Trap-jaw ants normally use their jaws to jump, but scientists have found a trap-jaw ant species that launches itself into the air with its legs.
In 2011, Magdalena Sorger – author of the study and a recent Ph.D. graduate at North Carolina State University – noticed the ants’ odd behaviour as she and a field assistant were collecting trap-jaw ants in Borneo, the third largest island in the world located in the Malay Archipelago.
According to Sorger, Odontomachus rixosus – a widely distributed forest trap-jaw ant species – typically use their powerful jaws to jump and propel themselves backward. However, when Sorger saw the ants they were doing something quite unusual: they were jumping forward, she stated.
Ants jumping with their legs are extremely rare since only three of the 326 ant genera are known to use their legs to jump. Sorger says that as she was collecting the trap-jaw ants in Borneo, she saw them jumping almost every time.
Other ant species use their legs to form bridges and living rafts to cross obstacles, some use their legs as rudders to navigate through the air as they jump from trees, some ant species are good swimmers, and so on.
In 2013, Sorger returned to Borneo to further analyse the ants’ odd behaviour and found that they jumped not because it made it easier for them to move through the environment (as Sorger previously thought), but rather because they wanted to escape a potential threat.
Whenever Sorger touched the ants’ legs, they automatically started jumping. Leg-jumping was a lot more advantageous than the jaw jumps, because the trap-jaw ants could have a lot more control over their actions and they were propelled forward, rather than backward.
The other three groups of jumping ants all have something in common and that is large eyes, compared with the trap-jaw ants that do not have that feature. Ants in one of the three groups use the jumps, as well as their high vision, to catch prey, but the same cannot be said about the trap-jaw ants, according to Sorger.
Sorger says that further research will show whether trap-jaw ants jump with their legs to hunt for prey, or whether they use those jumps as a defence mechanism.
The research was published December 1 in the journal Frontiers in Ecology and the Environment.
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