Diversity of Spider Fauna in Upland Rice Agroecosystem at Gudalur Valley in Tamilnadu

Abstract

The diversity of spiders and impact of pest population on spider density has been studied in the upland rice agroecosystem in Bharathy variety at Hybrid Rice Evaluation Centre, Tamil Nadu Agricultural University, Gudalur, The Nilgiris during Kharif 2010 and 2011. Three aspects, population of spiders and pests in different rice establishment techniques, diversity of spider species in different rice establishment techniques and impact of pest density on the population of spiders were studied. A total of 11 species of spider from 7 different families were observed from all the three different techniques of upland rice crop at different days after transplantation. Among the spider species, Lycosa pseudoannulata was higher in early growth stage and Tetragnatha javana was predominant in later stages of the crop. Population of brown plant hopper, green leaf hopper and stem borer showed significant positive impact on L. pseudoannulata and Oxyopes javanus population. Regression analysis revealed that 97 percent of L. pseudoannulata, 72 percent of O. javanus, 94 percent of T. javana and 80 percent of Clubiona sp. population depends on the incidence of pests in the upland rice ecosystem. Diversity indices revealed that diversity of spider was more in the direct sown method than transplanting and seedling throwing method.