Tiny Dracula Ants Set Record For The Fastest-Known Animal Movement

Pesky as they may be, ants are truly incredible insects. The tiny creatures can survive floods by joining together to morph into living rafts, predict earthquakes, lift up to 20 times their body weight, and even select the best tool to complete a job efficiently. Now, it appears that the elusive Dracula ant (Mystrium camillae) can snap its jaws shut at a mind-boggling speed of 90 meters per second (more than 200 miles per hour) – the fastest-known animal movement on record.

“They’re cruising around underground and if they encounter something like a centipede or a termite they can smack them with the mandibles to kill or stun them,” said Andrew Suarez, an animal biology professor at the University of Illinois, who led the study. “They can then sting it to further incapacitate it, and then they carry it back to the nest.”

Endemic to the tropics of Africa, Asia, and Australia, Dracula ants spend much of their time underground or on tree trunks, making them hard to study. The insects get their name due to their unique feeding habits, which involves a form of non-destructive parental cannibalism. The adult ants, unable to process solid food, feed their prey to their larvae. They then chew holes in the larvae and suck the blood. Though this arrangement, which researchers refer to as a “social stomach,” does leave the larvae with holes, it does not harm them.

Suarez managed to collect a few of the ants in Borneo in 2014 and bring them to the University of Illinois for a detailed study. However, when he and Fredrick Larabee, an entomologist at the Smithsonian Natural History Museum, tried to observe the specimens using the lab’s cameras, they realized they were not powerful enough to capture the swift action of the ants’ mandibles. “The ants were so fast that we could not slow their motion down with the cameras we had,” said Larabee. “That’s when we knew we were onto something special.”

So, the researchers made their way to Duke University in North Carolina, to try to capture the speed of the ants’ jaws using the institution’s high-speed camera, which can record up to one million frames per second, ten times faster than the one in Illinois. The team also used X-ray imaging to capture the movement in 3D and conducted several computer simulations to test how the mandible shapes of different Dracula ants affect their snapping abilities.

The results of the study, published in the journal Royal Society Open Science on November 13, 2018, revealed that the tiny insect’s incredible jaw speed, which is attained in 0.000015 seconds – three times faster than that of the previous record holder, the trap-jaw ant – was due to its unique mandibles. Suarez explains, “Instead of using three different parts for the spring, latch, and lever arm, all three are combined in the mandible.”

Also, unlike the trap-jaw ant, Dracula ants do not snap their jaws shut from an open position. Instead, they press the tips of their mandibles together to create a force which transforms one of the mandibles into a spring. The explosive motion is powerful enough to stun and kill prey.

The researchers next plan to study the Dracula ants in their natural habitat. "Their biology, how they capture prey and defend their nests, is still in need of description," says study co-author Adrian A. Smith, of the North Carolina Museum of Natural Sciences and North Carolina State University, Raleigh. The scientists also hope to keep using Duke’s ultra-high-speed camera to find more record-breaking insects. “I think some of these termites are probably just as fast if not faster as these snap jaw Dracula ants,” says Larabee. “That’s what makes biology cool, because there are so many animals out there that we know virtually nothing about.”

Resources: phys.org,smithsonianmag.com,guardian.com