2001 Fiscal Year Final Research Report Summary
Studies on factors biasing the primary sex ratio toward females in the oriental tea tortrix, Homona magnanima (Lepidoptera : Trotricidae)
| Project/Area Number |
12660052
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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 |
蚕糸・昆虫利用学
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| Research Institution | Tokyo University of Agriculture and Technology |
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Principal Investigator |
KUNIMI Yasuhisa Department of Applied Biological Science, Faculty of Agriculture, Tokyo University of Agriculture and Technology, Professor, 農学部, 教授 (50195476)
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| Co-Investigator(Kenkyū-buntansha) |
MAKAI Madoka Department of Applied Biological Science, Faculty of Agriculture, Tokyo University of Agriculture and Technology, Professor, 農学部, 助手 (60302907)
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| Project Period (FY) |
2000 – 2001
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| Keywords | Homona magnanima / Male-killing / Wolbachia / Sex-ratio distorters / Tumor / Virus-like particles / Horizontal transmission / Vertical transmission |
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| Research Abstract |
A female-biased sex ratio was found in the oriental tea tortrix, Homona magnanima (Lepidoptera : Tortricidae), in Tsukuba, Ibaraki, Japan. There was no difference in mean egg hatch between the all-female and normal strains. Greater than 50% mortality was observed in the all-female strain larvae, suggesting that female-only broods are produced as a result of late male-killing. The female-biased sex ratio was maternally inherited and maintained, even when females were backcrossed with males of the normal strain, thus implicating cytoplasmic parasitism as its cause. The phenomenon was persistent in the presence of antibiotics, and was not due to infection by agents that cause other male-killing phenomena, such as Rickettsia, Wolbachia, Spiroplasma, or protozoan parasites. When a homogenate of dead male larvae of the all-female strain was inoculated in normal strain larvae, this male-killing trait was transmitted to the next generation ; thus, its causative agent is likely transmitted horizontally as well.
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