Taxonomic composition,structure and dynamics of carabid community (coleoptera : carabidae) in selected rice agro- ecosystems

Abstract

Taxonomic identification and community structure of Carabid beetles associated with two geographically different rice agro ecosystems, one in the high ranges (Ambalavayal, Wayanad) and the other in the low ranges (Pattambi, Palakkad) of the Kerala state is carried out. Checklist of the species and keys to the species with images are provided. Beetles were collected from the pre- harvest, harvest and post-harvest stages of the rice crop using light trap, pitfall trap and hand collection methods. Eighty-one carabid species belonging to thirteen subfamilies, nineteen tribes and forty-eight genera were identified with forty-four species from the highland rice agro-ecosystem and sixty-six species from the low land rice agro-ecosystem. The species list includes one new species, one first record from India, four first reports from south India, two first records from Kerala and nine species endemic to the Western Ghats and Sri Lanka hotspot of biodiversity. Clivina tranquebarica dominated the light trap collections and Elaphropus politus dominated the pitfall collections in highland rice agro-ecosystem and Clivina brevior dominated the light trap collections and Stenolophus quinquepustulatus dominated the pitfall collections in the low land rice agro-ecosystem. Subfamilies Scaritinae, Trechinae and Harpalinae dominated the light trap collections and Trechinae, Lebiinae and Scaritinae dominated the pitfall collections in the high land rice agro-ecosystem.Subfamilies Harpalinae, Lebiinae, Scaritinae and Trechinae dominated the light trap collections and Harpalinae, Lebiinae and Trechinae dominated the pitfall collections in the low land rice agro-ecosystems. Dominance of thesesubfamilies in the rice agro-ecosystems could be attributed to their moisture- loving nature, specialization to survive in wet habitats, prey availability, adaptations for rapid colonization and utilization of available niches. Overall abundance of Carabidae showed no significant variation with seasons (pre- harvest, harvest and post-harvest stages of rice cultivation) in both the rice agro-ecosystems. Record of eighty-one species of Carabidae from the rice agro-ecosystems, indicates the presence of rich fauna of Carabid beetles in the rice agro-ecosystem.