Odonatologists have reconfirmed the presence of the elusive dragonfly species, Crocothemis erythraea, in the high-elevation regions of the southern Western Ghats. The species had previously been misidentified or overlooked in this region due to its close resemblance to the more widespread lowland species, Crocothemis servilia.
The genus Crocothemis in India includes two known species—C. servilia and C. erythraea. While C. servilia is common across lowland areas, C. erythraea is known from high-elevation habitats in parts of Europe and Asia, including the Himalayas.
Previous reports of C. erythraea from the Western Ghats were contested due to lack of physical specimens and confusion with C. servilia.
According to Kalesh Sadasivan, the lead author of the present study published in the International Journal of Odonatology, photographs of a potential C. erythraea specimen were taken from the Munnar high ranges during an annual faunal survey in 2018. These records were cited in a 2021 monograph on Kerala’s odonata fauna, but later removed from subsequent checklists following skepticism over the species’ identification by other researchers.
Field expeditions
This prompted multiple field expeditions between 2019 and 2023 in high-altitude sites across the Western Ghats, including Wagamon, Rajakumari, Pampadum Shola and Parambikulam. Specimens were collected and analysed using both morphological and molecular techniques.
Morphological identification focussed on diagnostic characteristics such as the male genitalia, especially the structure of the hamule. DNA barcoding was also carried out as part of the research.
The molecular analysis showed that the high-elevation specimens from the Western Ghats match C. erythraea found in the Himalayas. In contrast, C. servilia was confirmed in the lowlands of both the Himalayas and southern India.
The study confirmed that the Western Ghats hosts both the species, C. erythraea, which is restricted to cool, high-elevation habitats (>550 m), while C. servilia is common in lowland habitats (<600 m).
Cooler climates
The researchers explain that C. erythraea colonised southern India during the Pleistocene Ice Age, when cooler climatic conditions allowed temperate fauna to extend their range southward. As the climate warmed, these populations became stranded in montane locations like the Sholas and grasslands of Munnar and Parambikulam, where they survived in isolation.
Published – August 29, 2025 08:14 pm IST
