Galled leaves are very frequent in southern beech (Nothofagus pumilio) forests. We compared the consumption of leaves (galled and ungalled) by two detritivores and the effect of this consumption on detritivore nutrient content. The amphipod Hyalella curvispina and larvae of the caddisfly Monocosmoecus hyadesi were fed with two diet treatments for 30 days: (1) ungalled leaves and (2) galled leaves. Fungal biomass, carbon (C), nitrogen (N), and phosphorus (P) content were measured in leaves and detritivores, and C:N:P molar ratios were calculated. We hypothesized that galls produce changes in litter nutrient content, affecting invertebrate consumption and nutrient content. Galled leaves had higher N and ergosterol content, and lower C:N ratios than ungalled leaves. Galled leaf consumption was higher than the ungalled for both detritivores. The two species differed in the content of N and C (caddisfly > amphipod) and P (caddisfly < amphipod). The N:P ratio of the amphipods was similar to the ungalled leaf ratio and increased when fed on galled leaves. In contrast, the N:P ratio of the caddisflies was considerably higher than the ungalled leaves and decreased when fed on galled leaves. Galls alter nutrient content in leaves and increase fungal biomass. Both detritivore species were highly homeostatic with regard to C:N ratio, but caddisflies could overcome the limited P content by increasing consumption. We highlight the impact of galls on aquatic detritivores, which in turn are relevant in forested streams for recycling organic matter and cascading effects through brown detritus-based aquatic food webs.

在南部山毛榉 ( Nothofagus pumilio ) 森林中，枯萎的叶子非常常见。我们比较了两种碎屑动物对叶子（磨损和未磨损）的消耗以及这种消耗对碎屑动物营养成分的影响。该端足Hyalella curvispina和幼虫石蛾的Monocosmoecus hyadesi用两种饮食处理喂养 30 天：(1) 未剥落的叶子和 (2) 剥落的叶子。真菌生物量、碳 (C)、氮 (N) 和磷 (P) 含量在叶子和食腐动物中进行了测量，并计算了 C:N:P 摩尔比。我们假设虫瘿会导致垫料营养成分发生变化，从而影响无脊椎动物的消耗和营养成分。没毛的叶子比没毛的叶子具有更高的 N 和麦角甾醇含量，以及更低的 C:N 比。对于这两种食腐动物来说，去核的叶子消耗量高于未去核的。这两个物种的N和C含量不同（caddisfly > amphipod）和P（caddisfly < amphipod）。片脚类动物的 N:P 比率与未磨损叶片的比率相似，并且在以磨损叶片为食时会增加。相比之下，N：石蛾的磷比显着高于未磨损的叶子，并且在以磨损的叶子为食时会降低。胆汁会改变叶子中的营养成分并增加真菌生物量。两种食腐动物在 C:N 比方面都具有高度稳态，但石蛾可以通过增加消耗来克服有限的 P 含量。我们强调了虫瘿对水生碎屑动物的影响，而这反过来又与森林溪流中的有机物质循环利用和通过基于棕色碎屑的水生食物网产生的级联效应相关。