competition using information among males in fish

2022 Fiscal Year Final Research Report

• Project/Area Number: 18K06427
• 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: Osaka Metropolitan University (2022); Osaka City University (2018-2021)
• Principal Investigator: Ota Kazutaka 大阪公立大学, 大学院理学研究科, 客員研究員 (50527900)
• Project Period (FY): 2018-04-01 – 2023-03-31
• Keywords: 代替繁殖戦術 / なわばり雄 / スニーカー / 意思決定

Outline of Final Research Achievements

I investigated the reproductive strategies of sneakers and territorial males of the small marine fish, triplefin blenny (Enneapterygius etheostoma). Sneakers intensively observed the behaviour of territorial males and approached the spawning pair using pause-travel locomotion, to start the sneaking rush towards them at a closer position. They repeatedly try sneaking at a spawning site, and movements during a series of sneaking attempts were explained by Brownian locomotion. I also observed that sneakers consecutively used the same locations after succeeding in sneaking (i.e. learning) and changed the location after failing the attempts, which indicates a trial-and-error search pattern. Territorial males did not spend much time scanning the surroundings but attacked when they detected the sneaker's movements, suggesting that they took passive strategies against sneakers. Altogether, how both sneakers and territorial males move to succeed in fertilization influenced each other.

Free Research Field

生態学

Academic Significance and Societal Importance of the Research Achievements

代替繁殖戦術はダーウィンの時代から知られる現象で、多くの分類群で観察される普遍的な生命現象です。本研究は、スニーカーが繁殖（スニーキング）に用いる行動や意思決定が捕食者や被食者に似るということを見出しました。これは、捕食・被食行動が代替繁殖戦術の進化の前適応になっているという可能性を指摘するものです。なぜ代替繁殖戦術が幅広い分類群で見つかるのか？という問いの一つの答えがこの前適応にあるのかもしれません。このような指摘はこれまで皆無であり、学術的に意義のある成果を得たと考えます。