"Large consequences on ecosystem services such as pollination" could result

A new study by an international team of scientists shows that if Bt insecticidal or herbicide-tolerant GM maize is grown in Europe, this could threaten the continent's butterflies and moths (see abstract below).

The study found that Bt insecticidal maize can produce pollen that is toxic to lepidopteran larvae, and this puts butterfly species at possible risk if the presence of young larvae coincides with maize flowering, during which large quantities of maize pollen can be deposited on vegetation. The authors found that 31 species had at least one generation where 50% of the larval stage overlapped with maize flowering, and 69 species for which early-stage (first instar) larvae were present during maize pollen shedding.

Regarding herbicide-tolerant maize, the authors identified 140 protected species that feed on plants that are common weeds in one or more of the major European maize‐growing countries. If herbicide-tolerant maize is grown in Europe, the authors conclude that "there is a potential hazard that their food plants will seriously decline, causing a subsequent decline of these protected species".

The authors conclude, "The introduction of GM maize in Europe could potentially affect many species that live within or near to agricultural areas... with large consequences on ecosystem services such as pollination, on which agriculture ultimately depends.... Our results clearly show the importance of regionally protected species which gives EU Member States a clear mandate to consider possible risks of GM maize given their responsibility for national biodiversity conservation."
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Can the growing of transgenic maize threaten protected Lepidoptera in Europe?
Gábor L. Lövei, Andreas Lang, Marco Ferrante and Victor Bacle
Insect Science. 16 July 2020 https://doi.org/10.1111/1744-7917.12849
https://onlinelibrary.wiley.com/doi/abs/10.1111/1744-7917.12849

Abstract

We evaluated whether protected European butterflies can potentially be at risk if transgenic maize is extensively grown in Central Europe. We explored potential consequences of both insect resistant (IR) and herbicide resistant (HR) transgenic maize. IR maize can produce pollen that is toxic to lepidopteran larvae, and this puts butterfly species at possible risk if the presence of young larvae coincides with maize flowering, during which large quantities of maize pollen can be deposited on vegetation. By considering the timing of maize flowering in Europe, and the phenology of the protected Lepidoptera species, we found that 31 species had at least one generation where 50% of the larval stage overlapped with maize flowering, and 69 species for which first instar larvae were present during maize pollen shedding. HR maize allows high concentration herbicide treatments on fields without seasonal limitation, which can drastically reduce weed densities. In cases where such weed species are host plants for protected butterflies, reduced host plant/food availability can result, causing population decreases. By using published information, we first identified the important weed species in major maize‐growing European countries. Subsequently, we checked whether the host plants of protected Lepidoptera included species that are common maize weeds. We identified 140 protected species having food plants that are common weeds in one or more of the major European maize‐growing countries. If HR maize is grown in Europe, there is a potential hazard that their food plants will seriously decline, causing a subsequent decline of these protected species.