Structure and mechanics of the tarsal chain in the hornet, Vespa crabro (Hymenoptera: Vespidae):: implications on the attachment mechanism
Structure and mechanics of the tarsal chain in the hornet, Vespa crabro (Hymenoptera: Vespidae):: implications on the attachment mechanism
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DOI：
10.1016/j.asd.2003.10.003
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发表时间：
2004-01-01
影响因子：
2
通讯作者：
Gorb, S
中科院分区：
文献类型：
--
作者：
Frantsevich, L;Gorb, S
大黄蜂跗骨上的两种组合机制适合于附着在基底上：基于摩擦的（爪和刺）和基于粘附的（arolium）。有两个范围的基板粗糙度最佳的附着，要么非常光滑或非常粗糙。存在小但非零尺寸的衬底晶粒的中间范围，其中这两种机制都失效。基质颗粒的最佳尺寸为50-100 μ m。当表面不规则性被夹在相对腿的爪之间时，实现了对基板的最大保持。在这样的姿势下，昆虫可以承受几乎是自身重量25倍的外力，跗链是整个附着机制的重要组成部分。胫骨-跗骨-前跗骨运动链中的关节为单髁关节。三个跗骨肌和一个爪牵开肌头起源于胫骨。牵拉牵开肌腱时，跗骨在平面内弯曲。跗骨运动链的所有元素都有一个主动自由度。跗关节间关节点和爪牵开器的腱之间的距离（75-194 μ m）对应于腱行进的每1-3 μ m的牵拉距离的1度的效率。爪每移动4.3-5.0 μ m的距离，爪就转动10 °左右。关节的运动链除了在手骨基部的关节外，缺少真实的髁状关节。其他部分则由膜状角质层的弹性传递连接。行走的大黄蜂靠在延长的跗骨的远侧跗节上。如果跗骨内的牵开肌腱固定，跗节的被动伸展可能会被爪屈曲所取代。当牵开器肌腱收紧时，用测力仪测量的跗骨链刚度增加。很可能，对肌腱的拉力会压缩跗节，增加关节内髁周围波纹表面接触区域内的摩擦力。(C)2003爱思唯尔有限公司。保留所有权利。
Two combined mechanisms on the hornet tarsus are adapted to attachment to the substrate: a friction-based (claws and spines) and an adhesion-based one (arolium). There are two ranges of substrate roughness optimal for attachment, either very smooth or very rough. There is an intermediate range of substrate grains of small but-non-zero size, where both of these mechanisms fail. The optimal size of substrate grains for hornet grasping was 50-100 mum. Maximal hold to the substrate was achieved when surface irregularities were clamped between the claws of opposite legs. In such a position, the insect could withstand an external force which was almost 25 times larger than its own weight.The tarsal chain is an important part of the entire attachment mechanism. The articulations in the kinematic chain of tibia-tarsus-pretarsus are monocondylar. Three tarsal muscles and one head of the claw retractor muscle originate in the tibia. On pull to the retractor tendon, the tarsus bends in a plane. All elements of the tarsal kinematic chain have one active degree of freedom. The distance between the intertarsomeric articulation point and the tendon of the claw retractor (75-194 mum) corresponds to an efficiency of 1degrees per 1-3 mum of pulling distance travelled by the tendon. The claw turns about 1degrees per 4.3-5.0 mum of pulling distance travelled by the unguitractor.The arolium turns forward and downward simultaneously with flexion of the claws. The kinematic chain of the arolium lacks real condylar joints except the joint at the base of the manubrium. Other components are tied by flexible transmissions of the membranous cuticle.The walking hornet rests on distal tarsomeres of extended tarsi. If the retractor tendon inside the tarsus is fixed, passive extension of the tarsomeres might be replaced by claw flexion. Tarsal chain rigidity, measured with the force tester, increased when the retractor tendon was tightened. Probably, pull to the tendon compresses the tarsomeres, increasing friction within contacting areas of rippled surfaces surrounding condyles within articulations. (C) 2003 Elsevier Ltd. All rights reserved.