A new study from Virginia Tech reveals mosquitoes remember a host’s smell. However, these bloodsuckers will steer clear of a host associated with a life-threatening experience.
Mosquitoes Have Preferences
Some people are more likely to get bitten by mosquitoes, and researchers agree with this common belief. According to the study published in Current Biology on Jan. 25, mosquitoes remember a host’s smell thanks to dopamine. Using their memories, mosquitoes develop a preference for a particular set of scents. Hence, some people are more susceptible to mosquito bites.
How mosquitoes develop preferences is not the only significant finding in the study.
As reported in Science Daily, Chloe Lahondere, a research assistant professor in Virginia Tech’s Department of Biochemistry, and Clement Vinauger, an assistant professor of biochemistry in College of Agriculture and Life Sciences, found that mosquitoes are capable of aversive learning. The researchers used female Aedes aegypti mosquitoes to prove that bloodsuckers associate smell with unpleasant experiences.
Aedes aegypti mosquitoes transmit diseases like dengue, yellow fever, Zika virus, and chikungunya.
Aversive Learning Experiment
The mosquitoes were bathed in a scent similar to their preferred human host while exposed to vibrations with the same intensity as a swat. The bloodsucking insects were confined in this environment for 20 minutes.
After 24 hours, the mosquitoes were exposed to the same scent. The researchers observed the insects avoided the odor they associate with the life-threatening experience. Instead of being an attractive scent, the smell warned them of danger. The effect is as powerful as wearing an insect repellent to keep mosquitoes away.
— Current Biology (@CurrentBiology) January 25, 2018
Dopamine is the key to linking behavior with experiences. To test if dopamine is responsible for this mosquito behavior, the researchers disabled dopamine channels in some bloodsuckers. For this test group, mosquitoes were not able to interpret the scent as a sign of danger.
Jeff Riffell, a neuroecologist at the University of Washington, explains that this learning ability makes mosquitoes flexible.
“It means they can learn associations about who is more defensive and who isn’t, and if we can prevent that, they’ll never learn and can be swatted away way more effectively.”
As noted in National Geographic, the mosquitoes used in the experiment may be the only species to exhibit this behavior. Mosquitoes responsible for transmitting West Nile prefer bird hosts. If there are no birds in the vicinity, they switch to human hosts. Riffell reveals that these mosquitoes didn’t show the ability to avoid danger based on learned behavior.