2002 Fiscal Year Final Research Report Summary
Genetic structures of huge ant colonies, with reference to mechanism for maintaining the polyethism in eusocial insects
| Project/Area Number |
13640623
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
生態
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| Research Institution | HOKKAIDO UNIVERSITY |
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Principal Investigator |
HIGASHI Seigo Hokkaido University, Graduate School of Environmental Earth Science, 大学院・地球環境科学研究科, 教授 (90133777)
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| Project Period (FY) |
2001 – 2002
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| Keywords | supercolony / genetic viscosity / relatednes / molecular phylogeny / army ant / weaver ant |
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| Research Abstract |
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.
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