Social interaction driven developmental reaction norm

2019 Fiscal Year Final Research Report

• Project/Area Number: 17H03726
• Research Category: Grant-in-Aid for Scientific Research (B)
• Allocation Type: Single-year Grants
• Section: 一般
• Research Field: Ecology/Environment
• Research Institution: Hokkaido University
• Principal Investigator: Nishimura Kinya 北海道大学, 水産科学研究院, 准教授 (30222186)
• Project Period (FY): 2017-04-01 – 2020-03-31
• Keywords: Reaction norm / Developmental trajectory / Cannibalism dimorphism / エゾサンショウウオ

Outline of Final Research Achievements

Cannibalism is induced in larval-stage populations of the Hokkaido salamander, Hynobius retardatus, under the control of a cannibalism reaction norm. Here, I examined phenotypic expression under the cannibalism reaction norm, and how the induction of a cannibalistic morph under the norm leads to populational morphological diversification. Morphology of cannibal and noncannibal individuals were found to be located at either end of a continuum of expression following a unique morphological integration rule that was different from the rule governing the size and shape variations of the solitary morph type. This result implies that the high-density-driven inducible morphology of an individual is governed by a common integration rule during the development of dimorphism under the control of the cannibalism reaction norm. The induced cannibalistic morph thus reflects not only by contest-type exploitative competition but also interference competition.

Free Research Field

進化行動生態学

Academic Significance and Societal Importance of the Research Achievements

エゾサンショウウオの共食いは、両生類の幼生期間の一時期に、表現型可塑性によって生じる著しい形態変化を伴う現象だ。進化行動生態学者は、共食いの機能、共食い形態の機能、共食い形態にならない個体の適応性、形態、その機能などについて興味を抱く。進化発生学者は、それらに形態の発現パターンや発現メカニズムに興味を抱く。自然観察や生物採集に夢中な小学生や中学生が、身近な池にいるこの両生類の見せるダイナミックな生活史の様相にワクワクする。本研究は、こうした生物科学研究分野や自然教育分野に、共食い現象についての科学的理解とさらなる探求への刺激を提供する。