Are you a mosquito magnet?

Because I am a mosquito   magnet.

Mosquitoes love me.

A mosquito  would bite me no matter my pronouns.

I swear there can be eight people at a  barbecue and every single mosquito makes   a bee line directly to me like I am their personal  barbecue.

That is why I have indoor barbecues, not   recommended by the American Chemical Society.

And  guess what?

If you're a mosquito magnet, we are   not imagining it.

There is really something that  makes us more attractive to mosquitoes, at least.

I always said proboscis when I worked  in a Drosophila lab and it does seem   that that's a valid pronunciation,  but a proboscis is more accepted.

Before we get into why mosquitoes love specific  people more than others, let's walk through what   happens when these mini vampires suck your  blood.

When a female mosquito lands on you,   because it is only the females that bite, it  inserts its proboscis into you.

This proboscis   is a tiny mouthful of six needles that saw  their way into your skin.

Two of the needles   are serrated like a saw blade, but the proboscis  is shaped in a way to minimize pain so that you   don't immediately swat the mosquito off.

There  is a soft part that hits you first, and then the   sawing action is combined with a light vibration  so that less force is required.

Some scientists   are actually trying to design similarly shaped  microneedles for more painless injections,   which sounds good.

So I guess mosquitoes are  finally doing something good for society.

Anyway, mosquitoes don't just suck your blood.

They actually inject some of their saliva into   you as well.

And while scientists are still trying  to tease apart exactly which chemicals in the spit   do what, some of them seem to act as numbing  agents to keep you from noticing you've been   bitten.

Others seem to act as vasodilators and  anticoagulants, keeping your blood vessels open   and your blood from clotting.

Now, there are  over 100 proteins in mosquito saliva and not   all of their functions are even known yet.

But  we do know that that cocktail of chemicals is   also why we get itchy.

So your body actually  has an allergic reaction to mosquito bites,   specifically to some of those 100 chemicals  in the mosquito's spit.

Your immune system   recognizes the foreign mosquito proteins  and starts up a histamine response.

This   brings white blood cells to the area and it also  activates other immune tools that cause itchiness.

And I hate it all so much.

They always  find me and I always get itchy and   sometimes those bites last for weeks.

So  how do they find me in the first place?

Mosquitoes use a bunch of different sensory  clues to find us.

They can hone in on our   body heat.

They can follow the scent of CO2  from our breath.

And I guess also just see us   sometimes 'cause we're really big and the  mosquitoes are really small so they can   see us.

But those big, broad sensory clues  give mosquitoes an idea about where humans   are in general.

Once they find our barbecue,  how do they choose who to chomp down on?

Well,   there's another big way that mosquitoes find us.

It's skin odor.

There have been lots  of studies over the years to figure out   what makes some people smell so much more  delicious to some mosquitoes than others.

Some studies have said that blood type is  involved.

Others indicate that what food or drink   you've consumed might play a role.

Some say that  pregnancy might impact mosquito attractiveness.

And then there are other studies that say that the  presence or absence of a malaria infection might   impact whether or not mosquitoes wanna bite you.

So these studies suggest that people infected with   malaria might smell more attractive to mosquitoes  than others, which is fascinating because that   would make it easier for the malaria parasite  to be passed around.

But different studies have   all shown different magnitudes of effects and  some of them have shown conflicting results.

So it has been confusing until now.

In the past  year, some of the coolest studies I've ever seen   on mosquito attraction have been released and  they have made me feel so vindicated.

The first   was published in the fall of 2022.

It looked at  fatty acids on our skin, specifically carboxylic   acids that we exude in our sebum, a waxy, oily  substance that helps keep our skin moisturized.

And this study was amazing.

The researchers had  participants wear fashion forward nylon stockings   on their arms to collect their sebum, and then  set up a chamber where aedes aegypti mosquitoes   could choose between differently scented nylons.

And the choice was strong.

Those of us who are   mosquito magnets, we really truly are magnetic  to mosquitoes because they chose our scent way   more than others.

Science for the win.

Give me  that peer-reviewed mosquito research all day.

The study looked at the differences in the  compounds between strong and weak attractors   and they found that there were several  different carboxylic acids that showed   up more on the skin of the strong attractors  than the weak attractors.

Specifically, the   strong attractors produced significantly higher  levels of three carboxylic acids, pentadecanoic,   heptadecanoic, and nonadecanoic acids.

They  also found 10 other unidentified compounds in   the same chemical class.

And also, because this  study was done over the course of three years,   they were able to show that it wasn't something  variable like what food the participants had   eaten or whether or not they'd had a beer  recently.

These were stable attractants.

So why are they different between people?

Could be a number of things.

We each might   be genetically predisposed to produce slightly  different skin compounds and the differences   in our skin microbiomes might also influence the  fatty acids that are present.

And as a geneticist,   you know that I am waiting on  the follow-up studies on this.

I didn't have to wait long because in May of 2023,  there was another mosquito magnet study released   from a different group.

It again looked at what  made some people more attractive to mosquitoes   than others.

But this study looked at anopheles  gambiae, another common mosquito species.

And   they used a fancy camera setup that watched  as mosquitoes landed on warm body temperature   targets laced with different smells including  isolated attractants like CO2 and whole body odor   from six different humans.

And the setup for this  was amazing because they put the mosquitoes in a   big caged outdoor arena and then had little pipes  leading away from that arena.

At the end of each   of the pipes were tents that contained the targets  and the different people.

And they had fans that   helped push the human scents through the pipes  into the central arena so that the mosquitoes   could choose where they wanted to fly to.

They put  a fan next to a sleeping human and then attracted   mosquitoes to them.

Just truly delightful.

They  once again found that carboxylic acids were big   differentiating factors between attractive and  non-attractive human scents.

But this time,   they found butyric, isobutyric, and isovaleric  acids leading the pack for most attractive.

Now, they did also find an interesting observation  that the least preferred human subject had a high   abundance of eucalyptol in their body scent.

And  yes, that sounds like eucalyptus because it is   the main component of eucalyptus oil.

Assuming  the person isn't part tree, the compound likely   came from plant-based foods and flavorings  in their diet.

Now, this is just one person.

So this is just a hypothesis-generating  observation rather than a big sweeping   statement.

But could eucalyptol in diets help keep  mosquitoes away?

Maybe, it's a cool hypothesis.

\ And that leads me to my last point,   which is how we, the magnets, can try and defend  ourselves.

You might know that DEET is a big   mosquito deterrent.

DEET is the chemical name  for N,N-diethyl-meta-toluamide.

And basically,   it is super stinky to the mosquitoes and makes  it harder for them to smell us.

We have a short   on how it works if you wanna learn more.

But  what about repellents derived from nature?

Things like citronella candles that everyone  has on their porch in the summer.

Do they work?

No?

A 2017 study found that citronella  scent mosquito repellents really made   no difference in keeping mosquitoes away.

What did work is oil of lemon eucalyptus.

That's pretty cool and makes sense with  what we were just saying.

Even if its   method of action isn't quite clear,  eucalyptus, baby, it's the answer.

So let's try this out with our own homemade  mosquito traps filled with dry ice to give   off CO2.

Because remember, the CO2 and our  breath is one of the biggest attractants to   mosquitoes generally.

I'm gonna put together  four mosquito traps, one with just dry ice,   one with DEET and dry ice, one with citronella  and dry ice, and one with oil of lemon eucalyptus   and dry ice.

I'm gonna leave these out  overnight scattered around the yard,   and then count how many mosquitoes  I capture in each one the next day.

So I failed.

I failed so hard at catching  a single mosquito in Southern California.

So many mosquitoes flocked to me and  I couldn't catch one.

This is the one   time in my life when I wanted a mosquito to  come near me and like nothing, I got nothing.

I have failed you, ACS Reactions  fans, and I'm sorry.

But Andrew and   George are in DC where there are tons of  mosquitoes.

So I decided to send them to   Rock Creek Park and see if they could test  the effectiveness of different repellents.

I don't think their heart was  in it.

I also definitely don't   have IRB approval for human experiments.

My job is weird.