Long-term observations of individual excavators.

Shown are, for each of the 12 observed workers, the duration of its continuous excavation activity, the number of pellets excavated and the number of pellets carried within that time, the resulting digging and transport rates, the average time spent for excavating a single pellet (mean±SD), the locations where the pellets were deposited and, for those pellets deposited in the box, the Index of Dispersion (DI) for their distribution on the 16 square areas. A DI close to 0 is an indicator of a regular distribution. Values around 0.5 characterise random distributions, while values close to 1 and higher indicate an aggregated distribution. For four individuals (1, 2, 3 and 11) not every pellet dropping could be observed, and therefore no dispersion indices were assigned to them.