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ELI5 Yahaaa

It is not the bite, it is you

Why Does a Mosquito Bite Itch?

A mosquito bite does not hurt going in. The itch afterwards is your own body reacting.

1 It landswithout younoticing2 A thin tubeslides in andspit goes down3 Your bodyreacts — and ititches
The bite is painless. The itch is the argument afterwards.

  1. Step 1 of 5

    Only the females bite.

    The male Drinks nectar, bitesnothingThe female Needs blood to makeeggs

    Male mosquitoes drink flower nectar and never touch anyone. A female needs the protein in blood to make her eggs, so blood is not food for her — it is building material.

  2. Step 2 of 5

    It spits before it drinks.

    1 Saliva goesdown first2 The blood iskept runny3 Now it candrink through ahair-thin tube

    Blood is designed to clot the moment it leaks, which would block a tube that thin. So the mosquito first pumps down saliva that stops the clotting and widens the vessel, then drinks.

  3. Step 3 of 5

    The itch is your alarm system.

    1 Foreign salivais left behind2 The body raisesthe alarm3 Vessels leak —bump and itch

    Your body spots that foreign saliva and releases histamine. That makes the tiny vessels leak, which is the bump, and it fires the nerves that mean 'itch'. The mosquito left long ago.

  4. Step 4 of 5

    It finds you by your breath.

    Breath, warmth andskin smell It follows thetrail in

    From far off it follows the carbon dioxide you breathe out. Closer in it switches to body heat and the smell of your skin — which is why some people really do get bitten more than others.

  5. Step 5 of 5

    It starts life in water.

    Eggs laid on still water The younghang underthe surface They breathe through a snorkel An adultflies off

    Eggs are laid on standing water, and the young live there hanging under the surface, breathing through a tube. Tip out the bucket and the saucer under the plant pot, and there are no mosquitoes.

    A mosquito is the deadliest animal on Earth, not because of the bite but because of the diseases some kinds carry from person to person.

The short version

A mosquito spits to stop your blood clotting, and the itch is your own body reacting to that spit.

Try it yourself

Look for standing water around your home after rain — a bucket, a tray, a blocked gutter. Emptying it removes a whole generation.

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