Guwahati: Deep within Arunachal Pradesh’s Upper Siang Valley, along the banks of the Kugging River, a groundbreaking scientific discovery has emerged — Microleptes sandeshkaduri, a newly identified species of parasitic Darwin wasp. This remarkable find, led by researchers from the Ashoka Trust for Research in Ecology and the Environment (ATREE) in collaboration with international scientists, sheds light on the region’s untapped biodiversity.
A team of scientists has documented five new species of the Darwin wasp subfamily Microleptinae (Hymenoptera: Ichneumonidae) from India and Thailand. These parasitic wasps, whose larvae consume their hosts from within, have been recorded in India for the first time.
Microleptes sandeshkaduri is one of four new species discovered in India, with the others being Microleptes chiani, M. gowrishankari, and M. tehriensis. The study, conducted by Ranjith A.P. and Priyadarsanan Dharma Rajan of ATREE, alongside collaborators Buntika A. Butcher of Chulalongkorn University in Thailand and Andrei E. Humala of the Russian Academy of Sciences, was recently published in the Journal of Hymenoptera Research.
The species are named in honour of individuals who have significantly contributed to biodiversity documentation and conservation. Microleptes sandeshkaduri was collected from the Siang Valley and named after Mr Sandesh Kadur of Felis Creations for his exceptional work in documenting and conserving biodiversity. M. chiani, discovered in Tamil Nadu’s Kalakad Mundanthurai Tiger Reserve, honours Tamilazhagan (popularly known as Chian), Senior Technical Assistant at ATREE. Meanwhile, M. gowrishankari, found in Karnataka’s Biligiri Ranganathaswamy Temple Tiger Reserve, pays tribute to Dr P. Gowri Shankar of the Kalinga Foundation for his efforts in King Cobra conservation.
Measuring just 3.8 mm, Microleptes sandeshkaduri belongs to the rare Microleptinae subfamily. Its discovery in the Arpong riverside area along the Kugging River highlights the Siang Valley’s significance as a hotspot for entomological research.
Over a century ago, during a colonial expedition accompanying a military operation in the region (1911–12), scientists documented 606 insect species. That historical effort, led by luminaries such as Dr Stanley Kemp, Superintendent of Indian Museums, laid the foundation for exploring the area’s biodiversity. However, the constraints of winter sampling meant the valley’s full ecological richness remained unexplored.
The ongoing “Siang Expedition,” funded by the National Geographic Society (NGS-71945c-20), seeks to fill these gaps. Led by Dr Priyadarsanan Dharma Rajan, Dr Ranjith A.P., Dr Seena Nayananan Karimbumkara, and Sahanashree Ramakrishnaiah, the multi-seasonal study has documented over 180 ant species, including four potentially new to science, and more than 80 dung beetle species, with 10 recorded in India for the first time.
Among the most striking discoveries are over 200 species of parasitic Hymenoptera, including six new genera and more than 30 new species. The subfamily Microleptinae, previously undocumented in India, has drawn significant interest from researchers and conservationists.
According to Dr Priyadarsanan Dharma Rajan, these findings underscore the immense biodiversity of the Indian subcontinent and the importance of taxonomic research in advancing conservation efforts. The discoveries position the Siang Valley as a critical area for studying the evolution and ecology of parasitic wasps in the Oriental region.
This renewed exploration of the Siang Valley not only builds upon its historical legacy but also paves the way for further revelations. As researchers continue analysing their collections, many more species await discovery, offering vital insights into the interconnected worlds of biodiversity, conservation, and scientific collaboration.