During locomotion, insect feet endure dramatic impact force and generate adhesive force which is controlled by the architecture of the foot. The patterns of smooth attachment pads in insect feet vary widely among inse...During locomotion, insect feet endure dramatic impact force and generate adhesive force which is controlled by the architecture of the foot. The patterns of smooth attachment pads in insect feet vary widely among insect orders and families. The functional significance of the micro-structure and geometric design of insect feet remains largely unknown. In this study, we developed a two-dimensional finite element model of a grasshopper's attachment pad. Realistic geometric microstructure and material properties are applied in the biomechanical analysis of the structural behavior during contact. Here we use scanning electronic microscopy to study the microstructure of the grasshopper's pad, and then use the finite element method to calculate the deformation vector fields, contact stiffness, contact area, function of the airbag and strain fields during the contact process. The results reveal that the geometric design and material topology of a grasshopper's pads are very effective in reducing contact stiffness, increasing contact area and generating high friction force during the contact procedure. The rod-containing structure supporting the soft exocuticle makes the pads highly adaptive to various surfaces and decreases the stress inside the pads.展开更多
Leaf beetles Gastrophysa viridula have attracted recently increased research interest from various points of view, since they are： （i） pest insects in rhubarb crops; （ii） potential biocontrol agents of dock plant...Leaf beetles Gastrophysa viridula have attracted recently increased research interest from various points of view, since they are： （i） pest insects in rhubarb crops; （ii） potential biocontrol agents of dock plants Rumex spp. in grasslands; and （iii） a model species in ecological studies on insect population dynamics, biochemistry, behavior, biomechanics and biomimetics. The continuous rearing of beetles at standardized conditions may help to unify the fitness state of different individuals, allowing a better comparison of experimental results. The present communication suggests a modular space- and time-saving rearing method ofG. viridula in stackable faunariums under laboratory conditions, which has been successfully established and continuously used over the last 5 years. Several developmental stages were kept in separate boxes, and multiple generations were kept simultaneously, depending on the required number of beetles.展开更多
Geometric and micro-structure design, tribology properties of beetle joints were experimentally studied, which aimed to enlighten ideas for the joint design of MEMS.The observation by using SEM and microscopy suggeste...Geometric and micro-structure design, tribology properties of beetle joints were experimentally studied, which aimed to enlighten ideas for the joint design of MEMS.The observation by using SEM and microscopy suggested that beetle's joints consist of a concave surface matched with a convex surface. The heads of the beetles, rubbing with flat glass, were tested in fresh and dried statuses and compared with sapphire ball with flat glass. Frictional coefficient of the joint material on glass was significantly lower than that of the sapphire sphere on glass. The material of the joint cuticle for convex surface is rather stiff (the elastic modulus 4.5 Gpa) and smooth. The surface is hydrophobic (the contact angle of distilled water was 88.3° ). It is suggested here that the high stiffness of the joint material and hydrophobicity of the joint surface are parts of the mechanism minimizing friction in insect joints.展开更多
基金Supported by the National Natural Science Foundation of China (Grants Nos. 60535020, 50635030 and 50675160)the Development Plan of the State Key Fundamental Research (Grant No. 2007CB607600)
文摘During locomotion, insect feet endure dramatic impact force and generate adhesive force which is controlled by the architecture of the foot. The patterns of smooth attachment pads in insect feet vary widely among insect orders and families. The functional significance of the micro-structure and geometric design of insect feet remains largely unknown. In this study, we developed a two-dimensional finite element model of a grasshopper's attachment pad. Realistic geometric microstructure and material properties are applied in the biomechanical analysis of the structural behavior during contact. Here we use scanning electronic microscopy to study the microstructure of the grasshopper's pad, and then use the finite element method to calculate the deformation vector fields, contact stiffness, contact area, function of the airbag and strain fields during the contact process. The results reveal that the geometric design and material topology of a grasshopper's pads are very effective in reducing contact stiffness, increasing contact area and generating high friction force during the contact procedure. The rod-containing structure supporting the soft exocuticle makes the pads highly adaptive to various surfaces and decreases the stress inside the pads.
文摘Leaf beetles Gastrophysa viridula have attracted recently increased research interest from various points of view, since they are： （i） pest insects in rhubarb crops; （ii） potential biocontrol agents of dock plants Rumex spp. in grasslands; and （iii） a model species in ecological studies on insect population dynamics, biochemistry, behavior, biomechanics and biomimetics. The continuous rearing of beetles at standardized conditions may help to unify the fitness state of different individuals, allowing a better comparison of experimental results. The present communication suggests a modular space- and time-saving rearing method ofG. viridula in stackable faunariums under laboratory conditions, which has been successfully established and continuously used over the last 5 years. Several developmental stages were kept in separate boxes, and multiple generations were kept simultaneously, depending on the required number of beetles.
基金This work was supported by the Federal Ministry of Science of Germany(BMBF)grant BioFuture 0311851 to S.Gorbby the National Natural Science Foundation of China(Grant No.90205014)863 Project 2002AA 423230 to Z.D.Dai.
文摘Geometric and micro-structure design, tribology properties of beetle joints were experimentally studied, which aimed to enlighten ideas for the joint design of MEMS.The observation by using SEM and microscopy suggested that beetle's joints consist of a concave surface matched with a convex surface. The heads of the beetles, rubbing with flat glass, were tested in fresh and dried statuses and compared with sapphire ball with flat glass. Frictional coefficient of the joint material on glass was significantly lower than that of the sapphire sphere on glass. The material of the joint cuticle for convex surface is rather stiff (the elastic modulus 4.5 Gpa) and smooth. The surface is hydrophobic (the contact angle of distilled water was 88.3° ). It is suggested here that the high stiffness of the joint material and hydrophobicity of the joint surface are parts of the mechanism minimizing friction in insect joints.
