Bugs That Rule the World

Ummat: When we think of predators, we often think of big animals, like lions, hawks, or eagles.

But insect predators are all over the place.

And if you shrink yourself down to size, I think you'll find much more ferocious predators in the insect world.

Sylvana: Insects are some of the world's best predators.

They have all these specific adaptations in order to catch and hunt their prey efficiently.

Narrator: Insects may be small, but it's a bug eat bug world.

And insect predators have honed their skills with deadly precision, tiny predators with extraordinary arsenals, some straight out of science fiction.

Sylvana: Insect predators typically have really big eyes and great vision.

They've had millions of years to adapt of being apex predators within the insect world that their kill rates are so efficient.

Narrator: More than just efficient killers, these tiny beasts of prey may hold secrets to incredible powers and warnings about our changing planet, From the stealth and agility of the praying mantis, master of the art of the ambush to the jewel-toned dragonfly, whose summer acrobatics are the deadly flights of an aerial assassin.

Small, lethal, and essential to the ecosystems where they rule.

Ummat: They are extremely fast when they need to be.

They're extremely agile.

And all these things combine to make them superior predators of the insect world.

Narrator: In the cutthroat world of bugs, survival takes ingenuity and skill.

And one of the forest's top predators is on the hunt.

Ummat: Most insects walk with six of their legs.

A praying mantis has four legs that are used for walking, but its front legs are modified as raptorial appendages, which it uses to strike out and grab prey.

So it's really built for this extreme predatory lifestyle.

Gavin: If they see something move in front of it, they visually track it.

They orient towards it.

Their raptorial forelegs are modified so extremely that there are these spines sticking out of their femur and their tibia, which form basically a mechanism, where they can reach out, grab, and hold even much larger insects than themselves.

Narrator: A praying mantis blends perfectly into her surroundings, and to make her kill, she sits stock-still.

Ummat: They are ambush predators, so they wait for the prey to get close enough, and then they strike out in the blink of an eye and capture their prey.

Narrator: While the victim is still alive, mouthparts, like an array of sharp fingers, dig into the meal.

Gavin: There's a certain brutality in how they consume their prey.

They have very strong, robust mandibles.

So they're chomping through the exoskeleton of another organism.

They eat pretty much everything.

So they go from one end... to the other, dependent on what's closest to its mouth.

Narrator: With their lethal spikes and mysterious eyes, praying mantises also catch our attention in a way that other insects often don't.

Gavin: They're an insect that looks back at you when you look at it.

You think that they're looking at you in a way that they understand that you are another organism.

They're charismatic.

They look cool, and you think something different about them.

It captures the imagination of how an organism like this exists within the environment and how it has adapted within that ecosystem.

[Vehicle running] I have always been interested in insects.

I became an entomologist, I think, before I even went to high school.

Now I'm a praying mantis specialist.

I study their deep evolution.

I study their species diversity.

Narrator: Dr. Gavin Svenson is on a trek to a place with the highest mantis diversity in the world.

Gavin: I began my work back in 2001, trying to ask the question of where they came from and how they became distributed where they are today.

And why do they look and behave like they do today?

Here we are.

Narrator: Throughout the world, there are over 2,400 species of praying mantises.

Most are found in the tropics, and over 1/10 of them, here in Brazil.

In the heart of the Amazon, Gavin is looking for the very roots of their evolution from over 140 million years ago.

Gavin: What makes the Amazon so unique compared to other areas is there's dramatically different lineages of praying mantises that live there.

There are very highly adapted modern forms, but there are, then, these really interesting, unique ancient forms.

And these are the lineages that have been around since the origins of praying mantises themselves.

[Loud clank] Uh, maybe I better go down there, huh?

Yeah, can you catch it at that level?

Yeah.

OK. Now I need that splitter.

We're at an emergent canopy tower north of Manaus in the Amazon.

We're in a pretty ideal location, where the tower goes well above the canopy height.

So what we're going to do tonight is set up a mercury vapor lamp, or metal-halide lamp.

It's basically a lamp that's tuned specifically to attract insects.

It throws off a lot of ultraviolet light, and it's really, really bright.

Narrator: The 138-foot tower provides a rare opportunity to mount lights at different levels from the forest floor to the canopy, drawing in a virtual layer cake of mantis diversity.

Gavin: For praying mantises, I'm trying to find the rarest things.

You have enough to plug in?

Awesome.

[Generator rumbling] Running lights is the most efficient and effective way of doing it.

I mean, this is here, this is the 50/50 shot.

Man: Right.

Are the bugs better over there?

Or are they better over there?

Like...

This is the difference between a successful night... [Laughing] Right, right.

and a not so successful night.

Gavin, voice-over: Harold's been working here on a project to really document the overall diversity of the nocturnal insects that are flying at night.

Might actually, so we don't trip, so we can around it, you want to tie it on up there, above...?

Oh, yes, good idea, good call.

I'll tie it here.

Gavin, voice-over: There's no lights out here.

And there's no lights this bright at this elevation.

So this is a totally unique signal for insects to be able to see.

I mean, if you look west, it's the same forest all the way to the border of Ecuador.

It goes for hundreds of miles.

Harold: It's just so exciting.

Like, every night as it starts to get dark, you just feel the anticipation building.

Like, what is it going to be like tonight?

You know?

Gavin: This is one of the most interesting times of day, this crepuscular time of day.

Primates are going to bed.

And then the insects are all starting to wake up.

So it's like a shift change in the rainforest.

If there is a place in the world that you're going to find some of the coolest stuff, it's going to be sitting on this tower tonight, running a light.

We're waiting for the star of the show.

This is the opening act.

Narrator: As soon as the sun falls, the first bugs begin to arrive.

Gavin: You never know what you're going to find.

It's always a surprise when you walk up to it.

You just have to hope that you're in the right place at the right time.

Where are you?

My God.

There he is.

This is a Mantoida.

It's the second earliest branch in praying mantises, so it's really, really ancient.

Goes back a long, long ways.

So you can find fossils of these things that look pretty much the same as these.

There's just layer upon layer upon layer of different groups of insects that are living, forest floor all the way up to the canopy.

That's a new one.

This one was hanging out down at the bottom of the sheet, feeding, eating all the other insects that are here.

If you're a predator and you eat insects, this is kind of a great place to hang out.

Narrator: Gavin collects the tiny predators to be photographed and documented to get a baseline of the region's mantis diversity.

As insects disappear in other parts of the world, there's little known about how praying mantises are faring in the deep forest.

Gavin: I think it's extremely important to understand the biodiversity and the environments around us all the way down in one of the biodiversity hotspots on planet Earth in the Amazon.

If we don't understand what's there, we don't know how it's changing.

We don't know if there's a problem.

Narrator: Other predators are also drawn to the lights.

Harold: Look at those jaws.

Yeah.

This is another longhorn beetle.

Those jaws are brutal.

Yup.

I think this is a genus Photina.

This mantis is called Angela.

That's the genus.

And it's a unique lineage of mantises that mimic sticks-- Angelinae, a really unique kind of mantis.

Narrator: The lights have brought in a mantis that would be difficult to spot in the daytime.

Gavin: They act as much like a branch as they possibly can or a little twig.

Blending in is the name of the game.

If it sees a bird or something come along that it thinks it's in danger for, it'll even act closer like a branch by sticking its legs out in front of its body to break up the profile, so a bird can't quite determine if that is an insect or a twig.

It's literally pretending that it's something else.

Narrator: In addition to their hunting skills, praying mantises are also masters of disguise.

Gavin: Camouflage is one of the core strategies of survival for praying mantises.

If they don't do it well and they don't really own it, they are detected fairly easily by birds or other predators.

Narrator: Beyond sticks, mantises have evolved bodies that look like bark and even dry dead leaves.

Ummat: The dead leaf mantis not only has evolved to look almost identical to a dead leaf, but it also behaves like a leaf swaying in the wind.

Gavin: When you see highly specialized species, like dead leaf-mimicking praying mantises, the next question you ask is, How can something like that come to be?

So millions and millions of years ago, this thing's ancestor might have had a fraction of a fraction of an advantage over the other individuals within that same population.

But if you compound that over millions of years, that fractional advantage can lead to adaptation and selection and refinement of a convincing camouflage form to the point where the outcome can be so unbelievably convincing that you don't think it's possible.

Narrator: This long evolution has led to perhaps the mantis masterpiece, the ingenious disguise of the orchid mantis.

Gavin: What makes them one of the most amazing species on earth is that the female masquerades as a flower.

They're derived from these flower-associated ancestors, but they themselves no longer sit on a flower to catch pollinating insects.

They have become the flower to attract pollinators just to their body.

Narrator: Bees and flies are lured by the predator's shape and vivid color... but the costume has a dual purpose.

Gavin: It's masquerading as a flower to both attract its own prey, but it's masquerading as a flower to hide from its own predators.

Sylvana: Sometimes it's hard to wrap your head around how closely insects resemble the environment that they live in and that local adaptation has put pressures on these insects to look like inanimate objects or to look like other insects that are also in their environment.

I mean, you won't see something on that level in a lot of other organisms.

Insects do it the best.

Narrator: The tower has drawn in a variety of mantises, but some species don't come to lights, which means Gavin has to go find them.

He's on the hunt for hard-to-spot bark mantises, small, fast-moving species that hide on trees, hunting for flies and beetles.

These small but speedy mantises are some of the oldest in the mantis family tree.

Gavin: They're no larger than two inches.

Some of them are much smaller than that, and they basically stick to living right on the tree trunks.

They're the deepest, most ancient living lineage today... so it really provides you the opportunity to see what is an ancient, ancient praying mantis lineage behaving today.

It's a glimpse into the past.

Narrator: One species of bark mantis is high on Gavin's agenda, one he has scientifically described but never found in the wild.

Gavin: One of them from here I named for my daughter, Liturgusa tessae, and my daughter's name is Tessa.

So there's a chance that I can actually find a mantid that I named after my daughter, that I've never seen alive.

So that would be cool.

I'd score some dad points with my kid.

The most challenging part of it is not actually the finding of it.

It's the catching of it.

These bark mantises will essentially, like, they'll see you coming and they'll run to the other side of the tree trunk, kind of like a squirrel does.

So what I do is I walk through the rainforest and I find these smooth bark trees... and I take my net and I sweep it under the backside of the tree and work it up and down.

And that usually startles some to the side of the tree that I can actually see them.

And then from there, it's like the game of chasing a little critter that runs extremely fast up and down a tree.

Narrator: Buried in the bark, Gavin finds a sign that he's on the right track.

Gavin: So this right here, that's a Liturgusa egg case.

That's the egg case of these bark mantises.

Narrator: An egg case means there could be mating adults nearby.

For praying mantises, even reproduction can be a chance to feed.

Mantises can mate for up to 2 hours.

And if the female gets hungry, she may help herself to a snack... sometimes even her partner's head.

But even decapitation doesn't end the affair.

The headless male can still mate for several hours.

The female will lay up to 180 eggs encased in a foamy mass called an ootheca.

It hardens and protects the eggs against the elements until a small army of tiny mantises emerge-- instant predators, ready to eat anything, including each other.

That's a bark mantis right here.

This is a mid-sized species.

It looks to be the right proportions.

It looks like it has the right colorations.

Kind of roughly matches the description of the species that I named for my daughter.

Narrator: Gavin described the species using a specimen from a museum in 2014.

Now his chance to see it in real life could easily slip through his fingers.

Gavin: This thing has a lot of escape paths.

And I'm also nervous because I really, really want to catch this one.

OK, friend.

I got it.

That was easier than I thought it was going to be.

It's the right proportions.

Yeah, there's a little bit of coloration in the base portion of the hind wing, and then the rest of it would be more black in color, but the best way to figure this out is getting it into something I can see it more clearly.

And my hands are shaking as well because I'm excited.

Yeah, yeah.

When you see something you really, really want to catch and it's hard to catch.

Here it is.

Safe and secure.

Narrator: Over the course of four days and nights and a lot of stairs, Gavin starts to build a solid sample of the forest's mantis diversity.

Gavin: How could you not be happy with this, this sitting in your hand?

After this amount of time, you know, I still feel like a kid looking at one of the most fascinating groups of organisms on planet Earth.

Narrator: After careful research, he discovers the bark mantis he caught was not, in fact, the prize he had hoped.

Gavin: So it's a different species distributed in the same region of the Amazon.

As a scientist, I never want to make a confirmation until I'm certain and I have verified it.

So this is one of those scenarios where it's like, I would have gotten awesome dad points if I found the mantis that was named after my daughter.

But, hey, the truth hurts.

You can't win them all.

Narrator: In total, the lights only drew in 30 individual mantises.

But of those, 17 were different species.

Gavin believes this high diversity in such a low number suggests there's still much more to discover here.

And his findings are one step closer to understanding how praying mantises are doing in the Amazon.

[Generator rumbling] Gavin: One of the challenges that entomologists have is that if we are truly to document insect diversity decline in an area like this, you look at a sheet like this and a lot of what's on here may not be known to science yet.

So how do you demonstrate that we're losing things or maybe we're not losing things when you don't even know the baseline information?

We're a species that sent someone to outer space, and the fact that we don't know all of the diversity that's within an ecosystem like this.

There's a lot to learn.

This is an-old timey projected Amazonian picture show.

Narrator: In all their specialized forms, mantises have evolved the perfect suite of weapons to emerge as apex predators, and as we're now learning, they've also developed the brains to use them.

[Beeps] Man: I've studied bumblebees.

I've studied praying mantises.

And I've also done some research on human psychology.

I think my fascination started from the fact that there were all these huge numbers of very different creatures, who had very different ways of viewing the world.

How do different kinds of brains or minds solve the problems that they face?

The real interesting thing is whether they come up with different solutions, or the same solutions to the same problems.

Narrator: Dr. Vivek Nityananda is trying to peer inside the mind of insects.

He wants to understand what makes a bug with a small brain such an efficient predator.

Vivek: My lab focuses on insect cognition.

So essentially we're asking, How do insect minds work?

How do insect eyes work?

And how do they both come together, whether that's different or similar to humans?

Narrator: A human brain is made up of over 100 billion neurons.

A mantis brain functions with around 1 million.

But a surprising number of them seem to be specialized for one thing--hunting.

To get a mantis' perspective and learn what makes them such lethal hunters, Vivek's lab devised an unconventional experiment, a 3-D insect cinema.

Vivek: We wanted to show the mantises something on a computer screen.

The best way we hit on to do that after a lot of kind of failed attempts was to design 3-D glasses.

Narrator: He uses beeswax to temporarily apply the glasses, which filter the color spectrum to blue and green, the colors mantises see best.

With the mantis at a fixed distance from the screen, Vivek plays images that simulate a moving target.

Vivek: So if you see the mantis try and reach out and catch the prey, we know we've succeeded in fooling the mantis.

Yeah, that's excellent.

So we got two strikes in a row there.

And sometimes when they're really motivated, you can get up to 6 or 7 in one go!

They might just really go wild.

Narrator: The team is finding that it's not the shape or color of the prey that triggers the mantis, simply motion at the right distance to grab.

The stimuli we use are just, like, black circles, but they really trigger this impulse for the mantis to try and catch something.

Narrator: If the target appears too far, the mantis saves its energy.

If it's within striking range, it triggers the attack impulse.

This motion-focused vision allows mantises to ignore color and patterns and see through camouflage by focusing solely on the movement that alerts them to prey.

Vivek: What we learned about Mantis vision is that it's really helpful in terms of them spotting prey, in terms of judging depth, also helping them spot things that are camouflaged against a background as they move.

They're really quite specialized in detecting prey.

I think at one level, the fact that they use these smart, simple solutions doesn't mean that they're, well, less intelligent, or more intelligent.

I would just say that that's a different approach, a different way of dealing with the same problem.

That comes from the fact that that's what its ecology, its lifestyle really demands.

So it's really evolved to be very specialized, to be good at what its life involves.

Narrator: Vision, agility, and their specialized bodies have made mantises the top hunters of their tiny kingdoms.

But there's another insect predator even more ancient and more lethal.

It has similar weapons but deploys them in the air.

Sylvana: If you thought praying mantises were the apex predators, wait 'til you see dragonflies.

Because some of the same mechanisms that praying mantises use, like great vision, big eyes, dragonflies also have that, but they take to the air when they're catching their prey.

Narrator: Dragonflies, and their cousins damselflies, are from the order Odonata, which means "toothed ones," and they use their teeth to capture mosquitoes and flies with astonishing accuracy.

Jessica: Dragonflies have a pretty high success rate.

Mantises, just like dragonflies, can miss.

But I think dragonflies miss less often.

Narrator: With nearly 360-degree vision, dragonflies can see above, below, and all around, and have the aerobatic ability to pivot and catch their prey in flight.

Ummat: The dragonfly can catch about 95% of the prey that it goes to attack.

That is an extremely high attack rate for an aerial predator.

A peregrine falcon is only able to capture about 20% of the prey that it goes after.

So these animals are extremely efficient.

Jessica: They're able to do some kind of complex interception-style hunting, so they don't fly to where a fly or prey item is now.

They, like, figure out some math and then go to where the fly is going to be, and they cut it off at the pass just like a lion would do.

Narrator: A single dragonfly can devour up to 40 mosquitoes a day, making them essential for regulating aquatic ecosystems.

Around the world, there are more than 7,000 species of dragonflies, the most successful predators in the animal kingdom.

But like most insects, they're facing threats from all sides.

And one in six dragonfly species is at risk of extinction.

Some could disappear before they're even discovered.

Deep in Guyana's rainforest, on South America's northern edge, Dr. Jessica Ware is searching for aerial predators.

Jessica: When we think about diversity, there's about the same number of species of dragonflies and damselflies as there are all of mammals.

Narrator: A few years ago, over 40 new species of dragonfly were identified here.

And Jessica knows it's just a hint of what's out there.

Jessica: This is a good area to get giant helicopter damselflies.

They'll usually perch just above our eyeline.

Narrator: She's hoping to find species to help fill in the dragonfly tree of life, a chart of dragonfly evolution throughout history.

Jessica: People have been trying to figure out how dragonflies are related to each other for hundreds of years.

You can make a tree, or a phylogeny, with appearance data, which could be from external or internal characters.

You can also use genetic information, which is what we often turn to now.

When we go to Guyana, we're looking to sample biodiversity, but then also the taxa that we find we sequence.

This also goes to part of this tree of life of dragonflies, and we often find new species.

Libellulidae.

Just caught Uracis.

Uracis are Libellulidae.

This is a male.

You always can kind of tell.

This one has black tips on the tips of its wings, which are very noticeable.

That's a good catch, Susan.

Thank you.

Narrator: The specimens they collect will help piece together how these highly efficient survivors evolved and dispersed around the planet.

Jessica: We're describing species of insects at a pretty fast rate.

And for dragonflies, there's several handfuls of dragonflies that are described every year.

We think that we're not close to finding all of the dragonflies that are out there.

So I got one of the Libellulidaes, the skimmers.

You can tell this is a little bit of an older guy because its wings have tears on them.

Narrator: The dragonfly's success began before the time of the dinosaurs, when it first developed its signature wings.

Gavin: Dragonflies are masters of aviation.

They're incredible fliers.

They are one of the earliest evolving terrestrial insects.

Jessica: We know from the fossil record that the first flight probably was around 400 million years ago, and it probably looked something like a dragonfly.

Narrator: A dragonfly's 4 wings can maneuver independently.

With the most developed wing muscles in the insect world, they can speed through the air at up to 25 miles per hour.

Their iridescent colors help with regulating body temperature and communication with potential mates.

It's unlikely any color signaling goes undetected.

Nearly 80% of their brains are dedicated to vision.

Jessica: Their head is basically just two giant eyes.

And then the eyes can rotate like this.

And that way, they can see a really wide range.

They're able to see predators, they're able to see prey.

Narrator: While a dragonfly's eyes are nearly connected, The damselfly's are widely separated, possibly giving greater awareness of prey to the side and rear.

But dragonflies don't just use their enormous eyes to find prey.

They're also looking for love.

And mating is not a simple affair.

For starters, males have two penises.

Jessica: The male and female reproductive parts come together, and then the secondary penis actually is used to scrape out the previous male's sperm or displace it.

When you see males and females come together, it looks kind of heart shaped.

It's like, we call it the copulatory wheel.

And they're together for some time.

Narrator: This delicate dance can last for several hours.

Finally, the female lays her eggs in or near the water, which her larvae need to survive.

Over her short lifetime of a few weeks, she can lay thousands of eggs, an essential food source for fish, frogs, and other aquatic creatures.

After a week-long gestation, the hatchlings, called nymphs, emerge looking nothing like their parents and begin their training as voracious predators underwater.

Jessica: Most dragonfly nymphs, as we call them, are larvae.

They burrow in the sand or the rocks that are at the bottom of the water.

Their mouthparts consist of, like, a hinged structure, and it shoots out like that.

They have these little claws here.

They grab the prey item and then bring it back to their mouth.

Sylvana: And in order to power that jaw, they actually take in water through their rear end and constrict the water, and that pressure then shoots their jaw out.

It's almost alien-like how it extends.

It looks like a super modified elbow that's able to shoot out from underneath their jaw and grab a prey and bring it back in so quickly that the prey has no idea what just happened.

Narrator: A dragonfly nymph will spend up to five years as an underwater hunter.

It'll molt as many as 12 times before preparing for its final transformation.

Sylvana: Once they're ready to emerge as an adult, it'll crawl its way out from the water.

They'll get to a stalk or somewhere high up.

It then rips its cuticle open and is able to shed that last bit of its exoskeleton and emerge as this new adult.

Narrator: Within minutes, it takes its ravenous appetite and lethal hunting skills from the water to the sky.

Ummat: It's incredible because these insects have to breathe underwater, see underwater, and deal with all these underwater challenges.

And as adults, they'll have to see in air, fly in the air.

It's an incredible transition.

Imagine a bird that completed its development as a fish unwater.

It's incredible.

Narrator: Dragonfly wings have been so honed to perfection, they've carried them around the planet.

And far from Guyana, they've learned to thrive in some surprising habitats.

Jessica: Our vision of where insects live, we tend to associate dragonflies, in particular, with being kind of in hot, maybe tropical, environments.

But actually, there's over 40 species of dragonflies that live north of the Arctic Circle.

Narrator: Dragonflies are well-equipped for survival, even in extreme cold.

But for a creature whose life begins in the water, freezing temperatures require a mind-boggling ability.

Dragonflies are some of the most resilient insects in the world.

And survival in the far north means dragonfly nymphs must withstand being frozen for more than half the year before thawing out during the summer months.

This superpower could unlock a mystery with powerful ramifications for human longevity.

Jessica: So this idea that perhaps Arctic taxa hold some clues to cryopreservation is one that we've been trying to unravel.

In any of these Arctic habitats, I think getting aquatic species in general will be really key, so we can understand how they're able to survive under ice, and frozen, for sometimes multiple winters.

Somehow they do it.

Narrator: North of the Arctic Circle, Jessica and her team have only a tight window of time to do their work before the weather closes in.

Jessica: We have to break open the ice, and that way, we can use these nets called dip nets.

Kind of have to rub and nudge the emergent vegetation, which is now underneath the ice.

That's often where we find some of the nymphs are clinging.

And hopefully, we'll find a lot of dragonflies.

See, normally, you would just do this, and it would just be... [Imitates humming noise] You know, so much movement in the net.

And here, almost nothing, so you have to really look.

Otherwise you'll miss them.

Pretty icy.

Hey, an Aeshnidae exuvia!

The shed skin, the molt.

Pretty big size, too.

So that is a good sign.

So I think I'm going to try going deeper.

Narrator: The team continues the search, but the temperature quickly drops.

Ooh!

[Laughs] You OK?

Yeah, I'm fine.

Jessica: Working in the Arctic is challenging no matter what season you're in, but the fall and winter seasons, it actually can be quite dangerous.

This is what my grandmother told me to never do-- to stand near broken ice.

[Laughs] And your feet are kind of cold.

We're working with freshwater.

And so what that means is that all of our bodies, our snow pants, our mittens, our gloves, everything gets wet and immediately freezes.

OK, my foot just went all the way.

Scientist: My gloves are also, like, frozen.

Narrator: Collected nymphs are placed in a preservative to protect them so Jessica can determine what genes are activated that allow the nymphs to survive being frozen.

Jessica: We expect some genes will always be expressed because they're just housekeeping genes that the organism, the dragonfly, needs to survive.

But there might be ones that are expressed only in the winter, and those are the ones that we want to look at.

Maybe we see a pattern.

Maybe it will be a clue to this cryopreservation.

He's right there... Is this it?

You're so close... Oh, I see it.

Right there!

Yeah, OK. Ohh.

Narrator: Of the 40 species of Arctic dragonfly, Jessica has so far found one, but it may have to be enough.

Weather is not on their side.

OK. Whew.

It feels like it's, oh, you know, -3, -4.

I definitely feel like my eyelashes are freezing.

Here, you have to really work against the clock.

Oh, wow.

Look.

Scientist: So we just found this damselfly, and right now, it's not moving at all and it's frozen solid.

But most likely, if we let it thaw, we think it'll start moving.

Is it moving?

Yup.

[Chuckles] I'm so excited.

[Laughs] Narrator: Only a few frogs and other reptiles are known to freeze without destroying their cells.

The secret to this incredible capability has long evaded science.

It may lie within the samples of these Arctic dragonflies Jessica has collected.

Jessica: Look at all these Swedish samples.

"Sweden," "Sweden," "Sweden," "Sweden."

"Sweden," "Sweden," "Sweden."

So we have a lot of samples from the different expeditions we've done.

And for the Arctic work, we've been sampling in Alaska, but we've also been sampling in Sweden, Finland, and Norway.

A lot of the Arctic stuff is in here, and it's going to stay in here.

We have to keep it very cold because, of course, we collected it frozen and we want it to stay frozen in this special solution that we have it in.

So today is extraction day.

And so we're going to be taking a leg off of these dragonflies.

We're going to put it into a tube with some chemicals that basically make the cells explode, and then the DNA will float into a solution.

And that's the DNA that we want to capture.

Hopefully, these little nymphs will tell us something about the genes that we think might be allowing them to preserve themselves in this frozen climate.

Once we have an idea about what those genes are, then we can start trying to do some experiments with those genes.

Knowing what allows something to stay frozen would be a great mystery.

Like, that would be great to solve.

We're not very good at that as humans.

But if insects are able to crack this and be able to stay frozen and thaw with ease, there's some biomedical advantages to knowing what that clue is, which is very cool.

Narrator: Dragonflies and damselflies have adapted to survive on every continent but Antarctica.

But their wetland habitats are disappearing three times faster than our forests.

And even these fierce predators are vulnerable.

[Clicks, beeps] Their ability to reproduce depends on clean, fresh water, which makes these elegant predators tiny sentinels over a changing environment.

[Beeps, clicks] [Indistinct conversations] Narrator: Far from the bustle of Lagos, Cross River State forms the largest natural park in Nigeria.

Its 2,500 square miles make up the oldest rainforest on the African continent.

Each mountain and humid valley forms their own mini climate, a perfect habitat for wildlife on a miniature scale.

Narrator: Researcher Ojonugwa Ekpah is searching for dragonflies with a sensitive side, so sensitive, they require extremely pure environments to survive.

To reach such unspoiled habitat, he has to trek to a river hidden deep inside the forest.

Narrator: Ojonugwa's mission is to photograph and report the rare species along this river and to determine what they tell him about the state of their habitat.

[Leaves rustle] Narrator: Because of their dependence on a clean environment, dragonflies and damselflies can be seen as bioindicator species.

If they're present, the environment is in good shape.

If they're not, it's a warning.

Narrator: With the African continent set to undergo seismic growth over the next century, scientists like Ojonugwa fear that if insects are trying to tell us something, few are listening.

Gavin: A lot of aquatic insects, they depend on water quality.

Colder water and higher quality water diffuse oxygen better and provides better resources for things to exist in that water.

Narrator: Aquatic insects depend on a healthy environment to survive, but the ecosystem also depends on them to function.

These little predators and their bizarre life cycles form a critical link between all animals in the habitat.

Jessica: There are freshwater insects that are actually doing decomposition of detritus and filtering.

So when we think about the services that insects do, they're actually kind of shaping all of the terrestrial environments in which we reside, but then they also shape the freshwater environments, too.

Gavin: If they're not there, other things can't survive, so native fish, turtles, frogs, you name it, all these things that rely on these insects.

Narrator: From catching spiders in the forest to intercepting flies and mosquitoes over wetlands, perfectly honed insect predators shape their environments with every bite.

But when it comes to maintaining the planet, few animals compare to the most industrious and abundant insects of all--beetles.

"Bugs That Rule the World" is available with PBS Passport and on Amazon Prime Video