A study at Virginia Tech has found that mosquitoes can rapidly learn and remember the smells of hosts. Delicious-smelling individuals are usually the preferred targets, but swatting at them or performing other defensive behaviours – can teach them to stay away, researchers say.

“Unfortunately, there is no way of knowing exactly what attracts a mosquito to a particular human — individuals are made up of unique molecular cocktails that include combinations of more than 400 chemicals,” Chloé Lahondère, a research assistant professor in the Department of Biochemistry said in a news release. “However, we now know that mosquitoes are able to learn odors emitted by their host and avoid those that were more defensive.”

Swatting at mosquitoes can teach them to stay away

In the study, the team demonstrated that mosquitoes exhibit a trait known as aversive learning by training female Aedes aegypti mosquitoes to associate odors (including human body odors) with unpleasant shocks and vibrations.

When the team assessed the same mosquitoes 24 hour later in a Y-maze olfactometer where they had to fly upwind and choose between the once-preferred human body odor and a control odor, the bugs avoided the human body odour – suggesting that they had been successfully trained to identify human by odors and associate those smells with an unpleasant sensation. The team also found that dopamine is critical for aversive learning in mosquitoes. Manipulating the dopamine receptor prevents mosquitoes from learning the smells of hosts.

“Understanding these mechanisms of mosquito learning and preferences may provide new tools for mosquito control,” said Clément Vinauger, an assistant professor of biochemistry in Virginia Tech’s College of Agriculture and Life Sciences. “For example, we could target mosquitoes’ ability to learn and either impair it or exploit it to our advantage.”

The study, entitled “Modulation of Host Learning in Aedes aegypti Mosquitoes” has been published in the journal Current Biology