Mating system, population genetics, and phylogeography of the devil's garden ant, Myrmelachista schumanni, in the Peruvian Amazon

摘要

Devil's gardens are a remarkable feature of Amazonian rainforests. These clearings result from the cultivation of ant-plants by their symbiotic ant, Myrmelachista schumanni. Each devil's garden is inhabited by a single M. schumanni colony, often with millions of workers and thousands of queens. Through a combination of field surveys and microsatellite genotyping, we examined M. schumanni colony structure, mating system, dispersal, and phylogeography. We discovered that the reproduction of M. schumanni is weakly seasonal, exhibits facultative polyandry, and involves split sex ratios potentially leading to sex-biased dispersal. Surprisingly, we observed only very weak clustering of genetic variation, either within or between devil's gardens. We hypothesize that the apparent absence of geographical structure results from the unusually high level of genetic differentiation between colonies. This study adds intriguing observations to the scarce literature about the reproduction and phylogeography of Amazonian ants.