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Ants are practically everywhere, and some creatures have found it beneficial to blend in with this crowd rather than stick out.

Hosted by: Stefan Chin

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[intro ].

Ants are one of the most abundant organisms on land. They’re found practically everywhere.

But not everything that looks or acts like an ant/is an ant. They’re… ant-posters. Charlat-ants.

Ant mimics. Mimicry is a pretty common ecological phenomenon, and it works in a lot of different ways. Sometimes it’s defensive, sometimes aggressive.

Sometimes it’s all about how you look, and sometimes it’s all about how you act. There are a bunch of different kinds of mimicry, and most of them don’t have hard and fast lines between them. But these creatures have mastered practically all of them -- in order to look like ants.

To start off with, let’s take a look at the jumping spider Myrmarachne. Instead of the usual squat and stout form a jumping spider might take, these little guys have evolved some extreme body modifications. They’ve turned super long and skinny, all the better to mimic an ant.

The males of some species take it even further, evolving mouth-parts large enough to resemble a worker carrying cargo. They’re so big, in fact, that the spider can’t get venom through its fangs anymore. This kind of body modification is impressive, but also not super uncommon when dealing with ant mimics.

There’s even a name for this phenomenon: the Scrabble-winning word myrmecomorphy. As for why this spider would evolve to look like an ant, it’s an example of what researchers call defensive or Batesian mimicry. Ants, though small, can be intimidating.

Various species can be aggressive or bad-tasting, and can come equipped with biting jaws, venomous stingers, or even sprays of acid. And they can use pheromones to summon more ants. Whereas spiders are predators, but they’re not usually well-equipped for defense.

They don’t have armor plating or thousands of nestmates to call on. There are a lot of animals that might think a spider makes a pretty good snack, like birds, wasps, or even other, bigger species of spider. Which means it might be safer to look like an ant than a spider.

These ant-mimicking spiders back up their myrmecomorphy with behavioral mimicry too. They wave their front legs like antennae. They run zig-zag like ants.

They even maintain this ruse when hunting. Instead of leaping at prey, they run up and tap it, like a curious, harmless ant would. Then they strike.

By doing this, they keep themselves safe from those other spiders and birds, who might prefer not to tangle with the whole biting, stinging, swarming ant business. There are species of katydids and cicada-like insects called planthoppers with similar strategies. But those are still arthropods.

Much stranger are the plants that have been hypothesized to mimic ants in a similar way. We know that some plants mimic insects, like the bee orchid that tricks bees into pollinating them. But scientists in Israel have also suggested that dark spots and flecks on plants such as cocklebur and passion flowers might be ant-mimicking defenses against herbivores.

But defensive mimicry isn’t the only way to pretend to be an ant. An interesting possible case of mimicry comes with some species of spider wasps in Australia. Back in 1969, a scientist in Australia was out looking at a bunch of small, metallic blue ants running about in the sand, when he noticed one was walking oddly.

On closer inspection, he also noticed two little nubbins — wings. Or the vestigial remains of wings. Which would be unusual on a worker ant.

And its “waist” didn’t look right either. This wasn’t an ant, it was a wasp. Now, wasps already kind of look like ants — they’re distantly related — but the lack of wings and exact color match made it seem like an almost perfect mimic.

At first blush, you might call this another example of Batesian mimicry — an organism mimicking a more harmful one for defense. But here’s the thing: the wasps aren’t defenseless. They have powerful stingers.

So their mimicry isn’t a bluff to make them seem more dangerous than they already are. There’s another type of mimicry where two harmful species look similar to each other, and both benefit because the overall signal is stronger. It’s called Mullerian mimicry.

It’s like how both wasps and bees carry black-and-yellow warning colors. In this case, the wasp seemed to be sharing Mullerian mimicry with the ant. Either by bite or by sting, predators would learn not to mess with little blue scurrying things.

That said, Mullerian mimicry of ants seems to be mostly limited to… other ants. Evidence of this beyond a handful of possible examples is a bit sparse. So far we’ve seen how spiders, insects, and maybe even plants use ant mimicry to keep themselves safe.

But some mimics don’t just try to pretend to be an ant. They’re out to exploit -- and even eat -- the ones they copy. Consider the somewhat uncreatively named large blue butterfly, a species found throughout Europe.

Like all butterflies, they start their lives as caterpillars. But these caterpillars spend almost no time eating leaves. Only about two weeks after hatching, the caterpillar goes down to the ground and waits to get found by red ants.

The ants, thinking it’s a lost ant grub, take it back to the nest, putting it in with the other grubs. There it gets waited on and fed by the nurse ants, mooching off their food. Some species are more aggressive, feeding on the real ant grubs.

The caterpillars don’t even try to look like ants. Instead, to pull off this con, they use chemical and acoustic mimicry, mimicking the smell of the ants and the sounds of their queens. This is a kind of reproductive mimicry — when mimics exploit the host to aid in their reproduction.

The most famous example is probably the cuckoo, a bird that lays its eggs in other species’ nests. As for what the butterfly gets out of it, ant nests are well-defended, generally free of predators, and have a stable environment. Not a bad place for a squishy little caterpillar to grow up.

Over the course of a year or so, the caterpillar will stay in the nest, growing up big and strong at the expense of its hosts, until it pupates and emerges unharmed as an adult. Another example of mimics flying under the radar are the beetles that evolved to look like ant butts. This beetle, called Nymphister, was only described in 2017.

They get around the forest floor by latching onto an army ant’s butt as they’re moving. Curious researchers noticed that an ant they were observing had… two butts. This may be an example of tactile mimicry.

The beetle feels like the ant. Its size, shape, and shell texture all match the ant, so other workers don’t notice. We’re not sure how the ant doing the carrying feels about it.

And we don’t know why they do this, though there are other piggy-back parasites out there that can use the ants as protection or a way to get to new food sources without doing any work. Army ants are fearsome, with colonies that number in the hundreds of thousands of workers. They nest only temporarily, going out in group raids to capture prey like other ants, insects, and even small vertebrates.

They’re just not something you want to mess with. But for those who can, a colony of army ants can be a resource in disguise. Enter the Aleocharinae, a group of rove beetles.

They’re tricky to find out in the wild. Which could be because you have to go looking for them in swarms of army ants. But they’ve evolved into superlative ant mimics.

Their waists have narrowed, their legs have lengthened, and their antennae have even developed the signature ant “elbow”. They even smell and act like the army ants, going so far as to lick and groom “other” worker ants and even participating in raids. But they’re not there for defense.

When the beetles get hungry, it’s the ants’ hard-won food — or even their young — that the beetles go for. This is known as aggressive mimicry. In aggressive mimicry, the mimic passes itself off as something harmless in order to trick its prey into letting down their guard.

This seems to be a successful strategy for rove beetles in particular. One 2017 analysis found it may have evolved at least 12 different times in different species of rove beetle. But not all aggressive mimics have to change their entire bodies to trick their prey.

Check out this species of crab spider. Found in Thailand, India, and China, adult spiders prey on weaver ant workers. The spider’s strategy is to behave like a dying or struggling worker.

Other workers draw near to see what’s wrong. Then the spider pounces and runs away with its victim. This is another example of aggressive mimicry.

By doing this, the spider can get an easier meal. Finally, remember those jumping spiders that pretended to be ants for defense? One species in particular, the black-footed ant spider, uses its mimicry in an even more interesting way.

Because it might have both Batesian, or defensive mimicry, and aggressive mimicry. It lives around Lake Victoria in Africa, and its preferred diet isn’t ants or bugs. It’s the squishy, nutritious eggs of other jumping spiders.

Problem is, it’s hard to get to the eggs without running afoul of the adult spiders, who could attack the ant spider. But ants will attack and even eat these other jumping spiders, so the spiders have evolved to be able to watch for, recognize, and run away from ants. And the black-footed ant spider has evolved to take advantage of this behavior.

It shows up at its intended spider victim’s nest pretending to be an ant. The other spiders, mistaking it for an ant, will run away, letting the ant spider move in and eat the eggs and young before the other spider realizes it’s been tricked. So the ant spider has Batesian mimicry — the spider’s mimicking a scarier animal in order to not get attacked — but it’s using this trick in order to trick its prey, which would count as aggressive mimicry.

It’s both a defense and an offense, an incredible example of how nuanced mimicry can be. Life has found ways to use mimicry for virtually every application we can imagine. In fact, ant mimicry alone is estimated to have evolved at least 70 times.

In many countries, more than 1 percent of all spiders are ant mimics. If that seems like a lot, well, it’s estimated that ants may account for a quarter of the biomass of animals on our planet. So if you’re looking for a crowd to blend into, ants are a good option.

It’s a big crowd to get lost in. Thanks for watching this episode of SciShow, and thanks to one group of people who don't resemble ants at all, except in the sense that they are both numerous, and stronger in a group. Yes, it's our patrons.

Thanks for everything you do! If you want to get involved, check out patreon.com/scishow. [ outro ].