Diversity and seasonal occurrence of odonates in the dry deciduous ecoregion of Purulia, West Bengal, India

Abstract

A year-long study was conducted in the dry deciduous ecoregion of Purulia, West Bengal, India from March 2018 to February 2019 to document the diversity, species composition, and occurrence of odonata species in different seasons. Direct search and opportunistic sighting methods were used in combination at five selected sites, namely, the Sidho-Kanho-Birsha University campus, Saheb Bandh, the Surulia Deer Park (Mini Zoo), Ketika, and the Kansai river-side. A total of 11,471 individuals belonging to 8 families and 40 species were recorded during the study period. Anisoptera (dragonflies) were represented by 29 species belonging to 4 families, whereas Zygoptera (damselflies) were also found to be represented by 4 families but only 11 species. Libellulidae were found to be the largest family represented by 24 species, while the ground skimmer Diplacodes trivialis was the most dominant species. Species richness was the highest in the post-monsoon, whereas the Shannon diversity index was found to reach maximum values in winter. Overall, we conclude that the town of Purulia and its adjoining area with its patchy vegetation and extreme weather conditions have moderate odonate diversity.