Department of Ecology and Evolutionary Biology, Brown University, 171 Meeting Street, GB 204, Providence, RI 02912, USA; Department of Integrative Biology, University of South Florida, 4202 East Fowler Avenue, SCA 110, Tampa, FL 33620, USA.
Integr Comp Biol. 2020 Oct 1;60(4):840-851. doi: 10.1093/icb/icaa110.
Animals clinging to natural surfaces have to generate attachment across a range of surface roughnesses in both dry and wet conditions. Plethodontid salamanders can be aquatic, semi-aquatic, terrestrial, arboreal, troglodytic, saxicolous, and fossorial and therefore may need to climb on and over rocks, tree trunks, plant leaves, and stems, as well as move through soil and water. Sixteen species of salamanders were tested to determine the effects of substrate roughness and wetness on maximum cling angle. Substrate roughness had a significant effect on maximum cling angle, an effect that varied among species. Substrates of intermediate roughness (asperity size 100-350 µm) resulted in the poorest attachment performance for all species. Small species performed best on smooth substrates, while large species showed significant improvement on the roughest substrates (asperity size 1000-4000 µm), possibly switching from mucus adhesion on a smooth substrate to an interlocking attachment on rough substrates. Water, in the form of a misted substrate coating and a flowing stream, decreased cling performance in salamanders on smooth substrates. However, small salamanders significantly increased maximum cling angle on wetted substrates of intermediate roughness, compared with the dry condition. Study of cling performance and its relationship to surface properties may cast light onto how this group of salamanders has radiated into the most speciose family of salamanders that occupies diverse habitats across an enormous geographical range.
附着在自然表面上的动物，无论是在干燥还是湿润的条件下，都必须在一系列的表面粗糙度范围内产生附着。泥螈科的蝾螈可以是水生的、半水生的、陆生的、树栖的、穴居的、石生的和穴居的，因此它们可能需要在岩石、树干、植物叶片和茎上攀爬和爬行，并且需要在土壤和水中移动。为了确定基质粗糙度和湿润度对最大附着力的影响，对 16 种蝾螈进行了测试。基质粗糙度对最大附着力有显著影响，而且这种影响因物种而异。中等粗糙度（粗糙度尺寸为 100-350μm）的基质对所有物种的附着力表现最差。小体型物种在光滑基质上的表现最好，而大型物种在最粗糙的基质（粗糙度尺寸为 1000-4000μm）上表现出显著的改善，可能会从光滑基质上的黏液附着转变为粗糙基质上的联锁附着。以基质喷雾和流动水流的形式存在的水会降低光滑基质上蝾螈的附着力性能。然而，与干燥条件相比，小型蝾螈在湿润的中等粗糙度基质上的最大附着力显著增加。对附着性能及其与表面特性的关系的研究，可能有助于揭示这群蝾螈是如何辐射到占据巨大地理范围的、最具物种多样性的蝾螈科的。
