University of Akron and Integrated Biosciences Program, University of Akron, Akron, OH 44325-3908, USA.
J Exp Biol. 2013 Oct 1;216(Pt 19):3606-10. doi: 10.1242/jeb.084236. Epub 2013 Jun 20.
Like many biomaterials, spider silk responds to water through softening and swelling. Major ampullate silk, the main structural element of most prey capture webs, also shrinks dramatically if unrestrained or develops high tension if restrained, a phenomenon called 'supercontraction'. While supercontraction has been investigated for over 30 years, its consequences for web performance remain controversial. Here, we measured prey capture performance of dry and wet (supercontracted) orb webs of Argiope and Nephila using small wood blocks as prey. Prey capture performance significantly increased at high humidity for Argiope while the improvement was less dramatic for Nephila. This difference is likely due to Argiope silk supercontracting more than Nephila silk. Web deflection, measured as the extension of the web upon prey impact, also increased at high humidity in Argiope, suggesting that silk softening upon supercontraction explains the improved performance of wet webs. These results strongly argue that supercontraction is not detrimental to web performance.
像许多生物材料一样，蜘蛛丝会通过软化和膨胀来响应水。主要的壶状丝是大多数猎物捕捉网的主要结构元素，如果不受约束，它会剧烈收缩，如果受到约束，它会产生高张力，这种现象称为“超收缩”。虽然超收缩已经研究了 30 多年，但它对网性能的影响仍然存在争议。在这里，我们使用小木块作为猎物，测量了干燥和湿润（超收缩）的蛛网的猎物捕获性能。对于 Argiope 来说，高湿度下的猎物捕获性能显著提高，而对于 Nephila 来说，改善幅度较小。这种差异可能是由于 Argiope 丝的超收缩程度超过了 Nephila 丝。在 Argiope 中，网的挠度（即猎物撞击时网的延伸）也随着高湿度而增加，这表明超收缩时丝的软化解释了湿网性能的提高。这些结果强烈表明，超收缩对网性能没有不利影响。
