By snapping their jaws onto the ground, trap-jaw ants can flip backward and escape threats. Now an N.C. State evolutionary biologist reports that one kind of trap-jaws can also jump forward – using its legs instead.
Only three of 326 subfamilies of ants are known to jump. When ants jump backward, they have little control and often land on their backs, according to Magdalena Sorger.
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The species she studied, O. rixosus, is found in Southeast Asia. Other jumping ants have been found in South America, Australia, New Zealand and New Caledonia. But the one Sorger studied while doing field work in Borneo turns out to be the only ant species that can jump using either its jaws or legs.
Sorger’s paper on trap-jaw ants It isn’t clear exactly how trap-jaw ants manage to jump forward, though Sorger has done some preliminary tests. “I do know that they don’t use their front legs at all,” she said. “Somehow they are using hind legs.”
The new behavior, which Sorger calls a leg-jump, appears to be used primarily – if not exclusively – as an escape mechanism. Her paper was recently published in the journal Frontiers in Ecology and the Environment. ncsu.edu
400-year-old hearts show evidence of coronary disease
Researchers using modern imaging techniques on hearts more than 400 years old found at an archeological site were able to learn about the health conditions of the people buried there,
French archaeologists with the National Institute for Preventive Archaeological Research excavated the basement of a convent in Rennes, France, unearthed several grave sites dating back to the late 16th or early 17th century. Among the items unearthed in the burial vaults of elite-class families were five heart-shaped lead urns. Inside each urn was a preserved human heart.
The research team used MRI and CT to obtain clinical images of the hearts; other techniques were used to examine heart tissue. One heart appeared healthy and showed no signs of disease. Three of the hearts did show signs of signs of present-day heart conditions, such as plaque and atherosclerosis. The fifth heart had been poorly preserved and, therefore, could not be studied.
The findings were presented last week at the annual meeting of the Radiological Society of North America. rsna.org
Stretchable, wearable body sensor made with chewing gum
Body sensors allow any wearer to easily track heart rate, steps and sleep cycles around the clock. Soon, they could become even more versatile – with the help of chewing gum. Scientists report in the journal ACS Applied Materials & Interfaces a unique sensing device made of gum and carbon nanotubes that can move with your most bendable parts and track your breathing.
Most conventional sensors today are very sensitive and detect the slightest movement, but many are made out of metal. That means when they're twisted or pulled too much, they stop working. Some researchers have tried developing sensors using stretchy plastics and silicones, but what they gained in flexibility, they lost in sensitivity.
A team led by Malcolm Xing of the University of Manitoba found a better solution.
To make their supple sensor, a team member chewed a typical piece of gum for 30 minutes, washed it with ethanol and let it sit overnight. The researchers then added a solution of carbon nanotubes, the sensing material. Simple pulling and folding coaxed the tubes to align properly. Human finger-bending and head-turning tests showed the material could keep working with high sensitivity even when strained 530 percent. acs.org