Mosquitos seem to like beer drinkers who recently had sex

Countless factors may (and may not) contribute to a mosquito’s thirst for your blood over others. And while there’s no single answer to this millennia-old question, researchers at Radboud University Nijmegen in the Netherlands think they identified at least a couple influences that may increase your insect attractiveness: booze and certain nocturnal activities.

While the team’s study is still in review ahead of its publication, their experiment offers an interesting and possibly life-saving approach to studying mosquito behavior. The blood-suckers are by far the world’s deadliest animal because they serve as vectors for dangerous diseases like dengue, West Nile, Zika, and malaria. It’s estimated that mosquitos are directly responsible for around 2.7 million deaths every year, while millions more must deal with the pathogens’ often severe symptoms.

Managing mosquito populations and preventing the spread of disease are vital to global public health, and those endeavors can benefit from a better understanding of who is most often targeted by the pests. Entomologists already know one of a mosquito’s first tip-offs to a potential meal is the carbon dioxide exhaled by their unsuspecting hosts as they breathe. A litany of additional sensory cues also play a part in where the insects land, but previous research suggests that olfactory indicators may be a particularly strong guide for mosquitos.

Researchers led by biologist Felix Hol decided to investigate what biological and sensory contributors may have the most sway over a mosquito’s dining habits. But instead of asking volunteers to come to their lab, they visited a location known to boost the body’s physical responses: an outdoor music festival.

For three days in 2023, Hol and colleagues oversaw a pop-up laboratory inside connected shipping containers at Lowlands, a music festival that takes place every year about 42 miles east of Amsterdam. They then asked concertgoers to fill out a questionnaire about some of their most recent (and personal) hygiene, diet, and lifestyle decisions. 

Roughly 500 music fans volunteered to not only answer the survey, but stick their arms into a custom-designed cage buzzing with hungry mosquitos. Importantly, none of the participants were in any danger of covering their arms in itchy welts. Researchers built the apparatus to feature holes that were tiny enough for the insects to smell a person, but not pierce their skin using their needle-sharp proboscis. The team then recorded videos of the mosquito responses compared to responses to a sugar feeder placed on the other side of the cage. After analyzing the accumulated data, the study’s authors noted that their insects often displayed a “clear preference.”

To put it politely: they enjoyed people who enjoyed themselves. Those who drank beer and had sex the night before the experiment were around 1.35 times more attractive to mosquitos than the more sober, abstinent volunteers. Conversely, the pests were less likely to try snacking on an arm if it had been recently washed and/or had sunscreen applied to it.

The researchers’ self-titled “Mosquito Magnet Trial” is the largest study of its kind to date to their knowledge. At the same time, they conceded their experiment took place in a “loosely controlled setting,” with a selection bias towards “science-loving festivalgoers,” and that more investigation is needed before drawing any concrete conclusions. Regardless, they felt confident in asserting that mosquitos “are drawn to those who avoid sunscreen, drink beer, and share their bed.”

“They simply have a taste for the hedonists among us,” they wrote.
But even if their theory eventually requires some caveats, the overall suggestions are backed by science. It’s never a bad idea to limit your alcohol intake, while applying sunscreen daily. As for that third habit, consensual fun is scientifically certified for your health.

 

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