猪笼草捕虫笼蜡质滑移区捕获刚毛类昆虫机理的实验研究

Insects can crawl on various smooth and rough surfaces owing to their special adsorption system. However, common nepenthes possess an ability to resist the adsorption of insects, and to capture them taking advantage of waxy slip zone in pitchers. It is helpful to develop an anti-adsorption surface based on investigating the mechanism of capturing insects. The aim of this project is to study the mechanism how nepenthes capture insects with fairy adhesive pads and to investigate whether the roughness of the wax crystal in waxy slip zone plays an important role in capturing the insects. Meanwhile, we will explore whether there are coupling effects between the surface anisotropy of waxy slip zone and the adhesion direction of insects with fairy adhesive pads, and whether the surface anisotropy of waxy slip zone has influence on insects with fairy adhesive pads. Furthermore, an experimental setup is expected to be established to measure the fiction force with different surface roughnesses. The traction force generated while insects crawl on the surface of nepenthes's waxy zone will be measured as well. Combining the characterations of the surface of waxy zone and adhesive pads of insects, it is expected to uncover the mechnism how nepenthes capture insects with fairy adhesive pads.

昆虫以其特有的吸附系统能够在光滑和多种粗糙表面爬行，而猪笼草却能够"拒绝"昆虫的吸附，并利用捕虫笼蜡质滑移区的特点捕获昆虫，研究其捕虫机理，有助于今后研制防吸附表面，具有潜在应用价值。本项目旨在研究猪笼草捕获毛性黏附垫昆虫的机理，考察蜡质区蜡晶体粗糙度是否是决定捕获昆虫的重要因素，同时考察蜡质滑移区表面的各向异性与刚毛类昆虫足黏附的方向性是否有耦合作用，蜡质区表面各向异性对刚毛类昆虫是否也起作用，搭建实验平台测试表面粗糙度不同时昆虫的摩擦力，以及昆虫在猪笼草蜡质区表面爬行时的牵引力，同时结合蜡质区表面及昆虫粘性垫的表征，希望能够揭示猪笼草捕获毛性黏附垫昆虫的机理。

本项目利用分子动力学研究方法探讨了表面微结构对表面润湿性以及润湿方向性的影响，研究结果表明表面微结构尺寸对表面润湿性有影响，对于亲水性表面，水的铺展表现为各向异性，表面微结构形状不同，水滴稳定后呈现不同的特殊形状。利用胶体探针技术在无针尖的探针悬臂上粘附SiO2小球，模拟昆虫单根刚毛与表面的接触，测试表面的摩擦力和粘附力，研究结果表明，表面微粗糙度能有效地减小界面间的接触面积，降低了蜡质滑移区表面的粘附力和摩擦力；蜡质滑移区超疏水特性和低表面能是降低表面粘附力和摩擦力的另一个重要因素，两者共同作用形成了猪笼草蜡质滑移区的反粘附特性。