DIVERSITY AND POPULATION DYNAMICS OF SPIDERS IN AGROECOSYSTEMS

Abstract

The biodiversity of spiders in agroecosystem was studied at the Pandit Jawaharlal Nehru College of Agriculture and Research Institute, Karaikal during kharif (2019) and rabi (2019-20). The spiders were collected at weekly intervals using in situ counts, net sweeping, pitfall traps and litter sampling. A total of 30 species under 22 genera, 15 families were observed. Biodiversity indices viz., Shannon-Weiner Index (2.809- kharif and 2.766- rabi), Simpson Index (0.926- kharif and 0.909- rabi), Margalef Index (4.135-kharif and 4.22- rabi) and Pielou’s Index (0.104- kharif and 0.095- rabi) were computed. Regression with weather parameters during kharif 2019, were non-significant for Thomisus sp. (0.107), Pardosa sumatrana Thorell (0.146), Oxyopes javanus Thorell (0.190), Tetragnatha javana Thorell (0.213) and Tetragnatha mandibulataWalckenaer (0.347); and during rabi 2019-20, for T. javana (0.516), Argiope anasuja Thorell (0.619) showed significance and O. javanus (0.192), Lycosa bistriata Gravely (0.370), T. mandibulata (0.437), these values were non-significant.