基于四种金龟的昆虫后翅关节骨片三维形态复杂性研究

【目的】昆虫的翅非常精巧与灵活，翅脉及翅关节的形态及功能长久以来受到众多领域科学家的广泛关注。由于历史条件的限制，昆虫翅的研究主要集中在翅脉，即使少量的有关翅关节形态的研究也主要是停留在二维形态数据分析的层面上。更重要的是，各骨片内部形态结构还未见报道。本研究的目的就是为了重建翅关节骨片内部和外部复杂的三维形态结构，全面呈现利用传统形态学方法无法获得的形态学信息，进而深入探究昆虫翅的形态与功能的关系。【方法】本文利用显微CT对鞘翅目4种金龟进行了扫描，通过计算机三维重建技术，对折叠和展开状态时后翅关节各个骨片（第1, 2和3腋片及中片）的内部和外部的三维形态进行研究，展示和分析昆虫翅关节内部与外部形态结构和空间运动的复杂性。【结果】翅关节骨片的三维重建模型及虚拟切面图展示了其复杂的外部形态，主要表现在表面曲率的不均匀变化和部分结构的互相遮挡两个方面。前者主要表现骨片表面具有突起、沟槽、弯折以及外长物等。后者指各骨片均呈现了不同程度的弯折，有的弯折还会互相接触，最终形成筒状结构，这样不可避免造成部分结构被遮挡或包裹。三维重建模型的断层图显示了翅关节骨片并非是实心的结构，而是分为两层：靠近表皮的为高度骨化的外骨骼，而靠近骨片核心则为疏松的类似海绵状结构。本文还展示了各个骨片在后翅折叠状和展开状态下的空间位置，并对所研究的4个科的翅关节骨片的三维形态进行了比较。【结论】翅关节骨片具有复杂的内部和外部形态结构。关节骨片的内部海绵结构和外层强烈骨化的双层结构，可能与其尽量减小骨片的重量和节约运动能量，同时又尽量保持骨片的刚性结构的形态适应策略有关。此类形态适应在材料学、空气动力学等领域具有重要的仿生学意义。

A study of the three-dimensional morphological complexity of insect hindwing articulation based on four scarab species (Coleoptera: Scarabaeoidea)

【Aim】 Insect wings are very delicate and flexible. The morphology and function of veins and wing articulation has long aroused wide concern of scientists in many fields. Due to limitation of historical conditions, the studies of insect wings mainly focused on vein morphology. Even the small amount of wing articulation morphology studies mainly stayed on the analysis of two-dimensional data. Furthermore, there is no report on the internal structures of the sclerites of insect wing articulations. The aim of this study isto reconstruct the internal and external three-dimensional morphology of the sclerites of insect wing articulations. The entire morphological information of the very complicated three-dimensional structures will be gained which is impossible to be demonstrated using traditional research methods. Thus, the relationships between the insect wing morphology and function could be inferred. 【Methods】 Four scarab beetle species from four families of Scarabaeoidea were scanned using Micro CT. The three-dimensional morphology of sclerites of wing articulations including the 1st, 2nd and 3rd axillary plates and median plate was reconstructed and analyzed. 【Results】 The morphological complexity of sclerites of wing articulations was demonstrated with the rendering and virtual cut of the three-dimensional models. The uneven curvature changes of external surface and the overlap of some parts of sclerites were found. The former mainly includes the protrusion, groove, and bend of external surface. The latter mainly includes the contact of some parts forming a tubular structure and some structure is concealed. Furthermore, the double-layer structures of the sclerites of wing articulations were found. The external layer is highly dense and solid, while the internal is a sponge-like structure. The relative spatial positions of folded and unfolded states of the sclerites were displayed in a three-dimensional way. The morphology of wing articulations of four species was compared. 【Conclusion】 Insect wing articulations are complex in internal and external morphology. Double-layer structure and the sponge-like internal structure may be related to the morphological adaptation strategy on minimizing the weight, saving energy in the movement and maintaining a rigid structure at the same time. Such morphological adaptations may have bionics significance for materials science, aerodynamics and some other fields.