Dynamic monitoring of the impact of insect-resistant transgenic poplar field stands on arthropod communities

Abstract

The safety of genetically modified forest trees is an important ecological issue worldwide, and concerns about genetic modification are one factor hindering in-depth research and large-scale planting of genetically modified trees. This study evaluated the impact of transgenic poplars on the ecosystem by analyzing differences in arthropod communities, target arthropods, and nontarget arthropods in transgenic (BtCryIAc) and non-transgenic experimental forests of Populus × euramericana cv. “74/76” (hereafter, tPE and ntPE, respectively). Five years of dynamic monitoring showed that the tPE had stable and lasting insect resistance to Lepidoptera, especially Arctiidae. However, the insertion of exogenous genes also had a negative impact on certain tPE line. The principle response curves (PRC) indicated that the genetic modification contributed much less to the community difference than the year factor (7% vs. 60%, respectively), and nontarget arthropods may be more sensitive to interannual variations. Nontarget arthropods that respond sharply to the PRC curve include Aphididae and Tenthredinidae (species weight > 0.5), but this difference appears only in certain years or lines. Our research shows that the tPE had no obvious adverse effects on nontarget arthropods. In areas with severe lepidopteran pests, the tPE could help to increase the diversity and stability of arthropod communities, while providing greater ecological and economic benefits than non-transgenic poplars.