| Project/Area Number |
18K19361
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| Research Category |
Grant-in-Aid for Challenging Research (Exploratory)
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| Allocation Type | Multi-year Fund |
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| Review Section |
Medium-sized Section 45:Biology at organismal to population levels and anthropology, and related fields
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| Research Institution | Shinshu University |
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Principal Investigator |
Tojo Koji 信州大学, 学術研究院理学系, 教授 (30377618)
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| Project Period (FY) |
2018-06-29 – 2021-03-31
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| Project Status |
Completed (Fiscal Year 2020)
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| Budget Amount *help |
¥6,240,000 (Direct Cost: ¥4,800,000、Indirect Cost: ¥1,440,000)
Fiscal Year 2020: ¥1,040,000 (Direct Cost: ¥800,000、Indirect Cost: ¥240,000)
Fiscal Year 2019: ¥2,210,000 (Direct Cost: ¥1,700,000、Indirect Cost: ¥510,000)
Fiscal Year 2018: ¥2,990,000 (Direct Cost: ¥2,300,000、Indirect Cost: ¥690,000)
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| Keywords | 昆虫 / 胚発生 / 胎生 / カゲロウ / 適応放散 / 卵黄タンパク質 / 栄養供給 / 栄養の再吸収 / 繁殖システム / 発生 / 新規の胎生 / 卵胎生 / 人工授精 / ハンドペアリング / 進化 |
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| Outline of Final Research Achievements |
Cloeon dipterum is a globally distributed mayfly species. The reasons for achieving such widespread distribution have been considered to be adaptation to various aquatic environments including artificial pools, and also acquisition parthenogenetic ability and ovoviviparity.
In this study, we conducted phylogeographic analyses of this mayfly, and clarified that the populations of the Japanese Archipelago and the Korean Peninsula are derivative and peculiar intra-specific lineage. In addition, it was revealed that the lineage of the Japanese archipelago does not have parthenogenetic ability and their developmental patterns are extremely peculiar. It was suggested that the embryogenesis of this mayfly may not be an ovoviviparous type, but an viviparous type that receives nutrition from the mother. Furthermore, it was suggested that C. dipterum may be a novel viviparous type that is different from any type of insect viviparity such as previously known.
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| Academic Significance and Societal Importance of the Research Achievements |
地球上で最も種多様性が高い昆虫類には、多様な形態や生態がよく知られている。しかしながら、系統の存続に強く影響する繁殖システムについては保存性が高く、一部の特殊な昆虫類に、卵胎生や胎生が知られる程度で、基本的には卵生が大多数を占めている。
この研究で注目したフタバカゲロウは最も身近な昆虫の一種で、学校の水泳プールなどにも生息し、北半球を中心に汎世界的に分布する普通種であるが、少なくとも本種の日本列島系統では、新規「胎生」という、特殊な発生様式をもつことが明らかとなった。これは、昆虫における多様性の理解や進化における神秘性に一石を投じる成果と言える。
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