Some people leave music festivals with a sunburn or a sore throat. Others leave covered in mosquito bites. Last summer, at one of the Netherlands’ biggest music festivals, a team of scientists set out to understand why.
At the 2023 Lowlands Festival in the Netherlands, where tens of thousands came for big music acts, the researchers had a different focus. Inside a row of shipping containers, they were running an experiment to answer a simple question: why do mosquitoes bite some people more than others?
Their findings suggest mosquitoes may be guided by a taste for hedonism.
A Festival of Bites
Led by biologist Felix Hol at Radboud University Medical Center, the research team dubbed their project the Mosquito Magnet Trial, and it’s believed to be the largest real-world experiment of its kind. Over three sticky days, 465 festivalgoers volunteered for science. Their preprint paper was uploaded on bioRxiv.
Each participant filled out a detailed questionnaire on their hygiene, diet, and behaviors at the festival. Then came the test: they placed a bare forearm inside a transparent cage filled with Anopheles stephensi mosquitoes. The cage had tiny holes that were large enough to let the mosquitoes smell the human skin, but too small for them to bite.
The mosquitoes were given a choice: the scent of the person’s arm, or a sugar feeder placed on the opposite side of the cage. A Raspberry Pi camera captured it all.
The results were unambiguous. People who had consumed at least one beer in the 12 hours prior to the test were 1.35 times more attractive to mosquitoes than those who hadn’t. Those who had shared a bed with someone else the night before were similarly appealing, with a 1.34 times greater attraction rate. Meanwhile, participants who had recently showered and applied sunscreen were far less tasty.
“We found that mosquitoes are drawn to those who avoid sunscreen, drink beer, and share their bed,” the researchers wrote. “They simply have a taste for the hedonists among us”.
What’s That Smell?
This study builds on a longstanding mystery in entomology: what makes some humans irresistible to mosquitoes?
We know mosquitoes begin their search for a blood meal by sensing carbon dioxide, which all humans exhale. Once activated, they rely on a mix of smell, heat, and visual cues to home in on their target.
Odor, in particular, plays a key role. Human skin emits volatile organic compounds (VOCs)—molecules like lactic acid and carboxylic acids—that signal our presence to mosquitoes. These scents vary based on diet, skin bacteria, metabolism, and other factors.
But what about beer? Is it the alcohol itself?
Surprisingly, no. The researchers measured blood alcohol levels and found no correlation between how intoxicated someone was and how attractive they were to mosquitoes. It seems the culprit isn’t alcohol in the blood, but how beer changes the way we smell—possibly through metabolic byproducts released in our sweat or skin.
“People who have been drinking alcohol also behave differently, of course,” Hol told Dutch radio Vroege Vogels. “At a festival like Lowlands they might also be dancing more exuberantly, which can also change their body odor”.
Interestingly, wine drinkers also initially attracted more mosquitoes—but this result did not reach statistical significance after adjusting for multiple variables.
The Microbiome’s Role
To dive deeper into what made certain people more alluring, the team also swabbed the forearms of 85 participants, some of whom were mosquito magnets, and others who were practically ignored.
The skin swabs were sequenced for their microbiome composition. Here, again, a faint pattern emerged. People with more Streptococcus bacteria on their skin were modestly more attractive to mosquitoes. These microbes are associated with strong body odors, and while the connection wasn’t strong enough to be conclusive, it aligns with past research suggesting that certain bacteria may amplify mosquito-attracting smells.
Still, the skin microbiomes of high and low mosquito-attractiveness participants weren’t drastically different. Overall bacterial diversity (the range and balance of species) didn’t seem to matter much.
What did seem to matter was showering.
Those who had showered within six hours and applied sunscreen on their forearms were significantly less attractive to mosquitoes.
The sunscreen’s role remains unclear. It may mask natural human odors or contain unrecognized repellent compounds shared across brands. Either way, its effect was clear:
“Individuals that showered recently and used sunscreen on their forearms were still less attractive than individuals who did not use any sunscreen” the authors wrote.
Behaviors That Boost Your Mosquito Appeal
The researchers also probed whether other behaviors—like using cannabis—might play a role. Participants who had smoked weed in the past 48 hours indeed attracted more mosquitoes, but this trend lost significance when all variables were considered together.
Sex, however, stuck. People who slept close to someone the night before were more attractive to mosquitoes, regardless of how recently they had showered.
The reasons are still speculative. It could be physical contact transferring odors. It could be shared bedding. Or it could just be the kind of behavior—intimacy, sweat, proximity—that leaves behind a trail of inviting scents.
Whatever the case, the message was clear: a more intimate, less hygienic lifestyle came with more mosquito attention.
Biting Into Public Health
Mosquitoes are the deadliest animals on Earth, responsible for the transmission of malaria, dengue, Zika, West Nile virus, and the list goes on. Every year, they kill an estimated 2.7 million people.
Understanding how and why mosquitoes choose their victims is a public health imperative. By identifying what draws them in, scientists can help shape new prevention strategies for at-risk regions.
This is why studies like this one, even in a chaotic environment like a music festival, matter.
Although the study focused on a single music festival and a specific group of participants, it still offers useful clues about why certain people tend to attract more mosquitoes than others.
So, Should You Skip the Beer?
Not necessarily. The authors are quick to point out that this is an observational study, conducted in a lively, unpredictable setting with self-selecting participants. Festival-goers aren’t a perfect sample of the general population. And while the correlations are strong, they don’t prove cause-and-effect.
Still, the data speaks. If you want to minimize mosquito bites this summer, you might try:
- Showering regularly
- Applying sunscreen (especially on your forearms)
- Skipping the beer
- Sleeping solo
- And maybe passing on that post-party joint
There’s no single solution. But when it comes to mosquitoes, clean, sober, and solitary may be your safest bet.
So the next time a mosquito hovers nearby, it might be worth thinking about your day—what you drank, whether you showered, or if you shared your bed.
