Visual Olfactory Learning in Mosquitoes

University Of Washington, Seattle WA

Investigators

Abstract

Summary Mosquitoes rely on a combination of sensory cues to locate their hosts, including olfactory, heat, and visual stimuli. Previous studies have shown that olfactory cues play a crucial role in mosquito behavior, but emerging evidence suggests that visual cues are also important, particularly in the final stages of host localization. While significant research has focused on the role of olfaction in mosquito host-seeking behavior, the contribution of vision remains less understood. This proposed research seeks to address this gap by investigating our working hypothesis that bimodal visual-olfactory stimuli elicit more robust behavioral and neural responses from mosquitoes – eventually leading to altered blood-feeding choices. We will test several hypotheses regarding the role of visual and olfactory integration in mosquito behavior and neural processing. Specific Aim 1 investigates the multimodal learning and memory of visual and olfactory stimuli, including host-related cues, in the Yellow Fever Mosquito, Aedes aegypti. This aim will utilize an aversive conditioning paradigm with two testing assays - a two-choice T- maze and a free-flight blood-feeding choice assay, in addition to neurogenetic sensory knockout lines to characterize the interplay between olfactory and visual inputs in mosquito responses. We will determine how aversive learning affects mosquito attraction towards human host odorants and visual wavelengths (1a) and will test the hypothesis that olfaction is the primary driver of learning performance, with visual stimuli enhancing those responses (1b). Specific Aim 2 will investigate the encoding of learned and unlearned host-related visual and olfactory stimuli in the A. aegypti mushroom body (MB), an crucial sensory learning and integration center in the insect brain. Using 2-photon calcium imaging, we will record neural activity in the mushroom body Kenyon cells and dopaminergic neurons in response to olfactory, visual, and bimodal stimuli. This aim will test the hypotheses that KCs exhibit increased activity in response to host-related cues (2a) and that PPL1 dopaminergic neurons will increase their activity following aversive associative conditioning (2b). This comprehensive examination of visual-olfactory sensory encoding in a vector species will significantly advance our understanding of the neural bases of mosquito learning and its implications for host selection. Additionally, the completion of the proposed aims will provide the first evidence of visual-spectral learning in mosquitoes and the first recordings from the mosquito MB. Carrying out these experiments will provide me with training in calcium imaging, neurogenetic techniques, and data analytical approaches. We are confident that the collaborative environment at the University of Washington, along with my mentor's experience in training successful scientists, puts me in an ideal position to achieve these aims and gain the necessary training for my future career.