Nova (1974–…): Season 48, Episode 23 - Butterfly Blueprints - full transcript

Scientists are discovering the secrets of butterflies and using that knowledge to improve technology.

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In the science of
the very small,

some ingenious inventors
are inspiring materials

with wondrous properties.

Sensitive to climate change.

They can act as a sentinel for
our interaction with the planet.

Brilliant color without paint.

What we see here is a close-up.

We see that the blue comes
from the background scales.

Protection from hazardous
chemicals and bacteria.

The word
"contaminated" on the glove

will turn from blue to red



when you touch a surface
that is contaminated.

Even an unsinkable metal.

As our ocean level

continue to go up,

in the future,

a lot of city will have
to be built on top of the ocean.

All thanks to the millions of
years of evolution

packed into the remarkable
world of butterflies and moths.

There's many problems that
humans haven't solved

that butterflies and moths
already have.

"Butterfly Blueprints,"
right now, on "NOVA."

♪♪

♪♪

Butterflies and moths.



Graceful and beautiful.

Their delicate wings seem
barely suitable for flight.

In spring and summer,
they appear in our skies,

flitting

and floating.

Their dazzling
colors and patterns

are among the most amazing
in the animal kingdom.

Some estimates put
the number of species

around 160,000,

and they thrive in nearly

every nook and cranny
of our planet.

If you go to
the northern latitudes,

you'll find butterflies.

If you go to the desert,
you'll find butterflies.

If you go to the rainforest,

you'll find butterflies
and moths.

Their variety and beauty

are testimony to
the power of evolution,

as are their
countless hidden features...

Some visible only with
the most powerful microscopes.

Today,
scientists around the world

are studying
these natural treasures.

Gorgeous.

Discovering secrets that
can be adapted

and applied to make
our world more sustainable.

They're so beautiful,

but we can learn a lot
by studying them.

As champions of evolution,

they've been at it for
tens of millions of years.

Butterflies emerged
around the same time as

flowering plants.

Throughout their long history,

they have diversified
and developed

amazing adaptations, like

powerful poisons, silk thread,

stationary flight,
transparent materials,

temperature regulation,

astonishing colors and patterns,

and defenses
against bacterial infections.

♪♪

They have so much to teach us.

But today, many species
are in danger of

extinction,
threatened by a warming world.

♪♪

And if we can
find ways to save them,

it's becoming clear that
we'll also be helping ourselves.

In North America,
an iconic species

is particularly vulnerable
to climate change

and habitat loss.

Delbert André Green Il,

a researcher at the University
of Michigan, Ann Arbor,

studies the complex life cycle
of the monarch butterfly.

One of the questions that
I get asked most often is,

why should we expend
so much resources

into this one
particular species,

this one butterfly?

What makes it so special?

What really
makes monarchs special is,

they can act as a sentinel

for our interaction with
the planet.

Their migration
covers an entire continent.

♪♪

That migration begins each fall

when millions of monarchs
take off from Canada

and the Northern United States
and head for Mexico,

where they remain
until the following spring.

It's a 3,000-mile
test of endurance

that lasts up to two months.

If we look at

this population size by
counting the number of monarchs

that make it to Mexico,

that number has been
declining pretty consistently

over the past two decades.

And that's,
we still consider worrisome.

Delbert believes the decline

can be used to gauge the level
of environmental change

that the butterflies encounter
on their journey.

If there aren't enough
nectaring flowers

along the migration route,

then monarchs
won't be able to power

the entire flight.

That's also going to be
impacted by climate

and by how we
change the landscape

through our own development or
agricultural practices.

In Mexico,

monarchs that survive the
journey gather together,

forming spectacular
wreaths of living color.

Snuggled close together,

they fall into a kind of
hibernation called diapause.

As their metabolism slows,
they suspend activity,

storing their energy
until the spring returns.

But during this time,
they are still vulnerable.

Diapause conditions have to be

almost perfect in order for them

to be able to survive
the winter.

If temperatures are changing
at the overwintering site,

then that's going to lead to

kind of this disturbance in,
potentially, diapause timing.

♪♪

During their diapause,

monarchs endure a very
sensitive and crucial time.

Diapause allows them to

slowly burn through
their fat stores.

So if it ends too early,
they're going to start

burning through their
fat stores more quickly,

and they're going to be
more susceptible to infection,

which will potentially
increase mortality

at the overwintering sites

before spring arrives,

and the temperatures
become warm enough

such that they can mate

and start to
fly back northwards.

By monitoring monarch
populations,

scientists can gain insight
into how a warming climate

can disrupt ecosystems,

threatening not only monarchs,
but other species, as well.

♪♪

Butterflies are
giving scientists like Delbert

a window into
our changing climate.

But that's only the
beginning of what studies

of these remarkable creatures
are revealing...

Particularly about
the structure of materials

at the nanoscopic scale.

Researchers
have been inspired by

incredible nanoscopic structures

in the wings and bodies
of butterflies,

enabling the creation
of innovative technologies

that may one day save lives

and even help combat
climate change.

Butterflies and moths have many
aspects of their morphology,

of their physiology,
that we could use

for bio-inspired design,
for sure.

I mean, there's many things,

many problems that humans
haven't solved

that butterflies
and moths already have.

♪♪

The use of butterfly and moth
features dates back

at least 5,000 years,

when the species
known as Bombyx mori

was first domesticated in China

for its ability to produce

a phenomenally resilient
and versatile material...

Silk.

♪♪

Because of
the importance of silk

to the Chinese imperial court,

the means of producing it
was a heavily guarded secret,

and its violators were punished,
even by death.

Today, of course,
the secret is out.

The whole process
starts with the hatching

of a miniscule egg

and the birth of
a caterpillar that measures

less than an eighth of an inch.

From its earliest days,
the Bombyx caterpillar

devours an enormous quantity

of mulberry leaves, plant matter

that it will eventually
convert into silk thread.

♪♪

After about a month of feeding,

the Bombyx caterpillar
will find a branch to climb,

where it will begin
metamorphosis

into its adult form.

For the next few days,
it will tirelessly repeat

the same figure-eight movement,

while secreting
a viscous filament, the silk,

eventually spinning up to a mile

of the thread into
a protective cocoon.

♪♪

Scientists have found that
the thread is mainly comprised

of just two proteins.

♪♪

Today, a whole new chapter

is opening in the story of silk.

Researchers at
the Tufts Silklab in Boston

have isolated
one of the proteins,

called fibroin,

and have created
an innovative material.

So, we end up with a solution

that is the suspension of
the fibroin molecules in water.

Once we have the solution,

this is our magical
starting material to do,

to do many, many things.

And so, and so the key is
that you have these proteins

that are floating in water,

and you remove water
as the solvent

and you have
two proteins come together

in many, many different formats.

Then you get different outcomes
of materials.

To the scientists,

silk is an incredibly versatile,

environmentally friendly
material.

What begins as
a colorless liquid...

This gel-like solution...

Can be either
flexible and soluble

or as tough as Kevlar.

Luciana d'Amone is exploring
medical applications.

Fibroin has an advantage

over synthetic materials
like plastics

because it's compatible with
the human body.

Oh, so this is the...

net.

Net, so these are very nice.

Yeah, but as soon as I

stretch them, they are,
are breaking down.

This is going to be nice

for, like,
a Band-Aid-type application

or a reconfigurable,
so these are very, very pretty.

Yeah, the idea would be to

mix the drug together
with a solution

and then control the release

of the drug on
a higher surface area,

just stretching the net.
Yeah.

The attributes,

the functional attributes
that silk has

that, that give value to some of
the applications of the silk,

is the fact that
silk can be implanted

without an inflammatory response
in the human body.

That it can, it can be eaten,
it can be consumed.

In the lab, they are finding
that the fibroin material

can be made to
be rigid and tough

or flexible, like a film,
making it an ideal material

as an implant
in reconstructive surgery.

If you take this material
and you know that you can

mechanically shape it

with the tools
that you commonly use

in a mechanic's shop,
then what you can do is,

you can generate small screws.

The screws made of fibroin

are similar to
the metal screws currently used

to reconstruct bones.

They can also deliver
human growth factor compounds

to help bones knit together.

So these are the worlds
that come together:

the mechanical properties
and the medical properties,

in a material that integrates
with, with living tissue.

In liquid form,
the fibroin in silk

is also being combined
with chemicals that react

in the presence of

bacteriological or
viral threats.

The result is an ink
that can change color

when exposed to
dangerous substances

in the environment.

All of the inks that are here
on the tapestry react,

react to the environment,

react to the environment
around it.

And so when you,
when there is a change

in the environment around it,

they will change
color accordingly.

♪♪

This fabric is of
particular interest

for making protective gear

for workers operating
where they might be exposed

to dangerous substances.

So these types of inks
are very interesting

to turn objects into,
into sensing objects.

If you print a word
with these inks

onto the surface of
personal protection equipment,

so, like, a glove here,

that word will, will
sense the environment around it.

In this case,

the word "contaminated"
on the glove

will turn from blue to red

when you touch a surface
that is contaminated.

The caterpillar
that produces silk

is only one stage in
the butterfly's

unique life cycle.

In all, it moves through
four distinct phases:

egg,

caterpillar,

chrysalis,

and adult.

The butterfly extracts itself
from its chrysalis,

dazed and fragile...

unfolding its wings and its body

with a cloth-like rustling.

When it emerges
from its chrysalis,

the adult has been
completely transformed

into one of the most delicate
and graceful creatures

in nature.

And, of course,

the vivid and iridescent
colors and patterns

of butterfly wings are
their most striking feature...

Nowhere seen more brilliantly

than in the male
of the morpho species

of the tropical rainforest.

In flight, its wings

seem to give off blue flashes
that are hard to miss,

even in the densest forest.

Serge Berthier,
a research physicist

at the Paris Institute of
Nanosciences,

talks about the wings'
unique properties.

Each species presents a
slightly different blue

and has a slightly
different wing beat,

and then variations of colors
that we see here:

a phenomenon of iridescence

where the color varies
in flight.

It's part of
the code of communication

between males and females.

It's an impressive adaptation

to the problem of finding
a mate in the forest,

but it comes with a problem.

What is so visible
to the female butterfly

is also noticeable
to hungry birds.

The male has to find a way
to parry this,

that is, being very visible
while not getting caught

by the first predator
that comes along.

The genius of this butterfly,
like many others,

is that it does not
fly straight.

As it flits through the forest
blinking blue,

it follows an
unpredictable zig-zag path,

making it hard to track.

So, you have a dotted line

zig-zagging like that,
which makes it almost impossible

for a bird to calculate
its trajectory

and snap it up in flight.

It's the morpho's
iridescent blue

that intrigues Serge and the
other researchers the most.

They want to understand

how nature produces a color
that looks so... unnatural.

What we see here is
a close-up of this wing.

We see that the blue

comes from
the background scales.

And there are scales here that
clog the joints on top of them.

These are covering scales,
and they are transparent...

You can see through them.

The morpho uses

a very peculiar way
to generate color.

It is a structural color,

which is intrinsically different
from a pigment color.

This is in contrast to
regular pigment.

Pigment are like
granules of pigment

that are inside of the cells
that give something

a yellow or a red or a,
or a green color.

The pigment color results from

the partial reflection of
daylight.

When a pigment reflects
a red color, for instance,

it means it has absorbed
all the other colors.

But then there's this other
type of coloration

that's actually not
caused by a pigment.

The structures that produce
the color of the morpho

are visible
under the microscope.

The wings show a regular pattern
of raised surfaces,

each one just one ten-millionth
of a meter in size.

It's the size of
these structures

that produces
the wings' iridescence.

It's caused by
little bumps, or, or...

Rugosities, they call them,

or little deviations
in the smoothness

of the insect's skin.

And when light
bounces off of that,

our eyes perceive it
as being a metallic,

or shiny, or iridescent color.

The blue of the morpho's wing
is not due to pigmentation,

but is generated by the
structure of the wing itself.

When light strikes the wing
at certain angles,

its nanoscale feature
selects only

the blue frequencies,
which are reflected,

resulting in an iridescent,
metallic appearance.

♪♪

The surprising new insight
into structural color

has inspired researchers

to control light and
produce color

without chemicals or paint

in all sorts of other materials.

At the Institute of Optics
at the University of Rochester

in the United States,

Chunlei Guo has succeeded
in creating such structures.

Inspired by this
morpho butterfly,

so we actually can also
imprint some of these

tiny micro, nanostructures
onto a material surface

and give them
very unique properties.

Using an infrared laser with
very short bursts of light,

they are able to
sculpt nano-sized structures,

measured in billionths
of a meter, into metals.

This incredible method of

creating various colors
on surfaces

has not only allowed
the researchers

to reproduce the color
of the butterfly's wings,

it also enables them

to create a highly
light-absorbing material

that could be called
absolute black.

Colored metal actually
will selectively absorb

a certain range of color,
but reflect other colors

so that it give you
a certain colored appearance.

So we create this technology,
so the black metal

actually will indistinguishly
absorb

all colors of, of the spectrum,

therefore it's, appear
pitch-black.

These discoveries

have the potential to
revolutionize solar power.

Chunlei's team found that
applying these nanostructures

to a solar panel

improved its efficiency by 130%.

The nanostructures

allow the panel to absorb

almost the entire
light spectrum,

minimizing loss of energy
due to reflection.

♪♪

As well as
transforming solar power,

inspiration from butterfly wings

could lead to other innovations.

Well, I mean, butterfly
and moth wings

serve multiple purposes, right?

Primarily, they're for flight.

But then, the coloration and
patterns that are on the wings

are a signaling.

Sometimes it's
signaling to each other,

males signaling to other males,

or males signaling to females

that's the same species.

Sometimes the signal
is actually for a predator.

In nature, color
plays a vital role

in both reproduction
and survival.

♪♪

Through either pigment
or structural color,

butterfly wings

often create complex patterns

that entomologists
suspect are meant to

send signals not to mates,

but to predators.

And in some cases,

present uncanny copies of
similar colors and patterns

found in other living things.

Often, the butterflies and moths
that you see are orange

or orange, yellow, and black.

It's a signal that

these moths or butterflies
are distasteful,

and presumably
birds only have to learn

one big kind of color pattern.

Orange, black, yellow: avoid.

In the plant and animal world,

orange, yellow, and black

are sometimes associated
with poison.

And some butterflies
seem to rely on those colors

to discourage birds
from eating them.

And these two look
really similar.

These are the monarch
and the viceroy.

The monarch and the viceroy
are easy to distinguish

because the viceroy
has this additional

kind of line of dark color by
the base of its wings.

This is a distasteful
monarch butterfly

that birds learn to avoid.

And the viceroy mimics
the monarch's coloration

presumably so that
it also can be protected

and it doesn't get eaten by
birds like, like blue jays.

Butterflies use a variety of
defense mechanisms.

Although some boldly
wear the signs of toxicity,

others prefer to pass unseen.

They melt into
the surrounding colors

of their natural environment.

For example, the Greta oto,

also known as
a glasswing butterfly,

relies on a double defense:

displaying some warning colors
while most of the wing

is almost totally transparent...

A most unusual adaptation.

The wings' surfaces have
scarcely any reflectivity.

Even glass and
other human-made materials

reflect some light.

But not this butterfly wing,

which makes it extremely
interesting to scientists.

Researchers at the

Karlsruhe Institute
of Technology in Germany

are studying
the unusual properties

of transparent-type wings
like the Greta oto's.

What we see on top

are these nanostructures here,
nano pillars,

which have random heights.

And also the distance
between the nano pillars

is a little bit random.

So they're
not regularly arranged.

And this randomness is important

for the anti-reflective
properties of the butterfly.

♪♪

This is where the secret of
the high transparency lies:

the random distribution
and size of

these conical nanometric pillars

create an anti-reflective layer,

allowing light rays,
even the most grazing,

to pass through the wing

without being
dispersed or reflected.

This anti-reflective property

is interesting for
different types of applications,

like smartphones, for instance.

In the summer,
when the sun is shining,

it's hard to read
and it would be nice

to have an
anti-reflective screen.

And also for solar cells.

It would be interesting
to have less reflection

and have more collection
of the solar energy.

These researchers create
a plastic film on which

they print nanostructures
in imitation of those

in the crystalline-type wing.

Their goal is to create

anti-reflective materials
that are highly transparent.

The nanostructures of the wings

offer other properties,

such as the ability to
repel water,

known as hydrophobicity.

Staying dry is a matter of
life and death for butterflies.

Mist and rain
would quickly ground them

if they weren't waterproof.

A butterfly must not get wet.

If the wings were wet
and they touched each other,

they would stick together,
and the butterfly would die.

So a butterfly wing is
super-hydrophobic.

That is, the wing doesn't get
wet... water forms beads.

And then the beads
roll off, cleaning the wing of

all of the dust and dirt
it picks up along the way.

Thanks to its nanometric
structures,

the morpho's wing doesn't just
rid itself of water drops,

it breaks them down into
a multitude of smaller drops

that flow more easily
off the surface.

In his Rochester lab,

Chunlei Guo is exploring
possible engineering

applications for this extremely
hydrophobic material.

In one of his experiments,
he starts by laser-etching

a metallic surface with a
nanoscale pattern

inspired by the morpho wing.

He's hoping to create the same
water-repelling effect.

♪♪

When he drops water on the
surface he has created,

it is totally repelled.

The experiment is a success.

Water drops are not only
repelled,

they bounce back.

With this material,

Chunlei's team seems to have
created an unsinkable metal.

And what we did was, we actually
utilized in,

build a metallic assembly

with a super-hydrophobic
surface,

so that the hydrophobic surface,
they are facing each other.

And if you put this
metallic assembly inside water,

and because the inside of the
assembly is super-hydrophobic,

so that it will push the water
out and will prevent the water

squeezing into the
metallic assembly,

and the air trapped inside
will keep

the metallic assembly afloat.

Fabricating a ship's hull

using this design would have
an obvious benefit.

But Chunlei believes
it could also help us adapt

to climate change.

And as our ocean level
continue to

go up in the future,
a lot of city will have to be

built on top of the ocean.

And if we can deploy this
unsinkable metal

for construction of the floating
city, then the city

will never sink.

♪♪

Who could have imagined
that one day a ship...

Or even a whole city...

Might rest on
a butterfly's wing?

In California,

researchers work on combining
transparency

and the opposite of
hydrophobicity...

Extreme water absorption.

What's at stake is not
rising water, but glaucoma,

a group of eye conditions
that can cause blindness.

Radwanul Hasan Siddique

at Caltech is working to create
a tiny implant that would work

inside the eye to help detect
this devastating condition.

So, in our lab,
we make an optical implant

for continuously measure
the eye pressure

for glaucoma progression
measurement.

♪♪

Glaucoma is a condition
that damages the optic nerve,

most often caused by rising
internal pressure in the eye.

Today, an implant could provide
easy access

and constant monitoring
for a patient at risk.

But of course, anything inside
the eye needs to be transparent,

especially an
artificial implant.

Glass has around eight to ten
percent reflection.

And that reflection basically,
you can see a glare, right?

So if you see in the windows
or glass at some angle,

you can see glare because of
the reflection of the light.

But this glasswing butterfly,

although it's glass-like, but it
doesn't have any reflection,

or almost no reflection.

For Radwanul,
an implant in the eye

cannot be water-repellent
like the butterfly wing.

He needs to engineer something
different.

The implant is going to be
in the inside of your eye

in the aqueous humor,
which is a fluid.

So if it's, repels water,
then it's hard to implant,

and it won't survive there.

So in our case, we need
basically an opposite property,

which is super-hydrophilic.

♪♪

To make his implant,

Radwanul blends two chemical
compounds at very high speed.

Their combination creates
nanostructures like those of

the glasswing butterfly
out of a hydrophilic material

that patients' eyes
can tolerate.

These randomly distributed
dome-shaped nanostructures

conserve the transparent
properties of their model.

Because the gaps between them
are so narrow,

bacteria cannot get a grip
on the surface,

reducing the risk of infection.

Once we introduce
a nanostructure like the

glasswing-inspired
nanostructures on the implant,

it shows better performance,
has a better optical readout,

and also, it doesn't show
any anti-fouling,

any fouling properties, so...

Which means no tissue
are encapsulating,

no, no bacteria are sitting,
and we may take a measurement

over a year inside a rabbit eye

without seeing any kind of
fouling.

♪♪

Not all butterfly wings
are visually arresting.

The nanostructures in wings

are not only involved in color,
transparency,

or tricking predators.

Some of them serve to provide
direct metabolic benefits

for survival.

♪♪

Like all insects,
butterflies and moths

are cold-blooded.

No butterfly can take off

without a minimum of sunlight
to heat its body.

Dark-winged butterflies absorb
the heat of the sun

more readily and seem to have
an advantage over those

with lighter-colored wings.

♪♪

It might seem that
a white-winged butterfly,

like the cabbage white
butterfly,

would be operating
at a huge disadvantage.

And yet, in the early morning,

even on cloudy days,
it is one of the first arrivals

to gather nectar in
flower fields.

How does it manage it?

♪♪

At the Paris Institute
of Nanosciences,

Serge Berthier is interested in
this phenomenon.

So the white butterflies

cannot directly absorb light

through the wings
because they're white,

and reflect all the energy.

What they do when they need
to warm up is use their wings

as concentrators
before taking off.

They place themselves
facing the sun,

then open and close their wings
like this.

As it's very reflective,

it sends a lot of light,
and concentrates the light

on its back, the thorax,
where the wings'

abductor muscles are located.

So when the wings concentrate
the light,

the thorax will absorb
all this energy.

The reflective white coloration
acts as a mirror

to concentrate heat onto
the animal's body.

In the tiniest details,

Serge Berthier can verify the
way heat is sent to the thorax.

As with all scales, we see
a network of striations,

but what's particular to the
cabbage white butterfly

is that there is a network
of counter-striations,

in this direction.

And small compartments
are formed inside.

The cabbage white's scales

contain tightly packed
ovoid-shaped granules,

like eggs in a carton.

They reflect the sun's rays,
but not in all directions.

They focus the light and heat
like a magnifying glass.

The butterfly then angles
its wings in a way that sends

the heat down to its back.

This is how the butterfly
warms up.

The butterfly just has to
open and close its wings

to regulate its temperature.

In fact, it's the master
of its own temperature.

♪♪

Finding new ways to concentrate
sunlight is important

for humans, too, in the search
for cheap and efficient

replacements for fossil fuels.

In her lab at the
University of Exeter,

Katie Shanks is adapting
the cabbage white's

reflective nanostructures
to solar panels,

working to increase their output
while reducing their size.

So by looking at the wings
of the cabbage white butterfly,

we can actually
reduce the weight

a very significant amount.

So in initial studies,
we've been able to improve

the power-to-weight ratio
by 17 times,

which is, is a massive amount.

And what I'm specifically
looking at is using those

very lightweight nanostructured
wings to make our own

very compact advanced
solar panel

built into any materials.

♪♪

Today, by combining the
properties of the glasswing

and cabbage white wings,

researchers are hoping
to develop a new generation

of solar panels.

So the glasswing butterfly
would be for the surface,

the entrance aperture.

And the cabbage white butterfly

would be for the side walls,

just before the solar cells.

And overall, that means we get
this kind of

increased power output
from all the solar cells,

but not using as much
PV material.

And you can also make it

a lot smaller and lightweight,
as well.

I mean, all of the butterflies
and lots of other things

in nature have had to do this,
you know,

as, as they've developed,
they've evolved,

and they've tweaked themselves
to suit their surroundings.

And I think we're now realizing
we have to do the same

in terms of tweaking our,
you know, energy demands

and our uses and our materials
that we use to kind of make sure

we are also sustainable
and surviving,

just as the butterflies are.

♪♪

It's remarkable that butterfly
wings can offer protection

from predators and rain,

and also capture the sun's rays
to warm up.

But that's not the end
of their impressive biology.

Their delicate antennae serve
as highly sensitive

chemical-detecting noses.

They have those little pits
that are inside of,

are along the length
of the antennae.

And those sensory pits
are basically capable of,

of detecting kind of
chemical compounds,

and basically olfaction,
or, or smelling.

♪♪

The antennae of the male Bombyx
are loaded with a multitude

of microscopic sensing organs,

known as sensilla, that vibrate
at very high frequency.

They can home in on the one
kind of pheromone molecule

they are looking for,
among all the other ones

in suspension in the atmosphere.

In fact, some researchers
believe that the silk moths

have some of the most
highly developed senses of smell

in the living world.

Males are thus able to detect
a female

from over six miles away,

an extraordinary feat
which scientists working on

the detection of explosives
or toxic gases

would love to harness.

♪♪

Valérie Keller and her team
are part of a program

for protecting
civilian populations.

You can see on the antennas
that the sensilla's structure

is kind of like tiny sticks.

We drew inspiration from them.

In fact, we are trying to do
bio-inspiration by making

a synthesis in the lab
that enables us

to duplicate this architecture
you see in nature.

Mechanically duplicating

the anatomical genius of the
Bombyx is not an easy task.

Valérie Keller's team
is creating a forest of sensilla

via a chemical reaction
on a titanium base.

The result is a forest-like
arrangement

of titanium dioxide nanotubes.

If a chemical molecule
in the air

attaches to the nanotubes,

its weight changes the vibration
frequency of the forest,

slowing them down in a way
that can set off an alarm.

TNT, sarin gas,
and other toxic chemicals

all have their own weights.

Nanotubes are programmed
to react to those signals

to trigger alarms.

At the French-German Research
Institute of Saint-Louis,

Denis Spitzer foresees a
big future for these detectors.

We can come up with stationary
detectors, but then we can go on

basing them on the butterfly,
that is,

we can start to make
the detectors fly,

and the idea came to us
to implant these detectors

on drones, so that the military

or civil security people
can detect dangerous compounds.

It could be war toxins,

or sarin gas, or other extremely
dangerous compounds.

Because when the person feels

the first symptoms of gas like
that, it is already too late.

Drone surveillance
of large urban areas

could save major populations
from terrorist gas attacks.

♪♪

The amazing evolutionary tricks
of butterflies and moths

are not limited to their wings,
or their antennae.

Unlike many insects,
they don't have what might be

recognized as a mouth.

Most of the butterflies
and moths that we, we think of

have a sucking mouth part,
like a proboscis,

that is kind of coiled up,
that kind of is like a straw.

And it kind of extends outwards

with this cranial sucking pump,
and it sucks up

nectar from flowers.

♪♪

Many butterflies live
only for a few weeks.

But one, called Heliconius,
stands out,

with a lifespan closer to
six months.

♪♪

This relatively long-lived
butterfly fascinates

Adriana Briscoe
and Larry Gilbert.

One of the ways we think
they can live so long

is because they have changed
their diet.

They live a long time because
they have developed this ability

to harvest pollen.

♪♪

While most butterflies
feed mainly on nectar,

Heliconius adds pollen
to its diet.

The pollen sticks to the entire
length of its proboscis.

The pollen might keep
the butterfly healthy,

but Adriana has found
a possible medical application

derived from the way
Heliconius digests the nutrient.

She's collaborating with
chemist Rachel Martin.

This is the part of the
proboscis

where fluids can go in...
Mm-hmm.

And they can also go out.

I was really fascinated
to find out that

it acts like a sponge.

I was kind of always
picturing this being

like a giant drinking straw.
Oh, yeah, no.

You can see that there
are these ridges

shown in green,

and those are perfect grooves
for pollen to get stuck in.

When the butterflies

probe the flower,

and the pollen grains start to
get stuck in those grooves,

the butterflies then release
saliva from the tip

of their proboscis,

and that starts to glue things
together.

It makes sense that
the butterfly would have enzymes

that are really optimized

for getting into those little
nooks and crannies,

and digesting the protein,

because pollen is about
20% protein, so it's a...

That's a lot.
It is a lot.

The Heliconius's long life
might be explained in part

by this intake
of high-protein pollen,

which it actually digests
on the outside of its proboscis

thanks to a very particular
type of enzyme.

That enzyme is known
as cocoonase,

because it was originally
discovered in silk moths.

Silk moths have one version
of this enzyme which they use

to digest their silk cocoons

so they can escape.

If that enzyme
is not functioning,

they die in their cocoons.

By extracting this cocoonase
enzyme to reproduce

its dissolving properties
on a large scale,

Adriana hopes to alleviate

potentially serious medical
conditions like blood clots.

Blood clots are very common
in the United States.

It turns out you can take
cocoonase, and in a test tube,

you can mix it up
with a blood clot

and it'll break it down
into its component parts.

♪♪

Like the silk protein fibroin,

the cocoonase protein is also
compatible with human biology.

And the longevity Heliconius

may glean from pollen shows
how tightly the evolution

of butterflies depends on
the plants they feed on.

Plants and butterflies have
mutual evolution.

From egg to chrysalis,

many butterfly species are born,
grow up, and metamorphose

on individual plant species
with which they are associated.

You sometimes have a species
of butterfly or moth

that is the only thing
that can pollinate

a particular, a particular
species of, of flower.

And so, these really tight
interactions mean that

if we lose one of those members
of this partnership,

then you often end up losing
both species.

♪♪

The fates of butterflies
and plants are forever linked,

to such a degree that we cannot
hope to preserve

butterflies without preserving
their ecosystems.

Today's climate change may have
very unfortunate consequences.

♪♪

Spring has come to Mexico,

signaling to the monarchs
the time to return.

But these butterflies,
who migrated south in the fall,

now have to fly back north.

♪♪

How will they know which way
to fly?

Christine Merlin keeps a small
group of monarchs for study.

Just want a cooperative one.

You know, cooperate with me.

That one is actually in the
process of laying an egg.

She wants to explore and
understand which specific genes

trigger the migration
and guide them on their way.

This one just did.

Okay, this one is getting ready.

Christine believes that changes
in the environment

trigger a response

in the migratory genes
of the monarchs,

a process known as epigenetics.

I'm not as good as my student.

So with each butterfly's egg,
she analyzes a range of genes

to discover which are involved
with the timing

of the monarchs' navigation
and which

with the direction they follow.

One of the best example
of epigenetic changes

that occur in, in
monarch migration

is that of the recalibration
of their sun-compass orientation

from southward in the fall
to northwards in, in the spring.

And...

We do believe that
epigenetic changes

are responsible for this switch
in flight orientation.

Migrating monarchs also use

magnetic fields to guide
their flight orientation.

To find genes that allow
monarchs to sense

the magnetic field,
Christine uses a Faraday cage

that blocks the outside
electromagnetic influences.

There, she generates her own
magnetic field

to test the reaction
of the monarchs' behavior.

We use a magnetic coil

to test the response
of monarch butterfly

to the reversal
of the inclination.

And when butterfly sense
and respond to this reversal,

they start flapping their wings
really strongly,

they have an active flight.

And once we reverse the
magnetic field back to normal,

then the behavioral responses
extinguishes itself.

♪♪

The evidence is in: monarchs
are genetically programmed

to align with the magnetic
field, and we can see them

flap their wings
when they sense it.

When the seasons change,
causing a change of temperature,

a change of the angle
of the sun,

as well as a change

in the daily sunshine duration,

the butterflies' genes

trigger a signal to migrate.

♪♪

When in Canada and the U.S.,

the onset of fall signals
departure.

♪♪

"Colder... go south!"

When in Mexico,
spring tells them, "Go north!"

Given the extent that monarchs
depend on temperature,

it's not surprising that
climate change

worries researchers like
Delbert,

who monitors monarch populations

in part to understand the risks
we all face.

In that way,

by studying monarchs' biology
very closely,

it indirectly tells us

our own impacts on their
environment that they cover.

So we want to watch what's
happening to them,

watch how they're being
impacted, such that we know then

how other species may
potentially being impacted,

because they're being impacted
by those same climate change.

♪♪

Well, butterflies and moths
are really a big part

of the whole ecosystem.

So, if we were to lose
a certain species,

or groups of species, like
butterflies and moths,

we'd lose pollinators, for sure,

but we'd also lose
an important diet for birds.

We'd lose an important diet

for other insects, like
dragonflies.

We'd lose important diet items
even for people.

Because there are people that
like to eat these, these

as food items.

So, it's a kind of
a cascading effect.

It's not just that you would
lose this one insect.

You would actually lose many
members of the community

to which it belongs.

And that's, I think, the thing

that we're, we're working
against.

♪♪

Butterflies and moths

are inspiring scientists
and engineers

to create remarkable inventions.

From the nanoscopic structures
on their wings

that create color
and transparency

to their ability to repel water
and fight infection,

they offer lessons
about what's possible

at the very smallest scale.

But they also present us
with a warning

about what's at stake if we fail

as stewards of this endlessly
inventive natural environment.

♪♪