Researchers at Johns Hopkins Medicine discovered specialized receptors on mosquito nerve cells that can fine-tune their ability to detect appealing odors in human skin, potentially explaining why mosquitoes are more attracted to certain people. These receptors, known as ionotropic receptors, are activated by acids and amines, which are found on human skin. Understanding the molecular biology of mosquito odor-sensing is critical for developing new methods of avoiding mosquito bites and the diseases they can cause, such as malaria, dengue fever, and West Nile virus.

Mosquitoes detect odors primarily with their antennae, but they also use a variety of senses to locate hosts. Most ionotropic receptors were found in the distal part of the antennae, farthest from the head, while the proximal part had an unexpected amount of ionotropic receptors. This complication implies that mosquito antennae are more complex than previously thought.

To respond to odors, ionotropic receptors collaborate with “partner” receptors. The researchers identified some receptor pairings that predicted whether an ionotropic receptor would respond to acids or amines. The ability of odors to activate and inhibit ionotropic receptor-expressing neurons may allow mosquitos to expand the range of responses ionotropic receptors can play in odor detection and driving behaviors.

Female mosquitos bite humans, but some research suggests that males are also attracted to human odors. Future research will concentrate on identifying the specific ionotropic receptors that attract mosquitos to human odors. Mosquito control efforts with nets and pesticides have helped reduce the toll of mosquito-borne diseases, but developing better repellents to counteract odorant attraction remains a priority.

This research has been published in Cell Reports.

References

• Johns Hopkins Medicine Newsroom. (2023, February 21). Researchers Map Mosquito Cells That May Help the Insects Choose Tastiest Humans. Johns Hopkins Medicine Newsroom; Johns Hopkins Medicine. https://www.hopkinsmedicine.org/news/newsroom/news-releases/researchers-map-mosquito-cells-that-may-help-the-insects-choose-tastiest-humans
• Raji, J. I., Konopka, J. K., & Potter, C. J. (2023). A spatial map of antennal-expressed ionotropic receptors in the malaria mosquito. Cell Reports, 42(2), 112101. https://doi.org/10.1016/j.celrep.2023.112101