Are tree species diversity and genotypic diversity effects on insect herbivores mediated by ants?

Plant diversity can influence predators and omnivores and such effects may in turn influence herbivores and plants. However, evidence for these ecological feedbacks is rare. We evaluated if the effects of tree species (SD) and genotypic diversity (GD) on the abundance of different guilds of insect herbivores associated with big-leaf mahogany (Swietenia macrophylla) were contingent upon the protective effects of ants tending extra-floral nectaries of this species. This study was conducted within a larger experiment consisting of mahogany monocultures and species polycultures of four species and –within each of these two plot types– mahogany was represented by either one or four maternal families. We selected 24 plots spanning these treatment combinations, 10 mahogany plants/plot, and within each plot experimentally reduced ant abundance on half of the selected plants, and surveyed ant and herbivore abundance. There were positive effects of SD on generalist leaf-chewers and sap-feeders, b...植物多样性可对捕食者与杂食动物产生影响，而此类效应反过来又可作用于草食动物与植物。然而，针对这类生态反馈的相关证据仍较为匮乏。我们评估了树种多样性（SD）与基因型多样性（GD）对关联于大果桃花心木（Swietenia macrophylla）的不同昆虫草食动物功能群丰度的影响，是否取决于该物种外生花蜜腺（extra-floral nectaries）所吸引蚂蚁的保护作用。 本研究依托一项更大规模的实验开展，该实验包含桃花心木纯林以及由4个物种组成的多物种种混交林；且在这两种样地类型中，桃花心木均分别由1个或4个母本家系构成。我们共遴选了24个覆盖上述处理组合的样地，每个样地种植10株桃花心木；在每个样地内，我们对半数选定植株的蚂蚁丰度进行了人工去除处理，并对蚂蚁与草食动物的丰度开展了调查。树种多样性对广食性叶食性昆虫以及树液取食类昆虫存在正向效应，b...