Synergetic effects of community-level phenology of intermediate hosts and definitive hosts on the probability of trophic transmission in a nematomorph parasite

2022 Fiscal Year Final Research Report

• Project/Area Number: 19H03304
• Research Category: Grant-in-Aid for Scientific Research (B)
• Allocation Type: Single-year Grants
• Section: 一般
• Review Section: Basic Section 45040:Ecology and environment-related
• Research Institution: Kyoto University (2021-2022); Kobe University (2019-2020)
• Principal Investigator: Sato Takuya 京都大学, 生態学研究センター, 准教授 (30456743)
• Co-Investigator(Kenkyū-buntansha): 渡辺 勝敏 京都大学, 理学研究科, 准教授 (00324955) ; 瀧本 岳 東京大学, 大学院農学生命科学研究科(農学部), 准教授 (90453852)
• Project Period (FY): 2019-04-01 – 2023-03-31
• Keywords: ハリガネムシ / 感染症 / 群集フェノロジー / R0

Outline of Final Research Achievements

We study phenological transmission of a nematomorph infecting intermediate hosts of aquatic insects whose emergence transfers cysts to definitive hosts of ground-dwelling beetles that feed on aquatic insect adults. Field observations found that asynchronous emergence of cyst-carrying aquatic insects occurred, providing a long time window for potential transmission. Ground-dwelling beetles that the nematomorph could infest occurred mostly during the first half of the transmission window, indicating that many of the late transferred cysts were wasted. Model simulations showed that asynchronous emergence among aquatic insect hosts stabilized transmission although a broadened window for potential transmission could increase unsuccessful transmission. These results suggest that phenological diversity of parasite hosts can synergistically determine the efficiency and stability of transmission and shed light on the roles of apparent wastes of unsuccessful transmission.

Free Research Field

群集生態学

Academic Significance and Societal Importance of the Research Achievements

生物多様性による感染症の制御は基礎科学のみでなく、社会福祉においても極めて重要な課題である。先行研究では、宿主の種多様性による希釈効果と増幅効果のいずれかが寄生者を制御するという前提の下で研究が進められてきた。これに対して、本研究では、中間宿主と終宿主の両方に種多様性が存在することに着目して、両者の群集レベルでのフェノロジーの一致度が感染動態にもたらす影響を体系的に理解するフレームワークを世界に先駆けて構築した。