[Intro]
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.