Department of Functional and Evolutionary Ecology, Estación Experimental de Zonas Aridas, CSIC, Ctra. de Sacramento S/N, La Cañada de San Urbano, 04120 Almeria, Spain.
J Theor Biol. 2010 Oct 7;266(3):430-5. doi: 10.1016/j.jtbi.2010.06.031. Epub 2010 Jun 30.
Silk is known for its strength and extensibility and has played a key role in the radiation of spiders. Individual spiders use different glands to produce silk types with unique sets of proteins. Most research has studied the properties of major ampullate and capture spiral silks and their ecological implications, while little is known about minor ampullate silk, the type used by those spider species studied to date for bridging displacements. A biomechanical model parameterised with available data shows that the minimum radius of silk filaments required for efficient bridging grows with the square root of the spider's body mass, faster than the radius of minor ampullate silk filaments actually produced by spiders. Because the morphology of spiders adapted to walking along or under silk threads is ill suited for moving on a solid surface, for these species there is a negative relationship between body mass and displacement ability. As it stands, the model suggests that spiders that use silk for their displacements are prevented from attaining a large body size if they must track their resources in space. In particular, silk elasticity would favour sexual size dimorphism because males that must use bridging lines to search for females cannot grow large.
丝以其强度和可拉伸性而闻名，在蜘蛛的辐射中发挥了关键作用。个体蜘蛛使用不同的腺体来产生具有独特蛋白质组合的丝类型。大多数研究都研究了主要壶腹和捕获螺旋丝的性质及其生态意义，而对小壶腹丝知之甚少，小壶腹丝是迄今为止用于桥接位移的那些蜘蛛物种所使用的丝类型。用现有数据参数化的生物力学模型表明，用于有效桥接的丝纤维的最小半径随蜘蛛体质量的平方根增长，快于蜘蛛实际产生的小壶腹丝纤维的半径。由于适应沿丝线或在丝线下行走的蜘蛛的形态不适合在固体表面上移动，对于这些物种，体质量和位移能力之间存在负相关关系。目前，该模型表明，如果蜘蛛必须在空间中跟踪其资源，那么它们用于位移的丝会阻止它们获得大的体型。特别是，丝的弹性将有利于性二态性，因为必须使用桥接线来寻找雌性的雄性不能长得很大。
