Colony structure in three species of the ant genus Myrmecia

Ants of the genus Myrmecia have retained many biological traits that are considered to be basal in the family\ud Formicidae. Studying these ants may provide valuable insight into the early stages of formicid social\ud evolution. Using microsatellites, we investigated colony structure in three Myrmecia species, viz. M. brevinoda, M. pilosula, and a newly discovered cryptic species of the M. pilosula complex, Myrmecia sp. We observed, as a first ever for the genus Myrmecia, the co-occurrence of polydomy, polygyny and polyandry, in all three species. Mating frequencies of queens varied strongly within species, but the maximum frequencies were high in all of them, ranging from 9 to 12. Queens within colonies were lowly related in M. brevinoda and M. pilosula, but unrelated in Myrmecia sp. In M. pilosula and M. sp., the colony founding mode could be\ud budding, as indicated by Mantel tests. Our data for M. brevinoda are in support of the "genetic-variability"\ud hypothesis that polygyny and polyandry should be negatively correlated due to their costs and the benefits of\ud the resulting genetic variability