An Eocene insect could hear conspecific ultrasounds and bat echolocation
An Eocene insect could hear conspecific ultrasounds and bat echolocation
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DOI：
10.1016/j.cub.2023.10.040
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发表时间：
2023-12-18
期刊：
影响因子：
9.2
通讯作者：
Montealegre-Z，Fernando
中科院分区：
文献类型：
--
作者：
Woodrow，Charlie;Celiker，Emine;Montealegre-Z，Fernando
听觉在动物界已经独立进化了许多次，并在各种昆虫和脊椎动物中突出地用于同种交流和捕食者检测。在昆虫中，知更鸟的耳朵是独一无二的，因为它们进化出了外耳、中耳和内耳的组成部分，在生物物理原理上与哺乳动物的耳朵相似。猫头鹰的耳朵由位于每条前腿的两对鼓膜组成。这些鼓膜在鼓膜表面外部(通常通过耳廓)或内部通过耳道(EC)接收声音。EC的功能是捕捉同种叫声和低频，而耳廓被动地放大高频超声波，包括蝙蝠回声定位。总而言之，这些外耳组件在超过100 kHz的动态范围内提供更高的听力灵敏度。然而，尽管人们对凯蒂德耳朵的生物物理学和功能有了越来越多的了解，但它的确切出现和进化史仍然难以捉摸。在这里，使用微型计算机断层扫描(μCT)扫描，我们恢复了一只保存异常完好的在波罗的海琥珀(∼4400万年[Ma])化石中的蜥蜴的外耳部件和翅膀的几何形状。使用数值和理论模型的翅膀，我们表明，该物种正在通信的峰值频率为31.62(±2.27)千赫，我们证明，耳朵是生物物理调谐到这个信号，并提供听力在更高频率的超声波(>；80千赫)，可能是增强捕食者检测。结果表明，独一无二的猫耳朵的进化出现在始新世，它具有宽频带的超声敏感性和与哺乳动物耳朵相似的生物物理特性。
Hearing has evolved independently many times in the animal kingdom and is prominent in various insects and vertebrates for conspecific communication and predator detection. Among insects, katydid (Orthoptera: Tettigoniidae) ears are unique, as they have evolved outer, middle, and inner ear components, analogous in their biophysical principles to the mammalian ear. The katydid ear consists of two paired tympana located in each foreleg. These tympana receive sound externally on the tympanum surface (usually via pinnae) or internally via an ear canal (EC). The EC functions to capture conspecific calls and low frequencies, while the pinnae passively amplify higher-frequency ultrasounds including bat echolocation. Together, these outer ear components provide enhanced hearing sensitivity across a dynamic range of over 100 kHz. However, despite a growing understanding of the biophysics and function of the katydid ear, its precise emergence and evolutionary history remains elusive. Here, using microcomputed tomography (μCT) scanning, we recovered geometries of the outer ear components and wings of an exceptionally well-preserved katydid fossilized in Baltic amber (∼44 million years [Ma]). Using numerical and theoretical modeling of the wings, we show that this species was communicating at a peak frequency of 31.62 (± 2.27) kHz, and we demonstrate that the ear was biophysically tuned to this signal and to providing hearing at higher-frequency ultrasounds (>80 kHz), likely for enhanced predator detection. The results indicate that the evolution of the unique ear of the katydid, with its broadband ultrasonic sensitivity and analogous biophysical properties to the ears of mammals, emerged in the Eocene.