Listen in English - Mosquito Bites

Directions

REVIEW the vocabulary / background.
WATCH the video.
ANSWER the questions.
CHECK your answers. (Show Answers)

Vocabulary

vulnerable [adj] - easy to be infected or hurt by something
motivated [adj] - have a strong reason or desire to do something
hatch [v] - the opening of an egg to produce babies
a proboscis [n] - the long nose of an animal
a sheath [n] - a long hollow cover that protects something inside
saw [v] - cut with a blade that has teeth
barely [adv] - almost nothing
exude [v] - give, discharge
a straw [n] - a thin hollow tube used to suck liquid
a gut [n] - the stomach of an animal
free up [phv] - create more space or time by removing something
red blood cells [n] - part of the blood
stuff [v] - pack, put a lot of something into
spit [v] - eject saliva (water) from the mouth
saliva [n] - water from the mouth
itchy [adj] - the feeling after being bitten by a mosquito
parasite [n] - an organism that lives in a host organism and benefits by taking nutrients from the host
a parting gift [exp] - a gift that you give when you leave (part)
hitching a ride [exp] - getting a ride somewhere for free
welts [n] - a red, swollen mark left on skin after being bitten by a mosquito
larvae [n] - baby insects
rain gutters [n] - shallow troughs at the edge of a roof for carrying off rainwater

[n] - noun, [v] - verb, [phv] - phrasal verb, [adj] - adjective, [exp] - expression

Questions

The mosquito is the deadliest animal in the world?
True
False
Mosquitoes kill millions of people every year.
True
False
Children and pregnant women are mostly immune to mosquito bites.
True
False
Only male mosquitoes bite people.
True
False
Female mosquitoes need blood to produce eggs.
True
False
Mosquitoes need large pools of water to hatch their eggs.
True
False
A protective sheath protects the needles inside a mosquito's proboscis.
True
False
Mosquitoes have six needles inside their proboscis.
True
False
Two of the needles hold the skin apart.
True
False
Two of the needles suck up blood from blood vessels.
True
False
Mosquitoes separate water from our blood and squeeze it out.
True
False
Mosquitoes spit a chemical into our skin to make our blood flow more easily.
True
False
Mosquito bites are itchy because of the chemical that mosquitoes spit into our skin.
True
False
Mosquitoes purposely infect humans with viruses and parasites.
True
False

Script

This is the deadliest animal in the world. Mosquitoes kill hundreds of thousands of people each year. The most vulnerable people: children, pregnant women... No other bite kills more humans or makes more of us sick.

So what makes a mosquito’s bite so effective? For starters, they’re motivated. Only females bite us. They need blood to make eggs and a pool of water for their babies to hatch in. Even a piece of trash can hold enough.

At first glance, it looks simple. This mosquito digging her proboscis into us. But the tools she’s using here are sophisticated. First, a protective sheath retracts. See it bending back?

If you look at a mosquito’s head under a microscope, you can see what that sheath protects. And inside, there are six needles!

Two of them have tiny teeth. She uses those to saw through the skin. They’re so sharp you can barely feel her pushing.

These other two needles hold the tissues apart while she works.

From under the skin, you can see her probing, looking for a blood vessel. Receptors on the tip of one of her other needles pick up on chemicals that our blood vessels exude naturally and guide her to it. Then she uses this same needle like a straw.

As her gut fills up, she separates water from the blood and squeezes it out. See that drop? That frees up space to stuff herself with more nutritious red blood cells

With another needle, she spits chemicals into us. They get our blood flowing more easily, and give us itchy welts afterwards.

And sometimes, before she pries herself away, she leaves a parting gift in her saliva: a virus or a parasite that can sicken or kill us. There’s nothing in it for her. The viruses and parasites are just hitching a ride. But this is what makes mortal enemies out of us and mosquitoes.

They take our blood. Sometimes we take theirs. But often, not soon enough.

Good. You’re still there. These are the larvae of Culex pipiens, a.k.a. the common house mosquito here in California. Gross, right? Well, you can avoid them by emptying your rain gutters. Pet water dishes too.

While you're at it, subscribe! We have so many more science videos coming your way. See you next time!

Mosquito Bites

Published: 11.11.2019

Level 4 | Time: 3:17

Accent: American

Source: YouTube

Directions

Vocabulary

Questions

Script