It is an association in which one species benefits from the activities of another species. Lineu described this association with some grace, stating: Aphis formicarum vacca (the aphid of the genus Aphis is the "cow" of ants).
On the one hand, slaving has hostile characteristics, as aphids are held captive within the anthill.
Nevertheless, a harmonious relationship can be considered, as aphids also benefit from the ease of finding food and even the good treatment given to them by ants (transportation, protection, etc.). This association is considered harmonic and a special case of protocooperation by many authors, since union is not obligatory to survival.