ORIGINAL ABSTRACT

BACKGROUND: With the increasing use of glyphosate, residues have been detected in many organisms, raising concerns about impacts on animal health and ecosystems. The present study addressed the biological question: How does glyphosate exposure, at environmentally relevant and higher concentrations, affect the survival, growth, reproduction, and carbohydrate metabolism of the ladybird Harmonia axyridis (Pallas), a key natural enemy of aphid pests? To simulate food chain contamination, aphids were fed glyphosate-sprayed broad bean seedlings and then fed to H. axyridis. RESULTS: Glyphosate residues were found throughout the broad bean-aphid-ladybird system, with the highest levels in broad bean roots (85 mg/L) and adult ladybirds (74 mg/L). Exposure to glyphosate concentrations ≥ 50 mg/L affects the growth and development of H. axyridis, with higher concentrations having a considerable impact. Concentrations ≥ 100 mg/L significantly decreased oviposition and egg hatching rates. At the molecular level, glyphosate exposure caused down-regulation of the TRE1-1 gene during the fourth instar, pupa, and adult stages, along with decreased trehalase activity and increased trehalose content, indicating disrupted carbohydrate metabolism. Glucose and glycogen levels remained unaffected. CONCLUSION: This combination of trophic transfer assays and molecular analyses clarifies glyphosate's detrimental effects on a key beneficial predator, emphasizing the importance of cautious herbicide management for preserving natural pest control services and maintaining ecological balance in agricultural ecosystems. This is a measure that can help mitigate the cascading risks of herbicide misuse to field-level biological pest suppression. © 2026 Society of Chemical Industry.