Localization and frequency resolution in antennal hearing of insects

Insects rely on their hearing in order to communicate, identify and locate potential mates, and avoid predators. Due to their small sizes, many insect species are not able to use the interaural time and intensity differences employed by vertebrates for the localization of sound, but have instead evolved other mechanisms to perform this task. One such mechanism is the antenna, which provides directionally sensitive acoustic information. In contrast to tympanic ears, which detect scalar pressure fields, antennal ears detect the vector-valued velocity fields of sound. We argue that this detection scheme at small length scales, combined with the dipolelike radiation of sound emitted from flying insects, results in short ranges of detection. These short ranges imply that the acoustic signals transmitted between two insects flying past each other will be brief and rapidly changing with time, presenting a challenge in extracting precise frequency information. However, this frequency information has been shown to be essential for insects to identify and locate potential mates. In the current work, we propose potential mechanisms that insects may employ in order to extract precise frequency and directional information from these transient signals, thereby circumventing the apparent limitations.