The life-history traits of amphibitic insects are not well understood. These insects inhabit saturated interstitial areas below the riverbed (hyporheic zone) at the larval stage, mate in terrestrial habitats, and return to rivers for oviposition, but there is no knowledge concerning their dispersal characteristics. We sought to address this by examining how far amphibitic insects disperse away from the channel (laterally) and along upstream or downstream (longitudinally) in a gravel-bed river. Alloperla ishikariana was selected as the focal species because it numerically dominates other amphibites in an 18-km study segment of a 4th-order gravel-bed river in Hokkaido, Northern Japan. Malaise traps were set at various distances from the channel towards the riparian forest to estimate lateral dispersal distances. An elevated stable nitrogen isotope ratio in downstream larvae, caused by the influence of effluent from a wastewater treatment plant, was used to assess longitudinal dispersal by identifying and tracking adult movements. Laterally, 50th and 90th percentile dispersal distances were 11.66 and 35.09 m for female A. ishikariana and 20.59 and 59.20 m for male, respectively; this overlapped with distances previously estimated for other aquatic benthic taxa. Longitudinally, 50th and 90th percentile dispersal distances were 0.74 and 1.43 km for female and 3.11 and 7.87 km for male, respectively. Alloperla ishikariana had one of the longest upstream traveling distances compared with other aquatic insects, and the longest among Plecoptera taxa known thus far where male exhibited a greater dispersal distance. A higher number of adults demonstrated upstream movement, suggesting an upstream bias in the longitudinal dispersal of A. ishikariana. Overall, amphibitic stoneflies did not exhibit distinct dispersal characteristics compared with the results of previous reports on presumably benthic taxa. Our findings support an improved visualization of a multi-dimensionally connected river ecosystem in terms of material flow, including vertical connectivity.

两栖昆虫的生活史特征尚不清楚。这些昆虫在幼虫阶段栖息于河床以下的饱和间隙（hyporheic zone），在陆地栖息地交配，并返回河流产卵，但对其传播特征尚不清楚。我们试图通过检查两栖昆虫在砾石床河流中从通道（横向）和上游或下游（纵向）分散的距离来解决这个问题。比目鱼被选为焦点物种是因为它在日本北部北海道 4 级砾石床河的 18 公里研究段中在数量上占其他两栖动物的主导地位。萎靡不振陷阱设置在从通道到河岸森林的不同距离处，以估计横向扩散距离。由于污水处理厂流出物的影响，下游幼虫的稳定氮同位素比率升高，用于通过识别和跟踪成虫运动来评估纵向扩散。横向上，雌性A. ishikariana 的50% 和 90% 分散距离分别为 11.66 和 35.09 m男性分别为 20.59 和 59.20 m；这与先前估计的其他水生底栖类群的距离重叠。纵向上，女性的 50% 和 90% 分散距离分别为 0.74 和 1.43 公里，男性分别为 3.11 和 7.87 公里。与其他水生昆虫相比，Alloperla ishikariana是上游移动距离最长的昆虫之一，也是迄今为止已知的 Plecoptera 类群中最长的，雄性的传播距离更大。更多数量的成虫表现出向上游移动，表明A. ishikariana的纵向扩散存在上游偏差. 总体而言，与先前关于可能是底栖类群的报告的结果相比，两栖石蝇没有表现出明显的扩散特征。我们的研究结果支持在物质流（包括垂直连通性）方面对多维连接的河流生态系统进行改进的可视化。