Thrips-mediated impacts from Bt rice on ecological fitness of non-target predator Orius tantilus (Hemiptera: Anthocoridae)

This paper depicts the effects of transgenic rice lines KMD1 and KMD2 expressing Cry1Ab as compared to control on non-target predator under laboratory and field conditions. In laboratory, nymphal and adult development, reproductive parameters and total life cycle of Orius tantilus (predator of thrips), reared on thrips and pollens of transgenic rice lines KMD1 and KMD2 as compared to their non-Bt control Xiushui 11 were investigated. Protein test ELISA was carried out to determine the concentration of Bt protein in the O. tantilus and leaves of Bt rice. No significant difference in developmental time, reproductive parameters and total life cycle of Orius tantilus were found when reared on transgenic rice lines as compared to control. Nonetheless ELISA showed higher Bt concentration in pollens of Bt rice lines, in defiance no Bt toxin in O. tantilus was found. Two year field experiment to assess the population dynamics and seasonal average densities of Orius tantilus on KMD1 and KMD2 as compared to their control was carried out. Population dynamics confer the predators were found more or same in transgenic cultivars KMD1 and KMD2 as compared to control Xiushui 11 during 2009 and 2011. Seasonal average densities of O. tantilus revealed that there were either higher or same densities collected from transgenic Bt rice lines and their non-Bt parental cultivar suggesting that transgenic rice presumably enhance the population of predators in the field and not interacting with biological control hence not sought to pose intimidate effects on O. tantilus in the paddy fields.