Living in the searing hot Sahara Desert is no joke at all. But for the Saharan silver ant, this isn’t much of a problem — its own heat repellant system will take care of things.
The body hairs of this ant cause total internal light reflection, making them nearly 10 times more reflective. This prevents overheating and helps them maintain their silver coat, according to the findings of a new study from Belgian scientists.
This ant species is among land creatures that are best adapted for heat. It can forage in the high-temperature desert even at upwards 50 degrees Celsius.
"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,” explains study author Dr. Serge Aron from the Free University of Brussels.
He adds that this is the first time that internal reflection appears to determine an organism’s colors — in this case, a glittery silver hue for the ants.
The team analyzed the ant hairs and traced the direction of incoming light rays using a Scanning Electron Microscope. They compared samples of regular hairy ants with those of shaved ones, measuring light reflection and the speed at which the ants heated under artificial sunlight.
They discovered that hairy ants emerged nearly 10 times more reflective than shaved ones and stayed up to 2 degrees Celsius cooler under the simulated sunlight. In addition, the triangular cross-section as well as corrugated surface of every hair served as a prism for reflecting light, where the rays entering each hair experience total internal reflection.
The mirror effect provides the ants their silver sheen and decreases heat absorption, preventing the desert creatures from overheating.
Most arthropods maintain plate-like bristles on their body, which makes these characteristics unique to the Saharan silver ant. And while many other insects and animals living in the Sahara avoid scorching daytime heat, these ants have no such fear.
“Workers come out from the nest during the hottest midday period, when temperatures exceed 50 degrees Celsius, to scavenge corpses of heat-stricken animals,” the authors write, adding that foraging activity strictly performed during the hottest hours of the day enable the ants to minimize predator encounters.
The findings were published April 13 in the journal PLOS ONE.
