No matter how well we try to defend ourselves against those damn mosquitoes, they always know where to find us. Researchers have now discovered that mosquitoes perceive human odors in a unique and more complex way than previously thought. Insects always have a backup plan ready to feast on us.
Hive, Guardian, Cynthias
Mosquitoes rely on a combination of body odor, heat and carbon dioxide for their diet. This smell varies from person to person. Animals typically have a specific set of neurons for detecting each type of odor, but mosquitoes have different channels for picking up odors, according to the researchers. For example, scientists were surprised to find that mosquitoes somehow can still smell bitten people after removing an entire family of proteins sensitive to human odors from their genome.
“We’ve seen that different receptors can respond to different odors in the same neuron,” explains Meg Younger, lead author of the study and assistant professor of biology at Boston University. In most animals, only one type of receptor is expressed in each olfactory neuron. “When people lose a single smell receptor, all the neurons expressing that receptor lose the ability to smell that smell,” researcher Leslie Foshall explains. But she and her colleagues have found that this is not the case with mosquitoes.
Mosquitoes are attracted to us by octenol, a pleasant-smelling substance we excrete. But mosquitoes also use amines, another chemical, to track us down. “Surprisingly, the neurons that mosquitoes use to detect octinol and amine receptors are not separate parts,” study researcher Meg Younger concluded. “This allows all human odors to activate the human-detecting part of the mosquito’s brain, even if some receptors are lost.”
This means that a single neuron in a mosquito contains multiple sensory receptors and that the loss of one or more receptors does not affect the mosquito’s ability to pick up human scents. Thus, mosquitoes have a kind of backup system, which, according to the researchers, may have evolved as a survival mechanism. “We are basically the perfect meal, so the desire to find people is very strong,” Younger said.
A better understanding of how the mosquito brain processes human scent will allow us to better intervene in this process and deal with insect bites. “We can develop mixtures that are more attractive to mosquitoes than ourselves,” Younger said. “We can also develop repellents that target those receptors and neurons that detect human odors.”
All of this can be useful in combating the spread of mosquito-borne diseases such as malaria, dengue fever and yellow fever.
See also: More mosquitoes, but fewer wasps this summer
Unlimited free access to Showbytes? And that can!
Log in or create an account and never miss any of the stars.