Abstract Pupae of numerous Papilionidae and Nymphalidae produce twitter sounds when wriggling in response to mechanical stimulation. The structural basis comprises distinct pairs of sound-producing organs (SPOs) located at intersegmental membranes of the abdomen. They differ—as the twitters do—in sampled taxa of Papilioninae, Epicaliini, and Heliconiini. The opposing sculptured cuticular sound plates (SPs) of each SPO appear structurally the same but are actually mirror-images of each other. Results suggest that sounds are not generated by stridulation (friction of a file and a scraper) but when these inversely sculptured and interlocking surfaces separate during pupal wriggling, representing a stick-slip mechanism. Twitter sounds comprise series of short broadband pulses with the main energy in the frequency range 3–13 kHz; they can be heard by humans but extend into ultrasonic frequencies up to 100 kHz.

中文翻译：

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蝴蝶和蛱蝶（鳞翅目）的 Twitter 蛹：新的结构和声音

摘要 许多凤蝶科和蛱蝶科的蛹在响应机械刺激时蠕动时会发出叽叽喳喳的声音。结构基础包括位于腹部节间膜的不同对的发声器官 (SPO)。它们在 Papilioninae、Epicaliini 和 Heliconiini 的采样分类群中有所不同——就像推特一样。每个 SPO 的相对雕刻表皮声板 (SP) 在结构上看起来相同，但实际上是彼此的镜像。结果表明，声音不是由颤动（锉刀和刮刀的摩擦）产生的，而是当这些反向雕刻和互锁的表面在蛹蠕动期间分离时产生的，这代表了一种粘滑机制。Twitter 声音由一系列短的宽带脉冲组成，主要能量在 3-13 kHz 的频率范围内；