Professor Riffell's mosquito school
Mosquitoes are perceived by many people as unloved pests. Mainly because her stitches cause annoying and itchy swelling. But what if mosquitoes could be trained to avoid people? Does that sound unrealistic? But that's exactly what researchers from the University of Washington at Seattle did in experiments with the yellow fever mosquito Aedes aegypti. The scientists have successfully imprinted an odorant on the mosquitoes, which they subsequently avoided. This smell information is the main component of human body odor.
The research team led by biologist Jeffrey Riffell was able to document how the annoying bloodsuckers let go of a victim after they had been shaken off the skin after repeated landing and failed to fail. The mosquitoes memorized this bad experience and looked for another victim. With appropriate training, the researchers succeeded in the mosquitos memorizing a certain odor substance, which is the main component in human body odor. From then on, the pests avoided this negative smell. The results of the study were recently published in the "Current Biology" journal.
The training works as effectively as DEET
"Once mosquitoes have learned to avoid certain smells, these smells cause evasive reactions similar to those of DEET, one of the most effective insect repellents," said Riffel in a press release from the University of Washington on the research results. According to Riffle, the learned smells remained in the mosquitoes' memory for days.
Mosquitoes have preferences
The researchers in the study wanted to learn more about the mosquitoes' learning strategies, because it is already known that the insects have obvious preferences for some people over others. The preferred host at whom you want to suck the blood also depends on the season. In summer mosquitoes prefer birds to eat, in other seasons mammalian blood is on the menu. Riffell and his colleagues wanted to learn more about how learning affects mosquitoes' preferences and how to use this knowledge.
The methods of mosquito repellent
In the first trials, the mosquitoes were vibrated mechanically each time they tried to sting an animal. The vibrations should simulate an attempt to keep the mosquito from biting. The insects quickly learned the connection between the smell and the shock and used this information to decide which host to fly to. This was achieved in rats and humans. In the case of chickens, the researchers were unable to prevent the mosquitoes from being bitten by training.
Dopamine appears to be responsible for the learning process
According to the scientists, learning in many animals such as the honeybee, but also in humans, depends on the 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. "By understanding how mosquitos make decisions about who to sting and how the ability to learn affects their behavior, we can decipher the genetic and neuronal basis of these behaviors," explains Riffell. This could lead to more effective tools for mosquito control. With the new understanding of how mosquitoes avoid certain hosts, the researchers now want to find out how mosquitoes remember preferred hosts. "In both cases, we think dopamine is a critical component," said Riffell. (vb)