In the tropics of Africa, Asia and Australia dwells an elusive genus of ant known as the Dracula ant, so called because its adult members feed on the blood of their larvae. The insects spend most of their time scurrying underground or in tree trunks, so they are difficult to study. But as Douglas Quenqua reports for the New York Times, researchers were recently able to take a closer look at how one species of Dracula ant wields its powerful mandibles—and in doing so they have revealed that this tiny critter boasts the fastest known appendage of any animal.
Andrew Suarez, an animal biology and entomology professor at the University of Illinois, managed to collect specimens of the Mystrium camillae species in Borneo in 2014. He and his colleagues—among them Fredrick Larabee, an entomologist at the Smithsonian Natural History Museum—examined the ants at Duke University, using a remarkably fast camera that can capture up to one million frames per second. The team also used X-ray imaging to study the insects’ anatomy in three dimensions, and conducted computer simulations to show how the mandible shape of different Dracula ant castes affects their snapping power.
The results of the team’s investigation, published in Royal Society Open Science, showed that Mystrium camillae can snap its mandibles at a speed of up to 90 meters per second (more than 200 miles per hour). That’s 5,000 times faster than the blink of an eye, and three times faster than the mandible-snapping speed of the trap-jaw ant, previously the fastest insect known to scientists. It takes only 0.000015 seconds for the jaws of the Dracula ant to accelerate to their maximum speed.
Dracula ants boast unique mandibles, “[e]ven among ants that power-amplify their jaws,” Suarez explains. “Instead of using three different parts for the spring, latch and lever arm, all three are combined in the mandible.” And unlike the trap-jaw ant, for instance, Dracula ants don’t snap their jaws shut from an open position. When gearing up into snapping action, the insects rub the tips of their mandibles together, creating stresses that release when one mandible slides over the other—not unlike the snapping of a human finger.
The force generated by this action is so great that it can stun or kill prey, which the ants then feed to their larvae. According to Hannah Devlin of the Guardian, adult Dracula ants cannot eat solid foods, so they survive by feasting on the blood of their well-fed young. This behavior is known as “non-destructive parental cannibalism” because it doesn’t kill the larvae; it just leaves them “full of holes.”
That said, scientists don’t yet know if Dracula ants evolved their unique jaws for predation or defense purposes. But the new study demonstrates how the insects’ mandibles have adapted to snapping at extremely high speeds. The researchers compared X-ray scans of Mystrium camillae to those of Stigmatomma pallipes, a closely related ant that uses its mandibles to bite—not snap. They found that Dracula ant mandibles are flattened in such a way that allows their jaws to bend and release like a spring.
The new study also shows how improving camera technology is helping scientists study animal speeds with unprecedented accuracy. So while Mystrium camillae is currently the titleholder of the fastest jaw-snapping record, Larabee doubts this blood-sucking species will reign supreme for long.
“There are a lot of other Mystrium species and there are a lot of other termites,” he says. “The work on snapping termites is just starting and there’s a lot to learn about how fast they are.”