Ants snap jaws, shoot skyward, escape death

trap-jaw ant

EMERGENCY JAWS  A new test quantifies the death-defying value of trap jaws (shown on Odontomachus brunneus).

F.J. Larabee and A.V. Suarez/PLOS ONE 2015

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Jaws that snap shut at 216 kilometers per hour aren’t just for eating.  Trap-jaw ants, which carry such high-powered mouthparts, can snap them against the ground and send themselves hurtling high in the air to safety. The launch technique roughly doubles the ants’ chances of surviving a tumble into predators’ killing pits.

In a test of jaw-powered escape from predators, two University of Illinois entomologists let ants fall into sandpits excavated by a Florida species of ant lion. These predators wriggle themselves into sand at the bottom of their pits, waiting to suck liquefied innards out of  prey that can’t scramble up sandy slopes. Out of 76 Odontomachus brunneus trap-jaw ants that fell into the pits, 49 (64 percent) climbed or launched themselves airborne to escape. When researchers fastened the ants’ trap jaws shut, only 28 percent survived, Fredrick Larabee and Andrew Suarez report May 13 in PLOS ONE.

Trap jaws evolved independently at least four times among ants. The super snap lets ants grab fast or toxic prey, or defend the nest, by knocking invaders into irrelevance. In 2006, researchers proposed that what had been largely ignored as accidental self-launchings could be handy for escaping from the ants’ own predators. The new study shows just how handy rocket-powered mouthparts can be.

UP AND AWAY  A trap-jaw ant launches itself from a hidden killer’s pit. Credit: PLOS Media.

Susan Milius

Susan Milius is the life sciences writer, covering organismal biology and evolution, and has a special passion for plants, fungi and invertebrates. She studied biology and English literature.

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