SOCIAL-ORGANIZATION IN THE GUEST-ANT FORMICOXENUS-PROVANCHERI

The results of an investigation on the division of labour in the guest -ant Fomicoxenus provancheri, conducted by observing colonies containi ng individually marked adults, are presented. Five colonies of Formico xenus were installed in the laboratory with their hosts, Myrmica incom pleta, in order to document, over 10 d, the location of individuals as well as individual and interactive types of behaviour. The results sh ow that each colony of Formicoxenus consists of three groups: a group of nurses who remain in the Formcoxenus nest (some 21% of the colony's members); a group of scouts who spend most of their time in the exter nal area (18%) and a very large group of individuals specialized in li cking ('shampooing') the host to obtain regurgitations (61%), who esse ntially remain in the Myrmica nest. Division of labour in Formicoxenus appears to be a special adaptation to the xenobiotic way of life. The apparent link between social structure and the probability of profiti ng from trophallactic exchanges with the host species could lead to in teresting predictions on the division of labour in other guest-ants.