(Hymenoptera: Formicidae)

Weaver ants are one of the most remarkable examples of social cooperation in nature. However, there are few studies to date on the particular aspects of their social behavior. In this study, we describe the behavioral repertory of Camponotus (Myrmobrachys) senex, a Neotro-pical weaver ant. A colony collected in the field was transferred to the laboratory for elaboration of an ethogram. Part of the colony: 20 wingless queens, 176 workers, 7 pupae, 30 larvae and 667 eggs, was conditioned in test tubes and put into two plastic boxes. One box was designated as nesting area and the other as foraging area. Both boxes were connected to each other. The ethogram was based on 20 hours of qualitative observations, followed by 50 hours of quantitative behav-ioral observations, “all occurrence sample ” method (sensu Altmann 1974). We identified 58 different behaviors (30,651 registers), distrib-uted in 10 behavioral categories. The most frequent categories were: immobility (0.4031%), grooming (0.1393%), exploration (0.1306%) and brood care (0.1035%). Immobility was the most frequent category in all castes and we suggest that immobility might be an energy saving strategy in C. senex. Workers displayed a more diversified behavioral repertoire with 57 different acts whereas, queens displayed 34 different acts. The use of male larvae by weaving nests can suggest an additional function for males, in addition to their usual sexual role. It is hoped that new taxonomic and behavioral studies will be carried out in order to obtain a better understanding of labor division in C. senex. Our results provide baseline data for future comparisons about evolutionary patterns in nest building behavior in ants as well as to the study of the genus Camponotus as a whole