Meet the Saharan silver ant, the beautiful, mercury-colored insect capable of withstanding some of the most extreme temperatures on earth.
The findings of a new study published Wednesday in the open access journal PLOS One help explain how the shiny little fellows survive the Sahara desert, one of the hottest environments on the planet: their tiny metallic hairs block the harsh sun and act as the ant’s own personal heat-repellent system.
In a process scientists call “total internal reflection,” the ant’s silvery hairs have geometric properties that keep the insects cool in the scorching desert heat. Researchers at the Free University of Brussels in Belgium say triangular hairs reflect the incoming sunlight like tiny prisms or mirrors, assisting the ant’s thermoregulation and giving them their distinctive chrome-like appearance.
“The hairs have a triangular cross-section with two corrugated surfaces allowing a high optical reflection in the visible and near-infrared (NIR) range of the spectrum while maximizing heat emissivity in the mid-infrared (MIR). Those two effects account for remarkable thermoregulatory properties, enabling the ant to maintain a lower thermal steady state and to cope with the high temperature of its natural habitat.”
This allows Saharan silver ants, or Cataglyphis bombycina, to survive and even thrive in temperatures exceeding 122 degrees Fahrenheit (50 degrees Celsius). In the study, the researchers demonstrate how these special hairs work across a broad range of the electromagnetic spectrum, reflecting both visible and infrared light.
The triangular cross-section and the grooved surface of each hair causes light to bounce off the bottom of the hair instead of going right through it, in essence acting like a tiny reflecting mirror. This also helps shed body heat in the mid-infrared spectral range.
This ant species is among the best-evolved creatures to survive the difficult climate of the Sahara desert, according to the Christian Science Monitor.
“Most of the Sahara’s native animal species emerge only at the coolest points in the day, when the brutal sun is low or absent. Many Saharan predators would gladly snack on a silver ant, except for one thing – these lustrous bugs leave their dens only at the day’s hottest point.”
Saharan silver ants were the subject of rigorous testing by the international team of scientists that discovered the true nature of their silver coats, Gizmodo reported.
“A research team from the Free University of Brussels studied these hairs under an electron microscope to trace the path of incoming light rays. They also compared normal ‘hairy’ silver ants with a sample of silver ants that had their hairs removed (the researchers used a tiny scalpel to shave the ants, which must’ve been incredibly tedious).”
The results of the tests showed that the unshaved ants were able to stay up to two degrees Celsius cooler than the shaved ants in simulated sunlight, and that the hairs provided a 10-fold increase in light reflection. Though the Saharan silver ant boasts this natural protection, any more than 10 minutes of unprotected exposure to desert sunlight could mean death for them, so they compensate by sprinting at 70 times their length per second.
“The ability to reflect solar radiation by mean of total internal reflection is a novel adaptive mechanism in desert animals, which gives an efficient thermal protection against the intense solar radiation,” Dr. Serge Aron, one of the head researchers on the project, explained to the Tech Times.
Dr. Aron also stated that this is the first time that an organism’s colors have been determined by internal reflection.
It is hoped these latest findings on the thermal-radiative properties of the silver ants will help inspire a range of special coatings to allow passive radiative cooling for objects such as vehicles, buildings, or personal clothing in the future.
[Photo by David McNew/Getty Images]