Some People Don't Get Bitten By Mosquitoes — Why That's True Will Surprise You

If you can't spend a summer night outside without slapping
your ankles — and you still end up with dozens of mosquito
bites — then it might be true that the flying pests really do
love you.
And those lucky people who say they don't get bitten? They
exist too.
But it's not because one person's blood tastes better to the
small hovering bloodsuckers — or at least, not just that. In a
TED 2014 talk earlier this year in Vancouver, microbial
ecologist Rob Knight explained that the bacteria, or
microbes, on skin produce different chemicals, some of
which smell more attractive to mosquitoes.
The trillion or so microbes that live on skin are a small
percentage of the 100 trillion bacteria that live on and inside
the body, but they play a huge role in body odor. Without
those bacteria, human sweat wouldn't smell like anything.
However, those different bacteria vary greatly from person
to person. Knight explained that while we share 99.9% of
DNA with other humans, most people only share about 10%
of their microbes.
A siren song for mosquitoes
To demonstrate that mosquitoes are overwhelmingly
attracted to certain types of skin microbes, researchers
asked 48 adult male volunteers to refrain from alcohol,
garlic, spicy food, and showers for two days. The men wore
nylon socks for 24 hours to build up a collection of their
unique skin microbes.
Researchers then used glass beads that they had rubbed
against the underside of the men's feet to pick up their
scent as mosquito bait.
Nine men out of the 48 proved to be especially attractive to
mosquitoes, while the scents of seven lucky volunteers were
largely ignored. The "highly attractive" group had 2.62
times as high a concentration of one common skin microbe,
and 3.11 times higher concentration of another common
microbe, compared to the "poorly attractive group." That
poorly attractive group had a more diverse bacterial colony
on their skin as a whole.
Researchers say that it's possible that some people's smell
acts a natural deterrent.
But there's an equalizer for those that naturally draw
swarms of mosquitoes. The same pests are attracted to beer
drinkers.
The study was published in the journal PLOS ONE.