Effect of Sub-Lethal Doses of Thiamethoxam on the Memory of Apis mellifera Linnaeus

Honey bees forage owing to their remarkable ability to learn and memorize their cues. The effect of thiamethoxam on the memory of bees was studied through the proboscis extension reflex (PER). The bees that consumed higher doses of thiamethoxam (0.93–5.76 ng bee^–1) showed lesser sensitivity to sucrose than those that consumed lower doses (0.03–0.64 ng bee^–1). Bees sensitivity was least affected at the highest sucrose concentration (50% w/v). PER in trained and treated bees recorded after 2 and 24 h of consuming the various doses of thiamethoxam showed a significant reduction in memory (13.3–82.2% and 0.00–68.9% respectively). Field-level studies are required to validate the results and formulate strategies at the national level for safeguarding the bees.