Kralj-Fišer Simona, Premate Ester, Copilaş-Ciocianu Denis, Volk Teja, Fišer Žiga, Balázs Gergely, Herczeg Gábor, Delić Teo, Fišer Cene
Scientific and Research Centre of the Slovenian Academy of Sciences and Arts, Institute of Biology, Novi trg 2, SI-1000 Ljubljana, Slovenia.
Department of Biology, Biotechnical Faculty, University of Ljubljana, Jamnikarjeva 101, SI-1000 Ljubljana, Slovenia.
Zoology (Jena). 2020 Apr;139:125742. doi: 10.1016/j.zool.2020.125742. Epub 2020 Jan 13.
Locomotion is an important, fitness-related functional trait. Environment selects for type of locomotion and shapes the morphology of locomotion-related traits such as body size and appendages. In subterranean aquatic arthropods, these traits are subjected to multiple, at times opposing selection pressures. Darkness selects for enhanced mechano- and chemosensory systems and hence elongation of appendages. Conversely, water currents have been shown to favor short appendages. However, no study has addressed the variation in locomotion of invertebrates inhabiting cave streams and cave lakes, or questioned the relationship between species' morphology and locomotion. To fill this knowledge gap, we studied the interplay between habitat use, morphology and locomotion in amphipods of the subterranean genus Niphargus. Previous studies showed that lake and stream species differ in morphology. Namely, lake species are large, stout and long-legged, whereas stream species are small, slender and short-legged. We here compared locomotion mode and speed between three lake and five stream species. In addition, we tested whether morphology predicts locomotion. We found that the stream species lie on their body sides and move using slow crawling or tail-flipping. The species inhabiting lakes move comparably faster, and use a variety of locomotion modes. Noteworthy, one of the lake species almost exclusively moves in an upright or semi-upright position that resembles walking. Body size and relative length of appendages predict locomotion mode and speed in all species. We propose that integrating locomotion in the studies of subterranean species might improve our understanding of their morphological evolution.
运动能力是一项与健康相关的重要功能特征。环境会选择特定的运动类型，并塑造与运动相关特征的形态，如体型和附肢。在地下水生节肢动物中，这些特征会受到多种有时甚至相互对立的选择压力影响。黑暗环境会促使机械和化学感觉系统增强，从而导致附肢伸长。相反，水流已被证明有利于短附肢的形成。然而，尚无研究探讨栖息在洞穴溪流和洞穴湖泊中的无脊椎动物的运动差异，也没有人质疑物种形态与运动之间的关系。为了填补这一知识空白，我们研究了地下尼氏钩虾属（Niphargus）的栖息地利用、形态与运动之间的相互作用。此前的研究表明，湖泊物种和溪流物种在形态上存在差异。具体而言，湖泊物种体型大、粗壮且腿长，而溪流物种体型小、细长且腿短。我们在此比较了三种湖泊物种和五种溪流物种的运动模式和速度。此外，我们还测试了形态是否能预测运动情况。我们发现，溪流物种侧身躺着，通过缓慢爬行或尾部摆动来移动。栖息在湖泊中的物种移动速度相对较快，且使用多种运动模式。值得注意的是，其中一种湖泊物种几乎完全以直立或半直立的姿势移动，类似于行走。体型和附肢的相对长度能够预测所有物种的运动模式和速度。我们认为，将运动能力纳入对地下物种的研究中，可能会增进我们对其形态进化的理解。
