World’s Most Badass Ant Skydives, Uses Own Head as a Shield

When threatened, Cephalotes ants will leap from a branch and glide themselves right back to the trunk. This little guy was … encouraged to demonstrate.

“Where were you born, in a barn?” my dad used to ask when I left doors wide open. Forget about that being a silly question, on account of him being there when I was born in a hospital. Really, we could have avoided all that heartache in the first place if only we were a family of Cephalotes ants, whose soldiers, no joke, use their heads as doors to seal their colonies from intruders.

With a range stretching from Argentina all the way up into the southern U.S., this incredible genus of ants has also mastered the art of rainforest skydiving, leaping from the canopy to avoid predators, only to steer themselves mid-flight right back onto the trunk of their home tree. And they do it with remarkable agility.

But first: that strange head. The various species of Cephalotes have a range of head shapes. Some are almost perfectly circular, like a manhole cover. These ants typically establish their colonies in dead branches of living trees, where wood-boring beetles have conveniently left cavities. “The size of the soldier head is perfectly matched to the size of the beetles that came out of the tree,” said tropical ecologist Stephen Yanoviak of the University of Louisville.  The Cephalotes move in, and at any given time a soldier’s head serves as a door to keep the ants’ many enemies at bay.

In other species, the soldiers have to team up. Cephalotes atratus, below, occupy the hollow branches of living trees, where a longer slit in the wood acts as an entrance to their colony. “What they’ll do is the soldiers and the workers will line up basically cheek to cheek with that fairly flattened head,” said Yanoviak. “And they can collectively block the entrance that way.”

Ants of the Cephalotes genus have enlarged noggins that they use as doors to block the entrances to their colonies. Here, Cephalotes atratus ants close the door right in their comrade’s face. Hope you’ve got a sleeping bag, pal.

But there’s no such thing as a perfect defense. And individual ants can find themselves isolated and defenseless outside the colony. For that, the Cephalotes have developed a leap of faith.

You Are the Wind Beneath My Sclerotized Exoskeleton

Plenty of rainforest critters engage in what’s known as directed aerial descent, essentially a controlled fall. Some snakes do it. Frogs and lizards too. But the Cephalotes and a handful of other ant genera are the first arthropods known to glide to escape predation or, say, an ungainly monkey rambling through.

Studying this sublime behavior is Yanoviak, who, I’m willing to bet, is one of the few people on Earth who has sat in a tree, painted ants white, and flung them off — and gotten paid for it. But through this work he’s found that a staggering 95 percent of the Cephalotes ants he drops will glide over to the trunk and find their way right back up to the nest.

Here’s how they do it. Once airborne, the ants splay their legs out and look for the trunk of the tree. “We did some experiments to show they’re actually targeting the light-colored tree trunks,” said Yanoviak. “We think of tree trunks as brown and kind of dark, but actually in the tropical rainforest they’re bright white because they’re covered with a special species of lichen that makes them reflect very brightly relative to the background.”

By simply moving their legs, the ants can increase or decrease drag in order to change direction, just like a skydiver … with more legs. And if they don’t like their heading, they can correct themselves incredibly quickly. “I’ve seen ants start gliding towards a bright patch of sunlight on a leaf,” said Yanoviak. “And they’ll get maybe half a meter from it and in a split second they’ll change direction and head over towards a tree trunk.”

Cephalotes atratus come equipped with spines. When picked up by humans, they’ll roll their heads back to drive the spikes into skin. This causes an itchy, painful sensation, which may be due to alarm pheromones secreted by the ant. But we won’t know for sure until someone locks a Ph.D. student in a room with a whole lot of Cephalotes atratus ants.

Coming in for a hard landing on vertical surface, though, is damn tricky. Yanoviak has seen ants slam into the tree trunk and bounce off, only to glide right back for a second go. And they’ll keep bounding down the tree until they finally get a solid grip.

From here, the ants will return to the colony surprisingly fast, finding their way with pheromones and a good visual memory of their surroundings. (Yanoviak once dropped a painted ant out of a tree, and just 10 minutes later saw it walking up a nearby branch.)

But why evolve such piloting skills? It’s not like a fall to the leaf litter below would kill them. They’re too light to suffer serious injury on impact — force, after all, equals mass times acceleration. But it isn’t the impact the ants need to worry about.

At least 10 percent of the Amazon is flooded for three to four months of the year, according to Yanoviak. This, of course, brings hungry fish (and, frustratingly, a hit to the ants’ property values). Yanoviak found in his experiments with Cephalotes atratus that 42 percent of the ants that hit water either drowned or were eaten. And even when hitting the unflooded leaf litter, the ants, far out of their element, must contend with all manner of other predators.

So they glide to avoid the dangers below. Life ain’t exactly carefree in the canopy, of course, but Cephalotes are certainly better equipped to handle foes up there. Except for the ones they never see coming.

Attack of the Butt-Reddening Parasite

In 2005, Yanoviak headed to Panama with the BBC to film these wonderful flying ants. A colleague had actually gone to the rainforest two weeks prior to look for the critters, lest they be left with no stars for the show. Some of the specimens he found, though, had bright-red bums. He reported as much to Yanoviak, who told him that he must have the wrong species.

When Yanoviak arrived, he took the specimens into the lab and broke one of the red ants open. Out spilled a mass of worm eggs. “We discovered a new type of nematode parasite that infects these ants,” he recalls, “and causes only the rear end of the ant to turn bright red.”

To his friends, this ant looks ridiculous. To a bird, it looks delicious. And you know what they say. You can pick your friends, but you can’t pick the predator that’s about to consume you.

Under the influence of the parasite, the ant also becomes markedly sluggish and prone to pop its red booty in the air. Why? Well, Yanoviak has never witnessed it, but he hypothesizes that the nematode is steering its host toward doom.

The redness, he reckons, makes the ant look like a berry, and the behavioral manipulation makes it more conspicuous to passing birds. The exoskeleton also weakens, making the red abdomen easily detachable, perfect for such predators to pluck off and swallow. The bird will then expel the eggs in its droppings, which just so happen to be a favorite food of the Cephalotes ants. While the nematode doesn’t necessarily need the bird’s body to complete its life cycle, this is a brilliantly efficient way to quickly spread yourself around the forest — if you don’t mind a tour of a digestive system first.

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