The taste system plays a crucial role in controlling various insect behaviors. Still, more needs to be understood about how tastants (taste stimuli) are encoded in mosquitoes and how they influence essential behaviors.
Yale researchers have discovered how taste influences mosquitoes’ biting behavior. This finding could lead to new strategies for preventing mosquito bites and potentially stopping the spread of diseases they carry.
Recent research has uncovered how different tastes are encoded by neurons in mosquitoes, influencing behaviors like biting, feeding, and egg-laying. The study identifies specific compounds in human sweat that can increase mosquito biting and bitter compounds that suppress feeding and egg-laying. These findings offer new insights into why some people are more attracted to mosquitoes than others.
Focusing on the Asian tiger mosquito, which has expanded globally and is now found on six continents, the study highlights the species’ role in spreading diseases like dengue and chikungunya. As this mosquito outcompetes other species, it poses an increasing threat to public health in the future.
To explore the Asian tiger mosquito’s taste abilities, researchers tested 46 different taste compounds, including sugars, salts, bitter compounds, and amino acids. They observed how neurons in the mosquito’s taste organ responded to each compound. The results showed that while some compounds, like sugars, activated many neurons, others surprisingly inhibited neuronal activity.
Senior author John Carlson, the Eugene Higgins Professor of Molecular, Cellular, and Developmental Biology in Yale’s Faculty of Arts and Sciences, said, “We’ve done a lot of research on taste in the fruit fly, and we haven’t seen this kind of widespread inhibition before in flies. These two different responses — excitation and inhibition — give mosquitoes an expanded ability to encode taste, meaning they can likely differentiate various tastes.”
The researchers also examined how different taste compounds influenced mosquitoes’ biting, feeding, and egg-laying behaviors. They found that certain tastes either promoted or suppressed specific behaviors. For example, bitter compounds reduced feeding but didn’t affect egg-laying. Additionally, while salt and amino acids commonly found in human sweat had no impact on biting individually, they increased biting when combined.
This combination of salt and amino acids in human sweat likely explains why mosquitoes are drawn to human skin. The researchers suggest mosquitoes can detect this unique combination, recognizing it as a favorable spot to bite. Furthermore, when the researchers presented mosquitoes with different human sweat samples, they found that the mosquitoes showed a clear preference for some samples over others, indicating that certain sweat compositions may be more attractive to mosquitoes.
Carlson said, “We think this could be part of why some of us get bitten by mosquitoes more than others. Some people may just taste better to mosquitoes.”
Researchers noted, “Together, the findings help describe how mosquitoes that have landed decide whether to bite or fly away. That information may help identify compounds that sway mosquitoes to leave rather than bite.”
Journal Reference:
- Baik, L.S., Talross, G.J.S., Gray, S. et al. Mosquito taste responses to human and floral cues guide biting and feeding. Nature 635, 639–646 (2024). DOI: 10.1038/s41586-024-08047-y