Reproductive system of deep-sea cephalopods

2023 Fiscal Year Final Research Report

• Project/Area Number: 21K06333
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Review Section: Basic Section 45040:Ecology and environment-related
• Research Institution: Shimane University
• Principal Investigator: Hiroashi Noritaka 島根大学, 学術研究院農生命科学系, 教授 (90376997)
• Project Period (FY): 2021-04-01 – 2024-03-31
• Keywords: 深海生物 / 繁殖様式 / 乱婚 / 父性解析

Outline of Final Research Achievements

ed the reproductive patterns of the firefly squid, Anguilla japonica, a close relative of the firefly squid, Anguilla japonica. The firefly squid, in Toyama Bay has a breeding season from early summer to autumn, and the proportion of males increased from October onward. Microsatellite markers were developed to examine the paternity of sperm masses attached to females, which were found to be promiscuous. Furthermore, in the latter half of the breeding season, the sex ratio was skewed toward males, and there was a corresponding diversification in sperm delivery sites.
We found that females of the brown squids have three sperm delivery sites, and that there is a rule of thumb regarding the use of these three sites, with the buccal membrane always being used for the first time during copulation, and finally the area behind the eyes. In addition, a small number of males were observed to use all three sites.

Free Research Field

海洋生物学

Academic Significance and Societal Importance of the Research Achievements

海洋生物の多くは繁殖行動が不明である。特に深海生物のそれは観察が極めて困難なためほとんど知見がなかった。本研究を通して、ホタルイカ、ホタルイカモドキ、そしてダイオウイカの繁殖に関する新知見を得ることができたことは、今後自然や地球環境や生物多様性を一般人に理解してもらう時に役立つと期待される。特に水族館のような科学リテラシー、アウトリーチに特化した施設における最新知見の提供は。社会的貢献度の高いものとなっている。