Acoustic designs of orthopteran insects

蟋蟀和蟋蟀通过摩擦它们的前翅发出声音。歌声是雄性用来吸引雌性交配的，在某些物种中也用于雄性竞争。它们前腿上的鼓膜由身体其他部位的内部气管支撑。与人类相比，这些昆虫的信号系统，无论是发生器还是接收器，都是小型化的。我们正试图了解这些微小而短小的结构是如何发挥作用来传播如此长的声波波长的。我们对发电机的研究是问翅膀下面体腔的形状和体积如何影响广播声音的响度。一些物种有突出的声音反射身体区域，而另一些则完全将它们的发声前翅封闭在一个腔室中：我们正在测试这些身体改造如何影响昆虫周围产生的声场。相对于波长来说，蟋蟀是如此的小，以至于它们无法通过身体的“声音阴影”来确定远处呼叫者的位置：它们的身体不会产生声音强度的左右差异。相反，它们通过内部空气管将声音传导到身体各处，因此声波在不同的时间到达每个耳膜的前部和后部，经过不同的路径长度。当蟋蟀转弯时，路径相对于彼此改变，并在耳膜处引起声音干扰，从而给出可用的双耳定位线索。我们正在比较许多不同种类的蟋蟀耳朵的内部气管排列。最后，这项研究是一项研究，是否高性能的声学信号的难度，如音乐会钢琴家所需的技能水平，可以诚实的评估的基础上，一个更好的伴侣，由女性Katydids选择唱歌的男性。我们改变男性的信号质量，观察女性的偏好。这项工作的共同主题是深入了解声音是如何处理的缩小动物器官。人们希望能发现一些适应性的东西，从而改进类似的小型设备的设计，比如用来对付人类耳聋的助听器。

Crickets and katydids make sounds by rubbing their forewings together. Songs are generated by males to attract females for mating and in some species also used in male rivalry. Eardrums on their forelegs are backed by internal air tubes opening elsewhere on the body. Compared to humans, the signal system of these insects, both generators and receivers, is minaturized. We are trying to understand how such tiny and short structures function to broadcast sound wavelengths that are so long. Our research into generators asks how the shape and volume of body cavities below the wings affect the loudness of the broadcast sound. Some species have projecting sound-reflective body regions, while others completely enclose their sound-making forewings in a chamber: we are testing how these body modifications affect the sound field created around the insect. Being so small relative to wavelength, crickets are unable to fix the position of a distant caller by body 'sound shadow': no side-to-side differences in sound intensity are created by their body. Instead they conduct the sound across their body via internal air tubes and so sound waves reach the front and back of each eardrum at different times, after travelling different path lengths. As the cricket turns, the paths change relative to each other and cause sound interference at the eardrum giving usable binaural localization cues. We are comparing the internal air-tube arangements of the ears of many different cricket species. Finally, this research is a study of whether the difficulty of high-performance acoustic signalling, like the skill level needed by a concert pianist, can be the basis of honest assessment of a better mate by female katydids choosing among singing males. We change a male's signal quality and observe female preferences. The common theme of this work is gaining insight into how sound is processed by minaturized animal organs. One hopes to discover adaptations that will suggest improved design of similarly small devices such as the hearing aids used to counter human deafness.