Trap-jaw ants have large mandibles that spring shut incredibly quickly, at speeds above 130 mph, generating a force 300 times greater than their body weight. They've adapted this ability to escape in times of danger; by snapping their jaws shut on the ground, they can fling themselves backward, which is useful for escaping ant lions and other predators.
Magdalena Sorger, an evolutionary biologist at North Carolina State University, was eager to learn more about this unique ability when she began studying trap-jaw ants in Sarawak, Borneo, in 2011. But when she began to collect a nest of Odontomachus rixosus, a trap-jaw ant native to the region, she saw the insect do something nobody had ever recorded: It jumped forward, using its legs.
That was pretty weird, since these ants, relative to others, have been pretty well studied, Sorger says. And prior to this, only three ant genera (the taxonomic grouping above species) were known to jump.
"I thought, Whoa. Did I really just see that?" Sorger filmed what she saw to prove to others that she hadn't just imagined it and published the results of her observations in a study released December 1 in the journal Frontiers in Ecology and the Environment.
The four different genera of ants that can jump (including Odontomachus) are not closely related, meaning that the ability has evolved separately four times, and they likely employ different mechanics, Sorger says. It will be fascinating to learn more about how the different ants jump, which could have applications in biomechanics and beyond, she adds.
Andrew Suarez, a researcher at the University of Illinois who wasn't involved in the paper, says he finds it fascinating that an ant can jump forward and backward in different ways. The forward-jumping ability appears to be quite carefully controlled and involves four legs. That's quite a contrast with the jaw-flinging ability, which is powerful yet uncontrolled, akin to "slamming your face into something so hard you bounce backward," he says.
The ants apparently use the forward jumping only when disturbed, to quickly navigate the complex leaf-litter environments where they live, Sorger says. But she plans to study the species further in the future; it's possible they may also use it to hunt for prey, as some other species of ants do, leaping like jumping spiders upon smaller, unsuspecting insects.
The study was also a reminder to Sorger that "we know very little about insects and the natural world in general," she says.
