Eavesdropping behavior and sound localization: Lessons from a small auditory specialist

能够定位声源对于动物对环境中的刺激做出反应是至关重要的。事实上，识别声音来源的位置通常与成功寻找配偶、获取食物和躲避捕食者有关。然而，确定声音在哪里产生并不是一项简单的任务，也不是完全理解的。例如，对于用触角听的动物来说，尚不清楚它们如何识别声音的位置。此外，由于物理和生物原因，声源本地化的挑战对小型生物来说尤其困难。鉴于许多使用触角听的生物都很小，因此它们如何实现准确的声音定位尤其令人费解。通过研究蚊子窃听青蛙的叫声来攻击它们，研究人员将检查用触角倾听的小动物的行为和潜在的神经生理机制。这项工作将揭示与高度敏感的小耳朵相关的感觉策略，这些小耳朵允许蚊子利用青蛙的交流系统。这些发现将增加我们对小动物如何准确地确定声音是在哪里发出的理解，这对开发小型人工听力传感器具有重要意义。此外，作为该项目的一部分，一个由不同的年轻科学家组成的团队将接受声学、动物行为和神经生理学方面的尖端技术培训。在这项提案中，研究人员将通过调查一种叮咬青蛙的蚊子(Uranotaenia Lowii)来解决小型生物使用鞭毛耳朵进行声音定位的挑战。在这个物种中，雌性是物种间的窃听者，专门利用青蛙的叫声来获取血液食物来支持产卵。该物种提供了一个高度易处理的系统，其中可以集成多个层次的分析(行为学、声学、生物力学和神经生理学)，以全面调查窃听行为背景下的声音定位。我们将研究声音本地化的三个基本方面。首先，将调查叮咬青蛙的蚊子对它们所利用的叫声的自然变化的趋声行为。将确定蚊子接近青蛙叫声时遵循的定位精度和行为规则。在第二部分中，蚊子定位声音的能力将与触角的生物力学反应有关。将研究天线单独和成对系统对不同方位广播声音的响应。最后，在第三部分中，将确定允许编码关于声源位置的信息的神经生理机制。第二部分和第三部分的结果将提供对在野外观察到的行为的近似解释，并在第一部分中仔细描述。最终，这项工作将确定声音定位的关键适应，从而深入了解叮咬青蛙的蚊子窃听的感觉生态。总体而言，这项研究将增加我们对鞭毛耳使用机制的理解，为微小生物如何克服健全的本地化挑战提供见解。这一奖项反映了NSF的法定使命，并通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。

Being able to localize sound sources is critical for animals to respond to stimuli in their environment. Indeed, identifying the location from where sound originates is often relevant for successfully finding mates, acquiring food and escaping predators. Determining where a sound is produced, however, is no simple task or fully understood. For animals that hear with their antennae, for instance, it is unclear how they can identify the location of a sound. In addition, due to physical and biological reasons, the challenge of localizing a sound source is particularly difficult for small organisms. Given that many organisms that use their antennae to hear are small, it is thus particularly puzzling how they can achieve accurate sound localization. By investigating mosquitos that eavesdrop on the calls of frogs to attack them, the researchers will examine the behavior and underlying neurophysiological mechanisms of small animals that hear with their antennae. This work will reveal the sensory strategies associated with highly sensitive, small ears that allow mosquitos to exploit the communication system of frogs. These findings will increase our understanding of how small animals can pinpoint where a sound is produced which has implications for developing small, artificial hearing sensors. In addition, as part of this project, a team of diverse, young scientists will be trained in cutting-edge techniques in acoustics, animal behavior and neurophysiology. A variety of outreach activities for the community in general will be performed to generate interest and enthusiasm about animal behavior and, more generally, the nature of science.In this proposal, the researchers will address the challenge of sound localization by small organisms using flagellar ears by investigating a frog-biting mosquito (Uranotaenia lowii). In this species, females are interspecific eavesdroppers specialized on using frog calls to obtain blood meals to support egg production. This species provides a highly tractable system in which multiple levels of analysis (ethological, acoustical, biomechanical, and neurophysiological) can be integrated to comprehensively investigate sound localization in the context of eavesdropping behavior. Three essential aspects of sound localization will be examined. First, the phonotaxis behavior of frog-biting mosquitoes to natural variation in the calls they exploit will be investigated. The localization accuracy and behavioral rules followed by mosquitoes approaching frog calls will be determined. In part 2, the ability of mosquitoes to localize sound will be related to the biomechanical response of the antennae. The movement of the antenna individually, and as a paired system, in response to sounds broadcast at different azimuth will be examined. Finally, in part 3, the neurophysiological mechanism allowing encoding information about sound source location will be determined. The results of parts 2 and 3 will provide proximate explanations of behaviors observed in the wild and carefully characterized in part 1. Ultimately, this work will determine critical adaptations for sound localization providing insights about the sensory ecology of eavesdropping in frog-biting mosquitoes. Overall, this research will increase our understanding of the mechanisms underlying the use of flagellar ears providing insights about how sound localization challenges are overcame by tiny organisms.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.