ABSTRACT: The importance of aquatic arthropods in the processing of organic matter in fluvial systems is well known, but this topic has been poorly studied in Neotropical rivers. In this research, we studied the composition of functional feeding groups (FFGs) associated with differences in elevation in a tropical river in northern Colombia during the wet and dry seasons. Between 2008 and 2013, we collected benthic arthropods at 3 sites located in the upper (San Lorenzo), intermediate (La Victoria) and lower (Puerto Mosquito) sections of the Gaira River. We found some differences in the gut contents and FFGs of the animals from different sites and between the climatic seasons. The dominant food source at all the sites and during both seasons was fine particulate organic matter (FPOM). At La Victoria, the genera Leptonema, Smicridea and Phylloicus (all belonging to Trichoptera) presented significant differences in the consumption of coarse particulate organic matter (CPOM) between the rainy and dry seasons (p < 0.05). At San Lorenzo, Leptonema had the highest animal tissue consumption value (p < 0.05). A discriminant function analysis based on gut contents suggested that some taxa may have been assigned to the wrong FFGs. We concluded that the diets of the aquatic arthropods in our study tended to present high trophic plasticity. Consequently, our results suggest that Neotropical rivers need to be re-evaluated in terms of traditionally established FFGs, which heretofore have been based on information from other regions of the world, producing incorrect assessments of aquatic systems.

中文翻译：

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为新热带山区河流中的水生节肢动物分配功能性摄食组

摘要：水生节肢动物在河流系统中有机物加工中的重要性是众所周知的，但是在新热带河流中，对该主题的研究很少。在这项研究中，我们研究了功能性饲料组（FFG）的组成，该饲料组与哥伦比亚北部热带河在干湿季节的海拔差异有关。在2008年至2013年之间，我们在盖拉河上游（圣洛伦佐），中游（拉维多利亚）和下游（波多黎各蚊帐）的3个地点采集了底栖节肢动物。我们发现不同地点以及气候季节之间动物的肠道含量和FFG有所不同。在所有地点和两个季节中，主要的食物来源都是细颗粒有机物（FPOM）。在维多利亚，Leptonema属，Smicridea和Phylloicus（均属于Trichoptera）在雨季和旱季之间的粗颗粒有机物（CPOM）消耗量上存在显着差异（p <0.05）。在Leptonema的San Lorenzo具有最高的动物组织消耗值（p <0.05）。基于肠道内容的判别功能分析表明，某些分类单元可能已分配给错误的FFG。我们得出的结论是，在我们的研究中，水生节肢动物的饮食往往表现出较高的营养可塑性。因此，我们的结果表明，新热带河流需要根据传统上建立的FFG进行重新评估，而FFG迄今为止是基于来自世界其他地区的信息，从而对水生系统产生了不正确的评估。