Abstract: Tatiana A. Novgorodova Dr. Tatiana A. Novgorodova, Institute of Animal Systematics and Ecology, Siberian Branch, Russian Academy of Sciences, Frunze ul., 11, Novosibirsk, 630091, Russia. E-mail: tanovg@yandex.ru Myrmecol. News 10: 115 Data are reported on a comparative analysis of the behaviour and work organization of different ant species tending aphids in multi-species communities. The "teams" of ants tending separate aphid colonies (milkers) are shown to include both "passive" and "active" foragers. The functions of the former are usually restricted to collecting and transporting honeydew. Active foragers are multifunctional. They can guard trophobionts, search for new aphid colonies and even coordinate the group activity to some extent in addition to the common functions (collecting and transporting honeydew). The comparative analysis of the schemes of interaction of different ant species with aphids has revealed that the depth of functional differentiation in working groups of milkers is caused by the requirements of an ant…