Crocothemis Erythraea
Recent research has confirmed the presence of the rare dragonfly species Crocothemis erythraea in the high-elevation areas of the southern Western Ghats. Earlier, this species was often confused with the widespread lowland species Crocothemis servilia. This rediscovery marks the significance of detailed field studies and modern scientific methods in biodiversity documentation.
Species Overview
The genus Crocothemis in India includes two species – Crocothemis servilia and Crocothemis erythraea. C. servilia is common in lowland regions. C. erythraea, however, prefers cooler, high-altitude habitats. It is known from parts of Europe, Asia, and the Himalayas. The presence of C. erythraea in the Western Ghats was uncertain due to misidentification and lack of physical evidence.
Field Expeditions and Identification
Between 2019 and 2023, multiple field expeditions were conducted in high-altitude sites such as Wagamon, Rajakumari, Pampadum Shola, and Parambikulam. Specimens were collected for detailed study. Identification used both morphological traits and DNA barcoding. Key features included the male genitalia, especially the hamule structure. Molecular analysis confirmed that the Western Ghats specimens matched C. erythraea from the Himalayas.
Habitat and Distribution
The study showed that C. erythraea is restricted to cool, high-elevation areas above 550 metres. These habitats include montane shola forests and grasslands. In contrast, C. servilia is found in lowlands below 600 metres. This altitudinal segregation explains earlier confusion between the species.
Historical Biogeography
Researchers suggest that C. erythraea colonised southern India during the Pleistocene Ice Age. Cooler climates then allowed temperate species to expand southwards. As the climate warmed, these populations became isolated in cooler montane refuges. This isolation in the Western Ghats allowed C. erythraea to survive in pockets like Munnar and Parambikulam.
Significance of the Study
This rediscovery clarifies the distribution of Crocothemis species in India. It emphasises the importance of combining fieldwork with molecular tools. It also marks the Western Ghats as a refuge for temperate species during climate change. The findings contribute to biodiversity conservation and ecological understanding of montane ecosystems.
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