Silk structure rather than tensile mechanics explains web performance in the moth-specialized spider, Cyrtarachne
Silk structure rather than tensile mechanics explains web performance in the moth-specialized spider, Cyrtarachne
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DOI：
10.1002/jez.2212
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发表时间：
2018-03-01
影响因子：
2.8
通讯作者：
Blackledge, Todd A.
中科院分区：
文献类型：
--
作者：
Diaz, Candido;Tanikawa, Akio;Blackledge, Todd A.
球网拦截并保留猎物，以便蜘蛛可以制服它们。球网由粘性的、柔顺的螺旋状捕获丝组成，这些螺旋状的捕获丝缠绕在坚固、坚硬的主壶腹丝线上。这些丝的机械性能差异之间的相互作用对于捕获猎物至关重要。大多数球网依靠昆虫接触数条径向线和捕获线来成功保留。然而，由于身体上覆盖着牺牲鳞片，飞蛾能够迅速从大多数球网中逃脱。 Cyrtarachne 球网很不寻常，因为它们包含的捕获线数量减少，而且飞蛾对单线的粘附力异常好。我们的目的是确定 Cyrtarachne 纺成的捕获螺旋线和径向线的拉伸特性如何在保留飞蛾猎物方面发挥作用。 NanoBionix UTM 用于量化鞭毛线和大壶腹线的材料特性，以测试 Cyrtarachne 的简化网结构是否伴随着其丝拉伸性能的改进。除了径向丝的高延伸性之外，丝线表现出专业程度较低的圆织者典型的拉伸特性。径向螺纹直径比鞭状螺纹小 62.5%，通常两者大致相似。我们利用拉伸数据创建了 Cyrtarachne 网的有限元模型，以研究猎物撞击过程中的能量耗散。鞭状线的大横截面积在使单个捕获线能够承受猎物冲击方面发挥了关键作用。 Cyrtarachne 不是非凡的丝绸，而是利用丝线尺寸和附着力的结构变化来促进网络功能。
Orb webs intercept and retain prey so spiders may subdue them. Orb webs are composed of sticky, compliant spirals of capture silk spun across strong, stiff major ampullate silk threads. Interplay between differences in the mechanical properties of these silks is crucial for prey capture. Most orb webs depend upon insects contacting several radial and capture threads for successful retention. Moths, however, escape quickly from most orb webs due to the sacrificial scales covering their bodies. Cyrtarachne orb webs are unusual as they contain a reduced number of capture threads and moths stick unusually well to single threads. We aimed to determine how the tensile properties of the capture spiral and radial threads spun by Cyrtarachne operate in retention of moth prey. A NanoBionix UTM was used to quantify the material properties of flagelliform and major ampullate threads to test if Cyrtarachne's reduced web architecture is accompanied by improvements in tensile performance of its silk. Silk threads showed tensile properties typical of less-specialized orb-weavers, with the exception of high extensibility in radial threads. Radial thread diameters were 62.5% smaller than flagelliform threads, where commonly the two are roughly similar. We utilized our tensile data to create a finite element model of Cyrtarachne's web to investigate energy dissipation during prey impact. Large cross-sectional area of the flagelliform threads played a key role in enabling single capture threads to withstand prey impact. Rather than extraordinary silk, Cyrtarachne utilizes structural changes in the size and attachment of silk threads to facilitate web function.