See How Ants Pole Vault With Jaws to Cheat Death

When they are not decapitating prey with their spring-loaded jaws, the trap-jaw ants use their endowments to escape from predators.

A University of Illinois graduate student established that the ants literally make a leap of faith when they flee from antlion pits using their mandibles.

"If an ant falls into the pit, it tries to run away, but the sand crumbles beneath its feet. This pulls it closer to the center of the pit where the antlion is waiting," said Fredrick Larabee who conducted the researchers with others at the university.

When the ant is unable to escape on its feet, it vaults itself using its jaws as the pole.

"It was unknown whether this behavior was meant to help them get away from a predator, and it wasn't clear that it actually improved their odds of surviving an encounter with a predator," Larabee said.

To test his hypothesis Larabee created several antlion sand pits in the lab and placed ants in them. He found that while in most cases ants ran away, some used their jaws to catapult out of the situation.

"The ants were able to jump out of the pits about 15 percent of the time in their encounters with antlions. But when we glued their mandibles shut before dropping them in the pits, they couldn't jump at all. It cut their survival rate in half," he said.

"Based on our earlier studies, if the ant was striking a prey object, the distance between the ant and the prey was about the length of the trigger hairs that come off the mandibles. But when they were jumping off a surface, you would often see the ants put their entire face against the surface, and it was more of a pushing behavior than a striking behaviour," said Andrew Suarez, head of Animal Biology department at the university.