Insect herbivory on native and exotic aquatic plants: phosphorus and nitrogen drive insect growth and nutrient release

Eutrophication and globalisation facilitate the dominance of exotic plants in aquatic ecosystems worldwide. Aquatic omnivores can provide biotic resistance to plant invasions, but little is known about whether obligate aquatic herbivores can do the same. Herbivores such as insects can decimate aquatic vegetation, but may not be able to consume exotic plants due to their more or less specialised nature of feeding. We experimentally tested the larval feeding of an aquatic insect, the moth Parapoynx stratiotata, on eleven submerged plant species, from either native or exotic origin. We also tested whether insect herbivory stimulates nutrient and organic matter release, thus affecting water quality. Larvae of P. stratiotata consumed seven out of eleven plant species, and their growth was related to plant nutrient content and stoichiometry. However, larvae had no preference for either native or exotic macrophytes, and their plant preference was not related to the measured plant traits, but w...富营养化与全球化助推全球水生生态系统中外来植物占据优势地位。水生杂食动物可对植物入侵产生生物抵抗，但目前尚不清楚专性水生植食者是否也能发挥同等作用。诸如昆虫的植食动物可大量损毁水生植被，但由于其取食行为或多或少具有特化性，可能无法取食外来植物。本研究通过实验，针对分别源自本土与外来的11种沉水植物，测试了水生昆虫水螟蛾（Parapoynx stratiotata）的幼虫取食情况。本研究同时探究了昆虫植食作用是否会促进营养物质与有机质释放，进而影响水体水质。结果显示，水螟蛾（Parapoynx stratiotata）的幼虫可取食11种植物中的7种，其生长状况与植物的营养成分及化学计量特征相关。然而，该幼虫对本土或外来大型水生植物并无取食偏好，且其植物选择偏好与所测定的植物性状并无关联，但……