Previously, it was known that people whose skin contained more lactic acid were more attracted to small vampires. Flying insects also rate other chemicals for their attractiveness, bacteria levels and even body odor.
But in the new study publishedresearchers have discovered how mosquitoes have evolved precise targeting mechanisms to distinguish between human and animal odors.
Carolyn McBride, assistant professor of ecology and evolutionary biology and neuroscience, and quoted in the report explained the basis of the study: “We dive into the mosquito’s brain and ask: ‘ What can you smell? What turns on your brain? What makes your neurons work? And how does your brain react differently depending on whether you smell a human scent or an animal scent?« .
What did the scientists do?
The group of scientists created genetically modified Aedes aegypti mosquitoes, vectors of Zika virus, dengue virus, yellow fever virus and chikungunya virus, using CRISPR-Cas9.
These transgenic insects had brains that lit up when active, allowing experts to obtain high-resolution images of the brains. Later fed these mosquitoes human and animal flavored air through a wind tunnel to determine what caught the insect’s attention.
The study clarifies that human odor is made up of many different compounds, and that these same compounds are also present in most mammalian odors, although in different proportions, making it difficult to determine the exact proportions of the compounds. attractive.
To that end, the new research used the scent of 16 humans, two rats, two guinea pigs, two quails, one sheep and four dogs to stimulate the mosquito’s appetite.
Jessica Zung, author of the study, adds: For the human samples, we had a lot of great volunteers. We asked them not to bathe for a few days, then they stripped and lay in a teflon bag.« .
« Why did the human volunteers have to be naked? The other fibers of the garment could falsify the data because they have their own smell.« .
With the collected odors, the researchers devised an ingenious system to infuse genetically modified mosquitoes with odors into the brain area of the imaging device.
The study determined that mosquitoes detect two chemicals, decanal and undecanal, which are enriched by human odor and likely come from lipids in human skin rather than sweat.