Female mosquitoes could still detect humans even when their human-scent sensors were disabled. The discovery shows that the insects’ olfactory systems are more complex than previously thought. Now, scientists reveal how mosquitoes are able to smell humans even without antennae.
Mosquitoes hunt for their next meal by detecting human body odor, body heat, and carbon dioxide emissions, which fluctuate from individual to individual.. The research, which was published in the academic journal Cell (read below), suggests that, contrary to animals, which have a single set of neurons that sense each type of odor, mosquitoes may experience scents via a variety of unique pathways.
In order to locate the blood that will nourish their eggs, female mosquitoes use the multitude of odors that humans and other animals generate. The insects’ antennae, which are where they pick up scents, include olfactory neurons that detect and transmit scent information to the brain.
Meg Younger, the study’s primary author, and her colleagues at Boston University in Massachusetts used the gene-editing technique CRISPR to disable clusters of human-odor receptors on the olfactory neurons in the antennae of female mosquitoes (Aedes aegypti).
“We found that there’s a real difference in the way mosquitoes encode the odors that they encounter compared to what we’ve learned from other animals,” Younger is quoted as saying in the Guardian report on the findings.
Younger claims that the researchers assumed mosquitoes would follow the fundamental rule of olfaction, which specifies that each neuron expresses just one kind of receptor.
“Instead, what we’ve seen is that different receptors can respond to different odors in the same neuron,” she added.
This implies that even after missing one or more receptors, mosquitoes can still identify human scents. According to the experts, this backup system might have evolved as a survival strategy.
“The mosquito Aedes aegypti is specialized to bite humans, and it is believed that they evolved to do that because humans are always close to fresh water and mosquitoes lay their eggs in fresh water. We are basically the perfect meal, so the drive to find humans is extremely strong,” Younger explained.
The researchers concluded that by understanding how the mosquito brain interprets human odor, it may be possible to modify biting behavior and halt the spread of diseases like malaria, dengue fever, and yellow fever that are spread by those insects.
“One major strategy for controlling mosquitoes is to attract them to traps to remove them from the biting population. If we could use this knowledge to understand how human odor is represented in the mosquito antennae and brain, we could develop blends that are more attractive to mosquitoes than we are. We could also develop repellants that target those receptors and neurons that detect human odor,” Younger concluded.
Interestingly, fruit flies, or Drosophila melanogaster, exhibit a comparable phenomena, according to recent research by Christopher Potter at the Johns Hopkins School of Medicine in Maryland.
“If one of these types of olfactory receptors is mutated or no longer functioning, there’s this backup system,” Potter is quoted as saying in the New Scientist report. “It’s changing the dogma of what we thought we knew about the olfactory system.”
Read the study below:
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