If you're a trap-jaw ant, a solid escape plan is everything.
According to a new study published today in the journal PLOS ONE, some trap-jaw ants don't just use their powerful jaws to kill. Like a tiny catapult, they can harness the force of their spring-loaded mandibles to fling themselves to safety, too.
The researchers found that the ant's canny maneuvering doubled its chances of survival in the face of imminent death when other escape methods failed.
The study, conducted by Andrew Suarez and Fredrick Larabee at the University of Illinois, advances scientific understanding of adaptive escape behaviour in some animals by demonstrating that a trap-jaw ant trait that existed for one purpose has adapted for a different purpose.
"The new study verifies that the mandibles do in fact aid the ants' survival by allowing them to eject themselves from a dangerous predicament," Larabee said.
Previously, scientists had appreciated the trap-jaw ant for its fierce jaws—capable of whipping shut at speeds of more than 144 kilometers per hour—to instantly maim a prey insect or an enemy ant. The jaws were also observed performing more routine tasks such as digging nests or tending to eggs and larvae.
According to Larabee, jaw-jumping behaviour has been observed in a range of organisms for more than 100 years—but this study demonstrates a secondary use of mandibles for escape purposes.
"The trap-jaw ant's escape behaviour has actually improved survival in this context," Larabee said. "Evolution has selected this. It's an adaptation."
Ants are among the most diverse and successful organisms in terrestrial ecosystem and include more than 12,000 known species. Larabee first became curious about the interaction between trap-jaw ants and antlions while in central Florida working on another ant research project.
Hanging out at the research center, he grew fascinated by small pits in the sand that antlions had built across the property. Watching the antlions bury themselves at the bottom of their pits to for their victims became a form of entertainment.
"Antlions are indiscriminate. They'll eat anything that falls into their pit, or, at least try to," Larabee said. "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."
The antlion can sometimes employ a second strategy of hurling sand at the ant, prompting a tiny avalanche that causes the walls of the sand pit to fall away. Prey that can't eject itself from the sand pit falls into where the antlion has been waiting all along to snatch and eat it.
While Larabee is reluctant to speculate about what lessons humans can take from the savvy and skill of an entrapped trap-jaw ant, he offers this observation: "As long as there have been animals, there have been animals who want to eat them."
Surviving attempted murder by an antlion affords the trap-jaw ant a range of opportunities beyond immediate survival, he said.
"They can live longer, contribute more and make more babies," Larabee explained. Not bad.