In the lush forests of India’s Arunachal Pradesh, a team of intrepid researchers has made a startling discovery: a never-before-seen species of ant that sparkles like a brilliant blue gemstone. The remarkable find marks the first new species of its genus to be identified in India in over 120 years.
Dubbing the species Paraparatrechina neela, the fascinating discovery was made by entomologists Dr. Priyadarsanan Dharma Rajan and Ramakrishnaiah Sahanashree, from the Ashoka Trust for Research in Ecology and the Environment (ATREE) in Bengaluru, along with Aswaj Punnath from the University of Florida. The name “neela” comes from Indian languages, meaning the color blue. And for good reason – this ant sports an eye-catching iridescent blue exoskeleton, unlike anything seen before in its genus.
Paraparatrechina is a widespread group of ants found across Asia, Africa, Australia and the Pacific. They are typically small, measuring just a few millimeters in length. Before this discovery, India was home to only one known species in the genus, Paraparatrechina aseta, which was described way back in 1902.
The researchers collected the dazzling P. neela specimens during an expedition in 2022 to the Siang Valley in the foothills of the Eastern Himalayas. Fittingly, this trip was part of a series called the “Siang Expeditions” – a project aiming to retrace the steps of a historic 1911-12 expedition that documented the region’s biodiversity.
Over a century later, the area still holds surprises. The team found the ants living in a tree hole in a patch of secondary forest, at an altitude of around 800 meters. After carefully extracting a couple of specimens with an aspirator device, they brought them back to the lab for a closer look under the microscope. Their findings are published in the journal ZooKeys.
Beyond its “captivating metallic-blue color,” a unique combination of physical features distinguishes P. neela from its relatives. The body is largely blue, but the legs and antennae fade to a brownish-white. Compared to the light brown, rectangular head of its closest Indian relative, P. aseta, the sapphire ant has a subtriangular head. It also has one less tooth on its mandibles and a distinctly raised section on its propodeum (the first abdominal segment that’s fused to the thorax).
So what’s behind the blue? While pigments provide color for some creatures, in insects, hues like blue are usually the result of microscopic structural arrangements that reflect light in particular ways. Different layers and shapes of the exoskeleton can interact with light to produce shimmering, iridescent effects. This has evolved independently in many insect groups, but is very rare in ants.
The function of the blue coloration remains a mystery for now. In other animals, such striking hues can serve many possible roles – from communication and camouflage to thermoregulation.
“This vibrant feature raises intriguing questions. Does it help in communication, camouflage, or other ecological interactions? Delving into the evolution of this conspicuous coloration and its connections to elevation and the biology of P. neela presents an exciting avenue for research,” the authors write.
The Eastern Himalayas are known to be a biodiversity hotspot, but remain underexplored by scientists. Finding a new species of ant, in a genus that specializes in tiny, inconspicuous creatures, hints at the many more discoveries that likely await in the region’s forests. Who knows – maybe there are entire rainbow-hued colonies of ants hidden in the treetops!
