How do mosquitoes know they are stinging a human or an animal? Is it the sweat that we release a way to identify ourselves? A group of researchers from the Tropical Genetics Laboratory of Miami has discovered an olfactory receptor in their antennae that could help them know if we are human enough to "bite".
To understand it, we are going to think about some particular mosquitoes, in Aedes aegypti, which are dangerous transmitters of Zika and Dengue. The females find in the blood of the vertebrates the necessary nutrients to lay their eggs. They are attracted to the carbon dioxide emitted by humans when they breathe and by the lactic acid in their sweat. So they use the sense of smell to find their new prey. But how do they do it? Thanks to an olfactory receiver, which is found in the antennae of mosquitoes and that helps them to identify us from animals.
Since the 60s it is known that mosquitoes were guided by the lactic acid of sweat to find us, but now they have managed to identify the gene that makes this union effective. If they managed to modify it, they could find a way to prevent the mosquitoes of the future from biting humans. This is explained to Sinc, the neurobiologist Matthew DeGennaro, leader of the work that has been published in the journal Current Biology: "When this gene is eliminated in the laboratory, the insect loses its ability to respond to volatile acids and, therefore, approximately 50% of its attraction to humans. "
To achieve this, they eliminated the olfactory receiver from the mosquitoes through a genetic editing system CRISPR-Cas9. Then they released wild mosquitoes and others with the modified gene near the investigator's arm and found that the first ones were resting on him, while the second ones did not feel any attraction for him during the 4 minutes that the experiment lasted.
Researchers believe that thanks to these results it will be possible to create much more effective repellents: "Odors that mask the pathway which could improve the effectiveness of current repellents, so our discovery would help prevent people from being the main prey of these insects, "says DeGennaro.