Butterfly Blueprints

♪ ♪ NARRATOR: 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.

NARRATOR: Brilliant color without paint.

(translated): What we see here is a close-up.

We see that the blue comes from the background scales.

NARRATOR: 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.

NARRATOR: Even an unsinkable metal.

CHUNLEI GUO: 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.

NARRATOR: 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.

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

♪ ♪ ♪ ♪ NARRATOR: 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.

NARRATOR: 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.

NARRATOR: 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.

NARRATOR: 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.

(wildlife chittering) ♪ ♪ 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 II, a researcher at the University of Michigan, Ann Arbor, studies the complex life cycle of the monarch butterfly.

GREEN: 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.

♪ ♪ NARRATOR: 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.

GREEN: 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.

NARRATOR: Delbert believes the decline can be used to gauge the level of environmental change that the butterflies encounter on their journey.

GREEN: 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.

NARRATOR: 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.

GREEN: 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.

♪ ♪ NARRATOR: During their diapause, monarchs endure a very sensitive and crucial time.

GREEN: 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.

NARRATOR: 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.

♪ ♪ NARRATOR: 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.

(whirring) 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.

(beeping) Researchers at the Tufts Silklab in Boston have isolated one of the proteins, called fibroin, and have created an innovative material.

FIORENZO OMENETTO: 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.

NARRATOR: 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.

OMENETTO: Oh, so this is the... D'AMONE: (inaudible) net.

OMENETTO: ...(inaudible) net, so these are very nice.

Yeah, but as soon as I stretch them, they are, are breaking down.

OMENETTO: 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.

OMENETTO: 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.

NARRATOR: 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.

OMENETTO: 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.

NARRATOR: 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.

NARRATOR: 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.

♪ ♪ NARRATOR: This fabric is of particular interest for making protective gear for workers operating where they might be exposed to dangerous substances.

OMENETTO: 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.

(wildlife chittering) NARRATOR: 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... (rustling) ...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.

(translated): 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.

(wildlife chittering) NARRATOR: 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.

BERTHIER (translated): 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.

(wildlife chittering) NARRATOR: As it flits through the forest blinking blue, it follows an unpredictable zig-zag path, making it hard to track.

BERTHIER (translated): 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.

NARRATOR: 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.

(translated): 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.

NARRATOR: 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.

NARRATOR: 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.

NARRATOR: 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.

NARRATOR: 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.

(laser humming) At the Institute of Optics at the University of Rochester in the United States, Chunlei Guo has succeeded in creating such structures.

(speaking indistinctly) 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.

NARRATOR: 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.

GUO: 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.

NARRATOR: 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.

WARE: 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.

(buzzing) NARRATOR: 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.

NARRATOR: 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.

WARE: 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.

NARRATOR: 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.

HENDRIK HÖLSCHER (translated): 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.

♪ ♪ NARRATOR: 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.

(translated): 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.

NARRATOR: 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.

(machine whirring) (stops) 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.

(thunder rumbling) BERTHIER (translated): 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.

(water falling softly) And then the beads roll off, cleaning the wing of all of the dust and dirt it picks up along the way.

NARRATOR: 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.

NARRATOR: 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.

♪ ♪ NARRATOR: 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.

♪ ♪ NARRATOR: 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.

NARRATOR: For Radwanul, an implant in the eye cannot be water-repellent like the butterfly wing.

He needs to engineer something different.

SIDDIQUE: 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.

♪ ♪ NARRATOR: 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.

SIDDIQUE: 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.

♪ ♪ (birds twittering) NARRATOR: 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.

BERTHIER (translated): 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.

NARRATOR: 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.

(translated): 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.

NARRATOR: 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.

(translated): The butterfly just has to open and close its wings to regulate its temperature.

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

♪ ♪ NARRATOR: 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.

♪ ♪ NARRATOR: Today, by combining the properties of the glasswing and cabbage white wings, researchers are hoping to develop a new generation of solar panels.

SHANKS: 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.

♪ ♪ NARRATOR: 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.

♪ ♪ NARRATOR: 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.

(translated): 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.

NARRATOR: 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.

(speaking French) (translated): 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 whirring) NARRATOR: Drone surveillance of large urban areas could save major populations from terrorist gas attacks.

(drone whirring) ♪ ♪ (insects chittering) (birds twittering) 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.

♪ ♪ NARRATOR: 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.

♪ ♪ NARRATOR: 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.

BRISCOE: 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.

MARTIN: 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.

NARRATOR: 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.

NARRATOR: 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.

BRISCOE: 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.

♪ ♪ NARRATOR: 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.

♪ ♪ NARRATOR: 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?

(birds twittering) Christine Merlin keeps a small group of monarchs for study.

MERLIN: Just want a cooperative one.

You know, cooperate with me.

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

NARRATOR: 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.

NARRATOR: 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.

(laughs) NARRATOR: 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.

MERLIN: 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.

NARRATOR: 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.

MERLIN: 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.

♪ ♪ NARRATOR: 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.

GREEN: 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.

♪ ♪ NARRATOR: 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.

♪ ♪ ♪ ♪ ALOK PATEL: Discover the science behind the news with the "NOVA Now" podcast.

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♪ ♪ ♪ ♪