Post-mating changes in host finding behavior and olfactory reception of Pieris rapae females

2018 Fiscal Year Final Research Report

• Project/Area Number: 16K08099
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Research Field: Insect science
• Research Institution: Hiroshima University
• Principal Investigator: Omura Hisashi 広島大学, 統合生命科学研究科, 准教授 (60335635)
• Co-Investigator(Kenkyū-buntansha): 藤井 毅 東京大学, 大学院農学生命科学研究科(農学部), 特任助教 (30730626)
• Research Collaborator: ISHIKAWA Yukio
• Project Period (FY): 2016-04-01 – 2019-03-31
• Keywords: 植食性昆虫 / モンシロチョウ / 寄主選択 / 植物揮発性成分 / 幼虫糞 / 触角感受性 / 交尾 / 嗅覚

Outline of Final Research Achievements

This study addressed the olfactory-guided host finding of Pieris rapae females and the post-mating changes in its behavior and olfactory reception. Mated females were more responsive to host plant volatiles than virgin females, in which the treatment of plant models with synthetic blends of cabbage leaf increased the number of landing on plant models by mated females. Since antennal responsiveness to host plant volatiles was similar between mated and virgin females, such behavioral enhancement of mated females might be attributed to post-mating changes in central nervous system involved in olfactory reception. Host-finding females showed weak repellency against larval frass odor although actual repellents could not be identified, in which virgin females were more sensitive than mated females. Quantitative RNA analyses revealed that female antennae possessed extremely low amounts of RNA and that 11 and 18 RNA genes overexpressed in female thorax and eggs, respectively, after mating.

Free Research Field

化学生態学

Academic Significance and Societal Importance of the Research Achievements

昼行性のチョウは視覚的手がかりを利用して遠隔的な寄主探索をおこなうと考えられてきた。本研究では、母チョウが視覚のみならず嗅覚も利用することを実験的に証明し、寄主探索の手がかりとなる植物由来のカイロモンを同定するとともに、幼虫糞の匂いが弱いながらも雌を忌避することを見いだした。これらの知見は、アブラナ科の重要害虫であるモンシロチョウの行動を匂い物質で制御するための基礎情報であり、新規防除法開発のシーズになりうる。また、雌成虫の行動は交尾後ダイナミックに変化しており、行動生理学的な視点においても、交尾前の雌の防除および交尾の攪乱がより重要であることが示唆された。