Ecological study on the adaptive significance of autumn leaf colouration

在四个地点的三种树种中，对两种解释秋叶颜色适应性意义的假说（共同进化假说：颜色是树木防御食草动物的真实警告信号，三营养相互作用假说：颜色在秋季吸引嗜蜜蚜虫，在第二年春天蚂蚁参与蚜虫保护树木免受食草动物的侵害）进行了实地测试。这两种假设都没有得到支持。然而，在两种树种中，秋叶颜色与对草食性昆虫的抗性之间存在显著的相关性。通过对150多种植物春季新叶和秋季旧叶颜色的比较，发现许多植物新叶的颜色与秋季旧叶的颜色不同，表明春秋两季不同的自然选择作用于叶片颜色。

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.