2018 Fiscal Year Final Research Report
Why did female penis evolved in a group of cave isnects
| Project/Area Number |
15H04409
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| Research Category |
Grant-in-Aid for Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Biodiversity/Systematics
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| Research Institution | Hokkaido University |
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Principal Investigator |
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| Co-Investigator(Kenkyū-buntansha) |
吉冨 博之 愛媛大学, ミュージアム, 准教授 (10542665)
上村 佳孝 慶應義塾大学, 商学部(日吉), 准教授 (50366952)
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| Research Collaborator |
Ferreira Rodrigo L.
Lienhard Charles
Blanke Alexander
Johnson Kevin P.
Cameron Stephen L.
YAO Izumi
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| Project Period (FY) |
2015-04-01 – 2019-03-31
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| Keywords | トリカヘチャタテ / 性選択 / 交尾器進化 / 機能形態学 / 雌ペニス |
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| Outline of Final Research Achievements |
The female penis, which is protrudable and inserted into the male vagina-like cavity during copulation to receive semen, is thought to have evolved independently twice in the tribe Sensitibillini, once in the Brazilian Neotrogla and once in the African Afrotrogla. This strongly suggests that there are some factors unique to Sensitibillini that have facilitated female penis evolution. The female-female competition for nutritious semen, the oligotrophic environment, and the twin insemination slots with switching valve are considered to be the driving factors for female penis evolution. Additionally, the following factors are considered responsible for relaxing the constraint against female penis evolution: pre-existence of the female-above mating position, the elongated duct connecting the female pre-penis with the sperm storage organ, and the small male genital cavity accepting the female genital tubercle bearing the opening of this duct.
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| Free Research Field |
昆虫体系学
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| Academic Significance and Societal Importance of the Research Achievements |
本申請課題の背景となった研究成果が，イグ・ノーベル賞を受賞した．本プロジェクトが，科学の面白さや基礎研究の重要性を普及させる大きな役割を果たした．
学術的には，雌ペニスに匹敵するような大規模な進化的革新は動物界全体を見ても滅多に生じていないため，雌ペニスは進化的新奇性の研究対象として注目される．また雌ペニスを持つ生物は，性選択に関わる諸問題に，通常の交尾器を持つ生物を使った研究とは異なるアプローチによる検証を可能にする．このような視点から，なぜペニスは主に雄に進化したのか，と言った問も可能となる．
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