B2 Upper Intermediate English 6:24 648 palavras Animation

Why is it so hard to get rid of bed bugs? - Gale E. Ridge

TED-Ed · 295,341 visualizações · Added há 1 hora

Learning Stats

B2

Nível CEFR

648

Total Words

398

Unique Words

6/10

Difficulty

Vocabulary Diversity 61%

Legendas (80 segments)

Download
00:07

In 1834, the British Royal Navy ship, the Chanticleer,

00:13

was dealing with a terrible cockroach infestation.

00:17

The ship's surgeon, however, wrote enthusiastically about the stowaways,

00:23

describing them as a “most valuable insect.”

00:27

Their shining characteristic?

00:29

Devouring every bedbug on board.

00:33

Bedbugs have tormented humans for millennia,

00:37

so detested that their mere mention can make hearts race and arms itch.

00:43

So why are these unwelcomed houseguests so difficult to defeat?

00:50

There are approximately 100 species of bedbugs.

00:54

Thankfully, only three feed on humans, all of which are chestnut brown,

01:01

half a centimeter long, and incredibly flat—

01:04

as long as they haven’t eaten recently.

01:07

To find their next blood meal,

01:10

bedbugs follow the biological signals our bodies release,

01:15

such as carbon dioxide, odor, and body heat.

01:19

Once located, they use their straw-like mouthparts

01:23

to inject a cocktail of proteins that dilate blood vessels for easier feeding,

01:30

along with an anesthetic to block any pain that might give them away.

01:36

These compounds and other foreign proteins are what can trigger our immune response.

01:43

While some people’s bodies don’t react to these bites,

01:47

others develop itchy, red lesions that can stick around for several weeks.

01:53

And these bites can appear anywhere on the body—

01:57

it’s a myth that they always appear in neat rows or sets of three.

02:02

While they're not considered social insects like bees or ants,

02:07

bedbugs cooperate in fascinating ways.

02:11

They huddle together in piles, called refugia,

02:15

stacking their flat bodies within wall cracks or furniture,

02:20

which is thought to help them preserve precious moisture and energy reserves.

02:25

They release chemical signals, known as pheromones,

02:29

to alert each other to threats.

02:31

And their feces are rich in volatile compounds

02:35

that help guide feeding bedbugs back to the safety of the refugia in the dark.

02:42

Once a colony is established, it has tremendous staying power.

02:47

Bedbugs can go weeks or months without a meal.

02:52

If they find themselves in a particularly cool environment,

02:56

they can enter a dormant state and survive over a year without feeding.

03:02

While bedbugs can easily move around,

03:05

they usually stay within 20 feet

03:08

of where their human host is regularly sitting or sleeping.

03:13

So new infestations are most often the result of humans

03:18

accidentally transporting bugs via furniture, clothing, or other items.

03:24

Throughout human history,

03:26

we've tried almost everything to prevent these itchy invasions.

03:32

In Eastern Europe, for example, people used bean leaves,

03:36

which can trap bedbugs in their tiny, hooked hairs.

03:41

Another common trick was running lit candles along bed frames

03:46

to burn any hiding insects.

03:49

While these methods were occasionally effective,

03:52

bedbugs continued to thrive.

03:55

And in the early 1900s,

03:57

as central heating made homes more livable to humans and bugs year-round,

04:04

populations hit unprecedented heights.

04:07

But this bedbug renaissance was short lived.

04:11

In the 1940s, the pest faced an existential threat

04:16

in the powerful insecticide called dichloro-diphenyl-trichloroethane.

04:22

Also known as DDT, this neurotoxin disrupts insects’ nervous systems,

04:29

causing spasms and death.

04:31

For decades, DDT was used across the globe to control agricultural pests

04:38

and combat insect-borne diseases.

04:41

However, in the 1970s,

04:44

scientists realized DDT had accumulated to dangerous levels in the environment,

04:50

potentially putting human health at risk.

04:53

Many countries began banning DDT,

04:56

but not before it had rid the world almost entirely of bedbugs.

05:01

Almost.

05:03

After decades of quiet comfort, bedbugs reemerged in the early 2000s,

05:09

shepherded by fast-moving international trade.

05:13

Many of these insects have since become pesticide resistant,

05:18

developing traits like thicker exoskeletons,

05:21

and the enhanced ability to break down insecticide toxins in their bodies.

05:27

Thankfully, we still have options.

05:30

People can utilize high heat,

05:32

as most bedbugs and their eggs can’t survive temperatures above 45° Celsius.

05:39

And despite their adaptations,

05:42

bedbugs remain vulnerable to the suction of a vacuum cleaner.

05:47

While simple, these tools warrant some gratitude.

05:51

After all, unlike naval ships of the past,

05:55

we no longer rely on the services of our other age-old nemesis,

06:00

the cockroach.

Key Vocabulary (50)

to A1 preposition

toward

"Go to school."

of A1 preposition

belonging

"Cup of tea."

and A1 conjunction

also

"You and me."

in A1 preposition

inside

"In the house."

that A1 determiner

specific

"That book."

for A1 preposition

Used to show who is intended to have or use something, or to explain the purpose or reason for an action. It is also frequently used to indicate a specific duration of time.

on A1 preposition

A preposition used to indicate that something is in a position above and supported by a surface. It is also used to indicate a specific day or date, or to show that a device is functioning.

with A1 preposition

A preposition used to indicate that people or things are together, in the same place, or performing an action together. It can also describe the instrument used to perform an action or a characteristic that someone or something has.

as A1 conjunction

A conjunction used to compare two things that are equal in some way. It is most commonly used in the pattern 'as + adjective/adverb + as' to show similarity.

they A1 pronoun

A third-person plural pronoun used to refer to two or more people, animals, or things previously mentioned. It is also commonly used as a singular pronoun to refer to a person whose gender is unknown or to someone who identifies as non-binary.

we A1 pronoun

The word 'we' is a first-person plural pronoun used to refer to the speaker and one or more other people collectively. It is used as the subject of a sentence or clause.

or A1 conjunction

A coordinating conjunction used to connect two or more possibilities or alternatives. it indicates that only one of the options is likely, required, or true.

all A1 determiner

Used to refer to the whole quantity or amount of something, or to every member of a group. It indicates that nothing has been left out from the total being discussed.

their A1 pronoun

A possessive determiner used to show that something belongs to or is associated with two or more people or things previously mentioned. It is also commonly used as a singular possessive when a person's gender is unknown or to be gender-neutral.

so A1 adverb

An adverb used to emphasize the quality, intensity, or extent of an adjective or another adverb. It indicates that something is very or extremely high in degree.

Sign up to unlock full features

Track progress, save vocabulary, and practice exercises

Description

Dig into how bed bugs establish a colony in your home, and find out what makes it so hard to prevent these itchy invasions. -- Bed bugs have tormented humans for millennia, so detested that...

Categorias

Science History Nature

TED-Ed