Department of Biology, Animal Ecology, Philipps-Universität Marburg, Marburg, Hesse, Germany.
Department of Biology, Conservation Ecology, Philipps-Universität Marburg, Marburg, Hesse, Germany.
PLoS One. 2023 Nov 7;18(11):e0288276. doi: 10.1371/journal.pone.0288276. eCollection 2023.
In tropical forests, herbivorous arthropods remove between 7% up to 48% of leaf area, which has forced plants to evolve defense strategies. These strategies influence the palatability of leaves. Palatability, which reflects a syndrome of leaf traits, in turn influences both the abundance and the mean body mass not only of particular arthropod taxa but also of the total communities. In this study, we tested two hypotheses: (H1) The abundance of two important chewer guilds ('leaf chewers' and 'rostrum chewers'), dominant components of arthropod communities, is positively related to the palatability of host trees. (H2) Lower palatability leads to an increased mean body mass of chewers (Jarman-Bell principle). Arthropods were collected by fogging the canopies of 90 tropical trees representing 31 species in three plots at 1000 m and three at 2000 m a.s.l. Palatability was assessed by measuring several 'leaf traits' of each host tree and by conducting a feeding trial with the generalist herbivore Gryllus assimilis (Orthoptera, Gryllidae). Leaf traits provided partial support for H1, as abundance of leaf chewers but not of rostrum chewers was positively affected by the experimentally estimated palatability. There was no support for H2 as neither leaf traits nor experimentally estimated palatability affected the mean body mass of leaf chewers. The mean body mass of rostrum chewers was positively related to palatability. Thus, leaf traits and experimentally estimated palatability influenced the abundance and mean body mass of chewing arthropods on the community level. However, the data were not consistent with the Jarman-Bell principle. Overall, our results suggest that the palatability of leaves is not among the dominant factors influencing abundance and mean body mass of the community of chewing arthropod herbivores. If other factors, such as the microclimate, predation or further (a-)biotic interactions are more important has to be analyzed in refined studies.
在热带森林中，食草节肢动物会去除 7%至 48%的叶片面积，这迫使植物进化出防御策略。这些策略影响叶片的适口性。适口性反映了叶片特征的综合表现，反过来又影响着特定节肢动物类群以及整个群落的丰度和平均体质量。在这项研究中，我们检验了两个假设：（H1）两个重要咀嚼类群（“叶片咀嚼者”和“喙咀嚼者”）的丰度，即节肢动物群落的主要成分，与宿主树的适口性呈正相关。（H2）较低的适口性会导致咀嚼者的平均体质量增加（贾尔曼-贝尔原理）。通过在 1000 米和 2000 米海拔的三个样地的树冠上喷雾收集 90 种热带树木的 31 个种的节肢动物，用通用草食性昆虫 Gryllus assimilis（直翅目，蟋蟀科）进行饲养试验来评估适口性。通过测量每个宿主树的几个“叶片特征”并进行饲养试验，叶片特征为 H1 提供了部分支持，因为叶片咀嚼者的丰度而不是喙咀嚼者的丰度受到实验估计适口性的正向影响。H2 没有得到支持，因为叶片特征和实验估计的适口性都没有影响叶片咀嚼者的平均体质量。喙咀嚼者的平均体质量与适口性呈正相关。因此，叶片特征和实验估计的适口性影响着咀嚼节肢动物群落的丰度和平均体质量。然而，数据与贾尔曼-贝尔原理不一致。总体而言，我们的研究结果表明，叶片的适口性并不是影响咀嚼节肢动物食草动物群落丰度和平均体质量的主要因素之一。如果其他因素，如微气候、捕食或进一步的（非）生物相互作用更重要，那么需要在更精细的研究中进行分析。
