Genetic structures of huge ant colonies, with reference to mechanism for maintaining the polyethism in eusocial insects

我研究了叶蚁、水蚁和三种拥有超级蚁群或巨大蚁群的军蚁。在日本北部石垣海岸的一个超群体中，用四个微卫星DNA引物测量了它们的亲缘关系。巢内关联度为0.248~0.484，巢间关联度为0.148~0.343。巢间亲缘关系与巢间距离无关，表明遗传粘性的缺失被认为是维持超群体的最终机制。我收集了东南亚、新几内亚和澳大利亚的30个种群的斑潜蝇种群，利用线粒体cytb基因分析了它们的系统发育。系统发育分析表明，第一次分化发生在其历史的早期阶段，即亚洲人、澳大利亚人和苏拉威人群体的崛起。这一组合与更新世冰期陆块的分布基本一致。此后，每个种群似乎独立地分化成每个陆地上的现有种群。我还研究了原始蚂蚁部落Amblyoponini中的游牧蚂蚁Onychymrmex hedleyi的物候和形态，它被认为是军蚁行为进化研究的重要内容。它们的行为与高等军蚁的不同之处在于：它们的群体规模似乎是所有军蚁中最小的；群体迁移的方向是不规则的，由长距离迁移和短距离迁移组成。

I made research on such ant species as Formica yessensis, Oecophylla smaragdina and three army ants which have supercolonies or huge colonies. In a supercolony of F.yessensis on Ishikari Coast, northern Japan, the relatedness was measured using four microsatellite DNA primers. The within-nest relatedness was from 0.248 to 0.484 while the between-nest relatedness was from 0.148 to 0.343. The between-nest relatedness was not correlated with between-nest distance, suggesting the absence of genetic viscosity which had been considered as the ultimate mechanism for maintaining the supercolonies.I collected Oecophylla smaragdina colonies from 30 local populations in South-East Asia, New Guinea and Australia and analyzed the phylogeny using mitochondrial cyt b gene. The Phylogenetic analysis suggested that the first divergence occurred In early stage of their history in which the Asian, Australian and Sulawesian groups rose. This grouping was almost coincident with the distribution of land-mass In glacial periods In Pleistocene. Thereafter, each group seemed to have Independently diverged into present populations on each landmass.I also studied the phenology and morphology of the ponerine nomadic ant Onychomyrmex hedleyi which belongs to the primitive ponerine ant tribe Amblyoponini and has been considered to be important for evolutionary studies of army ant behavior. Their behavior was different from that of higher army ants as follows : the colony size seems the smallest of all army ants ; the direction of colony migration is irregular, consisting of long-distance migration and short-distance migration.