"Once mosquitoes learned odors in an aversive manner, those odors caused aversive responses on the same order as responses to DEET, which is one of the most effective mosquito repellents", commented senior author and UW professor of biology Jeff Riffell. They usually went for the scent that wasn't associated with the swatting sensation. Using gene editing technology, the researchers also discovered that dopamine was associated with the learning process that caused the insects to avoid unsafe situations. This study, produced by researchers at Virginia Tech, looked into what prompted that switch, and it found out not only why mosquitoes targeted certain people but also that they had an wonderful ability to anticipate swats.
Mosquitoes can learn to associate an odor with a mechanical shock similar to a swat-and then avoid that scent in the future-new research suggests. Later, mosquitoes flew upwind and had to choose between the smell of a tasty human - which they previously preferred - and a control odor.
The visual "arena" in which researchers tested the responses of mosquitoes to different odors.
Further analysis revealed that dopamine, a chemical messenger that carries signals between brain cells, also plays an essential role in mosquito learning. Hosts who swat at mosquitoes or perform other defensive behaviors may be abandoned, no matter how sweet.
Researchers already knew that mosquitoes don't decide whom to bite at random. While the insects have certain preferences for some people over others, they also swap hosts seasonally.
A mosquito flies on the end of a tether during an experiment to study responses to a swat-like shock. The critters that didn't have dopamine receptors by genetic modification couldn't learn to avoid smells associated with swatting.
"We show that olfactory learning may contribute to Aedes aegypti mosquito biting preferences and host shifts". Those experiments showed that without dopamine, those neurons were less likely to fire. However, they did not learn to veer away from chickens, and researchers believe it's because the insects learned to avoid specific scents that are in mammals, but apparently not in birds.
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It also could help prevent the transmission of certain infectious diseases, Lahondere said to USA Today.
The study, published in Current Biology, was intricately created to gauge the learning abilities of the mosquito species, Aedes aegypti.
Dopamine staining in the brain of an Aedes aegypti mosquito.
"By understanding how mosquitoes are making decisions on whom to bite, and how learning influences those behaviors, we can better understand the genes and neuronal bases of the behaviors", says Riffell.
"Now that we have a better understanding of what the mosquitoes are capable of", she said, "we need to investigate how to apply this knowledge to refine our control strategies and fight more efficiently against the disease that these mosquitoes transmit".
Authors of the paper include Clément Vinauger, Chloé Lahondère, Gabriella H. Wolff, Lauren T. Locke, Jessica E. Liaw, Jay Z. Parrish, Omar S. Akbari, Michael H. Dickinson, and Jeffrey A. Riffell.