Bumblebees die from Roundup® co-formulants, not glyphosate

Bumblebees (*Bombus terrestris audax*) exposed to Roundup® herbicides showed high mortality: 94% with Ready-To-Use, 96% with No Glyphosate, and 30% with ProActive, while Weedol® (glyphosate-only) caused no significant mortality. This indicates co-formulants—not glyphosate—are likely responsible for acute toxicity, possibly via surfactant-induced disruption of gas exchange. The study urges regulatory changes to restrict spraying during foraging, mandate full ingredient disclosure, and revise toxicity testing to include non-glyphosate components. Findings are based on 10 colonies tested across five experiments using Cox proportional hazards models.