Mosquitoes are attracted to humans because they see red
- Mosquitoes are infamous in transmitting pathogenic and parasitic diseases.
- Mosquito-borne diseases include malaria, dengue, Zika virus, and West Nile virus.
- In 2020, more than 600,000 people died of malaria mostly young children in sub-Saharan Africa.
- Mosquitoes use their visuals to track odor, seek hosts, and find mates.
- The food resource color can be dominated by long wavelengths of the visible light spectrum which is necessary for recognizing and localizing objects.
- In humans, the long wavelengths of the visible light spectrum range from red to green.
- There is a lack of knowledge regarding the color that attract mosquitoes or how odor influences their visual search behavior.
- Researchers used real-time 3D tracking system and wind tunnel to control the olfactory and visual environment of the mosquitoes.
- Researchers quantified and analyzed the behavior of more than 1.3 million mosquito trajectories.
- They found that carbon dioxide triggers a strong attraction to specific colors including those in humans seen as red, orange, and cyan.
- Sensitivity to red and orange is associated with mosquitoes’ attraction to the human skin.
- Human skin is dominated by the wavelengths of red and orange.
- Additionally, researchers mutated the opsin or carbon dioxide detection in mosquitoes and filtered the red and orange bands from the skin color spectrum and found that the mosquitoes’ attraction was eliminated.
- Opsin is trans-membrane protein that bind to chemicals that react upon light exposure.
- Opsin plays a major role in vision, circadian rhythms, phototaxis, and other light-controlled responses of organisms.
- The results highlight the importance of odor in color preferences of the mosquitoes and that the mosquito visual system may be a target to combat their attraction to humans.
Alonso San Alberto, D., Rusch, C., Zhan, Y. et al. The olfactory gating of visual preferences to human skin and visible spectra in mosquitoes. Nat Commun 13, 555 (2022). https://doi.org/10.1038/s41467-022-28195-x