Exotic plants are common in urban landscapes and are often planted by landscape managers in an effort to reduce herbivory damage and improve landscape aesthetics. However, exotic plants may be less palatable to many native insects and reduce herbivore biomass that may fuel higher trophic levels. Furthermore, a loss of herbivores in exotic ornamental landscapes may reduce top-down control by natural enemies. In this study, we compare herbivory in native and exotic congener ornamental landscapes. We also explore if caterpillar abundance, natural enemy abundance, diversity, community composition, spider biomass, and egg predation differ between the two landscape types. We predicted that herbivory, as well as natural enemy abundance and predation would be greater in native landscapes. Although we found that leaf area lost to herbivory was greater in native plots in one of the collection years, this relationship was weak. Natural enemy diversity differed between landscape types, but depended on plant genus. The relationship between plant origin and natural enemy diversity was also weak. Caterpillar abundance, natural enemy community composition, spider biomass, and predation services did not differ between treatments. Overall, our results suggest that ornamental landscapes planted in native plants may not differ from landscapes planted in exotic congeners in the pest management and conservation services they provide, particularly with regard to invertebrate natural enemies. However, our findings cannot be used to make more general claims about plant origin, especially with regard to native plants and non-congeners, as we only compared ornamental landscapes with native plants and their exotic congeners in this study. We conclude that for optimizing natural enemy diversity and biomass on city landscapes, plant choice and other plant traits may be as important as plant origin to consider. Our work demonstrates that both native and exotic congener ornamental landscapes provide valuable ecosystem services and will help guide landscape design that serves both the people and wildlife that use them.

中文翻译：

---

本地和外来同源物对无脊椎动物天敌多样性，可用蜘蛛生物量和居住区景观害虫防治服务的影响

外来植物在城市景观中很常见，并且通常由景观管理者种植，以减少草食动物的损害并改善景观美感。但是，外来植物对许多本地昆虫的口感可能较差，并减少了草食动物的生物量，而后者可能会增加较高的营养水平。此外，在异国情调的观赏性景观中食草动物的流失可能会减少天敌的自上而下的控制。在这项研究中，我们比较了本土和外来同类装饰景观中的食草动物。我们还探讨了两种景观类型之间毛虫的丰富度，天敌的丰富度，多样性，群落组成，蜘蛛生物量和卵捕食性是否不同。我们预测，在自然景观中，草食动物以及天敌的丰富度和掠夺性将会更大。尽管我们发现，在采集的某一年中，在原生地上因草食而损失的叶面积更大，但这种关系很弱。天敌的多样性在景观类型之间有所不同，但取决于植物属。植物起源与天敌多样性之间的关系也很弱。不同处理之间的毛毛虫丰度，天敌群落组成，蜘蛛生物量和捕食服务没有差异。总体而言，我们的结果表明，本地植物种植的观赏性景观与异国同类种植的景观在提供害虫管理和保护服务方面（尤其是无脊椎动物天敌）可能没有区别。但是，我们的发现不能用于对植物起源，尤其是对天然植物和非同类植物，做出更一般的主张，因为我们在本研究中仅将观赏性景观与本土植物及其异国同类植物进行了比较。我们得出结论，为优化城市景观上自然天敌的多样性和生物量，植物选择和其他植物性状可能与植物起源一样重要。我们的工作表明，本土和外来的同类观赏景观都提供了宝贵的生态系统服务，并将有助于指导景观设计，从而为使用这些景观的人和野生动物服务。