横纹金蛛捕食经验对其丝纤维力学行为与性能的影响

Effect of the Prey Experience on Tensile Behavior and Properties of Silk Fiber from Argiope bruennichi

蛛网是蜘蛛的捕食工具,蛛网网丝的结构与性能不仅影响蜘蛛的捕食效率,也关系着蜘蛛的捕食投入。本文利用单纤维电子强力仪研究横纹金蛛(Argiope bruennichi)室内捕食面包虫(Tenebrio molitor)时上前与返回捕食拖丝的力学性能以及捕食经验对圆网半径丝修补前后的力学性能的影响。结果表明,与上前捕食拖丝相比,返回捕食拖丝减小了弹性区的投入,增加了屈服区和加强区的投入,且返回时捕食拖丝更具柔韧性。整体而言,与初始半径丝相比,在未喂食面包虫的条件下,网的半径修补丝增加了力学性能的投入;而在喂食面包虫的条件下,网的半径修补丝减少了力学性能的投入。所测试丝样中出现了两种类型的蛛丝力学行为:一种为典型的蛛丝力学行为;另外一种为似黏流性材料的力学行为,其反映的是满足蛛丝耗散猎物或自身下降时动能的另外一种力学性能的策略。本研究表明蜘蛛能根据其捕食经验遵循Cost-Benefit原则对蜘蛛丝的力学性能进行调节,从而调整捕食投入。

Spider webs are used to capture prey,therefore the structure and mechanical properties of the webs can affect the efficiency of prey capture and foraging investment. Is there an effect of the prey experience on tensile behavior and properties of silk fiber？ In this paper,tensile properties of forward and returning preying dragline silk and the effects of the predator experience on tensile properties of radius silk before and aftermending were examined and investigated using electric single-fiber tensile apparatus when Argiope bruennichi preyed on Tenebrio molitor. The data dealt with Spass 17. 0. Fig. 1 and table 1 show that compared with forward preying dragline silk（ Du= 12. 2 ± 2. 5 mm,Fu= 5. 12 ± 0. 53 cN）,returning preying dragline silk reduces investment in the elastic region and increases investment in the yield and hardening region（ Du= 23. 94± 0. 50 mm,Fu= 8. 07 ± 3. 70 cN,PD= 0. 001 ＆lt; 0. 010,PF= 0. 242 ＆gt; 0. 050）,moreover returning preying dragline silk presents higher toughness. Fig. 2 and table 2 show that compared with initial radius silk（ Du=7. 18 mm,Fu= 0. 51 cN）,radius mending silk under no feeding T. molitor increases investment of tensile properties（ Du= 9. 73 ± 0. 94 mm,Fu= 3. 37 ± 0. 85 cN）. However,radius mending silk under feeding T.molitor reduces investment of tensile properties（ control silk： Du= 21. 93 mm,Fu= 9. 88 cN,mending silk：Du= 18. 47 ± 3. 43 mm,Fu = 3. 01 ± 1. 40 cN）. In addition,Fig. 1 and 2 also demonstrate that two types of tensile behaviors present in tested samples of spider silk： one is the typical of tensile behavior similar to dragline silk; another one is the tensile behavior of material of the viscous flow,which reflects the tensile properties,is the strategy of another kind of materials. It can content with the demand that spider silk dissipate absorb kinetic energy of prey and spider itself when it fall down. This study shows that spider can adjust mechanical properties of spider silk according to its prey experience following cost-benefit principles in order to adjust prey inputs.