Honey bee queens with 1ppb imidacloprid treatment during larval stage, replicate 2
Twenty l of Royal jelly containing 1 ppb of imidacloprid or 0.1% of DMSO was added to queen cells. A total of 30 2-day-old worker bee larvae were carefully picked and moved into artificial queen cells with RJ containing either 1 ppb imidacloprid with 0.1% DMSO (treatment) or 0.1% DMSO only (control), one larva per cup. The frames of queen cups were then put into a healthy beehive, one frame per hive. The next day, the frames were taken out of the hive, 20 l of RJ containing 1 ppb imidacloprid (0.1%DMSO) or with only 0.1% DMSO was added into queen cups in touch with the head of larvae (supplementary Fig. 1). Imidacloprid treatment was performed for consecutive 3 days.