Wolff Jonas O, Řezáč Milan, Krejčí Tomáš, Gorb Stanislav N
Functional Morphology and Biomechanics, Zoological Institute, Kiel University, Am Botanischen Garten 1-9, Kiel D-24118, Germany
Behavioural Ecology, Department of Biological Sciences, Macquarie University, Sydney, NSW 2109, Australia.
J Exp Biol. 2017 Jun 15;220(Pt 12):2250-2259. doi: 10.1242/jeb.154682.
Foraging is one of the main evolutionary driving forces shaping the phenotype of organisms. In predators, a significant, though understudied, cost of foraging is the risk of being injured by struggling prey. Hunting spiders that feed on dangerous prey like ants or other spiders are an extreme example of dangerous feeding, risking their own life over a meal. Here, we describe an intriguing example of the use of attachment silk (piriform silk) for prey immobilization that comes with the costs of reduced silk anchorage function, increased piriform silk production and additional modifications of the extrusion structures (spigots) to prevent their clogging. We show that the piriform silk of gnaphosids is very stretchy and tough, which is an outstanding feat for a functional glue. This is gained by the combination of an elastic central fibre and a bi-layered glue coat consisting of aligned nanofibrils. This represents the first tensile test data on the ubiquitous piriform gland silk, adding an important puzzle piece to the mechanical catalogue of silken products in spiders.
觅食是塑造生物体表型的主要进化驱动力之一。在捕食者中，觅食的一个重大（尽管研究不足）代价是有被挣扎的猎物伤害的风险。以蚂蚁或其他蜘蛛等危险猎物为食的狩猎蜘蛛就是危险进食的极端例子，为了一顿饭而冒生命危险。在此，我们描述了一个有趣的例子，即利用附着丝（梨形丝）固定猎物，这伴随着丝锚固功能降低、梨形丝产量增加以及对挤出结构（纺管）进行额外改造以防止堵塞的代价。我们表明，幽灵蛛科蜘蛛的梨形丝非常有弹性且坚韧，对于一种功能性胶水来说，这是一项了不起的成就。这是通过弹性中央纤维和由排列的纳米纤维组成的双层胶水层的结合实现的。这代表了关于普遍存在的梨形腺丝的首个拉伸测试数据，为蜘蛛丝制品的力学目录增添了重要的一块拼图。
