Molecular mechanisms underlying semi-lunar reproductive rhythms in sesarmid crabs

2023 Fiscal Year Final Research Report

• Project/Area Number: 21K15163
• Research Category: Grant-in-Aid for Early-Career Scientists
• Allocation Type: Multi-year Fund
• Review Section: Basic Section 45040:Ecology and environment-related
• Research Institution: Kanazawa University (2022-2023); Niigata University (2021)
• Principal Investigator: Toyota Kenji 金沢大学, 環日本海域環境研究センター, 特任助教 (00757370)
• Project Period (FY): 2021-04-01 – 2024-03-31
• Keywords: アカテガニ / 月周期繁殖リズム / 眼柄

Outline of Final Research Achievements

To investigate the reproductive rhythms of the Japanese Sea population of the sesarmid crab and determine the presence of such rhythms in males, field survey on Sado Island were conducted. The results revealed that, like their Pacific counterparts, the Sado Island population exhibits lunar-related rhythms, with clear sex-specific differences. In pursuit of understanding the mechanisms underlying the lunar-dependent reproductive rhythms of this species, candidate factors were selected through RP-HPLC and RNAseq targeting the eyestalk. The studies identified peptides specific to new and full moons using RP-HPLC, while RNAseq revealed a group of endocrine pathway genes that peak during new and full moons, showing a biweekly expression pattern.

Free Research Field

生理生態学

Academic Significance and Societal Importance of the Research Achievements

これまでアカテガニに見られる月周繁殖リズムは潮汐差の乏しい日本海側個体群では観察されないと考えられてきた。しかし、本研究によって、佐渡島個体群では満月と新月にピークを有する明確な月周繁殖リズムを示すこと、さらにそのリズムには明確な雌雄差があることを初めて示した。本研究成果は、従来の定説を覆すものであると同時に、アカテガニの繁殖に関わる行動リズムに明瞭な雌雄差があることを世界で初めて示した。