RESPECTIVE CONTRIBUTIONS OF LEADER AND TRAIL DURING RECRUITMENT TO FOOD IN TETRAMORIUM-BICARINATUM (HYMENOPTERA, FORMICIDAE)

This paper describes the food recruitment strategy of the ant Tetramorium bicarinatum, at both the individual and collective levels. The general organisation of recruitment used by this species during the exploitation of sucrose solutions shows similarities with group recruitment described for other species. However, our experiments demonstrate that in T. bicarinatum, the first trail laid by a recruiter during its return trip to the nest is more efficient than in other species using group recruitment, for example Tetramorium impurum. Moreover, the efficiency of the first trail of a T. bicarinatum recruiter is comparable with that of Tapinoma erraticum, a species that uses mass recruitment. Despite the efficiency of the trail, choice experiments show that the recruited workers prefer to follow the leader rather than the first trail, suggesting the emission of a more attractive signal by the leader on its way back to the food. The function of the leader in this strategy is discussed in terms of collective decisions.