Functional Morphology and Biomechanics, Institute of Zoology, Kiel University, Kiel, Germany.
Soft Matter. 2019 Oct 23;15(41):8272-8278. doi: 10.1039/c9sm01687b.
The cuticle plays an important role in the evolutionary success of insects. Many studies on insect cuticles have reported a soft, resilin-rich endocuticle. However, a recent study indicated the presence of a sclerotised endocuticle in the weevil Pachyrhynchus sarcitis kotoensis, which contradicts former knowledge. To understand the degree of sclerotisation in the endocuticle of the weevil and its potential function, we first examined the endocuticle by microscopic and staining techniques. We next performed mechanical tests to measure the material properties of the endocuticle, and numerical simulations to predict the structural effect of the sclerotisation. Our results provide the first evidence of the existence of a sclerotised endocuticle and its remarkable function in improving the mechanical stability of the cuticle. This study highlights the finding of a high degree of sclerotisation in the stiff endocuticle of the weevil, especially the matrix surrounding the fibres. This novel case brings new understanding of cuticle properties and gives promising insights into biomaterial design.
表皮层在昆虫的进化成功中起着重要作用。许多关于昆虫表皮层的研究报告表明，其富含柔软的弹性蛋白的内表皮层。然而，最近的一项研究表明，在象鼻虫 Pachyrhynchus sarcitis kotoensis 中存在着硬化的内表皮层，这与之前的知识相矛盾。为了了解象鼻虫内表皮层的硬化程度及其潜在功能，我们首先通过显微镜和染色技术对内表皮层进行了检查。接下来，我们进行了机械测试来测量内表皮层的材料特性，并进行了数值模拟来预测硬化的结构效应。我们的研究结果首次提供了存在硬化内表皮层的证据，以及其在提高表皮机械稳定性方面的显著功能。本研究突出了在象鼻虫坚硬的内表皮层中发现的高度硬化程度，尤其是纤维周围的基质。这种新的情况为表皮特性提供了新的认识，并为生物材料设计提供了有前景的见解。
