New ant species discovered from Siang Valley in Arunachal Pradesh

Discovering a new blue ant species in the Eastern Himalayas, researchers highlight biodiversity threats in Siang Valley.

Researchers have discovered a new ant species from the Eastern Himalayas. Belonging to the rare genus Paraparatrechina, the blue-coloured insect has been named Paraparatrechina neela.

The discovery was made by entomologists Priyadarsanan Dharma Rajan and Sahanashree R. from Ashoka Trust for Research in Ecology and the Environment (ATREE) in Bengaluru and Aswaj Punnath from the University of Florida. Their scientific description of the ant has been published in the peer-reviewed journal ZooKeys.

According to the researchers, the discovery, made during an expedition to Siang Valley in Arunachal Pradesh, marks the first addition to the Paraparatrechina genus from the Indian subcontinent, since the description of the sole previously known species P. aseta 121 years ago. “While exploring a tree hole about 10 feet up in a steep cattle track in the remote Yingku village in Arunachal Pradesh, something sparkled in the twilight. With the dim light available, two insects were sucked into an aspirator. To our surprise, we later found that they were ants,” the researchers said.

Paraparatrechina neela has been described as a small ant with a total length of less than 2mm. Its body is predominantly metallic blue, except for the antennae, mandibles, and legs. The head is subtriangular with large eyes and has a triangular mouthpart (mandible) featuring five teeth. The researchers said that although the blue colouration was commonly observed in some insects like butterflies, beetles, bees, and wasps, it was relatively rare in ants. Out of the 16,724 known species and subspecies of ants worldwide, only a few exhibit at least partial blue colouration or iridescence, they noted.

More than a century after a scientific team that accompanied the ‘Abhor expedition’, a punitive military expedition against the local tribes, documented the natural history and geography of the Siang Valley, a team of researchers from the ATREE is in the process of resurveying and documenting the biodiversity of the region. The expedition was funded by the National Geographic Society through the wildlife-conservation expedition grant. Entomologists from ATREE have so far discovered a new subfamily, six new genera and more than 40 new insect species, belonging to parasitic wasps, ants and beetles from the region.

Dr. Rajan said that despite being a biodiversity hotspot, Siang Valley was facing “unprecedented threats”. “Large-scale infrastructure projects like dams, highways, and military installations, along with climate change, are rapidly altering the valley. The impact extends beyond the valley itself, as these mountains play a critical role not only in sustaining their diverse ecosystems but also in ensuring the well-being of millions of people living downstream,” he said.