The evolution of biological hierarchy reinforced by intraspecific parasitism: a test with social insects

2023 Fiscal Year Final Research Report

• Project/Area Number: 21H02537
• Research Category: Grant-in-Aid for Scientific Research (B)
• Allocation Type: Single-year Grants
• Section: 一般
• Review Section: Basic Section 45020:Evolutionary biology-related
• Research Institution: The University of Tokyo
• Principal Investigator: Dobata Shigeto 東京大学, 大学院総合文化研究科, 准教授 (50714995)
• Co-Investigator(Kenkyū-buntansha): 北條 賢 関西学院大学, 生命環境学部, 教授 (70722122)
• Project Period (FY): 2021-04-01 – 2024-03-31
• Keywords: 階層性進化 / 社会性昆虫 / ゲノミクス

Outline of Final Research Achievements

We conducted an empirical study using a social insect Pristomyrmex punctatus, which harbors intraspecific social parasites, in order to gain insight into the common principles in the evolution of biological hierarchies,. We obtained high-quality reference genomes of socially parasitic (cheater) and normal lineages, compared gene expression among lineages, and analyzed nestmate discrimination behavior as an integral part of colony hierarchy. The results suggest that the cheater lineage has co-opted queen traits from their ancestor species, and that when the cheaters invade other colonies, the hosting colony exhibits normal nest-mate discrimination behavior to exclude the invaders. These results will provide basic information for elucidating the evolutionary maintenance mechanisms of social systems and the molecular basis of caste differentiation in social insects.

Free Research Field

進化生態学

Academic Significance and Societal Importance of the Research Achievements

本研究が対象とした社会寄生現象の進化は，社会性昆虫の事例研究にとどまらず，生物の社会システムの起源・維持に関して，生物階層を問わない一般性を持ちうるものである．例えば，微生物集団のふるまいや，がん細胞の小進化プロセス，さらに人間社会の進化史的な成立においても，社会寄生者の問題は存在する．社会性昆虫の研究に絞っても，社会寄生系統は，野外で進化した「女王変異体」とみなすことが可能であるため，通常は表現型可塑性で生じる社会性昆虫の階級分化の分子メカニズムの理解に，新たなアプローチを与えることが期待される．