Abstract Generalist herbivores are less susceptible to changes in the plant composition of their habitats than specialists are because generalists can consume a diverse array of plants. However, even generalists exhibit dietary choices, for example because they need to balance their nutritional intake for both growth and reproduction. In this study, we showed that an endangered generalist herbivorous grasshopper (Celes akitanus; Orthoptera: Acrididae) actively chooses which plants to include in its diet. Moreover, we found that grasshopper abundance is correlated with host plant abundance and richness. This grasshopper has been reported to occur mainly in traditionally managed grasslands that harbour more diverse plant species than other, nearby grasslands. To elucidate the links between this grasshopper and plant richness, we surveyed grasshopper abundance in grasslands under traditional and other management practices. Plant DNA barcoding of faecal samples demonstrated that this grasshopper is a generalist herbivore while also showing that it makes active dietary choices. Furthermore, although the grasshopper's host plants occurred in all grasslands, the grasshopper itself was found only in species-rich grasslands. In addition, grasshopper abundance was positively related to the abundance and richness of host plants. Our findings suggest that this endangered herbivore requires a wide array of host plants to maintain its populations.

中文翻译：

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通才食草动物需要大量的植物物种来维持其种群

摘要 通才食草动物比专家更不易受其栖息地植物组成变化的影响，因为通才可以食用多种植物。然而，即使是通才也表现出饮食选择，例如，因为他们需要平衡生长和繁殖的营养摄入。在这项研究中，我们展示了一种濒临灭绝的多面食草蚱蜢（Celes akitanus；直翅目：蝗科）主动选择将哪些植物纳入其饮食。此外，我们发现蚱蜢丰度与寄主植物丰度和丰富度相关。据报道，这种蚱蜢主要发生在传统管理的草原上，这些草原比附近的其他草原拥有更多不同的植物物种。为了阐明这种蚱蜢与植物丰富度之间的联系，我们调查了传统和其他管理方式下草原上蚱蜢的数量。粪便样本的植物 DNA 条形码表明，这种蚱蜢是一种多才多艺的食草动物，同时也表明它做出积极的饮食选择。此外，虽然蚱蜢的寄主植物存在于所有草原，但蚱​​蜢本身仅在物种丰富的草原中被发现。此外，蝗虫丰度与寄主植物的丰度和丰富度呈正相关。我们的研究结果表明，这种濒临灭绝的食草动物需要大量寄主植物来维持其种群。此外，尽管蚱蜢的寄主植物存在于所有草原，但蚱​​蜢本身仅在物种丰富的草原中被发现。此外，蝗虫丰度与寄主植物的丰度和丰富度呈正相关。我们的研究结果表明，这种濒临灭绝的食草动物需要大量寄主植物来维持其种群。此外，虽然蚱蜢的寄主植物存在于所有草原，但蚱​​蜢本身仅在物种丰富的草原中被发现。此外，蝗虫丰度与寄主植物的丰度和丰富度呈正相关。我们的研究结果表明，这种濒临灭绝的食草动物需要大量寄主植物来维持其种群。