Hydraulic niche descriptors of final instar larvae of nine Drusus species (Trichoptera) were studied in small, spring-fed, first-order headwaters located in the Mühlviertel (Upper Austria), Koralpe (Carinthia, Austria), and in the Austrian and Italian Alps. The species investigated covered all three clades of Drusinae: the shredder clade (Drusus franzi, D. alpinus), the grazer clade (D. biguttatus, D. chauvinianus, D. dudor, D. monticola), and the filtering carnivore clade (D. chrysotus, D. katagelastos, D. muelleri). Flow velocity was measured at front center of 68 larvae, head upstream, on the top of mineral substrate particles at water depths of 10–30 mm, using a tripod-stabilized Micro propeller meter (propeller diameter = 10 mm). Each data series consisted of a sampled measurement lasting 30 s (measuring interval = 1 s). In total, 2040 single velocity measurements were taken. Instantaneous flow velocities and drag at the sites of the 68 larvae varied from 0 to 0.93 m s⁻¹ and 0 to 8346 *10⁻⁶ N, respectively. Flow velocities and drag between the three clades were highly significantly different (p < 0.001); mean velocity (+ 95% confidence limits) for the three clades were 0.09 + 0.00 m s⁻¹ for the shredder, 0.25 + 0.00 m s⁻¹ for the grazer, and 0.31 + 0.01 m s⁻¹ for the filtering carnivore clade; the corresponding data for drag were (85 + 18)*10⁻⁶ N, (422 + 61)*10⁻⁶ N and (1125 + 83)*10⁻⁶ N, respectively. Adhesive friction ranged from (41.07 + 53.03)*10⁻⁶ N in D. franzi to (255.24 + 216.87)*10⁻⁶ N in D. chrysotus. Except in D. franzi and D. dudor adhesive friction was always well below drag force, indicating that submerged weight alone was not sufficient to stabilize the larvae in their hydraulic environment. Reynolds numbers varied between 0 in D. franzi and D. alpinus, and 12,634 in D. katagelastos, with 7% of the total in the laminar (R < 500), 30% in the transitional (R = 500–2000), and 61% in the fully turbulent stage (R > 2000). Froude numbers (Fr) varied from 0 to 2.97. The two Drusus species of the shredder clade and three out of four species of the grazer clade were exposed to subcritical Fr < 1, one species of the grazer clade and two out of three species of the filtering clade to supercritical Froude numbers >1.

在位于Mühlviertel（上奥地利州），Koralpe（奥地利克恩顿州）以及奥地利和意大利阿尔卑斯山的春季初生小型上游水域中研究了九种德鲁斯（Trichoptera）的最终幼虫的水生生态位描述符。。种研究覆盖Drusinae的所有三个分支：切碎机进化枝（德鲁苏斯弗兰西，D.鲑），则食草动物进化枝（D. biguttatus，D. chauvinianus，D. dudor，D.矶），和滤波食肉动物进化枝（d 。chrysotus，D. katagelastos，D. muelleri）。使用三脚架稳定的微型螺旋桨流量计（螺旋桨直径= 10 mm）在68个幼虫的前部中心，上游，在水深10–30 mm的矿物底物颗粒的顶部测量流速。每个数据系列均包含一个持续30 s（测量间隔= 1 s）的采样测量。总共进行了2040次单速测量。瞬时流速和阻力在68幼虫的位点改变从0到0.93米每秒^-1和0至8346×10 ^-6 分别N，。三个进化枝之间的流速和阻力有显着差异（p  <0.001）。三个进化枝的平均速度（+ 95％置信度）为0.09  +  0.00 m s ^-1对于切碎机，对于切碎机为0.25  +  0.00 m s ^-1，对于过滤食肉动物进化枝为0.31  +  0.01 m s ^-1；阻力的相应数据分别为（85  +  18）* 10 ^-6  N，（422  +  61）* 10 ^-6  N和（1125  +  83）* 10 ^-6N  。粘合剂摩擦从（41.07不等 +  53.03）×10 ^-6  N的D.弗兰西至（255.24  +  216.87）×10 ^-6  N的D. chrysotus。除了D.弗兰西和D. dudor胶粘剂的摩擦力始终远低于阻力，这表明仅靠水下重量不足以使幼虫在其液压环境中稳定。雷诺数在D. franzi和D. alpinus中为0，在D. katagelastos中为12,634，其中层流总数的7％（R  <500），过渡层的总数为30％（R  = 500-2000），以及61％处于完全动荡阶段（R  > 2000）。弗劳德数（Fr）从0到2.97不等。两种碎果树的德鲁斯种和四分之一的食草者种中的三种暴露于亚临界Fr <1，掠食性进化枝中的一种和过滤性进化枝中的三种中的两种，达到超临界弗洛德数> 1。