[Animals calling] ♪ Ummat: I was not always interested in insects.

When I was a kid growing up in Kenya, I was doing a safari with my father, and we witnessed an elephant fight.

There were two bulls fighting in the distance.

And I could see the flash of tusks, but the thing I remember the most was the sound of those tusks crashing against each other like two giant pieces of marble.

That experience has always stuck with me.

Why do these elephants fight?

Why do they have these huge tusks that they fight with?

Later on, I found out that many of these weapons are replicated in insects.

We have rhinoceros beetles with horns just like rhinos do.

There are tiny flies that have antlers and will fight in miniature, just the way that elk do.

So, the world is actually thousands of times more diverse than I could have ever imagined.

And most of this world is unexplored, and so just by changing my perspective, I was able to realize that the age of discovery is now when it comes to insects.

Narrator: Flying through the air or crawling on the ground, insects influence almost every aspect of life on Earth.

Sylvana: Insects didn't get the same PR team that gorillas and giraffes and lions got, but all the really cool predation and camouflage, all of those cool behaviors that we like to see in bigger animals we can also see in insects.

Gavin: Insects are one of the most dominant organisms to have ever existed on planet Earth.

They evolved hundreds of millions of years ago.

They've survived extinction events, and we don't know that much about them.

Narrator: The more we learn about these tiny marvels of evolution, the more it's clear that insects are in trouble.

Sylvana: Insects have ruled the world for over 400 million years, but we're seeing insects decline in their numbers and abundance all over the world.

Narrator: Not even 400 million years of evolution prepared insects for the threats they face today, and their extinction could have catastrophic consequences for all life on the planet.

Sylvana: They're providing the pollination for the crops that we need to eat and sustain our communities.

They're important to all aspects of our life, and that wide diversity really shows just how amazing and necessary these insects are.

Narrator: The race is on to discover more about the Earth's vital workforce and the delicate balance they sustain... before they're gone for good.

♪ ♪ Gavin: I grew up in Upstate New York.

And I remember, as a kid, we would go to Allegheny State Park.

And the lightning bugs in that part of the country were astoundingly plentiful.

You would drive down one of the roads within this park, and there were so many of them.

It was inconceivable that they would just be flashing at this rate and at this abundance.

Ummat: I love lightning bugs.

They are incredible.

They produce light in their abdomen.

Can you imagine a bird that would glow through its chest?

And different bird species might glow with different colors.

It's like magic!

Akito: They do this with chemicals that they quickly combine in two different chambers in their bodies, and that creates this amazing flash.

So, they continuously do this flashing that allows them to communicate with other individuals of the same species.

Gavin: As kids, you see them when you're camping, you see them in your backyard.

They're a staple of summer.

I don't see that anymore.

I haven't seen that in many, many years, so it tells me that a change is happening and a change has happened.

Narrator: In recent years, the summer sky has lost its spark, as habitat loss and light pollution have shrunk the number of fireflies by up to 70%.

And it isn't just the fireflies that have gone dark.

♪ Narrator: Around the world, people have begun to notice that the planet's most abundant life form isn't so abundant anymore.

Gavin: Insects are the ultimate survivors.

They survived extinction events.

They're highly adaptable.

They can bounce back from environmental disasters.

But there's something happening now that's different than what we know about that's happened in the past.

Narrator: As insects threaten to vanish, scientists warn that we don't even know what we're losing.

There could be as many as 10 million species we haven't yet discovered, and even the bugs in plain sight still hold mysteries.

Narrator: The sheer diversity of insects on the planet means even common species can reveal answers to questions about evolution, mysteries that scientists like Dr. Ummat Somjee are solving one bug at a time.

Ummat: One of the most exciting things about my job is that when I go out for a walk in the forest, I find a little mantis.

Every single time I'll go out, I'll see a species of insect that I've never seen before.

Well, this isn't technically a bug, but it's cool.

It's an incredible experience to always be ready to have that opportunity to be amazed, surprised and have that wonder.

♪ Many years ago, I came across this insect that had these giant brightly-colored flags on its legs.

When I approached it, it lifted up its leg and waved it in this really elegant way.

And when I looked into the literature, I found out nobody had studied it before.

Nobody knew why it did that waving behavior.

And I was amazed.

I was like, here's this extremely beautiful insect, it's relatively common in the area, people know about it, but nobody knows why it has these brightly-colored flags.

So, I started to investigate this here in Panama by trying to rear these insects in a little greenhouse I constructed called the Bug Hut.

We're working with two species of these flag-footed bugs.

This is the matador bug.

It has these brightly-colored yellow and orange and black flags, and this yellow-and-black stripe pattern on its wings.

These insects are plant feeders.

They're specialized on feeding on plant tissue, and they have this long, thin straw-like mouth part that is protected by a sheath.

And when they come across a plant, they'll use their mouth part to pierce into the plant tissue and suck out phloem from the plants.

And also, they'll pierce through the bottom of a flower and feed on nectar.

And so they have these specialized mouth parts to feed on these different parts of the plant tissue.

This bug is gorgeous.

Those bright flags, they really stand out.

When I first saw these traits, I assumed that they might be used in sexual selection or in competition for mating opportunities.

But the more we looked into it, the more we found that this might not be the case.

First of all, we found that both males and females have these brightly-colored traits.

And the second clue was that waving behavior they perform is done by both males and females, and they don't seem to be doing it to each other.

[Chirping] Here we have the second species.

Ah, got it.

This is Diactor.

You see morphologically, they're really similar.

They have the same kind of body shape and these big tibial flags.

Its wings are very dark black, and its flags are very different colors.

When I started studying these bugs, I thought I could catch them with my hands.

I would reach out to grab them, and I would often come up empty-handed.

They were really good at flying away.

♪ I later realized that something I thought would be an impediment to flight, something that made these bugs look like they would--it'd be difficult for them to fly, might actually allow them to fly with greater agility through the air.

And we are finding that these flags act to stabilize flight and might allow these insects to make sharper turns in the air.

So far from being an impediment, these flags might increase agility of these insects during flight.

So we're finding that, like a Swiss Army Knife, this leg has multiple different functions, and we often find that's often how evolution works on these traits.

We are also finding that that waving behavior might be used to distract predators' attack away from their body and towards this appendage, which is detachable.

We often find that they are missing legs in nature, and so they might distract a predator and then fly away.

♪ We're at the stage of discovery now where we can look into the world of insects and ask these questions about extremely conspicuous and beautiful insects, and try to discover more things about how evolution works, how natural selection shapes these diverse systems.

And insects provide one of the most remarkable examples of very different ways that life can be on the planet.

♪ Narrator: All their different shapes and bodies have made insects the most diverse group of animals on Earth, but they're all built around a single successful model.

They have six legs, compound eyes, and the key to many insects' success--wings, which made them the first animals on the planet to take to the sky.

Dino: Insects are amongst the most successful organisms on the planet.

Their sheer numbers, their sheer diversity, their short life cycles, which gives them the chance to more rapidly adapt and evolve.

Insects have filled almost every part of the planet.

Narrator: Insects have seen the rise and fall of dinosaurs and witnessed the dawn of humans.

But recently, scientists began to warn that something was changing, and no one knew the extent of the problem.

Gavin: Often we don't even know what species exist within a habitat, and we are at a serious disadvantage at documenting what we are losing because we don't even know what we have.

Jessica: One of the hardest things about the early people who were raising the red flag, saying something is wrong with insects, was that we didn't have enough data.

But what we needed was a large sample that we didn't have.

And so, enter my colleagues in Denmark.

♪ Narrator: Growing talk of trouble in the insect world prompted researchers at the University of Copenhagen to assess Denmark's bug biodiversity.

The challenge was how to quickly survey an entire country.

In 2017, they enlisted 150 volunteers in an innovative project called Insektmobilen-- "insect cars."

Anders: It all started with an interest in getting more information about biodiversity of insects across Denmark, so at a national scale.

Jonas: We wanted to engage people in monitoring flying insects, wide scale, all over Denmark.

We could just see that this could be a greater way to engage people and have them sample insects over large areas, using their own car with our net mounted on top.

♪ Anders: So we constructed a net, and instruction video they could watch on YouTube.

Everything they needed, basically, were in that package.

Helene: You put this contraption on the car in order to catch insects and to count them, and measure how many there were and what kind.

Narrator: Volunteers drove routes pre-programmed into their phones, and the collected bugs would be compared to a rare data set, an insect survey from decades earlier.

Helene: We've seen anecdotal evidence that biodiversity is coming under pressure.

So, we have fewer insects, fewer bees, and fewer butterflies.

But in order to do something about it, we need to have data, and this is a way of getting data of what is actually happening.

Narrator: The project received an unexpected flood of volunteers, everyday citizens eager to help catch and count insects.

Anders: So, that also meant that we had these two big freezers of samples, and we just almost had too much for us to cope.

Narrator: The project was a success, but the results came as a shock.

The study that had set out to count bugs discovered there were far fewer than anyone expected.

Growing cities and loss of natural habitat had taken a severe toll on the country's insects.

Anders: Because we are relatively many people living in a small country, almost every square meter of Denmark has been utilized somehow by humans.

That puts a lot of pressure on biodiversity.

Jonas: It is mainly because they need places to live.

And we, as a species, we take up a lot of space on this planet, and every time we take up more space, there's less space for other species.

Narrator: The study found that in just two decades, the population of flying insects dropped by 82%.

Another survey in Germany concluded that in just 30 years, 3/4 of the country's insects had disappeared.

Sylvana: Those European studies really put a fire under everyone to understand that this isn't just a certain neighborhood or one country that's finding a loss of insects.

There is a problem, and there's something happening to the planet's insects.

Reporter: Scientists say the familiar buzz of bugs is fading away fast.

Different reporter: Joining us now on the threat of what's been called an insect apocalypse.

Different reporter: Human activity could drive the Earth's entire insect population to extinction within a century.

Different reporter: They might be small, but insects rule the planet.

They make up over 2/3 of the world's 1.5 million known animal species.

They're also responsible for pollinating 3/4 of global crops while forming the backbone of our food chain.

Man: If the insects disappear, we're going to disappear, too.

Narrator: Insects are responsible for one out of every three bites of food we eat.

In nearly every environment, they recycle nutrients into the soil, filter our fresh water, remove waste and decay, and pollinate more than 180,000 plants that stabilize the soil and supply the oxygen we breathe.

Gavin: There's a famous quote, and it goes, "Insects are the little things that run the world."

And it's quite literally true because insects are an integral part in almost everything that happens in the ecosystem.

Narrator: Now ecosystems everywhere are also in danger... as the Earth's tiny workforce threatens to vanish.

Insects are in trouble, and I am worried about insects and the future of not only the life of insects but the life of so much on our planet that depends on them.

Gavin: Human beings are changing their habitat so quickly that insects simply can't adapt and deal with those changes at that rate.

Narrator: Insects are losing habitat to industrial farms, while rampant use of pesticides kills beneficial bugs and contaminates soil, air, and water far beyond their targets.

Growing pollution drastically limits where they can make their homes.

Ummat: It's kind of like death by a thousand cuts.

We're having huge impacts on their diversity and numbers, and we're gonna affect the species distribution on Earth in a way that's equivalent to an extinction-level event.

Narrator: As the planet warms, some resourceful species, like mosquitoes, will simply move or find new territories.

But it's becoming clear around the world that many important insects are unlikely to survive.

Gavin: If we're changing the climate, if we're changing ecosystems just enough that they can't find mates, they can't find food, they can't be successful anymore.

Sylvana: We're losing pollinators, we're losing decomposers, we're losing nutrient cyclers, we're losing food resources, and across the board, all of these amazing ecosystem services that insects provide.

Narrator: Insects do their work in the background, which makes it easy to forget that if we lose them... we lose our food and clean environment, too.

Jessica: If you were to try and measure how worried you should be about insect decline on a scale of 1 to 100, with 100 being, like, you're terrified, I would say you should be 100.

The fate of humanity rests upon insects surviving.

There's no scenario where insects don't survive, where humans survive.

♪ Narrator: It isn't only human lives that depend on bugs.

Insects themselves form a fundamental base of the food chain.

Fish and reptiles in freshwater streams feed on aquatic insects and their larvae.

Birds depend on bugs for protein.

And when we lose insects, the birds follow.

The number of insect-eating birds in the U.S. and Canada has dropped by nearly 40%.

Gavin: A recent study suggests that we've lost billions of birds in the last 50 years.

That's a huge amount of biomass and bird abundance that's now gone.

It's simply gone.

I draw a strong link to insects because of their fundamental role as a food source for birds.

Akito: Even wildlife like orangutans rely on fruit that are pollinated by insects, but they also feed on insects as well.

So, insects are providing orangutans with two ways of survival.

Narrator: With predators all around, insects have devised a mind-blowing array of tactics to avoid being eaten, and they've evolved an unparalleled ability to hide in plain sight.

Gavin: They can look like flowers.

They can look like pebbles on a beach.

They can be bright metallic in coloration.

It's like this inexhaustible supply of new things.

Ummat: Insects are masters of mimicry and camouflage.

We get insects that look like leaves, insects that look like the bark on a tree, insects that look like sticks.

Sylvana: Stick insects are some of the best examples of extreme mimicry.

A lot of stick insects have lost their wings or have reduced the size of their wings because sticks don't fly, and so you have to not only look like a stick but you have to act like a stick.

And so they spend their time eating and feeding, but they'll also spend their time just standing still to avoid predation.

Stick insects, like all insects, have six legs, but it would look really weird for a branch to have six legs.

So they'll actually, when they're at rest, they'll stick their front two legs out in front of them to look more vertical and look more like a stick.

♪ Narrator: Stick insects are so adept at hiding that it can be hard for them to find each other.

Since they can't see potential mates, they send out a signal of pheromones.

And even when mating, they stay stick still.

Gavin: Not many of them have any sort of defense mechanisms other than a few of them have, like, these nasty spines.

Others have some chemical defense.

But really, they're--they're like tree hot dogs for other vertebrate animals to hunt and eat.

And if you find a really big stick insect, I mean, that's a good day for a monkey or a bird.

So, they're really dependent on being the most convincing sticks that they can be.

Narrator: Stick insects are an extreme example of the seemingly limitless innovation of bugs.

But the bizarre bodies and behaviors that make them so successful don't always endear them to humans.

Ummat: Insects evoke a lot of emotion in people, and usually it's negative.

Partially, it's because people don't like the way they crawl or that sometimes they get bit or stung.

Or maybe it's just because they don't understand them.

But once you pull out a magnifying glass, or maybe a macro lens, you'll see a kaleidoscope of color.

You'll see multiple mouth parts.

You'll see different types of appendages.

You'll see interesting behaviors.

Suddenly this world opens up to you that is happening in miniature.

[bird calls] Dara: I'm in town, guys.

Come out.

[Man chuckles] What?

That's so rude.

Narrator: Turning a lens on this miniature world is how one man hopes to bring focus to the planet's unnoticed heroes.

Lauren: Look at this insect.

[Sound of soft clicking] Nice.

♪ Dara: People come to Costa Rica to see sloths, to see monkeys, to see hummingbirds.

But I'm here to see the bugs, which is an untapped world.

Insects are the foundation of everything in nature.

Right now, I'm in the Cloud Forest, and it's--it's surreal.

It rains here a lot.

And it's got mountains, it's got the clouds coming in.

And it's got a lot of crawly things around, which I love.

Narrator: Getting people to love crawly creatures isn't easy.

Dara Ojo is on a mission to change people's perception of bugs, using the same tool he used on himself, macrophotography.

Dara: I grew up in Lagos, Nigeria.

As a kid, I was not interested in insects so much because I got stung a few times.

In 2020, during COVID, I wanted to pick up a hobby, so I started taking pictures.

So, a friend referred me to take pictures of insects.

I knew nothing about photography.

[Camera shutter clicks] Dara: So, I started watching YouTube videos and then just practicing, failing, practicing, failing.

So it's basically self-taught.

Narrator: With the click of a shutter, Dara brings bugs into human scale.

[Camera shutter clicks] Dara: Nice shot.

You got it?

Yes.

Dara, voice-over: When I look at insects close up, they have a lot of character.

Dara: Pure beauty.

Dara, voice-over: Sometimes they could look grumpy, sometimes they could look happy.

Sometimes they can be staring at you, curious that: "What is this?

Is this person a food or is this a predator?"

When you take pictures of bugs using the macro lens, it brings out that hidden world that people just walk past.

So, bringing those photos to life is one of the things that motivate me.

Dara: Is that like a nest for leafcutters?

Wow.

Lauren: When they feel vibrations of people walking around, the big ants, the soldiers, they get out to attack.

Dara: Before coming to Costa Rica, I wanted to see the leafcutter ant.

And seeing them in nature was surreal.

I've never seen so much coordination in my life.

It was beautiful to see.

♪ If humans could be this coordinated, we would have a better world.

♪ Dara: This is a soldier ant, protecting the colony of the leafcutter ant.

It just keeps moving.

Stop moving, though.

Dara, voice-over: Insects are not the perfect models because you have to wait for the insect to trust you enough around it, so it's not running away.

Dara: God.

Just wait while I focus.

Stop moving, though.

[Chuckles] Dara, voice-over: Then it might just get curious, and that's when you can get the perfect photo because it's staring right into your camera.

There you go.

Continue doing whatever you were doing.

Dara, voice-over: I used to have phobia for insects, so shooting them has been able to make me appreciate them more.

Dara: Ooh!

Look at this beautiful guy!

Dara, voice-over: And I just watch insects and see how they act, protecting their eggs, like, trying to hunt for food, like we all do to try and find our daily needs.

It's just another world, but they're very similar to us humans.

Dara: Let's check out some more on here, man.

Lauren: It's picking up a bit.

Dara: Yeah, Saturday night party.

Oh, wow, so gorgeous.

There you go.

Dara, voice-over: In the last 48 hours, I think I have had five hours of sleep.

The adrenaline in my system to be here, is keeping me up.

♪ Dara: Come see this shot, Lauren.

Nice.

Ohh.

Lovely shot, man.

Dara: Mm-hmm.

Beautiful work.

Narrator: Dara hopes his insect portraits will help everyday people fall for bugs, and feel a connection to what we're losing with ongoing insect declines.

Dara, voice-over: Insect decline is very serious now, so I feel people need to wake up to the fact that if it declines further, we will be in big trouble.

[Camera shutter clicks] My macrophotography has been able to show people what these things look like.

[Camera shutter clicks] The venue for my photos is on Instagram.

That means the picture can spread to other people, so that just keeps multiplying, and people will appreciate insects more.

Dara: Yeah, this small thing is beautiful.

Dara, voice-over: Because making small things look big is something that people really appreciate.

[Camera shutter clicks] And just like people respect lions and tigers, the same thing with insects.

[Camera shutter clicks rapidly] And I think that's spreading the gospel in its own little way.

Narrator: The colors and ornate features Dara captures are the result of infinite adaptations that have helped insects survive in their natural environments.

But as humans reshape the planet, some will continue to adapt and others will die.

And these veterans of Earth's past are now facing a strange new world.

♪ Sylvana: If you think about how long Earth has been around and even the history of insects, they've been around for hundreds of millions of years.

Then think about when cities arrived and then cities as we know them, it's less than a blink of an eye.

Urban insects are interesting because they're finding a way to live amongst the humans and the way that we've manipulated the earth in a way that they've never been used to, the way their ancestors have not prepared for.

♪ [Birds chirp] Narrator: In most major cities, a phenomenon called an urban heat island traps heat in the city center, creating a much hotter environment than surrounding natural areas.

Sylvana: Now we're seeing that in insects and wildlife in the city, this new environment is causing them to have new behaviors and change the way that they find food, change the way that they find mates, and change the way that they raise their young.

Cool, cool.

Narrator: To understand how insects are adapting to these hot, modern environments, Sylvana Ross is on the hunt for a tiny test subject-- Tapinoma sessile, the odorous house ant.

Sylvana: Most people have probably encountered Tapinoma sessile without even really knowing that that's what that ant is.

♪ Sylvana: Also known as the sugar ant because they do really well amongst humans because they really like sugary liquid and sweet things to eat.

I'm actually gonna go see over this big pile.

Anytime I, like, lift up a log or anything, I look for--Ooh.

Uh-oh.

We got ants!

Hold on.

When that happens, I gotta be like--oh, my gosh!

So, I actually look for scurrying.

Like, I look for little, tiny things that are moving around.

These guys do look like Tapinoma.

So, when I lift it up and I see the scurrying, I grab my aspirator and suck 'em up.

Oh, yeah.

♪ Ants do so many different ecosystem services.

One of the major ones is that they're ecosystem engineers.

There are ants that spend their entire lives in the tree canopy and are arboreal ants, and so they're able to fill these different niches.

An ant colony is made up of majority of female workers.

They use pheromones and they use vibrations and touch in order to talk to each other.

They're able to tell each other warnings if there's predators around.

They're able to communicate where there's good food.

And one ant in and of itself can't survive on its own, but an ant with a thousand sisters can then change an ecosystem.

There's a piece of mesh right there, so nothing gets in my mouth, but there's nothing in here, so the ants can, like, shoot down through there.

So, as I put this in my mouth, if I see anything running or scurrying, they just get, like, inhaled into the tube.

♪ Sylvana: There are some places in cities that are a lot hotter than others, and we can see that in neighborhoods that lack the resources to have green spaces and parks.

This is colony 85.

And there's historic reasons why we've broken up our neighborhoods.

Narrator: Across the United States, the practice of redlining in the 1930s determined which neighborhoods of a city would constitute a high risk for a housing loan.

Affluent neighborhoods with low risk were labeled A and B.

Those with majority Black or immigrant populations were labeled C and D and colored red.

Those designations continue to dictate the ecosystems of these neighborhoods today.

Sylvana: And so, those lower-income Black neighborhoods that have been segregated in the past lost a lot of financial resources.

They have more concrete and asphalt.

They have less green spaces, less parks, less tree cover, and so those areas tend to be a lot hotter.

Dumpsters are a good spot.

[Laughs] I know it's kind of gross.

If you were to look at a 1930s redlining map and then compare it to temperature data today, we can see that the neighborhoods that were graded as hazardous and colored red are also the hottest areas of our city today.

Not ants.

In Baltimore, I am picking eight different neighborhoods, two of each graded from redlining.

And I'll be going looking for Tapinoma in each of those neighborhoods.

What's really interesting about the odorous house ant is that populations in natural areas tend to be a lot smaller.

Their colonies are made up of only one to a few queens.

Their workers are only a couple hundred.

I mean, their whole colony might live in an acorn or under a small rock.

But when we see Tapinoma out in the city, her colonies can be ginormous, and I'm talking hundreds of queens, millions of workers, and something about the city is causing that change.

Whether that's because we've eliminated their competition, or is it because we provide them sugary liquids in our trash and in our homes that can give them more energy and resources to have larger colonies?

The ants that are living in neighborhoods that have more concrete and asphalt and hotter temperatures have had to adapt to this really strong selection pressure.

So, I can compare ants from A-graded neighborhoods to ants in D-graded neighborhoods and see what temperature that they can withstand.

♪ My hypothesis is that ants from D- and C-graded neighborhoods will be able to withstand higher temperatures than those in A- and B-graded and also especially natural areas.

For this round of assays, we actually have two colonies, one from a C-graded and one from a D-graded neighborhood, and then we have a colony from our natural state park.

I take a little ant, and I put them in a dry block, and I crank up the temperature in intervals so I can check to see at what temperature that ant loses their muscle function.

Oh, yep.

So, this one, like, she's on her back, and if I give her a little tap, she can't flip back over.

And so I can compare that temperature across ants from different neighborhoods, and I can see if ants from really hot neighborhoods have a higher thermal tolerance than those from cooler, more shaded neighborhoods.

Now we're at 46.8, which is 116 degrees Fahrenheit.

And the only girls left are city ants-- seven, eight, and one, so one from a D-graded and two from a C-graded neighborhood.

Then I can look at their DNA and compare their DNA and gene expression across these different neighborhoods to see if there's internal mechanisms that they're using to tolerate these really hot temperatures.

These are the ants I got from the state park, and then these are all my city ants.

And so the ones living in the city can withstand higher temperatures than those living in the natural area.

I mean, this is really cool, and it's really exciting.

Narrator: First results show that some ants may be tough enough to adapt to a warming planet, but for Sylvana, it will take time to answer her questions about how they're doing it, and what it means for other animals in the ecosystem.

Sylvana: When you see your hypothesis come to fruition, it's very validating, but it's also scary because you understand that humans are changing the environment so much.

And so, this really tiny ant, if it's being impacted by these hot temperatures, what does that say about the birds that are living in hot areas and the reptiles, and even the people that are exposed to these hotter temperatures?

And if racial segregation is creating these really hot neighborhoods and those really hot neighborhoods can impact evolution in ants, it can be impacting entire ecosystems and all these other organisms that we see in cities.

Narrator: As the planet continues to change, some bugs will be evolutionary winners, while others are already losing out.

[Buzzing] Narrator: Even in the most remote places on the planet, insects are feeling the heat.

It's threatening our way of life and some very ancient relationships.

[Man whistles] Dino: Humans and honey bees have a long history, a shared history together.

Humans and honey bees have actually co-evolved many aspects of our behavior, our interaction, our culture, and even our communication.

[Man whistles] [Men shout in Hadza language] Dino: And this is especially true here in Africa.

♪ Human ancestors have gathered wild honey as one of the most important sources of nutrition.

And a testament to this deep relationship between humans and honey bees is the relationship with a third species, the honeyguide.

[Man shouts in Hadza language] ♪ [Man whistling] ♪ [Man speaking Hadza] [Group speaking in Hadza language] [Man whistling] ♪ [Alaitetei speaking Hadza language] [Man whistling] [Group speaking in Hadza language] [Man whistling] Narrator: The Hadzabe are the world's oldest hunter-gatherer people with a unique way of life.

Instead of raising crops, they rely solely on what the forest provides.

[Whistling continues] Narrator: And one of their most important sources of calories is produced by honey bees.

[Man shouts in Hadza language] [Alaitetei speaking Hadza language] [Man shouts in Hadza language] [High-pitched whistle] [Men whistling] ♪ ♪ [Conversations in Hadza language] ♪ [Man speaking Hadza language] ♪ ♪ [Group speaking Hadza] [Alaitetei speaking Hadza language] [Men whistling, shouting in Hadza language] [Man speaking Hadza language] [Man whistling] ♪ Gavin: Bringing home the importance of insects to everyone is a challenge because, culturally, we've not appreciated them as really important aspects of the environment... ♪ but the reality is that they're not just important, they have to exist for humans to exist in the way that we are existing now because we depend on them, where it's this fundamental part of how the ecosystem operates.

If they're not in that ecosystem, that will change our way of life as we know it.

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