UC Santa Barbara

The five classical senses including vision, taste, smell, hearing, and touch, are being used by us humans and all the living organisms in the world constantly. These senses help us perceive signals from the environment around us like colors, flavors, aromas, sounds and textures. Most importantly, these senses are essential for us to survive. In this dissertation, we will describe the mechanisms underlying behaviors like circadian rhythms, taste, and touch in Drosophila and Aedes aegypti. We will describe the discovery of the importance of a minor group of rhodopsins in regulating sleep chronotype in Drosophila. Essentially, we identified that a small subset of Drosophila photoreceptor cells that express rhodopsin 3 (rh3) is required for regulating sleep chronotype. rh3 mutants displayed an evening chronotype with delays in sleep, activity, feeding, and core clock gene expression. The rh3 mutants possessed a longer internal periodicity than control flies. And importantly, we found that the evening chronotype in rh3 mutants could be rescued by the alignment of external and internal periodicities or restricted time of feeding. In this study, we also explored the taste preferences of mosquitoes for different carboxylic acids as acid taste is important for their host seeking behavior and nectar feeding behavior. We found that mosquitoes are aversive to low pH food and have specific preferences for the carboxylic bone of lactic acid. Additionally, we also investigated the function of a mechanosensor, tmem63, in texture detection during blood and nectar feeding behavior of mosquitoes. We verified its expression in the proboscis of mosquitoes and also observed that this receptor was involved in the detection of food texture. This dissertation combined research from both Drosophila and Aedes aegypti as they share homolog genes and similar sensory organs that are important for specific behaviors and enable them to survive and thrive in their habitats. Studies in Drosophila advanced and accelerated our research in Aedes aegypti, which is the most dangerous animal in the world. Through this research, we hope to provide a better understanding of their circadian rhythm, taste perception and mechanosensation, which can shed light on finding solutions for sleep disorders treatments and suppressing the spreading of infectious diseases by mosquitoes.