The loathsome, lethal mosquito - Rose Eveleth

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Everyone hates mosquitoes. Besides the annoying buzzing and biting, mosquito-borne diseases like malaria kill over a million people each year (plus horses, dogs and cats). And over the past 100 million years, they've gotten good at their job -- sucking up to three times their weight in blood, totally undetected. So shouldn't we just get rid of them? Rose Eveleth shares why scientists aren't sure.

Lesson by Rose Eveleth, animation by Karrot Animation.

What's the worst bug on the planet?

You might vote for the horsefly

or perhaps the wasp,

but for many people,

the worst offender is by far the mosquito.

The buzzing,

the biting,

the itching,

the mosquito is one of the most commonly detested

pests in the world.

In Alaska, swarms of mosquitoes can get so thick

that they actually asphyxiate caribou.

And mosquito-borne diseases kill

millions of people every year.

The scourge that is the mosquito isn't new.

Mosquitoes have been around

for over a hundred million years

and over that time have coevolved

with all sorts of species,

including our own.

They are actually thousands of species

of mosquitoes in the world,

but they all share one insidious quality:

they suck blood

and they're really, really good at sucking blood.

Here's how they do it.

After landing, a mosquito will slather

some saliva onto the victim's skin,

which works like an antiseptic,

numbing the spot so we don't notice their attack.

This is what causes the itchy, red bumps, by the way.

Then the bug will use its serrated mandibles

to carve a little hole in your skin,

allowing it to probe around

with its proboscis,

searching for a blood vessel.

When it hits ones,

the lucky parasite can suck

two to three times its weight in blood.

Turns out we don't really like that too much.

In fact, humans hate mosquitoes so much

that we spend billions of dollars worldwide

to keep them away from us --

from citronella candles

to bug sprays

to heavy-duty agricultural pesticides.

But it's not just that mosquitoes are annoying,

they're also deadly.

Mosquitoes can transmit everything

from malaria

to yellow fever

to West Nile virus

to dengue.

Over a million people worldwide

die every year from mosquito-borne diseases,

and that's just people.

Horses, dogs, cats,

they can all get diseases from mosquitoes too.

So, if these bugs so dastardly,

why don't we get rid of them?

We are humans afterall,

and we're pretty good at getting rid of species.

Well, it's not quite so simple.

Getting rid of the mosquito

removes a food source

for lots of organisms

like frogs and fish and birds.

Without them, plants would lose a pollinator.

But some scientists say

that mosquitoes aren't actually all that important.

If we got rid of them, they argue,

another species would simply take their place

and we'd probably have far fewer deaths from malaria.

The problem is

that nobody knows what would happen

if we killed off all the mosquitoes.

Something better may take their spot

or perhaps something even worse.

The question is,

are we willing to take that risk?