van der Hammen T, Pedersen J S, Boomsma J J
Department of Population Ecology, Zoological Institute, University of Copenhagen, Universitetsparken 15, DK-2100 Copenhagen, Denmark.
Heredity (Edinb). 2002 Aug;89(2):83-9. doi: 10.1038/sj.hdy.6800098.
Many ant species have independently evolved colony structures with multiple queens and very low relatedness among nestmate workers, but it has remained unclear whether low-relatedness kin structures can repeatedly arise in populations of the same species. Here we report a study of Danish island populations of the red ant Myrmica sulcinodis and show that it is likely that such repeated developments occur. Two microsatellite loci were used to estimate genetic differentiation (F(ST)) among three populations and nestmate relatedness within these populations. The F(ST) values were highly significant due to very different allele frequencies among the three populations with relatively few common alleles and relatively many rare alleles, possibly caused by single queen foundation and rare subsequent immigration. Given the isolation of the islands and the low investment in reproduction, we infer that each of the populations was most likely established by a single queen, even though all three extant populations now have within-colony relatedness 95%), and the genetic differentiation of nests showed a significantly positive correlation with the distance between them. Both male-biased sex-ratio and genetic viscosity are expected characteristics of populations where queens have very local dispersal and where new colonies are initiated through nest-budding. Based on a comparison with other M. sulcinodis populations we hypothesise a distinct succession of population types and suggest that this may be a possible pathway to unicoloniality, ie, development towards a complete lack of colony kin structure and unrelated nestmate workers.
许多蚁种都独立进化出了具有多个蚁后的蚁群结构，且同巢工蚁之间的亲缘关系非常低，但同一物种的种群中低亲缘关系的亲属结构是否会反复出现仍不清楚。在此，我们报告一项对丹麦岛屿上红蚁Myrmica sulcinodis种群的研究，并表明这种反复发展很可能会发生。我们使用两个微卫星位点来估计三个种群之间的遗传分化（F(ST)）以及这些种群内同巢蚁的亲缘关系。由于三个种群之间等位基因频率差异很大，共同等位基因相对较少，稀有等位基因相对较多，F(ST)值非常显著，这可能是由单蚁后奠基以及随后罕见的迁入造成的。鉴于岛屿的隔离状态以及繁殖投入较低，我们推断每个种群很可能都是由单个蚁后建立的，尽管所有三个现存种群现在巢内亲缘关系都很高（平均为95%），而且巢穴的遗传分化与它们之间的距离呈显著正相关。雄性偏向的性别比例和遗传粘性都是蚁后扩散范围非常有限且新蚁群通过分巢产生的种群的预期特征。通过与其他M. sulcinodis种群进行比较，我们推测出种群类型的独特演替，并认为这可能是通向单巢性的一条可能途径，即朝着完全缺乏蚁群亲属结构和无亲缘关系的同巢工蚁发展的过程。
