Weedkiller Disrupts Honeybee Brains: Science Explained
🕐 9 min read | 🌍 Natural Wonders 🔒 Key Takeaways Global glyphosate use is estimated at roughly 800,000 tonnes a year, a close to 15-fold rise since herbicide-tolerant GM crops were introduced in 1996. In a 2015 Journal of Experimental Biology radar study, honeybees fed a 10 mg/L glyphosate solution flew longer, more indirect homing routes than unexposed bees. A 2018 PNAS study found that 5-10 mg/L glyphosate depletes Snodgrassella alvi, a core honeybee gut symbiont, and raises mortality from the opportunistic pathogen Serratia marcescens. Bumblebee (Bombus terrestris) colonies exposed to glyphosate in a 2022 Science study lost roughly a quarter of their brood-warming capacity when food was scarce, failing to hold the 32-36°C pupae need. Standard bee approval tests (OECD guidelines 213 and 214) measure death within 48-96 hours, not learning, memory, homing success or gut microbiome composition. It was marketed as the near-perfect herbicide: a molecule aimed so...