Natures wonders: ant jaw snap speed (Introduction)

by David Turell , Thursday, August 31, 2017, 15:31 (2639 days ago) @ dhw

One type of ant snaps its jaws shut at amazing speed with a special triggering mechanism:

https://cosmosmagazine.com/biology/ant-jaws-snap-shut-700-times-quicker-than-a-blink-of...

"Researchers led by Fredrick Larabee from the Smithsonian National Museum of Natural History set out to determine just how fast one genus of trap-jaw ants can slam shut their jaws. The answer: 80 km/h.

"This means that if you happen to be the ant’s natural prey – tiny arthropods known as springtails – you have virtually no chance of getting out of the way in time.

"The trap-jaw genus, known as Myrmoteras, is found primarily in Southeast Asia. To achieve the high-speed jaw snap, the ants’ mandibles latch into place at a 280-degree angle – tensed, possessing considerable stored elastic energy.

"Slipping the latch releases that energy, causing the jaws to snap shut in half a millisecond – about 700 times faster than it takes a human eye to blink.

"The speed of the mandible action is far faster than could be achieved if the ants relied solely on their musculature. The scientists detected notches on the jaws that allowed them to wedge open. A lobe on the back of the ant’s head acting as a trigger; its compression releases the latch.

***

"Trap-jaw ants of the Odontomachus genus have jaws that, using a similar mechanism, snap shut at twice the speed. This ability is used for hunting and also to propel the ants backwards as a maneouvre to avoid predators.

"The Myrmoteras ants do not seem to use their jaws for similar evasive purposes. "They just need to be faster than the critters they're trying to eat,” Larabee says, “and their jaws are plenty fast for capturing springtails."

"Another Smithsonian team discovered in 2016 that a family of South American and New Zealand spiders known as the Mecysmaucheniidae also hunt using a latch-based trap-jaw system to hunt.
Similar systems have been found for other functions in the arthropod world – propelling grasshopper and flea jumps, for instance. Though there are differences in biomechanics – Myrmoteras represents “a completely unique evolution,” Larabee says – the latch-and-release system represents an interesting example of convergent evolution."

Comment: The inventiveness in the bush of life is always amazing, especially as shown by this example of convergence.