Silkstone B E
Department of Biology, The University, Building 44, SO9 5NH, Southampton, UK.
Oecologia. 1987 Nov;74(1):149-152. doi: 10.1007/BF00377360.
Low levels of artificial damage were imposed on the leaves of Betla pubescens and B. pendula in early summer 1985. Sixteen tress were used and the damage was distributed throughout the canopy in two ways. It was either randomly dispersed on the tree, or restricted to a localised region of the canopy. Up to 250 leaves/tree were damaged and the position of control leaves was marked as appropriate. At the end of the summer the experimental and control leaves were collected for analysis. Subsequent patterns of grazing by naturally-occurring herbivores were affected by the previous damage to the foliage. Fewer artificially-damaged leaves received subsequent insect grazing damage. The frequecy distribution of insect damage to previously-damaged leaves was significantly different from that of the control leaves, and less leaf tissue was removed from those experimental leaves which did receive subsequent insect attack. The evidence presented suggests that wound-induced changes in leaf palatability do occur in B. pubescens and B. pendula in the field and that a major role is to disperse the damage throughout the canopy.
1985年夏初，对欧洲白桦和垂枝桦的叶片施加了低水平的人为损伤。使用了16棵树，损伤以两种方式分布在整个树冠上。要么随机分散在树上，要么局限于树冠的局部区域。每棵树多达250片叶子受到损伤，并适当地标记了对照叶子的位置。夏末，收集实验叶和对照叶进行分析。先前叶片受到的损伤影响了自然食草动物随后的啃食模式。较少有人为损伤的叶子受到后续昆虫啃食的损害。先前受损叶片的昆虫损伤频率分布与对照叶片显著不同，并且在那些确实受到后续昆虫攻击的实验叶片上，较少的叶组织被啃食。所提供的证据表明，伤口诱导的叶片适口性变化在野外的欧洲白桦和垂枝桦中确实会发生，并且一个主要作用是将损伤分散到整个树冠。
