Dynamical theory of switching predation based on chemical substances arising learning behaviors in the parasitic wasp

2019 Fiscal Year Final Research Report

• Project/Area Number: 17H03731
• Research Category: Grant-in-Aid for Scientific Research (B)
• Allocation Type: Single-year Grants
• Section: 一般
• Research Field: Ecology/Environment
• Research Institution: The University of Tokyo
• Principal Investigator: SHIMADA Masakazu 東京大学, 大学院総合文化研究科, 名誉教授 (40178950)
• Co-Investigator(Kenkyū-buntansha): 松山 茂 筑波大学, 生命環境系, 講師 (30239131) ; 笹川 幸治 千葉大学, 教育学部, 准教授 (30647962)
• Project Period (FY): 2017-04-01 – 2020-03-31
• Keywords: 寄生蜂ゾウムシコガネコバチ / 化学コミュニケーション / 行動生態学 / 匂い学習と選好性 / スィッチング捕食 / 3者系の共存安定化 / カイロモン / 馴れ

Outline of Final Research Achievements

We determined kairomones that the parasitic wasp uses and learns to find a common host species for oviposition in one parasitoid (Anisopteromalus calandrae) and two bruchine hosts (Callosobruchus chinensis, C. maculatus)
In the experimental system. The parasitoid performed frequency-dependent predation on two host species with olfactory cues and switched the preference depending on their abundance. We collected and extracted footprint chemicals of each host, and determined their chemical structures using GC-MS. Kairomones of C. chinensis were mainly 11-MeC27, and those of C. maculatus were primarily 9-MeC27, 3-MeC29, 9,13-diMeC29. When we synthesized the four substances and presented them alone or in a blend to wasps, we were able to reproduce learning and memory effects, inducing wasps’ host parasitizing behaviors. We also observed the ability of wasps to habituate kairomones in order to explore a mechanism that allows host switching.

Free Research Field

行動生態学

Academic Significance and Societal Importance of the Research Achievements

学術的意義は、多様に変化する複数の環境（既知宿主と未知宿主）に適応可能な寄生性の天敵昆虫の学習行動システムを理解する上で、行動生態学と神経行動学を結ぶ学問を構築し、心理学的視点の重要性を示した。　社会的意義としては、天敵を利用した生物防除の理論と実証に大いに役立つ。生物多様性の意義や重要性の理解に役立つ。また、生物多様性の保全方法について科学的な視点から具体的な提言を行なえる。