Diversity and abundance of odonates (Order: Odonata) in Gurudeniya, Kandy District, Sri Lanka

Abstract

The previously unexplored Gurudeniya region in Kandy district was surveyed for adult odonate diversity and abundance. Three habitats, i.e., along the “Thalathuoya” tributary, adjacent forest cover and a home garden, were selected for the study. Sampling was conducted twice a week, during 8 am − 9 am and 4 pm − 5 pm for three months from October to December 2021, along a 200 m × 4 m belt transect. Altogether, 1933 odonate individuals belonging to eight families and fourteen species were recorded and they represented 43 % of the suborder Anisoptera and 57 % of Zygoptera, respectively. We detected eight endemic, three endangered and four vulnerable species. The Libellulidae was found to be the most diverse family, comprised of four species inhabiting only the tributary area. Calopterygidae, Gomphidae and Platycnemididae had two species in each. Vestalis apicalis nigrescens, Euphaea splendens and Ceylonosticta bine, were recorded as common inhabitants at all the study sites. Vestalis apicalis nigrescens and Trithemis festiva were the dominant Zygopteran and Anisopteran species with 37 % and 30 % relative abundance, respectively. The tributary had the most diverse and abundant odonate community, comprising fourteen species and 70 % relative abundance with a Shannon-Wiener diversity index of 1.94. At all of the study sites, the family Calopterygidae was abundant in terms of tributary 44 %, woodland 78 % and residential garden 89 %, respectively. In the majority of the odonate species, males outnumbered females. The findings of this study elucidated the odonates at Gurudeniya within a short period of time. An extensive study is underway to determine the larval and adult assemblages.