Theoretical and Applied Mechanics Program, Northwestern University, Evanston, IL 60208, USA.
Department of Mechanical Engineering, University of Texas at Austin, Austin, TX 78712, USA.
Acta Biomater. 2021 Mar 1;122:236-248. doi: 10.1016/j.actbio.2020.12.039. Epub 2020 Dec 21.
Nature's masterfully synthesized biological materials take on greater relevance when viewed through the perspective of evolutionary abundance. The fact that beetles (order Coleoptera) account for a quarter of all extant lifeforms on Earth, makes them prime exponents of evolutionary success. In fact, their forewings are acknowledged as key traits to their radiative-adaptive success, which makes the beetle elytra a model structure for next-generation bioinspired synthetic materials. In this work, the multiscale morphological and mechanical characteristics of a variety of beetle species from the Cetoniinae subfamily are investigated with the aim of unraveling the underlying principles behind Nature's adaptation of the elytral bauplan to differences in body weight spanning three orders of magnitude. Commensurate with the integral implications of size variation in organisms, a combined material, morphological, and mechanical characterization framework, across spatial scales, was pursued. The investigation revealed the simultaneous presence of size-invariant strategies (chemical compositions, layered-fibrous architectures, graded motifs) as well as size-dependent features (scaling of elytral layers and characteristic dimensions of building blocks), synergistically combined to achieve similar levels of biomechanical functionality (stiffness, energy absorption, strength, deformation and toughening mechanisms) in response to developmental and selection constraints. The integral approach here presented seeks to shed light on Nature's solution to the problem of size variation, which underpins the diversity of beetles and the living world.
从进化丰度的角度来看，自然界中精心合成的生物材料具有更大的意义。事实上，鞘翅目昆虫（鞘翅目）占地球上所有现存生命形式的四分之一，它们是进化成功的主要代表。事实上，它们的前翅被认为是它们辐射适应性成功的关键特征，这使得甲虫的鞘翅成为下一代仿生合成材料的模型结构。在这项工作中，研究了 Cetoniinae 亚科的各种甲虫物种的多尺度形态和力学特性，目的是揭示自然界对鞘翅目 bauplan 的适应性背后的基本原理，这种适应性涉及到跨越三个数量级的体重差异。与生物体尺寸变化的整体影响相一致，采用了跨空间尺度的综合材料、形态和力学特性表征框架。研究结果表明，同时存在尺寸不变的策略（化学成分、分层纤维结构、梯度图案）和尺寸相关的特征（鞘翅层的缩放和构建块的特征尺寸），这些策略协同组合，以实现类似的生物力学功能（刚度、能量吸收、强度、变形和增韧机制），以应对发育和选择的限制。这里提出的整体方法旨在揭示自然界解决尺寸变化问题的方法，这是甲虫和整个生命世界多样性的基础。
