Transgenic Cry1Ac+CpTI cotton does not compromise parasitoid-mediated biological control: An eight-year case study

BACKGROUND: The on-farm deployment of genetically modified crops may negatively affect nontarget arthropods, potentially disrupting food web structure and ecosystem functions. Aphid-parasitoid interactions are well-suited to study these potential impacts in agro-ecosystems. Over the span of 8 years, we systematically compared infestation levels of the aphid Aphis gossypii, its associated parasitoid community and overall parasitism rate between transgenic Cry1Ac + CpTI cotton and nontransgenic cotton. Furthermore, we measured the impact of transgenic Cry1Ac + CpTI cotton on structural traits and interspecies interactions within quantitative aphid-parasitoid food webs. RESULTS: Transgenic Cry1Ac + CpTI cotton did not affect the abundance of aphids and parasitoids, or in-field parasitism rates. Despite weak interannual variability, transgenic Cry1Ac + CpTI cotton also did not alter food web architecture or biological control services. CONCLUSIONS: Our work not only elucidates the impact of transgenic Cry1Ac + CpTI cotton on different nontarget arthropods (i.e. aphids, parasitoids, hyperparasitoids) and their associated ecosystem services or disservices, but also diversifies the ecological risk assessment toolbox for transgenic insecticidal crops. (c) 2021 Society of Chemical Industry.

Automated summary

The study found that transgenic Cry1Ac + CpTI cotton did not have significant effects on aphid and parasitoid abundance, in-field parasitism rates, or food web structure. This work not only provides new insights into the ecological risk assessment of transgenic insecticidal crops, but also offers important data on the impact of nontarget arthropods in agro-ecosystems.