Form-function relationships of head capsules of early split biting-chewing insects in a phylogenetic framework

有翼昆虫，如蜻蜓和蚂蚁(=古翅目)、蝗虫及其盟友(=多新翅目)或斑腿蝗属(=Psocodea)，大多具有相同主要结构的咬合咀嚼下巴。与基本口器结构中的这种相对均匀相比，头部胶囊在形状上表现出很大的多样性。这种头囊形状多样性的原因，它对头部生物力学的影响，以及它可能与生态因素的相互作用尚不清楚。因此，该项目将机械地研究早期咬咬昆虫体内不同头壳类型的多样性，以评估不同的头部形状如何影响整体机械性能，并最终影响头部系统的进化适应性。总的假设是，咬咬昆虫体内存在着不同的形态和机械空间，它们更依赖于生态位，而不是共同的祖先。此外，预计在咬咬进化过程中，这些不同的机械空间只允许有限数量的形状变化轨迹。将用几何形态计量学定量分析大范围的古翅目、多翅目和拟码目的(&gt；400种)头部形状的变化。然后利用多体动力学分析和有限元分析对覆盖主要头囊形态的一个子集(~43个物种)进行生物力学模拟。材料特性、肌肉特性和咬合力测量将作为生物力学建模的输入变量，以确保在计算机模型中准确地表示活体力学。该项目还将进一步考虑一般生态位，如食物光谱、狩猎类型等，以在系统发育框架内测试它们对头部力学和形状变化的影响。最后，对咬合咀嚼的理论机械性能图景与真实物种所占据的实际性能图景进行建模，将允许识别在咬合-咀嚼系统的进化和多样化过程中头部形状的变化轨迹和涉及的权衡。因此，这些结果将加深我们对昆虫进化的理解，该项目确定了哪些机械因素使昆虫成为如此成功的取食者，以及它们的头部为什么以及如何进化成如此多不同的类型。

Winged insects such as dragonflies and mayflies (=Palaeoptera), grasshoppers and allies (=Polyneoptera) or barklice (=Psocodea) mostly possess biting-chewing mandibles of the same principal construction. In contrast to this relative uniformity in basic mouthpart construction, head capsules show a great variety in shape. The reasons for this head capsule shape diversity, its consequences for head biomechanics and finally its likely interplay with ecological factors are unknown. The project will therefore investigate the variety of different head capsule types within early biting-chewing insects mechanically, in order to assess how different head shapes influence overall mechanical performance and, finally, the evolutionary fitness of the head system. The overall hypothesis is that distinct morpho- and mechanospaces within biting-chewing insects exist, which are more dependent on the ecological niche than on common ancestry. Moreover it is expected that these distinct mechanospaces permited only a limited number of shape change trajectories during the evolution of biting-chewing.The 3D head shape variation of a wide range of Palaeoptera, Polyneoptera and Psocodea (>400 species) will be quantitatively analysed with geometric morphometrics. Biomechanical simulation will then be carried out on a subset (~43 species) covering the main head capsule morphotypes using multibody dynamics analysis and finite element analysis. Material property, muscle property, and bite force measurements will serve as input variables for the biomechanical modelling to ensure an accurate representation of in vivo mechanics in the in silico models. The project will furthermore take into account the general ecological niche such as food spectrum, hunting type, etc. in order to test their influence on head mechanics and shape variation in a phylogenetic framework. Finally, modelling of the theoretical mechanical performance landscape of biting-chewing in relation to the actual performance landscape occupied by real species will allow to identify head shape change trajectories and involved trade-offs during the evolution and diversification of the biting-chewing system. The results will thus refine our understanding of insect evolution, with the project identifying which mechanical factors made insects such extraordinarily successful feeders, and why and how their heads evolved into so many different types.