These four different ants are each ruthless in their own way.

They steal other ants; use their own siblings as storage tanks; fight off huge maggots, and even throw their own babies in the water to survive.

First up is everyone's favorite little friend, the fearsome fire ant.

They're already cranky on a nice day, but when the rain falls ... ...they turn into a living, stinging raft.

This soft mound of dirt is home to some tough insects.

Red fire ants.

They're all over the southern U.S. And if you get too close, you will regret it.

They clamp onto you with their huge jaws.

And then they sting.

Over and over.

Rude.

They inject nasty venom that burns and causes itchy welts to pop up.

And if you think they're scary on land, you're gonna absolutely hate 'em during a flood.

Imagine wading into one of these.

This floating nightmare is made out of thousands of fire ants.

They've escaped their flooded nest by making a raft from their own bodies.

Here's how they pull it off.

As flood water trickles into the tunnels below their mound, fire ants start a rescue mission.

They evacuate the colony's babies - these larvae and pupae - to the surface.

But researchers at Louisiana State University found that instead of putting the babies on the top of the raft, where it's dry, they put them on the bottom.

Listen, these ants have their reasons.

See the halo of hairs on these larvae?

If you look at the raft from below you'll see how those hairs trap air bubbles and hold the larvae together in clusters, you know, like giant floaties.

Those same bubbles help everyone breathe through tiny holes on the sides of their bodies.

And hey, don't feel bad for these ants with their heads dunked underwater.

They'll get their turn on top of the raft eventually.

Workers grab onto each other by the tips of their legs, called tarsi.

Some of them hold onto the larvae, too, and lock legs ... like ant scaffolding.

And then they're ready to set sail, wherever the water may take them.

Ants make these rafts really quickly.

Check out this experiment.

A researcher at Georgia Tech drops a ball of fire ants into the water.

It only takes them two minutes to assemble.

This ability has helped red fire ants spread across the world from South America, where they evolved along the rivers' edge.

Rafts can stay afloat for almost two weeks.

They survive on food they brought in their bellies.

With the whole colony to protect, workers are extra defensive.

They sting with more venom than usual.

Not a good time to run into them.

When the water recedes, they'll dig a new nest ... and live their best fire ant life, eating whatever crosses their path and stocking up for their next getaway.

Next up: kidnapper ants.

They steal other ants' babies.

But why?

These ants are planning a heist.

They don't have a choice.

They can't feed themselves on their own.

But they're not plotting to steal food.

They steal other ants.

They're kidnappers.

As the sun sets in California's Sierra Nevada mountains, scouts leave their underground nest.

They're looking for ants of an entirely different species.

This nearby colony of black ants knows what's out there.

So every afternoon, they block the entrance to their own nest to protect themselves.

But it's too late.

A scout spots them.

She rushes back to mobilize her sisters.

They charge out across the forest floor.

It's a raid!

The black ants try to defend themselves from the onslaught.

But it's not enough.

They're overwhelmed, panicked.

The raiders start digging.

[soaring music] [drumming] Once they're in, they know exactly what they're after.

The most prized possession ants have: their young.

[melancholic music] Those white things are pupae - the developing juveniles.

The kidnappers use their pointy, oversized mandibles to snatch them up and haul the young back to their nest.

Now, you'd think when the young ants grow up, they'd realize they're surrounded by strangers ... ... in the nest of a totally different species.

But ants don't really recognize each other by sight.

They use smell.

So the kidnappers coat the young ants in secretions, imprinting their colony's scent onto the new arrivals.

As they grow up, the young black ants think they're at home, with their own family.

They have no idea.

So the newly enslaved ants just get to work ... ... leaving the nest to forage for food for their captors.

The captive ant's mandibles are serrated for grinding up food.

The kidnapper's jaws are really only good for one thing: grabbing young ants.

They can't even chew their own food.

So the kidnappers get their captives to regurgitate food right into their mouths, kind of like a pre-made smoothie.

It's called trophallaxis.

The captive ants do pretty much all the work in the colony, like keeping up the nest and looking after the young.

So the kidnappers can spend their days just lounging around in a big pile ... until it's time to storm the forest floor again, looking for more unsuspecting ants to join their ranks.

Honeypot ants have an interesting definition of family.

To survive, they turn their own sisters into jugs of delicious nectar.

Deep inside their underground nest, honeypot ants are stuffing their own kin.

The glistening globes hanging from the ceiling are actually part of the ants' bodies.

These portly ants are known as repletes.

The elixir inside them will nourish the colony when food is scarce in the ants' arid homelands in the Southwest and Mexico.

To feed a hungry nestmate, a plump replete opens its mandibles wide and regurgitates a tiny droplet that the other one slurps up.

As the liquid drains, the ant's belly deflates.

The whole thing happens while the replete is hanging by the tips of its legs.

So how do these ants become living storage tanks?

It all starts with this giantess - the queen.

All these workers are her daughters.

She lays thousands of tiny white eggs.

Workers tend to them as they grow into squirming larvae ... ... and then pupae wrapped in fuzzy cocoons.

They choose the biggest newborns to stuff until they swell into repletes.

To fill them up, workers venture out at night to forage.

Dead insects provide protein and fat.

Desert plants give them sweet nectar.

Or dinner might be red artificial nectar, if a human is keeping the ants as pets.

Workers carry the nectar back.

And they feed it, drop by drop, to their sisters, the ones they're turning into repletes.

They make up about one fifth of the colony.

The nectar flows into a pouch called the crop.

The crop will swell into a storage tank because valves prevent most of the liquid from flowing into the stomach, where it would be digested.

As their belly grows, this flexible membrane stretches.

The hard sclerites that protect the ant's abdomen move away from one another, until they end up like a chain of islands on a tiny planet.

Suspending themselves allows the air to circulate around them, maybe preventing a fungi attack.

To our human eyes, these living chandeliers might seem like captives, hanging in the dark for weeks or months.

Or it might look like they have it easy, just chilling while droplets are lovingly delivered.

The truth is that every worker in a colony has a key job.

And all of them, even a replete in its cozy home, can face a sudden demise ... by a badger that digs up the nest ... or someone delighting in a special treat, as humans have done for thousands of years.

Mmm.

These Argentine ants are brave bodyguards, ready to do battle with anyone who threatens the source of their sweet treats.

This orchard is swarming with Argentine ants, but they're not here for the juicy oranges.

They've found something way better.

They're obsessed with these delicate candy ribbons ... ... which happen to be coming out of the butts of these tiny insects.

Asian citrus psyllids.

They suck sap from citrus trees.

And produce the prettiest of poops, called honeydew.

The ants ranch the psyllids like cattle, putting their lives on the line to protect their herd from predators.

This ladybug larva is easily deterred.

But this hoverfly larva takes more convincing.

[frenzied music] Even more dangerous to psyllids is this tiny parasitoid wasp.

It's looking for a host for its eggs.

But the ants are having none of that.

The psyllids and their ant allies have an even bigger threat.

Citrus growers who are desperate to keep the pests out of their orchards.

That's because psyllids can spread bacteria in their saliva that causes a disease called citrus greening.

The disease turns leaves yellow and makes fruit green and bitter.

Citrus growers can spray pesticides, but those kill the helpful insects too ... ... leaving the trees undefended when the psyllids inevitably find their way back.

Plus spraying only gets at some of the ants, since most are safely underground at any one time.

So let's recap.

It's psyllids and their ant bodyguards vs. citrus growers, predators and parasites.

Still with me?

Because psyllids are so tough to get at, citrus growers decided to take out their ant accomplices instead.

By studying the ants' behavior, researchers at the University of California, Riverside, found a weakness they could exploit.

Ants follow the easiest path from tree to tree.

They're all about efficiency.

They turn the orchard's irrigation pipes into mini highways.

Researchers set up sensors on the pipes that use invisible infrared beams to measure how many ants go marching through.

In the most trafficked areas, researchers spread these tiny biodegradable balls.

They're soaked in sugar water laced with a slow-acting insecticide.

The ants slurp up the poison and bring it back to share with the colony.

This targeted technique uses just a fraction of the pesticide that spraying would.

With fewer of their bodyguards around, the psyllids are more exposed to their enemies.

The parasitoid wasp moves right on in.

And lays an egg on the psyllid's soft underside.

That wasp egg hatches and the larva - right here - burrows into the psyllid, devouring it from the inside.

When the wasp is all grown up, it chews its way out, right through the top of the dead psyllid.

Glad they're on our side, huh?

It's a story of unlikely allies, fighting an ongoing battle, for the sweetest of rewards.