Knowing the interactions between exotic and native species is essential to establish possible threats to the local fauna. In this study, we assessed the use of food resources and diet overlap between a recently introduced snail, Sinotaia quadrata, and a native species, Pomacea canaliculata. We analyzed the gut content and stable isotope of snails and resources in a lowland stream where both species coexist. Both Schoener’s and isotope dietary overlap indexes supported dietary overlap. Conversely, gut content analysis showed differences in consumption: S. quadrata consumed more detritus and diatoms than P. canaliculata, whose diet was characterized by detritus and macrophyte remains. Macrophytes were the resource that most contributed to the diet of both species, as shown by stable isotope mixing models. The combination of both techniques, gut content and stable isotope analysis, indicated that S. quadrata consumed macrophyte detritus while P. canaliculata ate fresh macrophytes. This difference indicates differential use of food resources between the studied species coexisting in a lowland stream. Although no negative trophic interaction was found, we highlight the importance of continuing to monitor interactions for other resources and studying possible risks to the local fauna.

了解外来物种和本地物种之间的相互作用对于确定对当地动物群的可能威胁至关重要。在这项研究中，我们评估了最近引入的蜗牛Sinotaia quadrata和本地物种Pomacea canaliculata之间食物资源的使用和饮食重叠。我们分析了蜗牛的肠道含量和稳定同位素以及两种物种共存的低地溪流中的资源。Schoener's 和同位素饮食重叠指数都支持饮食重叠。相反，肠道内容分析显示消耗量存在差异：S. quadrata比P. canaliculata消耗更多的碎屑和硅藻，其饮食以碎屑和大型植物残骸为特征。如稳定同位素混合模型所示，大型植物是对这两个物种的饮食贡献最大的资源。肠道含量和稳定同位素分析这两种技术的结合表明，S. quadrata消耗大型植物碎屑，而P. canaliculata食用新鲜的大型植物。这种差异表明共存于低地河流的研究物种之间对食物资源的不同利用。虽然没有发现负面的营养相互作用，但我们强调了继续监测其他资源相互作用和研究当地动物群可能面临的风险的重要性。