Ecological impacts of non-native pasture grasses associated with mutualistic endophytes and their risk management

• Project/Area Number: 15K07703
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Research Field: Animal production science
• Research Institution: Shizuoka University
• Principal Investigator: Sawada Hitoshi 静岡大学, 農学部, 教授 (10183831)
• Co-Investigator(Kenkyū-buntansha): 山下 雅幸 静岡大学, 農学部, 教授 (30252167)
• Project Period (FY): 2015-04-01 – 2019-03-31
• Project Status: Completed (Fiscal Year 2018)
• Budget Amount: ¥4,940,000 (Direct Cost: ¥3,800,000、Indirect Cost: ¥1,140,000); Fiscal Year 2018: ¥910,000 (Direct Cost: ¥700,000、Indirect Cost: ¥210,000); Fiscal Year 2017: ¥910,000 (Direct Cost: ¥700,000、Indirect Cost: ¥210,000); Fiscal Year 2016: ¥910,000 (Direct Cost: ¥700,000、Indirect Cost: ¥210,000); Fiscal Year 2015: ¥2,210,000 (Direct Cost: ¥1,700,000、Indirect Cost: ¥510,000)
• Keywords: 牧草 / 外来生物 / 生態学 / 草地生態

Outline of Final Research Achievements

Non-native pasture plants can escape from originally planting sites to often form naturalized populations. Thus, risk management for those is urgently needed, whereas they are industrially important. We focused on those with mutualistic endophytes, conducting a literature survey and performing both laboratory and outdoor experiments. Information on Italian ryegrass and tall fescue was widely collected both within and outside Japan to grasp their invasions and potential impacts. Laboratory feeding experiments using the emma field crickets suggested that endophyte-infecting Italian ryegrass seeds could decrease the performance of both adults and larvae of the crickets and reduce egg production. We partially elucidated the factors responsible for the changes in endophyte infection rate of host populations.

Academic Significance and Societal Importance of the Research Achievements

牧草は我が国の粗飼料生産の基盤であるが、その多くは外来種である。しばしば野生化集団を形成し、外来種としてのリスク管理が求められる。そこで、エンドファイトと共生する草種(特にイタリアンライグラスとトールフェスク)に焦点を当て、国内外の情報を広く収集し、被害の実態と可能性を把握した。さらに種子食昆虫への影響を評価した。野生化集団のエンドファイト感染率を上昇させうる要因と低下させる要因を部分的に解明した。

Research Products

• [Journal Article] グラスエンドファイトが種子食昆虫および宿主草種へ及ぼす影響 (2019)
  • Author(s): 山下雅幸・澤田 均
  • Journal Title: 日本草地学会誌 Volume: 64 Pages: 272-275
  • NAID: 130007680146
  • Peer Reviewed
• [Journal Article] Preferences of male and female field crickets for Italian ryegrass and white clover seeds (2018)
  • Author(s): Hitoshi Sawada, Tatsunori Tanaka, Minoru Ichihara, masayuki Yamashita
  • Journal Title: Proceedings of the 7th Japan-China-Korea Grassland Conference Volume: 1 Pages: 92-93
  • Peer Reviewed
• [Presentation] Preferences of male and female field crickets for Italian ryegrass and white clover seeds (2018)
  • Author(s): Hitoshi Sawada, Tatsunori Tanaka, Minoru Ichihara, Masayuki Yamashita
  • Organizer: The 7th Japan-China-Korea Grassland Conference
  • Int'l Joint Research
• [Presentation] ライグラス類の野生化とエンドファイト共生に関する研究 (2018)
  • Author(s): 山下雅幸
  • Organizer: 2018年度日本草地学会熊本大会
  • Invited
• [Presentation] Preferences of male and female field crickets for Italian ryegrass and white clover seeds (2018)
  • Author(s): Sawada H., Tanaka T., Ichihara M. and Yamashita M.
  • Organizer: The 6th Japan-China-Korea Grassland Conference
  • Int'l Joint Research
• [Presentation] グラスエンドファイトが種子食昆虫および宿主草種へ及ぼす影響 (2017)
  • Author(s): 山下雅幸・澤田 均
  • Organizer: 日本草地学会
  • Place of Presentation: 弘前大学（青森県弘前市）
  • Year and Date: 2017-03-22