DRACULA ANTS GET their name for the way they sometimes drink the blood of their own young. But this week, the insects have earned a new claim to fame.
Dracula ants of the species Mystrium camillae can snap their jaws together so fast, you could fit 5,000 strikes into the time it takes us to blink an eye.
This means the blood-suckers wield the fastest known movement in nature, according to a study published this week in the journal Royal Society Open Science.
Interestingly, the ants produce their record-breaking snaps simply by pressing their jaws together so hard that they bend. This stores energy in one of the jaws, like a spring, until it slides past the other and lashes out with extraordinary speed and force—reaching a maximum velocity of over 321 kilometres per hour.
It’s kind of like what happens when you snap your fingers, only 1,000 times faster.
The jaw of a Dracula ant goes from 0 to 321 kilometres per hour in 0.000015 seconds.
Not only is the Dracula ant’s snap faster than other similar movements, such as the strike of a mantis shrimp or the leap of a froghopper, but it’s also simpler, says Fredrick Larabee, an entomologist at the Smithsonian Institution at the National Museum of Natural History and lead author of the study.
That's because other animals seem to power rapidly moving appendages through a series of separate latches, springs, and triggers.
“In this Dracula snapping ant, the spring and the latch are on the appendage that’s accelerating itself,” says Larabee.
You are what you eat
Before this study, the fastest animal movement record went to a species of trap-jaw ant, which holds its mandibles wide open and then relies on tiny, pressure-sensitive hairs to tell it when to close.
These ants can even use their spring-loaded jaws to escape from predators, like the antlion.
“Trap-jaw ants tend to be sit-and-wait predators,” says Larabee. And a bear trap-like mouth works well for capturing other fast animals as they scuttle across the open spaces of the forest floor.
But Dracula ants are much more secretive predators. They prefer to hunt under the leaf litter or in subterranean tunnels, places where a large, open-jawed approach might not be all that effective.
At night grey reef sharks hunt as a pack in the south channel of Fakarava Atoll, in the Tuamotu Archipelago in French Polynesia. Photographer Laurent Ballesta’s team, diving without cages or weapons, counted 700 sharks.
PHOTOGRAPH BY LAURENT BALLESTA
Interestingly, some termites in the genus Termes pack a punch that is very similar in nature to the Dracula ants. While ants and termites aren’t all that closely related, this sort of co-evolution toward snap-powered strikes might make sense given that termites, too, do most of their battling in tight spaces.
There’s also evidence that this species of Dracula ant likes to hunt centipedes, which are themselves armed with chemical weaponry. It may be, then, that the Dracula ants need these rapid, powerful strikes in order to subdue their food before it can fight back.
“Of course, this is entirely speculation,” says Larabee.
King for a day
“I study high-speed motions in insects,” says Gregory Sutton, a biologist at the University of Lincoln in the United Kingdom. “I generally do insect jumping, so I see this ant work as spectacularly interesting stuff and very important for my own research.”
What’s really exciting, says Sutton, is that we know exactly where the energy is being stored as the jaw bends. “In a lot of these systems, we’re not sure exactly where the latch is,” he says, because they’re often internal.
Think about the mechanisms that allow a flea or grasshopper to catapult itself into the air—much of that magic is hidden inside of the animal’s body, which makes it extremely difficult to study it as it works in nature. But with the Dracula ant, everything is happening externally as the jaws bend, which is what has allowed Larabee and his coauthors to measure these forces so precisely.
But is it truly the fastest movement in nature?
Sutton says speed is relative and can be defined in many different ways, from maximum velocity to acceleration. Fungi can release spores at vanishingly fast speeds, and the nematocyst cells responsible for a jellyfish’s sting explode on the scale of nanoseconds. Then there are Peregrine falcons, commonly recognised as the fastest animal, as they can reach speeds well over 321 kph while diving.
“But from the point of view of the insect limb behaviors—an insect moving a bit of its body—I don’t know of anything faster than 90 metres per second,” says Sutton (which is how fast these ants move their jaws). “So from my point of view, who’s fastest is less important than generating another example of how to do this. How many ways are there to skin this cat, so to speak?”
In any event, Larabee is not optimistic that the record will stand for long.
“I think some of these termites are probably just as fast if not faster as these snap jaw Dracula ants,” he says.
“That’s what makes biology cool,” says Larabee, “because there are so many animals out there that we know virtually nothing about.”