# The olfactory basis of locating nectar sugar sources in Aedes aegypti mosquitoes

> **NIH NIH R01** · UNIVERSITY OF WASHINGTON · 2024 · $84,979

## Abstract

The objective of the proposed R01 project is to build on our recent findings that attractive odors from sources of
nectar activate conserved olfactory channels in mosquitoes, and the odorant ratios within the scent, along with
the inhibition in the antennal lobe (AL), are critical for Aedes aegypti behavior. 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 fruit odor can strongly impact its attractiveness. We still have not identified the
odor constituents and ratios that are attractive in the nectar odors – enabling the development of synthetic lures
–, nor how this information is detected and processed by the mosquito's olfactory system.
 Nectar-feeding by female mosquitoes increases their life-span and decreases the gonotrophic cycle, thereby
increasing their vectorial capacity, and for adult males, it is the only source of nutrients. 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. Now in this application, we propose to 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. Aim 1 will allow us to identify attractive odorants in the
scents of diverse plant nectar sources and use heterologous expression systems to de-orphan the cognate
odorant receptors (Ors). We also take advantage of the Q-system for genetically characterizing three Ors (Or15,
Or49, and Or2) that are essential for representing the proper ratios in nectar odors. In Aim 2, we leverage our
existing and new GCaMP expression lines to examine how the ratios of these key odorants are processed in the
AL, and how GABAergic inhibition shapes these responses. In Aim 3, we will use our identified odor lures, and
artificial lures that vary in their natural ratios of key odorants, to determine their efficacy in bait-and-kill systems.
Together, these experiments will test the working hypothesis that nectar odors and their specific odorant ratios
activate conserved olfactory channels to be processed similarly by AL circuits to mediate feeding behaviors.
 While there has been an extensive study of mosquito attraction to blood hosts, we know comparatively less
about nectar feeding. Our experiments will identify new odors that can be immediately deployed as attractant
lures. Additionally, GABAergic systems are involved in diverse physiological processes in insect vectors,
including olfaction, immune response, and arbovirus replication, as well as being potent targets for insecticides.
Generating mutants that target the mosquito's olfactory responses or GABAergic pathways could provide
additional...

## Key facts

- **NIH application ID:** 10907916
- **Project number:** 3R01AI148300-04S1
- **Recipient organization:** UNIVERSITY OF WASHINGTON
- **Principal Investigator:** Omar Sultan Akbari
- **Activity code:** R01 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2024
- **Award amount:** $84,979
- **Award type:** 3
- **Project period:** 2021-03-05 → 2026-02-28

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/10907916

## Citation

> US National Institutes of Health, RePORTER application 10907916, The olfactory basis of locating nectar sugar sources in Aedes aegypti mosquitoes (3R01AI148300-04S1). Retrieved via AI Analytics 2026-05-25 from https://api.ai-analytics.org/grant/nih/10907916. Licensed CC0.

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