Why do people like the rock

That is why mosquitoes like to bite some people

One bitten, the other spared: some people are real mosquito magnets. But what do the bloodthirsty pests find so attractive about their victims? A current study dares a strange structure - with old socks

Couples and tent partners in particular should know it from mosquito-ridden nights. One is slumbering peacefully and unmolested by the insects, the other is sleepless and stung the next morning. It seems that mosquitoes prefer certain people as their victims. But what makes them particularly attractive to the annoying bloodsuckers?

It's not because of karma or sweet blood: smell plays an important role. The only question is which factors favor certain odors. A British research team led by entomologist James Logan from the London School of Hygiene and Tropical Medicine published a study on this in 2015 in the journal PLoS One. This shows that certain groups of people are preferred by mosquitoes. The experiments showed, for example, that pregnant women and obese people with higher body temperatures are more often plagued. The larger and the more carbon dioxide someone exhales, the more likely they are to become a mosquito magnet. There is also evidence that women and malaria sufferers are more likely to be stung during certain phases of their menstrual cycle.

Collecting socks in the service of science

A current test set-up by the British team is now intended to differentiate these tendencies. New approach: the genes. To do this, the researchers collect 200 socks worn by identical and dizygotic twins from different parts of the world and place them in a Y-shaped wind tunnel full of mosquitoes. So far, a similar experiment has shown that monozygos are stung about the same number of times, but dizygoti are coveted to different degrees. This suggests a genetic connection.

The new experiment is now larger and divided into different ethnic groups. The decision of the animals in favor of certain socks should provide information about the role certain genes play in the formation of odor. "The findings from this experiment can also be used by epidemologists, who can find out which groups of people are particularly at risk," said James Logan of the scientific American magazine.

Mosquitoes are not attracted by the smell alone

The entomologist Zainulabeuddin Syed from Notre Dame names four different odor compositions that people of different ethnic groups produce in his study. One of them, which contains the aldehyde nonanal, is particularly suspected of being a mosquito attractant.

However, Syed points out that there are countless other factors that influence the biting behavior of gnats and mosquitoes: including the weather, the time of year, the sex of the animals, the type of insect, the region and the origin of the people. So there is still a lot of work to be done for the researchers. Until sensible countermeasures can be developed on the basis of these findings, mosquito victims must continue to arm themselves with nets and insect spray - but should take safe measures.

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