Institute of Zoology, University of Innsbruck, Innsbruck, Austria.
Faculty of Natural Sciences, Matej Bel University, Banská Bystrica, Slovakia.
PLoS One. 2024 Feb 15;19(2):e0298367. doi: 10.1371/journal.pone.0298367. eCollection 2024.
Diamesa species (Diptera, Chironomidae) are widely distributed in freshwater ecosystems, and their life cycles are closely linked to environmental variables such as temperature, water quality, and sediment composition. Their sensitivity to environmental changes, particularly in response to pollution and habitat alterations, makes them valuable indicators of ecosystem health. The challenges associated with the morphological identification of larvae invoke the use of DNA barcoding for species determination. The mitochondrial cytochrome oxidase subunit I (COI) gene is regularly used for species identification but faces limitations, such as similar sequences in closely related species. To overcome this, we explored the use of the internal transcribed spacers (ITS) region in addition to COI for Diamesa larvae identification. Therefore, this study employs a combination of molecular markers alongside traditional morphological identification to enhance species discrimination. In total, 129 specimens were analysed, of which 101 were sampled from a glacier-fed stream in Rotmoostal, and the remaining 28 from spring-fed streams in the neighbouring valleys of Königstal and Timmelstal. This study reveals the inadequacy of utilizing single COI or ITS genes for comprehensive species differentiation within the genus Diamesa. However, the combined application of COI and ITS markers significantly enhances species identification resolution, surpassing the limitations faced by traditional taxonomists. Notably, this is evident in cases involving morphologically indistinguishable species, such as Diamesa latitarsis and Diamesa modesta. It highlights the potential of employing a multi-marker approach for more accurate and reliable Diamesa species identification. This method can be a powerful tool for identifying Diamesa species, shedding light on their remarkable adaptations to extreme environments and the impacts of environmental changes on their populations.
狄梅萨种（双翅目，摇蚊科）广泛分布于淡水生态系统中，其生命周期与环境变量密切相关，如温度、水质和沉积物组成。它们对环境变化的敏感性，特别是对污染和栖息地改变的反应，使它们成为生态系统健康的有价值的指标。幼虫形态鉴定的挑战促使人们使用 DNA 条形码来确定物种。线粒体细胞色素氧化酶亚基 I（COI）基因通常用于物种鉴定，但面临着与近缘物种序列相似的限制。为了克服这一问题，我们探讨了在 COI 之外使用内部转录间隔区（ITS）区域来鉴定狄梅萨幼虫。因此，本研究采用分子标记与传统形态鉴定相结合的方法来增强物种区分。总共分析了 129 个标本，其中 101 个是从罗特莫斯特冰川溪流中采集的，其余 28 个是从科尼格塔尔和蒂姆梅尔斯塔尔相邻山谷的泉水溪流中采集的。本研究表明，单独使用 COI 或 ITS 基因不足以全面区分狄梅萨属内的物种。然而，COI 和 ITS 标记的联合应用显著提高了物种鉴定的分辨率，克服了传统分类学家所面临的限制。值得注意的是，这种情况在形态上无法区分的物种中尤为明显，如狄梅萨宽跗摇蚊和狄梅萨中突摇蚊。这突显了采用多标记方法进行更准确和可靠的狄梅萨物种鉴定的潜力。这种方法可以成为鉴定狄梅萨物种的有力工具，揭示了它们对极端环境的惊人适应能力，以及环境变化对其种群的影响。
