Here's a vexing question asked at picnics and beach parties everywhere: "Why do bug
bites itch?"
And the answer is: They don't.
Bug bites don't itch at all, sometimes you don't even feel them, and that's pretty amazing
because what goes on under your skin when a bug bites you is horrifying.
Alright, some insects, like certain kinds of ants, are venomous so their bites can itch
because their venom contains formic acid, which can irritate and blister the skin.
But let's talk about Nematocera, the suborder of insects that includes black flies and mosquitoes.
These bugs have a long bendable proboscis that they stick into you to drink your blood.
The proboscis is made up of six different mouth parts.
First you got the mandibles which are hooked and the two maxillae which are serrated like
steak knives.
These sharp bits go as deep as they can to make an opening for the other two mouth parts
to pass through -- the labrum and the hypopharynx.
Those are both long, hollow, flexible tubes and they wriggle around inside of you like
a worm while the bug probes around for blood vessels.
Once it finds one, blood gets sucked up through the labrum, and saliva is ejected down through
the hypopharynx.
That saliva is an anti-coagulant; it stops your blood from clotting inside the bug's
proboscis so that it can keep drinking.
It is also the main vector for diseases that are transmitted by mosquitoes like Malaria
and West Nile Virus.
And it has one other awesome property: you are probably allergic to it, and when you're
allergic to something your body produces histamine, the protein that triggers inflammation and
widens your capillaries to allow white blood cells to pass through them so that they can
fight foreign invaders.
So, it's the histamine that makes you swell up and itch when you get a bug bite, just
like it makes your eyes and nose itch during pollen season.
We're not even sure why histamine needs to make you itchy in order to do its job.
It might just be your body's way of telling you that something's wrong with your skin.
But I'm pretty sure we all wish it would stop.
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