How does the cryptic local adaptation to closely related plants promote the speciation of phytophagous insects?

2022 Fiscal Year Final Research Report

• Project/Area Number: 19K06803
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Review Section: Basic Section 45030:Biodiversity and systematics-related
• Research Institution: Yamagata University
• Principal Investigator: Fujiyama Naoyuki 山形大学, 理学部, 教授 (90360958)
• Co-Investigator(Kenkyū-buntansha): 松林 圭 九州大学, 基幹教育院, 助教 (60528256) ; 横山 潤 山形大学, 理学部, 教授 (80272011)
• Project Period (FY): 2019-04-01 – 2023-03-31
• Keywords: 植食性昆虫 / 寄主植物 / 局所適応 / 生息場所隔離 / 移入者の生存不能 / ヤマトアザミテントウ / アザミ類

Outline of Final Research Achievements

The herbivorous ladybird beetle Henosepilachna niponica and its host thistles (Cirsium spp.) were investigated as a model. Various degree of local adaptation regarding the host preference for and the developmental ability on different species/populations of thistles was detected. The estimation of strength of respective reproductive barriers resulting from the local adaptation revealed that the reproductive isolation among beetle populations was not symmetric but approximate value was 0.5 on average. Hence, the beetle populations were considered to be under the process of speciation via cryptic local adaptation.

Free Research Field

進化生態学

Academic Significance and Societal Importance of the Research Achievements

近縁な寄主植物に対して生じる昆虫の局所適応は、隠蔽的に生じることから、その普遍性や意義に関する理解が大きく遅れている。本研究では、そのような隠蔽的な局所適応がどのように生じているかを詳細に明らかにしたとともに、局所適応がどの程度昆虫集団間の生殖的障壁の発達（＝種分化）を促しているかを定量的に評価することができた。