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  • I could pretty much guarantee you that you won't find anyone who doesn't really, really

  • hate mosquitoes. Like, that noise that they make when they're flying around your ears

  • is the worst thing. It's true that every organism has an important role to play in its ecosystem,

  • but from a human perspective, mosquitoes... they suck. I'm sure that you could rattle

  • off dozens of things you hate about mosquitoes, starting with their horribly itchy bites,

  • but I can think of at least three right off the top of my head.

  • Number one: there are only two basic kinds of mosquitoes. Hungry ones, and lazy ones.

  • Of the three thousand species of mosquitoes in the world, most actually don't bite humans.

  • But the ones that do are plenty annoying on their own. Female mosquitoes, first of all,

  • are the only ones that actually bite people. They need a protein found in animal blood

  • called isoleucine in order to produce eggs. So if they're going to make their month long

  • lives worthwhile, they need to stock up, and fast. As a result, lady mosquitoes spend most

  • of their brief lives in a ravenous search for blood meals, drawing blood from any vertebrate

  • they can find. The males, they don't really do anything. They live for an average of about

  • 10 days, and other than spending a couple of seconds mating, they just lay around, drinking

  • nectar from flowers and probably watching football or something.

  • Reason number two to hate mosquitoes: They're total discriminatory jerks. If you've ever

  • suspected that mosquitoes have been picking on you while leaving other people alone, you

  • were probably onto something. Mosquitoes actually target, like profile you might say, certain

  • kinds of people when they are looking for a blood meal. You might have heard that mosquitoes

  • are attracted to carbon dioxide and body heat, and that is true. Mosquitoes figure if you

  • are exhaling and you have a pulse, then you probably are a thing that has blood. But some

  • of us are hotter and exhale more than others. So studies have found that pregnant women

  • for example, tend to be singled out by mosquitoes because of their elevated body temperate.

  • And obese people have been found to suffer more bites because larger people simply produce

  • more CO2. Though mosquitoes can also detect a whole range of chemical compounds coming

  • out of us that we're not even aware of, like lactic acid, which we produce by metabolizing

  • milk, and octenol, a type of alcohol we secrete after eating certain kinds of fatty acids.

  • But the craziest way mosquitoes discriminate is based on our blood type. We each have a

  • blood type determined by a chemical marker, called an antigen, that forms on our red blood

  • cells. But some of us, for genetic reasons, actually have those blood type antigens circulating

  • through our bodies, and we secrete them through our skin and in all of our bodily fluids.

  • About 80% of us are these so called "secretors", and if you're one of them, that means that

  • mosquitoes can not only smell your blood from far away, they can actually tell what type

  • you are. Research has repeatedly shown that mosquitoes bite secretors more often than

  • non-secretors, and for some reason, they also prefer people with the "O" blood type, like

  • me. If that isn't discriminatory, I don't know what is.

  • But the biggest reason mosquitoes suck, is simply because they kill more people than

  • any other animal on earth. Because of their blood sucking habits and plentifulness, mosquitoes

  • are the most effective vectors, or carriers of disease, in the world. Every year, 30,000

  • people die from yellow fever for example, a viral disease transmitted by the bites of

  • mosquitoes throughout Africa and the Americas. Dengue fever is on the rise in the Americas

  • thanks these little turd wads, and then there's malaria, an incurable disease caused by the

  • parasite plasmodium, and its only way of getting around is by mosquito. There are more than

  • 200 million cases of malaria worldwide, and every year more than 600,000 people die from

  • it, the vast majority of its victims in Africa. It's estimated that more than one million

  • people die every year from all the diseases carried by mosquitoes. And if you want to

  • do something about it, then visit our friends at malarianomore.org. Explore the science,

  • get the latest news, and find out how you can literally decrease world suck by fighting

  • the spread of mosquito-born diseases

  • Thanks for checking them out, and thanks for watching this SciShow Dose. If you want to

  • keep getting smarter with us, don't forget to go to youtube.com/SciShow and subscribe.

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B1 中級

蚊が吸う3つの理由 (3 Reasons Mosquitoes Suck)

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    pjl0602 に公開 2021 年 01 月 14 日
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