Quantification of the abundance and diversity of predatory spiders in rice ecosystem of Rajendranagar, Telangana, India

Abstract

The effective prey searching ability and polyphagy of spiders makes them important predators of crop pests. 19 species of spiders have been recorded in rice ecosystem (Rajeswaran et al., 2005). There is now a growing need to conserve all species and not only the large vertebrates (Samways, 1990) and contribute to the natural biological process. However, literature pertaining to their abundance and diversity in rice crop in Rajendranagar area is scant. Hence, the p resent study was conducted to understand their abundance and diversity. Spider samples were collected from rice fields of Rajendranagar in kharif and rabi seasons of 2011-12 and 2012-13. A total of 2,094 individuals collected in kharif represented eight families with a density of 12.48/sq.m. Members of Tetragnathidae were recorded most abundantly in kharif (46.32% of the Arachnid population) followed by Lycosids (26.22%). In rabi 1,095 spiders of seven families were collected with a density of 6.38/sq.m. Tetragnathidae and
Lycosidae were the most abundantly found species in rabi also comprising 27.85% and 26.12% of Arachnid population respectively. Study of guild composition was also carried out. A t-test between indices of richness, diversity, effective no.of species and species evenness of kharif and rabi seasons revealed that there were no significant differences with respect to these parameters (p>0.05) indicating that spider diversity of rice in Rajendranagar was more or less same between kharif and rabi seasons. This is the first study on the spider diversity of rice ecosystem of Rajendranagar, Hyderabad, India.