Mosquitoes can be trained to stop stinging these people

The mosquito school of Professor Riffell

Mosquitoes are perceived by many people as unpopular pests. Mainly because their stitches cause annoying and itchy swellings. But what if mosquitoes could be trained to avoid people? Sounds unrealistic? But that's exactly what researchers from the University of Washington at Seattle have done in experiments with the yellow fever mosquito Aedes aegypti. The scientists have managed to memorize the mosquitoes an odorant, which they then avoided. This odor information is the main ingredient of human body odor.

The research team led by biologist Jeffrey Riffell was able to document how the annoying bloodsuckers left behind a victim after they were shaken off the skin after repeated landing and did not come to the trick. This bad experience impressed the mosquitoes and looked for another victim. Through appropriate training, the researchers were able to show that the mosquitoes imprinted a particular odorant, which is the main component in human body odor. From now on, the evil spirits avoided the pests. The results of the study were recently published in the journal "Current Biology".

Researchers have succeeded in teaching mosquitoes, to avoid human body odor and thus not to approach people. (Image: nechaevkon / fotolia.com)

The training is as effective as DEET

"Once mosquitoes have learned to avoid certain odors, these odors cause similarly strong escape reactions as DEET, which is one of the most effective insect repellents," Riffel says in a recent press release from the University of Washington on the research findings. According to Riffle, the learned smells were kept for days in the memory of mosquitoes.

Mosquitoes have preferences

Researchers wanted to learn more about the mosquito's learning strategies, as it is already known that the insects have obvious preferences for some people over others. Also, the preferred host in which they would like to suck the blood, depending on the season. In the summer, mosquitoes prefer birds for food, and in other seasons, mammalian blood is on the menu. Riffell and his colleagues wanted to learn more about how learning influences the mosquito's preferences and how to use that knowledge.

The methods of the mosquito school

In the first few attempts, the mosquitoes were subject to mechanical shock due to vibration every time they tried to sting a test animal. The vibrations should simulate an attempt to keep the mosquito from stinging. The insects quickly learned the connection between the smell and the shock and used this information to decide which host to approach. This succeeded in rats and humans. In chickens, researchers were unable to prevent the mosquitoes from training by biting.

Dopamine seems to be responsible for the learning process

According to the scientists, in many animals such as honeybees and humans, learning depends on dopamine in the brain. Further experiments by Riffell and his team showed that dopamine is also important in the mosquito learning process. Genetically modified mosquitoes without dopamine receptors lost their ability to learn.

Results can help fight infectious diseases

According to the researchers, the study results could have important effects on the control of mosquito-borne diseases. "Understanding how mosquitoes make decisions about who to sting and how their ability to learn influences their behavior enables us to decode the genetic and neuronal foundations of these behaviors," explains Riffell. This could lead to more effective tools for fighting mosquitoes. With the new understanding of how mosquitoes avoid certain hosts, the researchers now want to explore how mosquitoes remember preferred hosts. "In both cases, we think dopamine is a critical component," says Riffell. (Vb)