Chemical ecology and olfactory basis of mosquito attraction to sources of nectar

Feeding on fruits and flowers is a vital behavior for mosquitoes, and mosquito attraction to these sources of nectar is mediated by the ratio of key odorants in the bouquet.  Bait-and-kill traps that use fruit syrups have effectively controlled local mosquito populations, but variation in the odor can strongly impact their attractiveness.  The identity and proportions of odor constituents attractive in the nectar odors – enabling the development of synthetic lures – remain unknown. It is also unclear how this information is processed by the mosquito's olfactory system. Our recent work allowed us to identify the odor constituents that mediate nectar-feeding behaviors in Ae. aegypti and understand how the odor is processed in the brain.  To fill these gaps, we use a combination of behavioral assays, chemical methods combined with calcium imaging in tethered flying mosquitoes, and genetic approaches to study the olfactory basis of nectar-seeking behaviors.  We have identified attractive odorants in the scents of diverse nectar sources.  Our existing and new GCaMP expression lines are leveraged to examine how the ratios of these key odorants are processed in the mosquito's brain, and how the proportions of compounds in the odor shape these responses.  Finally, we will discuss using odor lures that vary in their natural ratios of key odorants, to determine their efficacy in mosquito attraction. Sugar feeding plays an essential role in the vectorial capacity of mosquitoes and the spread of disease pathogens. Therefore, unraveling the bases of nectar feeding will enable new tools for their control.