Abstract

NOBUA BEHRMANN, Beatriz E. et al. Colony size and composition in three Pogonomyrmex ant species (Hymenoptera: Formicidae) in the central Monte desert, Argentina. Rev. Soc. Entomol. Argent. [online]. 2010, vol.69, n.1-2, pp.117-122. ISSN 1851-7471.

Colony size in ants is associated with important ecological characteristics such as foraging strategy. Though colony size has been studied with some detail for several North American species of Pogonomyrmex harvester ants, it remains unknown for South American species. We studied colony size, composition, and nest structure of three species of Pogonomyrmex harvester ants inhabiting the central Monte desert in Argentina: P. mendozanus Cuezzo & Claver, P. inermis Forel and P. rastratus Mayr.  We excavated two nests of each species, and collected all individuals in each nest. All three species have small colonies of 300-1100 individuals, with approximately 70% adult workers. The structure of their nests is relatively simple, resembling that of the most studied species in North America, though less developed in depth and total number of chambers, probably due to the smaller number of workers per colony. These characteristics (small colony size and relatively simple nests) are considered typical of the South American Pogonomyrmex ants, which distinguish them from most of the studied North American species in the genus.

Keywords : Pogonomyrmex inermis; Pogonomyrmex rastratus; Pogonomyrmex mendozanus; Colony size; South America.

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