Social organization in Leptothorax ants: within- and between-species patterns

Recent application of quantitative techniques to behavior (cf. Colgan 1978) has resulted in new approaches to undertanding social interactions among animals. A technique particularly widely-used for study of ant colonies is development of the colony ethogram, o r behavioral profile. We now have ethogram information for a wide variety of species. Most reports in the literature focus on a single colony (Table 1); variation within a species is rarely discussed. In addition, the colony time budget, an important second class of information, is generally not reported (Table 1). The appropriateness of behavioral comparisons across species is thereby severely limited by availability of only one type of behavior frequency catalog, for only one colony per species. Caste complexity and division of labor related to morphological or age variation comprise another type of information contributing to an understanding of social organization. As a rule, queens have smaller repertoires than do workers; majors have different ethograms than minors; and older workers display different behavior frequencies than do younger workers. Studies of morphology affecting behavior have concentrated on polymorphic species for which descrete worker castes can be distinquished; recent work has shown that, even for monomorphic species, worker size can bias behavior (Wilson 1978, Berbers and Cunningham 1983). A reasonably complete description of social organization for a n ant species should treat ethograms, time budgets, and behavioral caste specialization, both within and between different colonies. Here I report such details for three colonies of Leptothorax ambiguus. This information is then compared to data from the closelyrelated L. longispinosus to arrive at an understanding of betweenand withinspecies variation in social behavior.