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Abstract：
The mandibles are among the most important appendages of insects\' mouthparts. Their morpho-functional organization is correlated with the variation in dietary preferences. In this study, we investigated the ultrastructural organization and metal composition of the mandibles of two ladybird species with different dietary habits: Harmonia axyridis (an entomophagous species) and Subcoccinella vigintiquatuorpunctata (a phytophagous species). The ultrastructural organization was studied using Scanning and Transmission Electron Microscopy, whereas the metal composition was investigated using Energy-Dispersive X-ray spectroscopy (EDX). Significant differences were observed in the general organization and metal enrichment pattern between the two species. The mandibles of H. axyridis are large and present a molar part with two teeth, with the apical one showing a bifid apex. In contrast, S. vigintiquatuorpunctata exhibited a molar region with several teeth on its apical part. The study revealed significant differences in metal content between the teeth and the prostheca of H. axyridis. Mn was the most abundant element in teeth, whereas Cl was more abundant in the prostheca. In the case of S. vigintiquatuorpunctata, Si was the most abundant element in the prostheca, while Mn was more present in the teeth. A comparison between the two species revealed that both teeth and prostheca showed significant variation in the elemental composition. These findings underscore the role of dietary preferences in shaping the structural and metal composition variations in the mandibles of these two ladybird species.
摘要：
下颌骨是昆虫口器最重要的附属物之一。它们的形态功能组织与饮食偏好的变化相关。在这项研究中,我们研究了两种饮食习惯不同的瓢虫的下颌骨的超微结构和金属组成：Harmoniaaxyridis（一种食虫物种）和Subcoccinellavigintiquatuorpunctata（一种植食性物种）。使用扫描和透射电子显微镜研究了超微结构组织，而金属组成是使用能量色散X射线光谱（EDX）研究的。两种物种之间的一般组织和金属富集模式存在显着差异。H.axyridis的下颌骨很大，并且有两个牙齿的磨牙部分，顶端显示双裂顶端。相比之下,S.vigintiquatuorpunctata表现出一个磨牙区域，其顶端有几颗牙齿。研究表明，H.axyridis的牙齿和假体之间的金属含量存在显着差异。Mn是牙齿中含量最高的元素,而Cl在假体中更丰富。在vigintiquatuorpunctata的情况下，Si是假肢中最丰富的元素，而Mn则更多地存在于牙齿中。这两个物种之间的比较表明，牙齿和假肢的元素组成均显示出显着变化。这些发现强调了饮食偏好在塑造这两种瓢虫下颌骨结构和金属组成变化中的作用。
