悦目金蛛拖牵丝力学性能的变异

蜘蛛丝作为一种具有优良机械性能的天然动物蛋白纤维,其特有的结构和机械性能与其生物学功能密切相关。由大壶状腺纺出的拖牵丝在蜘蛛的行走、建网、捕食、逃生、繁殖等多种生命活动中均发挥了重要的功能,其机械性能会受到多种内外因素相互作用的影响。本文对在不同体重、不同猎物饲养和不同营养状态3种条件下人工抽出的悦目金蛛(Argiope amoena)拖牵丝与其不同单丝间的力学性能进行了比较研究。结果表明,悦目金蛛拖牵丝的力学性能在组间、组内不同个体,以及同一个体不同丝纤维间变异都较大。随着蜘蛛个体的增大,蛛丝横截面直径逐渐增大,这会使得蛛丝的力学性能更好,便于作为救命索的拖牵丝在遇到危险时承受蜘蛛体重;蜘蛛在经过1个月的饥饿后,蛛丝在屈服点附近的力学性能并未发生显著变化,而断裂点应变和断裂能均显著减小,同时也表明无论对于作为救命索还是网丝,拖牵丝的弹性形变性能在与蛛丝相关的微观进化中要优先于塑性形变。这是蜘蛛在能量摄入受到限制时对拖牵丝的投入权衡的结果。

Variability in Tensile Properties of Dragline Silk from Argiope amoena

Spider silk is a natural animal protein fiber with excellent mechanical properties. Those biological and ecological functions required during spider's life history have shaped the silk's structures and mechanical properties. Dragline produced from major ampullate gland play most various roles for activities such as walking, building web, capturing prey escaping predators, reproduction etc. Its mechanical property may be influenced by some inner and outer factors. We examined the tensile properties of draglines from spiders(Argiope amoena)of different weights, from individuals fed by different foods, and from well-fed and starved spiders, and we also compared the mechanical property of filaments from the same silk. We found that the mechanical property of draglines from different individuals of the same group and silks from the same individual varied significantly, which made us difficult to determine the influence of various conditions (different weights, different foods, and well-fed and starved). With the increase of silk diameter and the increase of spider weight, the silks had better mechanical property, and these available silks were beneficial for escape. Compared to the mechanical property of the silks from the well-fed spiders, the breaking strain and breaking energy of the silks from the starved spiders decreased, but there was no difference found at yield point. It might be an investment strategy that elasticity had precedence over plasticity when intake energy of spider was limited.