Do Mosquitoes Remember The Smell of Repellents? does a mosquito remember the killer?

Mosquitoes distinguish ‘dangerous’ people
Despite their small size, these mischievous flying insects seem to be more intelligent than we might expect.

According to a recent study published by the newspaper “Current Biology”, a mosquito that is exposed to an attempt to kill a person, distinguishes the smell of this person and does not attack him again, because it feels that it is a threat to its life.

Previous studies had indicated that mosquitoes have certain preferences when choosing their victims, but the recent study said that these intelligent insects can change their preferences and avoid “dangerous people”.

The researchers came to their discovery by using a machine that simulates the hand movements in which a person tries to catch mosquitoes, while spreading the smell of mice near this machine.

Experimentally, the researchers discovered that mosquitoes associate this life-threatening machine with the smell of mice, and that the insects “learned” to stay away from mice.

But the experiment confirmed that mosquitoes’ association between danger and smell occurs only if the source of the danger to the insects is mammals (mice in this case).

“Once mosquitoes associate certain odors with solitary behaviour, their response to that odor is similar to their response to the most effective repellents,” study co-author biologist Jeff Revell said in a statement.

“Mosquitoes remember these smells for days,” Revell added.

Scientists have succeeded in drawing the first complete map of mosquito immune cells, and found a new type of cell that could have a role in the harmful insect’s ability to deal with malaria.

The researchers said the findings, published in the journal “Science”, could help scientists discover new ways to prevent mosquitoes from spreading the malaria parasite to humans, and to break the chain of transmission.

Malaria affects more than 200 million people worldwide and killed an estimated 405,000 people in 2018, mostly infants and children under the age of five.

Malaria is a disease caused by Plasmodium parasites transmitted by the bites of female Anopheles mosquitoes.

Oliver Belker, a molecular infection expert at Sweden’s IMEA University who co-led the study, said: “We discovered a rare type of important new cell, which we called (megasite), which can be a factor in the immune priming, and it appears that it leads to more Immune responses to the Plasmodium parasite.

Belcker’s team explained in the study that the mosquito’s immune system controls how the insect transmits parasites or viruses, but so far, scientists know little about the types of cells.

The team studied the Anopheles gambiae mosquito, which carries malaria, and the Aedes aegypti mosquito, which carries viruses that cause other infectious diseases to humans, such as “dengue fever”, “chikungunya” and “Zika”.

The team analyzed more than 8,500 individual immune cells to see which genes were activated in each cell, and to identify molecular markers for each cell type.

“Mosquitoes seem to have good immunity against parasites such as malaria,” said Sarah Tishman, an expert at Britain’s Wellcome Sanger Institute, who co-authored the study.