Some people can spend an entire summer evening outdoors without a single mosquito bite, while others end up covered in itchy welts within minutes. Many blame their blood type or simply bad luck, but the latest research suggests that mosquitoes are far from random when choosing their targets.
Mosquitoes start choosing their victims from several metres away
“We have known for over 100 years that mosquitoes are attracted by the carbon dioxide that we exhale – this is the first signal that triggers their behavior.” Swedish researcher Rickard Ignell told AFP.
He explained that the insects can detect this cue from 11 metres away, allowing them to sense that a human is nearby.
As reported by ScienceAlert, once mosquitoes are within roughly ten metres of a person, they begin to detect body odours as well. “Odours, in combination with carbon dioxide, become even more attractive to mosquitoes,” said Ignell, who led the recent study.
As they move closer, body heat and moisture further increase the appeal of certain individuals, making some people significantly more attractive targets than others. Researchers say every person has a unique chemical profile. Billions of bacteria living on our skin produce hundreds of different compounds, and some of these appear to be particularly enticing to mosquitoes.
A chemical produced on the skin may make you irresistible to mosquitoes
“The mixture of compounds produced by the microbes living on our skin can be more – or less – attractive to mosquitoes,” explained one of the researchers.
Studies suggest that the human body emits between 300 and 1,000 different volatile compounds. Scientists are only beginning to understand which of these chemicals are responsible for attracting mosquitoes.
In a recent Swedish-led study, researchers analysed the body odours of 42 women while observing which participants were favoured by the bloodsuckers known to spread yellow fever and dengue. The team identified 27 compounds that the insects could detect.
Among them, one substance stood out: 1-octen-3-ol, also known as mushroom alcohol. Participants who produced larger amounts of this compound were bitten far more frequently than others.
Researchers were surprised to discover that even relatively small increases in the level of this substance made a noticeable difference. The study also indicated that pregnant women, particularly those in their second trimester, may be especially attractive to mosquitoes.
If you missed it: Hungarian pet owners may soon have new obligations under EU plans
Blood type does not appear to be the deciding factor
Contrary to popular belief, there is no convincing scientific evidence that mosquitoes strongly prefer one blood type over another. Likewise, hair colour, eye colour and skin colour do not appear to play a major role in determining who gets bitten.
Instead, researchers believe that the composition of the chemicals released by our bodies, the amount of carbon dioxide we exhale, and factors such as body temperature and perspiration are far more important.
Could beer make you a mosquito magnet?
A Dutch study has also suggested that drinking alcohol may increase the likelihood of being bitten by mosquitoes. Beer can raise body temperature, increase carbon dioxide production and alter body odour, potentially making people more attractive to the insects. In the study, participants who had consumed beer within the previous 24 hours attracted significantly more attention from mosquitoes than those who had not been drinking.
Researchers say the issue goes well beyond itchy bites. As climate change allows disease-carrying mosquito species to expand into new regions, understanding exactly how these insects choose their hosts could become increasingly important for public health and disease prevention.
