Spider Diversity and Abundance in Bt and Non-Bt Cotton Crops in Punjab, India

Bt cotton, expressing a gene for Bt-toxin specifically affects lepidopteran larvae, but little is known about its impact on spiders.This study recorded the diversity and abundance of spiders in both Bt (transgenic cotton PAU Bt 1) and non-Bt cotton crops along with the (F 2228) effect of other factors like crop stages and climate for two seasons.Spiders of nine genera and 11 species representing six families: Araneidae (37.68%),Oxyopidae (28.85%),Lycosidae (18.68%),Thomisidae (10.57%),Salticidae (3.80%), and Pisauridae (0.41%) were recorded with maximum species richness of family Araneidae followed by family Lycosidae, and families Oxyopidae, Thomisidae, Salticidae and Pisauridae.The Shannon-Weiner index and species evenness index were 1.42 and 0.59, respectively.Spider abundance was significantly higher in Bt cotton compared to non-Bt cotton indicating no adverse effect of Bt toxin on spiders.In both crops, the spider abundance was higher at the bollbearing and boll-opening stages.Additionally, there was a significant effect on spiders of mean temperature.T he study suggests that rich spider fauna of cotton crops be protected to utilize their full potential in the Integrated Insect Pest Management Program.