Analyses of Kenyon cell type diversification in hymenopteran insect brains and its relationship with behavioral evolution

2022 Fiscal Year Final Research Report

• Project/Area Number: 20H03300
• 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: Takeo Kubo 東京大学, 大学院理学系研究科(理学部), 教授 (10201469)
• Project Period (FY): 2020-04-01 – 2023-03-31
• Keywords: ミツバチ / ハバチ / ハチ目昆虫 / キノコ体 / ケニヨン細胞 / エクダイソン情報伝達系 / 進化動態 / ゲノム編集

Outline of Final Research Achievements

We have previously reported that the number of Kenyon cell subtypes that constitute the mushroom bodies, a higher brain center of the honey bees, increased from 1 type in solitary/phytophagous sawflies that have ancestral traits, to 2 types in solitary/parasitic Apocrita species, and to 3 types in nidificating/social Aculeate species, in correlation with the behavioral evolution in hymenopteran insects, suggesting that the increase in the number of Kenyon cell subtypes may have served as a neural basis for behavioral evolution in hymenopteran insects. In this research project, we elucidated for the first time the evolutionary dynamics of the Kenyon cell subtypes that constitute the mushroom bodies of hymenopteran insects and proposed the possibility that transcription factors that function in the ecdysone signaling pathway are remobilized to have unique target genes as the molecular basis for the generation of new Kenyon cell subtypes.

Free Research Field

生物科学

Academic Significance and Societal Importance of the Research Achievements

ハチ目昆虫ではミツバチなどの営巣性/社会性の種類（有剣類）が良く知られているが、単独性（ハバチなど）や寄生性の種類（有錐類）も存在し、多様な行動様式を示す種類を含む分類群である。加えて、ハチ目昆虫は哺乳類に比べ小さく簡単な構造の脳をもつため、行動進化の基盤となった神経機構の進化を調べる上で有用である。ヒトを含む高等動物の脳では高次脳機能は大脳新皮質の各領野に分配されているが、こうした脳機能局在の生理的意義とその進化の分子神経基盤はほとんど不明である。本研究で得られた知見は、ハチ目のみならず動物一般の高次脳機能の進化の理解にも寄与し得る、学術的に重要な研究成果と考えられる。