Aquatic–terrestrial linkages: Export of polyunsaturated fatty acids from aquatic ecosystems via emerging insects and potential consequences for terrestrial invertebrate consumers

有机质的跨生态系统通量对邻近生境的生产力具有重要影响。新兴的水生昆虫为淡水来源的有机物进入陆地食物网提供了重要途径。互惠资源补贴对相邻食物网过程的影响取决于补贴的数量；资源补贴的质量差异是否以及如何影响相邻的食物网过程尚未得到研究。该项目的目的是评估必需的和潜在的限制性生化营养素，即多不饱和脂肪酸（PUFA），通过新兴昆虫从淡水系统转移到陆地系统，并评估淡水来源的多不饱和脂肪酸对陆生无脊椎动物消费者的意义。将在不同的湖泊生态系统上安装涌现陷阱，以评估生境特定的多聚脂肪酸通量。使用稳定同位素标记基质的池塘实验将用于评估通过新兴昆虫出口的多硫化氢以及水生多硫化氢在邻近陆地生态系统和无脊椎动物消费者中的分布。实验室喂养实验将以河岸无脊椎捕食者（即蜘蛛）、水生和陆生昆虫猎物以及pufa处理的食物进行，以测试水生昆虫是否优先被食用，并比陆生昆虫猎物更有效地支持河岸捕食者的生长。这种方法将为必需营养素在调节跨生态系统效应中的潜在作用提供新的见解。

Cross-ecosystem fluxes of organic matter can crucially influence the productivity of adjacent habitats. Emerging aquatic insects provide an important pathway by which freshwater-derived organic matter can enter terrestrial food webs. Effects of reciprocal resource subsidies on adjacent food web processes depend on the quantity of the subsidy; if and how qualitative differences in resource subsidies can influence adjacent food web processes has not been studied yet. The objective of this project is to evaluate the transfer of essential and potentially limiting biochemical nutrients, i.e. polyunsaturated fatty acids (PUFA), from freshwater to terrestrial systems via emerging insects and to assess the significance of freshwater-derived PUFA for terrestrial invertebrate consumers. Emergence traps will be installed on different lake ecosystems to assess habitat-specific PUFA fluxes. Pond experiments with stable isotope-labelled substrates will be used to assess PUFA export via emerging insects and distribution of aquatic PUFA in adjacent terrestrial ecosystems and invertebrate consumers. Laboratory feeding experiments will be conducted with riparian invertebrate predators (i.e. spiders), aquatic and terrestrial insect prey and PUFA-manipulated food to test whether aquatic insects are preferentially consumed and support the growth of riparian predators more efficiently than terrestrial insect prey. This approach will provide novel insight into the potential role of essential nutrients in mediating cross-ecosystem effects.