2023 Fiscal Year Final Research Report

Evolution of resistant females and mechanisms of emergence of promiscuous females and countermeasures

Research Project

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Project/Area Number	21K19116
Research Category	Grant-in-Aid for Challenging Research (Exploratory)
Allocation Type	Multi-year Fund
Review Section	Medium-sized Section 39:Agricultural and environmental biology and related fields
Research Institution	Okayama University
Principal Investigator	Miyatake Takahisa 岡山大学, 環境生命自然科学学域, 教授 (80332790)
Co-Investigator(Kenkyū-buntansha)	安井行雄香川大学, 農学部, 准教授 (30325328) 日室千尋琉球大学, 農学部, 協力研究員 (60726016) 矢嶋俊介東京農業大学, 生命科学部, 教授 (90301548)
Project Period (FY)	2021-07-09 – 2024-03-31
Keywords	不妊化法 / 害虫根絶 / 進化実験 / 交尾前性選択 / 交尾後性選択
Outline of Final Research Achievements	In 10-generation evolutionary experiment using Tribolium castaneum, we established treatment lines in which generations were linked by cohabitation with infertile males and control lines in which generations were linked without cohabitation with infertile males. Females in the treatment lines mated significantly more frequently than females in the control lines. On the other hand, pre-mating sexual selection, the ability of females to distinguish infertile males, did not evolve in this evolutionary experiment. Next, we examined "post-mating sexual selection" by measuring the hatchability of eggs laid by females of both strains, and found that females of the treatment strain were able to identify the sperm of infertile males. Next, there was no difference in pre-mating sexual selection between weevils from Kikaijima Island, where infertile males were released and those from Naha, where infertile males were not released, but the number of mating attempts differed.
Free Research Field	昆虫科学
Academic Significance and Societal Importance of the Research Achievements	メスが不妊オスを識別できるかは誰も挑戦していない課題で①【抵抗性メスの進化】と②【多オス交尾メスの進化】のどちらになるかは探索的性質が強く芽生え期の研究計画である。実験の結果、①であれば低線量や分割照射することで不妊オスに対するメスの識別（抵抗性）の進化を抑制する（低線量なのでオスの交尾行動に異常が見られずメスは外見で識別できない）技術を確立して根絶が達成できる。②であればオス側の戦略として野外において進化してきた強い再交尾抑制物質を射精するオスを選抜することで乱婚性メスの進化防止につなげる技術開発につながる。本課題は侵入害虫の駆除方法において野生集団の進化特性を理解する重要性を明らかにする。