Effect of abiotic factors and seasonal influence on spider diversity in rice agroecosystem of Bargarh District, Odisha, India

Abstract

Spiders are generalist predators which have been found to benefit paddy crops as biological control agents. The present study was taken up at Bargarh district of Odisha, India to study and compare the spider diversity in the two cropping seasons with effect of abiotic factors on species abundance in rice lands. The observations were made across two cropping seasons during Rabi and Kharif cropping seasons to assess the seasonal influence on spider population. Seventeen families of spiders were recorded during the study out of which Rabi cropping season recorded 17 families, while Kharif season recorded 13 families. In total, 60 genera and 93 species were identified based on 2694 individuals collected where females recorded 67.6% while 18.8% were juveniles and 13.6% were male spiders. The highest species diversity was found in Araneidae family (28) while Tetragnathidae (n=1106) recorded the highest abundance. The correlation of spider abundance with abiotic factors was found to vary in both cropping seasons, where rainfall and windspeed were found to control spider colonization to a considerable extent but not found significantly corelated to abundance, while it was strongly correlated positively with relative humidity. Spider abundance and species diversity was more in the Rabi season (summer crop). Five dominant families were reported commonly from both cropping seasons: Tetragnathidae, Araneidae, Lycosidae, Salticidae and Oxyopidae. Spiders observed during the study belonged to seven different feeding guilds.

Keywords

• agroecosystem
• rainfall
• rice harvesting seasons
• spiders
• stressors
• wind speed