What really happens when a mosquito bites you?

If ever, like me, you've lain awake in the dark wondering why on God’s green earth the thing hunting you has to make that infernal noise...how it found you... and why it has to itch after it bites you…well, the answers are here and they are more surprising than you've guessed.

A female Aedes mosquito

The first law of attraction

Before anything else, the mosquito hunting you has to identify you as its prey. To do so, these little aerial hunters rely on various cues given off by your own body. Carbon dioxide from your breath, heat from your body. Even the chemical messages given off by your own skin bacteria can be eaves-dropped on to pinpoint a target (check out this study here: https://www.smithsonianmag.com/science-nature/stop-mosquito-bites-silence-your-skins-bacteria-180955772/ where scientists think they've figured out a way to short circuit this process).

Once honed in on, the mosquito penetrates skin with a complex (and surprisingly flexible) proboscis made up of six separate parts or ‘stylets’. Compounds in your blood such as adenosine phosphates then provide the stimulus to keep on sucking.

Mosquito mouthparts consisting of four piercing stylets (mandibles and maxillae) on the outside and an inner sucking tube (hypopharynx and labrum)

Stealth mode?

Apparently not. While it may seem counter-intuitive for something that's trying to feed on you to make such a damn noise, actually, the reason for that irritating whine is the way in which females wings beat. An organ at the base of the wing scrapes as it flaps causing the high-pitched sound. To male mozzies, it's the sound of love, and they use the distinctive, slower beating of the female of their species to identify potential mates. In fact, they're so attuned to it they'll even chase down tuning forks vibrating at the same pitch!

The structure on a mozzy's wing responsible for that damn noise!

Here’s the rub…

Okay, but why does it also have to itch? The answer to that lies with your body’s own immune response. When a mosquito bites, she injects saliva containing an anticoagulant compound in order to feast more efficiently. Like any foreign body entering your own, this causes a histamine reaction, similar to what happens when pollen enters your sinuses. The result is a raised, irritating, itchy bite and a whole lot less sleep.

Your body’s own immune response is what causes the irritating itchiness associated with the bite.

What to do, what to do?

Well, scientifically, it's been shown that certain people are just more attractive to mozzies so you may be in that unlucky band. Whether you produce more carbon dioxide or more lactic acid or some other compound, you may simply have lost the genetic lottery for natural insect repellent. Lactic acid (which also crops up in sweat when you exercise) is definitely an attractant and substances such as lotions or perfumes may also play a role. Weirdly enough, bacteria from certain types of cheese has been found to also play a role, so maybe, you know, wash your feet properly.

And if keeping cool and clean doesn't work, well, hard as it may be, just stop and think for a second about the perfect evolution involved in making a tiny, blood-seeking torpedo while you're lying awake cursing the whining dark.

Happy Steeming People,
The Wise Fox

Sources:
https://www.smithsonianmag.com/science-nature/stop-mosquito-bites-silence-your-skins-bacteria-180955772/
https://articles.mercola.com/sites/articles/archive/2015/08/08/why-mosquitoes-bite.aspx
https://theconversation.com/health-check-why-mosquitoes-seem-to-bite-some-people-more-36425
https://www.mnn.com/health/fitness-well-being/stories/why-do-mosquito-bites-itch
http://phenomena.nationalgeographic.com/2013/08/06/heres-what-happens-inside-you-when-a-mosquito-bites/
http://www.mosquitoreviews.com/mosquitoes-buzz-ears.html

Images: wikimedia commons
Image 3: http://www.mosquitoreviews.com/mosquitoes-buzz-ears.html
Image 4: https://www.mnn.com/health/fitness-well-being/stories/why-do-mosquito-bites-itch