| Abstrakt: |
Neonicotinoids are the most widely used insecticides world-wide, but their fate in the environment remains unclear, as does their potential to influence non-target species and the roles they play in agroecosystems., We investigated in laboratory and field studies the influence of the neonicotinoid thiamethoxam, applied as a coating to soya bean seeds, on interactions among soya beans, non-target molluscan herbivores and their insect predators., In the laboratory, the pest slug Deroceras reticulatum was unaffected by thiamethoxam, but transmitted the toxin to predaceous beetles ( Chlaenius tricolor), impairing or killing >60%., In the field, thiamethoxam-based seed treatments depressed activity-density of arthropod predators, thereby relaxing predation of slugs and reducing soya bean densities by 19% and yield by 5%., Neonicotinoid residue analyses revealed that insecticide concentrations declined through the food chain, but levels in field-collected slugs (up to 500 ng g−1) were still high enough to harm insect predators., Synthesis and applications. Our findings reveal a previously unconsidered ecological pathway through which neonicotinoid use can unintentionally reduce biological control and crop yield. Trophic transfer of neonicotinoids challenges the notion that seed-applied toxins precisely target herbivorous pests and highlights the need to consider predatory arthropods and soil communities in neonicotinoid risk assessment and stewardship. [ABSTRACT FROM AUTHOR] |
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