INDIVIDUAL FLEXIBILITY AND TEMPO IN THE ANT, PHEIDOLE DENTATA, THE INFLUENCE OF GROUP-SIZE

This study investigates individual flexibility of foraging ants (Pheid ole dentata) when the number of nestmates is altered by establishing b roodless and queenless colony fragments all originating from a single big colony. Scouts from small groups (5 to 15 ants) behave like solita ry foragers. They feed for long periods of time, they return slowly in to the nest, and they recruit weakly. The ingested food is distributed by trophallaxis. Scouts from larger (20- to 30-ant) fragments forage more socially. Feeding and return times are short and recruitment is s trong. Later the food is always transported into the nest. Two alterna tive mechanisms are discussed to explain the differences in individual foraging behavior. For the first-individual flexibility-assumptions h ave to be made about the capabilities of the individual, its work repe rtoire, and decision making outside the nest. The second mechanism tak es into account that ants ape capable of perceiving CO2 concentration differences and that ant groups are more active at higher CO2 concentr ations. The organizational differences at the group level are explaine d simply by tempo differences in individual ants without making assump tions about individual capabilities.