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

点击翻译按钮获取中文摘要

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.