Ellie Teng ‘21

Getting a mosquito bite is common during warmer weather, however in certain places, it could be deadly, as mosquitoes are major transmitters of disease. Bloodborne pathogens are easily transferred between humans. To determine how a female mosquito identifies, tracks and prey on a potential host, a group of scientists from the University of Washington studied the two sensory systems in mosquitoes: the visual and olfactory senses. 

Mosquitoes can detect carbon dioxide, which is a signal that they are close to a meal. Results from this study indicated that CO2 detection activates an attraction to visual features in the female mosquito. This means that their sense of smell is stronger than their vision, and that they will only look towards the object in their visual field if they can smell it first. Humans and animals exhale CO2, which is detected by mosquitoes as far as 100 feet away. A study of their brains confirmed this, as mosquitoes who smelled CO2 first and then showed an image or visual stimuli had a 23% increase in the lobula of their optic lobe, indicating increased neuronal activity. When the experiment was flipped and the mosquitoes were exposed to CO2 after the visual stimulus, no response was recorded. 

Since mosquitoes have poor eyesight, only seeing up to 15 to 20 feet ahead of them, they rely on their olfactory system to trigger and control vision. Previous studies have also noted that mosquitoes respond to thermal stimuli, though more studies are required to understand how it relates to their olfactory and visual senses. This experiment and related studies will likely aid in efforts to control mosquito populations and control the spread of disease.

References:

1. C. Vinauger, et al., Visual-olfactory integration in the human disease vector mosquito aedes aegypti. Current Biology (2019). Doi: 10.1016/j.cub.2019.06.043
2. Image retrieved from: https://www.newsweek.com/china-scientists-released-millions-infected-sterilized-mosquitoes-wild-wipe-out-1449709