A group of entomologists have documented the odonate fauna in Kerala for the first time. Home to 181 species of dragonflies and damselflies, the State also nurtures 68 species that are endemic to the Western Ghats.
The comprehensive study undertaken by Vinayan P. Nair, K. Abraham Samuel and Kalesh Sadasivan of Travancore Nature History Society and Muhamed Jafer Palot of Zoological Survey of India that reviews the current status and distribution of odonates have been published in the latest edition of Entomon, a peer-reviewed journal issued by the Association for Advancement of Entomology.
According to the study, the current checklist of odonates of the Western Ghats stood at 207, of which 80 species are endemics. A total of 181 species belonging to 87 genera under two suborders and 14 families were recorded within the geographical boundaries of Kerala. The suborder Zygoptera comprises 74 species of damselflies (30 genera in seven families) and the suborder Anisoptera has 107 species (57 genera in seven families).
While the group initially compiled data on 169 species from scattered literature, the authors added eight species based on their personal records and publications. These odonate species include Amphiallagma parvum, Ceriagrion chromothorax, Platylestes platystylus Rambur , Pseudagrion australasiae Selys , Crocothemis erythraea, Protosticta rufostigma Kimmins , Protosticta sholai Subramanian & Babu , and Zygonyx torridus isis Fraser .
Another four species - Paracercion malayanum Selys, 1876 by Bo Nielson from Varkala, Indothemis limbata sita Campion, 1923 and Indolestes pulcherrimus Fraser , 1924 by Muneer PK from Wayanad; and Anax indicus Leiftinck, 1942 by Suhas R.K. from Chinnar— were also included from the personal records of other researchers.
A landscape-based approach has been adopted to list the odonata distribution along Agasthyamala, Periyar, Munnar, Nilgiri, Wayanad and Coorg.
According to the International Union for Conservation of Nature (IUCN) Red List of Threatened Species of 2021, the state has one ‘endangered’ species ( Idionyx galeata ), four ‘near threatened’ and ‘vulnerable’ species each. Besides, 130 species in Western Ghats were considered to be of ‘least concern’, while 50 others belonged to the ‘data deficient’ category. Interestingly, none of the species is listed in the Wildlife Protection Act, 1972.
Dr. Kalesh pointed out studies on odonates of the Western Ghats have been meagre compared to vertebrate groups. While the researchers found recent data on almost all known species, they could not rediscover two species - Idionyx nadganiensis Fraser, 1924 and Idionyx periyashola Fraser, 1939 — which are known to have been discovered in Nadukani, Malappuram and Periyashola close to Top Station, near Munnar. However, it was too early to deem them extinct, the researcher said.