Liu Sipei, Liu Xiaokun, Wang Xieshuang, Li Wenjie, Liu Xin, Ge Siqin
State Key Laboratory of Animal Biodiversity Conservation and Integrated Pest Management, Institute of Zoology, Chinese Academy of Sciences, Beijing 100101, China.
University of Chinese Academy of Sciences, Beijing 100101, China.
Insects. 2025 Jun 11;16(6):618. doi: 10.3390/insects16060618.
Flight loss has independently evolved across nearly all winged insect orders. Comparing the thoracic structures of flightless insects with those of their flight-capable relatives can reveal key characteristics linked with flight. Although flight loss has been widely studied in beetles, exploration of this phenomenon has been limited to taxonomic and geographic distribution studies in the species-rich family Chrysomelidae, with little analysis of thoracic anatomical structures. This study employs a suite of morphological techniques to examine the thoracic structures of two flightless beetle species : and , originating from desert and temperate regions, respectively. A comparison between the two flightless species reveals that has fewer tergo-pleural muscles involved in elytral movement likely to save water, but more muscles that contribute to stabilizing larger body structures. Meanwhile, differences are also observed in the elytral base, the anterior corner of the mesal suture, and the setae on the meso-inner region of the epipleuron. Compared to other flight-capable chrysomelid beetles, apart from the absence of flight-related muscles, the two flightless beetles exhibit similar thoracic skeletal structures. The absence of lateral cervical sclerites, along with the presence of muscles Idvm4, 5 and Itpm5, could enhance head mobility as a compensatory adaptation doe the loss of flight capability. Additionally, the greater number of tergo-pleural muscles in the mesothorax of could suggest that its elytra serve a specialized function. Compared to other flightless beetles, aside from the similarly reduced flight muscles, these two species have relatively intact thoracic skeletons. Further data on habitat, functional compensation and other related factors are needed to compare their evolutionary processes with those of other flightless beetles.
飞行能力的丧失在几乎所有有翅昆虫目中都独立进化而来。将无飞行能力昆虫的胸部结构与其有飞行能力的近亲进行比较，可以揭示与飞行相关的关键特征。尽管在甲虫中对飞行能力丧失的研究很广泛，但对这一现象的探索仅限于物种丰富的叶甲科的分类学和地理分布研究，对胸部解剖结构的分析很少。本研究采用一系列形态学技术来检查两种无飞行能力甲虫物种的胸部结构：分别来自沙漠和温带地区的[物种一]和[物种二]。对这两种无飞行能力的物种进行比较发现，[物种一]参与鞘翅运动的背板胸膜肌较少，这可能是为了节约用水，但有助于稳定更大身体结构的肌肉较多。同时，在鞘翅基部、中缝前角和缘折内侧区域的刚毛上也观察到了差异。与其他有飞行能力的叶甲科甲虫相比，除了没有与飞行相关的肌肉外，这两种无飞行能力的甲虫表现出相似的胸部骨骼结构。没有外侧颈片，以及存在Idvm4、5和Itpm5肌肉，可能会增强头部的活动能力，作为对飞行能力丧失的一种补偿适应。此外，[物种二]中胸背板胸膜肌数量较多，这可能表明其鞘翅具有特殊功能。与其他无飞行能力的甲虫相比，除了飞行肌肉同样减少外，这两个物种的胸部骨骼相对完整。需要关于栖息地、功能补偿和其他相关因素的进一步数据，以将它们的进化过程与其他无飞行能力的甲虫进行比较。
