the most dangerous animal on earth isn't
the shark the lion or even the
hippopotamus it's so small in fact that
it could sit on the tip of this pencil
biologists estimate that it is killed
nearly half of all humans ever born and
today accounts for more than 45 million
years of lost human life annually
mosquitoes
a mosquito is any of more than 3000
species of tiny annoying flies and a
family coolies today among those species
that feed on blood the vampire action is
carried out solely by the females who
require the proteins and nutrients in
animal blood in order to lay their eggs
blood sucking mosquito species have very
discerning palates when it comes to
which species they feed on mosquitoes
that prefer birds for instance may not
suck our blood only a few hundred
species are actually known to poke those
tiny holes in humans among humans
mosquitoes are known to be more
attracted to some of us than others I
recommend making friends with one of
these people and inviting them to your
next barbecue as a natural bug decoy and
if you already get invited to a lot of
barbecues it's probably you mosquitoes
can detect exhaled co2 from over a
hundred feet away so heavy breathers
watch out
they also shows certain preferences for
blood types pregnant women and
particular populations of skin bacteria
body odor chemicals like octanol lactic
acid and this one don't you laughs our
skier magnets as well as ethanol that's
been secreted through our skin after
drinking while we used to think that
insect repellents like DEET worked by
blocking a mosquitos smell receptors new
research suggests that the bugs just
really really hate the smell although we
call them bites mosquitoes actually poke
evolution has molded the mouth parts of
the ectoparasites into highly
specialized face daggers and closed
within a sheath called the labium and as
they enter the skin their unsheath than
the flexible mandible seeks out of blood
vessels oh my god
what is it doing oh no no no god aah
make it stop
when the mosquito finally taps into
sanguine sustenance it uses its tongue
like labrum to slurp up a belly full of
blood our immune system reacts to the
foreign proteins in their saliva
resulting in red bumps on your skin so
you really only have yourself to blame
for the itching but mosquitoes didn't
become the largest killer of humans
thanks to scratching ourselves to death
in fact it's not really mosquitoes that
do all that killing the actual culprits
aren't even
smaller meat Plasmodium falciparum the
most common cause of deadly malaria this
microscopic protozoan parasite swims its
way into our bloodstream by the
mosquitoes salivary glands where it
infects the liver and red blood cells
and often results in a deadly fever and
when another mosquito feeds on malaria
infected blood the parasite can sexually
reproduce mutate and spread and kill and
all sorts of bad stuff today malaria
kills about a million people per year
and sickens half a billion so what can
we do about it
we do see signs of an ongoing
evolutionary arms race against malaria
inside our own genomes people who carry
one copy of the sickle cell gene
mutation a trait common in tropical
regions like sub-saharan Africa show
resistance to the disease likely by
disrupting the parasites blood cell life
cycle yet malaria persists insecticides
and other chemicals are effective but
they often harm the environment or wipe
out beneficial insects along with the
bad anti-malaria drugs like artemisinin
while cheap and effective carry a risk
of resistance and they're completely
ineffective against viral mosquito-borne
illnesses like dengue fever so why don't
we just get rid of mosquitos is such a
thing even possible yes it is maybe
Oxford University biologists have
created genetically engineered male
mosquitos with a mutation that kills a
hundred percent of their offspring and
when those males are released into the
wild they mate with females but all the
eggs are duds and in those places and
mind you this has actually been done
dengue carrying swarms have plummeted I
mean this works for us at least in some
ecosystems mosquitoes are important
pollinators or food sources for other
organisms eliminating mosquitoes even
just the specific disease carrying
species might lead to negative effects
that we can't even predict but this
human health outweigh those
environmental concerns is expensive
genetic engineering better than say
net over your bed could it be like
science writer David Kwan says that
mosquitoes are in some ways defending
the world's wilderness from even wider
human invasion with their tiny little
swords and their diseases guarding the
jungle from us humans these are
difficult questions they forced us to
put the health of our own species at
odds with another's and the answers
aren't simple I don't know what you
think I put some links down in the
description to check out so let's talk
about it in the comments what the heck
should we do about mosquitoes whatever
the answer we've got science on our side
and I think that's a good thing stay
curious our noses can detect up to a
trillion different sense and many of
them are tied deeply to memories and
emotions like grandma's house or your
first dog or the smell of rain storm
winds carry an orchestra separate smells
but the earthy odour that precedes a
storm can be traced to three chemical
sources