The bamboo weevil beetle, Cyrtotrachelus buqueti, has evolved a particular flight pattern. When crawling, the beetle folds the flexible hind wings and stuffs under the rigid elytra. During flight, the hind wings are deployed through a series of deployment joints that are passively driven by flapping forces. When the hind wings are fully expanded, the unfolding joint realises self-locking. At this time, the hind wings act as a folded wing membrane and flap simultaneously with the elytra to generate aerodynamics. The functional characteristics of the elytra of the bamboo weevil beetle were investigated, including microscopic morphology, kinematic properties and aerodynamic forces of the elytra. In particular, the flapping kinematics of the elytra were measured using high-speed cameras and reconstructed using a modified direct linear transformation algorithm. Although the elytra are passively flapped by the flapping of the hind wings, the analysis shows that its flapping wing trajectory is a double figure-eight pattern with flapping amplitude and angle of attack. The results show that the passive flapping of elytra produces aerodynamic forces that cannot be ignored. The kinematics of the elytra suggest that this beetle may use well-known flapping mechanisms such as a delayed stall and clap and fling.

中文翻译：

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竹象甲甲虫 Cyrtotrachelus buqueti 刚性鞘翅的功能特征。

竹象甲甲虫 Cyrtotrachelus buqueti 已经进化出一种特殊的飞行模式。爬行时，甲虫将灵活的后翅折叠起来，并在坚硬的鞘翅下塞满东西。在飞行过程中，后翼通过一系列由拍动力被动驱动的展开关节展开。当后翅完全展开时，展开接头实现自锁。此时，后翅充当折叠的翼膜并与鞘翅同时拍打以产生空气动力学。研究了竹象甲甲虫鞘翅的功能特性，包括鞘翅的微观形态、运动学特性和气动力。尤其是，使用高速摄像机测量鞘翅的拍动运动学，并使用改进的直接线性变换算法进行重建。虽然鞘翅是通过后翅的拍动来被动拍动的，但分析表明，它的扑翼轨迹是具有扑动幅度和迎角的双八字形图案。结果表明，鞘翅的被动拍动产生了不可忽视的气动力。鞘翅的运动学表明这种甲虫可能使用众所周知的扑动机制，例如延迟失速和拍打和甩动。结果表明，鞘翅的被动拍动产生了不可忽视的气动力。鞘翅的运动学表明这种甲虫可能使用众所周知的扑动机制，例如延迟失速和拍打和甩动。结果表明，鞘翅的被动拍动产生了不可忽视的气动力。鞘翅的运动学表明这种甲虫可能使用众所周知的扑动机制，例如延迟失速和拍打和甩动。