Abiotic factors can affect plant performance and cause stress, which in turn affects plant-herbivore interactions. The Environmental Stress Hypothesis (ESH) predicts that gall-inducing insect diversity will be greater on host plants that grow in stressful habitats. We tested this hypothesis, considering both historical and ecological scales, using the plant Copaifera langsdorffii Desf. (Fabaceae) as a model because it has a wide geographic distribution and is a super-host of gall-inducing insects. According to the ESH, we predicted that 1) on a historical scale, the diversity of gall-inducing insects will be higher in habitats with greater environmental stress and 2) on an ecological scale, gall-inducing insect diversity will be greater on plants that possess greater levels of foliar sclerophylly. We sampled gall-inducing insects on plants of C. langsdorffii in five sites with different levels of water and soil nutrient availability and separated from each other by a distance of up to 470 km. The composition, richness, and abundance of gall-inducing insects varied among study sites. Plants located in more stressful habitats had higher levels of foliar sclerophylly; but richness and abundance of gall-inducing insects were not affected by host plant sclerophylly. Habitat stress was a good predictor of gall-inducing insect diversity on a regional scale, thus corroborating the first prediction of the ESH. No relationship was found between plant sclerophylly and gall-inducing insect diversity within habitats. Therefore, on a local scale, we did not find support for our second prediction related to the ESH.

中文翻译：

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与广泛分布的热带树种相关的胆汁诱导昆虫的多样性：测试环境压力假设

非生物因素会影响植物性能并引起压力，进而影响植物与食草动物的相互作用。环境压力假说 (ESH) 预测，在压力生境中生长的寄主植物上，引起虫瘿的昆虫多样性会更高。我们使用植物 Copaifera langsdorffii Desf 测试了这一假设，同时考虑了历史和生态规模。（豆科）作为一个模型，因为它具有广泛的地理分布并且是诱导瘿的昆虫的超级宿主。根据 ESH，我们预测 1) 在历史尺度上，环境压力较大的栖息地中引起瘿的昆虫的多样性将更高；2) 在生态尺度上，引起瘿的昆虫多样性将在具有较大环境压力的植物上更高具有更高水平的叶硬化。我们在 C. langsdorffii 分布在水和土壤养分利用率不同的五个地点，并且彼此相隔长达 470 公里。诱导瘿的昆虫的组成、丰富度和丰度因研究地点而异。位于压力更大的栖息地的植物具有更高水平的叶硬质；但引起瘿的昆虫的丰富度和丰度不受寄主植物硬叶病的影响。栖息地压力是区域尺度上诱导虫瘿的昆虫多样性的良好预测因子，从而证实了 ESH 的首次预测。没有发现植物硬叶病与栖息地内诱导虫瘿的昆虫多样性之间存在关系。因此，在局部范围内，我们没有找到与 ESH 相关的第二个预测的支持。