Age-related changes in aggression in ant cataglyphis cursor (hymenoptera, formicidae): influence on intercolonial relationships.

Cataglyphis cursor forms monogynous societies which may however accept some foreign viduals. The factors influencing the degree of aggressiveness of the workers have been studied as follows. We have shown that the aggressive behaviour is expressed mainly by the foragers, the nurses are very little. aggressive. We observe therefore an evolution in the reactivity of the workers to a foreign odour in terms of age-related changes. However the closing of the society still depends on the behaviour of the foragers. Among the socia insects young workers are generally adopted by foreign colonies even if these colonies are completely closed to any other adult ants. Experiments allowed us to specify that young workers are recognized- as foreigners by another colony after the 4th day of age. Afterwards the adopted young ants were put back at different ages into their original colony, where they were recognized and accepted ty their sisters. The discussion is based on the origin of the colony odour. If this odour is formed from cuticular substances, in C. cursor their origin is probably endogenous, and predominant in comparison with the odours ac4uired from the environment (including that of the adoptive colony). Such an individualistic recognition system is known in only one other social insect species, the sweat bee.