1In nearly every corner of the earth, ants wage war against each other.
2Their weapons are what nature gave them.
3Some have strong armor, deathly stingers, or sharp mandibles.
4And then there's this tiny and not very impressive ant,
5but it rules the biggest empire any ant has ever built.
6A colony spanning continents and fighting wars that leave millions of casualties.
7Let's take a look at this unlikely warrioress, "Linepithema humile" the Argentine ant.
8This story begins in the floodplains around the Parana River, in South America.
9It's a crowded ant megalopolis where dozens of ant species fight for dominance,
10including fire ants, army ants and the rather unimpressive Argentine ant.
11It measures only 2 to 3 millimeters in length
12and with its small mandibles, it's surprising that it survived among its buff competitors.
13Their homes are equally unremarkable.
14Their colonies range from fairly small to very large and could be found anywhere:
15Under logs, in loose leaf litter or the former colonies of other ants.
16Here, Argentine ants prepare their most effective weapon against their competitors: bodies.
17Most ant species have only one queen to produce ants,
18while Argentine ants went all-in on numbers.
19For every 120 workers there's one queen, laying up to 60 eggs a day.
20So their colonies grow fast and have millions or billions of individuals.
21Teams of queens and workers frequently branch out and found new colonies.
22But this strategy has a downside:
23As colonies grow and produce a lot of offspring,
24mutations occur and new colonies adapt to new environments.
25Their DNA slowly changes from generation to generation and differences accumulate.
26So after a while, the ants that left the colony will become more like distant cousins
27and start to compete with their mother colony.
28In their native South American range, this is how Argentine ants behave.
29Within their colonies they are very cooperative and well-organized,
30but they fight vicious wars against other Argentine ant colonies and other ant species.
31With equally strong opponents on every side,
32the Argentine ant became extremely aggressive, fighting for every inch of ground.
33But it could never dominate its neighbours until humans showed up.
34We did what humans do and transported things around the world by ship.
35On one of them, a few Argentine ant queens hitched a ride as stowaways from South America to Madeira and New Orleans.
36The Argentine ants suddenly found themselves in a strange world.
37Instead of being surrounded by deadly enemies, they found only victims,
38nobody could fight them effectively.
39Because only a few Argentine ant queens were introduced to the outside world,
40the resulting colonies had very low genetic diversity.
41On top of that, the introduced Argentine ants kill up to 90% of their queens every year.
42Fewer queens, less genetic variation.
43So, as these colonies spread across the landscape,
44ants that left the colony were no longer considered distant cousins.
45As a result, the new colonies form not opposing but cooperating parties called "supercolonies".
46This is a very uncommon strategy in the ant kingdom,
47only a few of the 16,000 ant species have evolved supercolonies.
48A supercolony was established on the West coast of the USA
49and became a base for the tiny ants' global conquest.
50Today, the Argentine ant inhabits the Mediterranean zones of six continents and many islands.
51This one supercolony was especially successful,
52establishing sister locations in California, Europe, Japan, New Zealand and Australia,
53forming one massive intercontinental megacolony of Argentine ants.
54This makes them the largest society on Earth, more numerous than even the human one.
55But their success has changed the ecosystems they invaded.
56California is a perfect example of this.
57In their greed for more territory,
58the invading Argentine ants have overrun and replaced 90% of the native ant species,
59including several species of Californian carpenter ants.
60Although carpenter ant workers are giants,
61their colonies have only between 3,000 and 6,000 individuals
62and stand no chance against an expanding supercolony of billions of Argentine ants.
63Argentine ant workers attack by wiping toxic chemicals on their victims
64which irritates the enemy and marks them as a target for other Argentine ants.
65When they attack, the Argentine ants wash over their victims,
66clinging on to their opponents in groups and pulling apart their limbs.
67It doesn't matter how many of them die, there are always more.
68Once the colony is overrun and exterminated,
69the Argentine ants feed on their victims brood and take over their home and territory.
70The Argentine ants' numbers allow them to hunt down and devour such an excessive mass of different insects
71that over time some species disappear from the ants' territory completely.
72Argentine ants don't care about working with the local flora and fauna,
73they consume them and move on.
74And, if their next stop happens to be human property,
75they will rudely make themselves at home there too.
76They forage in dumpsters, bowls of pet food and sneak into kitchens to claim leftovers.
77Not just our homes, our gardens and fields are also impacted by Argentine ants,
78since they tend to hordes of aphids as their cattle.
79The aphids feed from plants and produce a sweet honeydew,
80which they trade with the ants for protection.
81Since the ants have no major enemy to fear in their new homes,
82the aphids thrive and ultimately kill the plants they live on.
83So, on top of being a major disruption for the ecosystems they invade,
84they are also a huge pest for agriculture.
85But the rule of the Argentine ant is being challenged.
86Parts of the super colonies have broken off and become their own empires.
87A merciless civil war has broken out.
88For example, the Lake Hodges Supercolony has been fighting against the Very Large Colony for years in San Diego County.
89A massive war is going on over a dynamic front line stretching over kilometers,
90an estimated 30 million ants die here each year.
91On other fronts, an old acquaintance from the Parana River has risen from the shadows.
92Red imported fire ants, which were accidentally introduced from their old home to the coast of Alabama.
93Not only are the red fire ants fierce fighters and more than able to deal with the Argentine ant,
94they are also able to form super colonies themselves.
95Now the old wars from their distant home have been taken to a foreign battleground.
96In the southeastern US the super colonies clashed fiercely.
97The Argentine ants found themselves outgunned by the fire ants.
98The fire ants major workers are more than twice the size of the Argentine ants and wield venom-injecting stingers,
99even though the Argentine ants fought fiercely, the fire ants were too much for them.
100After countless lost battles,
101the red imported fire ant exterminated the Argentine ants super colony from much of the southeastern US.
102This is one territory lost but the Argentine ants will fight on.
103This amazing network of cooperating super colonies is the biggest success in their history.
104And they'll not give it up because of a small defeat.
105They will stand their ground against any enemy that might arise.
106No matter if it's on the Parana River or on one of the large battlefields across the world.