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"Long
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August 03, 2010
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Ants’ Olympic jumps caught on tape
Aug. 21, 2006
Courtesy University of Illinois at Urbana-Champaign
and World Science staff
Ants are known for impressive lifting feats. Now, scientists have videotaped other Olympic-style stunts some ants perform—the high jump and long jump.
The new high-speed films were part of an effort to learn how the ants manage to jump up to 40 times their own length sideways, or eight times their own length upward.
A trapjaw ant (Odontomachus bauri)
confronts its hapless prey.
Still from a film of a trap-jaw ant
performing an escape jump. (Courtesy PNAS)
VIDEOS: (Quicktime required, available here.)
The answer is in their jaws, the scientists said: the trap-jaw ants, found in Central and South America, snap
these shut with a speed that marks the world record for fastest-moving body parts.
The force of the clap propels the ants, and sometimes their enemies, through the air.
Andrew V. Suarez of the University of Illinois at Urbana-Champaign and colleagues found that the jaws close 2,300 times faster than an eyeblink,
taking little more than one tenth of a millisecond. Their closing speed
averages about 137 kilometers (85 miles) per hour, the researchers reported.
Their findings are to appear in this week’s early online edition of the
research journal Proceedings of the National Academy of Sciences.
Powered by a large, muscle-filled head, the jaws work like spring-loaded lever arms, Suarez said. They shut so hard, the ants needs an internal mechanism to dampen the blow and keep the jaws from crushing each other.
Trap-jaw ants feed on termites and other ants; their predators include spiders, frogs and lizards.
Depending upon how the ants used their jaws, ants in the study produced power for predation or for two types of “defensive propulsion,†according to the researchers.
In the first, they would simultaneously attack an intruder and bounce away, up to 40 cm (16 inches). That sometimes made the intruder bounce away as well. The second type of movement, the “escape jump,†occurred when a threat was too large. Then, the ant would snap its jaws off the ground, launching itself up to 8 cm (3 inches) in the air.
These behaviors may have evolved because the ant “builds nests in leaf litter, rather than below ground,†the researchers wrote. “Without the subterranean strongholds typical of many ants, temporary escape from predators and ejection of intruders may be essential.â€
The imaging system was capable of capturing 250,000 frames per second, the researchers said, allowing analysis of the jaw movement in unprecedented detail.
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