As the warmer months approach, the number of mosquito bites you’re getting is probably starting to rise. Those pesky insects use their mouths to penetrate our skin and suck up our blood, leaving an itchy, swollen bite in its place.
For some areas in the world, a bite from one of these animals leaves behind more than an irritation. Mosquitoes can carry numerous diseases including Malaria, Dengue Fever, Zika Virus, and Chagas Disease. Clearly, it’s in all of our best interest to get them to stay as far away from us as possible.
Insect repellents tend to be the best option when trying to protect our skin throughout the day. Still, these aren’t completely protective and people can still end up covered head to toe in a series of infuriating bites.
Surprise findings from John Hopkins Medicine have figured out why this is the case. “When experiments don’t go as predicted, there’s often something new to be discovered,” says Christopher Potter, who worked on the study. “Mosquitoes are so much trickier than we thought.”
How do mosquitoes smell?
It was presumed that mosquitoes sense odor using their olfactory system, the system animals use to perceive smell, the same way fruit flies do. It The assumption was that their odor receptor picks up the scent, decides whether it’s a positive or negative one, and directs the insect’s behavior towards or away from the stimulus.
These findings showed mosquitos are actually more complex than this and can unexpectedly flick their smell receptors on and off like a light switch to ignore certain scents. The group published their findings recently in Cell Reports.
The experiments were carried out on the female Anopheles mosquitoes, the species that transmit malaria to humans. The group was actually looking at a way to manipulate an odor receptor called AgOR2 which responds to animal odorants that humans carry. Through genetic modification the group was hoping they could pull some tricks to improve the power of insect repellents.
However, the modified mosquitoes ended up ignoring the repellent, the opposite result of what was expected, leaving the group with many questions. Using a type of RNA sequencing, which measures the amount of activity of the AgOR2 gene, they uncovered the interesting trick these tiny creatures can pull.
The group hopes this olfactory flexibility can be used in the future to advance methods of mosquito repellents, tricking their olfactory systems into no longer preferring the smell of humans.
Source study: Cell Reports – Odorant-receptor-mediated regulation of chemosensory gene expression in the malaria mosquito Anopheles gambiae