SciShow Tangents - Mosquitos

Episode Date: September 28, 2021

Summer's over, which is a bummer, but now's the perfect time to remember that summer isn't all perfect. It brings sunburns, too-hot car seats, and, worst of all, blood-sucking mosquitos! So let's embrace the beginning of fall by talking some smack about those nasty, itchy, little guys!Head to https://www.patreon.com/SciShowTangents to find out how you can help support SciShow Tangents, and see all the cool perks you’ll get in return, like bonus episodes and a monthly newsletter!A big thank you to Patreon subscribers Eclectic Bunny and Garth Riley for helping to make the show possible!Follow us on Twitter @SciShowTangents, where we’ll tweet out topics for upcoming episodes and you can ask the science couch questions! While you're at it, check out the Tangents crew on Twitter: Ceri: @ceriley Sam: @slamschultz Hank: @hankgreen[Fact Off]Millipede toxins as mosquito repellent https://link.springer.com/article/10.1023/A:1026489826714https://link.springer.com/article/10.1007%2Fs00114-003-0427-2https://www.springer.com/gp/about-springer/media/research-news/all-english-research-news/madagascar-s-lemurs-use-millipedes-for-their-tummy-troubles/15982512https://www.nytimes.com/2000/12/05/science/for-monkeys-a-millipede-a-day-keeps-mosquitoes-away.htmlhttps://www.mdedge.com/dermatology/article/198138/wounds/whats-eating-you-millipede-burnshttps://www.ncbi.nlm.nih.gov/pmc/articles/PMC7504811/Vampire jumping spiders eating mosquitoeshttps://www.npr.org/sections/goatsandsoda/2018/04/17/601896991/what-you-learn-when-you-put-smelly-socks-in-front-of-mosquitoeshttps://www.theguardian.com/global-development/2015/aug/05/mosquito-eating-vampire-spider-could-be-recruited-for-war-on-malariahttps://www.mentalfloss.com/article/53382/meet-vampire-spiderhttps://www.livescience.com/5818-spiders-attracted-blood-perfume.htmlhttps://www.livescience.com/1214-killer-spiders-prefer-malaria-mosquitoes.htmlhttps://www.livescience.com/20800-vampire-spiders-blood-meal.html[Ask the Science Couch]Attracting mosquitoeshttps://www.sciencedirect.com/science/article/pii/S009286741400155Xhttps://link.springer.com/article/10.1007/s10886-015-0587-5https://www.cell.com/current-biology/fulltext/S0960-9822(19)30215-5https://www.niaid.nih.gov/news-events/how-mosquitoes-smell-human-sweathttps://www.researchgate.net/publication/229127147_A_Review_of_Mosquito_Attraction_Studies_Important_Parameters_and_Techniqueshttp://www.sciencepublishinggroup.com/journal/paperinfo?journalid=547&doi=10.11648/j.aje.20190302.13https://academic.oup.com/jme/article/41/4/796/885285https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5949359/https://www.sciencedirect.com/science/article/pii/S0960982219306943[Butt One More Thing]Mosquito anus blood pre-urinehttps://www.nytimes.com/2011/12/20/science/how-hungry-mosquitoes-cool-themselves.html

Hello and welcome to SciShow Tangents, it's the lightly competitive knowledge showcase. I'm your host Hank Green and joining me as always this week is science expert, Sari Reilly. Ahoy. And also our resident everyman, Sam Schultz. Hello. Well, you guys, I had a question I wanted to ask you, but I am looking at my show notes and it does say, Hank and panel chat,

remember the Beagle impression. No. I thought it would be unfair for me to delete it, so I commented, Sam, no. I'll do it be unfair for me to delete it, so I commented. Sam, no. I'll do it for a special occasion. Okay. Check out the bonus episode this month to hear Sari's beagle impression.

Oh, perfect. It's just for Patreon patrons. If you support us on Patreon, I will commit to that. Yeah. Okay. All right. Wow. Okay.

Well, my question that I wanted to ask you is somewhat related. Catherine and I are going to be getting a cat, I think. What should we name our new cat? Tuna. Tuna's a good cat name. I do have a friend named Tuna. It might be a little weird. I had a friend who got a dog and named it Hank. And I was like, excuse me? Like, we're friends. I see you all the time. This is going to be weird. And it was. Like, whenever I'm over, she talks to the dog and I'm like, ah, it's very confusing. Does she call you both Hank or does she call him dog Hank or anything like that? No, she just says Hank. And I have no idea. It's like, did you want me to go outside? I don't know. I'd like to, yes,

I would like to go outside. Usually people don't ask me if I want to go for a walk when I'm over at their houses, but that's lovely. Sure. It does sound nice, yeah. Would you like a treat? Would you like to go for a walk? All those things sound like nice offers. Yes. Yes, it sounds great. Boy, being a human sucks.

Okay, so Tuna is one option. I'm going to give Tuna an option now. Tuna, what do you want me to name the cat? Sam. Oh, come on. This is terrible. Sam the cat? Oh, come on. This is terrible. Sam the cat? Yeah, come on.

That's it. That is a great cat name. Yeah. It's a fantastic cat name. Stationary. Is that a nice name for a cat? No. No, I think Pencil's a better name for a cat than Stationary.

Stationary's too many syllables. Oh, Pencil. I like Pencil. Frankenary is too many syllables. Oh, pencil. I like pencil. Frankenstein. I have Frankenstein on my desk. Okay, good. Frankenstein is kind of a cool name for a cat, actually. Well, especially if you're Sam.

Okay. And are very excited that we are approaching your primary season. Well, what are you going to name him? Saturn or something? Yeah, that's kind of good. There's a bunch of astronomical objects we could go with. I usually like naming animals after food. So my dog's name was Taffy. But like any sort of food that's two syllable.

So like dumpling, mochi, carrot. Pizza. Anything really longer than one syllable even. Like corn, not quite. Yeah. You can't quite call a cat corn, but you could call it corny. Or corn. Yeah, you wouldn't want delicata squash, but you could do pumpkin.

It's true. There is a point at which there's too many syllables. Yeah. Yeah. What do you want to name the cat? I don't know yet. This is why I need ideas. I was thinking about Earl Grey.

I thought Earl Grey was kind of cute. But then you have to call on your cat Earl all the time. That's fine. You can call him Grey. Or Grey. Well, I think we gave you a lot of great options. Thanks, everybody. If you want to tell us more things to name my cat,

we're on Twitter at SciShow Tangents. And now it's time to get into the show. Every week here on Tangents, we try to one-up a maze and delight each other with science facts while also trying to stay on topic. We have some panelists here. They're playing for Hank Bucks and also for Glory. I will be awarding them Hank Bucks. And at the end of the episode, whichever one has more will be crowned the winner. Now, as always, we introduce this week's topic with the traditional science poem. This week, it is from me. Everybody's always asking me why we don't kill all mosquitoes. They suck your blood and spread disease and bite me on my bum. So if we can make a space station and microwave taquitos,

then why don't we just unalive every single one? Make a special laser that can shoot them off from space, or modify their genes so they turn into goopy paste, or find a nasty chemical that melts their little face. Ask the to do it i know they'll find a way but if you want to know why we don't kill all mosquitoes there is no doubt in my mind that if we could it would be done because yeah we got a space station and microwave taquitos but we're absolutely powerless against this little bug so the topic for the day is mosquitoes which are there's like 3 000000 species of mosquito. There's a lot of them out there.

Few species cause a lot of problems for people. Not just itchiness, but also some of the worst diseases that we deal with as a species. But I guess there's probably a pretty clear line that is drawn around the animals that we call mosquitoes. Yeah. So they're a subset of flies. Oh. They're small flies. Okay.

So they're in the order Diptera, but they're specifically within the family Culicity from the Latin culex, meaning gnat. So they're just like a smaller subset of fly. Do they all have the same lifestyle where they drink blood? No, many of them don't.

Many of them like drink nectar or... I think they all have elongated mouth parts, but they have like a variety of nutrients. I was surprised to find out that mosquitoes drink nectar and like can be pollinators where I'm like, God dang it. Now I don't hate all of them. But that's the thing. You can keep a lot of mosquitoes with no negative impact. But if you could unalive every single Aedes aegypti, then that's an A plus for everyone. Yeah, I think like very relatively few.

I don't want to say very few, but relatively few of those over 3,000 species bite humans, suck blood and transmit disease. And even that, it's only the females that do it because they need the iron and protein from the blood to make eggs, I think. So really, the proportion of mosquitoes that are very, very bad and very, very deadly for humans is quite small compared to all the mosquitoes that exist. But they're just, they're little suckers. They're bad. Yeah.

They're industrious in their evilness. They're very good at it. Yeah. The word mosquito sounds like it was, well, it sounds to me Spanish. Mm-hmm. Ah. And it, but I could not tell you, it's a little something. Yeah?

Yeah, like a taquito is a little taco. Yeah. A mosquito is a little mosca, which means fly. Oh. Oh. So just like the species the species classification that flies yeah yeah a little fly okay well there you go pretty straightforward pretty straightforward all right well i'm glad to know a little bit more about mosquitoes and that i shouldn't be

mad at all of them just a few of the 3 000 species that's a wild number of mosquito species and so it is time for our first game of the show, and we're going to be playing Truth or Fail. Male mosquitoes have a pretty short lifespan, generally lasting about a week. But what they lack in lifespan, they make up for by trying to mate a whole lot, many, many, many times until they die. But the pursuit of that goal can create potential problems for them and their fellow mosquitoes. The following are three tales of possible mosquito mating miscalculations. Only one of them is true. Which one is it? It could be fact number one. When they're ready to mate, male mosquitoes hold their pee so that their bodies will swell up, which scientists hypothesize is a way for male mosquitoes

to look larger and impress their potential mates. Unfortunately, holding their pee makes them a more hospitable home to bacteria that they can then pass on to their mate and even to their young. But it also could be fact number two. Male mosquitoes will attempt to beat their wings at a similar frequency as a female mosquito to show off their fitness. So they like have a nice converging wing beat pattern. But all the energy that they put into showing off and mating comes at the expense of their ability to fight parasites, which is a trait that they can pass on to their male offspring. Or it might be fact number three. In the hours before they begin mating, male mosquitoes consume more nectar to

ensure that they have enough energy, even stockpiling some of that extra nectar on their legs to carry around with them so that they can drink it after they have used up what is in their belly. But as they gather all that stuff for mating, the combined smell of the nectar can attract hummingbirds who are happy to eat both the insect and the sugar alike. So is it fact number one, holding onto their pee makes them hospitable to bacteria? Or fact number two, flapping their wings at the same species as females makes them more susceptible to parasites? Or fact number three, they just become delicious little bird feeders? They can pass on being more susceptible to parasites to their children?

Or they pass on the parasites to their offspring? They pass on apparently just sort of a decreased immune function to their kids. So it like damages their DNA to do the thing that they do or what? I think it may be that they pass the same genes on. So like the genes that make them do the fun flapping. Oh, the hot dog in genes. Yeah. The show off genes. Yeah. Okay, the hot dog in jeans. Yeah. The show-off jeans.

Yeah. Okay. Okay. The horny man jeans. Yeah. Oh, hold in their pee. I mean, I guess if you can, I don't know. I don't know anything about how bugs go to the bathroom.

I also don't know. I was also thinking, I think they poop. I don't know if they pee. I feel like they would do what birds do, and it would just come out when it was time and it would be poop and bee combined. It's so small that we don't even see it most of the time. Yeah.

So y'all are correct. When I say pee, I mean liquid being excreted from the cloaca, which is technically, I think, poop because it just goes through the digestive system and isn't filtered out of their blood. Okay. Gosh. And the hummingbird one is just delightful.

That they would save a snack for later. Yeah. I guess I, I am having trouble wrapping my head around what that looks like. Cause I can just imagine like a bee with pollen on its little legs. And imagining a mosquito with like a drop of nectar on its leg. Wouldn't that get in the way if they're, I guess I don't know. I assume because they have cloacas that their mating also looks like a cloacal kiss of some sort.

Are you going to get nectar all over? Like just spread it as you're in the middle of mating or as you're like flying around brushing up against leaves. Can a little blob of nectar even get that small? How small can blobs of liquid get? I don't know. I mean, you know how like bees have like special places to stick it. Yeah, yeah, yeah. Yeah.

Well, the first two are so similar in that they make it susceptible to something in a specific way that I feel like one of those two must be true. I don't know why I feel that way, but I do. I think I just can't wrap my head around the wings humming one. They definitely make their whining noises, but I can't figure it out. And so I'm going to go with holding their pee because that seems like a dumb thing that an animal would do. Just like mate more.

I'm also going to go with holding pee. Oh, we got two of you for holding the pee. Well, Sam, I got to say you were right. You were absolutely right. You go with the thing where like, that seemed very similar. It must be one of the two. Uh-huh. But you both went with the wrong one. Oh, it just seems not possible

to make that genetic or whatever. Yeah. So firstly, for the pee holding, this is kind of a thing. So when female mosquitoes feed on blood, um, so first thing to know, male mosquitoes drink nectar, which is wild to me. And also the, sometimes you're like here are two mosquitoes. There's like the male ones and they're really big. And the females are really little. I don't know if that happens in some species, but I know that it's not typical. Like these may be two different species, but like in the mosquitoes that we generally see,

the male and the female are the same size. They look a little bit different. If you've got a microscope, you can like see the difference in their faces and stuff, but they're, you know, you're not going to notice. But the male mosquitoes just drink nectar and they can chunk themselves all up. But this is a thing that they did try to exploit with female mosquitoes because they do drink just a ton, a ton, a ton. And then they have to pee out the stuff they don't need in the blood and so they have created a insecticide that actually prevents female mosquitoes from peeing and that makes them

sometimes literally explode uh but other times just be sort of lethargic and they are less able to have more blood meals and that decreases the number of eggs that they can lay. But so this wild situation with the wing flapping, first of all, this is mosquito courtship. Like a male mosquito tries to match his wing beats to the female mosquito. And I think that she even like tries to change her wing beats to see if he can keep up. Like it seems to be a test of fitness where if you are able to do that, then you are, you have been a successful male mosquito. That's fine. But, and I don't actually know the mechanism of how it is passed on, but scientists found that the male babies of

male mosquitoes who were good at doing this wing flap converging matching harmonic convergence is what they call it uh the male offspring were less able to mount immune responses to parasites so there's a specific thing called humoral melanization which is a mechanism that helps mosquitoes fight pathogens and parasites where they coat the threat with melanin which is cool that's not how we do it that's a whole separate immune function that other animals have. And they're just less able to do that. Whereas the female offspring of those male mosquitoes don't have that problem. But probably just because they have much more energy in the form of blood meals to do good immune stuff.

So why? I don't really know. It shouldn't matter because all the good egg juice comes from the female. So I'm not sure what the mechanism is, but that is what the scientists found. That's weird. Yeah. It is weird. And hummingbirds will absolutely eat mosquitoes.

But do they have nectar pouches? They don't have nectar pouches. Okay. I was going to be very startled if they did. If their legs were just like little honey pots. Yeah. Well, we're headed into the break with a score of 0-0. So it's all going to be decided when we come back for the Fact Off.

All right, everybody, welcome back. It's time for the fact off. Our panelists have brought science facts in an attempt to blow my mind. And after they have presented their facts, I will judge which one of them will make the best TikTok and then I will award Hank Bucks any way I see fit. But to decide who goes first, I have a trivia question for you. Toxorhynchides, I have no idea if I'm saying that right, is a genus of mosquito that does not suck blood.

As adults, they eat things like sap and nectar, but as larvae, they cannibalize other mosquito larvae, earning them their nickname of mosquito eater. How many species of mosquito eaters are there in the genus Toxorhynchides? Well,

it's less than 3,000. Yeah, somewhere between one. Yeah. Well, two probably because there's more than one species, I bet, and 3,000. So I don't know, Sam, do you have any special insight into mosquito eaters? Can there be a genus of one? Does that exist? Yeah, there can.

Okay. I think there are five. Five. Yeah. I was going to go with 200. There can't be that many. They'd be eating each other too much. What?

Then we'd have no mosquitoes and our problem would be solved. Okay. Well, regardless, the winner is Sam Schultz. There are 92. Yes. Well, regardless, the winner is Sam Schultz. There are 92. Yes. So you were not particularly close. And Sari, you almost got in there. She wasn't particularly close either if I wasn't particularly close.

No, neither of you were close. You were quite close in how far apart you both were. Yeah. So you were 92 away and Sari was like 103 away. You know, it's close in that way. So Sam, that means you get to choose who goes first. You go first, Sari. Okay.

There are plenty of human-made mosquito repellents on store shelves, but nature has brewed up some potent chemicals too. For example, quinones are a class of many different organic compounds with a six-carbon ring and two carbonyl functional groups. You don't need to remember that just for the chemistry nerds out there. And for example, there are a group of millipede species that produce benzoquinones for defense, spraying a noxious scoop that could corrode the outsides of predators or whatever's annoying them or be otherwise toxic and unpleasant. And in a 2003

study, researchers tested out two benzoquinones, toluquinone and MMB, as a mosquito repellent. They laid out some wells of human blood covered with a nylon and silicone membrane, some plain and some applied with these toxins. They tested Aedes aegypti mosquitoes, the ones that you probably hear about in the news that carry yellow fever, Zika, and parasitic bot fly eggs, to name a few of many horrible pathogenic things. And they found that the female mosquitoes landed less frequently, fed less frequently, and flew around more, which maybe indicates being repelled on the benzoquinone-protected blood. They didn't look deeply into why the mosquitoes are repelled, but like I said, benzoquinones are super toxic. And besides that, in other papers,

this class of compounds has been shown to kill a aegypti larvae in lab settings. So it's probably some combination of those things. Now, unfortunately, we can't just slather millipede goo on us and call it a day because our skin gets so-called millipede burns with pain and usually dark red, blue, or black staining, kind of like it's burned or rashy or dead skin, which is so fun to think about and look at. Do not look at it. Oh, I'm looking it up right now. But some non-human primates take full advantage of this gooey mosquito repellent. For example, some lemurs on Madagascar find secheltis millifeeds crawling around when it rains, chew them like bubble gum to get all the goopy benzoquinones out, then rub their bodies with the carcasses, especially around their butts.

And some South American capuchin monkeys go looking for orthoporus dorsovitatus millipedes in logs or mounds of dirt. They also pop the millipedes into their mouths to make them mad or crush them up and rub the secreting insects all over their fur. And even if a capuchin wasn't lucky enough to find a millipede on its own, it might get one from a friend who's done lathering up, or they might just rub up against a friend to steal some of that mosquito-repelling goo from their fur. I guess kind of like a parent stealing extra sunscreen

that wasn't fully rubbed into their kid's skin. I don't know, my parents did that. Just rubbing your child on you? Yeah. Yeah, okay, I'm there with you. And so for these mammals, researchers assume that it's worth the pain from the toxins, Just rubbing your child on you? Yeah. Yeah, okay. I'm there with you. And so for these mammals, researchers assume that it's worth the pain from the toxins, especially during the rainy season when disease or parasite-carrying mosquitoes are abundant and give them big botfly cysts, along with lots of other insect pests.

Because the benzoquinones are unpleasant, like I've been saying over and over, and the primates often drool or look agitated while using them. And when a monkey researcher named Dr. Eisner tried sticking a millipede into his mouth, quote, he immediately fell to his knees. It was so painful and irritating. Oh, wow. So he wanted to see what the monkeys were experiencing. Well, yeah, but he's not a monkey. Yeah.

I once fell to my knees after eating a donut but because it was so good that's why we've grown soft we have donuts and stuff we can't be putting millipedes in our mouths anymore yeah we can't put no absolutely not i loved that we've done the research to like ensure that this is a mosquito repeller but did we have to when like monkeys were clearly going through personal discomfort to rub it all over themselves? They're like, we just got to make sure. We want to test mosquitoes and some blood. That's a tough one to beat, Sam. What do you got? Okay, this week, I have a little bit of an early Halloween treat for you.

Oh my God, I'm not surprised. There's a species of jumping spider in East Africa known as the vampire spider. And as its name would imply, the spider's top favorite food, it can eat other stuff, but its top favorite food is blood, specifically mammal blood. Unfortunately for the vampire spider, they do not have fangs that allow them to pierce through the flesh of any mammal to actually drink the blood. So they have to get it in a more roundabout way. And that is by hunting down and eating mosquitoes who have just eaten a mammal blood meal and they aren't just like indiscriminately hunting for mosquitoes and hoping to

catch one that just drank blood numerous lab tests have shown that they specifically look for the visual cues of female mosquitoes because like we mentioned male mosquitoes don't drink blood in species of mosquitoes that drink blood. Specifically, the female mosquitoes have non-fuzzy antennas, while male mosquitoes have fuzzy antennas. So to confirm this, scientists in 2012 added another classic movie monster to the mix by creating what they called Franken-mosquitoes, which were just different combinations of male and female mosquito body parts that were glued together and then dangled in front of vampire spiders to see what they went for. If a Franken-mosquito had fuzzy antenna, like a male mosquito, the spiders were way less likely to attack, even if the Franken-mosquito had a blood-filled stomach, which was one of the pieces they could glue on to. When they find their

prey, they pounce on and devour them, the vampire spiders do, and some of the younger spiders can even jump and snag them in midair. They seem to have a preference for uh the malaria carrying species of mosquitoes anopheles i think is that that's one of them maybe yeah because they're easier to catch i think they have like a bigger blind spot or something so it's easier to sneak up on them and then some researchers have suggested that you could use these spiders as a useful all-natural method of malaria control but to do that you'd have these spiders as a useful all natural method of malaria control. But to do that, you'd have to release tons of spiders like into communities and into people's homes. So I don't know if that's super useful.

But why do they have this preference for blood? And they go to so much trouble to get it. It's very nutritious for one. But in tests, spiders who have recently eaten mammal blood are four times more attractive to mates based on their smell. So it makes them sexy, just like it makes real vampires sexy when they drink blood. And then one more little fact that I couldn't tie to vampires exactly. Tests have shown that these spiders are, much like mosquitoes, attracted to that smelly sock smell that they found that mosquitoes are attracted to. I don't know if you guys know about this, but I think it basically just means that they can smell humans and like to go to where humans are and then wait for them to get chomped.

But maybe, you know, before we get chomped, guys, and then you'd be more useful malaria control. Yeah, they'd be better malaria control, but they would not smell nearly as sexy. Yes. There wouldn't be blood in the mosquitoes that they were eating. So there's the vampire jumping spider. Yeah, that's awesome. Vampire jumping spider. I mean, to evolve that,

like to need to eat, there just must be so many mosquitoes for so long. For there to be a spider that preys exclusively on it? I'm sure they eat other things. No, they eat other little bugs and stuff. They have a very strong preference for mosquitoes from what I can tell, though.

Wild. Yeah, to be evolved to be like, there's my little perfume mosquito flying around. I need to eat that guy. Yeah, but not the other one. I won't eat the male because he's just full of nectar. Yeah, boring. Yeah, you want the blood-filled water balloon sack, not the nectar flying around.

Yeah, they don't care whether or not there's blood in the mosquito. That is their second thing that they look for. Their first preference is antenna. Yeah. The second place preference was big old blood belly. But if they had fuzzy antenna, I think it was kind of like, meh, I'm not going to mess with that. Right. Because that was just like, they're not going to have blood in them.

I can tell. I mean, it's wild because these things are tiny. It's very hard to I'm not going to mess with that. Right. Because that was just like, they're not going to have blood in them. I can tell. I mean, it's wild because these things are tiny. It's very hard to tell a male mosquito from a female mosquito. Yeah. The spiders are also extremely tiny. They're like the tiny little cute kinds, like that YouTube spider, you know, like Arthur or Luther or whatever his name is. I think his name is Lucas. Yeah.

They're like that guy. They look really cute. And they're red, I think, too, like a vampire would be if it was a spider, you know? Oh, okay. But do they go out in the daytime? Probably, yeah. If I shoved a steak through its heart, would it die? Absolutely.

Does it live forever? I don't know. Science is still out. Oh, my gosh. You guys made it hard for me this week. Those are both great TikToks. Just do them both. I mean, I guess I could.

Well, by the time my TikTok comes out, it will be closer to Halloween. So there is, well, it's not that close to Halloween though. I'm going to give it to you both. Yes. Oh. It's a tie. It's a tie. It's two wins.

All right. Now it's time to ask the science couch. We've got a listener question for our couch of finely honed scientific minds. It's from AJ in subspace. Andrew T, her and many other people all asked this question. Why can my partner forget bug spray, go on a hike and be totally fine, but I can't take the trash out without getting eaten alive? Sari, is there a thing that makes some people a better

attractant of mosquitoes than others? Do they just have stinky socks? So stinky socks might be a part of it. I didn't look into that one too deeply, so I'm glad Sam mentioned it. But your stink in general affects it quite a bit. So the carbon dioxide that you breathe out, specifically in bursts, that has been found to attract mosquitoes. So I just need to like slowly leak carbon dioxide instead of breathing? Yes. Instead of breathing, like poke a hole in your lungs and stick a straw in there

and just slowly breathe in and out. That's not actual medical advice, please. Don't say Siri from SciShow Changes told me to do this and and so the things that mosquitoes use to sense carbon dioxide are a combination of olfactory sensory neurons um and the hairs on the antenna and their mouth parts so apparently uh there are hairs on the mouth parts too called sensily yeah and they're specifically attuned to, besides carbon dioxide, other volatile organic compounds, which are just organic molecules, so carbon-containing molecules that are carried up as vapor into the air. So, for example, studies have shown that they are specifically attuned to lactic acid content. We all produce lactic acid to some degree, like when you're exercising within your muscles, but some people excrete it more on their skin and waft it into the air. And so mosquitoes might be like, that person seems yummy. And besides that, there are also some people, I think it's

like two thirds to one third of people who secrete proteins related to their blood type specifically. So like from the outside, you can sense a molecule that will let you know what blood type is moving through your veins. And so there's some research that says that type O, which is the one with no markers on the outside of the blood cell, seems to be the most attractive attractive but only statistically significantly relative to type a blood which has the a antigen on the outside and a lot of them are kind of up in the air but o is definitely more appealing than a so that that one is significant yeah seems seems like it okay but only in people who like secrete that chemical that is related to your blood type. Weird. That's wild.

That's a lot of different little intervening factors. Because I'd always a little bit assumed that people are like, they just love, because that's how we all feel. We all feel like we got the short end of the stick. But actually, there are people who got the short end of the mosquito stick, for sure. In these ways that you can't really control. Right. Like you can't really control right like you can't really control what

your skin bacteria composition is and what compounds you excrete right um the only behavioral thing that i found is that mosquitoes mostly use sensory organs like um like chemoreceptors so to detect chemicals in the environment but they also use vision to locate targets or process their environment. And throughout years and years and years of study, mosquitoes seem to be attracted to dark-colored objects that stand out in contrast from the background. So if you wear light colors,

like whites or yellows or sparkly things then they will be less likely to land on you so I guess wear like a sequined Met Gala dress yeah just like walk around like a disco ball

yeah when you're going to take out the trash put on my mosquito suit if you want to ask the Science Couch your questions, you can follow us on Twitter at SciShowTangents,

where we'll tweet out topics for upcoming episodes every week. Thank you to at GooeyHarrison, at SnapNap, and everybody else who tweeted us your questions for this episode. If you like this show and you want to help us out, it's very easy to do that. You can go to patreon.com slash SciShowTangents, become a patron and get access to Sari howling like a beagle. Yes.

You can also get other bonus. You can get our newsletter and our bonus episodes like Poopy Peepypedia and Q and Bidet. Second, you can leave us a review wherever you listen. That's super helpful. And it helps us know what you like about the show. And finally, if you want to show your love for SciShowTangents, just tell people about us. Thank you for joining us. I've been Hank Green.

I've been Sari Reilly and I've been Sam Schultz SciShow Tangents is created by all of us and produced by Caitlin Hoffmeister and Sam Schultz who edits a lot of these episodes

along with Hiroko Matsushima our social media organizer is Paola Garcia Prieto our editorial assistant is Deboki Chakravarti our sound design is by Joseph Tuna-Medish and we couldn't make any of this

without our patrons on Patreon thank you and remember the mind is not a vessel to be filled but a fire to be lighted. But one more thing. Drinking human blood straight from the tap can be a pretty hot business for a little mosquito, but they have a uniquely disgusting way to cool down.

So while feeding, mosquitoes will sometimes excrete drops of ingested blood from their anus without actually consuming any of the nutrients. These drops of blood are called pre-urine, and they can stick to the body before falling off, leaving a bit of fluid to act like sweat, where it evaporates and cools the mosquito down. Well, if they got the chance to do it, I guess why not? It's just like spritzing yourself with a little water sprayer, except it's human blood.

Coming out of your ass.