High inter-colonial variation in worker nestmate relatedness and diverse social structure in a desert ant from Mongolia

摘要

Ants of the genus Cataglyphis have a broad distribution and display a remarkable degree of variation in life-history traits between species, making them an excellent model system for comparative studies, but the biology of many key species remains unknown. In this study we present the first data on the most easterly distributed member of the genus, Cataglyphis aenescens from Mongolia. We collected workers and brood from 40 colonies from a population located on the outskirts of Sainshand, in south-eastern Mongolia, and genotyped them with microsatellite markers. In the population studied, our data strongly suggest that this species is monodomous, facultatively polygynous and exhibits a low level of polyandry compared to most other Cataglyphis species. The large worker size variation observed within colonies was not related to the level of genetic relatedness. We found no evidence of genetic isolation by distance based on workers and no evidence of thelytokous reproduction by queens as occurs in some other species. Although the sociogenetic organisation of this species could not be completely resolved, it is clear that there is a sharp contrast between C. aenescens and its closest congener, C. cursor. This underlines the variability of various life-history traits exhibited within the group, and we discuss the new findings in light of the available biological and phylogenetic information.