Collaborative Research: Olfactory learning and neuromodulation in the Aedes aegypti mosquito

University Of Washington, Seattle WA

Investigators

Abstract

Mosquitoes are important vectors of pathogens of disease, accounting for more than a million annual deaths worldwide. We know that mosquitos locate and bite humans by their sensitive sense of smell. However, mosquitoes do not bite everyone equally – some people are bitten more than others. What causes this difference in the mosquito’s biting preference? Remarkably, mosquitoes can learn and remember based on past experiences, particularly the experience of having an animal or person swat at them. The experience of being the target of a swat can modify their odor and biting preferences, but we know remarkably little about how this information is processed in the mosquito brain. This project will use an interdisciplinary approach that combines novel behavioral and electrophysiological techniques from Aedes aegypti mosquitoes to understand how odor learning takes place to modify their biting behaviors. These projects will also incorporate training opportunities for undergraduates, graduate students, and postdoctoral associates with the aim of preparing them for independent scientific careers. High School students in the Upward Bound Program will also participate in the project through summer seminars and lab experiences. In this project, we build on our recent findings that dopamine-mediated learning and modulation in the mosquito’s primary olfactory system, the antennal lobe, is critical for Aedes aegypti mosquito host preferences. Using an interdisciplinary approach, our collaborative team will elucidate the role of dopamine-mediated plasticity in olfactory circuits. We accomplish this with three Objectives: (1) We will test the hypothesis that mosquitoes only learn certain odors, corresponding to the tuning of specific antennal lobe glomeruli. (2) To test that “learnable” odors are encoded by antennal lobe glomeruli that receive dense dopaminergic innervation. And (3) to test the hypothesis that coincident dopamine and odor input cause plasticity of antennal lobe project neurons and allows mosquitoes to learn important olfactory stimuli. We suggest that our proposed experiments may provide a basic framework for understanding the contribution of dopaminergic plasticity in early olfactory circuits. Moreover, olfactory behaviors, including learning, are critical for mosquito preferences and biting of human hosts, and thereby spread diseases that afflict nearly a billion people annually. Therefore, unraveling the neural bases of learning in mosquitoes has important potential for developing new strategies for their control. The project will also introduce students to interdisciplinary research and broadly communicate insect neurobiology's importance to high school students. High School students in the Upward Bound Program will participate in the project through summer seminars and lab experiences. Finally, the project includes training undergraduates, graduate students, and postdoctoral associates and helps prepare them for independent scientific careers. 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.