New research finds reason some people are mosquito magnets

With the summer season just behind the corner, mosquitoes will, unfortunately, make an unwanted appearance soon. 

Whether you’re off to a beach holiday or staying in the UK, the annoying insects can make summer evenings and nights a nightmare.

While some people seem to always get bitten, others are not at all bothered by the pesky insects.

However, scientists have now unlocked the answer to why some people are plagued by the critters – and others get off scot-free.

Smelly armpits may turn you into a mosquito magnet, according to a new study, published in the journal Current Biology.

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The small insects are drawn to body odour, or BO for short, which they can pick up from 350 feet away.

The new research was based on the African malaria mosquitoes, Anopheles gambiae, which were let loose in an ice rink sized outdoor setting in Zambia.

First author of the study, Dr Diego Giraldo, said: “This is the largest system to assess olfactory preference for any mosquito in the world. And it is a very busy sensory environment for the mosquitoes.”

The research team from Johns Hopkins University, Baltimore, released 200 hungry mosquitoes each night to observe how often they landed on evenly spaced pads heated to 35ºC, mimicking human skin.

Body odour proved a more attractive bait than CO2, which is a known cue for mosquitoes.

However, further tests showed the swarm of 200 biters were also picky. 

The aromas of six volunteers, sleeping in surrounding single-person tents, were piped onto the pads over six consecutive nights.

This approach enabled the researchers to record the mosquitoes’ preferences and collect nightly air samples from the tents to compare airborne components of body odour.

Senior author, Dr Conor McMeniman, said: “These mosquitoes typically hunt humans in the hours before and after midnight.

“They follow scent trails and convective currents emanating from humans, and typically they will enter homes and bite between around 10pm and 2am.

“We wanted to assess mosquito olfactory preferences during the peak period of activity when they are out and about and active and also assess the odour from sleeping humans during that same time window.”

The researchers managed to identify 40 chemicals that were emitted by all of the humans, though at different rates.

Co first author, Dr Stephanie Rankin-Turner, said: “We don’t really know yet exactly what aspect of skin secretions, microbial metabolites, or breath emissions are really driving this, but we are hoping we will be able to figure that out in the coming years.”

People who were more attractive to the pesky insects consistently emitted more carboxylic acids produced by skin microbes.

Furthermore, one volunteer, who had a strikingly different odour, consistently attracted very few mosquitoes.

This person gave off triple the amount of eucalyptol, which describes a plant compound found in oils, herbs and spices. 

Elevated levels of this substance may be related to diet but the research team hasn’t established a firm conclusion.

The researchers were surprised by how effectively the mosquitoes could locate and choose between potential human meals within the huge arena.

They are hoping that this study will lead to the development of more effective repellents and traps.