The loathsome, lethal mosquito - Rose Eveleth

12,472,532 views ・ 2013-12-02

TED-Ed


Please double-click on the English subtitles below to play the video.

00:06
What's the worst bug on the planet?
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You might vote for the horsefly or perhaps the wasp,
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but for many people,
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the worst offender is by far the mosquito.
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The buzzing, the biting,
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the itching,
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the mosquito is one of the most commonly detested pests in the world.
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In Alaska, swarms of mosquitos can get so thick
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that they actually asphyxiate caribou.
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And mosquito-borne diseases kill millions of people every year.
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The scourge that is the mosquito isn't new.
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Mosquitoes have been around for over a hundred million years
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and over that time have coevolved with all sorts of species,
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including our own.
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There are actually thousands of species of mosquitos in the world,
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but they all share one insidious quality:
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they suck blood,
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and they're really, really good at sucking blood.
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Here's how they do it.
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After landing, a mosquito will slather
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some saliva onto the victim's skin, which works like an antiseptic,
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numbing the spot so we don't notice their attack.
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This is what causes the itchy, red bumps, by the way.
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Then the bug will use its serrated mandibles
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to carve a little hole in your skin,
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allowing it to probe around with its proboscis,
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searching for a blood vessel.
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When it hits one, the lucky parasite can suck
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two to three times its weight in blood.
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Turns out we don't really like that too much.
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In fact, humans hate mosquitos so much
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that we spend billions of dollars worldwide
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to keep them away from us --
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from citronella candles
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to bug sprays to heavy-duty agricultural pesticides.
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But it's not just that mosquitos are annoying,
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they're also deadly.
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Mosquitos can transmit everything from malaria to yellow fever
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to West Nile virus to dengue.
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Over a million people worldwide
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die every year from mosquito-borne diseases,
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and that's just people.
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Horses, dogs, cats,
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they can all get diseases from mosquitoes too.
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So, if these bugs are so dastardly, why don't we just get rid of them?
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We are humans after all,
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and we're pretty good at getting rid of species.
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Well, it's not quite so simple.
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Getting rid of the mosquito removes a food source
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for lots of organisms, like frogs and fish and birds.
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Without them, plants would lose a pollinator.
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But some scientists say
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that mosquitos aren't actually all that important.
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If we got rid of them, they argue,
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another species would simply take their place
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and we'd probably have far fewer deaths from malaria.
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The problem is that nobody knows what would happen
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if we killed off all the mosquitos.
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Something better might take their spot
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or perhaps something even worse.
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The question is, are we willing to take that risk?
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(Buzzing)
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