Effects of native nematode and insect vectors on the range expansion of invasive nematode

2017 Fiscal Year Final Research Report

• Project/Area Number: 26292080
• Research Category: Grant-in-Aid for Scientific Research (B)
• Allocation Type: Partial Multi-year Fund
• Section: 一般
• Research Field: Forest science
• Research Institution: The University of Tokyo
• Principal Investigator: Togashi Katsumi 東京大学, 大学院農学生命科学研究科(農学部), 教授 (30237060)
• Co-Investigator(Kenkyū-buntansha): 杉本 博之 山口県農林総合技術センター, 林業技術部林業研究室, 専門研究員(総括) (00522244) ; 松永 孝治 国立研究開発法人森林研究・整備機構, その他部局等, 主任研究員 等 (40415039) ; 柳澤 賢一 長野県林業総合センター, 育林部, 研究員 (90755191) ; 岡田 充弘 長野県林業総合センター, 育林部, 主任研究員 (90450816)
• Research Collaborator: Shimizu Kayo
• Project Period (FY): 2014-04-01 – 2018-03-31
• Keywords: 森林科学 / 侵入生物 / マツ材線虫病 / マツノザイセンチュウ / ニセマツノザイセンチュウ / マツノマダラカミキリ / カラフトヒゲナガカミキリ / Allee効果

Outline of Final Research Achievements

Pine wilt disease system is composed of an alien pathogenic nematode, the insect vector, and the pine host. The disease has been killing a lot of pine trees and causing the outbreak of insect vector. Hybridization between the pathogenic nematodes and native non-pathogenic nematodes occurred at the front of the disease incidence range, resulting in introgression hybridization which leads to adaptive evolution for the pathogenic nematode. The outbreak of insect vectors made the dispersal have no relation to the reproductive ability, leading to the expansion rate of disease incidence range more quickly than the pre-outbreak densities. It is predicted that low densities of the insect vector cannot induce the disease epidemic (Allee effect) even when the host trees are above a density under which the epidemics do not occur. The Allee effect was verified in the field, suggesting that controlling the host tree density and vector density may inhibit the disease epidemics.

Free Research Field

森林動物学