Evidence for a material gradient in the adhesive tarsal setae of the ladybird beetle Coccinella septempunctata
Evidence for a material gradient in the adhesive tarsal setae of the ladybird beetle Coccinella septempunctata
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DOI：
10.1038/ncomms2576
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发表时间：
2013-04-01
影响因子：
16.6
通讯作者：
Gorb, Stanislav N.
中科院分区：
文献类型：
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作者：
Peisker, Henrik;Michels, Jan;Gorb, Stanislav N.
为了使昆虫能够有效地附着在表面上，其腿远端的粘合垫必须建立大的接触面积。如果是毛状粘性垫，则需要形成接触的刷毛具有柔韧性，称为粘性跗骨刚毛。然而，太柔韧的刚毛会具有较低的机械稳定性，导致垫的附着能力降低。在这里，我们发现瓢虫甲虫 Coccinella septempunctata 的粘性跗骨刚毛在材料成分和沿其长度的特性方面具有明显的梯度。杨氏模量范围从尖端的 1.2MPa（我们发现其中掺入了高比例的弹性蛋白节肢素）到刚毛基部的 6.8GPa。这些梯度可能代表了一种进化优化，它可以有效适应粗糙表面，同时防止刚毛横向塌陷，从而提高粘合剂系统的性能。
For an insect to be able to efficiently attach to surfaces, the adhesive pads on the distal parts of its legs must establish large contact areas. In case of hairy adhesive pads this requires flexibility of the contact-forming bristles, called adhesive tarsal setae. However, too flexible setae would have a low mechanical stability resulting in a decreased attachment ability of the pads. Here we show that the adhesive tarsal setae of the ladybird beetle Coccinella septempunctata feature pronounced gradients in the material composition and properties along their length. The Young's modulus ranges from 1.2MPa at the tips, where we found the incorporation of high proportions of the elastic protein resilin, to 6.8 GPa at the bases of the setae. These gradients likely represent an evolutionary optimization, which increases the performance of the adhesive system by enabling effective adaptation to rough surfaces while simultaneously preventing lateral collapse of the setae.