| Project/Area Number |
22K05667
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Multi-year Fund |
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| Section | 一般 |
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| Review Section |
Basic Section 39050:Insect science-related
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| Research Institution | Obihiro University of Agriculture and Veterinary Medicine |
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Principal Investigator |
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| Co-Investigator(Kenkyū-buntansha) |
菊池 義智 国立研究開発法人産業技術総合研究所, 生命工学領域, 研究グループ長 (30571864)
日室 千尋 琉球大学, 農学部, 協力研究員 (60726016)
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| Project Period (FY) |
2022-04-01 – 2025-03-31
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| Project Status |
Completed (Fiscal Year 2024)
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| Budget Amount *help |
¥4,160,000 (Direct Cost: ¥3,200,000、Indirect Cost: ¥960,000)
Fiscal Year 2024: ¥1,040,000 (Direct Cost: ¥800,000、Indirect Cost: ¥240,000)
Fiscal Year 2023: ¥1,300,000 (Direct Cost: ¥1,000,000、Indirect Cost: ¥300,000)
Fiscal Year 2022: ¥1,820,000 (Direct Cost: ¥1,400,000、Indirect Cost: ¥420,000)
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| Keywords | イモゾウムシ / 共生細菌 / ナルドネラ / Eyscepes postfasciatus / 性淘汰 / 性的対立 / 配偶行動 / 交尾行動 / 性選択 / 交尾器 |
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| Outline of Research at the Start |
イモゾウムシでは，外骨格や交尾器の硬化に必要なクチクラ形成を共生細菌ナルドネラに依存する．外骨格や交尾器は，体サイズが強く関与する雌による選択や精子輸送で重要で，共生細菌が宿主の性選択に直接関与することを示す．本研究では，クチクラ形成を操作し宿主の性的対立を緩和し，交尾器挿入時の雌内部構造の観察や雄由来物質輸送を定量化することで，宿主の配偶行動での共生細菌の役割を明らかにする．
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| Outline of Final Research Achievements |
In Euscepes postfasciatus, the formation of cuticle, which is essential for the hardening of the exoskeleton and copulatory organs, depends on the symbiotic bacterium Naldonella. Cuticle plays a crucial role in female choice and sperm transport, indicating that symbiotic bacteria directly influence the host's sexual selection. In this study, we manipulated cuticle formation to mitigate sexual conflict in the host species, allowing for the observation of the female's internal structure during copulatory organ insertion and the quantification of male-derived substance transport. The results showed that males in treated individuals with symbiotic bacteria Nardella removed had smaller spines compared to controls, and the extent of damage to female genitalia (scarring) was also reduced. Additionally, the number of transported sperm was found to decrease. These findings strongly suggest that symbiotic bacteria play a role in driving sexual conflict in this species.
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| Academic Significance and Societal Importance of the Research Achievements |
昆虫の外骨格は，コウチュウに硬さをもたらす本質的な形質であると同時に，カタチ・色彩・サイズを通じて個体に変異をもたらしており，性選択とも関連の深い形質でもある．従来，性選択は異性をめぐる競争を通じて生じる進化と定義され，多くの研究が種内の雌雄の相互作用を研究対象としてきた．しかし，本研究で我々が着目するイモゾウムシとナルドネラの系では，共生細菌が宿主昆虫の外骨格の質的変化をもたらし，性的対立を作出し駆動させることが明らかになった．このことは，従来の理解とは全く異なる性選択の機構が存在することを示している．
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