Functional Morphology and Biomechanics, Institute of Zoology, Kiel University, Kiel, Germany.
J Morphol. 2023 Jun;284(6):e21590. doi: 10.1002/jmor.21590.
Prehensile raptorial forelegs are prey capturing and grasping devices, best known for praying mantises (Mantodea) within insects. They show strong morphological and behavioral adaptations toward a lifestyle as generalist arthropod predators. In the past, few species of Mantodea were investigated, concerning morphological variability of the raptorial forelegs. Especially the knowledge of foreleg anatomy in the light of functional and comparative morphology is scarce. Our comparative approach is based on the, for arthropods very common, "female-biased sexual size dimorphism" (SSD) that occurs in almost every Mantodea species. Within Mantodea, this SSD is likely leading to a shift of the exploited ecological niche between male and female individuals due to changes in, for example, the possible prey size; which might be reflected in the chosen ecomorphs. In this context, we analyzed the musculature of the raptorial forelegs of female and male specimens in five different species with varying SSD, using high-resolution microcomputed tomography and dissection. We were able to confirm the presence of 15 extrinsic and 15 intrinsic muscles-including one previously undescribed muscle present in all species. Thus, presenting a detailed description and illustrative three-dimensional anatomical visualization of the musculature in Mantodea. Interestingly, almost no observable differences were found, neither between species, nor between the sexes. Furthermore, we homologized all described muscles, due to their attachment points, to the comprehensive nomenclature established by Friedrich and Beutel (2008), discussed potential functionality of the muscles and possible homologies to the neuropteran Mantispa styriaca (Büsse et al., 2021) and the newly introduced leg nomenclature by Aibekova et al. (2022). By elucidating the anatomy, particularly in the context of functionality and SSD, our results complement previous knowledge of the raptorial forelegs, and facilitate a better understanding of the underlying biomechanical system of the predatory strike, and ultimately, a future comparison to other insect taxa.
捕食性捕捉和抓握的前肢是一种器官，最著名的是昆虫中的螳螂目（Mantodea）。它们在形态和行为上表现出强烈的适应性，以适应作为节肢动物捕食者的生活方式。过去，对螳螂目的少数物种进行了研究，涉及到捕食性前肢的形态变异性。特别是在功能和比较形态学方面，对前肢解剖结构的了解还很缺乏。我们的比较方法基于在几乎每一个螳螂目中都存在的“雌性偏性性二型性”（SSD），这在节肢动物中非常普遍。在螳螂目中，这种 SSD 可能会导致由于可能的猎物大小等因素的变化，雄性和雌性个体之间的生态位发生转变；这可能反映在选择的生态形态上。在这方面，我们使用高分辨率微计算机断层扫描和解剖分析了五种不同 SSD 物种的雌性和雄性标本的捕食性前肢的肌肉组织。我们能够确认 15 块外在和 15 块内在肌肉的存在，包括所有物种中都存在的一块以前未描述的肌肉。因此，本文提供了螳螂目肌肉组织的详细描述和直观的三维解剖可视化。有趣的是，我们既没有发现物种之间的差异，也没有发现性别之间的差异。此外，由于其附着点，我们将所有描述的肌肉与 Friedrich 和 Beutel（2008 年）建立的全面命名法进行了同源化，讨论了肌肉的潜在功能以及与脉翅目 Mantispa styriaca（Büsse 等人，2021 年）和 Aibekova 等人引入的新腿部命名法（2022 年）的可能同源性。通过阐明解剖结构，特别是在功能和 SSD 的背景下，我们的研究结果补充了以前对捕食性前肢的认识，并有助于更好地理解捕食性攻击的潜在生物力学系统，最终可以与其他昆虫类群进行比较。
