Differences in foraging rate between loaded and unloaded foragers.

Differences in foraging rate between loaded and unloaded foragers of Atta and Acromyrmex species in Gamboa, Panama, with summary statistics on the number of trails observed per species (number of colonies in brackets), the total number of minutes of observation per species, the total number of ants counted while returning to their nests, and the foraging rates for loaded and unloaded returning workers: means (± SE) per genus and per species (see Table S1 for details).