2012 Fiscal Year Final Research Report

Ecological study on the adaptive significance of autumn leaf colouration

Research Project

Project/Area Number	22580177
Research Category	Grant-in-Aid for Scientific Research (C)
Allocation Type	Single-year Grants
Section	一般
Research Field	Forest science
Research Institution	Osaka City Institute of Public Health and Environmental Sciences
Principal Investigator	YAMAZAKI Kazuo 大阪市立環境科学研究所, その他部局等, 研究員 (30332448)
Project Period (FY)	2010 – 2012
Keywords	紅葉 / 共進化 / アブラムシ / アリ / 適応的意義
Research Abstract	Two hypotheses explaining the adaptive significance of autumn leaf colors (coevolution hypothesis: the color is an honest warning signal of tree defence against herbivores, tritrophic interaction hypothesis: the color attracts myrmecophilous aphids in autumn and in next spring ants attending the aphids defend trees from herbivores) were tested in the field using three tree species of four sites. Neither hypotheses were supported. However, in two tree species, there was significant correlation between autumn leaf colors and resistance against herbivorous insects. The comparison of colors of new spring leaves with those of old autumn leaves in more than 150 plant species revealed that in many species the colors of new leaves were different from those of old leaves, suggesting different natural selection acting on leaf colors between in spring and in autumn.