"They Simply Have A Taste For The Hedonists Among Us": Festival Mosquito Study Has Some Bad News

If you live in or visit an area with mosquitoes, you are probably well aware that the little bastards insects have a tendency to snack heavily on some people, whilst leaving other individuals unscathed.

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Scientists have attempted to figure out if this is true, and why this might be the case. There have been suggestions, not well-supported by evidence, that mosquitoes may prefer certain blood types or particularly "sweet blood". Overall, it appears that mosquitoes are indeed attracted to certain individuals over others, sometimes choosing the same target night after night despite plenty of available meals, and part of the answer is to do with odor.

In a new study, which has not yet been peer reviewed, researchers recruited 465 participants to study the phenomenon in a more natural setting than a lab: a music festival in the Netherlands.

At the festival, the team asked volunteers to fill in questionnaires about their hygiene, diet, and activity at the festival. This included how much alcohol they had consumed, and their sleeping arrangements for their stay (including whether they were alone), as well as the usual demographic questions.

After that, it was time to set some mosquitoes loose and see which of the participants the insects were most attracted to.

"Mosquito attraction was measured using a custom designed setup: a transparent cage with perforations where female Anopheles mosquitoes were offered a choice between a sugar-feeder and the participants arm," the team explains in their paper.

"Mosquitoes could only smell, not bite, the participant’s arm. Attraction was quantified through video imaging, measuring arm landings relative to total landings. Mosquito attraction was correlated with questionnaire responses and skin microbiota profiles collected from forearm skin swabs."

The team discovered that mosquitoes were less attracted to festival-goers who wore sunscreen, and who had skipped their usual shower routine. As well as this, they found that individuals with more Streptococci on their skin were more attractive to the insects.

But more important was whether the participants had drunk beer, and whether they had slept alone. Those that had drunk beer specifically – blood alcohol levels did not have a noticeable effect – were significantly more attractive to mosquitoes, as well as those who had not slept alone.

"The general picture that emerges from our study suggests that a sober life-style – abstaining from drugs and alcohol, sleeping alone, and applying sunscreen regularly – lowers one’s chances of getting bitten by mosquitoes," the team explains. "While we found no evidence supporting popular myths such as blood type influencing bite frequency, we were unable to assess the existence of so-called ‘sweet blood.’ Ultimately, enjoy the next festival or camping trip as you like – but it seems mosquitoes may have a soft spot for those making less responsible choices."

Though an interesting study, looking at a fairly natural environment, the team notes a few caveats, including that the participants were a self-selecting group of music-loving science enthusiasts.

"While our findings are intriguing, there may be other contributing factors yet to be identified," the team adds. "Further research is certainly needed before we suggest rejecting a beer solely to avoid mosquito bites."

But if you do enjoy a beer, consider slathering yourself up in sunscreen first, or maybe forgoing your wash.

The study is posted to pre-print server bioRxiv.