Baker Andrew Alexander, Jonsson Thorin, Aldridge Sarah, Montealegre-Z Fernando
University of Lincoln, School of Life Sciences, Joseph Banks Laboratories, United Kingdom.
University of Lincoln, School of Life Sciences, Joseph Banks Laboratories, United Kingdom.
J Insect Physiol. 2019 Apr;114:100-108. doi: 10.1016/j.jinsphys.2019.03.005. Epub 2019 Mar 18.
Male Katydids (Orthoptera: Tettigoniidae) rub together their specialised forewings to produce sound, a process known as stridulation. During wing closure, a lobe on the anal margin of the right forewing (a scraper), engages with a tooth-covered file on the left forewing. The movement of the scraper across the file produces vibrations which are amplified by a large wing cell adjacent to the scraper, the mirror. Katydids are known to stridulate with either sustained or interrupted sweeps of the file, generating resonant pure-tone (narrowband frequency) or non-resonant (broadband frequency) calls. However, some species can conserve some purity in their calls despite incorporating discrete pulses and silent intervals. This mechanism is exhibited by many Pseudophyllinae, such as Nastonotus spp., Cocconotus spp., Triencentrus spp. and Eubliastes spp. This study aims to measure and quantify the mechanics of wing stridulation in Nastonotus foreli, a Neotropical katydid that can produce, relatively narrowband calls at ≈20 kHz. It was predicted that this species will use a stridulatory mechanism involving elastic energy whereby the scraper bends and flicks along the file in periodic bursts. The calling behaviour and wing mechanics of seven males were studied using a combination of technologies (e.g. micro-scanning laser Doppler vibrometry, advanced microscopy, ultrasound-sensitive equipment and optical motion detectors) to quantify wing mechanics and structure. Analysis of recordings revealed no clear relationship between wing velocity and carrier frequency, and a pronounced distinction between wing velocity and scraper velocity during wing closure, suggesting that the scraper experiences considerable deformation. This is characteristic of the elastic scraper mechanism of stridulation. Curiously, N. foreli might have evolved to employ elastic energy to double the duration of the call, despite possessing muscles that can reach velocities high enough to produce the same frequency without the help of elastic energy.
雄性螽斯（直翅目：螽斯科）摩擦其特化的前翅以产生声音，这一过程称为摩擦发音。在翅膀闭合时，右前翅臀缘上的一个叶状结构（一个刮板）与左前翅上覆盖着齿的锉状结构相啮合。刮板在锉状结构上的移动产生振动，这些振动会被与刮板相邻的一个大的翅室——镜膜放大。已知螽斯通过持续或间断地扫过锉状结构来进行摩擦发音，产生共振纯音（窄带频率）或非共振（宽带频率）叫声。然而，一些物种尽管包含离散脉冲和静音间隔，但仍能在叫声中保持一定的纯净度。许多伪叶螽亚科的物种都表现出这种机制，如纳氏螽斯属、椰螽斯属、三齿螽斯属和优氏螽斯属。本研究旨在测量和量化前利纳氏螽斯翅膀摩擦发音的机制，前利纳氏螽斯是一种新热带螽斯，能产生频率约为20千赫的相对窄带叫声。据预测，该物种将采用一种涉及弹性能量的摩擦发音机制，即刮板会周期性地沿着锉状结构弯曲和弹动。使用多种技术（如显微扫描激光多普勒测振仪、先进显微镜、超声敏感设备和光学运动探测器）对7只雄性的鸣叫行为和翅膀力学进行了研究，以量化翅膀力学和结构。对录音的分析表明，翅膀速度与载波频率之间没有明显关系，并且在翅膀闭合期间翅膀速度和刮板速度之间存在明显差异，这表明刮板经历了相当大的变形。这是摩擦发音的弹性刮板机制的特征。奇怪的是，尽管前利纳氏螽斯拥有能够达到足够高速度以在没有弹性能量帮助的情况下产生相同频率的肌肉，但它可能已经进化到利用弹性能量来使叫声持续时间翻倍。
