| Project/Area Number |
16570024
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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 |
Ecology/Environment
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| Research Institution | National Institute for Environmental Studies |
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Principal Investigator |
NAGATA Hisashi National Institute for Environmental Studies, Environmental Biology Division, Senior Researcher, 生物圏環境研究領域, 主任研究員 (00202226)
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| Project Period (FY) |
2004 – 2006
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| Project Status |
Completed (Fiscal Year 2006)
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| Budget Amount *help |
¥2,700,000 (Direct Cost: ¥2,700,000)
Fiscal Year 2006: ¥800,000 (Direct Cost: ¥800,000)
Fiscal Year 2005: ¥800,000 (Direct Cost: ¥800,000)
Fiscal Year 2004: ¥1,100,000 (Direct Cost: ¥1,100,000)
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| Keywords | Immunity / prevalence / avian maralia / avian trypanosome / female choice / Great Reed Warbler / mating success / immunocompetence handicap / 暴露型ハンディキャップ / 血液寄生虫 / 繁殖成功度 / トリパノゾーマ / 曝露型ハンディキャップ / 一夫多妻 |
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| Research Abstract |
Polygynous species are supposed to expose higher pressure of sexual selection than monogamous one. The immunocompetence handicap hypothesis suggests that the immune system competes for resources with sexually selected one. I tested whether Polygynous males have showed higher immunity as suggested by this hypothesis. Cell-mediated immune response (CMI), as measured by the phytohaemagglutinin (PHA) assay, was measured in relation to mating success and the prevalence of blood parasites in great reed warblers Acrocephalus arundinaceus at Lake Kasumigaura between 2004 and 2006. The prevalence of blood parasites was relatively high in the studied population. 26% of individuals were infected with avian maralia, and 10% of individuals were infected with avian trypanosome. The infections of blood parasites did not affect any female preferences though females infected with avian malaria tended to suffer from higher nest predation. PHA responses were unrelated to the prevalence of blood parasites. Polygynous males have higher PHA response than monogamous ones for after second year birds. Thus, CMI response might be closely correlated to male quality. Generalized linear mixed model showed that mating success of males was expalained by their age, the imminity, and a compounded effect between immunity and their age. As yearlings have higher PHA response than older birds, repeated measurements from the same individual across years are necessary to resolve it.
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