Impact of insect-resistant transgenic rice on above-ground non-target arthropods in Korea

Transgenic rice (Bt-T event) shows resistance against rice leaf roller (Cnaphalocrocis medinalis) by expressing a toxic protein (mCry1Ac1) mediated from the soil bacterium Bacillus thuringiensis. Environmental risk assessment of Bt-T event, in addition to the parent variety Dongjin-byeo and cultivar Ilmi-byeo, was performed during the rice cultivation seasons of 2016 and 2017 at LMO quarantine fields in Gunwi and Jeonju, Korea. Non-target arthropods (insects and spiders) were captured using an aspirator from the three rice ecosystems of both locations, and in total 39,734 individuals of 57 families and 11 orders were collected. The numbers of individuals collected from the Bt-T, Dongjin-byeo and Ilmi-byeo rice ecosystems were 12,899, 12,730, and 14,105, respectively, which did not differ significantly among rice ecosystems. The dominance, diversity, evenness, and richness indices of the collected insects were not statistically different among the rice ecosystems, but significant variations between the two locations and survey years were detected. Principal component analysis showed that insects and spiders in the Bt-T, Dongjin-byeo, and Ilmi-byeo rice ecosystems were separated by the study locations and years irrespective of rice variety. In conclusion, results obtained in two consecutive years from two non-genetically modified rice ecosystems and a Bt-T rice ecosystem showed that the Bt-T rice had no significant negative impacts on the above-ground insect and spider communities.