Maui December 2013 Trip #9
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   Part 9: Maui Ants (2)      Wayne's Word Ant Page        Maui Ants 2012        Pheidole On Owens Peak  

Subfamily Ponerinae: Leptogenys falcigera

Elaine found these remarkable ants along the beach walkway in Wailea. They have large, sickle-like jaws and some are specialized predators on various groups of arthropods. They belong to the same subfamily as the remarkable trap-jaw ants. This species is native to Africa.

Portrait view showing the remarkable jaws of Leptogenys falcigera.

Odontomachus coquereli: Trap-jaw ant native to Madagascar. April Nobile ©

Trap-jaw ants of the genus Odontomachus have a pair of large, straight mandibles capable of opening 180 degrees. The jaws are locked in place by a pair of large contracting muscles in the head, and can snap shut on prey or objects when their corresponding latches on the clypeus are triggered. The great instantaneous speed of the muscles is due to elastic energy, like the elastic energy of a crossbow. According to Wikimedia (2013), the jaws of Odontomachus are the fastest moving predatory appendages in the animal kingdom. One study of O. bauri at UC Berkeley's Department of Integrative Biology (2006) recorded peak speeds of between 35-64 meters per second (78-145 mph), with the jaws closing within just 0.13 milliseconds (130 microseconds) on average. This is 2,300 times faster than the blink of an eye! The peak force exerted was 100,000 times the force of gravity or 300 times the ant's body weight. The mandibles either kill or maim prey, allowing the ant to bring it back to the nest. Odontomachus can simply open and relock its jaws if one bite is not enough. It can use its jaws to bite off larger chunks of food. The ants were also observed to use their jaws as a catapult to eject intruders or fling themselves backwards to escape a threat.

According to Sheila Patek of the integrative biology research team at UC Berkeley (2006), falcons can dive at speeds up to 300 miles per hour, but they must start from very high altitudes and get a boost from the force of gravity to reach these high speeds (32 feet per second squared). In comparison, animals such as trap-jaw ants and mantis shrimp (which formerly held the record for swiftest strike in the animal world) utilize energy stored within their own bodies. In the plant kingdom, one of the fastest moving structures is the trapdoor of an aquatic bladderwort (Utricularia) that snaps shut in 15 to 20 milliseconds (about 1/60 of a second), roughly the speed of a daylight film camera shutter setting. Compare this rate with 0.13 milliseconds for jaws of Odontomachus bauri! Using the formula Force = Mass X Acceleration, it is easy to see how these small ants can stun or kill small prey with their powerful, fast-moving jaws.

Patek, S.M., Baio, J.E., Fisher, B.L., and A.V. Suarez. 2006. "Multifunctionality and Mechanical Origins: Ballistic Jaw Propulsion in Trap-Jaw Ants." Proceedings of the National Academy of Sciences 103 (34): 12787-12792. Full Article

Subfamily Formicinae: Yellow Crazy Ant Anoplolepis gracilipes

Ground nests of long-legged ant were common near coconut palms at the Maui Tropical Plantation, and in a restroom on Molokai.

Subfamily Dolichoderinae: Ghost Ant (Tapinoma melanocephalum)

The ghost ant (Tapinoma melanocephalum) is easily recognizable by its minute size (1.5 mm long), dark head & thorax, and translucent gaster. It is very fond of sugar and was common on my sink counter where I placed dissolved sucrose near a U.S. dime. It belongs to the same subfamily as black house ants (T. sessile), Argentine ants (Linepthema humile), and orange desert ants (Forelius pruinosus).

Subfamily Formicinae: Long-Horned Crazy Ant (Paratrechina) & Brachymyrmex obscurior

Two additional ant species from the Wailea area of southern Maui.