Nest separation and the dynamics of the Gestalt odour in the polydomous ant Cataglyphis iberica (Hymenoptera, Formicidae).

摘要

In the polydomous ant species Cataglyphis iberica [C. ibericus], nests belonging to the same colony are completely separated during hibernation. In order to examine whether this separation induces changes both in the hydrocarbon profile and in recognition ability between adult nestmates, groups of workers were separated for several months under two different conditions: at hibernation temperature and at room temperature. At room temperature, recognition remained unchanged but separation led to longer mutual antennations relative to non-separated controls. When half of a colony was placed under hibernation conditions, antennal interactions also increased in duration and a few aggressive interactions emerged between separated ants. This aggressiveness never reached the intercolonial level observed in this species. In both cases, the hydrocarbon profiles showed differences between individuals after separation while remaining homogeneous within each nest. This chemical modification may induce the longer antennations observed. After separated groups were reunited, individuals recovered their previous antennation pattern and a convergence in hydrocarbon profiles was again observed. These concurrent observations suggest that hydrocarbons are transferred between nestmates. In C. iberica, the formation of the colonial odour seems to follow the "Gestalt" model which allows all satellite nests of a colony to have a common colonial odour. In the field, temporary nest isolation during hibernation may inducedivergence between satellites. The role of adult transport in connecting nests during the active season to obtain an efficient Gestalt odour is discussed.