g−1 km−1, S is cm s−1, and M is mass in g: The energetics of load carriage was measured in workers carrying pupae. The mean V̇o2 Of laden ants (mean mass .0108 g) was 5.72 ml O2 g−1 h−1. The mean respiratory exchange ratio of inactive ants in a bivouac was 0.72, that of unladen workers while running was 0.68, and that of pupae was 0.64. A model is developed and presented as a computer program (BASIC) to predict the energy spent for maintaining a raiding column, for colony emigration, and for a colony while in bivouac. The energetic performance of Eciton hamatum is compared with that of a leaf-cutting ant, Atta colombica.